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PURPOSE: To report short-term results of pulsed ciliary muscle electrostimulation to improve near vision, likely through restoring accommodation in patients with emmetropic presbyopia. METHODS: In a prospective non-randomized trial, 27 patients from 40 to 51 years old were treated and 13 age- and refraction-matched individuals served as untreated controls. All patients had emmetropia and needed near sphere add between +0.75 and +1.50 diopters. The protocol included four sessions (one every 2 weeks within a 2-month period) of bilateral pulsed (2 sec on; 6 sec off) micro-electrostimulation with 26 mA for 8 minutes, using a commercially available medical device. The uncorrected distance visual acuity (UDVA) (logMAR) for each eye, uncorrected near (40 cm) visual acuity in each eye (UNVA) and with both eyes (UNVA OU) (logMAR), and reading speed (number of words read per minute at 40 cm) were measured preoperatively and 2 weeks after each session. Overall satisfaction (0 to 4 scale) was assessed 2 weeks after the last session. RESULTS: UDVA did not change and no adverse events were noted in either group. Bilateral and monocular UNVA and reading speed were stable in the control group, whereas they continuously improved in the treated group (Friedman, P < .00001). Post-hoc significant differences were found for monocular and binocular UNVA after the second treatment and after the first treatment considering words read per minute (P < .001). One patient (3.7%) was not satisfied and 18 patients (66.7%) were very satisfied (score of 4). Average satisfaction score was 3 (satisfied). CONCLUSIONS: Ciliary muscle contraction to restore accommodation was safe and improved the short-term accommodative ability of patients with early emmetropic presbyopia.
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ORIGINAL ARTICLE
resbyopia, from the Greek words presbys meaning
“old man” and ops meaning to “see like,” is the in-
ability to comfortably focus on close objects due to
aging. This is the most common physiologic alteration of eye-
sight, affecting more than 1.2 billion individuals worldwide,
and leads to a major impact on productivity among healthy
adults.1 Presbyopia also significantly affects quality of life in
both developed and developing countries.2 Unlike ametropic
defects or refractive errors (myopia, hyperopia, and astigma-
tism), caused by genetic and envi ronmental conditions that
affect the shape of the eye, presbyopia does affect virtually
every individual older than 50 or 60 years due to the progres-
sive loss of the accommodation ability of the eye.
Current treatments for presbyopia are based on optical cor-
rections, but surgical refractive modifications are also possible.
Although near vision can be easily recovered by the use of read-
ing glasses, there is nonetheless a great demand for more perma-
nent solutions to avoid the use of corrective lenses. However,
available invasive surgical procedures have several limitations
and are not devoid of side effects.3 Pharmaceutical treatments
stimulating the contraction of ciliary muscles in the presence of
different miotics4-6 and nonsteroidal anti-inflammatory drugs7
have been recently described, suggesting the relevance of the
stimulation of the ciliary muscle to recover some of its function.
P
ABSTRACT
PURPOSE: To report short-term results of pulsed ciliary
muscle electrostimulation to improve near vision, likely
through restoring accommodation in patients with em-
metropic presbyopia.
METHODS: In a prospective non-randomized trial, 27
patients from 40 to 51 years old were treated and
13 age- and refraction-matched individuals served as
untreated controls. All patients had emmetropia and
needed near sphere add between +0.75 and +1.50
diopters. The protocol included four sessions (one every
2 weeks within a 2-month period) of bilateral pulsed (2
sec on; 6 sec off) micro-electrostimulation with 26 mA
for 8 minutes, using a commercially available medical
device. The uncorrected distance visual acuity (UDVA)
(logMAR) for each eye, uncorrected near (40 cm) visual
acuity in each eye (UNVA) and with both eyes (UNVA OU)
(logMAR), and reading speed (number of words read per
minute at 40 cm) were measured preoperatively and 2
weeks after each session. Overall satisfaction (0 to 4
scale) was assessed 2 weeks after the last session.
RESULTS: UDVA did not change and no adverse events
were noted in either group. Bilateral and monocular
UNVA and reading speed were stable in the control
group, whereas they continuously improved in the
treated group (Friedman, P < .00001). Post-hoc sig-
nificant differences were found for monocular and bin-
ocular UNVA after the second treatment and after the
first treatment considering words read per minute (P <
.001). One patient (3.7%) was not satisfied and 18 pa-
tients (66.7%) were very satisfied (score of 4). Average
satisfaction score was 3 (satisfied).
CONCLUSIONS: Ciliary muscle contraction to restore
accommodation was safe and improved the short-term
accommodative ability of patients with early emme-
tropic presbyopia.
[J Refract Surg. 2017;33(9):578-583.]
From Diagnostica Oftalmologica e Microchirurgia Oculare, Rome, Italy
(LG, FG, VC, TF, MG); Sooft Italia SpA, Rome, Italy (DR); Rio de Janeiro
Corneal Tomography and Biomechanics Study Group, Instituto Olhos Renato
Ambrósio, Rio de Janeiro, Brazil (RA, MQS, BL); and Federal University of São
Paulo, São Paulo, Brazil (RA, MQS, BL).
Submitted: January 22, 2017; Accepted: May 26, 2017
Dr. Rusciano is a full-time employee of Sooft Italia, the company that com-
mercializes the electrostimulation device in Italy. The remaining authors have
no financial or proprietary interest in the materials presented herein.
The authors thank Dr. Federica Iannella, psychologist (University “La
Sapienza,” Rome, Italy), Dr. Carlo Leoni, psychologist (University “La
Sapienza,” Rome, Italy), and Professor Massimo Biondi, Director of Psychiatric
Department (University “La Sapienza,” Rome, Italy), for their contributions
elaborating the results of the Minnesota Test, and Dr. Antony Bridgewood
(University of Catania, Italy) for English proofreading of the manuscript.
Correspondence: Luca Gualdi, MD, Diagnostica Oftalmologica e Microchirurgia
Oculare, Via F. Civinini 111, 00197 Rome, Italy. E-mail: luca@gualdi.it
doi:10.3928/1081597X-20170621-05
Ciliary Muscle Electrostimulation to Restore
Accommodation in Patients With Early
Presbyopia: Preliminary Results
Luca Gualdi, MD; Federica Gualdi, MD; Dario Rusciano, PhD; Renato Ambrósio, Jr., MD, PhD;
Marcella Q. Salomão, MD; Bernardo Lopes, MD; Veronica Cappello, MD; Tatiana Fintina, MD;
Massimo Gualdi, MD
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Journal of Refractive Surgery • Vol. 33, No. 9, 2017
Ciliary Muscle Electrostimulation to Restore Accommodation/Gualdi et al
An alternative approach could address the revitalization
of the accommodation system by stimulating the ciliary
muscle to increase its potency so that it can overcome the
higher resistance of the system (ciliary muscle and lens)
that has become stiffer due to aging.8 Pulsed electrostim-
ulation is known to work for atrophic muscles9,10 and
therefore might also be effective on the ciliary muscle.11
We describe a non-invasive and innovative method to
improve near vision, likely through restoring the accom-
modation mechanism through pulsed micro-electrostim-
ulation of the anterior segment of the eye to stimulate
ciliary muscle contraction to restore accommodation.
PATIENTS AND METHODS
The study was conducted in accordance with the te-
nets of the 1964 Declaration of Helsinki, revised in 2000.
All patients signed an informed consent according to the
policies of the Associazione Italiana Medici Oculisti. In
a prospective non-randomized trial, 27 patients from 40
to 51 years old were treated and 13 individuals matched
for age and refraction served as untreated controls. All
patients had emmetropia with an uncorrected distance
visual acuity (UDVA) of 20/20 (0.0 logMAR) or better
and needed near sphere add between +0.75 and +1.50
diopters (D). Manifest refraction in both groups did not
change UDVA with any spherical or cylindrical addi-
tion; all patients had visual acuity of 20/20 or better and
a spherical equivalent of ±0.25 D or less (as measured by
the autorefractometer). Based on these data, cycloplegic
refraction was performed only on 5 patients at random
(to avoid the discomfort caused by this procedure to the
rest of the patients), and the resulting spherical equiva-
lent was found to be not more than +0.375 D.
Exclusion criteria included any ocular pathology, in-
cluding demyelinating and vascular diseases that may
reduce blood perfusion of the ciliary body, and epilepsy.
Patients who had a pacemaker were also excluded be-
cause of possible electrical interactions. In addition, pa-
tients receiving specific treatments that could possibly
influence accommodation, such as antidepressant, anti-
spasmodic, antihistaminic, and diuretic drugs, were also
excluded. To exclude patients with obvious psychologi-
cal problems, all of those enrolled had to complete the
psychological Minnesota Test questionnaire (MMPI-2),
consisting of 567 questions to which a true or false an-
swer has to be given. The results were elaborated by the
Psychology Department of the University “La Sapienza”
in Rome, Italy. Enrolled patients were advised about the
possible advantages and limitations of the procedure.
The protocol, established after previous experience, in-
cluded four sessions of bilateral pulsed (2 sec on; 6 sec off)
micro-electrostimulation with 26 mA for 8 minutes, with
2-week intervals, using the Ocufit medical device (Sooft;
Montegiorgio, Italy) consisting of special lenses and a cali-
brated power supply to which the lenses have to be con-
nected (see below). Micro-electrostimulation treatments
were performed by the first author (LG) at the Diagnostica
Oftalmologica e Microchirurgia Oculare clinic in Rome,
Italy. Two drops of 0.4% oxybuprocaine were instilled
before treatment with the patient in the supine position.
A 20-mm polycarbonate scleral contact lens equipped
with four microelectrodes at the four cardinal points po-
sitioned 3.5 mm outside the limbal area corresponding to
the ciliary body region (Figure A and Video 1, available
in the online version of this article) was used. The micro-
electrodes were connected through four electric pins and
cables to the electrical generator (Figures AA-AC). The
lens was carefully applied onto the eye (Figure AD) to
avoid trauma to the ocular surface. The electrostimula-
tor (Sooft) generates biphasic compensated square waves
for a low voltage micro-electrostimulation of the ciliary
muscle. The amount of electrical current flowing from
the positive to the negative pole remained stable, and
any risk of thermal damage was prevented. During the
8 minutes of treatment, 60 cycles of electrostimulation
were given, with each cycle consisting of 2 seconds of
electrical impulse and 6 seconds of rest (Figure AE).
After each treatment, two drops of an antibiotic-steroid
were instilled in each treated eye to prevent postopera-
tive inflammation or infection. No other medications
were needed. Although both eyes could be treated si-
multaneously, treatments were generally performed in
one eye with immediate sequential treatment of the fel-
low eye. The ciliary muscle contraction to restore ac-
commodation didactic demonstration of the procedure
is available online (https://youtu.be/724pb1Kyp80).
Clinical examinations were performed 1 hour pri-
or to the ciliary muscle contraction to restore accom-
modation treatment and 2 weeks after each treatment
(just before starting the next one). Because the proto-
col included four sessions, the last examination was
approximately 2 weeks after the fourth treatment (or 2
months after enrollment). LogMAR UDVA for each eye,
logMAR uncorrected near (40 cm) visual acuity in each
eye (UNVA) and in both eyes (UNVA OU), and reading
speed (number of words read per minute at 40 cm) were
taken preoperatively and 2 weeks after each session.
UNVA was measured on standard MNREAD charts at a
fixed distance of 40 cm, under standard (500 lux) illu-
mination and no extra lighting. Reading speed was mea-
sured by two orthoptists, one holding a chronometer
and the other counting the words, under standard room
illumination on MNREAD charts at 40 cm distance.
Objective variations of the accommodation system
were measured (only in one eye randomly chosen from
7 patients) by ultrasound biomicroscopy (Optikon, Rome,
580 Copyright © SLACK Incorporated
Ciliary Muscle Electrostimulation to Restore Accommodation/Gualdi et al
Italy), which was recorded under standard illumination
with the patient in the supine position after the instilla-
tion of two drops of anesthetic (oxybuprocaine) 2 minutes
before the examination. Three good quality images were
recorded for far vision (with the eye focused on infinity,
with the lens in the relaxed position) and three for near vi-
sion (with the eye focused on a near point at 30 cm, with
the lens at the maximum accommodation and thickness).
Overall satisfaction (0 to 4 scale, where 0 is no
satisfaction and 4 is high satisfaction) was assessed
2 weeks after the last session, at the time of the last
clinical examination.
StatiStical analySiS
Statistical analyses were performed by different soft-
ware packages: MedCalc Statistical Software (version
16.8.4; MedCalc, Ostend, Belgium: https://www.medcalc.
org) and the R Core Team (version 3.3.1.2016; R Founda-
tion for Statistical Computing, Vienna, Austria: https://
www.R-project.org). The non-parametric Friedman test
was used for testing the differences between the several
time points for the same patients for each outcome vari-
able analyzed. If the null-hypothesis was rejected with
a P value of less than .001, pairwise post-hoc analysis
was conducted based on Conover’s method.12 Because
the Friedman test is for related samples, all cases had no
missing observations for the analyzed variables.
RESULTS
Among the 27 treated patients, 17 (63%) were wom-
en. The average patient age was 45.74 ± 3.35 years
(range: 40 to 51 years). The control group of 13 indi-
viduals had 7 women (53.84%) and the average age
was 45.8 ± 3.1 years (range: 40 to 49 years).
Three of the 27 treated patients (11.11%) reported a dry
eye sensation soon after treatment, which was completely
resolved in 48 hours by using artificial tears containing hy-
aluronic acid. No other side effects were observed.
Table 1, Tables A-B (available in the online version
of this article), and Figures 1-3 include the data values
and their graphic illustration of UNVA, UNVA OU)
and reading speed defined earlier. UNVA improved
after the second treatment compared to preoperative
values, whereas reading speed was significantly im-
proved soon after the first treatment. Considering the
UNVA for each eye, there was a continuous improve-
ment. UNVA OU was better than in separated eyes,
which shows the improvement due to binocularity.
An ultrasound biomicroscopy study was done on 7
eyes randomly chosen from 7 treated patients to obtain
a quantitative and objective measurement of the change
occurring during accommodation soon after electro-
stimulation training. The measurement was taken in the
supine position with both eyes open and one eye had
the ultrasound biomicroscopy immersion measurement
taken with the patient looking at distance and to the close
target. The lens curvature and thickness were recorded
at its maximum convexity, showing an average increase
of +0.07 mm (range: 4.10 to 4.17 mm) of the lens thick-
ness, a decrease of the anterior lens curvature of -0.24
mm (range: 6.96 to 6.72 mm), and a decrease of the poste-
rior lens curvature of -0.08 mm (range: 4.60 to 4.52 mm).
Figure 4 shows a representative picture of this analysis.
None of the clinical parameters were altered (P >
.10) in the control group at the time of their enroll-
ment, and all remained stable over the corresponding
time of observation.
A subjective questionnaire was given to treated pa-
tients to record their satisfaction 2 weeks after the end
of the fourth treatment cycle, at the time of the last
assessment. Most (96.3%) stated that they were satis-
fied and felt a real improvement in their visual abil-
ity (highly improved = 10, improved = 8, slightly im-
proved = 8, not improved = 1).
DISCUSSION
This is the first clinical report of the results of
pulsed ciliary muscle contraction to restore accommo-
dation. Although we have reported short-term results
(up to 2 months), our findings support ciliary muscle
contraction to restore accommodation as a promising
treatment for presbyopia.
TABLE 1
LogMAR UNVA (Smallest Character) Data Measured by
MNREAD Charts at 40 cm Distance
UNVA Minimum 25th Percentile Median 75th Percentile Maximum
Preop -0.1 0.025 0.12 0.23 0.36
T1 -0.12 0.01 0.1 0.2 0.31
T2 -0.2 0.025 0.1 0.18 0.29
T3 -0.19 0.02 0.09 0.16 0.34
T4 -0.2 0 0.08 0.12 0.24
UNVA = uncorrected near visual acuity; preop = preoperative
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Journal of Refractive Surgery • Vol. 33, No. 9, 2017
Ciliary Muscle Electrostimulation to Restore Accommodation/Gualdi et al
The complete pathophysiology of presbyopia remains
poorly understood. Donders (1864) proposed that presby-
opia is caused by a decrease in the force of contraction
of the ciliary muscle with age and Helmholtz (1855) sug-
gested that the lens becomes more difficult to deform with
age due to lenticular sclerosis.13 According to the latter
theory, accommodation occurs as a result of the elastic
properties of the lens and possibly the vitreous, which al-
low the lens to expand and increase its power when zonu-
lar tension is relieved during ciliary muscle contraction.14
As the lens changes with age, the ability to expand and in-
crease its refractive power is progressively lost. Possibly,
a combination of these two mechanisms determines the
evolution and natural course of presbyopia. Interestingly,
Helmholtz’s theory of sclerosis of the crystalline lens as
the cause of presbyopia was challenged by Schachar,15
who suggested that when the longitudinal muscle fibers
of the ciliary muscle contract during accommodation,
they place more tension on the equatorial zonules while
relaxing the anterior and posterior zonules. This force dis-
tribution causes an increase in the equatorial diameter of
the lens, decreasing the peripheral volume while increas-
ing the central volume. As the central volume increases,
so does the power of the lens. According to Schachar’s
theory, presbyopia occurs because of the increasing equa-
torial diameter of the aging lens. Once the lens diameter
reaches a critical size, usually during the fifth decade of
life, the ability of the ciliary muscle to provide resting ten-
sion on the zonules is significantly reduced.
Although there are several approaches to manage the
visual disability associated with presbyopia, most of the
currently available treatments are compensatory optical
tools rather than corrective, involving more pseudo-
accommodation rather than true accommodation. Meth-
ods used so far for the correction of presbyopia include
contact lenses and spectacles, whereas the surgical cor-
rection of presbyopia remains a challenge for refractive
surgeons.16 Pharmacological attempts to counteract pres-
byopia also exist. They are focused on relieving lens rigid-
ity (eg, eye drops containing lipoic acid17) or enhancing
iris and ciliary muscle contractility (with a combination
of one parasympathetic agent, one NSAID, two alpha-
agonists agents, and one anticholinesterase agent).6
Accommodation occurs by the contraction (forward
and inward movement) of the ciliary muscle and relax-
ation of the zonular fibers, resulting in lens thickening
and steepening with consequent increase in the conver-
gence refractive power of the eye.18 Therefore, age-related
changes in each component of the accommodative ap-
paratus (either separately or combined) have been impli-
cated in the pathophysiology of presbyopia, including
lens hardening19 and posterior restriction of the ciliary
Figure 1. Dot-plot with superimposed box plot of the logMAR uncorrected
near visual acuity (UNVA) (smallest character) measured by MNREAD
charts at 40 cm distance at the different time points, along with the
pairwise post-hoc significant differences. ***P < .001.
Figure 2. Dot-plot with superimposed box plot of the logMAR uncorrected
near visual acuity (smallest character) with both eyes (UNVA OU) measured
by MNREAD charts at 40 cm distance at the different time points, along
with the pairwise post-hoc significant differences. ***P < .001.
Figure 3. Dot-plot with superimposed box plot of the reading velocity mea-
sured as the number of words read per minute at the different time points,
along with the pairwise post-hoc significant differences. ***P < .001.
582 Copyright © SLACK Incorporated
Ciliary Muscle Electrostimulation to Restore Accommodation/Gualdi et al
muscle.20 Crystalline lens weight progressively increases
with aging due to the gradual loss of water content and
the increase of glycoproteins such as albumin and electro-
lytes such as calcium and potassium.21 Moreover, there
is an increment of disulfide bonding, oxidation of me-
thionine, and deamination and degradation of glutamine
and asparagine leading to protein backbone cleavage.
The consequence is lens stiffening with a progressive de-
crease of the refractive power during accommodation.22
Therefore, considering the ciliary muscle as the engine of
the accommodative process, and because its magnitude
of forward centrally and inward movement is reduced
with increasing age,23,24 an alternative approach for pres-
byopia might be to address its revitalization.
Our hypothesis is that ciliary muscle contraction to
restore accommodation addresses such an active part of
the accommodation system by working out the ciliary
muscle to increase its potency, so that it can overcome
the higher resistance of the system that has become stiffer
due to aging. This approach is already known to work for
atrophic muscles9,10 and might also work on the ciliary
muscle. If this hypothesis is correct, then the contraction
of the ciliary muscle is expected to stretch the tendinous
formation in direct contact with the sclerocorneal trabec-
ulate, thus increasing the distance between the lamellae
of the sclerocorneal angle. In this way, it could also re-
store the natural function of the trabeculate in aged pa-
tients, thus reducing their intraocular pressure.25,26 Ac-
cordingly, electrostimulation was found to be effective
in decreasing intraocular pressure in patients affected by
ocular hypertension and glaucoma.11,27
However, based on recent evidence,28,29 the question
remains as to how ciliary muscle contraction to restore
accommodation partially restores “true physiological
accommodation” differently from other more invasive
procedures, which create some form of “pseudoaccom-
modation” or other corneal or lenticular aberrations.
This may be the subject of further research, likely also
based on different evaluation methods.30
The data presented demonstrate that electrostimula-
tion is effective in improving near vision ability in pa-
tients with early presbyopic emmetropia, which is likely
related to restoring the accommodation process because
the data suggest that ciliary muscle contraction to re-
store accommodation enhances the ability of the ciliary
muscle to contract and thereby perform accommodation.
Electrostimulation works like training in physiotherapy,
so that the best results are expected for young presbyopic
patients (40 to 50 years), when the ciliary muscle starts
needing more strength to move a stiffer and bigger lens.
Also, there should be an age limit for the efficiency of
such treatment. Interestingly, because presbyopia is con-
sidered a preliminary stage prior to age-related cataract,31
in a continuum process described as “dysfunctional lens
syndrome,” ciliary muscle contraction to restore accom-
modation could be associated with other treatments that
aim to reverse the lens aging process, which leads to
presbyopia and is also associated with ocular hyperten-
sion and possibly cataract formation.
Because ciliary muscle contraction to restore accom-
modation is a passive exercise, the effect of electrostimu-
lation is expected to last for a limited time period and
then progressively regress. To maintain the benefit, it is
necessary to periodically repeat the treatment, which re-
quires developing customized programs based on the in-
dividual response related to the observed effect. Patient
Figure 4. Example of preoperative (left) and postoperative (right) ultrasound biomicroscopy scan taken under accommodation showing an increased
lens thickness (L) (+0.10 mm), a decreased anterior (Ra) and posterior (Rp) ray of curvature of the lens (-0.16 and -0.08 mm) resulting in improved
accommodative response after the micro-electrostimulation of the ciliary muscle treatment.
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Journal of Refractive Surgery • Vol. 33, No. 9, 2017
Ciliary Muscle Electrostimulation to Restore Accommodation/Gualdi et al
education is fundamental to ensure realistic expecta-
tions, but also challenging. Further studies are under way
in our clinic (and several others) to optimize the elec-
trostimulation parameters (time, voltage, and device) to
improve such results. Moreover, it is possible that novel
approaches may play a synergistic role in ciliary muscle
contraction to restore accommodation such as pharmaco-
logic treatments with lipoic acid17,32 or N-acetylcarnosine
eye drops33 that appear to work by restoring lens elastic-
ity and preventing age-related changes.
AUTHOR CONTRIBUTIONS
Study concept and design (LG, FG, RA, VC, MG); data collection
(LG, DR, TF); analysis and interpretation of data (LG, DR, RA, MQS,
BL, TF); writing the manuscript (LG, DR, RA); critical revision of the
manuscript (LG, FG, DR, RA, MQS, BL, VC, TF, MG); statistical ex-
pertise (RA, BL); administrative, technical, or material support (LG,
TF); supervision (LG, FG, VC, MG)
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29. Croft MA, Nork TM, McDonald JP, Katz A, Lütjen-Drecoll E,
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Figure A. Illustration of the medical device for the electrostimulation of the ciliary muscle. (A) Bottom side of the
lens showing the four electrode contacts. (B) Upper side of the lens showing the four cables to be connected to the
power generator. (C) Positioning of the lenses on the ocular surface of a patient. (D) Power supply during a bilateral
simultaneous treatment in which two scleral contact lenses in polycarbonate are stabilized by two syringes creat-
ing a vacuum and connected by cables directly to the Ocufit (Sooft; Montegiorgio, Italy) electrostimulator medical
device. (E) Pulse trains are in the form of compensated biphasic square-waves. The graph illustrates treatment cycle
sequences consisting in pulsed repetitions of 2 seconds of electrical impulse followed by 6 seconds of rest.
TABLE A
Binocular UNVA (Smallest Character) Data Measured by
MNREAD Charts at 40 cm Distance
Time Minimum 25th Percentile Median 75th Percentile Maximum
Preop -0.2 0.0175 0.1 0.223 0.33
T1 -0.2 0.01 0.1 0.18 0.3
T2 -0.25 0.0025 0.05 0.11 0.23
T3 -0.2 0 0.02 0.1 0.31
T4 -0.2 -0.075 0.02 0.1 0.21
UNVA = uncorrected near visual acuity; preop = preoperative
TABLE B
No. of Words Read per Minute at 40 cm Distance
Time Minimum 25th Percentile Median 75th Percentile Maximum
Preop 76 116 142 161.25 261
T1 103 137.75 162 188.75 262
T2 106 152.75 176 212.75 269
T3 131 165.75 180 228 284
T4 140 178.5 203 217.75 284
preop = preoperative
... 4,5 These signals should include the needed focus direction whether positive or negative. 6,7 The human eye has a maximum capacity of accommodation, known as accommodative amplitude (AA), which depends mainly on age. Ametropia is a potential factor influencing AA but studies have produced conflicting results. ...
... Some studies have reported greater AA in myopes than in emmetropes and hyperopes, while others found the opposite or no differences. 5,6 Although most studies show that AA is larger in myopic eyes, results are not fully comparable because of differences in methodologies between studies. Different choices of reference plane for specifying vergence of the far and near points are of importance for our investigation of potential optical explanations for variability in results reported in the literature. ...
Article
Background: To study whether the range of accommodation differs in myopes and hypermetropes than normal population. Purpose: To study the range of accommodation in myopes and hypermetropes in comparison to normal population in different age groups. Materials and methods: A comparative cross-sectional study was conducted at MHL from January 2018 to October 2018. Total 99 patients were enrolled in this study who had refractive errors. All patients were included who had 10 – 55 years age. Both genders were included. Both myopic and hypermetropic patients were included having fully corrected myopia and hypermetropia. Patients with any ocular pathologies were excluded. All patients who were included in this study had complete ocular and posterior chamber examination from ophthalmologist. There visual acuity was recorded using Snellen`s visual acuity chart and recorded in Snellen notation. Near vision was assessed on near vision chart. Then range of accommodation will be measured by RAF meter. All data entered and analyzed by SPSS 20 (Statically package for social scientist). Bar charts and Pie charts were used to describe qualitative data and range, mean, S.Dwere used to express quantitative data. For data normality Kolmogorov-Smirnov and Shapiro Wilktest used and showed that all parameters are non-parametric as p value is ≤ 0.05 (p = 0.000). Results: Total 99individuals were analyzed who had refractive errors. There were 60 female and 39male individuals. Avg age of individuals was 21 with standard deviation ±3. Association of rang of accommodation between hypermetropes and emmetropes during point break, Rec point and Rang D the p value is 0.001 in all points. Association of rang of accommodation between emmetropes and myopes during point break, Rec point and Rang D the p value is 0.142, 0.224 and 0.315 accordingly. Conclusion: Association of rang of accommodation is significant between emmetropes and hypermetropes (p=0.001). But there is no significant association of rang of accommodation between Myopes and emmetropes (p=0.224).
... The prevalence of LUTS in men in general varies from 64% to 72% [3]. Presbyopia, defined as age-related impairment in near vision due to the progressive loss of the accommodative ability of the eye is common and affects virtually every individual older than 50 to 60 years [4][5][6]. In one study, an estimated 1.8 billion cases of presbyopia were reported worldwide in 2015 [7]. ...
... Rasch scale (score, 0-100) b) 54.7 ± 9.9 57.0 (48.9-61. 6 ...
Article
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Purpose: The objective of this study was to investigate the change in near visual function after the administration of oral silodosin to patients with lower urinary tract symptom (LUTS). Methods: This prospective study included treatment naïve patients who were scheduled to start treatment with silodosin for LUTS. A comprehensive ophthalmological evaluation including the near vision and the automated pupillometry was performed at baseline and after 3 months of silodosin treatment. For subjective assessment of near visual ability and satisfaction, a Near Activity Visual Questionnaire-10 (NAVQ-10) was also used at the same time (higher scores indicating worse quality). Results: Of 23 patients enrolled in this study, 15 continued with silodosin (8mg once daily) treatment for 3 months and completed a follow-up evaluation. The mean age of participants was 60.4±8.4 years. Distant visual acuity and spherical error were unchanged after silodosin treatment. However, near vision acuity (logMAR) was improved after treatment (right, 0.47±0.36 vs. 0.38±0.39, p=0.018; left, 0.41±0.37 vs. 0.31±0.34, p=0.068; both, 0.27±0.26 vs. 0.21±0.27, p=0.043). Pupil size under room light decreased significantly in both eyes (right, 3.77±0.60 vs. 3.16±0.58, p=0.001; left, 3.72±0.80 vs. 3.21±0.75, p=0.002). The Rasch scale at NAVQ-10 improved from 54.7±9.9 to 48.5±11.2 (p=0.004). Conclusions: This preliminary study demonstrated that highly selective alpha-1A adrenergic receptor antagonists such as silodosin improve near visual acuity and quality in patients with LUTS/BPH. Decrease in pupil size caused by inhibition of adrenergic alpha 1 mediated contraction of iris dilator muscle is a possible mechanism underlying improved near vision.
... Presbyopia and its impact on visual impairment, particularly in countries such as China, 1 is increasing due to population ageing. 2 Presbyopia is more than just near visual loss or a functional decline in the crystalline lens' ability to accommodate. As presbyopia is derived from Ancient Greek πρέσβυς translated into Latin (présbus, 'old man') and ὤψ (ṓps, 'eye' or to 'see like'), 3 a definition, centred on the patient's functional experience to fit this etymology has been proposed. Here, 'presbyopia occurs when the physiologically normal age-related reduction in the eyes focusing range reaches a point, when optimally corrected for distance vision, that the clarity and comfort of vision at near is insufficient to satisfy an individual's requirements'. 4 The definition acknowledges that presbyopia is defined by the impact of the tasks that an individual conducts rather than physiological ocular changes in isolation. ...
Article
Full-text available
Presbyopia occurs when the physiologically normal age-related reduction in the eyes focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual’s requirements. Hence, it is more about the impact it has on an individual’s visual ability to function in their environment to maintain their lifestyle than a measured loss of focusing ability. Presbyopia has a significant impact on an individual’s quality of life and emotional state. While a range of amelioration strategies exist, they are often difficult to access in the developing world and prescribing is generally not optimal even in developed countries. This review identified the need for a standardised definition of presbyopia to be adopted. An appropriate battery of tests should be applied in evaluating presbyopic management options and the results of clinical trials should be published (even if unsuccessful) to accelerate the provision of better outcomes for presbyopes.
... But this way might be expensive and intractable which is an invasive procedure (35)(36)(37)(38)(39)(40). Other options such as pharmacological therapies and ciliary muscle electrostimulation have not been widely applied in clinics yet (41,42). Generally, obtaining spectacles is vital for the uncorrected presbyopia population, which was reported to be relative low cost (minimum price of a pair of spectacles: 8.6 to 12.9 US $) in previous studies (7,43,44). ...
Article
Full-text available
Objective To estimate the burden of potential productivity losses due to uncorrected and under-corrected presbyopia in LMICs among the working-age population in both the cross-sectional and longitudinal manner. Methods We extracted data for the prevalence of presbyopia from the Global Burden of Diseases (GBD), Injuries, and Risk Factors Study 2019. Data for the gross domestic product (GDP) per capita were extracted from the World Bank database and Central Intelligence Agency's World Factbook. We introduced life table models to construct age cohorts (in 5-year age groups) of the working-age population (aged from 40 to 64 years old) in LMICs, with simulated follow-up until 65 years old in people with and without uncorrected presbyopia. The differences in productivity-adjusted life years (PALYs) lived and productivity between these two cohorts were calculated. The potential productivity loss was estimated based on GDP per capita. The WHO standard 3% annual discount rate was applied to all years of life and PALYs lived. Results In 2019, there were 238.40 million (95% confidence interval [CI]: 150.92–346.78 million) uncorrected and under-corrected presbyopia cases in LMICs, resulting in 54.13 billion (current US dollars) (95% confidence interval [CI]: 34.34–79.02 billion) potential productivity losses. With simulated follow-up until retirement, those with uncorrected and under-corrected presbyopia were predicted to experience an additional loss of 155 million PALYs (an average loss of 0.7 PALYs per case), which was equivalent to a total loss of US$ 315 billion (an average loss of US$ 1453.72 per person). Conclusions Our findings highlight the considerable productivity losses due to uncorrected and under-corrected presbyopia in LMICs, especially in a longitudinal manner. There is a great need for the development of enabling eye care policies and programs to create access to eye care services, and more healthcare investment in the correction of presbyopia in the working-age population in LMICs. This study could provide evidences for some potential health-related strategies for socio-economic development.
... Предложен ряд методик для электростимуляции цилиарной мышцы с целью увеличения запаса аккомодации, для восстановления аккомодации при ранней пресбиопии и для лечения прочих нарушений аккомодации. При лечении пациентов с пресбиопией в 96,3 % случаев отмечали улучшение остроты зрения и снижение астенопических жалоб [28][29][30]. ...
Article
The review discusses the treatment methods based on physical phenomena in clinical ophthalmology. The physical nature and treatment techniques using electric current and electromagnetic field, light and laser radiation, mechanical energy and sound waves, high and low temperature in various ocular pathologies are considered. It is noted that reliable evaluation of the effectiveness of physical treatment methods for the different diseases and pathological conditions requires the implementation of protocols that include objective testing methods of the structure and functioning of the visual system. Once the clinical effectiveness of the particular physical treatment methods and techniques is confirmed, further development and improvement of the most efficient ones becomes possible.
... 24 Electrostimulation is a nonpharmaceutical approach for reviving ciliary muscle contraction. 25 Laser options include scleral laser micro-excision, in which an Er:YAG laser is applied to increase plasticity and compliance of the scleral tissue to facilitate contraction of the ciliary muscles, and femtosecond laser manipulation of the lens to increase its deformability, and thus accommodative ability. 26,27 Other surgical options include implants which increase the area between the ciliary muscle and the sclera to restore accommodation. ...
Article
Full-text available
Daniel H Chang,1 George O Waring 4th,2 Milton Hom,3 Melissa Barnett4 1Empire Eye and Laser Center, Bakersfield, CA, USA; 2Waring Vision Institute, Mt. Pleasant, SC, USA; 3Canyon City Eyecare, Azusa, CA, USA; 4University of California, Davis Eye Center, Sacramento, CA, USACorrespondence: Daniel H ChangEmpire Eye and Laser Center, 4105 Empire Drive, Bakersfield, CA, 93309, USAEmail dchang@empireeyeandlaser.comAbstract: Presbyopia, a loss of accommodative ability associated with aging, is a significant cause of vision impairment globally. At the clinical level, it is a frustrating and difficult issue that negatively impacts patients’ quality of life. Less appreciated is the fact that loss of accommodative ability and its current treatments methods may present safety concerns, for example, increasing the risk of falls. Therefore, a more complete understanding of treatment options with respect to how they relate to the natural ability of the eye is needed to improve decision making and to aid clinicians in individualizing treatment options. This article reviews the options for expanding functional through focus—a term coined to describe the ability of the eye to see at all distances with minimal latency—by how they vary the refractive power over time, across the visual field, between eyes, or across a range of distances.Keywords: accommodation, presbyopia, functional through focus
Article
Accommodation is the change in dioptric power of the eye. It is a dynamic process that allows focusing on an object at all distances. In order to focus sharply, three physiological responses, known as the triad of accommodation, are produced by a change in pupil size, a change in shape and position of the lens, and ocular convergence. This is modulated by the autonomic nervous system, mainly the parasympathetic nervous system. Presbyopia is a refractive condition that occurs with aging, usually manifesting around 40–50 years of age, and is a result of the loss of accommodation in the eye, causing loss of visual performance when focusing on objects placed at different distances, starting with near vision. Glasses, contact lenses, surgical approaches and now pharmacological treatments are accepted methods of treating presbyopia. Pharmacological treatment is a promising new noninvasive option for treating presbyopia. Currently there are three pharmacological approaches to the treatment of presbyopia. The first one aims to produce miosis and, from a pinhole effect, increase depth of focus, and therefore improve uncorrected near visual acuity (UNVA). The second one addresses rehabilitating accommodation in a binocular way, allowing good vision at all distances. Finally, the third strategy uses lipoic acid to restore the lost elasticity of the lens. All of these pharmacological treatments are topical non-invasive eyedrops, with no serious adverse effects having been reported with any of the strategies, and require the right patient selection process to fulfill expectations and needs. The aim of this article is to provide an update on recent advances in this field.
Article
Purpose of review: Presbyopia is the normal progressive loss of accommodation, which leads to the inability to focus clearly on objects located at different distances. Some of the accepted methods for treating this condition are glasses, contact lenses, and surgery. Pharmacological treatments are a new and promising noninvasive option for dealing with presbyopia. The aim of this review is to provide an update on some recent advances in this field. Recent findings: Currently, there are three different strategies for the pharmacological treatment of presbyopia. The first one aims to produce miosis and increase depth of focus through a pinhole effect, therefore improving uncorrected near visual acuity. The second one tries to restore the elasticity the lens has lost due to aging. Finally, the third strategy is based on rehabilitating accommodation; which is to say, in a binocular way, allowing for good vision at all distances. Summary: Pharmacological treatments are a new alternative that expands the diversity of existing strategies for treating presbyopia. These treatments are based on the instillation of eyedrops with different compositions, which vary according to the different strategies. Many of these developments will most likely be on the market in the next few years. If the process of patient selection is done properly, any one of these three strategies can be used successfully.
Article
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Background To test and compare in a masked fashion the efficacy of using a parasympathomimetic drug (3% carbachol) and an alpha-2 agonist (0.2% brimonidine) in both combined and separate forms to create optically beneficial miosis to pharmacologically improve vision in presbyopia. MethodsA prospective, double-masked, randomized, controlled clinical trial was conducted. Ten naturally emmetropic and presbyopic subjects between 42 and 58 years old with uncorrected distance visual acuity of at least 20/20 in both eyes without additional ocular pathology were eligible for inclusion. All subjects received 3% carbachol and 0.2% brimonidine in both combined and separate forms, 3% carbachol alone and 0.2% brimonidine (control) alone in their non-dominant eye in a crossover manner with one week washout between tests. The subjects’ pupil sizes and both near and distance visual acuities will be evaluated pre- and post-treatment at 1, 2, 4, and 8 h, by a masked examiner at the same room illumination. ResultsStatistically significant improvement in mean near visual acuity (NVA) was achieved in all subjects who received combined 3% carbachol and 0.2% brimonidine in the same formula compared with those who received separate forms or carbachol alone or brimonidine alone (P < 0.0001). Conclusion Based on the data, the combined solution demonstrated greater efficacy than the other solutions that were tested. Improving the depth of focus by making the pupil small caused statistically significant improvement in near visual acuity, with no change in binocular distance vision. Trial registrationACTRN12616001565437. Registered 11 November 2016.
Article
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Purpose: The purpose of the experiments described here was to determine the effects of lipoic acid (LA)-dependent disulfide reduction on mouse lens elasticity, to synthesize the choline ester of LA (LACE), and to characterize the effects of topical ocular doses of LACE on mouse lens elasticity. Methods: Eight-month-old mouse lenses (C57BL/6J) were incubated for 12 hours in medium supplemented with selected levels (0-500 μM) of LA. Lens elasticity was measured using the coverslip method. After the elasticity measurements, P-SH and PSSP levels were determined in homogenates by differential alkylation before and after alkylation. Choline ester of LA was synthesized and characterized by mass spectrometry and HPLC. Eight-month-old C57BL/6J mice were treated with 2.5 μL of a formulation of 5% LACE three times per day at 8-hour intervals in the right eye (OD) for 5 weeks. After the final treatment, lenses were removed and placed in a cuvette containing buffer. Elasticity was determined with a computer-controlled instrument that provided Z-stage upward movements in 1-μm increments with concomitant force measurements with a Harvard Apparatus F10 isometric force transducer. The elasticity of lenses from 8-week-old C57BL/6J mice was determined for comparison. Results: Lipoic acid treatment led to a concentration-dependent decrease in lens protein disulfides concurrent with an increase in lens elasticity. The structure and purity of newly synthesized LACE was confirmed. Aqueous humor concentrations of LA were higher in eyes of mice following topical ocular treatment with LACE than in mice following topical ocular treatment with LA. The lenses of the treated eyes of the old mice were more elastic than the lenses of untreated eyes (i.e., the relative force required for similar Z displacements was higher in the lenses of untreated eyes). In most instances, the lenses of the treated eyes were even more elastic than the lenses of the 8-week-old mice. Conclusions: As the elasticity of the human lens decreases with age, humans lose the ability to accommodate. The results, briefly described in this abstract, suggest a topical ocular treatment to increase lens elasticity through reduction of disulfides to restore accommodative amplitude.
Article
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PurposeThe feasibility, in terms of safety and potential efficacy, of a new drug combination for binocular use as a noninvasive pharmacological solution for treating presbyopia was examined. Methods Fourteen emmetropic presbyopic subjects (28 eyes) were given one drop of the preparation under study in each eye. For each patient, the uncorrected distance visual acuity, uncorrected near visual acuity, near and far refraction, best corrected visual acuity, best corrected far-near visual acuity, photopic and scotopic pupil size, Schirmer’s test, endothelial cell count, intraocular pressure, keratometry, pachymetry, and anterior chamber depth were all performed or assessed prior to the administration of the eye drops and then 0.5, 1, 2, 3, 4, and 5 h, 1 week, and 1 month post-administration prospectively in each eye and binocularly. ResultsThe results showed that near uncorrected visual acuity improved by about 2–3 lines from baseline in each eye and binocularly. There was no degradation in uncorrected far vision in each eye and binocularly in any patient. Refractive measurements performed in this study showed there was a maximum myopic shift of just 0.5 D that progressively reduced and disappeared at 4 h. Conclusion The new topical drug treatment analyzed herein significantly improved near vision without affecting far vision. This binocular pharmacologic treatment of presbyopia has the potential to ameliorate the reading vision of presbyopes and possesses the advantages of a nonmonovision therapy. A randomized, controlled, double-masked clinical trial with a twice-a-day treatment schedule is ongoing at our institution. FundingThis study was supported in part by the Spanish Ministry of Health, Instituto Carlos III, Red Temática de Investigación Oftalmológica (OFTALRED), and Fundación Oftalmológica Vejarano (Popayán, Colombia).
Patent
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A method of for prevention of presbyopia and glaucoma envisages stimulation of the ciliary body to determine contraction thereof via a low-voltage d.c. current sent in the form of pulse trains. This contraction, if applied in a rhythmic way at a constant frequency, subjects the ciliary muscle to a passive gymnastics increasing the force of contraction thereof, the dimensions, and the efficiency. This increase of force enables the crystalline to be moved with greater efficiency and consequently increases the power of accommodation thereof. The contraction of the ciliary muscle stretches the tendinous formation in direct contact with the sclero-corneal trabeculate and increases the distance between the lamellae of the sclero-corneal angle, restoring the natural function of the trabeculate and thus preventing glaucoma. Stimulation of the anatomical area corresponding to the ciliary body occurs through the use of conductive electrodes positioned in direct contact with the bulbar conjunctiva at an appropriate distance from the corneal limbus.
Article
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The onset of presbyopia in middle adulthood results in potential losses in productivity among otherwise healthy adults if uncorrected or undercorrected. The economic burden could be significant in lower-income countries, where up to 94% of cases may be uncorrected or undercorrected. This study estimates the global burden of potential productivity lost because of uncorrected functional presbyopia. Population data from the US Census Bureau were combined with the estimated presbyopia prevalence, age of onset, employment rate, gross domestic product (GDP) per capita in current US dollars, and near vision impairment disability weights from the Global Burden of Disease 2010 study to estimate the global loss of productivity from uncorrected and undercorrected presbyopia in each country in 2011. To allow comparison with earlier work, we also calculated the loss with the conservative assumption that the contribution to productivity extends only up to 50 years of age. The economic modeling did not require the use of subjects. We estimated the number of cases of uncorrected or undercorrected presbyopia in each country among the working-age population. The number of working-age cases was multiplied by the labor force participation rate, the employment rate, a disability weight, and the GDP per capita to estimate the potential loss of GDP due to presbyopia. The outcome being measured is the lost productivity in 2011 US dollars resulting from uncorrected or undercorrected presbyopia. There were an estimated 1.272 billion cases of presbyopia worldwide in 2011. A total of 244 million cases, uncorrected or undercorrected among people aged <50 years, were associated with a potential productivity loss of US $11.023 billion (0.016% of global GDP). If all those people aged <65 years are assumed to be productive, the potential productivity loss would be US $25.367 billion or 0.037% of global GDP. Correcting presbyopia to the level achieved in Europe would reduce the burden to US $1.390 billion (0.002% of global GDP). Even with conservative assumptions regarding the productive population, presbyopia is a significant burden on productivity, and correction would have a significant impact on productivity in lower-income countries. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.
Article
Cataract is the leading cause of world blindness. The only available treatment for cataract is surgery. Surgery requires highly-trained individuals with expensive operating facilities. Where these are not available, patients go untreated. A form of treatment that did not involve surgery would be a useful alternative for people with symptomatic cataract who are unable or unwilling to undergo surgery. If an eye drop existed that could reverse or even prevent progression of cataract, then this would be a useful additional treatment option.Cataract tends to result from oxidative stress. The protein, L-carnosine, is known to have an antioxidant effect on the cataractous lens, so biochemically there is sound logic for exploring L-carnosine as an agent to reverse or even prevent progression of cataract. When applied as an eye drop, L-carnosine cannot penetrate the eye. However, when applied to the surface of the eye, N-acetylcarnosine (NAC) penetrates the cornea into the front chamber of the eye (near to where the cataract is), where it is metabolised into L-carnosine. Hence, it is possible that use of NAC eye drops may reverse or even prevent progression of cataract, thereby improving vision and quality of life. To assess the effectiveness of NAC drops to prevent or reverse the progression of cataract. We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2016), Embase (January 1980 to June 2016), Allied and Complementary Medicine Database (AMED) (January 1985 to June 2016), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to June 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 June 2016. We handsearched the American Society of Cataract and Refractive Surgery (ASCRS) and the European Society of Cataract and Refractive Surgeons (ESCRS) meetings from 2005 until September 2015. We planned to include randomized or quasi-randomised controlled trials where NAC was compared to control in people with age-related cataract. We used standard methodological procedures expected by Cochrane. We identified two potentially eligible studies from Russia and the United States. One study was split into two arms: the first arm ran for six months, with two-monthly follow-up; the second arm ran for two years with six-monthly follow-up. The other study ran for four months with a data collection point at the start and end of the study only. A total of 114 people were enrolled in these studies. The ages ranged from 55 to 80 years.We were unable to obtain sufficient information to reliably determine how both these studies were designed and conducted. We have contacted the author of these studies, but have not yet received a reply. Therefore, these studies are assigned as 'awaiting classification' in the review until sufficient information can be obtained from the authors. There is currently no convincing evidence that NAC reverses cataract, nor prevents progression of cataract (defined as a change in cataract appearance either for the better or for the worse). Future studies should be randomized, double-masked, placebo-controlled trials with standardised quality of life outcomes and validated outcome measures in terms of visual acuity, contrast sensitivity and glare, and large enough to detect adverse effects.
Article
The crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina and, by changing shape, it adjusts focal distance (accommodation). The three classes of structural proteins found in the lens are α, β, and γ crystallins. These proteins make up more than 90% of the total dry mass of the eye lens. Other components which can be found are sugars, lipids, water, several antioxidants and low weight molecules. When ageing changes occur in the lens, it causes a gradual reduction in transparency, presbyopia and an increase in the scattering and aberration of light waves as well as a degradation of the optical quality of the eye. The main changes that occur with aging are: 1) reduced diffusion of water from the outside to the inside of the lens and from its cortical to its nuclear zone; 2) crystalline change due to the accumulation of high molecular weight aggregates and insoluble proteins; 3) production of advanced glycation end products (AGEs), lipid accumulation, reduction of reduced glutathione content and destruction of ascorbic acid. Even if effective strategies in preventing cataract onset are not already known, good results have been reached in some cases with oral administration of antioxidant substances such as caffeine, pyruvic acid, epigallocatechin gallate (EGCG), α-lipoic acid and ascorbic acid. Furthermore, methionine sulfoxide reductase A (MSRA) over expression could protect lens cells both in presence and in absence of oxidative stress -induced damage. Nevertheless, promising results have been obtained by reducing ultraviolet-induced oxidative damage. © 2016, International Journal of Ophthalmology (c/o Editorial Office). All rights reserved.
Article
The ciliary muscle plays a major role in controlling both accommodation and outflow facility in primates. The ciliary muscle and the choroid functionally form an elastic network that extends from the trabecular meshwork all the way to the back of the eye and ultimately attaches to the elastic fiber ring that surrounds the optic nerve and to the lamina cribrosa through which the nerve passes. The ciliary muscle governs the accommodative movement of the elastic network. With age ciliary muscle mobility is restricted by progressively inelastic posterior attachments and the posterior restriction makes the contraction progressively isometric; placing increased tension on the optic nerve region. In addition, outflow facility also declines with age and limbal corneoscleral contour bows inward. Age-related loss in muscle movement and altered limbal corneoscleral contour could both compromise the basal function of the trabecular meshwork. Further, recent studies in non-human primates show that the central vitreous moves posteriorly all the way back to the optic nerve region, suggesting a fluid current and a pressure gradient toward the optic nerve. Thus, there may be pressure and tension spikes on the optic nerve region during accommodation and these pressure and tension spikes may increase with age. This constellation of events could be relevant to glaucomatous optic neuropathy. In summary, our hypothesis is that glaucoma and presbyopia may be literally linked to each other, via the choroid, and that damage to the optic nerve may be inflicted by accommodative intraocular pressure and choroidal tension "spikes", which may increase with age.
Article
To evaluate the efficacy of using a parasympathomimetic drug (carbachol) with an alpha agonist (brimonidine) to create optically beneficial miosis to reduce the effect of presbyopia. In this prospective, double-masked, randomized, placebo-controlled clinical trial, 48 naturally emmetropic and presbyopic subjects aged between 43 and 56 years with an uncorrected distance visual acuity of at least 20/20 in both eyes without additional ocular pathology were eligible for inclusion. Subjects were divided into 2 groups. The treatment group (n=30 eyes) received single dose of 2.25% carbachol plus 0.2% brimonidine eye drops. The control group (n=18 eyes) received placebo drops. Drops were given to all subjects in a masked fashion, in their nondominant eye. The minimum posttreatment follow-up was 3 months. The subjects' pupil size and both near and distance visual acuities were evaluated before and after treatment at 1, 2, 4, 8, and 10 hr, by a masked examiner at the same room illumination. Statistically significant improvement in near visual acuity was achieved in all subjects who received carbachol plus brimonidine drops (P<0.0001). In this masked study, all subjects liked and would use this therapy if it was available. None would use the placebo. There was no evidence of tolerance or tachyphylaxis during the study period. Improving the depth of focus by making the pupil smaller caused statistically significant improvement in near visual acuity in emmetropic presbyopic subjects. Carbachol plus brimonidine seem to be an acceptable and safe alternative to corrective lenses and surgical procedures.