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Along with the aging of the population, various comorbidities may arise, such as arthritis, hypertension, and erectile dysfunction. These medical conditions are treated and controlled with various types of medications. In fact, nearly 83% of older adults in Canada take prescription medications by age 65 years. Several of these medications can induce subtle side effects, including decreased visual perception. For instance, previous research indicated that side effects of commonly prescribed type-5 inhibitors (such as Viagra) may include declines in color perception.
Drug-Induced Deficits
in Color Perception:
Implications for Vision
Rehabilitation Professionals
Sarah Zakaib Rassi, Dave Saint-Amour,
and Walter Wittich
Along with the aging of the population, var-
ious comorbidities may arise, such as arthri-
tis, hypertension, and erectile dysfunction
(Glynn, Monane, Gurwitz, Choodnovskiy, &
Avorn, 1999; Ramage-Morin, 2009). These
medical conditions are treated and controlled
with various types of medications. In fact,
nearly 83% of older adults in Canada take
prescription medications by age 65 years. Sev-
eral of these medications can induce subtle side
effects, including decreased visual perception.
For instance, previous research indicated that
side effects of commonly prescribed type-5 in-
hibitors (such as Viagra) may include declines
in color perception (Azzouni & Abu Samra,
2011; Santaella & Fraunfelder, 2007).
Many health care professionals, including
vision rehabilitation therapists (VRTs),
should be aware of the possibility of drug-
induced deficits in color perception when
working with older adults. The main purpose
of this report is, therefore, to identify the com-
monly prescribed medications for age-related
conditions that disturb color vision, and high-
light the colors that are most frequently affected
by these medications. This report aims to pro-
vide professionals who work with older adults
with guidelines on how to identify individuals at
risk for acquired color deficits and how to con-
sider these insufficiencies during various reha-
bilitative interventions.
A scoping review of the literature was con-
ducted to identify the most commonly pre-
scribed medications for age-related condi-
tions like arthritis that can potentially alter
color perception. An advanced search in the
following databases was conducted: PubMed,
EBSCO, and Google Scholar. The main Med-
ical Subject Heading (MeSH) terms that were
used in combination in searching for peer-
reviewed articles included: acquired color
deficits, drug-induced color deficits, side ef-
fects, medications, color vision, drug toxicity,
hydroxychloroquine, type-5 inhibitor, plaque-
nil, ocular adverse effects, and retinal toxic-
ity. Key words found in relevant articles were
added to the search terms. In addition, Bool-
ean terms such as and and or were used to
refine the quest for relevant articles.
Color perception is made possible by three
cone cell types embedded in the retina that are
preferentially sensitive to different wavelengths
of light. The S-cones are sensitive to short
wavelengths (420 nanometers [nm]; also known
as blue-cone). A deficit or absence in S-cones
results in tritanopia, causing a blue-yellow color
deficit or blindness. Similarly, the M-cones are
sensitive to medium wavelengths (535 nm; also
known as green-cone) and the L-cones to long
wavelengths (565 nm; also known as red-
cone). The absence of M- or L-cones results
in deuteranopia or protanopia, respectively. A
deficit in any cone type results in a decreased
ability to detect color hues. Given that the eye
is a high-metabolism organ that contains
many blood vessels, it is susceptible to the
effects of systemic medications (Santaella &
Fraunfelder, 2007). It was long thought that
congenital color deficits were more common
than acquired ones. In fact, approximately 8%
of males and 0.5% of females are diagnosed
with a congenital color deficit (Simunovic,
2010). However, some researchers argue that
acquired color deficits are more prevalent
than previously thought; a study conducted in
North America revealed that the prevalence
rate is 20.8% for older adults between ages 58
and 102 years (M75.2) (Simunovic, 2016).
The research was supported in part by the vision
health research network (FRQS), CHU Sainte-
Justine Research Center, and the CRIR/Centre de
re´adaptation MAB-Mackay du CIUSSS du Centre-
448 Journal of Visual Impairment & Blindness, November-December 2016 ©2016 AFB, All Rights Reserved
The effects of acquired color deficits can vary
widely. For instance, some may develop
problems in the red-green color axis (deuter-
anopia/protanopia), and others in the yellow-
blue axis (tritanopia). Nevertheless, the most
common type of acquired color deficit is in
the blue-yellow axis. An Iranian study re-
vealed that 66.1% of acquired color deficits
result in tritanopia (Jafarzadehpur et al.,
2014). There are several causes for declines in
color perception, but the most common ones
are natural decline with age or as a result of
medication intake (Delpero, O’Neill, Casson,
& Hovis, 2005).
Six drug types frequently prescribed to se-
niors that can potentially alter color perception
were identified. Lanoxin, known under the ge-
neric name Digoxin, is commonly used to
treat various heart conditions. This drug is a
cardiac stimulant, increasing the strength and
efficiency of the heart muscle (Lawrenson,
Kelly, Lawrenson, & Birch, 2002). It is often
used to treat conditions such as arrhythmia
(arterial fibrillation). The risk of developing
arrhythmia increases with age and is strongly
associated with other age-related conditions
such as hypertension and diabetes (Du et al.,
2009). Moreover, Lanoxin consumption has
been associated with xanthopsia, a condition
that results in yellow-tinted vision due to yel-
lowing of the optic media or lens of the eye
(Carlson & Buck, 2002). It has also been
associated with tritanopia, making color pairs
such as green-blue, as well as yellow-violet,
difficult to discriminate (Lawrenson et al.,
2002). Similarly, Lasix (Furosemide) is a di-
uretic often prescribed in combination with
hypertension medication and can cause
yellow-tinted vision (Carlson & Buck, 2002).
Hydroxychloroquine, commonly known as
Plaquenil, is another drug that can result in
color vision alterations. Plaquenil is an anti-
malarial drug that is at times prescribed for
rheumatoid arthritis (Santaella & Fraunfelder,
2007). It has been estimated that 50.6% of
women and 33.8% of men ages 65 or older
have an arthritis diagnosis. These percentages
increase to 53% for women and 40% for men
by 75 years of age (Statistics Canada, 2015).
Therefore, it is likely that many seniors take
arthritis medication to reduce inflammation
and pain. Santaella and Fraunfelder (2007)
reported that Plaquenil can result in deficits in
the yellow-blue axis of the color spectrum,
making blue and green, as well as yellow and
violet, difficult to discriminate.
Sildenafil, commercially known as Viagra,
is another drug that can alter color vision and
is frequently prescribed to older men. In fact,
it has been estimated that 42% of men aged 60
to 69 years have moderate to severe erectile
dysfunction. Among men aged 70 years or
older, the proportion rises to approximately
70% (Grover et al., 2006). The frequency and
severity of erectile dysfunction increases with
age and is a worldwide occurrence (Nicolosi,
Moreira, Shirai, Tambi, & Glasser, 2003).
Therefore, many older men take type-5 inhib-
itors (such as Viagra), which increase blood
flow to smooth muscles, resulting in a higher
probability of getting and maintaining an
erection during intercourse (Stockman et al.,
2007). Viagra can result in trouble discrimi-
nating colors such as blue, purple, and green,
often described by men as “bluish vision.”
The literature on Viagra is, however, contro-
versial; although some studies show no sig-
nificant changes in color vision compared to
the general population (Azzouni & Abu
Samra, 2011), others report color vision al-
terations (Santaella & Fraunfelder, 2007). But
all studies agree that effects of Sildenafil on
color vision are transient and reversible (Lat-
ies & Zrenner, 2002; Li, Tripathi, & Tripathi,
Tamoxifen (Nolvadex) is a drug used to
reduce the risk of breast cancer. One
of the main risk factors for developing breast
cancer is age (Yancik, Ries, & Yates, 1989),
making this medication more likely pre-
scribed to older women. Approximately 13%
of Tamoxifen users report visual changes
©2016 AFB, All Rights Reserved Journal of Visual Impairment & Blindness, November-December 2016 449
related to the drug. Similarly to Hydroxychlo-
roquine and Sildenafil, it can also result in
blue-yellow axis deficits. In addition, it can
result in corneal opacity and cataracts, leading
to yellowing vision (Li et al., 2008).
Mechanisms underlying the changes in
color vision resulting from medication intake
are debated in the literature. Various theories
explaining the reasons for which the S-cones
are more affected than L- and M-cones in
acquired color deficits are well defined in a
recent article by Simunovic (2016). It is im-
portant to note that drug-induced color defi-
cits resulting from medications are merely a
possible side effect. Only a small proportion
of older adults taking these drugs experience
a decline in color vision. In addition, the unde-
sired side effects are often reversible with drug
discontinuation. Drug toxicity is also said to be
dose and time dependent; higher doses and lon-
ger periods of drug intake increase the risk of
developing drug toxicity (Santaella & Fraun-
felder, 2007).
Color-coding interventions
in visual rehabilitation
Cooper, Gowland, and McIntosh (1986) indi-
cated that color coding and color highlighting
are types of intervention often used in reha-
bilitation for age-related vision loss (for ex-
ample, age-related macular degeneration).
One example of rehabilitative color-coding
for seniors with low vision is fixing a colored
sticker on the start button of a microwave to
facilitate its localization and identification. If
older adults receiving this type of intervention
have a drug-induced color deficit, such a
color-specific rehabilitation technique may
not be optimal, and a focus on high contrast
may be more advisable. Thus, it is crucial for
VRTs to be aware of colors that are most
commonly affected by prescription drugs, al-
lowing more efficient color-coding interven-
tions for clients. Given that most drug-
induced color deficits affect S-cones or result
in yellowish vision, colors such as blue, green,
yellow, purple, and violet should be avoided.
Some VRTs use primarily high-contrast colors
and tactile stickers in their interventions, allow-
ing vision-impaired patients to use their sense of
touch to identify the location of important but-
tons. Such a type of home intervention is likely
unaffected by drug-induced color deficiencies
such as tritanopia and xanthopsia, and thus
might be the most efficient method for VRTs
working with seniors.
Medication discrimination. Many older
adults rely on the color of pills to identify
and discriminate them, and to know which
ones to take and when. Thus, pharmaceutical
industries should consider the importance
of colors that may be confused and those that
are less easily distinguished, in order to de-
crease the probability of drug-intake errors. It
is important to note that many seniors are not
aware of their color perception deficits, since
they develop gradually and are not apparent
to friends and family (Rigby, Warren, Dia-
mond, Carter, & Bradfield, 1991). Even se-
niors who are not affected by drug-induced
color deficits may have difficulties identifying
low-contrast, pastel-colored pills, since older
adults experience a natural decline in color
perception with age (Cooper, Ward, Gow-
land, & McIntosh, 1991). Therefore, it is
in the best interest of pill manufacturers
to make medications easily distinguishable.
One option is to place greater emphasis
on the shape rather than the color of pills.
VRTs should assist their patients in address-
ing this potential problem by ensuring that
similarly colored pills are distinguished in an-
other way. For instance, the bottle of pills can
be marked with tactile stickers (such as one
tactile sticker for morning pills and two
for nighttime pills).
Assistive technology. The presence of drug-
induced color deficits should also be consid-
ered by companies designing assistive tech-
nology devices. Seniors often use these
450 Journal of Visual Impairment & Blindness, November-December 2016 ©2016 AFB, All Rights Reserved
devices to facilitate activities of daily living
like reading. Thus, it is important to consider
that the use of blue, yellow, green, and violet
on the buttons and controls of these devices
may induce color discrimination issues
for those with acquired color deficit. VRTs
should ensure that their patients are capable
of identifying all buttons on their assistive
technology devices, especially when they are
meant to be distinguished by color. If this is
not the case, tactile stickers can again be used
as a code (for instance, one for start and two
for stop). There are many other professionals
who can benefit from information on colors
affected naturally with age or with certain med-
ications. Not only is this information relevant
in the domain of health care, but also for many
marketing efforts that target seniors. For in-
stance, to highlight nutritious cereals containing
low sodium, low sugar, and high calcium,
the box design should be displayed in high-
contrast colors that most seniors can perceive.
Most color vision tests were designed to de-
tect red-green color blindness, since it was
long thought to be the most common type
(Wong, 2011). However, recent studies show
that acquired color deficits are more prevalent
than believed (Delpero et al., 2005). The most
frequently used color tests (such as Ishihara
and Farnsworth D-15) have been designed to
detect congenital defects and lack the sensi-
tivity to reveal acquired color deficits. There
are nonetheless multiple tests created to address
this issue. The utility and generalizability of
color tests, therefore, should be well understood
before testing color vision in seniors taking var-
ious systemic medications (some tests are more
appropriate to detect acquired color deficits,
most often in blue-yellow axis).
City University Test
The City University Test (CUT) is very sim-
ilar to Farnsworth D-15, but is useful in de-
tecting yellow-blue color deficits (tritanopia).
The Farnsworth D-15 test requires good dex-
terity, since patients are asked to sort small
pastels in chromatic order. Instead, the CUT
is a 10-page book containing five colored
circles on each page, one central reference
color, and four testing colors (Hasrod & Ru-
bin, 2015). The patient is required to identify
the test color that matches the center
reference color. Three other colors lie on the
dichromatic confusion lines, one of which is
meant to confuse patients with tritanopia.
This test has the advantage of not requiring
fine dexterity, which is useful when working
with older adults.
Cambridge Color Test
The Cambridge Color Test (CCT) is a
computer-based test that shares similarities
with the Ishihara test. However, the colored
plates include identifying blue-yellow axis
confusion colors. It is important for the colors
of tests to remain constant over time; how-
ever, colors that are printed rather than those
that are generated by computers can vary
slightly over time and affect results. There-
fore, the computer-based CCT has the advan-
tage of its colors remaining constant over
time. In addition, the difficulty level can be
adjusted for each individual patient, making
the test suitable for a large array of deficits.
During this test, the patient is presented with
the letter Cin a specific luminance and hue,
embedded in various backgrounds of colored
circles. Patients must identify the orientation of
the letter by using a four-alternative forced-
choice paradigm: up, down, right, or left (Has-
rod & Rubin, 2015). Similar to the CUT, this
test does not require manual dexterity.
Color Assessment and Diagnosis
The Color Assessment and Diagnosis (CAD)
test is efficient in detecting all three kinds of
color vision deficits. Because it is computer
based, changes in luminance and contrast
over time are controlled. It requires the
©2016 AFB, All Rights Reserved Journal of Visual Impairment & Blindness, November-December 2016 451
patient to identify the direction of the moving
colored dot on a computer screen, and thus
does not necessitate dexterity (Rodriguez-
Carmona, Harlow, Walker, & Barbur, 2005),
making it suitable to examine drug-induced
color deficits in older adults.
Mollon Reffin Test
The Mollon Reffin test is useful in detecting
most types of color vision discrimination def-
icits, including tritan confusions. Interest-
ingly, this test has also been created in a
larger format to facilitate detection of ac-
quired color deficits in patients with low vi-
sion (Simunovic, 2010).
The list presented here is not an exhaustive
inventory of all color tests that can be used to
assess acquired loss of chromatic sensitivity,
and a more extensive review is available else-
where (Simunovic, 2016). In addition, these
tests can be used alone or in combination. It is
up to the clinician to determine the best
course of action based on the capacities of
each individual.
Most cone photoreceptors responsible for en-
coding color are found in the macula (the
centre of the retina). This region of the eye
can degenerate with age, progressively affect-
ing color vision for older adults (Simunovic,
2016). The majority of seniors take multiple
types of medications per day for various age-
related conditions. In addition to a natural
decline in color vision, studies show that a
variety of medications can result in color vi-
sion deficits as well. It is not uncommon for
seniors to be unaware of such color deficits.
Thus, it is important for health care profession-
als to consider the possibility of drug-induced
color deficits, and to have the tools to screen for
drug toxicity. The color deficits reported from
the intake of systemic medications are often in
the blue-yellow axis of the color spectrum,
which can result in confusion between blue,
purple, and green, as well as for between yellow
and violet. This information is important for
health care professionals working with seniors,
as well as for those who market products to this
population. To increase the visibility and prac-
ticability of their interventions (such as tactile
stickers) or products (such as pills), profession-
als should avoid such colors. The problem of
drug-induced color deficits is one that is more
prevalent than expected and deserves attention
from health care professionals such as VRTs.
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Sarah Zakaib Rassi, B.A., doctoral researcher,
Department of Psychology, Universite´ du Que´bec
a` Montre´al, C.P. 8888 Succ. Centre-Ville, Mon-
tre´al, H3C 3P8, Canada; e-mail: zakaib_rassi. Saint-Amour,
Ph.D., associate professor, Department of Psy-
chology, Universite´ du Que´bec a` Montre´ al,
Centre-Ville, Montre´al, Canada; e-mail: saint- Wittich, Ph.D.,
FAAO, CLVT, assistant professor, CRIR/Centre
de re´adaptation MAB-Mackay du CIUSSS du Cen-
ˆle-de-Montre´al; School of Optom-
etry, University of Montreal, 3744, rue Jean-
Brillant, room 260-7, Montre´al, Que´bec, H3T 1P1,
Canada; e-mail:
©2016 AFB, All Rights Reserved Journal of Visual Impairment & Blindness, November-December 2016 453
... Xanthopsia (yellow colored vision), cyanopsia (blue colored vision), and erythropsia (red colored vision) are well described chromatopsias that result in altered color perception and have been observed in various disorders. [2][3][4][5][6][7][8] These chromatopsias often occur due to damage to photoreceptors or retinal ganglion cells. 2 However, central chloropsia, which causes green tinged vision is rare. We describe a unique case of cerebral chloropsia as the presenting symptom of CBS secondary to primary open-angle glaucoma. ...
... Systemic, non-hallucinogenic medications can cause chromatopsia. 4,7,8 Digoxin may cause yellowing of the optic media and has been associated with xanthopsia. 7 Phosphodiesterase type 5 inhibitors can inhibit cone-specific phosphodiesterase and induce cyanopsia. ...
Full-text available
Purpose Chloropsia (green-colored vision) is an extremely uncommon and relatively unstudied clinical finding. We report a case where cerebral chloropsia was the presenting symptom of the Charles Bonnet syndrome. Observations A 66-year-old male physician with a previous ocular history of advanced bilateral primary open-angle glaucoma presented with acute, diffuse chloropsia, which he described as “light green and oval-shaped.” The patient was not taking any drugs that commonly cause altered color perception and did not have a previously diagnosed psychiatric disorder. Ophthalmic examination findings showed poor visual acuity, central visual field loss, and altered color perception in both eyes. Common laboratory tests and visual imaging showed no abnormalities that could be associated with the patient's symptoms. Conclusions and Importance Our patient meets all diagnostic criteria for Charles Bonnet syndrome, even though, to the best of our knowledge, chloropsia has never been previously associated with this disorder. Physicians should monitor patients for altered color perception, which cannot be explained by other ocular, psychiatric, or systemic mechanisms, as this could be a sign of Charles Bonnet syndrome.
... It can also be acquired through such chronic illnesses that damage the retina, optic nerve, and the brain as diabetes mellitus, sickle cell anemia, and retinitis pigmentosa, or the use of some medications such as sildenafil, digoxin, ethambutol, furosemide, metronidazole, and some antimalarials. [1,2] CVD occurs when light-sensitive cells in the retina fail to respond appropriately to variations in wavelengths of light that enable people to see an array of colors. [3] Several tools used to assess CVD in clinical practice are suitable for primary care physicians. ...
Full-text available
Background: Color vision deficiency (CVD) affects approximately one in 12 men and one in 200 women in the world. It is considered a problem in the medical field since the color is often used as a sign in the practice of medicine, in observational assessment, diagnosis, and follow-up. These conditions make the appreciation of color essential in doctors' lives, thus we aimed at finding the prevalence and predictors of CVD in medical students. Materials and methods: This cross-sectional study included 1115 medical students. A pretested questionnaire consisting of personal data, history of vision problems, familial color vision defect, eye surgery, bad trauma on the head or eyes, drugs taken or chemicals exposed to, other health problems, and whether sufficient amount of Vitamin A is taken was used. This was followed by the screening of the participants for CVD using the Ishihara 15-plates test. Results: A total of 1115 students participated in the study; 52.2% were females and the mean age of the participants was 21.7 years (±1.4). The prevalence of definitive CVD was found to be 2.1%; all of which comprised males. Eighty-seven percent of the affected participants were not aware of their color vision problem. A highly statistically significant association was found between history of vision problems and CVD status (P < 0.008). No association were found for nationality, marital status, family history of CVD, history of eye surgery, and eye trauma. Conclusion: The percentage of CVD in the present study is lower than that reported by previous studies done in other countries. Many medical students with CVD remain unaware of their condition. Therefore, we recommend early screening of all school-age children, and proper counseling of medical students with definite CVD to take care of their own health and wellbeing.
... Currently, none of the available displays is able to provide the exhaustive range of colors that people without visual impairment can perceive under photopic conditions. Adverse effects on color perception remain all the more important to consider as individuals with visual impairment can have additional reductions in color vision (Rassi et al., 2016). ...
... 3 However, colour blindness can also be secondary to ocular and intracranial pathologies, diseases like diabetic retinopathy, hypertension, glaucoma, macular degeneration, and yellowing of the lens owing to ageing 3 and drugs. 4 The early detection of CVD is necessary for the person to choose the career option commensurate with his colour vision or lack of it. Some occupations like in transport, electrical industries, armed forces, as well as technical jobs like software programming require normal colour vision, though the criteria of requirement of normal colour vision for obtaining license for driving has been recently relaxed by the Government of India. ...
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Introduction: Colour vision defect (CVD) is the inability to perceive colour differences under normal lighting conditions. Its prevalence, thought to be around 8% for men and 0.4% for women, vary from country to country, between regions in the same country, as well as between ethnic groups. Its importance lies in the fact that it prevents a person from carrying out certain jobs while creating difficulties in others. Screening for CVD during childhood and counselling to guide them towards choosing appropriate career needs to be carried out.
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The evaluation of colour vision and discrimination of an individual forms an integral part of a routine eye and vision examination. With the increasing prevalence of inherited colour vision deficiencies, defects of colour vision can be detected in an optometric practice by means of a variety of tests available. The present article comprises an overview of the design and function of a selection of colour vision tests that are administered manually and, in some cases, have been modified to form a computerised version.
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Colour vision deficiency is one of the commonest disorders of vision and can be divided into congenital and acquired forms. Congenital colour vision deficiency affects as many as 8% of males and 0.5% of females--the difference in prevalence reflects the fact that the commonest forms of congenital colour vision deficiency are inherited in an X-linked recessive manner. Until relatively recently, our understanding of the pathophysiological basis of colour vision deficiency largely rested on behavioural data; however, modern molecular genetic techniques have helped to elucidate its mechanisms. The current management of congenital colour vision deficiency lies chiefly in appropriate counselling (including career counselling). Although visual aids may be of benefit to those with colour vision deficiency when performing certain tasks, the evidence suggests that they do not enable wearers to obtain normal colour discrimination. In the future, gene therapy remains a possibility, with animal models demonstrating amelioration following treatment.
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Based on data from the 1996/1997 (institutional component) and 1998/1999 (household component) National Population Health Survey, seniors were major consumers of prescription medications, over-the-counter (OTC) products, and natural and alternative medicines. Almost all (97%) seniors living in long-term health care institutions were current medication users (medication use in the two days before their interview), as were 76% of those living in private households. Over half (53%) of seniors in institutions and 13% of those in private households used multiple medications (currently taking five or more different medications). Both medication and multiple medication use were associated with morbidity. Medications for the nervous system, the alimentary tract and metabolism, and the cardiovascular system were reported most frequently. Among seniors in institutions, those with Alzheimer's disease were less likely to take multiple medication than were those without this condition.
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The aim of this study was to investigate serious clinical outcomes associated with atrial fibrillation (AF) and the effects of routine blood pressure lowering on such outcomes in the presence or absence of AF, among individuals with type 2 diabetes. About 11 140 patients with type 2 diabetes (7.6% of whom had AF at baseline) were randomized to a fixed combination of perindopril and indapamide or placebo in the Action in Diabetes and Vascular Disease: preterAx and diamicroN-MR Controlled Evaluation (ADVANCE) study. We compared total mortality and cardiovascular disease outcomes and effects of randomized treatment for 4.3 years on such outcomes between patients with and without AF at baseline. After multiple adjustments, AF was associated with a 61% (95% confidence interval 31-96, P < 0.0001) greater risk of all-cause mortality and comparable higher risks of cardiovascular death, stroke, and heart failure (all P < 0.001). Routine treatment with a fixed combination of perindopril and indapamide produced similar relative, but greater absolute, risk reductions for all-cause and cardiovascular mortalities in patients with AF, compared with those without AF. The number of patients needed to be treated with perindopril-indapamide for 5 years to prevent one cardiovascular death was 42 for patients with AF and 120 for patients without AF at baseline. Atrial fibrillation is relatively common in type 2 diabetes and is associated with substantially increased risks of death and cardiovascular events in patients with type 2 diabetes. This arrhythmia identifies individuals who are likely to obtain greater absolute benefits from blood pressure-lowering treatment. Atrial fibrillation in diabetic patients should be regarded as a marker of particularly adverse outcome and prompt aggressive management of all risk factors.
Acquired color vision deficiency occurs as the result of ocular, neurological or systemic disease. A wide array of conditions may affect color vision, ranging from diseases of the ocular media through to pathology of the visual cortex. Traditionally, acquired color vision deficiency is considered a separate entity from congenital color vision deficiency, though emerging clinical and molecular genetic data would suggest a degree of overlap. We review the pathophysiology of acquired color vision deficiency, the data on its prevalence, theories for the preponderance of acquired S-mechanism (or tritan) deficiency, and discuss tests of color vision. We also briefly review the types of color vision deficiencies encountered in ocular disease, with an emphasis placed on larger and/or more detailed clinical investigations.
The aim of this study was to determine the prevalence of color vision defects in the middle-age population of Shahroud, Iran. We selected 6,311 people from the 40- to 64-year-old population through random cluster sampling. Color vision testing was performed with the Farnsworth D-15. Cases with similar and symmetric results in both eyes were classified as hereditary, and those with asymmetric results were considered acquired. Cases that did not conform to standard patterns were classified as unknown category. Of 5,190 respondents (response rate 82.2 %), 5,102 participants underwent the color vision test. Of these, 14.7 % (95 % confidence interval 13.7-15.6) had some type of color vision deficiency. Of the 2,157 male participants, 6.2 % were hereditary and 10.2 % were acquired and of the 2,945 female participants, 3.1 % were hereditary and 10 % were acquired. Hereditary color deficiencies were mostly of the deutan form (63.8 %), and acquired deficiencies were mostly tritan (66.1 %). The prevalence of hereditary and acquired color vision deficiency, as well as different types of red-green and blue-yellow color vision defects significantly increased with age (p < 0.001). In conclusion, the pattern of color vision defects among the middle-aged population of Shahroud was significantly different from that seen in the younger population. This could be due to changes associated with age, gender, medical and ocular conditions, and differences in race and environment. Thus, results of previous examinations and the overall health status should be considered before making any judgment about the status of color vision in middle-aged people.
A new Colour Assessment and Diagnosis (CAD) test has been developed and optimised to measure small changes in chromatic sensitivity. In addition the test quantifies the severity of red- green and yellow-blue loss and classifies accurately even minimal congenital deficiencies. The technique employed makes use of dynamic luminance contrast (LC) noise to mask the detection of any residual LC signals in the test stimulus. The LC noise provides effective masking of LC signals without affecting the thresholds for detection of colour signals (Proc.R.Soc.Lond. B Biol.Sci. 258: 327-334, 1994). Chromatic discrimination thresholds are plotted in the CIE-(x,y) 1931 colour system. 125 normal trichromats have been tested in order to validate the CAD test and to derive a template that describes the range of normal colour discrimination sensitivity.
Introduction: Phosphodiesterase type 5 (PDE5) inhibitors are the first line drugs for treatment of erectile dysfunction. Sildenafil (Viagra(R)), tadalafil (Cialis(R)), and vardenafil (Levitra(R)) are from the same class of drugs that inhibit PDE5. Transient visual symptoms such as change in color perception and increased light sensitivity are well-known adverse effects of these drugs and occur in 3-11% of sildenafil users. Vision-threatening (serious) ocular complications, such as nonarteritic ischemic optic neuropathy and cilio-retinal artery occlusion have rarely been reported in PDE5 inhibitor users. Aims: To highlight and analyze the most recently published case literature on serious ocular complications of PDE5 inhibitors. Methods: Search of the peer-reviewed English literature was conducted using Medline. The following databases also were searched: Cumulative Index to Nursing and Allied Health Literature, Cochrane Library, Global Health, and MD Consult. The causality assessment of the reported adverse drug reactions was analyzed by applying both the World Health Organization (WHO) Probability Scale and the criteria utilized by the National Registry of Drug-Induced Ocular Side Effects. Main outcome measures: To scientifically and objectively find out if PDE5 inhibitors are associated with vision-threatening ocular complications. Results: Eight case reports of serious PDE5 inhibitor-associated ocular complications were identified since January 2006 until February 2011. Case reports included cases of anterior and posterior nonarteritic ischemic optic neuropathy, central retinal vein occlusion, cilio-retinal artery occlusion, acute angle closure glaucoma and optic atrophy after sildenafil use. Conclusion: There is lack of conclusive evidence to indicate a direct cause-effect relationship between PDE5 inhibitor use and vision-threatening ocular events. Men who use PDE5 inhibitors appear to suffer vision-threatening complications at the same frequency as the general population. However, minor visual adverse effects occur in 3-11% of users and they are transient and reversible.