Article

Reducing Light Intensity and Changing its Spectral Composition: Effects on Human!s Sleep Characteristics and Melatonin Suppression Under "Natural Conditions

Authors:

Chrono@Work BV

Light has a great impact in our everyday life for vision, but also for non-visual processes. The recent discovery of photosensitive retinal ganglion cells triggers new studies on the non-visual effects of light's spectral composition. In the present study via the use of soft orange contact lenses we investigated how, under natural conditions, a reduction in exposure to the short wavelengths (blue) light affects sleep and the suppression of melatonin concentrations to a standard light stimulus in healthy young subjects. The orange lenses were effective in reducing light input. If worn only during the light pulse melatonin suppression in response to a 2h 600 lux white light pulse was reduced from 29% in the control condition to 17.3% (p

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Article

Influence of Contact Lens Power Profile on Peripheral Refractive Error

May 2014 · Optometry and vision science: official publication of the American Academy of Optometry

To measure the power profile across the optic zone (OZ) of four commercially available soft contact lenses and establish the impact on the peripheral refractive error of the eye. The power profiles of a spherical conventional hydrogel contact lens (etafilcon A, J&J Vistakon, Jacksonville, FL USA) and three spherical silicone hydrogel contact lenses (lotrafilcon A and B, CIBA Vision, Duluth, GA ... [Show full abstract] USA; enfilcon A, CooperVision, Pleasanton, CA USA) with a labeled power of -3.00 and -6.00 diopters were measured using a Shack-Hartmann wavefront sensor power mapping device. Central and peripheral refraction across the horizontal meridian (nasal and temporal visual field at 20, 30, and 40 degrees) was measured with an open-field autorefractor (Shin Nippon NVision K5001, Osaka Japan) with and without contact lenses in 26 myopic subjects. The relative peripheral refractive error on the eye was estimated and compared with and without contact lenses and between contact lenses. Differences in the distribution of the power profile across the OZ were apparent between contact lens types and powers. No significant differences (p > 0.05) were found between contact lens types for their effect on on-axis refraction. Significant differences (p < 0.05) were found at all peripheral retinal eccentricities between contact lens types. For a given central power, the four contact lenses exhibited variations in optical power across the OZ of the lens. The distribution of optical power across the OZ has an influence on the peripheral refractive error of the eye.

Article

Soft wearable contact lens sensor for continuous intraocular pressure monitoring

September 2014 · Medical Engineering & Physics

Intraocular pressure (IOP) is a primary indicator of glaucoma, but measurements from a single visit to the clinic miss the peak IOP that may occur at night during sleep. A soft chipless contact lens sensor that allows the IOP to be monitored throughout the day and at night is developed in this study. A resonance circuit composed of a thin film capacitor coupled with a sensing coil that can sense ... [Show full abstract] corneal curvature deformation is designed, fabricated and embedded into a soft contact lens. The resonance frequency of the sensor is designed to vary with the lens curvature as it changes with the IOP. The frequency responses and the ability of the sensor to track IOP cycles were tested using a silicone rubber model eye. The results showed that the sensor has excellent linearity with a frequency response of ∼8 kHz/mmHg, and the sensor can accurately track fluctuating IOP. These results showed that the chipless contact lens sensor can potentially be used to monitor IOP to improve diagnosis accuracy and treatment of glaucoma.

Article

Rigid Gas-Permeable Contact Lenses for Visual Rehabilitation of Traumatized Eyes in Children

March 2014 · Cornea

The aim of this study was to investigate the usefulness and tolerance of rigid gas-permeable (RGP) contact lenses in the visual rehabilitation of children postocular trauma. In this retrospective case series, children below 15 years of age with ocular trauma were included. The best-corrected visual acuity with RGP contact lenses was compared with that of spectacle correction. The factors ... [Show full abstract] affecting visual improvement were analyzed, and problems caused by contact lens use were identified. Twelve eyes of 12 boys were included. The mean best-corrected visual acuity was 0.81 ± 0.29 (LogMar equivalent) with spectacles and 0.47 ± 0.27 (LogMar equivalent) with contact lenses (P < 0.001). Seven of the 12 eyes achieved a >2 line increase in visual acuity with contact lens correction as compared with that using spectacle correction. The mean astigmatism in eyes that achieved this improvement in vision was 5.45 ± 1.6 diopters, whereas the mean astigmatism in the eyes that did not improve was 2.6 ± 1.2 diopters, which was statistically significant (P = 0.009). No other factors (age, corneal scar location/density, grade/zone of injury, lens status, and occlusion) seemed to affect visual improvement with contact lenses. The mean follow-up duration was about 15 months during which 91% of the patients continued their contact lens usage. RGP contact lenses offer a useful refractive treatment alternative in traumatized eyes of children. Eyes with high degrees of astigmatism were found to benefit the most. RGP contact lenses were found to be well tolerated in this population.

Article

Full-text available

A multicenter investigation of OPTI-FREE(RM) RepleniSH(RM) multi-purpose disinfecting solution impac...

January 2010 · Clinical Ophthalmology

Glenn S Corbin1, Linda Bennett2, Louis Espejo3, Suzanne Carducci4, Andrew Sacco5, Robert Hannigan6, Stuart Schatz71Wyomissing Optometric Center, Wyomissing, PA, USA; 2Bellmont, MA, USA; 3Rockville, MD, USA; 4Gaithersburg, MD, USA; 5Vestal, NY, USA; 6Taunton, MA, USA; 7College Park, MD, USAObjective: Demonstrate that successful soft contact lens wearers using competitive multipurpose solutions ... [Show full abstract] report improvement in comfort with OPTI-FREE® RepleniSH® Multi-Purpose Disinfecting Solution (MPDS).Methods: This 30-day, multicentered, open-label study enrolled 109 eligible soft contact lens wearers using COMPLETE® Multi-Purpose Solution (MPS) Easy Rub® or ReNu MultiPlus® MPS. The test solution (OPTI-FREE® RepleniSH® MPDS) was dispensed for use in place of habitual care solutions. Subjects assessed their experience with their habitual solution (baseline) and the test solution (Day 30) using Likert-style questions. Contact lens acuity and biomicroscopy findings were recorded at each visit.Results: The test solution was associated with a statistically significant improvement in instillation comfort (P = 0.02), end of day comfort (P < 0.0001), clear vision (P < 0.0001) and overall satisfaction (P < 0.001). Subjects reported the test solution enhanced their overall lens-wearing experience more effectively than their previous solution (P < 0.0001) and that they would continue test solution use after the study (P < 0.0001).Conclusions: The test solution was effective at improving comfort and overall contact lens experience compared to COMPLETE® MPS Easy Rub® or ReNu MultiPlus® MPS in successful contact lens wearers. These results indicate that changing contact lens care solutions, even in successful lens wearers, may improve comfort and overall lens-wearing experience.Keywords: multipurpose solution, soft contact lens, disinfecting solution, patient comfort

Article

Aberraciones ópticas en ojos con lentes de contacto medidas con el sistema de trazado de Rayos

October 2006 · Archivos de la Sociedad Española de Oftalmología

Purpose:To evaluate the impact of disposable soft contact lenses upon visual performance by comparing the optical aberrations of myopic eyes with and without the use of contact lenses. Method: The optical aberrations of a set of 18 eyes were measured by a laser ray tracing system, an objective measurement method, enabling comparison of the findings of the naked eye, the eye plus a test lens, and ... [Show full abstract] the eye plus a disposable contact lens. Results: There was a large variability among subjects, but the general tendency was that test lenses did not modify aberrations, whereas contact lenses tended to increase the ocular aberrations for large pupils by an average of 40%. There was a lower increase for smaller pupils. Conclusion: This study predicts there will be no significant adverse effects on the quality of vision from the use of disposable contact lenses worn under daylight conditions, but a small decline in night vision (Arch Soc Esp Oftalmol 2006; 81: 575-580).

Article

Full-text available

Clinical performance of KeraSoft IC in irregular corneas

October 2015 · Clinical Ophthalmology

Purpose This study evaluated the clinical performance of KeraSoft® IC (KIC) soft contact lenses in subjects with irregular corneas. Patients and methods This was a 12-month, prospective, open-label, observational study, which enrolled 43 subjects who were 18 years of age or older with irregular corneas. Subjects were fit according to the KIC Fitting Manual (kerasoftic.com). After achieving best ... [Show full abstract] fit according to the fitting manual, lenses were assessed for comfort, vision, centration, rotation, and movement. Subjects were instructed to wear their lenses between 8 and 16 hours each day. Assessments at the exit visit included logMAR visual acuity with high and low contrast, spherocylindrical overrefraction, slit-lamp findings, adverse events, and subjective outcomes. Results The average base curve was 8.17±0.32 mm (n=70 eyes), and the average diameter dispensed was 14.53±0.12 mm (n=70 eyes). From the baseline to 12 months, there was statistically significant improvement in logMAR visual acuity with high contrast (P=0.038), but no significant difference in low-contrast visual acuity was observed (P>0.05). Slit-lamp findings were ≤ grade 1 for the majority of subjects (89%). Two nonserious adverse events were reported for two of the 84 enrolled eyes (two subjects). At 12 months, subjects reported improvements from habitual baseline for comfort and vision, both upon insertion and just before removal of lenses. Conclusion Clinical outcomes at 12 months showed good visual, safety, and subjective outcomes for subjects with corneal irregularities who wore KeraSoft® IC soft contact lenses.

Article

International Survey of Rigid Contact Lens Fitting

December 2012 · Optometry and vision science: official publication of the American Academy of Optometry

Purpose: To determine the extent of rigid contact lens fitting worldwide and to characterize the associated demographics and fitting patterns. Methods: Survey forms were sent to contact lens fitters in up to 40 countries between January and March every year for five consecutive years (2007 to 2011). Practitioners were asked to record data relating to the first 10 contact lens fits or refits ... [Show full abstract] performed after receiving the survey form. Survey data collected between 1996 and 2011 were also analyzed to assess rigid lens fitting trends in seven nations during this period. Results: Data were obtained for 12,230 rigid and 100,670 soft lens fits between 2007 and 2011. Overall, rigid lenses represented 10.8% of all contact lens fits, ranging from 0.2% in Lithuania to 37% in Malaysia. Compared with soft lens fits, rigid lens fits can be characterized as follows: older age (rigid, 37.3 ± 15.0 years; soft, 29.8 ± 12.4 years); fewer spherical and toric fits; more bifocal/multifocal fits; less frequent replacement (rigid, 7%; soft, 85%); and less part-time wear (rigid, 4%; soft, 10%). High-Dk (contact lens oxygen permeability) (36%) and mid-Dk (42%) materials are predominantly used for rigid lens fitting. Orthokeratology represents 11.5% of rigid contact lens fits. There has been a steady decline in rigid lens fitting between 1996 and 2011. Conclusions: Rigid contact lens prescribing is in decline but still represents approximately 10% of all contact lenses fitted worldwide. It is likely that rigid lenses will remain as a viable, albeit increasingly specialized, form of vision correction.

Article

Monovision vs. soft diffractive bifocal contact lenses: A crossover study

July 1990 · International Contact Lens Clinic

The relative clinical performance of monovision and the Hydro® ECHELON® soft diffractive bifocal contact lens were evaluated in a 1 -month, two-period, open-label crossover study. Wearers' subjective impressions were also elicited. Monovision provided superior low contrast acuity and the bifocal better stereopsis. No difference was found for high-contrast visual acuity or physiological signs. ... [Show full abstract] Although monovision was subjectively preferred for reading, no difference was found for other subjective variables. These included visual quality ratings at far and intermediate viewing distances, under dimly lit conditions, when driving at night, and for overall preference. Similiar patient acceptance can be expected for both modalities. The results of this study reflect a significant improvement in performance of the diffractive bifocal lens over previous simultaneous vision bifocal contact lens damage.

Article

Profile of contact lens failures in Saudi Arabia

November 1996 · Clinical and Experimental Optometry

Stella T Briggs

Background: Interest in contact lenses is increasing in Saudi Arabia, as in many parts of the world, but unfortunately many patients do not remain contact lens wearers. This paper presents the findings of the first survey on failures in contact lens wear in the Kingdom of Saudi Arabia. The purpose of the survey was to identify the reasons for failure in lens wear in the kingdom.Method: Two ... [Show full abstract] hundred previous contact lens wearers, mostly from the university population, were given questionnaires which included, among other items, demographics, length of post-fitting lens wear experience, type of lens worn and reasons for discontinuing lens wear. Data from questionnaires were analysed and presented.Results: Data from questionnaires revealed that 61 per cent of the subjects discontinued contact lens wear due to discomfort, followed by inconvenience of lens care regimen (30.5 per cent), poor vision (5.5 per cent), economy (two per cent) and refractive surgery (one per cent). The length of post-fitting lens wear experience before discontinuation ranged from two to 36 months. The majority had been soft contact lens wearers.Conclusion: The majority failed in contact lens wear due to lens discomfort and the inconvenience of lens care systems. Identification of the reason for failure in contact lens wearers is crucial if refitting is to be considered. This will aid in the selection of the appropriate lens or lens care regimen suitable to the patient and serve as a guide in the prevention of failures in prospective contact lens wearers.)Clin Exp Optom 1996; 79: 6: 255–259)

Presentation

Full-text available

KERATOCONUS INCIDENCE AMONG YOUNG PEOPLE

June 2012

Dragica Kosec

Introduction: Keratoconus is a relatively rare corneal disease, its impact on vision and overall lifestyle. When it affects very young children can lead to the development of amblyopija. Vision correction in the early phases is often possible with eyeglasses and contact lenses. In the intermediate phases specialized contact lenses are often necessary to provide good vision and physical tolerance. ... [Show full abstract] As keratoconus progresses and reaches its later phases, corneal surgery including transplantation may be required. By carefully monitoring the progression of Keratoconus and applying the necessary treatment options it is possible to help patients maintain good vision and functioning. Metods: Contact lens department on University eye clinik Ljubljana was administered 198 keratoconus patients born in 1985 and younger. We evaluated the age of onset of keratoconus. Results: The youngest patient was 3 years of age. Patients were divided into five groups by age (A :0-5, B :6-10, C :11-15, D :16-20, E :20-27). The group A will have 3 patients, in group B 27 patients, in the group C will contain 60 patients, in the group D will contain 75 patients and in the group E 33 patients. Conclusion: Keratoconus is a disease of relatively low prevalence that rarely results in blindness, but because it affects young adults, the magnitude of its public health impact is disproportionate to its prevalence. Because of its young onset it has impact on detection and presense of amblyopia and later treatment of it.

Article

Evaluation of Vision Correction Alternatives for Myopic Adults

April 1997 · Interfaces

G. Mark Brown

Prior to 1980, eyeglasses and contact lenses were the only widely available corrective treatments for myopia, commonly known as nearsightedness. In recent years, surgical procedures such as radial keratotomy (RK) and photorefractive keratectomy (PRK) have become viable corrective alternatives for myopic adults. I developed a decision model that a myopic adult can use to periodically revisit his ... [Show full abstract] or her decision regarding vision correction, given the expected costs, benefits, and risks of the surgical and nonsurgical alternatives. I exercised this decision model using my own personal values, and found that although the expected outcomes of the surgeries are already preferable to the perpetual use of external corrective lenses, my best nearterm decision was to delay surgery and give the surgeons a chance to further improve their success rates.

Article

Defects in disposable contact lenses compromise ocular integrity

February 1992 · International Contact Lens Clinic

To ascertain the prevalence of defects in disposable contact lenses, an Optimec JFC contact lens analyser (× 16 magnification) was used to examine 150 Acuvue, 150 NewVues, and 150 SeeQuence lenses, all −3.00D in power. The percentage of each lens type found to be defective was: Acuvue 75%, NewVues 5%, and SeeQuence 9%. A single-center, simultaneously-controlled, double-masked, randomized study ... [Show full abstract] was conducted to determine whether such defects compromise ocular integrity. Each of 29 subjects wore a defective Acuvue lens in one eye and a non-defective Acuvue (control) lens in the other eye on an extended-wear basis for one week. Lenses with defects visible to the naked eye were excluded. Although there was no significant difference in vision, subjective sensation, or bulbar conjunctival hyperemia between eyes wearing defective vs. control lenses, a significantly greater ocular response was observed in eyes wearing defective lenses in the form of corneal epithelial microcysts (p = 0.04), corneal staining (p = 0.02), and conjunctival staining (p = 0.04). Two cases of peripheral corneal infiltrates were observed; both cases were unilateral and occurred in eyes wearing defective lenses. Such compromise may predispose the eye to more serious complications such as infection and corneal ulceration.