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Concept: Corrective lens


To compare the performance of two novel multipurpose disinfecting solutions (MPDS) in preventing silicone hydrogel contact lens dehydration, provide higher scores of subjective comfort and stable optical quality during a month of lens wear in neophyte volunteers.

Concepts: Cornea, Myopia, Lens, Contact lens, Contact lenses, Corrective lens, Intraocular lens, Oxygen permeability


Contact lens-related eye infections, which can lead to serious outcomes, including blindness, are associated with several risk factors, including sleeping in lenses, exposing lenses to water, not adhering to replacement schedules, and reusing disinfecting solution (1). In some studies, adolescent and young adult contact lens wearers have been reported to be more likely than older adult contact lens wearers to develop eye infections (2,3) and more likely to have poor contact lens hygiene practices (2). In 2015, CDC reported the number and demographics of adult contact lens wearers in the United States to define the population at risk for contact lens-related eye infections (4); however, this estimate did not include adolescents. To better understand this group of younger contact lens wearers and guide prevention efforts, a population-based survey was used to assess contact lens wear, care behaviors, risk factors, and demographics among persons aged 12-17 years (referred to as adolescents in this report), young adults aged 18-24 years, and older adults aged ≥25 years in the United States. In 2016, an estimated 3.6 million adolescents (14.5%) wore contact lenses. Of the adolescents who wore contact lenses, 85% reported at least one behavior that put them at risk for a contact lens-related eye infection, compared with 81% of young adults, and 88% of older adults. These findings can inform the creation of age-specific targeted prevention messages aimed at contact lens wearers and establish a baseline for evaluating trends in contact lens wear, care habits, and contact lens-related risk behaviors.

Concepts: United States, Cornea, Adolescence, Myopia, Lens, Contact lens, Contact lenses, Corrective lens


PURPOSE: The aim was to determine the extent of daily disposable contact lens prescribing worldwide and to characterise the associated demographics and fitting patterns. METHODS: Up to 1,000 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 performed after receiving the survey form. Survey data collected since 1996 were also analysed for seven nations to assess daily disposable lens fitting trends since that time. RESULTS: Data were collected in relation to 97,289 soft lens fits, of which 23,445 (24.1 per cent) were with daily disposable lenses and 73,170 (75.9 per cent) were with reusable lenses. Daily disposable lens prescribing ranged from 0.6 per cent of all soft lenses in Nepal to 66.2 per cent in Qatar. Compared with reusable lens fittings, daily disposable lens fittings can be characterised as follows: older age (30.0 ± 12.5 versus 29.3 ± 12.3 years for reusable lenses); males are over-represented; a greater proportion of new fits versus refits; 85.9 per cent hydrogel; lower proportion of toric and presbyopia designs and a higher proportion of part-time wear. There has been a continuous increase in daily disposable lens prescribing between 1996 and 2011. The proportion of daily disposable lens fits (as a function of all soft lens fits) is positively related to the gross domestic product at purchasing power parity per capita (r(2) = 0.55, F = 46.8, p < 0.0001). CONCLUSIONS: The greater convenience and other benefits of daily disposable lenses have resulted in this modality capturing significant market share. The contact lens field appears to be heading toward a true single-use-only, disposable lens market.

Concepts: Cornea, Myopia, Lens, Contact lens, Corrective lens, Intraocular lens, Purchasing power parity, National accounts


The aim was to evaluate the visual performance provided with a contact lens-based pinhole design against a simultaneous vision multifocal contact lens.

Concepts: Cornea, Myopia, Lens, Contact lens, Corrective lens, Book of Optics, Intraocular lens, Glasses



ABSTRACT:: Contact lens-associated corneal infiltrative events (CIEs) are presumed sterile events that have complicated contact lens wear for more than 30 years. There is consistent evidence that silicone hydrogel soft contact lenses increase CIE risk by twofold compared with low Dk hydrogel materials. The incidence of CIEs during silicone hydrogel extended wear ranges from 2% to 6% for symptomatic events and from 6% to 25% when asymptomatic events are included. For daily wear, with silicone hydrogels, the incidence of CIEs ranges from 2% to 3% for symptomatic events and from 7% to 20% when asymptomatic events are included. Despite the increased rate of CIEs with silicone hydrogels, the benefits of these lenses largely outweigh this risk for many patients. Most risk factors for CIEs observed with silicone hydrogels are consistent with CIE risk factors reported earlier with hydrogel lenses, such as bacterial bioburden on lens surfaces, and young age among others. Limiting the transfer of bacterial bioburden from the skin to lenses, lens cases and eventually to the eye is an obvious step forward for the prevention of CIEs across all lens types.

Concepts: Epidemiology, Eye, Cornea, Lens, Contact lens, Contact lenses, Keratitis, Corrective lens


Purpose: To alter the composition and structure of silicone hydrogel contact lenses to achieve controlled release of dexamethasone and evaluate the lens optical and mechanical properties compared to commercial lenses. There is a tremendous need for controlled release of drugs from ocular biomaterials as the majority of ophthalmic drugs are delivered via topical eye drops, which have low bioavailability and patient compliance. Methods: Poly(PDMS-co-TRIS-co-DMA) contact lenses were synthesized with varying PDMS/TRIS:DMA ratios (0.25:1, 0.67:1, 1.5:1) as well as with additional crosslinking monomers. Lenses were characterized via in vitro release studies in a microfluidic device at ocular flowrates and in large well-mixed volumes, optical quality studies over visible wavelengths, mechanical analysis, and determination of polymer volume fraction in the swollen state. Results: Extended and controlled release of therapeutically relevant concentrations of dexamethasone was achieved for multiple day, continuous wear up to 60 days at in vitro ocular flowrates. Release was delayed due to a combination of increased hydrophobic to hydrophilic composition and the inclusion of additional structural constraints, both of which decreased the polymer volume fraction in the swollen state. However, decreased mass release rates were at the expense of increased modulus and decreased lens flexibility. All lenses had high optical clarity (∼90% transmittance) and contained highly oxygen permeable siloxane composition similar to those found in commercial silicone hydrogel lenses, but they had poor flexibility for use as soft contact lenses. Conclusions: Based on our results, the lenses described herein likely have too high of a modulus for use as extended-wear, soft contact lenses with drug release. Therefore, other controlled release methods would be better suited for maintaining adequate mechanical properties and achieving controlled and extended release for the duration of wear in soft, silicone hydrogel contact lens biomaterials. However, these biomaterials may find clinical use as more rigid gas permeable contact lenses or inserts.

Concepts: Polymer, Cornea, Lens, Contact lens, Contact lenses, Corrective lens, Visible spectrum, Rigid gas permeable


PURPOSE: To investigate the relationship between parental refractive error and the nearwork-induced transient myopia (NITM) characteristics of their children. METHODS: Three hundred sixty children (173 boys and 187 girls) aged 6 to 17 years were tested. Initial NITM and its decay time (DT) were assessed objectively (WAM-5500, Grand-Seiko) immediately after binocularly viewing and performing a sustained near task (5 diopters [D]) for 5 minutes, incorporating a cognitive demand with full distance refractive correction in place. The NITM was classified into three categories: low (<0.15 D), moderate (0.15 to 0.30 D), or high (≥0.30 D), whereas its decay was classified into two categories, namely, complete or incomplete. In addition, the children were divided into three groups based on the number of myopic parents (none, one, or two) and into four groups based on the level of parental myopia (no, low, moderate, or high). RESULTS: Neither paternal nor maternal refractive error was associated with either their children's initial NITM magnitude or its DT in the myopic, emmetropic, or hyperopic groups or the combined group. No significant differences (p > 0.05) in the NITM magnitude, DT, or decay time constant were found as related to the number of myopic parents or level of parental myopia. Multiple odds ratio for incomplete decay of NITM did not change significantly (p > 0.05) with either an increase in number of myopic parents or level of parental myopia. CONCLUSIONS: There was no association between parental refractive error and their children’s NITM characteristics. This suggests a primary environmental basis for the NITM characteristics in the children.

Concepts: Myopia, Lens, Corrective lens, Refractive error, Hyperopia


A cross-sectional study was undertaken in Nakuru, Kenya to assess the prevalence of refractive error and the spectacle coverage in a population aged ≥50 years. Of the 5,010 subjects who were eligible, 4,414 underwent examination (response rate 88.1 %). LogMAR visual acuity was assessed in all participants and refractive error was measured in both eyes using a Topcon auto refractor RM8800. Detailed interviews were undertaken and ownership of spectacles was assessed. Refractive error was responsible for 51.7 % of overall visual impairment (VI), 85.3 % (n = 191) of subjects with mild VI, 42.7 % (n = 152) of subjects with moderate VI, 16.7 % (n = 3) of subjects with severe VI and no cases of blindness. Myopia was more common than hyperopia affecting 59.5 % of those with refractive error compared to 27.4 % for hyperopia. High myopia (<-5.0 DS) was also more common than extreme hyperopia (>+5.0 DS). Of those who needed distance spectacles (spectacle coverage), 25.5 % owned spectacles. In conclusion, the oldest, most poor and least educated are most likely to have no spectacles and they should be specifically targeted when refractive services are put in place.

Concepts: Visual acuity, Ophthalmology, Myopia, Corrective lens, Refractive error, Hyperopia, Visual impairment, Glasses


PURPOSE: Recent research suggests multizone/dual-focus (DF) lens corrections may aid in controlling the progression of myopia. Recently, such a soft contact lens has become commercially available in Hong Kong (MiSight, CooperVision). The purpose of the current study was to evaluate the visual acceptability of this new lens design. METHODS: In a double-masked, randomized, crossover trial, 24 subjects (aged 18 to 25 years) wore MiSight contact lenses and Proclear Multifocal +2.00 diopters Add D (MF) soft contact lenses. Patient-reported outcomes (0 to 100 scale) and objective measures of visual performance were acquired for best-spectacle distance correction (BC) and with each contact lens after 1 week of daily use at HIHC (high illumination-high contrast) at distance and LILC (low illumination-low contrast) at distance, intermediate, and near. RESULTS: There were no significant differences in HIHC distance acuity between BC and either the DF or MF lens and no difference between the DF and MF lenses. However, when measured under LILC, there were significant mean differences between each study lens and BC viewed at distance and intermediate. The LILC logMAR visual acuity was not significantly different between the DF and MF lenses at any viewing distance. Although average visual quality and ghosting ratings for both DF and MF study lenses were significantly lower than habitual under all conditions, there were no significant differences between the DF and MF lenses (p = 0.448). CONCLUSIONS: Good acuity, similar to that attainable with typical MF lens correction, is attainable with a new contact lens designed to control myopia progression. However, like other contact lenses that contain multiple refractive zones, some decrease in visual performance may be experienced.

Concepts: Visual acuity, Cornea, Myopia, Lens, Contact lens, Contact lenses, Corrective lens, Glasses