SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Optometry and vision science : official publication of the American Academy of Optometry

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There is increasing interest in fitting children with soft contact lenses. This review collates data from a range of studies to estimate the incidence of complications, specifically corneal infiltrative events and microbial keratitis, in patients under the age of 18 years.

Concepts: The Age, Cornea, Orthokeratology, Contact lens, Keratitis, Corneal ulcer, Bausch & Lomb

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Horizontal peripheral prisms for hemianopia provide field expansion above and below the horizontal meridian; however, there is a vertical gap leaving the central area (important for driving) without expansion. In the oblique design, tilting the bases of both prism segments toward the horizontal meridian moves the field expansion area vertically and centrally (closing the central gap) while the prisms remain in the peripheral location. However, tilting the prisms results also in a reduction of the lateral field expansion. Higher prism powers are needed to counter this effect.

Concepts: The Central, Celestial coordinate system, Vertical integration, Singapore River

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PURPOSE: The prevalence of refractive errors in children has been extensively researched. Comparisons between studies can, however, be compromised because of differences between accommodation control methods and techniques used for measuring refractive error. The aim of this study was to compare spherical refractive error results obtained at baseline and using two different accommodation control methods-extended optical fogging and cycloplegia-for two measurement techniques-autorefraction and retinoscopy. METHODS: Participants included 25 school children aged 6 to 13 years (mean age, 9.52 ± 2.06 years). The refractive error of one eye was measured at baseline and again under two different accommodation control conditions: extended optical fogging (+2.00DS for 20 minutes) and cycloplegia (1% cyclopentolate). Autorefraction and retinoscopy were both used to measure the most plus spherical power for each condition. RESULTS: A significant interaction was demonstrated between measurement technique and accommodation control method (p = 0.036), with significant differences in spherical power evident between accommodation control methods for each of the measurement techniques (p < 0.005). For retinoscopy, refractive errors were significantly more positive for cycloplegia compared with optical fogging, which were in turn significantly more positive than baseline; whereas for autorefraction, there were significant differences between cycloplegia and extended optical fogging and between cycloplegia and baseline only. CONCLUSIONS: Determination of refractive error under cycloplegia elicits more plus than using extended optical fogging as a method to relax accommodation. These findings support the use of cycloplegic refraction compared with extended optical fogging as a means of controlling accommodation for population-based refractive error studies in children.

Concepts: Refraction, Measurement, Ophthalmology, Myopia, Cycloplegia, Refractive error, Retinoscopy, Eye care professional

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Disability glare induced by headlights of oncoming cars has been associated with reduced quality of vision. This study aimed at developing the Rostock Glare Perimeter to quantify dysphotopsia effects under simulated realistic conditions.

Concepts: Headlamp

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PURPOSE: Demodex folliculorum and Demodex brevis are ectoparasites with an astounding prevalence of 100% in patients aged 70 years and older. Every person in this age group is estimated to carry a colony of 1000 to 2000 mites. With such a high prevalence, little attention has been paid to the mite among eye care practitioners. We demonstrate a clinical sequence in a set of case reports to identify the mite. The clinical sequence includes a clinical history of blepharitis, dry eyes, and/or ocular allergy; slit lamp examination of cylindrical dandruff; and confirmation using light microscope evaluation of epilated lashes. CASE REPORTS: Patient 1 was a 68-year-old woman who demonstrates associations with dry eyes and diabetes. Patient 2 was a 44-year-old man with uncommonly seen D. brevis present. Patient 3 was a 40-year-old woman with dry eyes and allergy, showing mite tails protruding from base of lashes. Patient 4 was a 60-year-old woman who demonstrates the association with rosacea. Patient 5 was a 53-year-old woman intermittently taking topical steroid and antibiotic combination medications, with an actual mite photographed on the surface. CONCLUSIONS: Following a clinical sequence helps identify Demodex, the underdiagnosed, undertreated, and underappreciated ocular surface disease.

Concepts: Medicine, Medical terms, Topical, Mite, Slit lamp, Demodex, Demodex folliculorum, Demodex brevis

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PURPOSE: The primary purpose of this pilot study was to compare epithelial barrier function (EBF) and staining in a small group of participants using a silicone hydrogel (SH) lens worn on a daily basis with two different care regimens. Secondarily, the aim was to see if there was any correlation between corneal staining and EBF. METHODS: The corneal EBF of 10 non-lens wearers (control) and 15 age-matched asymptomatic SH contact lens wearers (test) were assessed using fluorophotometry. Biomicroscopy was performed to assess corneal staining after the EBF was measured. The lens wearers wore PureVision (FDA group V) SH lenses for two consecutive 1-month periods while using either Alcon Opti-Free Express or Renu Fresh using a randomized, investigator-masked, crossover design. Control subjects were assessed on one occasion, and lens wearers were examined before fitting with lenses and after 7, 14, and 28 days of lens wear, with each combination. RESULTS: Compared with the control group, both study groups had an increase in epithelial permeability at baseline (p ≤ 0.04). There were no changes in EBF during the treatment period for either solution (p = 0.87). A significant difference in EBF was found between the test groups during the treatment period (p = 0.02), with greater permeability in the Renu Fresh-disinfected lenses. There was poor correlation between corneal staining and EBF (r = 0.35, p > 0.05) because of large individual variations. CONCLUSIONS: Daily wear of highly oxygen-permeable SH lenses increases corneal epithelial permeability to fluorescein probably because of increased mechanical effects. In addition, certain lens-solution interactions can add to this effect, as seen in this study. Despite having a low amount of central corneal staining in the Renu Fresh group, staining and EBF did not prove to be well correlated. The presence of central corneal staining is a confounding factor when measuring EBF.

Concepts: Assessment, Cornea, Contact lens, Contact lenses, Novartis, Wear

27

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

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PURPOSE: Anecdotal evidence suggests that some sunglass users prefer yellow tints for outdoor activities, such as driving, and research has suggested that such tints improve the apparent contrast and brightness of real-world objects. The aim of this study was to establish whether yellow filters resulted in objective improvements in performance for visual tasks relevant to driving. METHODS: Response times of nine young (age [mean ± SD], 31.4 ± 6.7 years) and nine older (age, [mean ± SD], 74.6 ± 4.8) adults were measured using video presentations of traffic hazards (driving hazard perception task) and a simple low-contrast grating appeared at random peripheral locations on a computer screen. Response times were compared when participants wore a yellow filter (with and without a linear polarizer) versus a neutral density filter (with and without a linear polarizer). All lens combinations were matched to have similar luminance transmittances (∼27%). RESULTS: In the driving hazard perception task, the young but not the older participants responded significantly more rapidly to hazards when wearing a yellow filter than with a luminance-matched neutral density filter (mean difference, 450 milliseconds). In the low-contrast grating task, younger participants also responded more quickly for the yellow filter condition but only when combined with a polarizer. Although response times increased with increasing stimulus eccentricity for the low-contrast grating task, for the younger participants, this slowing of response times with increased eccentricity was reduced in the presence of a yellow filter, indicating that perception of more peripheral objects may be improved by this filter combination. CONCLUSIONS: Yellow filters improve response times for younger adults for visual tasks relevant to driving.

Concepts: Better, Improve, Probability theory, Evidence, Sunglasses, Polarizer, Photographic filter, Neutral density filter

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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

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PURPOSE: Although a great variety of pediatric tests of visual acuity exist, few have been compared directly within the same patients or have been evaluated directly against an adult gold standard. METHODS: Right eyes from 80 3- to 5-year-old preschoolers were tested at 3 m with the two current pediatric optotype tests-the Patti Pics and the Lea Symbols (Mass VAT versions)-that best adhere to the international standard for early eye and vision screening. For comparison, right eyes from 52 adults were tested under the same conditions with both pediatric tests and with a gold standard Mass VAT Sloan letter test. RESULTS: Compared with the Patti Pics, both children and adults showed relatively better and finer levels of visual acuity with Lea Symbols (0.07-0.11 logMAR better). Compared with Sloan letters, adults' acuity was also 0.09 logMAR better with the Lea Symbols but was virtually identical and also showed good statistical agreement with Patti Pics acuity. CONCLUSIONS: Although both pediatric tests show excellent testability, our data suggest that acuity values obtained with the Patti Pics optotypes are more consistent with those obtained with a gold standard visual acuity test used for older children and adults.

Concepts: Eye, Visual perception, Visual acuity, Ophthalmology, Snellen chart, Lea test, Optotype, Optotypes