Age, gender, corneal diameter, corneal curvature and central corneal thickness in Nigerians with normal intra ocular pressure

AbstractPurposeTo investigate the relationship between age, gender, corneal diameter, central corneal curvature, central corneal thickness (CCT) and intraocular pressure in Nigerians with normal intraocular pressure.MethodsOne hundred and thirty eyes from 130 subjects (mean age=47.8±16.8 years) including 77 males and 53 females were recruited. CCT was measured by ultrasound pachymetry, intraocular pressure was determined by non-contact tonometry, horizontal and vertical corneal diameters were measured with a ruler and central corneal curvature was measured by keratometry.ResultsThe mean values obtained were as follows: CCT=548.97±34.28μm, IOP=15.61±2.69mmHg, average corneal curvature (AVK)=42.98±1.19 D, horizontal corneal diameter (HVID)=11.39±0.69mm and vertical corneal diameter (VVID)=10.51±0.50mm. There was a significant effect of age on CCT (r=−0.35, p<0.001). A 10-year-increase in age was associated with a 7.0μm decrease in CCT. Males had significantly wider HVID than females (p=0.03). Subjects in older age groups have narrower HVID and VVID. Corneal curvature, corneal diameter and gender did not significantly affect CCT.ConclusionCCT of normotensive Nigerian adults decreases with increasing age. There was no correlation between CCT and IOP in normotensive subjects. CCT was not significantly influenced by gender, corneal curvature and corneal diameter

A new Gujarati language logMAR visual acuity chart: Development and validation

Aims: Gujarati is the main spoken language of a large proportion of the population of India. The aim of this study was to develop and validate a new Minimum Angle of Resolution (logMAR) visual acuity chart in the Gujarati language. Materials and Methods: A new Gujarati visual acuity chart was designed to logMAR specifications using Gujarati optotypes experimentally selected to have similar relative letter legibility under spherical and cylindrical defocus. The chart validation study was carried out using 153 adult subjects in a large clinical setting in India. Subjects who were literate in English and Gujarati participated in the study. Visual acuity was measured with the new Gujarati logMAR chart and a modified Early Treatment of Diabetic Retinopathy Study-(m-ETDRS) logMAR chart. The method of presentation was randomized between the charts. Repeat visual acuity was measured on a subsequent day with a second version of the Gujarati logMAR chart. Results: The Gujarati chart correlated highly with the m-ETDRS logMAR chart (r2 = 0.974). The mean visual acuity difference (Gujarati - m-ETDRS logMAR) was equal to three letters (-0.06 logMAR). The Gujarati logMAR chart also proved to be highly repeatable (r2 = 0.994, test-retest) with 95% CI of ± 0.04 logMAR. Conclusions: The new Gujarati logMAR visual acuity chart provides a valid and repeatable tool for the measurement of visual acuity in native Gujarati language speakers

A standardized logarithm of the minimum angle of resolution visual acuity chart in Hindi

Purpose: The purpose of this study to develop and calibrate a new Hindi logarithm of the minimum angle of resolution (logMAR) visual acuity chart. Methods: A new Hindi visual acuity chart was designed to logMAR specifications using Hindi optotypes experimentally selected to have similar relative legibility under equivalent spherical and cylindrical defocus. The chart calibration study was carried out in a large clinical setup in India. Participants who were literate in English and Hindi participated in the study. Visual acuity was measured with the new Hindi logMAR chart and a modified ETDRS (m‑ETDRS) logMAR chart. The method of presentation was randomized between the charts. Repeat visual acuity was measured on a subsequent day with a second version of the Hindi logMAR chart. Results: The Hindi logMAR chart correlated highly with the m‑ETDRS logMAR chart ( r 2 = 0.92); however, the mean visual acuity difference (Hindi logMAR‑m‑ETDRS logMAR) was nearly one and half lines (0.13 logMAR, 95% confidence interval [CI] = ±0.15 logMAR). The Hindi logMAR chart also proved to be highly repea table ( r 2 = 0.99; mean difference 0.005, 95% CI = ±0.04 logMAR). Conclusion: This study reports the first standardized visual acuity chart developed in Hindi incorporating equal letter legibility and logMAR chart design features. The Hindi logMAR visual acuity chart provides a valid and repea table tool for the measurement of visual acuity in native Hindi language speakers. Future use of the new Hindi chart should incorporate an increase in optotype size of 0.13 logMAR

Aberration control and vision training as an effective means of improving accommodation in individuals with myopia

Purpose.: To test the efficacy of a novel dual treatment for improving accommodative accuracy and dynamics in young persons with myopia. Methods.: Ninety-three young persons with myopia (mean spherical equivalent, −3.0 ± 1.8 D; age 16.8 ± 2.1 years; spherical aberration +0.06 ± 0.04 μm) participated in the study. Custom-designed soft contact lenses were used to alter ocular SA to −0.10 μm to improve accommodative accuracy and reduce any lag of accommodation. A vision training regimen was performed for 18 minutes per day for up to 6 weeks to improve speed of dynamic accommodation. Control groups had contact lenses with no added SA and/or no exercises. To avoid any effects of natural levels of negative aberration on the results of the study, all participants who had negative SA were excluded. Results.: The treatment contact lenses produced a significant reduction in lag of accommodation (P < 0.05) at all proximal viewing distances measured. The vision training measurement and treatment resulted in a significant increase in distance facility rate for all groups compared with their own baselines (P < 0.05). Near facility rate improved in the vision training treatment group only compared with its baseline (P < 0.05). Both positive and negative response times for distant viewing were significantly shorter in all groups after training compared with their baseline values (P < 0.05). At near, the positive response times were decreased significantly (P < 0.05) in both groups, whereas the negative response times decreased significantly only in the vision training treatment group. Conclusions.: After 3 months, the dual treatments (altering SA and vision training) used in the study were effective in modifying accommodation. The static accommodative response to targets at proximal distances was increased by the altered SA contact lenses and rates of dynamic accommodation improved with vision training