Defining myopia using refractive error and uncorrected logMAR visual acuity >0.3 from 1334 Singapore school children ages 7-9 years

Abstract

Aim: To determine the association of spherical equivalent (SE) with low uncorrected visual acuity (VA) along with a proposed definition for myopia using logMAR VA .0.3 as the criteria. Methods: 1334 Chinese schoolchildren (mean age 7.8; range 7-9 years) were enrolled in the study after those who had hyperopia >+2.00 dioptres (D) and astigmatism . = 22.00D were excluded. Uncorrected logMAR VA was measured for both eyes. Cycloplegia autorefraction was achieved by the instillation of three drops of 1% cyclopentolate 5 minutes apart. The average of five successful consecutive refraction and keratometry readings were obtained with calibrated Canon RK5 autokeratorefractometers by well trained optometry students, at least 30 minutes after the instillation of the third drop of cyclopentolate. SE cut-off points (20.25D, 20.5D, 20.75D, 21.0D) were evaluated. Results: Using different SE cut-off points, the myopia prevalence rates of this sample of schoolchildren varied from 45.8% (SE at least 20.25 D) to 30.7% (SE at least 21.0 D). The cut-off point of >20.75 D had a sensitivity and specificity of 91.8% (95% CI, 89.2 to 94.4) and 93.7% (95% CI, 92.1 to 95.3), respectively, to predict low vision defined as uncorrected logMAR VA . 0.3 (either eye). The next best cutoff point of 20.5D had a higher sensitivity (93.3%), but lower specificity (87.9%). Conclusions: The cut-off points of 20.75D and 20.5D in SE refraction are appropriate for the prediction of uncorrected logMAR VA worse than 0.3, which is the criterion for the US common state adult driver licensing standard.

Myopia Is Associated With Lower Vitamin D Status in Young Adults

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Poor Vision Among China's Rural Primary School Students: Prevalence, Correlates and Consequences

“…By the convention of the ophthalmology field (Cumberland, Peckham, & Rahi, 2007;He et al, 2004), reduced uncorrected visual acuity is defined as visual acuity less than or equal to 6/12 in either eye (column 1). Reduced uncorrected visual acuity is widely used as a proxy for myopia or indicative of visual impairment (Luo et al, 2006;Tong et al, 2002;Wedner, Ross, Balira, Kaji, & Foster, 2000). Following common practice in the literature (Congdon et al, 2008;He et al, 2004He et al, , 2007, we also report visual acuity results based on the better eye.…”

Definition of high myopia by parapapillary atrophy. The Beijing Eye Study

“…The ophthalmoscopic feature of high myopia is a large myopic crescent around the optic disc because of the myopia-associated stretching of the posterior pole of the fundus. Because the lower limit of the myopic refractive error in the definition of high myopia has not been clearly defined yet (Luo et al 2006), it was the purpose of our study to assess in a population-based manner at which refractive error beta zone of parapapillary as surrogate for the highly myopic stretching of the posterior fundus starts to markedly increase in size. The answer to this question may help in detecting which eye has high myopia that is associated with a stretching of the posterior pole leading to an increased risk for an exudative myopic maculopathy and to an increased risk for glaucomatous optic neuropathy because of a stretching and thinning of the lamina cribrosa and peripapillary sclera (Xu et al 2007b).…”