Screening for myopia and refractive errors using LogMAR visual acuity by optometrists and a simplified visual acuity...

Area of Science:

• Ophthalmology
• Pediatric Optometry
• Public Health Screening

Background:

• Refractive errors are common in schoolchildren, necessitating effective screening methods.
• Current widespread screening in Singapore uses simplified charts, but their accuracy is debated.
• The Early Treatment Diabetic Retinopathy Study (ETDRS) chart offers a more rigorous approach to visual acuity assessment.

Purpose of the Study:

• To compare the sensitivity and specificity of simplified acuity charts versus the ETDRS chart for screening refractive errors in Singaporean schoolchildren.
• To determine optimal cutoff values for detecting myopia and any refractive error using both screening methods.

Main Methods:

• A population-based study involving 1779 schoolchildren in Singapore.
• Visual acuity was measured using both a simplified 7-line chart by nurses and a modified Bailey-Lovie (logarithm of the minimum angle of resolution - logMAR) chart by optometrists.
• Receiver-operating characteristic (ROC) curves were analyzed to evaluate the diagnostic performance of each method.

Main Results:

• The simplified chart's optimal threshold for detecting myopia or any refractive error was 6/12 or worse.
• logMAR visual acuity thresholds were 0.26 for myopia and 0.18 for any refractive error.
• The logMAR method demonstrated significantly greater area under the ROC curves, indicating superior accuracy for detecting myopia and refractive errors.

Conclusions:

• Visual acuity screening using the ETDRS method is more accurate than simplified charts for detecting myopia and refractive errors in children.
• The findings suggest a need to re-evaluate current screening protocols for improved accuracy in pediatric populations.