A customised portable LogMAR chart with adjustable chart illumination for use as a mass screening device in the rural population.

ABSTRACT

AIM: To develop a customised, portable, cost-effective (logarithmic minimal angle resolution) LogMAR chart with adjustable illumination for use as a mass vision-screening device in the rural population. MATERIALS AND METHODS: Visual acuity of 100 individuals was evaluated with a customised chart and compared with the standard Early Treatment Diabetic Retinopathy Study (ETDRS) chart and Snellen's Chart. Bland and Altman analytical techniques were used for analysis. RESULTS: Test-retest variability of the customised chart was just a one-line difference (95% CI for agreement), and so were the results with the standard ETDRS charts; a variability of 3-line was noted with Snellen's chart. Two-line differences were observed when comparison was made with Standard ETDRS chart and 2 to 3-line differences with Snellen's chart. CONCLUSION: The customised portable LogMAR chart with adjustable illumination shows less test-retest variability and better agreement with standard ETDRS chart; therefore, it can be used as a mass vision-screening device in rural settings.