Validation of an automated‐ETDRS near and intermediate visual acuity measurement

Abstract

Background

The aim of this study was to determine the repeatability of an automated‐ETDRS (Early Treatment Diabetic Retinopathy Study) near and intermediate visual acuity measurement in subjects with normal visual acuity and subjects with reduced visual acuity. The agreement of automated‐ETDRS with gold standard chart‐based visual acuity measurement was also studied.

Methods

Fifty‐one subjects were tested (aged 23 to 91-years; 33 subjects with normal visual acuity: 6/7.5 or better; 18 subjects with reduced visual acuity: 6/9 to 6/30). Near and intermediate visual acuity of one eye from each subject was measured with an automated tablet‐computer system (M&S Technologies, Inc.) and Precision Vision paper chart in a random sequence. Subjects were retested one week later. Repeatability was evaluated using the 95 per cent limits of agreement (LoA) between the two visits.

Results

Average difference between automated‐ETDRS near visual acuity and near visual acuity by paper chart was 0.02 ± 0.10 logMAR (p > 0.05). Agreement of near visual acuity between automated‐ETDRS and paper chart was good, with 95 per cent LoA of ±0.19 logMAR. Furthermore, automated‐ETDRS near visual acuity showed good repeatability (95 per cent LoA of ±0.20). Mean difference between automated‐ETDRS intermediate visual acuity and intermediate visual acuity by paper chart was 0.02 ± 0.10 logMAR (p > 0.05). Agreement of intermediate visual acuity between automated‐ETDRS and paper chart was good, with 95 per cent LoA of ±0.20 logMAR. In addition, automated‐ETDRS intermediate visual acuity had good repeatability (95 per cent LoA of ±0.16).

Conclusion

Automated‐ETDRS near and intermediate visual acuity measurement showed good repeatability and agreement with the gold standard chart‐based visual acuity measurement. The findings of this study indicate the automated visual acuity measurement system may have potential for use in both patient care and clinical trials.

Key words:

• computer
• intermediate vision
• near vision
• tablet
• visual acuity

ACKNOWLEDGEMENTS

The authors would like to thank M&S Technologies, Inc. for providing the automated tablet‐computer visual acuity system for this study. The authors also would like to thank Dr Kelly Frantz in helping edit the manuscript.

Supporting information

Additional supporting information may be found in the online version of this article at the publisher’s website:

Figure S1. Automated‐ETDRS (Early Treatment Diabetic Retinopathy Study) measurement. A: Automated‐ETDRS measurement at near in a subject. B: Automated‐ETDRS letters viewed by subjects. C: Automated‐ETDRS letters viewed by the examiner. D: An example of automated‐ETDRS at 6/6 level viewed by the examiner.