Comparison of distance visual acuity measurement between dynamic optotype and LogMAR E charts

Objective

To investigate if the dynamic optotype is comparable with conventional logarithm of the minimum angle of resolution (LogMAR) optotype.

Methods

This is a cross-sectional study investigating visual acuity measurement with two methods.The study lasted for 6 months from May to November 2017.One hundred and fifty subjects (150 right eyes) with age (58.7±14.3) years were recruited in the Optometry Clinics of the School of Optometry, The Hong Kong Polytechnic University.Habitual distance visual acuity of each eye was measured with a 3-meter LogMAR E chart and a Dyop^® acuity chart displayed on a monitor placed at 6 meters, respectively.Subjects were asked to comment on the Dyop^® system regarding the overall speed and ease of understanding the test using a 5-point Likert scale.The agreement between the two charts was assessed.This study was approved by an Ethics Committee of The Hong Kong Polytechnic University (No.HSEARS20170215006) in accordance with the Declaration of Helsinki, and written information consent was obtained from all the subjects prior to any ocular examination.

Results

The mean difference between the LogMAR E chart and Dyop^® system was (0.05±0.07) LogMAR units, and the 95% limits of agreement was -0.09 to 0.19.The intra-class correlation coefficient of the two methods was 0.957.In general, 70% (105/150) of the subjects considered the Dyop^® system fast and 81% (121/150) easy to understand.

Conclusions

Visual acuity measured by the Dyop^® system is comparable to the traditional LogMAR E chart.

Visual acuity; Optotype; Dynamic acuity test; Consistency