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

Abstract

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. 目的 研究动态视标(Dyop®)与LogMAR视力表检测视敏度的一致性。 方法 采用横断面研究方法，纳入2017年5—11月在香港理工大学视光学院视光门诊检查的健康受试者150人150眼，均取右眼进行观察，平均年龄(58.7±14.3)岁。所有受试者均分别接受距离3 m的传统LogMAR E视力表和在距离6 m的监视器上Dyop®视力表的远视力测定，测定后受试者采用5分Likert量表对Dyop®视力测定速度和易度进行评分。对2种视力表视力测定结果的一致性进行评估。 结果 LogMAR E视力与Dyop®视力平均差值为(0.05±0.07)LogMAR，2种方法的95%一致性界限为-0.09～0.19。2种方法测定视力的组内相关系数为0.957。70%(105/150)的受试者认为Dyop®视力测定速度较快，81%(121/150)的受试者认为测定方法容易学习。 结论 Dyop®视力测定与传统LogMAR视力测定在临床上可以互相替代。