Abstract
Purpose :
Repeatable and accurate measurements of peripheral refraction are vital in assessing relative peripheral refractive error (RPRE) as an investigative tool for clinical myopia research. A prospective, repeatability and accuracy study was accomplished on a slit-scanning ophthalmoscope and an open-field autorefractor.
Methods :
Cycloplegic refraction was measured along the horizontal meridian at 10°, 20°, and 30° temporally/nasally in 6 subjects (6 eyes) with a distribution of central spherical equivalents (-12.00D to -0.38D; mean: -6.13D). Peripheral refraction measurements were acquired using a 90° widefield slit-scanning ophthalmoscope (CLARUS™ 500, ZEISS, Dublin, CA) with prototype software, and a Grand Seiko WAM-5500 autorefractor (Grand Seiko Co., Ltd, Hiroshima, Japan). The ophthalmoscope measured vertical vergence by the displacement of 2 slits projected through upper and lower sections of the pupil. For the autorefractor, the vertical component was extracted from sphere, cylinder and axis values. One operator measured each eye; up to 5 repetitions on the ophthalmoscope and 3 repetitions of up to 10 measurements on the autorefractor per test location. RPRE was computed as the difference between means of peripheral refraction for each device and central refraction. Repeatability of each system was assessed with a test-retest standard deviation (TRT-SD), and device accuracy was evaluated with a Pearson correlation and Bland-Altman analysis.
Results :
Intra-subject repeatability was observed using 3 repeats per device with a TRT-SD at each location (Figure 1). A Pearson correlation and Bland-Altman analysis showed agreement between both devices increasing with smaller eccentricities (Figure 2). Acquiring measurements on the ophthalmoscope required only a single shot image capture, which was considerably faster than the autorefractor, which required measurements at each location.
Conclusions :
Repeatability was higher at each test location for the ophthalmoscope compared to the autorefractor. Accuracy as assessed by correlation and agreement of RPRE of both systems was demonstrated. A slit-scanning ophthalmoscope can be a useful device in assessing RPRE, which could be valuable in myopia research and clinical study development.
This is a 2020 ARVO Annual Meeting abstract.