Central and Peripheral Autorefraction Repeatability in Normal Eyes

Abstract

Purpose To determine the between-visit repeatability of peripheral autorefraction measurements using the Grand Seiko WAM-5500 in normal eyes. Methods Cycloplegic autorefraction of the right eye was measured on 25 myopic young adults using a modified Grand Seiko autorefractor. Measurements were made centrally (along the line of sight) and ±20°, ±30°, and ±40° from the line of sight in the horizontal meridian at two visits separated by 1 to 15 days. Five autorefraction measurements at each location were converted to vector space and averaged. Relative peripheral refraction (RPR) was calculated as the difference between the peripheral and central spherical equivalent (SE). Between-visit repeatability was evaluated by plotting the difference versus the mean of the measurements at the two visits (bias) and by calculating the 95% limits of agreement (LoA). Results The mean (±SD) age and SE refractive error centrally (at visit 1) were 24.0 ± 1.3 years and −3.45 ± 1.42 D, respectively. There was no significant between-visit bias for any refractive component evaluated (M, J0, J45, and RPR) at any location measured (all p>0.05). The 95% LoA of defocus (M) was ±0.21 D centrally and increased with increasing eccentricity to ±0.73 D and ±0.88 D at 40° nasally and temporally on the retina, respectively. The 95% LoA of RPR increased with increasing eccentricity to ±0.67 D and ±0.82 D at 40° nasally and temporally on the retina, respectively. Conclusions In normal eyes, the repeatability of cycloplegic autorefraction was best centrally and decreased as eccentricity increased; however, repeatability in the far periphery was still better than previously reported between-visit repeatability for foveal cycloplegic subjective refraction. With clear knowledge of the repeatability of on- and off-axis cycloplegic autorefraction with the Grand Seiko, peripheral measurements can be properly interpreted in longitudinal studies.

Aberrometry Repeatability and Agreement with Autorefraction

“…In our study, the repeatability of the Discovery System (±0.34 D) was found to be comparable to the repeatability of the Grand Seiko autorefractor under cycloplegic conditions in adult subjects. 6, 9, 12 …”

Clinical evaluation of the Shin‐Nippon SRW‐5000 autorefractor in adults: an update

“…Astigmatic vectors showed 40 degree nasal repeatability of ± 0.71 D and ± 0.39 D for 40 degrees temporally for J 0 , and ± 0.30 D and ± 0.36 D respectively, for these positions for the J 45 vector. The repeatability of the instrument was considered sufficient for valid use in determining peripheral defocus in studies aiming to slow the progression of myopia …”

“…Acceptable positions for alignment, at least in the horizontal meridian, would be obtained if the instrument was placed co‐incident with a point halfway between the pupil centre and the corneal reflex . Moore and Berntsen assessed repeatability of central and peripheral autorefraction measurements with the WAM‐5500 instrument in normal eyes and those treated by orthokeratology. In normal eyes, the between‐visit repeatability (defined as 1.96 × S.D.…”

“…The repeatability of the instrument was considered sufficient for valid use in determining peripheral defocus in studies aiming to slow the progression of myopia. 37 When an individual views a distant target under closedloop conditions immediately following completion of a sustained near-task, an excessive accommodative response may be induced [i.e. a lead of accommodation termed nearwork-induced transient myopia (NITM)].…”

Agreement Between Autorefraction and Subjective Refraction in Keraring-Implanted Keratoconic Eyes

“…Following the introduction of automated refraction in 1970, 1 many types of autorefractors have been described and newer devices have improved significantly in speed, accuracy, 2-6 and reliability 2,4,7,8 …”