Automated versus manual refractive error measurements in domestic cats

Abstract

PURPOSE. To compare the results of streak retinoscopy (SR) vs. the Welch Allyn SureSight™ autorefractor (WASS) in normal cats and determine the appropriate WASS setting (WASSadult vs. WASSpediatric) for use in the domestic cat. PROCEDURE/DESCRIPTION. Refractive error was determined in 30 young adult domestic short haired cats (60 eyes) with normal, non-cyclopleged eyes via SR. In 28 cats (56 eyes), refractive error was also determined via WASSadult. In 8 cats (16 eyes), refractive error was also determined via WASSpediatric. Refractive error was determined by both WASSadult and WASSpediatric in 6 cats (12 eyes). Agreement between methods was evaluated with Bland-Altman analysis. Mixed modeling was used to test for difference between methods. RESULTS/OUTCOMES. Mean ± SD SR spherical equivalent (SE) was +1.05 ± 0.97 diopters (D) (n=60 eyes). Mean WASS SEadult was +0.60 ± 1.15 D (n=56 eyes), and mean WASS SEpediatric was +2.75 ± 0.98 D (n=16 eyes). The difference between methods was statistically significant for WASSadult vs. SR (p ≤ 0.001, n=56 eyes), WASSpediatric vs. SR (p = 0.01, n=16 eyes), and WASS_adult vs. WASSpediatric (p ≤ 0.001, n=12 eyes). The 95% limits of agreement for WASSadult vs. SR was (-1.80 D, +0.99 D), WASSpediatric vs. SR was (-0.75 D, +3.55 D), and WASSpediatric vs. WASSadult was (-4.75 D, +0.21 D). IMPLICATION/FUTURE DIRECTION. While there was a significant difference between methods, the level of agreement between SR and WASSadult for measurement of refractive error in the adult domestic cat is reasonable. For WASS, adult setting is recommended for clinical use. Supported in part by the Center for Companion Animal Studies at Colorado State University. None.