Methodology research on peripheral refractive measurement under spectacle correction

Abstract

Objective To establish a systematic specified measurement for peripheral refraction in myopic eyes under spectacle correction. Methods A peripheral refractive measurement system was established based on the Grand Seiko WAM-5500 autorefractor. An accessory with a modified visual angle device was used to replace the headrest. A ray-tracing method was used for determining the offset of the visual field angle. Using this system and technique, peripheral refraction was measured at 7 different points at 10° intervals over the central±30° of the horizontal visual field on 35 myopic subjects under spectacle correction conditions. The same measurement for peripheral refraction was also taken on another 35 myopic subjects (control group) under uncorrected conditions by using the unmodified system. The reliability of the system and technique were analyzed by using an independent samples t -test. Results This system and technique were effective for measuring peripheral refraction in myopes under spectacle correction. The reliability of this method was in compliance with traditional methods for measuring peripheral refraction under spectacle correction (P> 0.05). Peripheral refractions were more hyperopic than that of the fovea in myopic subjects under spectacle correction. Conclusion This system and technique are effective and reliable for measuring peripheral refraction in myopic eyes under spectacle correction. Key words: Refraction measurement,peripheral; Spectacle; Autorefractor