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Keyur Savla, Viswanathan Ramasubramanian; Measurement of 360° Peripheral Refraction Profile in Emmetropic and Myopic Young Human Eyes. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1133.
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© ARVO (1962-2015); The Authors (2016-present)
Prior studies have measured refraction along the horizontal, vertical and few oblique retinal eccentricities. However, 360° peripheral refraction profiles of human eyes have not been measured. Hence, the goal of this study was to measure and compare the 360° peripheral refraction profile in emmetropic and myopic eyes.
Twenty healthy young subjects (10 emmetropes and 10 myopes) aged between 17 to 25 years were recruited. Myopic eyes had spherical refraction of ≤ -3 D and astigmatism of ≤ 2 D. Right eyes were cyclopleged with 1% cyclopentolate eye drops. Three refraction measurements in the right eye were recorded using a Grand Seiko autorefractor (WAM 5500) at each of the predetermined 185 locations across all meridians in 10° steps, spanning a total of 30° horizontal and 15° vertical visual fields. Mean values of spherical equivalent refraction (SER), J0 and J45 were measured at each eccentricity. Sector-wise comparisons were performed along 4 sectors: a) horizontal (nasal-temporal) b) vertical (superior-inferior) c) oblique (superior-temporal inferior-nasal [ST-IN]) and d) superior-nasal inferior-temporal [SN-IT] for both the groups.
In all 4 sectors, the SER for myopic eyes showed a relative hyperopic shift in the periphery, with the temporal periphery becoming almost equal to the foveal refraction at 30° eccentricity. The J0 component showed relative hyperopia in the nasal half of the retina for the first 15° and then progresses to become more myopic in the periphery for both the emmetropic and myopic subjects. The J45 component has a relatively similar outcome for both groups with the ST-IN sector being hyperopic in the periphery and the SN-IT sector being myopic in the periphery. The vertical and horizontal sectors remain relatively close to the foveal refractive error throughout the eccentricities for both the groups.
The study showed that there are significant sector-wise changes in refraction at the periphery as compared to fovea. With all the 360° meridians considered in this study, it provides a valuable insight into an eye’s complete refractive error profile.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
Sector-wise representation of the 185 predetermined locations (black and red dots) where refraction was measured.
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