Clinical Ophthalmology (Nov 2021)
Regional Distribution of Choroidal Thickness and Diurnal Variation in Choroidal Thickness and Axial Length in Young Adults
Abstract
Muteb Alanazi,1,2 Patrick Caroline,2 Amane Alshamrani,2 Turki Alanazi,3 Maria Liu4 1Optometry Department, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia; 2College of Optometry, Pacific University, Forest Grove, OR, USA; 3School of Engineering and Applied Science, The George Washington University, Washington, DC, USA; 4UC Berkeley School of Optometry, Berkeley, CA, USACorrespondence: Muteb Alanazi Tel +966 5651227716Email [email protected]: To examine the regional distribution of choroidal thickness (ChT) and the diurnal variation in ChT and axial length (AL) over a wide range of myopic refractive error.Methods: ChT was measured in thirty-four healthy young adults (age mean ± SD: 25.2 ± 2.8, range: 18– 35 years) using spectral-domain optical coherence tomography and AL using an IOL-Master 500. Participants were divided into three refractive groups: emmetropes, myopes, and high myopes. We evaluated ChT in macular (foveal, parafovea, and perifovea) and peripheral regions (6-mm from the foveal pit) in four quadrants (superior, temporal, inferior, and nasal). To assess the diurnal variation, three measurement sessions of ChT and AL were taken at 8 AM, 12 PM, 4 PM.Results: ChT thins progressively towards the periphery. Superior and nasal quadrants exhibited the thickest (277 ± 73 μm) and thinnest (218 ± 89 μm) choroid, respectively. Higher myopic eyes showed an overall thinner choroid (237 ± 48 μm) compared to myopic eyes (264 ± 78 μm) (P 0.05).Conclusion: ChT distribution varies based on quadrant and eccentricity; superior choroid exhibited the thickest, and nasal showed the thinnest choroid. Higher myopes experience a reduced diurnal variation in ChT and AL.Keywords: choroid, diurnal variation, myopia, optical coherence tomography
