Abstract
Purpose :
In cross sectional studies, it has been reported that a thinner choroidal thickness is associated with myopia. However, it is unclear whether the choroidal thinning is the result of myopia or the risk factor for myopia. The purpose of the current study is to determine whether choroidal thickness is a risk factor for myopia development in a school based longitudinal study.
Methods :
The Gobi Desert Children Eye Study was a school based 3-year cohort study. The students underwent structured questionnaire and comprehensive ocular examinations both at baseline and follow-up studies, including best-corrected visual acuity, noncontact tonometry, cycloplegic refraction, optical coherence tomography of the macular and optic disc with enhanced depth imaging method (Spectralis, Heideberg, Germany). Subfoveal choroidal thickness was measured using the embedded software. Only the right eye was selected for statistical analysis. Logistic regression model was used to analyze the risk factors for myopic progression and incident myopia.
Results :
862 students (446 boys, 51.7%) with a mean age of 10.3 (range 6-18) years at baseline completed both the baseline and follow-up examinations. Choroidal thickness was significantly thinner in eyes with myopia at baseline (275.2±50.1 vs. 298.4±43.4µm, P<0.001). Among those without myopia at baseline, the 3-year cumulative incidence of myopia was 35.3%. Incident myopia was significantly associated with subfoveal choroidal thickness at baseline (P=0.14). Myopia progression of greater than -1.5 diopters (-0.5 diopters per year) during the 3 years was detected in 50.1% eyes with myopia at baseline. In multivariate analysis, myopia progression greater than -1.5 diopters was significantly associated with baseline subfoveal choroidal thickness after adjusting age, gender and ethinicity. The myopia progression was not significantly associated with intraocular pressure and outdoor activity time.
Conclusions :
While subfoveal choroidal thickness in schoolchildren is not associated with incident myopia, a thinner subfoveal choroidal thickness predicts myopia progression in myopic eyes.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.