Effect of Myopic Defocus on the Retina and Choroid and Its Interaction with Defocus Regions, Diurnal Rhythm, and Accommodation.

Purpose: To explore the effect of defocus region and amount, diurnal rhythm, and accommodation on myopic defocus-induced changes in the retina and choroid. Design: Four test lenses were used: single-vision soft contact lens (SVCL), bifocal spectacle lens (BSL) with +3.50 diopters (D) addition in the inferior visual field, defocus incorporated multiple segments lens (DIMS), and dual-focus contact lens (DFCL) with +2.00 D addition. Participants: Twenty-one adults aged between 18 and 30 years, myopia between -1.00 D and -6.00 D, were included. Methods: Four lenses were used in random order at 4 separate days for each participant. Participants underwent OCT and OCT angiography examinations after distance-viewing (4 m) and near-viewing (20 cm) for 20 minutes with 4 test lenses at both 10 am and 5 pm. Main Outcome Measures: Retinal and choroidal thicknesses (RT and ChT) and vessel density were assessed. Results: The changes in RT, retinal and choroidal vessel density were not significantly different between lenses or times (all Conclusions: Myopic defocus inhibited choroid thinning more effectively in the morning, and provided sufficient defocus in the superior retina was more effective. The amount of lens defocus in this study (+3.50 D) was insufficient to inhibit choroidal thinning with 5 D accommodation completely. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.