Does a Relationship Exist Between Posterior Vitreous Detachment, Macular Thickness and Foveal Avascular Zone Dimensions in Myopic Eyes?
Abstract Background: The posterior vitreous detachment (PVD) is a separation of the posterior vitreous cortex from the internal limiting membrane of the retina. The PVD induces several potentially serious pathologic events at the vitreoretinal interface. The aim of the study is to determine if relationships exist between PVD, macular thickness (MT) and the foveal avascular zone (FAZ) in myopic eyes. Methods: This is a retrospective case study of 63 myopic subjects who underwent comprehensive eye examination including the optical coherence tomography angiography (OCTA) between January 1 and Jun 30, 2019. The spherical equivalent (SE) was calculated using the manifest refraction. The myopia grouping was based on a severity scale, namely mild, moderate, high and very high using standard refractive error classifications. The PVD classification was based on optical coherence tomography (OCT) images. The status of the PVD and MT were evaluated with Macular Cube 200 × 200 images and the FAZ was imaged with an OCTA, Angioplex. The MT and FAZ dimensions were calculated using a custom algorithm. Results: A total of 114 myopic eyes subjects had median (range) age of 26.00 (22.00 - 28.00) years. Of this cohort, females comprised 62.3 % of the dataset, and the right eyes were 50.00 %. In this population, 10 eyes had no PVD in any quadrant, and 73 eyes had incomplete PVD in all four quadrants. The inferior quadrant had the maximum number of PVD cases and the nasal quadrant had the least number of cases. High myopic eyes exhibited significantly increased low foveal volume (p = 0.000). The inferior part of para- and perimacular area showed a significant thinning in very high myopic eyes (p = <0.05). A statistically significant alteration of FAZ circularity index found in very high myopic eyes (p = 0.002). Conclusion: In high and very high myopic eyes, an increasing trend of partial PVD is seen. The most commonly involved location was the inferior quadrant. A significant alteration in foveal volume and circularity index of the FAZ is seen in high and very high myopic eyes.