Characteristics of Posterior Precortical Vitreous Pockets and Cloquet’s Canal in Patients with Myopia by Optical Coherence Tomography.

Abstract

To describe the morphological features of posterior precortical vitreous pockets (PPVP) and Cloquet's Canal in patients with myopia using swept-source optical coherence tomography (SS OCT). A total of 96 eyes of 51 volunteers (range, 5-18 years) were enrolled in this study, and all individuals underwent OCT (Optovue Inc., Fremont, CA, USA) examinations. From the collected PPVPs images, the widths and heights of the PPVPs were measured, and connections between PPVPs and Cloquet's Canal were identified. The PPVPs widths and heights, width:height ratios and proportions of connections were compared among different age (5-8, 9-14, 15-18 years), axial length (AL; 21-23, 23-25, 25-29 mm) and myopia groups (hyperopia, low to moderate myopia, high myopia); the group data were analyzed to determine their relationship with myopia. PPVPs were identified in 89 of 96 eyes; 6 eyes were excluded for poor image quality. The PPVPs width was positively correlated with age, especially in the low to moderate myopia group (F = 7.715, P = 0.001). There was a significant difference in the PPVPs height between the refractive error groups in the 9 to 14 years group (F = 4.905, P = 0.005). The PPVPs width:height ratio was different among the refractive error groups in the 9 to 14 years group (F = 3.335, P = 0.041) and among the different age groups in the low to moderate myopia group (F = 6.077, P = 0.004). A total of 22 eyes (22.4%) were identified as having a connection between the PPVP and Cloquet's Canal. The connections began to increase with AL at 5 to 8 years (χ2 = 7.363, P = 0.025). PPVPs existed in most myopia patients from 5 to 18 years old. PPVPs width was positively correlated with age, especially in the low to moderate myopia group. PPVPs height decreased in the 9 to 14 years group with myopia. An imbalance in the horizontal and vertical enlargement of PPVP was the main feature in the 9- to 14-year-old group with myopia. The connections between the PPVP and Cloquet's Canal were associated with AL extension in the 5- to 8-year-old group.