Observation of posterior precortical vitreous pocket using swept-source optical coherence tomography

Abstract

Purpose: To observe posterior precortical vitreous pockets (PPVPs) using swept-source optical coherence tomography (SS-OCT).

Methods: We performed SS-OCT in both eyes of 58 volunteers (36 men, 22 women) using 12-mm horizontal vertical scans through the macula and optic disc. To minimize age-related changes (liquefaction or posterior vitreous detachment), all subjects were a mean of 26.2 years (range, 22-40 years). The refractive errors ranged from -9.5 diopters (D) to +3.0 D. To estimate the PPVP size, we measured the height between the fovea and the anterior border of the PPVP and the maximal width in the 12-mm horizontal scan through the fovea and disc.

Results: SS-OCT visualized the PPVPs as boat-shaped lacunae in the macular area bilaterally in all subjects (maximal width, 3114-9887 μm; mean width, 6420.6; central height, 208-1877 μm; mean height, 708.1 in the right eyes, with no significant difference in the left eyes). There was a significant correlation between the PPVP height and myopic refractive error. The posterior wall of the PPVP was a thin vitreous cortex, thinnest at the fovea. The septum was between the nasal border of the pocket and Cloquet's canal, which extended forward and tilted superiorly in all cases. A channel connected Cloquet's canal and the PPVPs bilaterally in 54 (93.1%) of 58 cases.

Conclusions: SS-OCT clarified the boat-shaped PPVP structure in vivo. Although the central height increased with the myopic refractive error, the width was unchanged. A channel connecting Cloquet's canal and PPVP suggested the route of aqueous humor into the PPVP.

Keywords: Cloquet's canal; channel; posterior precortical vitreous pocket; swept-source optical coherence tomography; vitreous humor.