Abstract
Purpose :
The trabecular meshwork serves as the main pathway for aqueous humor (AH) drainage and is the target of several IOP-lowering surgical procedures in the treatment of glaucoma. However, the intrascleral AH outflow pathway located beyond the trabecular meshwork is poorly understood due to its small size and location within the highly scattering sclera. The purpose of this study was to develop a corneoscleral rim perfusion model that allows OCT angiography (OCTA) imaging of post-trabecular AH outflow structures.
Methods :
Corneoscleral rims remaining after Descemet's membrane endothelial keratoplasty (DMEK) were used for imaging. Segment diameters were measured and a carrier was 3D printed to construct an artificial anterior chamber as recently described by Peng et al. (Exp. Eye Res., 2022). The carrier size was optimized to fit the corneoscleral rims tightly. Cyanoacrylate glue was used to attach the segments to the carrier. Microscopy analysis was conducted to assess the distribution of adhesive to prevent any potential obstruction of outflow channels due to excess glue. After preparation, the specimens were connected to a perfusion system and tested for leakage. Lipid emulsion-based OCTA was performed as previously demonstrated by our group in porcine eyes.
Results :
Twenty corneoscleral rims (mean diameter 16.68 mm, SD ± 0.27 mm) were used, with the carrier size set at 15.0 mm. Leak tests were performed on ten additional corneoscleral rims. The adhesive construction remained watertight up to a mean pressure of 88.1 cmH2O (SD ± 30.23 cmH2O). Microscopy analysis showed a mean distance of 2.27 mm (SD ± 0.37 mm) from the adhesive edge to the limbus and 1.78 mm (SD ± 0.81 mm) to the scleral spur. After perfusion of the artificial anterior chamber with a lipid emulsion-based contrast agent, post-trabecular AH outflow structures were successfully visualized with OCTA.
Conclusions :
Imaging of the intrascleral AH vessel system provides valuable insight into the anatomy and dynamics of the human post-trabecular outflow pathway. The use of remnant donor rims from DMEK preparation may allow to study large numbers of human specimen.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.