Method for Quantitative Analysis of Vitreoretinal Adhesion in Ex Vivo Model.

Abstract

PURPOSE: Posterior vitreous detachment (PVD) is implicated in numerous retinal pathologies. A necessary step in developing new therapies, an area of significant interest, is a quantifiable assessment of posterior vitreous adhesion (PVA) that is also clinically relevant. METHODS: A 23-gauge vitrector was used at varying levels of vacuum to attempt PVD induction in a porcine eye model injected with either balanced salt solution (BSS) (control) or plasmin (2, 3, or 5 U), which can pharmacologically induce PVD. RESULTS: The average minimum vacuum necessary to induce a PVD was 395 ± 28 mm Hg for BSS alone, 385 ± 58 mm Hg for 2 U of plasmin, 265 ± 53 mm Hg for 3 U of plasmin, and 145 ± 28 mm Hg for 5 U of plasmin. We demonstrated a dose-dependent response curve with increasing amounts of plasmin, leading to a statistically significantly lower minimum vacuum necessary to induce a PVD except between BSS and 2 U plasmin. CONCLUSIONS: A dose-dependent relationship between plasmin concentration and PVD was demonstrated. We believe that this model offers significant benefits over prior work as it minimizes confounding manipulations and offers a quantitative assessment that is translatable to in vivo surgical models. TRANSLATIONAL RELEVANCE: This is the first methodology to quantitatively assess the degree of vitreous adhesion in situ.