실험적 안압변동에 따른 망막전위도 및 망막미세구조의 변화

Abstract

The purpose of this study is to compare the functional and ultrastructural changes of retina according to the level of intraocular pressure. The experiment was carried out by observing the changes of electroretinogram and electronmicroscopic findings of retina in rabbits which were divided into 4 groups according to the elevated intraocular pressure level. Intraocular pressure (lOP) was adjusted by means of gravity by changing the height of saline bottle which was connected to vitreous via an infusion needle and manometer. From the experiments, following findings were obtained. 40mmHg group: "B" wave was abolished within 11,.......13 hours after elevation of lOP, so as "a" wave within 18~24 hours in 7 rabbits, but "b" wave remained until 36 hours after elevation of lOP in 3 other rabbits. In all cases no significant ultrastructural changes were demonstrable. 60mmHg group: "B" wave was abolished within Zt,.......3 hours and "a" wave within 5,.......6 hours after elevation of lOP respectively. Ultrastructurally, slight flattening of pigment epithelium started to appear, being accompanied with fragmentation of the outer segments. 80mmHg group: "B" wave was abolished within If,.......2 hours and "a" wave within 3 hours after elevation of lOP, respectively. Ultrastructurally, moderate flattening of pigment epithelium and moderate edema of inner segments were observed. 100mm Hg group: Electroretinogram was totally abolished within 10 minutes after elevation of rop. Ultrastructurally, marked flattening of pigment epithelium with marked distension of basal infolding were observed. It is of authors' assumption that: 1. the functional changes of retina start prior to the ultrastructural alterations following acute elevation of rop and the degree of severity manifests in proportion to the level of rop, and 2. the retinal ultrastructural changes develop at the level of 60mmHg of rop, and undergo irreversible changes at the level of 80mmHg or more of IOP.