The Process of Wound Healing of the Avascular Outer Layers of the Retina

Abstract

The process of wound healing of the avascular outer layers of the retina is studied on a series of Laser lcsions of the monkey, Ccrc.oliitl/fr.ilt;~~~~.~ uelhio/).s. T h e extent of the retinal lesions is limited to thc pigment epithelium and photoreceptor cells, whereas Bruch's membrane anti the vascular inner layers of the retina remain intact. The retinal lesions arc not seen to be invaded by cells from the chortiid. nor from the retinal vessels. During the first three days after irradiation the pigment epithelial cells in a zone, about 7 5 pin wide. around the lesions appear to be changcd into bi-or multinucleate cells with thc additional nuclei situated in apical cytoplasmic protrusions which extend towards and into the lesions. During the second and third days after irradiation the lesions arc invaded by two kinds of cells which both appear to arise through the off-budding of the nucleus-containing apical protrusions of the pigment epithelial cells around the lesions: (a) phagocytic cells which disintegrate the damaged tissue and, as this process is completed 4-9 days after irradiation show cvitlence of melanogcncsis; and (b) regenerated pigment epithelium which forin a single lnycr of rells along Bruch's membrane, but show no evidc nce of phagocytosis or intracellular disintegration of the damaged tissue. Within the lesions both these kinds of cells show mitotic figures the third clay after irratliation.

Reactive Changes in the Human Retinal Pigment Epithelium in Vitro

“…Clinical and histological works have elucidated the changes following experimental induced damage to the pigment epithelium in vivo (Noell 1973;Nilsson et al 1977;Zinn & Marmor 1979;Ts'o et al 1977;Friedman & Kuwabara 1968;Bulow 1978;Armstrong et al 1978).…”

Eog Changes in Photocoagulation of Diabetic Retinopathy

“…The reduction in EOG after photocoagulation of diabetic retinopathy appears to remain at an unchanged low level, being also found 6-8 weeks after the treatment, at a time when the healing processes after photocoagulation have usually been completed as demonstrated in animal experiments by Bulow (1978). The EOG itself is due predominantly to a difference in potential over the pigment epithelium and a change in this potential during adaptation from dark to light.…”