Structural Alterations of Retinal Detachment After Intravitreal Triamcinolone Injection in Rabbit Eyes

ABSTRACT

PURPOSE: To investigate the effect of localized retinal detachment on both the detached and attached regions, and to determine the effect of triamcinolone on Muller cell gliosis. METHODS: Pars plana vitrectomy was performed in both eyes of 12 pigmented rabbits. A dome shaped retinal detachment was made by injecting sodium hyaluronate into the subretinal space. Triamcinolone (5 mg) was applied intravitreally to one eye (12 eyes). The detached retinal area and the neighboring attached region were studied by light and electron microscopy 3, 7, and 28 days after surgery. Tissues were prepared in 5 um sections for hematoxylin-eosin staining and immunohistochemistry with antibody to glial fibrillary acidic protein (GFAP). RESULTS: In addition to the well-known degeneration of photoreceptor cells in the detached retina, an incomplete but severe loss of ganglion cell axons occurs in both the detached and the attached regions. The total retinal thickness gradually decreased in the detached areas, while the thickness of the inner retinal layers remained virtually unchanged over several weeks. Gliotic alterations were apparent in both the detached and non-detached retinal areas, and intravitreal triamcinolone did not alter these gliotic alterations of Muller cells. CONCLUSIONS: It is noteworthy that progressive retinal destruction also occurs in the attached retina after local detachment. This may account for visual impairment in strikingly large areas of the visual field, even after retinal reattachment.