Morphologic features of degeneration and cell death in the neurosensory retina in dogs with primary angle-closure glaucoma.

Objective: To investigate cellular death in the neurosensory portion of the retina during the first 7 days after onset of clinical signs of overt primary angleclosure glaucoma (PACG) in dogs.

Sample Population: 14 globes from dogs with PACG and 2 normotensive globes from dogs with PACG in the opposite eye.

Procedures: Retinas were examined via light microscopy and terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick end-labeling.

Results: Necrosis of ganglion cells and segmental degeneration of the nerve fiber layer rapidly progressed to scattered full-thickness retinal attenuation and disorganization. Apoptosis was detectable within 1 day after onset of PACG and was prominent by 3 days. Necrosis of ganglion cells was significantly greater in retinas affected for < or = 1 day, compared with retinas affected for > 1 day. In contrast, apoptosis in the ganglion cell layer was significantly greater in retinas affected for > 1 day, compared with retinas affected for < or = 1 day. End-stage retinal atrophy was seen by day 7.

Conclusions And Clinical Relevance: The presence of necrotic ganglion cells within 1 day after onset of clinical signs suggests a narrow window of opportunity to initiate effective therapy in overt PACG. Photoreceptor death is an important and striking aspect of neurosensory retinal degeneration after acute onset of PACG.