Vascular changes in the posterior eye segment of secondary angle-closure glaucoma: cause or consequence?

BACKGROUND

To study the role of choroidal and retinal vessels in the pathology of secondary angle-closure glaucoma.

METHODS

DBA/2NNia and non-glaucomatous C57BL/6J mice over the age range 2-20 months were investigated. Corrosion cast preparations of the vasculature were studied using scanning electron microscopy. Whole mounts of the retina and choroid were stained enzyme-histochemically for NADPH diaphorase as an indicator for nitric oxide synthase activity. Semi- and ultra-thin sections of the posterior eye segment were performed and evaluated.

RESULTS

DBA/2NNia mice showed loss of choroidal pigmentation and a decrease in choriocapillary density already at 4 months of age. In animals 9 months and older, a decrease of choroidal NADPH-diaphorase positive nerve fibers was evident. The retinal vasculature showed only mild changes in NADPH-diaphorase staining, even in the oldest animals. The ultrastructural appearance of the retinal vessels was similar in both mouse strains and for all ages investigated.

CONCLUSIONS

Choroidal changes in the DBA/2NNia mouse are similar to that seen in other glaucoma models. The lack of retinal vasculature changes in adult and senescent DBA/2NNia mice suggests a normal blood supply of the retina during the progress of secondary angle-closure glaucoma in these animals.