Multiple ciliary body cysts and secondary glaucoma in the Great Dane: a report of nine cases.

Between 1989 and 1995 nine Great Danes were presented to the small animal clinic of the University of Zurich Teaching Hospital with glaucoma and multiple cysts in the anterior and posterior chamber. In four of the nine dogs cysts were present in both eyes; however, bilateral glaucoma was seen in one case only. Mean intraocular pressure (IOP) at initial presentation was 42 mmHg measured by applanation tonometry. With the exception of one dog, all animals were treated medically for a minimum of 13 days. Two animals were subsequently lost to follow up. Two dogs underwent evisceration with implantation of a silicone prosthesis. The glaucomatous globe was enucleated in three dogs. One owner declined surgery and the dog remained buphthalmic with a poorly controlled IOP. One animal remained visual after trans-scleral diode laser cyclophotocoagulation. Histopathology of the three enucleated globes showed multiple cysts originating from the ciliary body epithelium. The mechanism of IOP elevation is probably by anterior displacement of the iris with narrowing of the angle and collapse of the ciliary cleft. A delicate pre-iridal fibrovascular membrane was also seen in each case, which could have also contributed to the elevation of IOP. The high odds ratio of 2.23 (CI 95% 1.14, 3.99) for glaucoma and 37.01 (CI 95% 16.42, 77.81) for ciliary body cysts suggests they are both inherited in this breed. Pedigree analysis of the affected dogs failed to definitely reveal the mode of inheritance.