Pigment Dispersion Syndrome With and Without Glaucoma

Pigment dispersion syndrome (PDS) is not an uncommon ocular condition and is frequently associated with myopia. There is loss of pigment from the posterior iris, seen clinically in most cases as iris transillumination with pigment deposited on the corneal endothelium, iris surface and on the angle structures overlying Schlemm's canal. In a subset of patients ocular hypertension or glaucoma may develop.

Ocular hypertension is defined as 3 separate measurements of the intraocular pressure greater than 22 mm/Hg in the absence of visual field loss. Glaucoma is defined as the presence of a characteristic field defect (Bjerrum scotoma, nasal step or arcuate scotomas) with intraocular pressures greater than 22 mm/Hg measured sometime during a diurnal curve testing.

The etiology of this condition is not known. Hypotheses include developmental abnormalities of the iris dilator muscle or mechanical rubbing of zonules against the iris, resulting in pigment dispersion in the anterior chamber and pressure elevation. PDS is then viewed as a variant of primary open-angle glaucoma or may be secondary to pigment deposited in the angle structures with secondary damage to the trabecular meshwork. A hereditary component does appear to play a role in the PDS syndrome and may also predispose to the development of glaucoma.

The purpose of this study is to evaluate and determine the risk factors that differentiate patients with PDS, PDS+OH, or PDS+GL by documenting the ophthalmic findings and following their clinical course. In order to do this, diagnostic tests including intraocular pressure and visual fields will be performed. This data may make it possible to determine the risk of patients having PDS of developing OH, GL or other possibly associated findings such as retinal detachment or cataract. In addition, patients with "pigmentary glaucoma (PG)" will be compared to those with the known characteristics of primary open-angle glaucoma (POAG) to determine whether PG is different than or a variant of POAG. When possible, family members will be examined to investigate the inheritance pattern of this syndrome and its relationship to POAG.