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Siddiqui What is risk of pigmentary glaucoma from pigment dispersion syndrome?
Subjects and Methods
The study was done in two parts: assessment of the probability of converting from
pigmentary dispersion syndrome to pigmentary glaucoma, and estimation of the incidence rates
of these conditions over the 23 year period of the study.
Design: This was a retrospective study of all patients living in Olmsted County,
Minnesota diagnosed with either pigment dispersion syndrome or pigmentary glaucoma between
1976 and 1999. Patients were identified through the Rochester Epidemiology Project, a medical
records linkage system established to study the occurrence and natural history of disease among
residents of Rochester and the balance of Olmsted County, Minnesota.
8,9
It was a "community-
based" study, to distinguish it from studies of sub-specialty referral-based practices, which could
be biased by inclusion of a disproportionate number of advanced or difficult patients. This
retrospective study did not attempt to determine the prevalence of these conditions by mass
screening of the population, but rather included only patients who sought ophthalmic care. As
such, the results thus would be applicable to the care and counseling of patients seen in the
offices of ophthalmologists and optometrists, but would not necessarily apply to patients that had
never been examined.
Probability of conversion: Diagnosis of pigmentary dispersion syndrome
required two of the classic three signs: Krukenberg spindle, midperipheral radial iris
transillumination defects, and increased trabecular meshwork pigmentation in a
homogeneous "mascara line" band. Patients referred to as having "pigment dispersion
syndrome" had no glaucomatous visual field loss, no glaucomatous cupping, and no
secondary cause for pigment dispersion syndrome. Patients with pigmentary glaucoma
had the findings of pigment dispersion syndrome and two or more of the following:
