Keratometry and axial length in pigment dispersion syndrome: a descriptive case-control study

Pigment dispersion syndrome and pigmentary glaucoma are characterized by loss of pigment from the posterior surface of the iris due to reverse pupillary block. This may be due to an anomalous relation between the position of the globe within the orbit, the axial length of the globe, and the corneal curvature. The authors compared axial length, keratometry, and exophthalmometry in patients with pigment dispersion syndrome and pigmentary glaucoma and in healthy controls.

Thirteen pigment dispersion syndrome and pigmentary glaucoma and 17 controls underwent refraction, keratometry, A-scan and exophthalmometry. Patients with pigment dispersion syndrome and pigmentary glaucoma were selected in a university glaucoma practice, and controls were selected for their age and refraction from the staff of the hospital. Both groups were comparable in age and refraction.

Mean age of pigment dispersion syndrome patients and healthy controls was 46.54 and 41.82 years (P = 0.30), respectively, and mean refraction (spherical equivalent) was -4.53 and -4.32 diopters, (P = 0.84), respectively. No statistical differences were noted in axial length measured with A-scan (25.98 and 25.14, P = 0. 15) or anterior chamber depth and lens thickness. The pigment dispersion syndrome and pigmentary glaucoma group had flatter keratometry than the myopic controls. Mean keratometry was 42.39 +/- 1.77 and 44.34 +/- 1.50 (P = 0.003), respectively.

The results show that patients with pigment dispersion syndrome have flatter keratometry of approximately 2 diopters compared with age-matched myopic controls. This finding suggests a difference in architecture of the anterior segment.