Optic disc area in different types of glaucoma

To evaluate the possible relationship of optic disc area with retina nerve fiber layer in different glaucoma subtypes.

One eye each was chosen from 45 patients with ocular hypertension, 45 patients with primary open angle glaucoma, 45 patients with pseudoexfoliation glaucoma and 45 healthy controls followed in our hospital. The records of the patients were reviewed retrospectively. Optic disc area and circumpapillary retina nerve fiber layer measurements were obtained using optical coherence tomography. Central corneal thickness was measured by ultrasound pachymetry.

The median disc area in the patients with primary open angle glaucoma was significantly higher than the patients with ocular hypertension (2.19 vs 1.90 mm(2), P=0.030). The median retina nerve fiber layer was thinner in the patients with primary open angle glaucoma and pseudoexfoliation glaucoma than the patients with ocular hypertension for superior, inferior and temporal quadrants. After adjustment for age, no difference in central corneal thickness was found between the groups. Greater disc area was associated with thicker retinal nerve fiber layer for superior, inferior and nasal quadrants in the patients with primary open angle glaucoma. There was no correlation between disc area and central corneal thickness measurements of the groups.

Disc size affects the retinal nerve fiber layer thickness in eyes with primary open angle glaucoma and is a possible risk factor for glaucomatous optic nerve damage.