Correlation between mean visual field loss and morphometric optic disk variables in the open-angle glaucomas.

PURPOSE

To correlate morphologic changes of the optic disk with mean visual field defect in glaucoma.

METHODS

Color optic disk photographs of 302 patients with primary open-angle glaucoma, 53 patients with pseudoexfoliative glaucoma, and 55 patients with normal-pressure glaucoma were morphometrically evaluated. The data were correlated with mean visual field defect.

RESULTS

The correlation between mean visual field defect and neuroretinal rim area was similar to a logarithmic function. The visual field deteriorated slightly in the early stage and markedly in the advanced stages of glaucoma. A discrepancy between normal visual field and abnormal optic disk occurred more often in young than in old patients. Neuroretinal rim shape, total rim area, and rim area in the temporal inferior and temporal superior disk sectors correlated best with mean visual field loss. Alpha and beta zones of peripapillary atrophy and diameter of retinal arterioles were less clearly correlated. Calculated rim variables that were corrected for optic disk area did not markedly improve the correlation coefficients. In eyes with normal visual fields, rim shape was the most important disk variable for detecting glaucomatous optic nerve damage. There were no patients with glaucomatous visual field loss and an unremarkable optic disk.

CONCLUSIONS

In early glaucoma, changes are more marked in optic disk appearance than in the visual field, suggesting that at least for some patients, for early glaucoma diagnosis, optic disk appearance is more important than perimetry, whereas for follow-up examination, perimetry may be more useful than optic disk morphometry. The most useful planimetric optic disk parameters are neuroretinal rim shape and rim area.