Correlations between morphologic measurements of the optic disc using planimetric tests and changes in the visual field in patients with glaucoma

PURPOSE: To evaluate the relationships between planimetrical measurements of the optic disc and visual field indices in primary open-angle glaucoma patients and glaucoma suspects. MATERIALS AND METHODS: Materials consisted of 64 patients (128 eyes) divided into two groups: glaucoma suspects without any treatment (30 patients, 60 eyes) and early open-angle glaucoma patients already medically treated (34 patients, 68 eyes). All the patients underwent the full, computerized, planimetrical analysis of the optic disc. A special attention was paid to the neuroretinal rim measurements. Visual field examination was performed with automated perimeter Octopus 101 using test dG2. Results were analysed with the use of "Interzeag Peridata" software. RESULTS: We found the statistically significant correlations between neuroretinal rim area and visual field parameters in the glaucoma group. The highest relationship concerned mean defect and compound index of the field. There were no such correlations in glaucoma suspects. Cup/disc ratio correlated more weakly with visual field than neuroretinal rim area. We also analysed mean and extreme values of the neuroretinal rim area in groups of different depth and configuration of visual field defects. CONCLUSIONS: Neuroretinal rim area is a more valuable planimetrical parameter in optic disc analysis than cup/disc ratio. It is also an important factor affecting the visual field, but probably not the only one. There is a significant correlation between visual field quantitative parameters and neuroretinal rim area in primary open-angle glaucoma patients, but in glaucoma suspects that is not true. Digital planimetry proved to be a valuable tool for optic disc biomorphometry and it seems to be an objective method for detecting development of structural changes in glaucoma.