Mapping structural damage of the optic disk to visual field defect in glaucoma

PURPOSE: To evaluate the relation between the location of focal visual field defects and optic disk damage in eyes with glaucoma by short wavelength automated perimetry and confocal scanning laser ophthalmoscopy. METHODS: In 14 patients (14 eyes) with open-angle glaucoma, focal optic disk damage, and focal visual field loss, we obtained visual fields with short-wavelength automated perimetry. The short wavelength automated perimetry visual field was divided into 21 zones, representing retinal nerve fiber layer arcuate bundles. Test points were compared with a normative database. The optic disk was assessed with a confocal scanning laser ophthalmoscope, Optic disk measurements were calculated in 10-degree sectors and compared with a normative database using a new measure, the rim area ratio, which adjusts for individual differences in disk size. RESULTS: The mean number (+/-SD) of damaged visual field zones was 3.9 (+/-1.9), and the mean number of damaged rim sectors was 5.0 (+/-2.9). Focal defects on the optic disk and on short-wavelength automated perimetry were topographically related with specific damaged visual field zones corresponding to specific damaged rim sectors. CONCLUSIONS: In patients with open-angle glaucoma with focal optic disk damage and focal visual field loss, defects in optic disk and short-wavelength automated perimetry are topographically related. The rim area ratio can be used to identify focal optic nerve defects.