SECTOR-BASED ANALYSIS OF OPTIC-NERVE HEAD SHAPE-PARAMETERS AND VISUAL-FIELD INDEXES IN HEALTHY AND GLAUCOMATOUS EYES

Purpose: To evaluate the correlations between the sector optic nerve h ead parameters measured by Heidelberg Retina Tomograph (HRT, Heidelber g Engineering, Heidelberg, Germany), version 1.11S, and the visual fie ld. Methods: One eye was randomly chosen from 55 individuals with glau coma and 50 healthy individuals. Each participant had at least one Hum phrey visual field, program 30-2 (Humphrey Instruments, San Leandro, C A, U.S.A.), and three 10 degrees HRT pictures. From the mean of the th ree HRT pictures, global measurements, superior (45 degrees-135 degree s), nasal (135 degrees-225 degrees), inferior (225 degrees-315 degrees ), and temporal (315 degrees-45 degrees) sector measurements were calc ulated for the following parameters: disc area, effective area, area b elow reference, mean height of contour, volume below surface, volume a bove surface, volume below reference, volume above reference, and thir d moment. From the visual field results, mean deviation (MD), superior MD, and inferior MD were calculated. For each HRT parameter we calcul ated the ''r'' Pearson correlation with the corresponding visual field measures. Results: Within the combined healthy and glaucomatous group s we found highly significant (p < 0.001) correlations between the fol lowing HRT parameters and the visual field MD: inferior and mean hight of contour (r = -0.53), inferior and third moment (r = -0.52), global and third moment (r = -0.49), inferior and volume above reference (r = 0.47), superior and third moment (r = -0.46), and superior and area below reference (r = -0.44). Correlations between global mean deviatio n and nasal or temporal sector parameters were generally smaller and l ess significant. Conclusions: inferior and superior HRT sector paramet ers were correlated with the respective visual field indices. In many cases these correlations were as strong or stronger than with the glob al equivalent shape measures.