Clinical Ability of Hrt Cup Area in Detecting Glaucomatous Visual Field Defects

Abstract

Abstract: : Purpose: To evaluate the clinical ability of HRT total and sectorial cup area in detecting glaucomatous visual field defects in the clinical setting Methods: 514 patients (193 normal, 216 with OHT, 105 with POAG) were enrolled. Normal individuals (mean age 56±11 yrs) had a normal 24/II HFA visual field (VF), IOP = 22 mmHg on repeated measurements and normal VF. POAG patients (mean age 68±12 yrs) had abnormal VF (GHT "outside normal limits" and CPSD > 2dB) and IOP >= 22 mmHg. HRT examination was performed with a 10° angle view. A mean image of three repeated images was analyzed with 2.01 software. The contour line was manually traced by two of the Authors whose reproducibility has been previously tested. Standard HRT parameters have been collected. Cup area was calculated for the whole disc and for eight 45° disc sectors. One eye per patient was used for study purposes. The normative database reference population was established using the upper 99% prediction band of the regression of cup area on disc area and of each sectorial cup area on sectorial disc area in the normal group. Sensitivity and specificity were calculated by means of standard procedures. Results: Cup area showed a high regression on disc area (r = 0.76 for total cup area; r = 0.53 - 0.7 for the sectorial analyses). Sensitivity of cup area analysis in detecting glaucomatous VF defects was 81%, whereas specificity was 95%. In the OHT population total or sectorial cup area identified as abnormal 46 out of 216 patients. Pooling the normal and the OHT subjects in the "normal group", specificity resulted 86%. Conclusions: Total and sectorial cup area analysis adjusted for disc size allows to well discriminate between normal and POAG patients.

Keywords: optic disc • imaging/image analysis: clinical • visual fields