False negative results in glaucoma detection with Heidelberg Retina Tomograph II

PURPOSE To evaluate the rate of false negative results with the Heidelberg Retina Tomograph (HRT II) in a glaucoma practice. DESIGN Cross-sectional study. METHODS We analyzed the HRTs taken between October 2002 and October 2003 in our glaucoma clinic, and selected the patients who had a good quality image (SD < 40 mu) with a normal Moorfield's Regression Analysis (MRA). A masked independent observer classified those patients as normal, glaucoma suspect, or glaucomatous on the basis of optic disc stereo photos (ODP) and at least 2 consecutive reliable automated perimetries. The diagnosis of glaucoma was based on a glaucomatous optic disc with a congruent, reproducible visual field defect. RESULTS Four hundred and fifty patients who had undergone an HRT examination were analyzed. One hundred and nine patients had an HRT classified as normal on the MRA, and a good quality image. Fifteen of those 109 patients (13.7%) were classified as glaucomatous on the basis of an abnormal ODP with corresponding visual field defect. Seven (6.4%) patients were classified as glaucoma suspect. CONCLUSION Fourteen percent of glaucoma patients with glaucoma remained undetected with the HRT II Moorfield's regression analysis as a sole means to detect glaucoma.