Comparison of glaucoma progression evaluated with Heidelberg retina tomograph II versus optic nerve head stereophotographs

Abstract

Background: To compare disease progression in glaucoma evaluated by means of the Heidelberg retina tomograph (HRT II) or by expert clinical assessment of colour stereophotographs of the optic nerve head (ONH).Methods: One eye each of 54 subjects with glaucoma was reviewed using the HRT II and ONH stereophotographs. The ONH stereophotographs were assessed twice each for glaucomatous progression by 2 expert observers (Drs. Buys and Trope). They were considered to be in agreement if their results were the same in 3 of 4 assessments. Progression on the HRT II was defined by using the topographic change analysis (TCA). The clinical assessments were the reference standard used to determine sensitivity and specificity of the HRT II TCA.Results: The expert observers were in agreement in 50 subjects (92%). Concordance between the HRT II and ONH stereophotographs assessments was obtained in 35 patients (65%); 16 patients (30%) showed progression on HRT II only, while 3 patients (6%) showed progression on stereophotographs only. When these results were used to perform a post hoc analysis, HRT II sensitivity increased from 70% to 78% and specificity increased from 63.6% to 70%. The positive predictive value of the HRT II rose from 30.4% to 47.8%, while the negative predictive value remained at 90.3%.Interpretation: Our results demonstrate only fair agreement between HRT II and clinical judgment of ONH stereophotographs for progression in glaucomatous eyes. At present, HRT II progression alone should not indicate a treatment change. HRT II change must be evaluated in conjunction with other clinical features of deterioration before altering therapy.