Optic disc and visual field progression in ocular hypertensive subjects: Detection rates, specificity, and agreement

PURPOSE. To examine the detection rates, specificity, and agreement between visual field (VF) progression and Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, GmbH, Heidelberg, Germany) rim area (RA) progression in subjects with ocular hypertension (OHT). METHODS. One hundred ninety-eight OHT and 21 control subjects were examined prospectively (1994-2001) with regular Humphrey VF (Carl Zeiss Meditec, Inc., Dublin, CA) and HRT testing. Point-wise linear regression (PLR) of sensitivity/time was used to assess VF progression, using standard and three-omitting (less stringent and stringent) criteria. The change in HRT-detected progression was assessed by linear regression of sectoral RA/time, defined as slope > 1%/year, with significance level tailored according to series variability. Less stringent and stringent criteria were tested. Specificity was estimated by the proportions of control subjects with disease progression and significantly improving subjects (all). Agreement between disc and field progression in the subjects with OHT was assessed with specificities matched for both VF and HRT. RESULTS. Specificity for VF PLR was estimated to be 85.7% to 95.4% when standard criteria were used, and for RA/time to be 88.1% to 90.5% with the less-stringent criteria. In this comparison, 21.2% progressed by RA alone and 20.2% by VF alone, and 12.1% progressed by both RA and VF. Specificity was estimated to be 95.2% to 98.2% for both VF PLR and RA/time, using the three-omitting criteria and the stringent RA/time criteria, respectively. In this comparison, 8.6% progressed by RA alone, 15.1% by VF alone, and 3.5% by both RA and VF. CONCLUSIONS. A relatively high frequency of detected disease progression was observed with either method, with progression by VF occurring at least as frequently as progression by RA. Poor agreement between RA and VF progression was observed regardless of the specificity of the progression criteria. The results indicate that, in patients with ocular hypertension, monitoring of both VF and optic disc is necessary, as agreement between optic disc and VF progression is the exception rather than the rule.