Sensitivity and Specificity of the Heidelberg Retina Tomograph II Version 3.0 in a Population-based Study: The Tajimi Study

Abstract

To evaluate the sensitivity and specificity of the 3 glaucoma classification programs, the FS Mikelberg discriminant function (FSM), Moorfields Regression Analysis (MRA), and Glaucoma Probability Score (GPS) of version 3.0 of the Heidelberg Retina Tomograph (HRT) II (Heidelberg Engineering, Dossenheim, Germany), in a population-based setting for the first time. Population-based cross-sectional study. One randomly chosen eye of each subject without glaucoma, subject with glaucoma, and subject with suspected glaucoma with reliable HRT II measurements from the Tajimi study (2297 eyes of 2297 subjects) were included for analysis. Glaucoma was diagnosed by the optic disc and visual field findings according to the criteria of the International Society of Geographical and Epidemiological Ophthalmology. The sensitivity and specificity of FSM, MRA, and GPS were calculated. Characteristics of erroneously diagnosed glaucoma (false-negative) eyes and factors that influenced specificity with the 3 programs were investigated. Sensitivity and specificity of FSM, MRA, and GPS. Sensitivity and specificity varied significantly among the 3 programs: 59.1%, 39.4%, and 65.2% (P = 0.02 approximately 0.003, chi-square test), and 86.7%, 96.1%, and 83.0% (P<0.0001) with FMS, MRA, and GPS, respectively. MRA gave the lowest sensitivity but the highest specificity. Positive predictive values for these programs ranged between 0.10 and 0.23, whereas negative predictive values ranged between 0.98 and 0.99. False-negative eyes had significantly better visual field indexes (P<0.01 approximately 0.002, Mann-Whitney U test) and smaller cup and larger rim parameters compared with true-positive glaucoma eyes. Older age and hyperopia were negatively correlated with the specificity of GPS but not with that of FMS and MRA. Larger disc area was significantly associated with decreased specificity of all programs. In a population-based setting, the sensitivity of the HRT II was unsatisfactory with any of the classification programs, whereas specificity was satisfactory. A significant percentage of the glaucoma discs were labeled as normal, and eyes in the earlier stage of the disease appear to be more likely to be misdiagnosed as normal. Factors such as age, refraction, and disc area had an influence on specificity, but the degree of its influence was different for each classification program.