Concordance between results of optic disc tomography and high-pass resolution perimetry in glaucoma

To evaluate concordance between results obtained with the Heidelberg Retina Tomograph (HRT) (Heidelberg Engineering GmbH, Heidelberg, Germany) and those obtained with the high-pass resolution perimeter (HRP) in glaucoma diagnosis.

A total of 217 patients from the glaucoma services at St. Erik Eye Hospital, Stockholm, Sweden (n = 107) and Sahlgrenska University Hospital, Göteborg, Sweden (n = 110) were included in the study. All patients were examined because of known or suspected glaucoma in at least one eye. The conventional indices presented by the instruments were used, i.e., glaucoma index from the HRT (negative values = abnormal, positive = normal) and combined deviation (upper normal limit 2.1 dB) from the HRP.

The concordance regarding the classification of normal or glaucomatous by the two instruments was 71% (153/217 eyes). The HRT indicated glaucoma but HRP findings were normal in 47 patients, and the reverse occurred in 17 patients. There was a significant difference in optic disc area between patients with abnormal HRT findings and normal HRP findings and in patients with normal HRT findings and abnormal HRP findings. The concordance could not be improved by adjusting for disc size. The correlation between combined deviation on HRP and the HRT glaucoma index was r = -0.53.

A significant correlation was found between the combined index given by HRP and the HRT glaucoma index in 217 patients examined for known or suspected glaucoma. Discordant findings were observed in 64 patients; in 22 this discordance was explained by the influence of disc size. No other reasons for differences in examination results could be detected.