Agreement of measurement of parapapillary atrophy with confocal scanning laser ophthalmoscopy and planimetry of photographs

Purpose: To evaluate whether parapapillary atrophy can be measured interactively using confocal scanning laser ophthalmoscopy. Methods: For 36 patients with open-angle glaucoma or suspected of having glaucoma, confocal scanning laser ophthalmoscopy of the optic nerve head was performed using the Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany). Alpha and beta zones of parapapillary atrophy were plotted independently by two examiners on HRT images before and after reviewing optic disc photographs. These data were compared with planimetric measurements obtained from analyzing the disc photographs. Results: Before viewing the disc photographs, assessment using the HRT images correlated better with the beta zone than alpha zone planimetric measurements. If the HRT images were evaluated while simultaneously viewing disc photographs, correlation coefficients increased for both examiners 1 and 2. Interobserver and intraobserver reliability were 0.431 and 0.802, respectively, for alpha zone, and 0.882 and 0.948, respectively, for beta zone. Conclusion: Parapapillary atrophy can be estimated with confocal scanning laser ophthalmoscopy. Correlation with planimetric measurements is best if conventional optic disc photographs are simultaneously viewed. Intraobserver and interobserver reliability are higher for beta zone than for alpha zone.