97th DOG Annual Meeting 1999
COMPARISON OF RETINAL NERVE FIBER LAYER THICKNESS IN HEALTHY SUBJECTS MEASURED BY THE HEIDELBERG RETINA TOMOGRAMM (HRT) AND OPTICAL COHERENCE TOMOGRAPHY (OCT)
M. Klemm, M. Kohlhaas, A. Walter, G. Richard
The thickness of the retinal nerve fiber layer (RNFL) has special importance in several eye diseases such as glaucoma. This prospective study was performed to compare OCT and HRT measurements of RNFL thickness in normal eyes.
Subjects: The study included 45 eyes of 45 healthy subjects with a mean age of 48 (range: 25 - 70 years). With OCT each patient underwent circular scans around the optic nerve with a circle size of 3.37 mm. Three measurements per eye were performed. With HRT, we obtained 3 images of each eye and created a baseline image. RNFL thickness analyses were performed using a contour line within the Elschnig`s scleral ring.The median and interquartile range (IQR) values for RNFL thickness were calculated for the superior, inferior, nasal and temporal regions and for the total scan circle.
Results: The total median value of RNFL thickness in healthy persons measured with OCT was 79.9 µm (IQR 6.6 µm), measured by HRT 259,5 µm (IQR 87 µm). Differences between both techniques were similar within the single regions. A slight positiv correlation between the RNFL thickness measured by HRT and OCT could be found.
Conclusion: With regards to the scattering of biological data the OCT and HRT seem to offer a suitable method for measuring RNFL thickness.
University Eyehospital, Martinistr. 52, D-20246 Hamburg