gms | German Medical Science

Scanning Laser Tomography with the Heidelberg Retina Tomograph (HRT) is well established in the analysis and follow-up of the optic disc configuration in glaucoma patients. With the Stratus OCT a new instrument for optic disc topography, based on optical coherence tomography has become available. Therefore, we compared optic disc analysis and retinal nerve fiber layer thickness measurements by OCT with HRT as the "gold standard".

41 eyes of 21 patients with suspected or manifest glaucoma were included in the study. In each eye optic disc analysis was performed with the Stratus OCT (3 repeat measurements) and the HRT (3 repeat measurements). In addition, a peripapillary scan of the retinal nerve fiber layer was done with the Stratus OCT (3 repeat measurements). The central 30 degree visual field was documented with the Octopus 101 perimeter, program G2. The mean visual field defect (MD) was analysed. Neuroretinal rim area (RA), cup/disc area ratio (CDA) and mean retinal nerve fiber layer thickness (RNFL) were compared between OCT and HRT.

The RA measured 1.190±0.42 mm² (range 0.30-2.00 mm²) with the OCT and 1.48±0.37 mm² (range 0.79-2.49 mm²) with the HRT. The CDA was 0.53±0.20 (range 0.06-0.92) for the OCT and 0.42±0.16 (range 0.05-0.74) for the HRT. RA and CDA correlated well between both imaging techniques with correlation coefficients of r=0.85, p<0.0001 and r=0.74, p<0.0001 respectively. The RNFL thickness correlated less between OCT and HRT with a correlation coefficient of r=0.54, p=0.0003. The Correlation between both imaging techniques on the one hand and visual field MD on the other was relatively poor (correlation coefficient range 0.37-0.43).

In our sample of 41 eyes with and without glaucomatous field damage OCT and HRT proved to be equally suitable for the analysis of optic disc topography.