Purpose: To evaluate the relationship between time-domain and spectral domain-scanning laser ophthalmoscopy/optical coherence tomography (SD-SLO/OCT), and to compare the ability of these methods to detect glaucoma.
Methods: Forty-nine glaucoma and 43 healthy participants were imaged by SD-SLO/OCT and Stratus OCT. Bland-Altman plots were used to compare the measurements of retinal nerve fiber layer (RNFL) thickness. Areas under the receiver operating characteristics curves (AUCs), including the average thickness, thickness in each of the 4 quadrants, and thickness at each of the 12 clock-hours were compared. Sensitivity and specificity of normative classification of the 2 OCTs for detection of glaucoma were calculated.
Results: The Bland-Altman plot showed good agreement between the 2 instruments. In eyes with glaucoma, RNFL thickness was greater when measured by SD-SLO/OCT than Stratus OCT in most sectors of the eye (Average RNFL thickness: SD-SLO/OCT, 82.7±15.3 μm; Stratus OCT, 76.9±18.4 μm; P<0.001). However, the differences between 2 OCTs were not significant in healthy participants. The AUCs of average RNFL measurements for discrimination of glaucoma did not differ significantly between the instruments (SD-SLO/OCT, 0.969; Stratus OCT, 0.959; P=0.535). SD-SLO/OCT showed similar sensitivity (57.1%) with Stratus OCT (53.4%) for detection of glaucoma in normative classification of average RNFL thickness.
Conclusions: Both OCT technologies did well in the diagnosis of glaucoma. Although there were small differences in the 2 instruments in measured RNFL thickness of glaucomatous eyes, in general there was good agreement between the 2 OCTs. SD-SLO/OCT classified more glaucomatous eyes as abnormal based on its normative database.