Abstract
Purpose: :
Spectral Domain Optical Coherence Tomography (SD-OCT) is increasingly used for macular pathology. For glaucoma, its use is promising but yet unclear. We wanted to compare the image quality between images of the macula (Mac) and of the optic nerve head region (ONHR) in both glaucomatous and healthy eyes.
Methods: :
The RTVue (OptoVUE, inc.) and Spectralis (Heidelberg Engineering, inc.) SD-OCT devices were used to obtain three-dimensional images of both the ONHR and Mac in 29 glaucomatous and 19 healthy eyes. Of both devices, the proprietary quality-indices were used to quantify image-quality. Both glaucomatous and healthy subjects did not have other proven ocular or systemic diseases. We used paired and unpaired t-tests to evaluate differences within and between groups, respectively.
Results: :
In glaucomatous eyes, the mean quality-score of the images of the ONHR was significantly lower than in those of the Mac in both the RTVue (44.3 [SD 6.0] and 49.8 [SD 6.4]; p-value 0.00) and the Spectralis (23.8 [SD 3.2] and 26.3 [SD 5.2]; p-value 0.019). In healthy eyes, we found a similarly significant difference (RTVue: 49.2 [SD 6.3] and 54.9 [SD 5.8]; p-value 0.008; Spectralis: 25.1 [SD 3.6] and 27.6 [SD 3.7]; p-value 0.015). In the RTVue, the image quality scores were significantly higher for healthy eyes than for glaucomatous eyes (49.2 [SD 6.3] vs 44.3 [SD 6.0] on ONHR and 54.9 [SD 5.8] vs 49.8 [SD 6.4] on Mac, respectively; p-values <0.01); for the Spectralis, we found no significant difference in the quality scores between healthy and glaucomatous eyes (25.1 [SD 3.6] vs 23.8 [SD 3.2] (p-value 0.23) on ONHR and 27.6 [SD 3.7] vs 26.3 [SD 5.2] (p-value 0.33) on Mac).
Conclusions: :
The quality of SD-OCT images is lower around the optic nerve head than in the macula in both glaucomatous and healthy eyes. In the RTVue, healthy eyes yield better images than glaucomatous eyes. These data suggest that the technical requirements of SD-OCT be higher for glaucoma than for macula imaging.
Keywords: imaging/image analysis: clinical • optic disc • macula/fovea