Purpose
To compare of image quality between swept source optical coherence tomography (SS-OCT) and spectral domain OCT (SD-OCT) according to various ocular media opacity
Methods
20 healthy eyes without media opacity and 40 eyes with media opacity (20 eyes with cataract, 15 eyes with vitreous opacity, 5 eyes with corneal opacity) were included in this study. All subjects performed same scan protocol (6x6 mm macular scan) of both SD-OCT and SS-OCT sequentially. For the comparison of image quality, a total of 120 OCT images were subjectively graded by two trained retina specialist using qualitative OCT image grading system (0-9) suggested by previous report. In addition, we measured image quality factor (Q-factor) of all OCT images provided by each OCT device for objective assessment.
Results
The image quality of SS-OCT was better than that of SD-OCT in both healthy eyes and the eyes with medial opacity, which was statistically significant in both subjective (7.79 vs 2.91) and objective (106.82 vs 32.49) assessment (P<0.05). Regardless of the type of media opacity, SS-OCT showed better image quality than SD-OCT. In cases with healthy eyes, there was no statistical difference in subjective interpretation between two OCT devices. In cases with severe media opacity, SD-OCT did not show detailed microstructure of retina such as external limiting membrane and photoreceptor layer, while SS-OCT did clearly.
Conclusions
Recently introduced SS-OCT used longer wavelength light source than SD-OCT, which may lead to good image quality in eyes with media opacity. SS-OCT may be useful in the evaluation of retinal disease in cases with severe media opacity.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)