DEC 12, 2013
This prospective study found that swept-source OCT (SS-OCT) may be a more reliable option for measurement of corneal parameters than slit scanning topography.
The eyes of 41 normal and 46 keratoconus subjects were imaged first using SS-OCT and slit scanning topography and then with ultrasound pachymetry during the same visit.
The authors found that in normal eyes, central corneal thickness (CCT) measured by SS-OCT was thinner compared with slit scanning topography (P< 0.0001) and ultrasound pachymetry (P < 0.0001). Ultrasound readings had better 95 percent limits of agreement with SS-OCT than slit scanning topography. In keratoconus eyes, CCT was thinner on SS-OCT than slit scanning topography (P = 0.081) and ultrasound pachymetry (P = 0.001).
Overall, reproducibility coefficients and intraclass correlation coefficients were significantly better with SS-OCT for measurement of CCT, anterior best-fit sphere and posterior best-fit sphere (all P < 0.001).
They conclude that with shorter scan duration, better agreement with ultrasound pachymetry and smaller test-retest measurement variability, SS-OCT might be preferred over slit scanning topography for corneal thickness and elevation measurements.