Abstract
Purpose :
To evaluate the feasibility of in vivo imaging of the sclera using spectral-domain optical coherence tomography (SD-OCT) in normal guinea pigs.
Methods :
Nineteen pigmented guinea pigs with an age of 3-4 weeks were included in the study. Under general anesthesia, all animals underwent sonographic measurements of the axial length using an A/B scan and OCT imaging of the posterior ocular segment. At study end, the animals were sacrificed and the eyes of 10 animals were histopathologically examined. We measured the scleral thickness on the OCT images and upon histomorphometry. The reproducibility of the measurements was additionally assessed.
Results :
On the OCT images, the sclera was presented as hyperreflective signals beneath the choroid. The scleral thickness measured ear the optic nerve head (mean: 105.7 ± 23.1 μm) was not significantly correlated with axial length (Pearson correlation coefficient r=0.02, P=0.40). A high correlation was found for the comparison of intra-observer measurements of scleral thickness (intraclass correlation coefficient (ICC)=0.92, 95% CI: 0.86-0.96; P<0.001), and a high agreement was present for the inter-observer reproducibility (r=0.99; P<0.001). The Bland-Altman plots showed that 7.9% (3/38) of the points were located outside of the 95% limits of agreement. The scleral thickness as measured on the OCT images was significantly higher than that the values obtained by histomorphometry (116.0 ± 26.0 μm versus 77.6 ± 13.4 μm; P=0.002), with a low correlation coefficient (r=0.07).
Conclusions :
Our study shows the feasibility of SD-OCT for in vivo imaging of sclera in guinea pigs with an acceptable intra-observer repeatability and inter-observer reproducibility. This technique provides support for examining the role of the sclera in ocular disorders in studies involving guinea pigs.
This is a 2021 ARVO Annual Meeting abstract.