Abstract
Purpose :
This study is aimed at investigating the effect of scleral crosslinking (SXL) using sub-Tenon’s injections of genipin in tree shrews eyes with normal visual experience.
Methods :
Five injections of 0.4 mL of genipin at 0 mM (sham) and 20 mM were performed in one eye while the fellow eye was considered as control. Injections were carried out over 15 min every other day starting at 18 days of visual experience (DVE). Tree shrews were randomly assigned into 3 experimental groups: normal visual experience without any injections (n=6), with 5 x sham injections (n=6) and with 5 x genipin injections at 20 mM (n=6). Daily measurements of axial dimensions and the refractive state were performed in awake animals between 18 DVE and 35 DVE. A mixed-design repeated measures ANOVA model was used to test for mean differences in axial dimensions and refractive state between the different groups.
Results :
Compared to the normal group, the sham injection group showed a significant reduction in vitreous chamber depth and axial length (p<0.05). Compared to the sham group, genipin injected eyes showed significant corneal thickening and a significant reduction in anterior chamber depth, vitreous chamber depth and axial length (p<0.05). Surprisingly, the refractive state was not significantly different between any of the tested groups.
Conclusions :
We have shown that scleral crosslinking using genipin can alter the development of axial dimensions in a normal tree shrew eyes. We have shown that sub-Tenon’s sham injections reduce the vitreous chamber depth. This effect is increased when genipin is used. In contrast to sham injections, SXL also impacted the development of the anterior chamber depth and corneal thickness. The observed corneal swelling in the genipin group might have caused changes in corneal curvature, which counteracted the reduction in axial length and kept the refractive state unchanged. Further optimization of the genipin delivery approach is needed to reduce the effect of scleral crosslinking on the anterior segment of the eye.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.