scleral crosslinking using glyceraldehyde for the prevention of myopia progression in the rabbit: biochemical and ultrastructural changes

Abstract

Purpose : To develop and assess the efficacy of a novel scleral cross-liking method using glyceradehyde for preventing lens-induced axial elongation in New Zealand rabbits, and to investigate the biochemical and microstructural changes that occur.

Methods : Sixteen New Zealand rabbits aged seven weeks were randomly divided into three groups. Rabbits in the cross-linking (CL, n = 6) and non-cross-linking groups (NCL, n = 5) were treated with a -8.00 Diopter (D) spherical lens monocularly over the course of two weeks. Rabbits in the untreated control group (UC, n = 5) did not receive any treatment. At days 0, 2, 4, 6, 8, 10, and 12, the cross-linking effects were achieved by a Sub-Tenon’s injection of 0.15 ml 0.5 M glyceradehyde to the right eyes of rabbits in the CL group. Refractive errors and axial length (AXL) were measured on the 1^st, 7^th and 14^th days of the induction period. All animals were euthanized after two weeks, and then biomechanical testing, as well as light and electron microscopy were used.

Results : There was no significant difference in the baseline AXLs of the three groups (p = 0.622). After 14 days, the scleral cross-linking method resulted in less AXL change in the CL group (p＜0.01). Fewer large-diameter scleral fibers in the inner scleral layer when compared to the NCL group (p＜0.01). Following the cross-linking treatment, the mean ultimate stress was significantly greater in the CL group at 28.69 ± 7.52 (SD), compared to 13.53 ± 1.6 in the NCL group, and 20.48 ± 2.35 Mpa in the UC group (p ＜ 0.01); while the Young’s modulus was 1.74 ± 0.53, 0.47 ± 0.19, and 0.99 ± 0.14 Mpa, respectively (p＜ 0.01). No histological damage observed in the retina or choroid.

Conclusions : This study demonstrates that lens-induced axial elongation in rabbits can be effectively blocked by scleral cross-linking using glyceradehyde, with increased fibril diameter and an enhanced ultimate stress and Young’s modulus; with no deleterious effects observed in the retinas or optic nerves of the treated eyes.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Figure 1. Results of measurements of the refractive system:
A = anterior chamber depth; B = lens thickness; C = axial length; D = vitreous chamber depth.
Error bars represent the standard error of the mean.
CL: cross-liking, NCL: non-cross-linking, UC: untreated control.