Abstract
Purpose:
To investigate the ability of an injectable hyaluronic acid-based hydrogel to control myopia progression in a guinea pig model.
Methods:
A low modulus hyaluronic acid (HyA) hydrogel was synthesized from acrylated HyA and acrylated HyA conjugated to the cell-binding peptide bsp-RGD(15), and crosslinked with an enzymatically-degradable peptide crosslinker. For in vivo assessment of myopia-control efficacy, guinea pigs were first form deprived with diffusers (FD) for 1 week, then implanted with ~50 ul hydrogel by a sub-Tenon’s capsule injection at the posterior pole of the eye. Following surgery, the diffusers were refitted and worn for an additional 3 weeks, for a total treatment time of 4 weeks. Two control groups were included: one group received sham injections only, while the other group wore diffusers for 4 weeks with no injections. Ocular length and refraction were monitored throughout the study, with intraocular pressure (IOP), retinal morphology (Optical Coherence Tomography, OCT), and retinal function (flash electroretinograms, ERG) assessed at the end of the study. After these measurements, the animals were euthanized and the eyes were processed for histology.
Results:
Refraction and ocular length data indicate that the hydrogel treatment can significantly slow the progression of myopia in guinea pigs. The change in interocular refraction (treated-fellow control) at the end of the treatment was -1.50 ±0.44 D for the FD+HyA group and -4.86 ±1.01 D for the FD group (p<0.05); change in interocular ocular lengths were -0.01±0.06 mm and 0.17±0.04 mm for the FD+HyA and FD groups respectively (p<0.01). The IOPs of HyA-treated eyes were lower than those of their fellows, albeit not significantly so. ERG recordings were similar for HyA-treated and fellow eyes (as indicated by magnitudes of a- and b-waves and photopic negative response), and OCT revealed no obvious changes in retinal architecture. Follow-up histology verified that the hydrogel was still present 3 weeks post-surgery, with significant cell migration and collagen deposition in the implant.
Conclusions:
These data provide proof of principle that a biomimetic hyaluronic acid-based hydrogel can control myopia progression, without adverse effects to ocular health, and importantly, retinal function.
Keywords: 605 myopia •
708 sclera •
687 regeneration