Background Scleral cross-linking is a potential method to inhibit axial elongation of the eye, preventing the progression of pathological myopia. Formaldehyde releasers, which are common preservatives found in cosmetics and ophthalmic solutions, have been shown to be not only effective in cross-linking corneal collagen in vitro and in vivo, but also have minimal toxicity effects on the eye. The present study aims to evaluate the efficacy of scleral cross-linking using sodium hydroxymethylglycinate (SMG) to inhibit eye growth using an in vivo rabbit model.
Methods A cross-linking solution containing 40 mM SMG was delivered to the sub-Tenon’s space behind the equator. The application regimen included a two-quadrant injection performed five times over 2 weeks on New Zealand White rabbits (n=5, group 1), and one-time injection followed for up to 5 days on Dutch-Belted rabbits (n=6, group 2). Group 1 was monitored serially for axial length changes using B-scan ultrasound for 5–6 weeks. Group 2 was injected with a higher viscosity solution formulation. Both groups were evaluated for thermal denaturation temperature changes of the sclera postmortem.
Results Axial growth was limited by 10%–20% following SMG treatment as compared with the untreated eye. Thermal denaturation analysis showed increased heat resistance of the treated eyes in the areas of injection. Overall, the SMG treatment inhibited eye growth with few side effects from the injections.
Conclusions Cross-linking solutions delivered via sub-Tenon injection provide a potential method for limiting axial length growth in progressive myopia and could be used as a potential treatment for myopia.
- sclera and episclera
- eye (globe)
Data availability statement
Data are available upon reasonable request. Data are available upon reasonable request from corresponding authors.
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Contributors QVH designed experiments and data collection tools, monitored data collection, wrote the statistical analysis plan, cleaned and analysed the data, and drafted and revised the paper. QW designed experiments and monitored data collection, and revised the draft paper. DCP monitored data collection, was the project coordinator, wrote and revised the draft paper. YYC cleaned the data, did the statistical analysis, drafted and revised the paper. RS monitored data collection, did instrumental imaging and data analysis, and revised the paper. TN was the animal project coordinator, monitored data collection, revised and drafted the paper. SLT monitored data collection, drafted and revised the paper. MZ is a guarantor, designed experiments and data collection tools, monitored data collection, wrote the statistical analysis plan, cleaned and analysed the data, and drafted and revised the paper.
Funding Supported in part by: a Research to Prevent Blindness grant to the Columbia University Department of Ophthalmology, and National Institutes of Health Grants, NEI R01EY020495 (DCP), NEI P30 EY019007 and NCRR UL1RR024156.
Competing interests Patents issued through Columbia University: US Patent Nos. 8,466,203; 9,125,856; 10,105,350; and 10,292,967.
Provenance and peer review Not commissioned; externally peer reviewed.
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