Corneal collagen crosslinking (CXL) with riboflavin and UVA has been successful in preventing keratoconus progression and corneal warpage, and new research suggests this technique also shows promise in myopia. Through animal studies, an investigative team from China found that the modified CXL procedure may potentially help control the pathologic process of myopia, even though further investigation into its safety is necessary.1
CXL with riboflavin-UVA is a minimally invasive procedure without allograft material implantation, which makes it possible to reduce complications such as infection and rejection, the researchers explained. “Its effectiveness, stability and safety make it hopeful to arrest progressive myopia or to inhibit the over-expansion of the sclera,” they wrote in their paper.1
One study in the review used white rabbits as a model. The right eyes underwent CXL using riboflavin and UVA radiation, and every quadrant had either two or six scleral irradiation zones. The eyelids of the right eyes were sutured after therapy to establish myopia. Outcomes showed that CXL with riboflavin and UVA effectively prevented occlusion-induced axial elongation and that the size of the treatment area was effective.2
Another investigation established a lens-induced myopia model in guinea pigs to develop methods of CXL for the treatment of progressive myopia. The results indicated that CXL using riboflavin and UVA irradiation effectively prevented the progression of myopia by increasing scleral biomechanical strength. Additionally, scleral collagen fiber arrangements of the crosslinked eyes were denser and more regularly distributed than the myopic eyes.3
More recent studies have investigated the effect of oral administration of riboflavin combined with whole-body UVA irradiation on the biochemical and biomechanical properties of the sclera in a lens-induced myopic guinea pig model. This technique appeared to increase the strength and stiffness of the sclera by altering the biochemical and biomechanical properties and resulted in greater decreases in axial elongation and myopic diopter in the treatment group.4
As for the technique being used to prevent myopia, the appropriate timeline for interventional treatment should be further investigated, the investigators said. Scleral CXL has not yet been done on human eyes in vivo, so potential problems should be investigated further, including long-term safety and stability of CXL, proper parameters such as exact position and suitable area of the eye to be treated, amount of energy needed and exposure time, they concluded.1
1. Zhang F, Lai L. Advanced research in scleral cross-linking to prevent from progressive myopia. Asia Pac J Ophthalmol. January 25, 2021. [Epub ahead of print].
2. Dotan A, Kremer I, Livnat T, et al. Scleral cross-linking using riboflavin and ultraviolet-a radiation for prevention of progressive myopia in a rabbit model. Exp Eye Res. 2014;127:190-5.
3. Zeugolis D, Liu S, Li S, et al. Scleral cross-linking using riboflavin UVA irradiation for the prevention of myopia progression in a guinea pig model: blocked axial extension and altered scleral microstructure. Plos One. 2016;11.
4. Li X, Wu M, Zhang L, et al. Riboflavin and ultraviolet A irradiation for 51. the prevention of progressive myopia in a guinea pig model. Exp Eye Res. 2017;165:1-6.