Effects of scleral cross-linking using genipin on the process of form-deprivation myopia in the guinea pig: a randomized controlled experimental study

Abstract

BackgroundScleral cross-linking (CXL) is a novel attempt to slow down the axial elongation process in animal eyes. As a natural CXL reagent, genipin would be also effective for the prevention of myopia process. Thus, the present study was designed to evaluate the effects of scleral cross-linking using genipin on the form-deprivation (FD) myopia process of guinea pigs.MethodsTwenty-seven 3-week-old pigmented guinea pigs were randomly divided into three groups. Group A (n = 8) is the untreated control group. Group B (n = 8) is the FD control group, where all eyes were induced with monocular FD for 21 days. In Group C (n = 11), a sub-Tenon injection of 0.10 mL 0.50 % genipin was performed on FD eyes at day 0, 7 and 14 during the 21-day monocular FD. The ocular refraction, axial length, biomechanical test and light and electron microscopy were measured on all eyes to check the efficacy and safety of this scleral CXL technique.ResultsCompared with Group A, significant increases in myopic refractive errors, axial elongation and reductions of scleral fibril diameter and density were observed in the 21-day FD eyes of Group B (P < 0.05). In Group C, the scleral CXL resulted in less myopia and axial elongation as compared with Group B (P < 0.05); a significant thickening of scleral fibrils was found after sub-Tenon injections of genipin; no histological damage on the retina or choroid was observed in Group C at the end of this study.ConclusionsThe FD myopia in guinea pig eyes was effectively blocked by the scleral CXL using sub-Tenon injections of genipin. No histological damage was found on the retina or choroid of these treated eyes. Further studies are needed to examine the long-term efficacy and safety of this CXL technique.Electronic supplementary materialThe online version of this article (doi:10.1186/s12886-015-0086-z) contains supplementary material, which is available to authorized users.

Evaluation of Therapeutic Tissue Crosslinking (TXL) for Myopia Using Second Harmonic Generation Signal Microscopy in Rabbit Sclera

“…7–9 Wollensak 10 has described previously the use of a sT injection using glyceraldehyde (a chemical crosslinking agent similar in concept to the FARs described in this study) to stiffen the rabbit sclera 10 and genipin has been shown to limit axial length in FD guinea pigs. 11,12 These investigators have demonstrated an advantage of using a soluble chemical agent over the photochemical (CXL) technique. Making an injection into sT space is much simpler than carrying out the photochemical procedure, which requires a surgical procedure to access the posterior sclera with a UV light source.…”

Experimental myopia increases and scleral crosslinking using genipin inhibits cyclic softening in the tree shrew sclera

“…Our results support this idea as SXL using genipin strengthened the myopic scleras by inhibiting inelastic deformations due to cyclic loading. Wang and Corpuz have successfully used subconjunctival injection of 0.5% (22.1 m m ) genipin to slow form‐deprivation myopia in guinea pigs. We have used a much lower concentration of 0.25 m m in this study suggesting that a low but sustained delivery (24 h in this study) of genipin to the sclera may lead to significant biomechanical strengthening.…”

“…It is a naturally occurring organic compound derived from the fruit of the gardenia plant ( Gardenia jasminoides ) . Genipin has been shown to alter the scleral material properties of porcine sclera and to slow myopia progression in guinea pigs . Campbell et al .…”

Prevention and Management of Myopia and Myopic Pathology

“…119,120 UV-A use with scleral CXL has been associated with decreased dark-adapted ERG amplitudes up to 3 months posttreatment, with apoptotic cells and ultrastructural changes in retina layers also found. 121 111,118,119,[122][123][124][125][126][127][128][129][130] Glyceraldehyde is a non-light-activated chemical shown to increase scleral rigidity, but has ill effects on the neighboring cornea and muscles. 120 Alternatively, topical beta-nitroalcohols (or ''BNAs,'' commonly found in antibiotics and shampoos) and formaldehyde releasers (or ''FARs,'' which are preservatives found in cosmetics, body wash, and ophthalmic solutions; e.g., BLU Gel A multidose artificial tears, SOOFT italia [Montegiorgio FM, Italy]) effectively crosslink corneal and scleral collagen in vitro, and have very good safety profiles (Hoang Q, et al IOVS 2013;54:ARVO E-Abstract 136).…”