To investigate the effects of scleral crosslinking using genipin on ocular biological parameters and scleral biomechanics of form-deprivation myopia rabbits.

Sixty healthy New Zealand rabbits of 14 days old were collected.The right eyes were selected as experimental eye.The rabbits were randomly divided into three groups: control group with no treatment; myopia model group with eyelid suture procedure performed on the right eye; genipin injection group with eyelid suture procedure performed on the right eye combined with subconjunctival injection of genipin.The suture was removed 60 days after the eyelid suture procedure.The diopter, length of vitreous cavity, and axial length were measured.The sclera at 1: 00 and 7: 00 position of the experimental eye was used to make a scleral strip.The thickness, elastic modulus, creep rate, ultimate stress and ultimate strain of the sclera were measured.This study was approved by the animal experimental Ethics Committee of Bethune International Peace Hospital (2018-ky-09).

The diopters of genipin injection group, myopia model group and control group were (2.50±1.38), (0.33±0.52) and (2.08±0.52)D, respectively, the axial lengths of the three groups were (15.33±0.82), (15.83±0.41) and (15.00±0.43)mm, respectively; the changes in vitreous cavity lengths were (1.50±0.79), (2.59±0.83) and (1.48±0.66)mm, respectively; and the ratios of vitreous cavity length to axial length were 0.46±0.02, 0.51±0.02 and 0.47±0.02, respectively.The diopter in myopia model group was significantly lower than those in control group and genipin injection group, the axial length in myopia model group was significantly longer than that in control group, the change in vitreous cavity lengths and ratio of vitreous cavity length to axial length in myopia model group were significantly higher than those in control group and genipin injection group, the axial length in myopia model group was significantly longer than that in control group, the differences were statistically significant (all at P<0.05). The elasticity modulus was (9.10±3.12)MPa and ultimate stress was (1.42±0.57)MPa in genipin injection group, which were significantly higher than (6.98±3.30)MPa and (1.15±0.57)MPa in control group, and (6.25±3.17)MPa and (0.82±0.38)MPa in myopia model group (all at P<0.05). The ultimate strain was (20.99±5.60)% in genipin injection group, which was significantly lower than (25.08±6.35)% in control group and (27.78±8.20)% in myopia model group, with significant differences between them (both at P<0.05).

Posterior sub-Tenon capsule injection of genipin for collagen crosslinking in the sclera increases the biomechanical strength of sclera and effectively prevents the development of form-deprivation myopia in rabbits, which provides a new idea for the prevention and treatment of myopia in the future.

Myopia, degeneration; Genipin; Form deprivation; Sclera crosslinking; Animal model