AIM: To evaluate the efficacy of formaldehyde release agents(FARs)on scleral cross-linking in living rabbits by measuring the changes in scleral biomechanical properties after the cross-linking.

METHODS: Totally 170 healthy New Zealand white rabbits were randomized into 17 groups, including 15 FARs groups(sodium hydroxymethylglycinate, diazolidinyl urea, imidazolidinyl urea, hydantoin and oxazolidine, each of them has three groups based on dosing concentration: 1/10 maximum allowable concentration group, 1/2 maximum allowable concentration group and maximum allowable concentration group), 1 glutaraldehyde(positive control)group and 1 blank control group. Subconjunctivally injected each FAR in the right eye. 60d after the injection, took the sclera at 1:00 and 7:00 sites of the right eye to make scleral strips. The scleral strip's thickness, elastic modulus, creep rate, ultimate stress and ultimate strain were measured to calculate the scleral biomechanical strength.

RESULTS: Sodium hydroxymethylglycinate, diazolidinyl urea, imidazolidinyl urea, hydantoin and oxazolidine increased the scleral biomechanical strength in a concentration-dependent manner. In these drugs, sodium hydroxymethylglycinate, diazolidinyl urea and oxazolidine had strong cross-linking effects, with obvious effects at the 1/10 maximum allowable concentration.

CONCLUSION: Sodium hydroxymethylglycinate, diazoimidazolidinyl urea, and oxazolidine have strong effects on sclera collagen cross-linking, can significantly improve the biomechanical strength of posterior sclera and have the potential to treat pathological myopia.