Objective     To observe the degradation of chitosan film under rabbit scleral flap

eye irritation

and intraocular pressure and estimate biocompatibility of chitosan film and the effect of lessening intraocular pressure.      Methods     Chitosan film was extracted from shell of snow-crab. Sixteen rabbits (32 eyes) were divided randomly into 2 groups with 16 eyes in each group. Group A was treated with trabeculectomy as control and Group B treated with trabeculectomy and implantation of chitosan film under scleral flap. The intraocular pressure

inflammatory reaction

pathological change after operation were observed.      Results     There were no significant alterations regarding the cornea and iris. Inflammatory reaction was seen on day 7 after operation. Partial chitosan film degradation appeared and inflammatory reaction remitted on day 14 after operation. The chitosan film was degraded into fragment and the inflammatory reaction almost disappeared on day 56 after operation. There existed tissue space and follicles around the implanted materials in Group B; in Group A

however

instead of tissue space and follicles

histological structure disarrangement and cicatrisation were noticed. The intraocular tension varied significantly between the two groups at 8th week postoperatively (P0.01).      Conclusion     Chitosan film has good histocompatibility and inhibitory effect on fibroplasia. It can effectively decline intraocular pressure.