An Experimental Trial Of Photorefractive Keratectomy Of Rabbits With Amniotic Membrane Extraction

Purpose: To establish the model of photorefractive keratectomy(PRK) in rabbits,and to investigate self-made amniotic membrane extraction's effect of corneal fog opacity (haze) after PRK.Methods: We prepared the healthy human amniotic membrane (AM) according to the routine reference, reserve epithelial cell,freeze thawing repeatedly and filter to obtain amniotic membrane extraction,stored at the room temperature.54 eyes of 27 New Zealand white rabbits were operated by PRK in the same condition.All of the rabbits were divided into three groups at random:amniotic membrane extraction group (experimental group),excitatory autacoid group ( control group ) and diluents bases group (blank group).There are 18 eyes of 9 rabbits in each group.Antibiotic eye drops were given for each group's rabbits after PRK . Amniotic membrane extraction were given for experimental group's rabbits , 0.1% dexamethasone phosphate eye drops were given for control group's rabbits and diluents bases without amniotic membrane extraction were given for blank group's rabbits 48 hours later . Postoperative clinical examine everyday,measure,note and analyzed the haze information as the Fantes'standard in 1,2,4,8 weeks.3 rabbits were selected randomly from each group for the pathologic examination,one rabbit was killed from them in each group in 1,4,8 weeks after operation and extirpated the eyeball for pathologic observation,observe the information of the cornea,inflammatory cells and desmocyte.Results: In the earlier period after PRK,all the results of the cornea fluorescein staining of the three groups were positive,but most of the corneal epithelium defection were repaired at 4~6 days after PRK and experimental group is faster than the other groups. The incidence of haze was 100% after PRK,all the eyes started to appear the haze in 1 week after opertion,especially from 3~4 weeks to 8 weeks were severe.The degree of haze in experimental group and control group were obviously less than the degree of haze in blank group after operation.(P<0.05)Conclusion: Amniotic membrane homogenate has the role of promoting corneal epithelium recover,and could reduce the degree of haze after PRK in rabbits.