Early cornea healing response of PRK and free-flap Epi-LASIK under different cutting depth in rabbit / 中华实验眼科杂志

ABSTRACT

Background Free-flap Epi-LASIK surgery show a fast epithelial healing and mild trauma responses.Its mechanism is notable. Objective The aim of this study was to compare the corneal epithelial healing response following photorefractive keratectomy(PRK)and flap-free Epi-LASIK surgery. Methods Twelve experimental rabbits were randomly assigned to high cutting group(-10.00 D)and low cutting group(-3.00 D),and 2 normal matched rabbits were used as controls.PRK was performed in lateral eyes and flap-free epipolis laser in situkeratomileusis(Epi-LASIK)surgery was curried out in the fellow eyes.The corneal wound healing response in early stage of post-operation was examined under the slim lamp,and the inflammatory cells infiltration in cornea,basic fibroblast growth factor(bFGF)and nuclear transcription factor(NF-KB)expressions in corneal stroma were detected by hematine-eosin staining and immunohistochemstry in the seventh day after operation. Results The inflammatory reaction was milder in the eyes with Epi-LASIK than ones of PRK under the slim lamp.No significant difierences were found in numbers of inflammatory cells in cornea.expressions of bFGF and NF-κB in corneal stroma between two types of surgeries in low cutting group(P＞0.05).In high cutting group,the numbers of inflammatory cells were(12.25±1.22)/400 field in PRK eyes,and those of free-flap Epi-LASIK eyes were(6.67±0.31)/400 field,showing obvious difference between them(t=-8.87,P＜0.01).Expressions of NF-κB(A value)in cornea were 6.11±1.36 and 41.82±8.7 1 in PRK eyes of low cutting group and high cutting group.and those in free-flap Epi-LASIK were 3.01±0.81 and 11.59±4.55.indicating a drastically increase in PRK eyes(P＜0.05).The expressions of bFGF(A value)in corneal stroma were 33.59±6.98 and 123.68±18.81 in PRK eyes and those in free-flap Epi-LASIK eyes were 69.20±8.85 and 123.68±1 8.81 in low cutting group and high cutting group,presenting a considerably decrease in PRK eyes (P＜0.05).The corneal epithelial healing was faster in free-flap Epi-LASIK eyes than that in PRK eyes.and deeper cutting slowed the healing procedure. Conclusion In low cutting group,healing time of corneal epithelium is close between PRK and flap-free Epi-LASIK.But in high cutting group,epithelial healing is faster and inflammatory reaction is lighter in flap-free Epi-LASIK compared with PRK.