Effect and safety of applying mitomycin C in laser - assisted subepithelial keratomileusis for extreme high myopia / 国际眼科杂志(Guoji Yanke Zazhi)

ABSTRACT

AIM: To observe the effect and safety of applying mitomycin C ( MMC ) in laser - assisted subepithelial keratomileusis ( LASEK) for extreme high myopia. ●METHODS:LASEK with 0. 02% MMC was performed in 364 eyes of 182 patients with extreme high myopia and spherical equivalent was-9. 0 to-10. 25 D. All the patients were divided into four groups according to the applying time of MMC. The time in Group l was 10s, in GroupⅡwas 25s, in Group Ⅲ was 40s and 55s in Group lV. Uncorrected visual acuity ( UCVA ) , residual refraction, Haze, healing time of corneal epithelium, density and variant index of corneal endothelium was examined in these patients and follow-up 6mo. ●RESULTS:At 6mo after surgery, 76. 3%, 94. 0%, 92. 3%and 93. 8% of the patients in Group l, GroupⅡ, GroupⅢ and Group lV respectively achieved the UCVA better than 15/20. There was significant difference of UCVA between Group l and the other three groups (χ2=19. 610, P=0. 000). Proportion of the residual refraction between ± 0. 5D in Group l (78. 8%) was lower than other groups (95. 2% in Group Ⅱ, 93. 3% in Group Ⅲ, and 92. 7% in GroupⅣ) at 6mo and there was significant difference (χ2=16. 329, P=0. 001). Group l had more Haze statistically than the other three groups at 6mo postoperatively ( Hc=50. 110, P=0. 000). The healing time of cornea epithelium seem to be no statistically difference between each group at 6mo (χ2=11. 611, P>0. 05). MMC had no influence on the density of corneal endothelium in each group postoperatively (P>0. 05), there were 3071. 3±284. 4 cells/mm2 in Group l, 3 105. 6 ± 337. 8 cells/mm2 in Group Ⅱ, 2 986. 3 ± 304. 1cells/mm2 in Group Ⅲ and 3 088. 7 ± 372. 5 cells/mm2 in Group lV respectively. The variant index of corneal endothelium calculated in each group at 6mo after surgery was 24. 72 ± 6. 52, 22. 93 ± 6. 74, 24. 38 ± 6. 63 and 23. 14±7. 22 repectively, compare with that preoperatively there were no statistically differences (P>0. 05). ●CONCLUSION: For extreme high myopia LASEK with 0. 02% MMC is effective and safe. The MMC applying time of 25s in LASEK can effectively reduce Haze after surgery and decrease potential complications.