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.
ABSTRACT
AlM:To make a analysis of visual quality of iris location guided femtosecond laser assisted in situ keratomi ( LASlK) and iris location guided mechanical sub-bowman keratomileusis ( SBK) for high myopia treatment.METHODS:Femtosecond LASlK ( study group ) was performed in 102 eyes of 51 patients with high myopia and 70 eyes of 35 patients were received mechanical SBK ( control group ) from January to October 2013. The spherical refraction of all the patients was from -6. 00 ~-9. 50D. Best corrected visual acuity ( BCVA ) of the patients was ≥1. 0. Uncorrected visual acuity ( UCVA), BCVA, thickness of cornea flap, contrast sensitivity function ( CSF ) and senior ocular aberration were examined in these patients and follow-up was 1a.RESULTS: At 1a after surgery 94. 1% UCVA in study group reached ≥1. 0 and there was 94. 3% in control group. There was no significant difference between two groups (P>0. 05). Residual refraction of study group was-0. 08±0. 10 D and control group was -0. 10±0. 07 D. There was no significant difference of residual refraction between two groups (P>0. 05). C12 , C8 of senior ocular aberration and RMSH in study group was less than control group, amplification:0.1642±0.0519 and 0.2229±0.0382 (t=8. 077, P0. 05). C8 was 0. 0950±0. 069 and 0. 1858±0. 095 (t=7. 261, P0. 05). CONCLUSlON: Femtosecond LASlK and mechanical SBK is effective for high myopia. Compared to mechanical SBK, femtosecond LASlK shows more advantages in the senior ocular aberration and visual quality. The cornea flap is more regular from central to peripheral area with femtosecond laser.