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AIM:To contrast analysis of postoperative variation of corneal posterior surface heights after Femtosecond LASlK ( FS - LASlK ) and small incision lenticule extraction ( SMlLE) for high myopia. ●METHODS: Sixty-seven cases of high myopic patients (132 eyes) operated with laser corneal refractive in our hospital from May to Dec. in 2015 (-6. 00D≤spherical equivalent degree≤-10. 00D) were selected and divided into FS-LASlK group and SMlLE group. The thickness of corneal flaps at FS-LASlK and the thickness of map at SMlLE were designed to be 110μm. Corneal posterior surface heights were examined by Pentacam at preoperation, postoperative 3 and 6mo after FS-LASlK and SMlLE operation. Surface height changes after preoperative, postoperative 3 and 6mo were compared by measuring Pentacam corneal analysis system. ●RESULTS: Six months after operation, the FS-LASlK posterior corneal surface height was 6. 47 ± 1. 65mm, significantly higher than 5. 20 ± 1. 32mm before operation. SMlLE posterior corneal surface height was 6. 40 ± 1. 33mm, significantly higher than 5. 18 ± 1. 25mm before operation, the differences were statistically significant( P0. 05). ●CONCLUSION:After FS-LASlK and SMlLE, the corneal posterior surface is protrusive. FS - LASlK is slightly obvious than SMlLE in early period. The stability of the posterior surface is better after SMlLE.
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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.
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To evaluate the visual performance of the patients with traumatic corneal astigmatism, after the treatment of topography guided off-flap epipolis laser in situ keratomileusi (off-flap Epi-LASlK). ●METHODS: This prospective clinical study was comprised of 21 eyes of 21 patients with irregular corneal astigmatism caused by trauma, they were treated by off-flap Epi - LASlK from July 2012 to December 2013. The data included uncorrected visual acuity ( UCVA), best spectacle - corrected visual acuity ( BSCVA ), contrast sensitivity 1, 6mo before and after surgery; the healing area percentage of corneal epithelia, the healing time of corneal epithelia and pain score at 3d after surgery. ●RESULTS: Postoperative 1mo both UCVA and BSCVA were improved significantly than that before surgery (t =15. 703, 4. 351, P0. 05 ). Postoperative 6mo except the 3c/ d spatial frequency, the remaining 3 spatial frequency contrast sensitivity compared with those before operation were significantly improved ( P ●CONCLUSlON: Topography-guided off-flap Epi-LASlK is safe and effective in treating the patients with traumatic corneal irregular astigmatism. The operation can improve both the contrast sensitivity and the visual performance.
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AlM: To compare the different formulas in intraocular lens(lOL) power calculations on high myopia after LASlK with cataract patients who received the phacoemulsification and intraocular lens implantation ( Phaco+lOL) . METHODS:This was a retrospective study. Data from 102 eyes of 61 cataract patients with high myopia, who received Phaco+lOL after LASlK, were collected. Patients were divided into three groups by formulas in lOL power calculations before surgery: Holladay group ( 11 cases, 21 eyes), Haigis-L group (30 cases, 47 eyes) and SRK-T group (20 cases, 34 eyes). The ratios of equivalent lOL power after LASlK were predicted and the accuracy of their predictions were compared 3mo after surgery. lt was an index of reliability of the formulas outcomes. RESULTS:The ratios of equivalent lOL power after LASlK using the Holladay, Haigis-L and SRK-T formulas were 0. 86 ± 0. 41D, 0. 43 ± 0. 30D and 1. 27 ± 0. 58D, respectively . There was no significant difference between Holladay group and SRK-T group ( t=-0. 271, P=0. 625>0. 05 ). However, significant difference was found between Haigis-L group and Holladay group ( t=2. 249, P=0.047 CONCLUSlON:The Haigis-L formula is more accurate than the SRK-T and Holladay formulas in predicting lOL power for cataract patients with high myopia after LASlK.