| Objective: Through the retrospective comparative study of the myopiapatients underwent LASIK (laser in situ keratomileusis) after3to6yearsago with simple high corneal curvature and normal corneal curvature, Toevaluate the long-term security, effectiveness, predictability and stability ofLASIK performed on myopia with high-corneal curvature.Methods: To have a retrospective analysis of70cases (138eyes) ofLASIK surgery in the treatment center of the Second Hospital of HebeiMedical University from July2006to July2009.35cases (69eyes) of LASIKsurgery were selected as study group: the anterior surface corneal curvaturewere from47D to49D with OrbscanⅡbefore the operation; The preoperativeBCVA (best corrected visual acuity) were from0.8to1.2; the spherical degreewere from-1.50D to-11.00D, and26(37.7%) of them were high myopia; thecylinder degree were from-0.00D to-4.00D;the spherical equivalent werefrom-1.75D to-13.00D; the central corneal thickness were from479.0μm to597.0μm; the anterior corneal surface height were from0.00to0.04, and theposterior corneal surface height were from0.00to0.05. And the other35cases (69eyes) of LASIK surgery were selected as control group: the anteriorsurface corneal curvature were from40.9D to46.4D with OrbscanⅡbeforethe operative; The preoperative BCVA were from0.8to1.2; the sphericaldegree were from-2.25D to-9.50D, and26(37.7%) of them were high myopia;the cylinder degree were from-0.00D to-5.00D; the spherical equivalent werefrom-2.50D to-11.50D; the central corneal thickness were from483.0μm to602.0μm; the anterior corneal surface height were from0.00to0.03, and theposterior corneal surface height were from0.00to0.05. There were no otherindicators in addition to corneal curvature had statistically difference betweenthe two groups. UCVA (uncorrected visual acuity), refraction, corneal topography(central corneal thickness, corneal curvature,anterior cornealsurface height, and posterior corneal surface height) and postoperativecomplications were observed and compared3to6years after LASIK surgery,to evaluate the long-term safety, effectiveness, predictability and stability ofLASIK performed on myopia with high-corneal curvature. And theexamination of corneal curvature were executed by OrbscanⅡ system andPentacam system pre-and postoperation.Results: The postoperative UCVA of63eyes (91.3%) in the studygroup(35cases,69eyes) reached the preoperative BCVA, and thepostoperative UCVA were from0.8to1.2, the average number was0.95±0.15;The postoperative UCVA of66eyes (95.7%) in the control group(35cases,69eyes) reached the preoperative BCVA, and the postoperative UCVA were from0.8to1.2, the average number was0.98±0.14,and there were not significantdifference between these two groups(P＞0.05). The postoperative sphericalequivalent of the study group were from-1.00D to+0.75D, the averagenumber was-0.28±0.38D, and the control group were from-1.00D to+0.88D,the average number was-0.17±0.42D, there were not significant differencebetween these two groups(P＞0.05). The postoperative central cornealthickness of the study group were from440.0μm to546.0μm, the averagenumber was480.5±31.6μm, and the control group were from440.0μm to530.0μm, the average number was483.0±25.8μm, there were not significantdifference between these two groups(P＞0.05). The postoperative anteriorcorneal surface height of the study group were from2.00μm to6.00μm, theaverage number was3.13±0.97μm, and the control group were from1.00μmto6.00μm, the average number was3.06±1.12μm, there were not significantdifference between these two groups(P＞0.05). The postoperative posteriorcorneal surface height of the study group were from4.00μm to10.00μm, theaverage number was6.88±1.24μm, and the control group were from5.00μmto10.00μm, the average number was7.17±1.29μm, there were not significantdifference between these two groups(P＞0.05). The postoperative cornealcurvature value of the study group were from40.6D to45.8D, the average number was42.92±1.40D, and the control group were from40.0D to42.9D,the average number was41.32±0.83D, there were statistical significantdifference between these two groups(P＜0.05).The central corneal thicknessand corneal curvature value decreased after LASIK surgery in both these twogroups. The preoperative central corneal thickness of the study group werefrom479.0μm to597.0μm, the average number was544.6±23.1μm, and thepostoperative central corneal thickness were from440.0μm to546.0μm, theaverage number was480.5±31.6μm, there were statistical significantdifference between pre-and post LASIK surgery(P＜0.05). The preoperativecentral corneal thickness of the control group were from483.0μm to602.0μm,the average number was552.5±29.0μm, and the postoperative central cornealthickness were from440.0μm to530.0μm, the average number was483.0±25.8μm, there were statistical significant difference between pre-andpost LASIK surgery(P＜0.05). The preoperative corneal curvature value ofthe study group were from47.0D to49.0D, the average number was47.50±0.50D, and the postoperative corneal curvature value were from40.6Dto45.8D, the average number was42.92±1.40D, there were statisticalsignificant difference pre-and post LASIK surgery(P＜0.05). Thepreoperative corneal curvature value of the control group were from40.9D to46.4D, the average number was44.80±1.05D, and the postoperative cornealcurvature value were from40.0D to42.9D, the average number was41.32±0.83D, there were statistical significant difference between pre-andpost LASIK surgery(P＜0.05). The posterior corneal surface height were inthe normal range pre-and post LASIK surgery in both study and controlgroups, and there had no subclinical or clinical keratoconus occurred.Conclusions:1The differences of posterior corneal surface height between pre-andpost LASIK surgery of myopia patients with simple high corneal curvatureand normal corneal curvature had no significant difference. And there had nocorneal ectasia in both two groups, so the myopia patients with simple highcorneal curvature were security after LASIK. 2The difference of the percentage that the UCVA postoperative reachedthe BCVA preoperative between myopia patients with simple high cornealcurvature and normal corneal curvature had no significant difference,so themyopia patients with simple high corneal curvature had the same effectivenessand predictability.3The difference of the percentage that the UCVA postoperative reachedthe BCVA preoperative between the years from3years to6years after LASIKsurgery of myopia patients with simple high corneal curvature and normalcorneal curvature had no significant difference, so the myopia patients withsimple high corneal curvature and normal corneal curvature had good stabilityafter LASIK surgery. |
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