Clinical Evaluation On The Cornea Flap In Different Thickness

Objective:To investigate morphologically the different changes of cornea tissue between thick and thin cornea flap with confocal microscope. Meanwhile to compare visual function between thick and thin cornea flap after LASIK.Methods:50 cases (100 eyes) who had received LASIK were divided into the thin cornea flap group (48eyes,group A)and the thick cornea flap group (52 eyes,groupB).The age was 23±4.5 years old,Spherical equivalent diaopter (SE) were -4.76±2.3DS and -3.03±2.2DS.Inspection items included visual acuity (VA),refraction,wave-front analysis,contrast sensitivity during pre-and post-lasik,at the same time,all eyes were examined by confocal microcopy.Using Moria 90um and 130um keratome with Allegretto Excimer laser machine.Results:①Refraction: There was no difference between the two groups. Post- lasik3-6months: groupA0.35±0.21DS; groupB0.45±0.69DS (p>0.05).②The comparison results of confocal microscope:The thickness of cornea flap:groupA107.37±20.5um;groupB149±25.2um(p<0.05).The thickness of wrinkle:groupA63.71±15.8um;groupB48.16±20.7um(p<0.05). The thickness of acellular area:groupA69.93±15.8um;groupB55.63±23.7um(p<0.05). The thickness of activation cornea cells: groupA60.15±30.9um; groupB 51.86±27.9um(p<0.05). The density of anterior stromal:groupA 825.14±156.9μ㎡ ; groupB853.54±126.8μ㎡(p<0.05). There were significant differences on the thickness of cornea flap,the thickness of wrinkle,the thickness of acellular area ,the thickness of activation cornea cells,density of the anterioer stromal, but there was no difference on posterior stromal (groupA 619.78±147μ㎡ ,groupB600.3±139.5μ㎡ ,p>0.05).③Wave-front analysis: There was no difference between two groups in Z3-3,Z3-1,Z31,Z33,Z40, RMS3, RMS4,RMS5,RMS6,RMSh(p>0.05)pre-and,post-operation.④Contrast sensitivity: There was also no difference between two groups (p>0.05) pre-and post-operation.Post-lasik one month:WOG: 72.9518(groupA); 68.9412(groupB)(p>0.05).WG:125.51(groupA); 107.2567 (groupB)(p>0.05). REDTEST:125.1234(groupA);107.2567(groupB)(p>0.05).READAPTION: 3.7667 (groupA); 4.2417 (groupB) (p>0.05). Post-lasik3-6month: WOG: 80.6573 (groupA);69.8356(groupB)(p>0.05).WG:98.6176(groupA);96.2511 (groupB)(p>0.05).REDTEST:150.6731(groupA);148.369(groupB)(p>0.05).READAPTION:4.1667(groupA);5.1258(groupB)(p>0.05).Conclusions:From the point of confocal microscope view,morphologic changes of cornea was significant with different thick flap.It is not cicatrical healing between the cornea flap and stromal.The injury of cornea tissue in the thin cornea flap was server than that of in the thick cornea flap even though there was no significant difference between thin and thick cornea flap group in clinical refraction correction,wavefront and contrast sensitivity.