Contrastive Study On The Effect Of Different Methods To Correct Preexisting Corneal Astigmatism During Phacoemulsification

In recent years, with the development of ophthalmologic micrurgy and the improvement in micro instrument, the cure methods of cataract is gradually turning from recovering vision operation to refractive operation. The cornea astigmatism of preoperation not only influence the vision of postoperation.but also influence the application of varied functional intraocular lens.The toric IOL has its own advantage but it’s expensive cost limited its use.So to explore the cost-effective methods of correcting the preexisting cornea astigmatism become the ophthalmologist’s research focus.Our research team has proved the couple" T"incisions ability to improve the patience’s UCVA and reduce the cornea astigmatism.This research expanded the sample number and stricted the included criterion.We decomposed cornea astigmatism into vector J45and P,and then explore the rules of different methods to correct cornea astigmatism. We choosed Visual acuity、Visual contrast sensitivity(CS)、Wavefront aberration(WF)、vision function (VF) and quality of life (QOL)questionnaire as research tools to study the effect of different methods on quality of vision and life.Objective:According to the outcome of corneal topography, we select different methods to correct preexisting corneal astigmatism during phaco. We choose Visual acuity, cornea astigmatism vector (Jo，J45，P)， Visual contrast sensitivity(CS), Wavefront aberration(WF), vision function (VF) and quality of life (QOL)questionnaire as research tools to study the effect of different methods on quality of vision and life, to reveal the ordinary principles and provide clinical accurate data.We wish that it will establish a rationale of choosing the best operation incision site in clinical cataract cure.Methods:From August 2011 to August 2012,120 age-related cataract patients(125eyes)for surgery in our hospital were divided into 3 groups according to the preexisting corneal astigmatism, different incisions for cataract surgery were made for each group. Group A(35 eyes), the preexisting corneal astigmatism less than 1.0D, received superior(11:00) clear corneal incision(CCI);GroupB(50 eyes), the preexisting corneal astigmatism was between 1.0D to 2.0D, which were divided into 2 groups.Group Bt(25 eyes), CCI was made on the steepest meridian, the helping incisions and the major incisions had a included angle about 120 degree. Group B2(25 eyes), CCI was the same as Group A; Group C(40 eyes):the preexisting corneal astigmatism more than 2.0D,which were divided into 2 groups, Group CL(20 eyes), besides the superior(11:00) CCI, for surgery on the steepest meridian, an additional couple of "T" incisions were made to release the preexisting corneal astigmatism, Group C2(20 eyes), CCI was the same as Group A. The operation eyes were all implanted Rayner foldable posterior chamber intraocular lens. The UCVA, corneal astigmatism were observed at 1 week,1 month and 3 months after operation, The Visual contrast sensitivity(CS)、Wavefront aberration、vision function (VF) and quality of life (QOL)questionnaire were observed at 3 months after operation on B、Cgroups. comparing all the data based on statistical analysis.Results:1.The UCVA of postoperation in each groupThe UCVA in each group after surgery was all better than that of preoperation, difference being statistically significant (P＜0.01). At 1 week,1 month and 3 months, the difference between Group B1 and Group B2 was significant (P＜0.05), the UCVA of Group B1 excel that of Group B2. At 1 week,1 month and 3 months,the difference between Group C1 and Group C2 was significant (P＜0.05), the UCVA of Group C1 excel that of Group C2.2. Cornea astigmatism vector (Jo，J45，P) after operationThe cornea astigmatism was dicomposed into Jo，J45 and P with a vector-based method,and statistically analyzed. In Group A, there were no significant difference on the corneal astigmatism before and after operation (P>0.05). The corneal J0 and P in group B1 after surgery were lower than that of preopertion, difference being statistically significant (P<0.05,P<0.01,P<0.01), between Group B1 and Group B2, there have difference being statistically significant at lweek,1 month and 3 months (all P＜0.01), Group B1 J0 and P was lower than Group B2.The corneal J0 and P in Group C1 after surgery were lower than that of preopertion, difference being statistically significant (P<0.01), at 1 week,l month and 3 months, difference being statistically significant between Group C1 and Group C2 (all P<0.01), Group C1 J0 and P was lower than Group C2.3. CS in B、C groups 3mons after operationUnder four lighting conditions(photopia,photopia with glare,scotopia and scotopia with glare)and five spatial frequencies(1.5,3,6,12,18cycles per degree) the CS scores of group B1 was higher than groupB2,group C1was higher than group C2.The difference was significant(all P<0.01).under the condition of photopia with glare the CS scores was higher than the condition of photopia in group B1、B2、C1、C2.But the increased values in group B1 and C1 was higher than group B2 and C2respectively(P<0.05). under the condition of scotopia with glare the CS scores was lower than the condition of scotopia in group B1、 B2、C1、C2. But the decreased values in group B1 and C1 was lower than group B2 and C2 respectively(P<0.05).4. WF in B、C groups 3mons after operationWavefront aberration test results indicated that the mean values of coma aberration,RMS3,RMS5,RMS6,RMSh,RMSg (root mean square of general aberration) of group B1 were obviously lower than that of group B2 (all P＜0.05).No statistically significant was found between group B1 and groupB2of RMS4and spherical aberration (P>0.05).The Strehl ratio(SR) of group B1 was 0.026±0.017and group B2 was 0.010±0.004. difference being statistically significant (P＜0.01).Wavefront aberration test results also indicated that values of coma aberration,RMS3,RMS5,RMS6,RMSh,RMSg of group C1 were obviously lower than that of group C2(all P<0.01).No statistically significant was found between group C1 and groupC2of RMS4and spherical aberration(P>0.05). The Strehl ratio(SR) of group C1 was 0.019± 0.014.and group C2 was 0.006 ± 0.002. difference being statistically significant (P＜0.01).5.VF and QOLquestionnaire scores of B、C groups in preopration and 3mons after operationThe VF scores improved significantly in the four groups(B1、B2、C1、 C2)after the cataract surgery(all P＜0.01).Before surgery the difference of VF scores between group B1 and group B2 was not significant(all P>0.05).After surgery the difference of the vision adaption scores,stereo vision scores and totalVFscores between group B1 and group B2 were significant(all P<0.05), groupB1 was higher than groupB2. No statistically significant was found between group B1 and groupB2 of subjective vision scores and peripheral visual field scores(P>0.05). Before surgery the difference of VF scores between group C1 and group C2 was not significant(P>0.05). After surgery the difference of the vision adaption scores,stereo vision scores, peripheral visual field scores and totalVFscores between group B1 and group B2 were significant(all P＜0.05). groupC1 was higher than groupC2. No statistically significant was found between group C1 and groupC2 of subjective vision scores (P>0.05).The QOL scores improved significantly in the four groups(B1、B2、C1、 C2)after the cataract surgery(all P＜0.01). Before surgery the difference of QOL scores between group B1 and group B2 was not significant(all P>0.05). After surgery the difference of condition of psychology scores and total QOL scores between group B1 and group B2 were significant(P<0.05). GroupB1 was higher than groupB2. No statistically significant was found between groupB1 and groupB2 of ability of life scores,ability of action scores and ability of social scores (P>0.05). Before surgery the difference of QOL scores between groupC1 and group C2 was not significant(P>0.05). After surgery the difference of ability of action scores, ability of social scores, condition of psychology scores and total QOL scores were significant(all P＜0.05). Group C1 was higher than groupC2. No statistically significant was found between group C1 and groupC2 of ability of life scores(P>0.05).Conclusion:1. The corneal astigmatism did not change after 3.0 mm CCI phaco.The incisions on the steepest meridian can reduce corneal astigmatism when the preexisting corneal astigmatism was between 1.0D to 2.0D. The couple of "T" incisions on the steepest corneal meridian can correct the corneal astigmatism when the preexisting corneal astigmatism was more than 2.0D.2. The incisions on the steepest meridian and the couple of "T" incisions on the steepest corneal meridian can increase CS scores and decrease the influence of glare on IOL eyes.3. The incisions on the steepest meridian and the couple of "T" incisions on the steepest corneal meridian can improve the patience’s quality of optical.4. The incisions on the steepest meridian and the couple of "T" incisions on the steepest corneal meridian can improve the patient’s quality of life.