Research On The Vision Function And Operation Indication Of The Cataract At Early-middle Stage

BackgroundCataract is the first leading cause of blindness in the world and it’s visionrehabilitation rate is the highest. The operation indication for cataract always depend onvisual acuity(VA). The cataract patients were waited until mature stage,when the VAdecreased to hand move or even light perception. Cataract surgery indication graduallychanged as the continuous improvement on surgical techniques and equipment.VA0.3or0.4may be surgery indication according to ophthalmology textbook，as in most hospitals.The early cataract patients (VA≥0.5) with visual function impairment may receivesurgical treatment if they request. In fact，many patients can’t dicide whether receiveoperation or not. They ask doctors to give a guidance, but the doctor can’t make a clearjudgment according to the current cataract surgery indication.Visual function include visual acuity, visual field,color vision, dark adaption,stereoscopic vision and contrast sensitivity. VA is only one aspect of visual function, whichreflects the ability to distinguish small target under the condition of the highest contrast.Ourliving environment is composed by a large number of different shapes, sizes, colors andcontrast objects. Visual function impairment caused by cataract include visual acuity, visualfield, contrast sensitivity and so on.It is not enough that VA be the only evaluation criterionfor the visual impairment and cataract surgery indication. More suitable methods should befound to reflect integrated visual function impairment in cataract patients. Suitableoperation indication should be found out for the early cataract patients with good VAcombined with visual function impairment.ObjectiveWe aim to elvaluate the visual impairment in the early and middle cataract patientsthrough analysis the Visual Function(VF) and Quality of Life(QOL) questionnaires,contrast sensitivity(CS), glare sensitivity(GS) and visual field, to find suitable operation indication of early cataract (VA≥0.5).MethodsThe clinical data of the early and middle cataract inpatients and outpatients werecollected in our hospital. The VF and QOL questionnaire, CS, GS and visual fieldexaminations were administered and their variabilities between the patients were analyzed.We analyzed the correlation between presenting visual acuity and the score of VF and QOLquestionnaire，best corrected visual acuity and CS、GS，best corrected visual acuity andmean deviation (MD) of visual field. According to the cataract surgery indication ofophthalmology textbook, patients VA0.3or0.4may be operated. So95%scores of the VFand QOL questionnaires,CS, GS and MD of cataract patients withVA0.3or0.4establishedused the statistical method of reference range estimation may be as the operation referenceof ertly cataract(VA≥0.5).We established95%scores of the VF、QOL questionnaires andin cataract patients with presenting visual acuity≥0.3and＜0.5,95%scores of CS,GSand MD in cataract patients with best corrected visual acuity≥0.3and＜0.5. To verifyand screen out the more suitable operation indication, the operation rate between actuallyrequired surgery cases and might be operated according to the operation reference werecompared in early cataract patients.Results1Results of VF、QOL questionnaires research.(1) There were significantly positive correlations between presenting visual acuityand the scores of VF、QOL questionnaires(P＜0.01). VF、QOL questionnaires and VA maybe used to evaluate the visual impairment caused by cataract together with visual acuitytest.(2) The scores of VF and QOL questionnaires of the of presenting VA≥0.5andrequired operation group were significantly lower than not required operation group,whilethere was no statistical difference compared with the presenting VA0.3～0.4group. Thepresenting VA≥0.5and not required operation group was significantly higher than thepresenting VA0.3～0.4group. These results suggest that VF、QOL questionnaires candistinguish the differences between wether required operation or not wich VA test couldnot.They may be used as the operation reference of early cataract.(3) The95%scores of VF questionnaire of the presenting VA0.3～0.4group was 73.3, the QOL questionnaire was94.4.As VF questionnaire sore＜73.3was surgicalreference，the operation rate between actually required surgery cases and may be operatedin early cataract patients had no statistical difference.The missed and mistaken operationrates were low. As QOL questionnaire sore＜94.4was surgical reference，the operation ratewas higher than actual surgery rate. Although the missed operation rate was lower, butmistaken surgery rate was63.16%. Therefore, VF questionnaire was more suitable assurgical reference compared with QOL questionnaire.2Results of CS、GS research.(1) All frequencies GS of all the cataract patients were significantly lower than CS.At all frequencis CS and1.5，3，6，12cpd GS were significantly positive correlations withbest corrected visual acuity. They may be used to evaluate the visual impairment caused bycataract together with visual acuity test.(2) At all frequencies of CS and1.5，3，6，12cpd GS，the group of best correctedVA≥0.5and required operation patients were significantly lower than not requiredoperation group.These results suggest that CS and1.5，3，6，12cpd GS can distinguish thedifference between the early cataract patients wether required operation or not which VAtest could not. They may be used as the operation reference of early cataract.(3) The95%CS of the best corrected VA0.3～0.4group at1.5cpd、3cpd、6cpd、12、18cpd were25、20、16、0、0, GS were13、15、4.2、0、0. At all frequencies of CS andGS,the actual operation rate and maght be operated in early cataract patients were compered.The missed and mistaken operation rate were compered too.The CS6cpd＜16，GS3cpd＜15were more suitable as surgical reference than the other frequencies.3Results of visual field research.(1) There was significantly negatively correlation between best corrected visual acuityand MD. MD may be used to evaluate the visual impairment caused by cataract.(2) MD of the best corrected VA≥0.5and required operation group were significantlyhigher than not required operation group, while there was no statistical differencecompared with the best corrected VA0.3～0.4group. The best corrected VA≥0.5and notrequired operation group was significantly lower than the best corrected VA0.3～0.4group.These results suggest that MD can distinguish the differences between the earlycataract patients wether required operation or not witch VA test could not. (3) The95%MD of the best corrected VA0.3～0.4group was2.74dB.As MD wassurgical reference，the operation rate was higher than actual surgery rate. Although themissed operation rate was0%, but mistaken surgery rate was87.1%.It suggested that MDlower than2.74dB be as the operation reference of early cataract was not suitable.Conclusion1There were significantly correlations between the scores of VF、QOL questionnairesand presenting visual acuity. There were significantly positive correlations between allfrequencis CS and1.5，3，6，12cpd GS and best corrected visual acuity. There wassignificantly negatively correlation between best corrected visual acuity and MD. They maybe used to evaluate the visual impairment caused by cataract together with visual acuitytest.2We recommend that the VF questionnaire score <73.3, CS6cpd <16, GS3cpd <15be as the surgery reference indications in early cataract patients who puzzled by operatingor not.