Study Of The Correlation Between Intraocular Len Design And Poster Capsule Opacification

Background:Cataract is one of the common eye disease, the problem is remarkable by the aging of population.Now surgey is the only therapy. Phacoemulsification associating with intra ocular lens insertion has many good qualities, such as short incision, rapid recovery, stable refraction. However, it also has some unconquerable complications. Poster capsule opacification (PCO) and poster capsule wrinkle are common phenomenon ,and PCO is the important factor of affecting the patients'eyesight.The ratio of PCO is nearly 10%～50% after surgey in three years. Nd:YAG laser therapy is the common clinical way, thus the Nd:YAG laser equipment is expensive and hardly develop in grassroots and it can also induce some complications, such as IOL injurement, Cystoid Macular edema,etc.The correlated factors of PCO include time of surgey,age,the residual len epithelial cells,the state of CCC,and the character of IOL also can affect the formation of poster capsule opacification and poster capsule wrinkle.So it is high clinical application value on research of how to insert excellent IOL for reducing the ratio of PCO formation.Objective:This study is to compare the difference in posterior capsule opacification and posterior wrinkle after phacoemulsification when foldable intraocular lens with two different shapes are implanted,at the same time from the relation of poster capsule opacification and poster capsule wrinkle, we gain mechanical parameters from experiment,using Finite Element Method(FEM) for analyzing the stability of the two different shaped IOL;We expect the research can give the academic and clinical basis for IOL design.Methods1. The clinical data and following-up results are from 89patient (109 eyes) , which were treated in the department of Ophthalmology , Daping Hospital ,The Third Military Medical University from September 2006 to May 2008 at the avoided standard of diabetes , glaucoma, high myopia,aged related macular degeneration and other seriously affected eye general dieases ,and which were analyzed .There are 55 eyes (A group) which implanted the LI61SE foldable intraocular lens of Baush&Lomb .There are 54 eyes (B group ) which implanted the Akreos Adapt foldable intraocular lens of Baush&Lomb , we register the eyesight and investigate the central and peripheral poster capsul opacification and the central and peripheral poster capsule wrinkle after nearly five months.2. Using IOL compressibility equipment measure the tensile force of LI61SE foldable intraocular lens and Akreos Adapt foldable intraocular lens at different compressing diameter(LI61SE foldable intraocular lens ,12.5mm—9mm,the spacing distance is 0.5mm)(Akreos Adapt foldable intraocular lens ,11,10.7,10.5mm-9mm,the spacing distance is 0.1mm), measure it three times,the precision of IOL compressibility equipment is±0.1mN.3. Following the characters of the different IOLs,and using the compressive force that have measued, combining with the parematers of len, it can analyse stability of LI61SE,Akreos Adapt foldable intraocular lens.Results:1. Both A and B group have well eyesight(t=0.690 p>0.05).The probability of central poster opacification (χ²=4.518,p<0.05) and peripheral poster capsule wrinkle (χ²=4.085,p<0.05) in A group is higher than B group. And there is no statistical difference on peripheral poster opacification (χ²=0.016,p>0.05) and central poster capsule wrinkle (χ²=0.501,p>0.05)between A and B group. The probability of central and peripheral poster opacification and wrinkle is correlative in A group (Kappa=0.393, Kappa=0.618,p<0.05); and the probability of central and peripheral poster opacification and wrinkle is not correlative in B group(Kappa=0.068,Kappa=0.121,p>0.05).2. The pictures of intraocular lens supporting len capsule refelect that the poster capsules of implanted Akreos Adapt foldable intraocular lens are smoother and flatter than the poster capsules of implanted LI61SE foldable intraocular lens.3.The results of computer analysed reflect that the height of top wrinkle of implanted LI61SE foldable intraocular len is 9.21×10^-3mm,and the height of top wrinkle of implanted Akreos Adapt foldable intraocular len is 7.3×10^-5 mm ; the area of wrinkle of implanted LI61SE foldable intraocular len is 9.64×10^-2mm²,and the area of wrinkle of implanted Akreos Adapt foldable intraocular len is 1.33×10^-3mm².Conclusions1. The ratio of central posterior opacification and peripheral posterior wrinkle in LI61SE group is higher than AkreosAdapt group when different shaped foldable intraocular lens are implanted after phacoemulsification nearly five months. The high ratio of peripheral posterior wrinkle make the square barrier of IOL broken.We speculate the reason is that residual LECs was crawling central posterior capsule.The probability of central and peripheral poster opacification and wrinkle is correlative in LI61SE group, but it is not correlative in Akreos Adapt group.It is probable that the ratio of posterior opacification and posterior wrinkle of implanted different shaped designed foldable intraocular len is distinguished.2. For the use of the ABAQUS software of Finite Element Method, we simulated the state of LI61SE,AkreosAdapt foldable intraocular len in the posterior capsule, the AkreosAdapt foldable intraocular len is more stable in posterior capsules than LI61SE foldable intraocular lens.