Long-term Refractive Status After Bilateral Intraocular Lens Implantation In Cingenital Cataract

Objective: To analysis refractive status at 6 to 8 years old after bilateral intraocular lens implantation in congenital cataract.Methods: Records from March 2011 to April 2014 were retrospectively reviewed for 28 eyes of 14 patients who underwent bilateral cataract surgery with primary or secondary intraocular lens implantation for congenital cataract age ≤5 years.Keratometry were performed cooperatively by auto-keratometry.If the patients are not able to acquire keratometry,the keratometry 43.0D were used to calculate IOL power.According to different length of axial lengths,different IOL calculation formulas are selected.Target refractive =(7-age(y))D.The final power IOL was adjusted according to the axial lengths compared with normal children of same age.Preoperative observations included preoperative axial and preoperative corneal curvature.Surgical observations included the age of surgery,the type of surgery,the type of IOL implanted,the degree of surgery,and intraoperative complications.Observations included the best corrected distance visual acuity(BCDVA),optometry from 1 to 3 months after surgery,final follow-up optometry,axial and corneal curvature.Refractive state relatedindicators include spherical equivalent(SE),absolute refractive prediction error,anisometropia,myopia drift,and refractive error rate(D/year).Statistical analysis was performed using SPSS 22.0 Statistics.Results:1.BCDVA: The median of BCDVA at the last follow-up was 0.3(0.05,1.0).Percentage of BCDVA <0.3 were 43%,39% were from 0.3between 0.5,percentage of BCDVA >0.5 were 18%.The study had a good percentage of BCDVA,and more than half of the last follow-up of the eyes had a BCDVA of0.3 or more.2.refractive status(1)The median of SE was 0.31D(-9.5D,5.25D).22 eyes(78%)had good refractive status at 6 to 8 years old.8 eyes(28.5%)were emmetropia(-0.5D ≤ SE ≤ 0.5D).8 eyes(28.5%)were mild hyperopia(0.5< SE ≤ 3.0D),6eyes(21%)were mild myopia(-3.0D ≤ SE <-0.5D).There were 6 eyes with poor final refractive status,including moderate hyperopia(3 < SE ≤ 5D),high hyperopia(SE > 5D),and high myopia(SE <-6D)with 2 eyes,1 eye,and 3eyes,respectively.(2)absolute prediction error: The median of absolute prediction error of 28 eyes was 0.43D(0D,9D).The absolute refractive error of 16 eyes was good within 0.5D.However,there were 12 eyes with high absolute prediction error,and the absolute refractive error of the refractive index with 7 to 3D,3 to5 D,and >7D,were 7 eyes,2 eyes,and 3 eyes,respectively.There was no significant difference in absolute refractive error between the two groups at surgery age ≤ 2 years and 2 to 4 years(p=0.503),but range of the final absolute refractive error was larger at surgery age ≤ 2 years group.The final absolute prediction error of the eye axis ≤21mm group was significantly higher than theeye axis <21mm group(P=0.006).(3)anisometropia: Six patients(43%)had no anisometropia(<1.0D).6patients(43%)had mild anisometropia(≥1.0D and <2.5D).Only 2 patients were at high anisometropia(≥2.5D)with anisometropia of 4.75 D and 6.375 D,respectively.(4)Myopia drift: Only 14 eyes achieved optometry results within 3months after IOL implantation.Except for 1 eye was hyperopic,and the other 13 eyes were shift to myopia.3.Axial length: the average Preoperative axial length was 21.53 ±1.77 mm,and the average axial length at the last follow-up was 23.74±1.79 mm,which was significantly longer than the preoperative average axial length(P=0),and also longer than axial length of normal children of the same age(p=0.003).4.Corneal curvature: 10 eyes obtained Preoperative K value,the range was from 43.31 to 49.5D.The median value of the last K value in 22 eyes was44.9D(43.5D,52.50D).Among them,there were 8 eyes(28%)with corneal curvature ≥46D,and 43.0D were used to calculate the IOL degree.3 eyes were high myopia with the diopter of-8.5D,-8.25 D,-9.5D,respectively.Conclusions: 1.In this study,most cases had good refractive status in the long-term follow-up,and only a few cases had moderate and high refractive errors.2.The younger age and the shorter axial length is important reason for long-term absolute refractive error.3.High corneal curvature and slow growth of are the main causes of moderate and high refractive errors in long-term follow-up.