| Background and PurposeCongenital cataract is that a part or all of the lens become turbid before or after birth,which is caused by congenital genetic or developmental disorder.It is a common eye disease in children,which is an important factor to cause blindness and amblyopia in children.The study results on cause of blindness in Tianjin,Shanghai and Beijing suggest: congenital cataract is the most common cause of blindness in children,taking up about 22%~30% in our country,and it is the second cause of our country.The incidence of congenital cataract rate is about 0.5% ~ 1.5%.Children with congenital cataract,due to the unclear visual path witch affects the normal development of vision,can make be the deprivation amblyopia,therefore,the children with congenital cataract which can impact their visual development should be operated early.The clinical study showed that the ideal treatment method of congenital cataract is surgery,namely phacoemulsification,posterior capsulotomy with anterior vitrectmy and intraocular lens implantation.However,because of the special nature of the visual system of infants and young children,the eyeball is still in the developmental stage,and the refractive state is unstable,especially in children under 3 years old.And the heavy postoperative reaction relatively and the poor compliance of children may be associated with amblyopia and increases the complexity and risk of congenital cataract surgery.The intraocular lens implantation surgery,at present,more scholars have suggested that the intraocular lens implantation is more appropriate after 2 years old.There is still a controversy that intraocular lens implantation is safe and effective.Further clinical practice and time testing are needed.With the continuous development of congenital cataract surgery,anesthesia and microsurgery technique for congenital cataract,early cataract extraction and intraocular lens implantation is the main treatment measure of congenital cataract.Therefore the ideal IOL implantation,ensuring long-term postoperative visual effect,and reducing the anisometropia after surgery is the problems we must solve as soon as possible.At present,the problems we encountered include the following:The first of all,intraocular lens calculation is prone to large errors for younger children,there are statistics showing intraocular lens degree error of about-4.06D~+3.86 D within 1 years of age.The second,there is no formula for calculating intraocular lens about children.Thirdly,the measurement of biological parameters(including the axial length and corneal curvature)of the eye in children is difficult.Although,we can use IOL-Master or portable automatic measuring tools to measure the state of anesthesia in children in some of the better medical facilities,the measurement of biological parameters still can not be achievedin some developing countries or relatively backward hospitals.In addition,the presence of corneal opacity,trauma caused by corneal deformation and other conditions also affect the measurement of corneal curvature.In these cases,the normal adult corneal curvature 42.5D~44.0D is chosen to estimate the degree of IOL.But this will have a greater error for younger children.The main factors that affect the refractive changes of the eye include the axial length,corneal curvature and the development of the lens.Within 3 years,the eyeball is still in the stage of rapid development,the axis of eye and corneal curvature are in a process of changing.After cataract extraction and intraocular lens implantation,the equilibrium state of refractive changes in the development process is broken.Have a certain effect of aphakia and pseudophakia or axial length and corneal curvature development,the impact will not affect the eye refractive status?Of course,there are quite a few reports on the development of in normal eyes and eyes of cataract.However,the results of clinical trials on the changes of axial and corneal curvature after cataract surgery in infants were not completely consistent.The clinical study of infants with less than 3 years old.In this study,we observed and analyzed the changes of ocular axial length,corneal curvature and refractive index in children with congenital cataract,to further understand the congenital cataract,aphakic eye,intraocular lens eye axial length and corneal curvature,to provide the basis about surgery in the clinical work of the timing,calculation and selection of intraocular lens,and intended residual refractive power postoperation for the junior hospital reservation where equipment conditions are relatively poor.ObjectsSubjects were selected from January 2014 to December 2015 in our department of diagnosis and treatment of 3 year old children with congenital cataract in 158 cases of 246 eyes.Inclusion criteria included simple binocular or monocular congenital cataract.The age of the patients was 3 years old.The operative procedures included for younger than 2 years old in phacoemulsification,posterior capsulotomy,and anterior vitreous body resection,underwent two intraocular lens implantation after 2 years old.For 2 year old children underwent phacoemulsification,posterior capsulotomy,and anterior vitreous body resection combined with intraocular lens implantation.2 year old children underwent phacoemulsification,posterior capsulotomy,and anterior vitreous body resection combined with intraocular lens implantation.MethodsAccording to the age of initial surgery patients were divided into 4 groups: group A: 3 months ~ 6 months;B group: 6 months ~ 12months;C group: 12months~24 months;group D: 24 months~36 months.All patients were followed up for 1 years,recording intraocular pressure,axial length,corneal curvature,subjective spherical equivalent degree and follow-up complications under optometry in 3 months,6 months and 1 years after surgeryafter surgery.When children with uncorrected visual acuity,best corrected visual acuity(pictograph)The data were transferred to a standardized form and analyzed using SPSS 21.0.Data were analyzed using SPSS 21.0 statistical analysis software(IBM,USA).Kolmogorov-Smirnov methods were used assess the normality of the data.Normally distributed data were analyzed via the independent Student’s t-test.Data that were not normally distributed were analyzed by the rank sum test.P value less than 0.05 was considered statistically significant.Results1.After 3 months,the axial length of the five groups were 18.82 + 1.219 mm,20.61 + 0.796 mm,21.28 + 0.987 mm,21..60 + 0.836 mm,21.94 + 0.992,compared with the preoperative growth were 0.818 + 0.387 mm,0.682 + 0.289 mm,0.504 + 0.264 mm,0.353 + 0.450 mm,0.266 + 0.344 mm.The growth of the axial length were 1.561 + 0.473 mm,1.132 + 0.439 mm,0.963 + 0.395 mm,0.713 + 0.569 mm,0.464 + 0.488 mm after 6 months,after 1 years the growth were 2.554 + 0.588 mm,1.728±0.592 mm,1.080±0.513 mm,0.859±0.704 mm,0.768±0.520 mm.The difference was statistically significant(P<0.05).Comparison between five groups:After 3 months,the growth rate of A,B,C was higher than D and E,the difference was statistically significant(P<0.05).The growth rate of A was higher than that of B group,and D was higher than E,but the difference was not statistically significant(P>0.05).After 6 months and 1 years,the growth of A,B was higher than C,D,E,the difference was statistically significant(P<0.05),A>B,C>D>E,but the difference was not statistically significant(P>0.05).2.The axial growth of operative eye of unilateral cataract was higher than the healthy eye for five groups after operation,but the difference was not statistically significant(P>0.05).3.After operation,corneal curvature of A,B,C,D groups were significantly different with the one before operation(P<0.05).Compared with before operation,corneal curvature of E group decreased gradually,but there was no statistical significance.There was significant difference in corneal curvature before and after operation(P<0.05).Comparison between five groups,the changes of A,B two were higher than C,D,E after operation 3 months,and C was higher than E group,but the difference was statistically significant(P<0.05).The change rate of C was higher than that of D group,and D higher than that of E,but the difference was not statistically significant(P>0.05).6 months and 1 years after operation,the change rate of A was higher than C,D,E,and the difference was statistically significant(P<0.05);And A>B,C>D>E,but the difference was not statistically significant(P>0.05).B was higher than E,and the difference was statistically significant(P<0.05);And B>C>D,C>D>E but the difference was not statistically significant.4.The corneal curvature of operative eye of unilateral cataract was not statistically significant to the healthy eye for five groups after operation(P>0.05).In each stage of postoperative corneal curvature changes of five groups is consistent with that of the healthy eyes.The corneal curvature decreased gradually,and the change of corneal curvature decreased with age.There was no significant change of corneal curvature in group E(24-36months).5.The changes of refractive index in each group after operation were-2.89 + 0.975 D,-2.51 + 0.732 D,-2.28 + 0.837 D,-1.94 + 1.035 D,-1.85 + 0.897 D,and the difference was statistically significant(P=0.015).Multiple comparisons between groups,the changes of A,B,C were higher than D,E,and the difference was statistically significant.Among them A>B>C,D>E,but the difference was not statistically significant.The refractive index of each group was shifted to myopia,and the trend of metastasis was slow with the increase of age.6.There was no significant difference in the change of refractive index in patients with unilateral cataract compared with healthy eyes(P>0.05).The refractive index of each group was shifted to myopia,and the trend of metastasis was slow with the increase of age.7.Group of children with bilateral congenital cataract and unilateral cataract,and the results showed that there was no significant difference in the axial length,corneal curvature and refractive index of the patients with unilateral and bilateral congenital cataract after surgery(P>0.05).The eyes of unilateral cataract were bigger than that of bilateral congenital cataract in the axial length and refractive index.8.No secondary glaucoma,retinal detachment,after-cataract,IOL dislocation occurred during follow-up time.1 cases were lost In group E,and In group C,2 cases were excluded because the children could not match the data and data not included in statistical analysis.ConclusionThe growth rate of axis was faster before 18 months,and then grown slowly.The axial growth of operative eye of unilateral cataract was higher than the healthy eye.Changes of corneal curvature were greater in children with 12 months,and then slowly to the normal level in 24 months old.Thee is a trend of the degree of refractive changes after cataract surgery.And it becomes slow with the growth of age.The coordinated development of unilateral congenital cataract patients can obtained after cataract surgery. |
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