Background Bilateral congenital cataract is one of the vision-threating diseases during infant age.Intraocular lens (IOL) implantation is an ideal refraction correction method for children who have already received bilateral cataract extraction.However,the timing and effectiveness of secondary IOL implantation are still under debate.Objective This study was to analyze the visual changes and affecting factors before and after secondary IOL implantation and explore the operative timing.Methods The clinical data of 58 eyes of 29 patients who received bilateral cataract extraction-refractive correction and vision training-secondary IOL implantation in Peking University People's Hospital from January 2012 to December 2014 were retrospectively analyzed.All the patients received bilateral cataract extraction and posterior capsulotomy with anterior vitrectomy during their first year of life firstly,followed by the wearing of refractive spectacles or visual training,and secondary IOL implantation was simultaneously performed until ＞2 years old.Best corrected visual acurity (BCVA) (LogMAR) was examined at 1 week before and 3 months after secondary surgery under the mydriasis.Changes,distribution alternation of BCVA and the relationship of visual prognosis with preoperative visual acuity were evaluated.Results The average age at surgery of the patients was (3.26±2.07) months and that at secondary IOL implantation was (4.79± 1.38) years,with the operative interval of (4.28± 1.33) years.The BCVA before and after secondary IOL implantation was 0.790± 0.422 and 0.570±0.307 respectively,showing a significant difference between them (t =3.223,P＜0.001).The number of eyes with BCVA ≥ 0.5 after surgery was significantly more than that before surgery (x2=53.931,P＜0.001).A positive correlation in unilateral BCVA was seen between before and after secondary IOL implantation (R2 =0.232,F =17.037,P ＜ 0.001).Conclusions A systemic management of bilateral cataract extractionrefractive correction and vision training-secondary IOL implantation for congenital cataract is beneficial to BCVA improvement and amblyopia treatment,and it should be performed as early as possible on the premise of ensuring the safety of life.Secondary IOL implantation should be timely carried out for aphakic children with poor compliance and outcomes during vision training after congenital cataract extraction.