Inclusion and exclusion criteria
Inclusion and exclusion criteria: (i) The subjects should be cataract infants younger than 2 years (P) who received cataract extraction with primary IOL implantation (I) or primary aphakia (C); (ii) The clinical outcomes on postoperative VA, complications (glaucoma, strabismus, nystagmus and visual axial opacity) (O) should be evaluated; (iii) Given the age at the surgery and the age at the last visit were significant factors for the postoperative outcomes in congenital cataract patients, studies in which the age at the surgery or last visit in these two groups did not match were excluded; (iv) Studies without detailed outcome on the postoperative visual performance were excluded; (v) Studies reporting data on individual patient rather than individual surgery eye were excluded; (vi) (potentially) overlapping study populations that reported same outcome were excluded; (vii) Non-English publications were excluded.