Ophthalmic examination
A complete ophthalmic examination, including visual acuity (VA), slit-lamp biomicroscopy and dilated fundoscopy, was carried out preoperatively (within 14 days of surgery) and at 3 weeks, 3 and 6 months postoperatively. Visual acuity using a protocol refraction and ETDRS vision testing at 4 m was measured by masked research staff preoperatively and at 3 and 6 months postoperatively.