['To evaluate the mid-long term stability and safety of posterior chamber phakic intraocular lens (ICL) implantation for the correction of extreme myopia.', 'This retrospective study included 993 eyes of 498 patients received ICL implantation from June 1996 to December 2008. Multivariate analysis and variance analysis were used to evaluate the stability of the results and to identify risk factors of the complications.', 'Successful implantation was achieved in all patients. Spherical equivalent (SE) was (16.23 ± 4.12, mean ± SD) D before the operation and (-0.92 ± 1.22) D at the last examination. Intraocular pressure was (13.58 ± 2.93) mm Hg (1 mm Hg = 0.133 kPa) preoperatively which was (13.90 ± 3.01) mm Hg at the last examination. There was no statistical significance in follow-up (t = 0.44 ∼ 1.30, P > 0.05). Endothelial cell density was (2858.21 ± 395.13)/mm(2) before the operation and (2567.19 ± 423.45)/mm(2) at last examination. Pupillary block glaucoma occurred in 2 eyes (0.2%) at two hours and 1 eye (0.1%) at one month after the operation. Three eyes developed anterior cataracts between 6 months to 1 year after ICL implantation and another 2 eyes subcapsular opacification at semi-peripheral regions occurred 4 years after the operation, and was not related with age, SE and vaults (F = 2.42, 1.98, 0.81, P > 0.05). Macular puckers were found in 5 eyes (0.5%) 1 year postoperatively, including 2 eyes developed choroidal neovascularization and received PDT, best corrected visual acuity lost more than 2 lines. Retinal detachment occurred in 2 eyes at 1.5 years after the operation. Acute iritis happened in 1 eye (0.1%) and chronic iritis in 1 eye (0.1%) which combined with slight pupil distortion and elevation of intraocular pressure. Iris stroma atrophy and pupil distortion were found in 2 eyes (0.2%).'] Does [ Mid-long term follow-up result in correction of extreme myopia by posterior chamber phakic intraocular lens ]?