After cataract surgery with lens implantation, the thin natural membrane behind the lens can become grey and thickened – this is posterior capsule opacification (PCO) and it can cause gradual blurring of vision after cataract surgery. It can occur any time after cataract surgery. Roughly 10-15% of patients will develop some form of PCO after cataract surgery, so it is relatively common.
The only treatment for PCO is to remove the central posterior capsule with a focused laser. This procedure (laser capsulotomy) is relatively quick and safe. Quoted risks include floaters, swelling of the macula, transient eye pressure rise, inflammation, and retinal detachment, but serious or sight-threatening risks of laser capsulotomy are extremely rare.