While cataract surgery and intraocular lens implantation is one of the most common and safest surgeries performed globally, serious complications can and do occur. Even the best and most experienced cataract surgeons can occasionally have a complication, as with any surgery in the body. If, for instance, the lens capsule ruptures during the procedure, fragments of the native lens or the intraocular lens implant itself can fall back into the vitreous cavity. Pars plana vitrectomy surgery is used to repair retained lens fragments or dislocated lenses. Intraocular lens implant removal and/or repositioning may also be necessary at this time. This procedure can be performed after the initial cataract surgery once the intraocular inflammation lessens with the help of topical medications. If the intraocular pressure is elevated, then this surgery may need to be performed sooner.

Cystoid macular edema (CME), or inflammatory swelling of the macular portion of the retina, can cause blurry vision, even in uneventful/successful cataract surgery. This can be treated with topical medications or with steroid injections in or around the eye. This can be diagnosed with the help of fluorescein angiography and optical coherence tomography (OCT).

Endophthalmitis is an infection inside the eye. It can occur after any intraocular surgery and can be due to a number of many different microorganisms. Inflammation and vision loss can occur in the post-operative period. This can lead to scarring, retinal detachment, and permanent vision loss. Treatment includes injections of antimicrobials into the eye (intravitreal injection) which can be done in the office. More severe infections may require vitrectomy surgery. The prognosis depends on the severity of the infection, the duration of infection, and the type of microorganisms present.

Choroidal hemorrhage is a serious complication where blood fills the space beneath the choroid layer of the eye which is the level beneath the retina. Once this blood liquefies, vitrectomy with or without drainage of this hemorrhage can be attempted.