Another unusual problem that can develop after cataract surgery is incomplete removal of the cataract lens with retained lens fragments in the eye. Often ophthalmologists use the analogy of operating on an egg when describing cataract surgery. The Yolk and most of the White of the egg is removed leaving a clear shell or sac called the posterior capsule behind. Usually a plastic lens implant is placed within this sac. In about one in fifty cases this delicate posterior capsule may break during the cataract surgery. In a small proportion of these, part or all of the cataract can be lost into the central eye cavity. These pieces of the cataract or retained lens fragments depending upon their size and associated problems may or may not require removal from the eye by a of the vitreo-retinal surgeon. These fragments can lead to high pressure, inflammation, and swelling of the retina if not removed with in a few weeks. However not every patient with retained lens fragments requires additional surgery. A vitrectomy or removal of the jelly like substance from the eye is performed to remove these lens fragments. Usaually, 80% of patients do recover reading vision.