An<unk>  <unk>  is an implanted<unk>  in the eye, usually replacing the existing crystalline<unk>  because it has been clouded over by a cataract, or as a form of refractive surgery to change the eye's optical power. It usually consists of a small plastic<unk>  with plastic side struts, called haptics, to hold the<unk>  in place within the capsular bag inside the eye.<unk> s were traditionally made of an inflexible material (PMMA) though this largely been superseded by the use of flexible materials.  Most<unk> s fitted today are fixed monofocal<unk> es matched to distance vision.  However, other types are available, such as multifocal<unk> s which provide the patient with multiple-focused vision at far and reading distance, and adaptive<unk> s which provide the patent with limited visual accommodation.
Insertion of an<unk>  for the treatment of cataracts is the most commonly performed eye surgical procedure. The procedure can be done under local anesthesia with the patient awake throughout the operation.  The use of a flexible<unk>  enables the<unk>  to be rolled for insertion into the capsule through a very small incision, thus avoiding the need for stitches, and this procedure usually takes less than 30 minutes in the hands of an experienced ophthalmologist. The recovery period is about 2-3 weeks.  After surgery, patients should avoid strenuous exercise or anything else that significantly increases blood pressure.  They should also visit their ophthalmologists regularly for several months so as to monitor the implants.<unk>  implantation carries several risks associated with eye surgeries, such as infection, loosening of the<unk> ,<unk>  rotation, inflammation, night time halos.  Though<unk> s enable some patients to have reduce dependence on glasses, most patents still rely on glasses for driving and reading.
Intraocular lens
Arc eye
Fundus 
Nasolacrimal duct
Eyelid
Lacrimal canaliculi
Eye circles
Fundal height