A dislocated intraocular lens (IOL) after cataract surgery is rare and occurs in less than 3% of cases, but it can be a serious complication that may require surgery to repair.
The image on left displays the thread-like fibers, called zonules, that hold the lens in place. They attach to the outer capsule or shell of the lens. The zonules suspend the lens and keep it centered. The implant, shown on the right, is actually placed inside this outer shell or “capsular bag” during cataract surgery.
Categories of IOL Dislocation
There are two categories of a shifted or dislocated IOL. The first happens soon after cataract surgery and is caused by a break in the zonules—which are a ring of tiny thread-like fibers that support and hold the lens capsule in place. The zonules are made of fibrillin, a connective tissue protein. Things that can weaken the zonules are connective tissue disorders, a history of previous eye surgeries, trauma to the eye, and the use of prostate medication.
The second category of lens dislocation happens gradually over time as the zonules weaken and cause the lens to shift away from the center of the pupil. This happens more often in patients with a history of eye trauma, multiple eye surgeries, especially retinal detachment repair, and complicated original cataract surgery.
Symptoms Dislocated Intraocular Lens
The most common symptom is a change in vision. The change in vision depends on how severe the dislocation is. Vision in the eye with a dislocated IOL tends to be very blurry. However, if the lens is only slightly out of position, then there may be a ghost image or double image at night when light passes through the pupil around the edge of the lens.
Treatment depends on the severity of the dislocation. Some dislocations are minor and visual acuity is still good. In these cases, only observation is necessary until the lens further dislocates.
If the lens has dislocated enough to cause blurry vision surgery is necessary. Sometimes the original lens can just be repositioned and in other cases it requires a new lens that is designed to be sutured to the wall of the eye (sclera) or to the iris.
Sometimes a lens has fallen into the vitreous cavity and a vitrectomy is required. A vitrectomy is the removal of the vitreous jelly inside the eye so the displaced lens can be removed. This surgery is done by a retinal specialist.
Outcome and Follow-Up
As with all surgeries there is the possibility of complications, but most patients with IOL repositioning or IOL replacement do quite well and visual acuity in at least 85% of the cases is 20/40 or better. Each patient is different and your surgeon will discuss your individual case and possible outcome with you before your surgery.
Postoperative management after IOL repositioning or replacement is similar to the postoperative care for routine cataract surgery. The medications are the same and most patients can resume normal activities the day after surgery.