Ectopia lentis is the medical term for the dislocation or displacement of the eye’s natural lens. A dislocated lens is usually the result of trauma to the eye, but some infants are born with dislocated eye lenses and there are several genetic disorders that can cause it, such as Marfan syndrome.
Key to image: In the image, there is a dilated normal circular pupil as marked by the small green arrows. The small red arrows show the bottom portion of the natural lens (shaped exactly like an M & M) as it has been dislocated upward (technically this is lens subluxation).
Getting hit in the eye by a baseball or golf ball are common causes of a dislocated lens. This kind of trauma can also disrupt or damage the zonular fibers. The zonules are tiny thread-like fibers that hold the eye’s lens in place. The zonules also move the ciliary muscles to help the lens change focus for near vision.
Dislocated Lens | Symptoms
The symptom of ectopia lentis is blurred vision. The degree of the blurring depends on how dislocated the lens is and the type of dislocation. A partially dislocated lens may not cause any symptoms. If the supporting structures are damaged, the iris (circular portion of the eye that gives the eye its color) may also lose support and quiver.
In some cases in which the dislocation is minimal and there are no significant visual changes, so no treatment is necessary. If the vision is affected, surgery will be necessary. There are several surgical techniques for correcting a dislocated lens. An artificial lens can be implanted, but if the surrounding eye structure is damaged the surgery is more complex and complicated.
Removal of the natural lens and implantation of an artificial lens is complicated when the blunt force trauma to the eye tears the supporting eye structures (zonules). If the lens is barely hanging in position, it may be necessary to consult a retina specialist who can remove the lens from behind (a pars plana approach) to keep the lens from falling back into the eye.
If the lens has fallen back into the vitreous cavity, then a vitrectomy will be necessary, and the lens will need to be broken up into tiny pieces to be removed. This surgery is done by a retinal specialist. If there is not enough structural support for an implanted artificial lens, the artificial lens can be placed in front of the iris and sutured into place behind the iris.
In some cases, an artificial lens is not implanted and instead a contact lens is worn.
Most patients do well and at least 85% have 20/40 or better visual acuity after treatment. In patients with a pre-existing condition such as a corneal disease or a history of retinal detachment or diabetic retinopathy, then the outcome is not as favorable.