Clinical Services

Scleral fixated IOL for subluxated lens

Background Information:

Cataract surgery is the most common operation performed by ophthalmologists. Although it has a very high success rate, certain complications may occur. Intraocular lens (IOL) malpositions range from simple IOL decentration to luxation into the posterior segment. Subluxated IOLs involve such extreme decentration that the IOL optic covers only a small fraction of the pupillary space. Luxation involves total dislocation of the IOL into the posterior segment. Decentration of an IOL may be the result of the original surgical placement of the lens.

Pathophysiology:

IOL dislocation can be subdivided into early and late dislocation. Early dislocation refers to dislocation occurring within 3 months of cataract surgery, whereas late dislocation occurs more than 3 months after cataract extraction.

Late IOL dislocation has been noted to occur more frequently than previously thought.Late IOL dislocation results from zonular weakness since the IOL is adequately fixed within the capsular bag. Several risk factors, including pseudoexfoliation syndrome, trauma, prior vitreoretinal surgery, and connective tissue disorders, have been associated with zonular weakness. In a retrospective case series of 86 late IOL dislocations, the IOL dislocated on average 8.5 years after phacoemulsification and IOL implantation.These same authors reported that patients with any type of IOL were at risk for late in-the-bag IOL dislocation.

The IOL rarely dislocates completely onto the retinal surface. It usually lies meshed into the anterior vitreous with one haptic still adherent to the capsule or iris. It may cause a vitreous hemorrhage by mechanical contact with ciliary body vessels. The IOL may be related to retinal detachment or cystoid macular edema secondary to vitreous changes and may cause pupillary block or corneal contact with secondary corneal edema. On many occasions, it does not cause any complications and may be left alone if the patient is able to use aphakic spectacles or contact lenses.