Intraocular lens dislocation

Cataract surgery is one of the most common and successful surgical procedures performed today. Over the past decade, the risk of serious complications has decreased with advances in surgical tools and techniques. During the procedure, the cataract (cloudy lens) is removed and a clear intraocular lens (IOL) is placed in the eye. Rare complications include intraocular lens (IOL) displacement, where the lens becomes displaced into the vitreous humor. 

Symptoms

The most common symptom of a displaced intraocular lens is a change in vision. The degree to which vision is affected will depend on the severity of the displacement.

This can manifest in the following ways:

• Blurry vison
• Double vision 
• Seeing part of the lens

IOL dislocation can also lead to other complications such as retinal detachment, hemorrhage, intraocular inflammation, macular edema, glaucoma, and corneal edema.

Causes

During most cataract surgeries, the intraocular lens is placed inside the capsule, a sac-like structure in the eye that previously contained the cloudy lens. In some cases, this extremely thin capsule or the fibers that hold it in place become torn, and the support of the intraocular lens is compromised.

IOL displacement can occur from days to years after surgery and may be the result of factors during the initial surgery, trauma to the eye, or diseases that affect the stability of the capsule.

Risk factors

• Trauma
• Previous vitreous surgery
• Pseudoexfoliation syndrome 
• Connective tissue disorders
• Inflammation of the eye (uveitis)

Diagnosis

Your retina specialist will perform a thorough eye examination, including a careful examination of the peripheral retina.

The displaced intraocular lens is sometimes photographed to document the extent of the problem. 

Treatment and outcome

Based on the characteristics of intraocular lens displacement, there are many different approaches to correcting this problem.

In cases where the intraocular lens displacement is minimal and does not have a major impact on vision, your doctor may not recommend any treatment.

When vision is affected and the patient is experiencing symptoms, surgery is performed. In this surgery, the vitreous that fills the posterior cavity of the eye is removed (vitrectomy) to prevent traction on the retina.

Techniques for repairing a displaced intraocular lens fall into 2 categories. Your doctor will choose the most appropriate one depending on the type of intraocular lens and the anatomy of your eye:

• Salvage/replacement of the intraocular lens: The intraocular lens is retained and repositioned in a more stable position. The ability to use the existing lens is based on many factors, including the type and condition of the intraocular lens.
• Intraocular lens exchange: The intraocular lens is removed and a new intraocular lens is inserted.

Possible complications of the procedure include retinal detachment, uveitis (inflammation inside the eye), infection, glaucoma, bleeding, and re-displacement of the intraocular lens.