Posterior Capsular Opacity
Also referred to as: Posterior Capsular Haze; Secondary Cataract
A posterior capsule opacity is the presence of a hazy membrane (capsule) just behind an intraocular lens implant. This condition is sometimes referred to as "secondary cataract," although the term is actually a misnomer. Once a cataract is removed, it does not recur.
Ophthalmologists generally prefer, at the time of cataract surgery, to place the intraocular lens implant in the same anatomical position that the natural lens (cataract) had, i.e., within the capsular bag. The natural lens of the eye is contained within a thin membrane known as a capsule. When the adult cataract is removed, the ophthalmologist makes every attempt to maintain the integrity of the capsule, such that the lens implant can be placed within it. The anterior part of the capsule is opened to remove the cataract, but the posterior side of the capsule is left intact to support the lens and prevent vitreous humor from entering the anterior (front) chamber of the eye. Postoperatively, however, about 20% of patients with intact posterior capsules will develop haziness of the capsule known as posterior capsule opacity, which results in blurry vision. This is due to the growth of lens epithelial cells on the capsule, which frequently remain present following cataract surgery. If the condition progresses significantly, vision may be worse than it was prior to cataract surgery in some cases.
Fortunately, with the YAG laser, treatment of posterior capsule opacity is safe, effective, painless, and can often be performed as an in-office procedure. In this procedure, known as YAG laser capsulotomy, the hazy posterior capsule is removed from the visual axis (line of sight) using the advantage of the laser. This allows the surgery to be completed without making an incision or "touching" the eye. The patient must be cooperative, however, and very uncooperative patients (e.g., children, mentally retarded patients) may require sedation for the procedure, or the posterior capsule can be opened in a second surgical operation under general anesthesia.
A YAG laser capsulotomy does pose additional risk, however, overall the procedure is extremely safe. The most important risk of the procedure is retinal detachment. Statistical analyses suggest that the lifetime risk of retinal detachment following cataract surgery in the U.S. is about 1%. That number rises to about 2% following YAG laser capsulotomy. This point should be clearly understood by all patients who require the procedure. Most patients who develop retinal detachment will have a good outcome, assuming they present to the ophthalmologist promptly when symptoms first begin, and treatment is not delayed. However, a small percentage of patients will have substantial and permanent vision reduction. In general, patients should report symptoms of floaters, light flashes, and a curtain-like vision loss to their ophthalmologist immediately..