20/11/2015
New advances in cataract surgery
November 20, 2015 • 1 View • 1 Like • 0 Comments
Modern techniques permit small incision cataract surgery. The removal of the cataract through a small 2,2 mm incision without the need for any sutures translates to painless surgery and a very rapid healing with excellent visual results.
I like to compare the cataract lens to a trampoline. The lens is located centrally in the eye behind the color or iris of the eye. It is held in position by small bands of zonules, much like the springs around a trampoline. During surgery a thin needle is used to make a small opening in the front of the lens. The hazy content is broken into small pieces and removed by a suction, much like a vacuum cleaner. An empty shell is left, much like an envelope, and the plastic lens that restores vision is placed inside this envelope.
The support of the surrounding zonules around the periphery of the lens are very important. Without this support the new lens will not be stable and centrally located, therefore the visual result will be compromised.
In the early days of cataract surgery, around 30 years ago, the whole lens was removed, not only the content of the lens. The incision was large, necessitating the use of sutures. The visual rehabilitation was long and the sutures were cut only after a month.
If the zonules around the lens are weak there is the risk that the whole lens needs to be removed, i.e. the older type of cataract surgery, because there is no support for the implanted lens. The zonules are sometimes weak for unknown reasons, but it is also associated with previous trauma to the eye, as well as conditions like Marfans syndrome and pseudoexfoliation. Newer technologies help to lend support to the lens, permitting completion of the cataract surgery through a small opening with all the benefits of modern surgery. Capsular tension rings are thin plastic rings that are inserted within the envelope of the empty lens (called the capsule of the lens), lending support by stretching the envelope from the inside. This support might not be good enough if the zonules are weak around much of the circumference of the lens. This is known as phacodonesis. Special support is needed in these cases. Capsule hooks are very specialized small plastic hooks that are used to capture the edge of the capsule to replace the support of the absent zonules. The use of a specialized capsular tension ring, called a Cionni ring,lends permanent support. It has a small opening that permits a small suture to be used to permanently fixate the capsule with the new lens. All these maneuvers allow me to still perform small incision cataract surgery, even in cases where the cataract is poorly supported. This expands the advances of modern surgery to all patients with a speedy recovery and excellent visual result.