Over 90% of the people above the age of 65 lose their vision because of cataract, a condition in
which the natural lens of the eye becomes dense and cloudy.
Posterior polar cataract
Another form of cataract known as the posterior cataract may develop in the central posterior part of
the lens in some people. Posterior polar cataract resembles a round, disc shaped opaque mass. The
location of posterior cataracts makes it tricky for the surgeon to remove the cataract as the
procedure has to be performed without compromising the thin membrane that encapsulates the eye.
This membrane is very important as the intraocular lens will be implanted within this membrane
after the cataract is removed.
The earlier posterior polar cataracts are diagnosed, the better it is for the patient.
Treating posterior polar cataracts with laser cataract surgery
The common surgical methods used in removing congenital cataract cannot be used in this case
because of the sensitivity of the location. Even a slight error can cause the membrane to tear.
This means that stress on the membrane during the surgery must be minimized. This is quite
challenging since the fibers of the polar cataract strongly adhere to the membrane.
The first step before surgery is to completely assess cataracts and the extent to which it is adhered to
the membrane. Once this achieved, the surgeon gets a better idea about how to proceed with the surgery.
The patient is first administered local anesthesia and the eye is then positioned as required with the
operative microscope. Corneal incisions are made as in the case of a normal cataract surgery and a technique called
hydrolineation is used to protect the lens. Hydrolineation is used to reduce the portion of the
affected lens that has to be removed. Hydrolineation creates a cushion like structure around the
membrane that protects it from undue stress.
There is evidence that laser cataract surgery is safer for these patients. By 'pre-softening' the cataract, it may be maneuvered more easily. This creates less stress on the membrane, leading to less of a chance of tearing it.
Once hydrolineation has been achieved, the affected part of the lens is removed with utmost
caution. After the removal of the mass, the area is irrigated very carefully. Irrigation is directed
obliquely in order to avoid stress on the lens membrane.
The hard part is still not over. The surgeon has only removed part of the affected lens. There is still
a large portion of lens fibers adhered to the membrane itself. The fibers are loosened as much as
possible by irrigating it. The remaining fibers are removed through aspiration.
Soon after this, the intraocular lens is implanted into the lens membrane.
The eye takes about six weeks to completely heal. The doctor may prescribe certain medications
during this period.