A cataract is a clouding of the crystalline lens, i.e. the structure that allows the focus of the image. This process is physiological in most cases and usually begins after the age of 60. The symptoms suffered by the patient include decline in visual acuity, eye myopization and dyschromatopsia (sensation of seeing yellowed objects).
A cataract is an alteration that cannot be solved by drug therapy, but only by surgery. Nowadays cataract surgery is an outpatient procedure and is executed under local anaesthesia (instillation of drops directly into the eye to be operated); as a rule, the duration of the operation varies between 10 and 15 minutes, and a few hours later it is already possible to appreciate observe the results achieved. This ease of execution from the point of view of timing should not mislead and suggest that it is a trivial operation. In fact it should be properly planned, executed and monitored postoperatively to achieve the best possible results.
There are different types of cataracts: age related, trauma related, secondary (which will be discussed below) or due to metabolic dysfunctions (e.g. diabetes). The reason behind cataract is the ageing of the crystalline lens; the cells that make up its content proliferate and change their appearance, thereby altering its internal architecture too. It would seem that the phenomenon that leads to such anatomical and functional changes of the cells is a process of oxidation of certain proteins. Besides, risk factors have been found for the onset of cataract, such as genetic predisposition and poor nutrition.
These changes result in a clouding of the crystalline lens, a gradual process that can be divided into 4 phases, namely: initial stage, intumescence, maturity and hypermaturity. The surgical procedure is performed when the cataract is sufficiently mature; performing surgery at the stage of hypermaturity (too late) is more complicated because the material to be removes has become harder. Only in cases in which surgery is not aimed at an improvement of visual acuity it is possible to operate in the early stages of cataract; these are cases in which we find coexisting diseases, such as inflammatory states of the eyeball or retinal diseases, which may worsen in the presence of cataracts. Surgery is never performed simultaneously in both eyes; it starts from the eye with worse visual acuity and between an operation and the other it is recommended to wait for at least 15 days or in any case for a complete recovery of sight. This short interval of time allows the rehabilitation to take place in a short period for both eyes, therefore reducing any discomfort.
The surgical technique of choice is phacoemulsification. The eye is numbed with drops and an incision is made on the cornea to allow access to the crystalline lens. The crystalline lens is fragmented and aspirated. After this procedure, an artificial lens can be implanted and the operation id over. As a rule, no suturing stitches are applied (except in exceptional cases). As time passes, the younger and more reactive is the person, the more likely the onset of a secondary cataract becomes. In reality, it is only a posterior capsule clouding of the old crystalline lens. This capsule is not removed because it serves to act as a support for the artificial crystalline lens. Unlike a cataract which ahs already been operated, for this it will not be necessary to return to the operating room, but only to perform a small hole, from the outside, by means of a laser beam. This procedure is called YAG Laser capsulotomy and lasts a few minutes, performing a sort of lens cleaning. This is a painless procedure.