A cataract is the loss of transparency of the crystalline lens, the eye’s natural lens located behind the pupil. Rays of light pass through this lens to reach the retina, where images are formed. If the lens becomes less transparent and obstructs the passage of light to the retina, the patient suffers from a progressive loss of vision.
They may be:
Congenital: caused by genetic changes resulting from complications during pregnancy, such as rubella or toxoplasmosis, use of certain medications or malnutrition of the mother.
Acquired: caused by diseases such as diabetes, the gout or hypothyroidism, as a result of trauma, poor exposure to lightning, poisoning and prolonged corticosteroid treatment or high doses of some anti-inflammatories.
However, the main cause of cataracts is the natural aging of the eye, being cataracts mostly diagnosed after age 65. Usually the loss of the crystalline lens transparency is progressive and presents some previous symptoms such as: Blurred Vision, Luminous Halos and Glare, Fluctuation of Vision or Frequent Need to Update Correction Glasses. Cataracts manifest through decreased vision, of greater or lesser amplitude, depending on the location and extent of opacity of the crystalline lens. Whether congenital or acquired, lack of adequate treatment may lead to total vision loss.
A congenital cataract is a clouding of the crystalline lens of the eye that is present at birth, preventing the child from seeing. Cataracts can impair vision, if they are large and completely cover the pupil (the central area of the eye, through which light enters).
They can be unilateral or bilateral and can be accompanied by ocular abnormalities (corneal and retinal disorders) and are often hereditary. They can also be caused by Intrauterine Infections, Chromosomal Syndromes, Metabolic Disorders and Renal Diseases.
The most common technique for operating cataracts is called phacoemulsification, which is performed through an incision measuring less than three millimetres, through which the opaque contents of the eye's crystalline (natural) lens is removed. The cataract is conventionally broken up by ultrasound, although in certain situations we can use Femtosecond Laser, which is also used to make the incision.
The laser is especially useful in complex cases, as it offers a high degree of precision. Once the cataract has been broken up, a tube then aspirates it and the intraocular lens is fitted in the sack enveloping the crystalline lens to avoid the need for correction with thick glasses.