The last report of the World Health Organisation refers that there are currently one billion people suffering from visual impairments that could have been prevented or are still treatable.
Cataracts are one of the main examples. Cataracts affect about 300 million people and are responsible for 50% of the existing cases of blindness worldwide.
A cataract is a partial or total opacity of the crystalline lens of the eye, which is located immediately behind the pupil. The eye lens in normal conditions is transparent, allowing light rays to pass through and focus on the retina, thus obtaining a clear image. When the eye lens loses its transparency, it results in impairment in visual quality and, subsequently, a decrease in the patient’s vision.
There are several causes for the appearance of cataracts, the main one being related to the physiological process of ageing. Most people over the age of 60 often experience cataracts to some degree. Other less frequent causes include injuries and prolonged use of corticosteroids. People with diabetes or shortsighted tend to have cataracts earlier.
Symptoms are various and depend on the type and opacity degree of the lens; distant vision becomes cloudy, there is a decrease in the contrast between objects and colours, poor night vision, difficulty in reading or double vision when only one eye is open. Evolution may be rapid (in a few months) or progress slowly over several years.
Some aspects can be considered in the prevention of cataracts, namely protection from ultraviolet light and from exposure to tobacco.
Cataract treatment is always surgical, although in the initial stages it is not recommended. In other words, surgery should be carried out when the loss of vision becomes important and symptoms significantly interfere with daily activities, such as reading and driving.
The current technique used for the removal of cataracts is phacoemulsification of the lens, resulting in a rapid visual recovery. It consists of a small incision in the eye (approximately 2mm) and fragmenting the lens, using an instrument called a phacoemulsifier that emits ultrasound through a titanium tip; the cataract is then aspirated. Subsequently, an intraocular lens is introduced, which does not cause astigmatism (blurred vision) or distortion of the cornea.
With this type of surgery, it is presently possible to correct high levels of refractive errors, namely astigmatism with more than 2 dioptres. In some cases, multifocal intraocular lenses are used, allowing the patient to obtain good visual acuity in distance, mid-distance and near.
Once the lens is in place, the surgery is considered to be complete, without the need for suturing, and the patient can resume normal activity in a few days.
To conclude, cataract is the leading cause of blindness and surgery is not just about restoring vision. It must be seen as a true refractive procedure as it is possible that after surgery the patient will be able to see well and with excellent optical quality.
Article supplied by the Hospital Particular do Algarve Group, with hospitals in Alvor and Gambelas (Faro)