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Health Centre
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Cataract
Introduction
Cause and Pathogenesis
Symptoms and Signs
Investigations and Diagnosis
Treatment and Prognosis
Prevention
Introduction
Cataract is a clouding or opacity of the lens in the eyes that leads to a gradual
loss of vision. It is one of the leading causes of blindness throughout
the world especially in elderly people. In the Asian sub-continent,
millions of people are affected by cataract.
Cause and Pathogenesis
Cataracts are associated primarily with ageing (senile cataracts) and changes
in the chemical composition of lens proteins. Injuries, toxins, systemic
disease, and intraocular inflammation can also cause cataract. Cataracts occurring
at birth (congenital cataracts), are rare, and are the result of inborn errors
of metabolism, exposure of a first-trimester foetus to rubella (german measles) or
toxins, and congenital anomalies.
Excessive exposure to ultra-violet light, and use of certain steroids might
also lead to the development of cataract. More than 60% of those over 65
years of age and 90% of those over age of 85 have opacities of the lens.
Symptoms and Signs
The main symptoms of cataract include progressive, painless blurring and
distortion of vision, glare from bright lights, and gradual loss of vision. Signs
include a gray or white colouring on the pupil and myopia may also occur.
Colour vision is also affected and objects may appear yellow. Halos or
coloured rings may form around bright lights.
Investigations and Diagnosis
The following tests can be done to assess the eyesight and detect the
development of cataract:
- Visual Acuity Test, to assess distant and near vision
- Refraction, to verify the strength of correction needed for best possible vision
- Slit-lamp Examination, to detect abnormalities in the cornea, iris and lens
- Tonometry, to check the intraocular pressure
- Ophthalmoscopy, to detect abnormalities of the retina and optic nerve
Treatment and Prognosis
Surgery is the main treatment for cataract and produces the best results. Intracapsular or extracapsular removal of the lens can be performed and later, follow-up laser surgery to remove secondary membranes can be performed. Phaco-
emulsification can be done. After the cataract is removed, intra-ocular lens (implanted at the same time as the lens is removed), contact lenses or glasses can be used to correct the refractive errors. After correction of the refractive errors, the patient will be able to regain good eyesight and perform most of the normal activities.
Prevention
Cataract is mainly a disease that occurs in the elderly people and tends to develop as the age increases. However, proper care of the eyes and control of the causative factors like injuries to the eyes, diabetes and hypertension can prevent the cataracts that develop due to these causes.
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