What is The Cause of Cataract in The Eye?
Before knowing the cause, cataract needs to be divided on the basis of causes that are whether it is congenital or sporadic? So what is the etiology behind the cataract?
- Congenital Cataract – This type of cataract occurs at birth.
- Acquired Cataract-
Types of acquired cataract and its causes include-
Senile Cataract- which occurs with the declining age and this is the most common type of cataract in India. Increased opacity of lens fibers is the main etiological factor, which occurs due to water accumulation and protein coagulation within the lens fibers.
Traumatic Cataract – It occurs due to injury from any substance.
Complicated Cataract – It occurs as a complication of any other diseases or in association with another disease.
Metabolic cataract this is most commonly seen in a patient with diabetes and the classical picture is of snowstorm type appearance.
Electric Cataract- this occurs when exposed to the electric current of high voltage.
Radiations Cataract- usually due to UV rays which is most abundant in sun rays that is why it is recommended to wear sunglasses in hot summer months.
Toxic cataract which includes corticosteroid induced cataract, miotics induced, copper-induced cataract and lastly iron-induced cataract. The substances like iron and copper get deposited in the lens and impart color to the lens. Deposition of iron is seen in hemosiderosis and deposition of copper is usually seen in Wilson’s disease. These deposits impart a classical color to the lens.
Cataract may occur in association with other diseases like skin diseases. There are few syndromes where we can see such classical presentation.
Cataract associated with issues of disease.
Cataract can even occur with other diseases which include Lowe’s syndrome, congenital rubella syndrome, Down syndrome and the most of them presents with a classical triad of symptoms.
This was all about the etiological causes of the cataract but besides etiological causes, there are few morphological causes as well which include cortical, capsular and subcapsular cataract and so on.
So now what is the main cause of senile cataract which is usually the most commonly encountered cataract in Indian hospital setting? So here are few main causes-
Smoking is considered as an important cause as it causes coagulation of protein and accumulation of certain products which initiate the process of opacification all these leads to disruption of the function of Na/K pump and thus accumulation of fluid inside the cell. So, any toxic substance can cause disruption of this pump along with coagulation of proteins which are considered main in the process of opacification.
Other Factors Which Increase The Chance of Cataract Include-
Congenital Cataract May Occur Because of Following Etiological Factors-
- These include malnutrition that is an inappropriate intake of nutrition at the time of gestation. Infections include infection of Toxoplasma and cytomegalovirus. If a woman is exposed to such infection she should opt for screening prior to delivery.
- Drugs which are considered main cause of cataract in children and among them corticosteroid tops the list and are a major cause of drug-induced cataract. Besides this, there was a drug named thalidomide which was used a decade back but due to its side effect and teratogenic potential, its use has been stopped.
- Radiation is another cause that is why it is recommended to do less number of X- rays in pregnancy until and unless women are suffering from such ailments which necessitate the use of X-rays so only critical ailments are the indications to do an X-ray in females.
Inappropriate oxygenation is an important cause. This may induce cataract.
- Metabolic disorders which include galactosemia, glucokinase deficiency and hypoglycemia. These disorders can cause cataract and these are given specific names like galactose induced cataract gives oil drop appearance.
- Another cause is birth trauma which may initiate cataract in a young one.
- Malnutrition is another important cause, especially deficiency of selenium and vitamin E is held responsible for the development of cataract.
Cataract may be associated with other congenital anomalies such as Lowe’s syndrome. In diabetic mother chances of development of prematurity of retinopathy. Thus all these lead to the development of cataract.
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