Ophthalmology

Causes of cataract

Congenital cataracts

Causes of cataract formation

The causes of a cataract can, among other things, be a mutation at the gene level.

EphA2 is the name of the gene that contains the blueprint for an enzyme that can repair defective proteins in the lens of the eye. However, with advancing age, this gene produces smaller and smaller amounts of the repair enzyme, which causes the damaged proteins to clump together in the lens of the eye and these clumps then cloud the lens and then develop a cataract. This process also affects the refractive power of the eye and so visual acuity also suffers from the process of decreased protein repair.
With the help of a study, scientists were able to prove some mutations in the human EphA2 gene in patients with the form of cataracts, which is caused by age.
In further studies, the exact mechanisms that lead to cataracts are to be researched, which would make completely new therapeutic approaches possible.
What are the known causes of cataracts?

Old age (Senile cataracts): This is the most common form of cataract and a consequence of normal human aging. From around the age of 60, certain metabolic processes in the lens no longer function properly, which leads to clouding and swelling of the eye lens. However, there are considerable individual differences in this process and therefore also in the extent of the disease.
secondary cataracts (e.g. Diabetic cataracts): The best-known and most common metabolic disorder that leads to cataracts is diabetes (diabetes mellitus). This increases the sugar concentration in the eye water, as in the entire organism. The glucose (Sugar molecule) is then deposited on the lens, which causes the eye lens to swell and become cloudy due to water binding.
due to physical causes such as injuries and rays (X-rays, infrared and UV rays and electric current), bruising of the eyeball (punch, ball), stab wounds with damage to the lens, penetrating foreign bodies. The capsule of the eye lens is then injured, causing fluid to penetrate into the lens and cause it to swell (Traumatic cataracts).
Congenital Star (Cataract congenita): Certain hereditary diseases or rubella (40-60%) or mumps (10-20%) infection of the mother during pregnancy can cause congenital opacity of the eye lens in the child (Please refer: Infections in pregnancy)
Some skin diseases, such as neurodermatitis, or general diseases in which adequate kidney function is not fully guaranteed (dialysis required!), can lead to clouding of the lens and thus cataracts.
Drug-induced cataracts: with long-term systemic administration of cortisone, clouding of the lens is also observed as a side effect in some cases, just as with poisoning or malnutrition.

Hereditary causes

These arise from genetic inheritance of parents or grandparents. It was found that the cataract mostly autosomal dominant was passed on. This means that one burdened gene in the chromosome pair is enough to trigger the disease. As a rule one can expect that 50% of the offspring of a hereditary cataract sufferer cataracts will suffer.

A distinction can be made here between the Old agewhich by genetic Disposition in old age arises. However, development factors remain unknown. Old age cataract is the most common cataract. In 90% of the cases it is a star of old age. The old age is also called Kataracta senilis.
The star of old age has several causes. For one thing, there is one altered composition of the lens fluid, what the Clumping of proteins leads. In addition, there are oxidative changes caused by radicals, which the lens can damage and cloud. There are also osmotic causeswhich result from the conversion of sugar molecules into alcohol derivatives. As a result, more water in the lens remains.

Hereditary cataracts can also be called Concomitant illness another disease like Neurodermatitis and Wilson disease occur. Besides that, it also happens other hereditary diseases especially of the eyes, but also with other organ diseases, to cataracts. Even with one Galactosemia, a hereditary metabolic disorder with a special enzyme deficiency, cataracts can occur reversible is.

Hereditary cataracts can in children and adolescents occur which is normally atypical in classic old age cataracts and is accordingly rare.

Another risk factor for cataracts seems to be Down syndrome disease to be. Because about 50% trisomy 21 patients also suffers a cataract.

Internal and external causes

These include Irradiations for example through UV light or infrared light (e.g. with glassblowers) or radioactive radiation. Also can thermal (like by infrared light) or electromagnetic influences favor a cataract.

Also play alongside Smoke and high alcohol consumption a role. Also can Malnutrition Have an influence on it.

A cataract can also from other eye diseases like that glaucoma, severe myopia, Idriodocyclitis (an inflammation of iris and ciliary body), uveitis (inflammation of the middle skin of the eye). Besides that you can operative interventions on the eye or Injuries to the eyeball also cause a cataract. The eye injuries can be a Bruising of the eyeball or one Foreign body in the eyeball act. This shape is also called Traumatic cataracts.
The cataract from surgical interventions most often arises after Vitreous Removal with replacement by oil.

Also through diabetes (Diabetes), Hypothyroidism, Dialysis treatments and a cataract can develop if there is a lack of calcium. In diabetes, the cataract is caused by one increased sugar content in the eye water triggered. It comes to one Storage of the sugar in the lensresulting in an attraction of water. The lens begins to swell and the lens becomes cloudy. This special shape is called Diabetic cataracts.

Medication

In addition come Medicationwhich can trigger a cataract, like cortisone. Cataracts come about after many years of taking cortisone or medication containing cortisone. In cortisone-induced cataracts there is one Opacity of the posterior lens shell.

Congenital cataracts

This arises at Infections in pregnancy like through a Rubella- or Mumps infection. The congenital star can also be caused by a Hereditary disease be triggered. These include the diseases myotonic dystrophy, neurofibromatosis 2 and galactosemia. The congenital cataract is included under one percent of newborns in front.

Is the cataract already there? at birth or up to eighth week of life, it is one congenital cataract.

If a cataract occurs between the ninth week of life and the sixth year of life is it a juvenile cataract.