Causes of cataracts

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, as we 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, clouding the lens and causing cataracts to form. This process also affects the refractive power of the eye, so visual acuity also suffers from the process of reduced protein repair.

In one study, scientists were able to prove some mutations in the human EphA2 gene in patients with cataracts, a form of cataract that is caused by age. Further studies are planned to investigate the exact mechanisms leading to cataract disease, which would enable completely new therapeutic approaches. What are the known causes of cataracts?

  • Age-related cataract (cataracta senilis): This is the most common form of cataract and a consequence of normal human aging. From around the age of 60 onwards, certain metabolic processes of the lens no longer run properly, resulting in clouding and swelling of the lens. However, there are considerable individual differences in this process and therefore also in the extent of the disease.
  • Secondary cataract (e.g. cataracta diabetica): The best known and most common metabolic disorder leading to cataracts is diabetes mellitus.

    This increases the concentration of sugar in the water in the eye, as in the entire organism. The glucose (sugar molecule) then attaches itself to the lens, which causes the swelling of the eye lens due to water binding and thus leads to clouding.

  • Due to physical causes such as injuries and radiation (X-rays, infrared and UV rays) and electric current), bruising of the eyeball (punch, ball), stabbing injury with damage to the lens, penetrating foreign bodies. The capsule of the eye lens is then damaged, causing fluid to enter the lens and cause it to swell (cataracta traumatica).
  • Congenital cataract (cataracta congenita): Certain hereditary diseases or rubella (40-60%) or mumps (10-20%) infection of the mother during pregnancy can cause congenital clouding of the child’s eye lens (see: Infections during pregnancy)
  • Also some skin diseases, such as neurodermatitis, or general illnesses, in which sufficient kidney function is not completely guaranteed (dialysis obligation! ), can lead to clouding of the lens and thus to cataracts.
  • Drug-induced cataracts: in some cases, a clouding of the lens is also observed as a side effect of long-term systemic administration of cortisone, just as in cases of poisoning or malnutrition.