Cataract is the most common cause of decreased vision in the world. As we mentioned in eye anatomy, light passes through the transparent layers of the eye while passing through the external environment. For the image to be formed, the light must first pass through the front transparent layer of the eye, which we call the cornea. This light then passes through the lens in the eye, another transparent tissue, and reaches the retina. The lens is a transparent and curved structure on both sides. It ensures that the light coming into the eye is refracted and the image is focused on the vitreous cortex.
The lens must be transparent for life, if it loses its transparency at any time, this condition is called a cataract. It creates difficulties for the person to see by decreasing the contrast and causing problems for light to reach the retina.
The lens in the eye loses its transparency and takes on the icy glass structure. Just as a person sees the image as hazy when he looks through icy glass, the image seen by a person with cataract becomes the same as hazy, icy and misty.
In advanced stages, a mature cataract can reduce the image of a person only to a level where he/she can only notice the light. The person looking at the person with such a advanced cataract may notice a white image instead of black on the pupil.
What is the cause of Cataracts?
There are many reasons for the lens in our eyes to lose its transparency. The most important of all is the increasing age. With the increasing age, the water content of the lens decreases and the amount of lens proteins increases. In this case, the lens hardens, its flexibility decreases, and as a result, the transparency of the lens decreases gradually.
Another important reason is sun rays exposed with increasing age. The eye, which is exposed to ultraviolet, that is, ultraviolet rays of the sun without wearing sunglasses, actually turns its lens from transparent state to icy glass state as a defence mechanism, so that no more damaging light reaches the retina. This is because these harmful rays coming to the retina cause macular degeneration, which we will explain later.
One of the causes of cataracts is trauma. With a blunt or pointed object striking the eye from the outside, the lens inside the eye may lose its transparency by changing its place, or it may lose its transparency in its location by not changing its place. The use of drugs with cortisone can be considered as one of the more rare reasons that can lead to cataract. When cortisone medication is used in the form of drops, it causes cataract as well as it can lead to cataract formation and when used orally in the form of pills.
Hereditary metabolic diseases cause congenital cataract in new-born babies, while in adults, many systemic diseases such as diabetes and thyroid disease can cause cataract. From systemic diseases, especially in diabetes, if the blood glucose level is kept within normal limits, the development of cataracts slows down.