What is a cataract and why is it created? Causes and risk factors - Dr. Mohammad Periman
Dr. Mohammad Periman
TabrizSurgeon and ophthalmologist
Cataract is one of the most common eye diseases worldwide, which is mostly seen in old age. In this disease, the clear lens of the eye, which is responsible for focusing light on the retina, gradually becomes cloudy and the person's vision decreases. Although in the early stages, a person may only feel a slight blur in his vision, over time, cataracts can lead to significant blindness. In this article, we comprehensively explain what cataracts are, how they form, what factors cause them, and how to prevent them.
Table of Contents
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The lens of the eye is a clear and flexible structure that sits behind the iris (the colored part of the eye) and helps focus light on the retina. This disease occurs when the proteins in the lens change their structure and accumulate in the form of masses. This accumulation causes the light to not pass through the lens properly, and as a result, the image on the retina is blurred or opaque. In simple words, cataract means clouding of the lens of the eye. This turbidity can occur in a small part of the lens or in its entirety. As the intensity of turbidity increases, the person's vision becomes more disturbed. There are different types of cataracts, which are divided based on the location of the turbidity in the lens: This type develops in the center of the lens (nucleus) and is usually seen with age. At first, it may temporarily improve near vision, but vision will gradually decrease, especially in low light. In this case, a cloudiness starts from the outer layers of the lens and moves towards the center. Patients often complain of glare in the light and difficulty seeing when driving at night. This type is created in the back part of the lens and close to its capsule. It usually progresses more quickly than other types and is more common in people with diabetes or those taking corticosteroids. In this case, turbidity develops in the front part of the lens, just below the anterior (front) capsule. Its cause is usually damage or eye inflammation, but it can also result from reaction to certain drugs or impact. The symptoms are similar to other types, but may be associated with eye inflammation. Some babies may be born with cataracts or develop them in the early years of life. Its causes are usually genetic, infections during pregnancy or metabolic problems. As a result of a direct blow to the eye, penetration of a foreign body or surgical injury, the structure of the lens may be destroyed and a cataract may be created. This type may appear immediately after the injury or years later. Depending on the type and severity of the impact, the appearance of cataracts is different. This type occurs after other diseases or drug treatments. For example, diabetic patients or people who take corticosteroid drugs for a long time are more susceptible to it. Also, after eye surgeries such as cataract or retina surgery, secondary opacity may develop in the capsule behind the artificial lens, which is also called Posterior Capsule Opacification. This condition is usually treated with laser. This type is caused by long-term exposure to ionizing radiation or ultraviolet radiation. People who deal with radiation sources in industrial, laboratory, or medical settings (such as radiologists and radiology technicians) are at greater risk. In patients with uncontrolled diabetes, high sugar can cause the accumulation of sorbitol in the lens. This accumulation causes water absorption, changing the structure of lens proteins and resulting in turbidity. This type usually appears at a younger age than other types and can affect both eyes. Cataract, like other diseases, has stages of development. In each stage, the lens of the eye is worn in different sizes
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The exact cause of cataracts is not known in all cases, but in general, a combination of natural aging processes and environmental factors play a role in its creation. In old age, the structure of lens proteins undergo oxidative changes and as a result, the lens loses its transparency. However, several factors can speed up this process. The most common cause of this disease is aging. Almost everyone over the age of 60 experiences some degree of lens opacities, although they may not need treatment. Ultraviolet (UV) rays in sunlight can gradually damage lens proteins. People who spend a lot of time outdoors without proper sunglasses are more at risk. High blood sugar changes the composition of the liquid inside the lens and accelerates its clouding process. Diabetic patients should have more accurate control of their blood sugar to reduce the risk of cataracts. Steroid drugs, especially in chronic use or high doses, can cause posterior subcapsular cataracts. Smoking and constant alcohol consumption both increase free radicals in the body, which accelerates the destruction of lens cells. Injury to the eye or performing surgeries such as retinal surgery can cause changes in the structure of the lens and increase the possibility of contracting this eye disease. If one family member has cataracts, the probability of its occurrence in other family members is also higher. The role of genetics in some types of congenital cataracts has also been well proven. Nutritional deficiency, obesity, high blood pressure, and exposure to certain chemicals can also play a precipitating role.What is cataract
?
Cataract types
1. Nuclear pearl water
2. Cortical cataract
3. Posterior subcapsular cataract
4. Anterior Subcapsular Cataract
5. Congenital pearl water
6. Traumatic Cataract
7. Secondary Cataract
8. Radiation Cataract
9. Diabetic Cataract
Stages of eye cataract development
Stages of Cataract Development - Photo of water the pearl
1. Immature Cataract (immature or mild cataract)
2. Mature Cataract
3. Hypermature Cataract (overmature or old)
What is the cause of cataract
?
Risk and underlying factors
Old age
exposure to sunlight
Diabetes
Long-term use of corticosteroids
Cigarettes and alcohol
Previous eye injury or surgery
Family history
Other factors
