【Summary Description】 Cataract is a common visual impairment disease, which occurs in the crystalline lens of the eye. The crystalline lens, as an important component of the eye's refractive system, is similar to the lens of a camera. All light entering the eye needs to pass through the crystalline lens to reach the retina. When the crystalline lens undergoes protein denaturation and becomes cloudy due to various reasons, it can cause cataracts.

Cataract is a common visual impairment disease, which occurs in the crystalline lens of the eye. The crystalline lens, as an important component of the eye's refractive system, is similar to the lens of a camera. All light entering the eye needs to pass through the crystalline lens to reach the retina. When the crystalline lens undergoes protein denaturation and becomes cloudy due to various reasons, it can cause cataracts.

1、 Causes of Cataract

There are various causes of cataracts, mainly including the following:

1. Aging: As age increases, the metabolic function of the crystalline lens gradually decreases, making it prone to protein degeneration and opacity. Age related cataracts, also known as senile cataracts, are lens opacities that occur in middle-aged and elderly individuals. The incidence of cataracts in elderly patients over 80 years old is almost 90%.

2. Genetics: Genetic factors can also lead to the occurrence of cataracts, and people with a family history of inheritance have a relatively higher risk of developing the disease. Congenital cataract is a common blinding eye disease in children, with complex causes. It can be caused by genetic or maternal early pregnancy intrauterine viral infections, medication use, or the presence of certain metabolic diseases in the child.

3. Local nutritional disorders: Local nutritional disorders can interfere with the normal metabolism of the crystalline lens, leading to opacity.

4. Immune and metabolic abnormalities: for example, in patients with diabetes, the crystal osmotic pressure increases due to the increase of blood sugar, and the crystal becomes turbid after the protein absorbs water.

5. Trauma: including contusions, eye rupture injuries, etc. Trauma is also one of the important causes of cataracts.

6. Radiation: Long term exposure to harmful radioactive substances can cause lens opacity.

7. Poisoning: Certain systemic metabolic or immune diseases may also lead to cataracts.

8. Medications: Long term use of glucocorticoids, dilators, and other medications can also increase the risk of cataracts.

2、 Clinical manifestations of cataracts

The common clinical manifestations of cataract patients are:

1. Decreased vision: This is the most obvious and important symptom. When the lens opacity is significant, the patient's vision may decrease to only light perception.

2. Decreased contrast sensitivity: The ability to distinguish blurry objects decreases, and the contrast sensitivity at high spatial frequencies significantly decreases.

3. Refractive changes: may result in myopia, reducing pre-existing presbyopia; It may also lead to crystalline astigmatism.

4. Monocular diplopia or multi vision: seeing things produces double or multiple shadows.

5. Glare: When encountering strong light, there will be a dazzling and glaring feeling.

6. Color vision change: The sensitivity to certain light rays in the spectrum decreases, especially the ability to distinguish blue and green.

7. Visual field defect: It affects the patient's visual field to varying degrees.