A cataract is a painless, cloudy area in the lens of your eye. A cataract blocks light from reaching the retina (the nerve layer at the back of the eye) and may cause vision problems.
Cataracts are common in older adults and are linked to aging. Smoking and exposure to too much sunlight are other risk factors. Cataracts can also happen after an eye injury, as a result of eye disease, after you use certain medicines, or as a result of health problems such as diabetes.
What causes cataracts?
- A cataract occurs when the lens inside your eye gets cloudy. Things linked to clouding include:
- Aging. But changes caused by aging don't always lead to cataracts.
- Overexposure to ultraviolet (UV) radiation. This includes UV light from sunlight, tanning booths, or sun lamps.
- Diabetes, especially when the blood sugar levels are above the safe range. This can cause changes in the eye that can cause cataracts.
- Diseases inside the eye. These include glaucoma, retinitis pigmentosa, retinal detachment, and long-term uveitis.
- Long-term use of steroid medicines.
- Frequent X-rays or radiation treatments to the head.
- Family history. A person may inherit the tendency to get cataracts.
- Vitrectomy. People who have had the vitreous gel removed from their eye (vitrectomy) have a higher risk of cataracts.
- Eye injury. Injury-related cataracts are rare. But injury is a leading cause of cataracts in children.
- Being born with cataracts (congenital). Some children are born with them.
What are the symptoms of cataracts?
Cataracts can affect your vision in several ways.
- You may have cloudy, fuzzy, or foggy vision.
- You may see glare from lamps or the sun. You may have trouble driving at night because of glare from car headlights.
- You may need to change your eyeglasses prescription often.
- Your near vision may improve for a short time if you get a cataract. This temporary improvement is called second sight.
The vision loss from a cataract often happens slowly. It may never become severe. Many times, cataracts don't cause any vision problems.