Cataracts

What happens in a cataract

The lens is made mainly of water and precisely arranged proteins that keep it clear. With age and other stresses, these proteins clump together and the lens yellows and hardens. Light scatters instead of focusing sharply, so images become blurred, dim and glary. Cataracts usually develop slowly over years and often affect both eyes, one more than the other.

Symptoms of cataracts

• cloudy, blurry, hazy or dim vision
• glare and halos around lights, especially headlights at night
• poor vision in dim light and trouble driving at night
• colors looking faded, brownish or yellowed
• needing brighter light to read
• frequent changes in glasses prescription
• double vision in one eye
• a temporary improvement in near vision in older adults ("second sight") as a nuclear cataract changes focus

Cataracts do not cause pain, redness or itching.

Types of cataracts

Causes and risk factors

• Age: the main cause; changes often begin in the 40s and 50s but usually affect vision after 60.
• Diabetes: cataracts develop earlier and faster.
• Smoking and heavy alcohol use.
• Ultraviolet light exposure over years.
• Long-term steroid use, including tablets, inhalers at high doses and eye drops.
• Eye injury or previous eye surgery.
• Eye inflammation such as uveitis.
• High myopia, family history, radiation exposure and some inherited conditions (myotonic dystrophy, galactosemia).
• In babies: infections in pregnancy (such as rubella), genetic conditions and metabolic disorders. See congenital cataracts.

Diagnosis

An optometrist or ophthalmologist will:

1. Measure visual acuity with a letter chart.
2. Test glare sensitivity in some cases.
3. Examine the lens with a slit-lamp microscope after dilating the pupil.
4. Examine the retina and optic nerve to check for other causes of vision loss, such as macular degeneration, glaucoma or diabetic retinopathy, which affect how much surgery can help.
5. Before surgery, measure the length and curvature of the eye (biometry) to choose the right artificial lens.

Treatment

Early cataracts

• an updated glasses prescription
• brighter, well-directed lighting for reading
• anti-glare sunglasses and a hat outdoors
• magnifiers
• avoiding night driving if glare is a problem

No eye drops or supplements have been proven to reverse or dissolve cataracts.

When to have surgery

Surgery is recommended when the cataract interferes with activities that matter to you, such as driving, reading or working, or when it prevents treatment of other eye conditions. There is no need to wait until a cataract is "ripe". In many places, minimum vision standards for driving also guide timing.

Cataract surgery

• The procedure: usually done as day surgery under local anesthetic eye drops and light sedation. The surgeon makes a tiny incision, breaks up the cloudy lens with ultrasound (phacoemulsification) and removes it, then inserts a clear plastic intraocular lens (IOL). It takes about 15 to 30 minutes per eye.
• One eye at a time: usually a few weeks apart, though same-day surgery on both eyes is offered in some settings.
• Lens choices: - Monofocal: clear vision at one distance, usually far, with reading glasses for near. - Toric: corrects astigmatism. - Multifocal or extended depth of focus: reduce dependence on glasses, but may cause more halos. - Monovision: one eye set for distance, the other for near.

Recovery

• Vision often improves within a few days and stabilizes within about 4 to 6 weeks.
• Use prescribed antibiotic and anti-inflammatory eye drops for several weeks.
• Wear an eye shield at night for the first week, and avoid rubbing the eye, swimming and heavy lifting for 1 to 2 weeks.
• Get new glasses once the eye has settled, usually after a month.

Risks

Cataract surgery is among the safest operations, with good outcomes in about 9 in 10 people or more. Possible complications include:

• Posterior capsule opacification: the lens capsule behind the implant clouds over months or years, causing blurred vision again. It is common and treated with a quick, painless YAG laser in the clinic.
• infection inside the eye (endophthalmitis), which is rare but serious
• swelling of the cornea or retina (macular edema)
• retinal detachment
• raised eye pressure
• dislocation of the lens implant

Cataracts in children

Babies born with cataracts need prompt treatment, often surgery in the first weeks to months of life, followed by glasses or contact lenses and patching. Without treatment, the brain does not learn to see properly through that eye (amblyopia). A white pupil in photos needs urgent assessment, partly to exclude retinoblastoma.

Prevention

You cannot prevent age-related cataracts entirely, but you can slow them:

• Wear UV-blocking sunglasses and a brimmed hat.
• Do not smoke.
• Control blood sugar if you have diabetes.
• Limit alcohol.
• Use steroids only as prescribed, at the lowest effective dose.
• Wear protective eyewear for risky activities.
• Have regular eye exams.

Frequently asked questions

What are the early signs of cataracts?

Early signs include slightly blurry or hazy vision, glare from bright lights and headlights, halos around lights, needing more light to read, faded colors and frequent changes in your glasses prescription. Symptoms usually develop slowly over months to years.

When is the right time for cataract surgery?

The right time is when the cataract affects your daily life, for example driving, reading, hobbies or work, or when it stops your eye doctor treating another eye condition. There is no benefit in waiting for a cataract to become "ripe".

How long does cataract surgery take to heal?

Most people notice better vision within a few days. Full healing takes about 4 to 6 weeks, after which new glasses can be prescribed if needed. You can usually return to light activities within a day or two and to most normal activities within a week.

Can cataracts come back after surgery?

The cataract itself cannot return, because the natural lens is removed. However, the thin capsule that holds the new lens can become cloudy months or years later. This is treated with a quick, painless laser procedure in the clinic.

Can cataracts be treated without surgery?

No medicine, eye drop or supplement has been proven to remove cataracts. Early on, stronger glasses, better lighting and anti-glare lenses help you see more comfortably. Once a cataract limits your daily life, surgery is the only effective treatment.