To diagnose cataracts, a doctor will typically perform a comprehensive eye examination, including a visual acuity test and a slit-lamp examination.

A cataract is a cloudy area in the lens of the eye, which is the clear part inside of the eye that helps to focus light. Symptoms that might lead to a cataract diagnosis include blurry vision, double vision, and reduced night vision.

This article explores how doctors diagnose cataracts in more detail. It also covers risk factors for cataracts, symptoms, and treatment options.

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If a person has concerns about cataracts, they may wish to contact an eye doctor, or optometrist. The doctor will typically perform a comprehensive eye assessment to diagnose cataracts.

The eye exam may include a series of different tests.

Visual acuity test

A visual acuity test is an eye examination that examines how well a person sees. A common visual acuity test is the Snellen test.

During the Snellen test, a person will read letters or numbers from a distance while covering one eye.

If a person cannot do a Snellen test, the eye doctor may use another test.

Pupillary response

During a pupillary response test, the doctor will examine the cornea, iris, lens, and other structures in the eye to check for signs of cataracts.

Tonometry test

Tonometry is a diagnostic test that measures the pressure inside the eye, or intraocular pressure. The doctor will use a tonometer to measure the pressure of the fluid in the eye.

The doctor will carry out this examination to rule out any underlying cause due to abnormal pressure in the eyes, such as glaucoma.

Slit lamp examination

The doctor may examine the eyes using a slit lamp, which is a microscope with a bright light.

During this exam, the doctor will apply a special dye. This will give them a good view of the structures in the eye.

A person may experience sensitivity to light for a few hours after this exam. They should not drive immediately afterward.

Learn more about slit lamp exams.

A cataract is a progressive condition. The National Eye Institute notes that a person with cataracts may notice the following symptoms over time:

Learn about the early signs of cataracts.

According to the American Optometric Association, the level of visual impairment will determine the type of treatment a doctor will recommend for cataracts.

Home treatment

Early on, a doctor may recommend the following home remedies to manage cataracts:

  • using brighter lights at home and work
  • using a magnifying glass for reading
  • wearing antiglare glasses or sunglasses
  • having an eyesight test to determine whether a new prescription will help

New prescription glasses or contact lenses

In some cases, changing the eyeglass prescription may provide temporary vision improvement. For some people, getting a new eyeglass prescription may help them see better.

The doctor will examine a person’s symptoms and eye structure to recommend the right prescription.


The doctor may recommend surgery as a last resort if cataracts negatively affect a person’s daily activities and quality of life.

During cataract surgery, an ophthalmologist removes the clouded lens and replaces it with a new, artificial lens called an intraocular lens. Cataract surgery is generally very safe, and 9 out of 10 people who get it have improved vision afterward. This translates to a 90% success rate.

Learn more about cataract surgery.

People may have a higher risk of cataracts if they:

There are no treatments that slow down or help prevent the progression of cataracts following a diagnosis. Medical experts advise that adhering to certain preventive strategies may help. These include:

Here are answers to some frequently asked questions about cataracts.

How can a person know when cataracts need treatment?

When a cataract progresses to the point that it affects a person’s ability to perform everyday tasks, a doctor will most likely recommend surgery.

How is a person’s vision with cataracts?

People with cataracts can experience cloudy or blurry vision. In some cases, a person may also see a shadow or have double vision.

What diagnostic tests happen before cataract surgery?

Before cataract surgery, a doctor will perform some diagnostic tests as a part of a comprehensive eye exam. This may include a visual acuity test, slit lamp exam, and pupillary response test.

Cataracts are a cloudy area in the lens of the eye. The doctor may diagnose cataracts and rule out other possible causes using a visual acuity test, slit lamp exam, and pupillary response test, which are all part of a comprehensive eye examination.

While the level of visual impairment will determine treatment, it may include wearing prescription glasses, trying home remedies, and having surgery.