March 10, 2022First Posted: September 21, 2021
Last Updated: March 10, 2022
| Basecamp, Cataracts

Your Comprehensive Handbook To Learn What Are Cataracts

By Barrett Eubanks, M.D.

Your Comprehensive Handbook To Learn What Are Cataracts

At some point in everyone’s life, vision begins to decline due to cataracts. It’s not anything to worry about or be afraid of. If you live long enough, you will end up with cataracts at some point. Often in your retirement years but sometimes even before that when you are younger.

But what exactly is a cataract?

Everyone has a lens inside their eye that is involved in focusing vision. Over time this lens gradually becomes cloudy. Eventually this cloudiness makes it harder to see and enjoy your normal activities. At this point, this lens is now called a cataract.

Cataracts have a wide variety of symptoms. Often symptoms are very gradual and many people do not notice the deterioration of their vision until it has affected them quite a bit. But fortunately cataracts are readily diagnosed with a full exam with your eye doctor and are easily and safely treated with cataract surgery.

Cataracts Come The Natural Lens Inside Your Eye

Everyone has a natural lens inside their eye. Like lenses you would have in a glasses prescription, your natural lens is involved in focusing light in the eye.

You may not even know that you have this lens because you can't really see it. This lens sits behind the iris or colored part of our eye. When you look at someone's pupil, you are looking through this lens. But because this lens is clear and transparent, you can't see this lens without using a microscope found in an eye doctor's office.

The lens
The lens; image by File:Three Internal chambers of the Eye.png: Artwork by Holly Fischer derivative work: Pixelsquid, CC BY 3.0, via Wikimedia Commons / cropped from original

But this lens doesn't remain clear and transparent forever. Over time, this lens becomes cloudy. When this cloudiness causes you to lose vision, this lens is called a cataract. A cataract is simply a cloudy lens inside your eye.

Fun history lesson! The word cataract actually comes from the latin word “cataracta" which means waterfall. When cataracts get very dense, they can assume a white coloration which can look like a waterfall within the eye! But when cataracts aren’t quite as dense as a waterfall, there can be little change in the outward appearance of the eye.

Dense "waterfall" type cataract
Dense "waterfall" type cataract; image by Imrankabirhossain, CC BY-SA 4.0, via Wikimedia Commons

What You Notice With Cataracts

Cataracts cause a variety of symptoms. Any of these can be a clue that cataracts are developing within your eyes:

  • Blurry vision
  • Glare or difficulty with night vision
  • Trouble with in low light or poor contrast situations
  • Change in color perception
  • Change in prescription
  • Double Vision

The most common symptom of cataracts is blurry vision. Blurry vision is caused by the light from an object not being focused at the same spot on the retina. As light hits this lens, the cloudiness causes the light to scatter. Thus, things become blurry. As the cataract gets worse, this happens more and more and makes it more challenging to see.

But in addition to causing blurry vision, this scatter of light can be even worse at nighttime with certain types of cataracts. When light shines in the eye, this can cause so much blurriness that it becomes difficult to see anything. As this happens more at nighttime, this dramatically effects the ability to drive at night. Glare from the headlights of oncoming cars can make it difficult to see anything.

In addition to blurry vision and glare, the contrast in your vision starts to decrease. This further degrades your ability to see things clearly. If you walk indoors wearing sunglasses, everything is dark and difficult to see. The sunglasses block light from reaching your eyes. So, of course, you take the sunglasses off. Cataracts cause the same thing. The cloudiness from a cataract blocks light from reaching the back of the eye. This reduces contrast and again makes things more difficult to see.

There are sometimes subtle symptoms that can be more difficult to notice. One is a change in how you see different colors. The cloudiness from the most common type of cataract develops a yellow-brown appearance. This appearance causes everything you see to have a yellow-brown tint. The trouble is, because both eyes are commonly affected, there is no reference to what colors should actually look like. It is typically only noticed after cataract surgery when the cataract is replaced with a clear lens; everything looks very vivid with more blues and purples.

Cataracts can also cause a change in the prescription for some individuals. In particular, a cataract can cause you to become more nearsighted; and often dramatically so! For someone who doesn’t need any glasses except to read, this change in prescription can actually give the ability to see up close again (although with some blurriness from the cataract). This phenomena is thus occasionally called “second sight".

Lastly, and also less common, cataracts can cause some double vision. This double vision will cause a shadowing effect. Unlike other causes of double vision, it won't go away when closing one eye.

It Can Be Difficult to Recognize The Symptoms

Despite all the symptoms that cataracts cause, sometimes you can have difficulty even noticing these symptoms. This is because cataracts often develop very slowly. You may not even realize you are losing vision. But gradually over time, tasks become more difficult.

What activities are impaired by cataracts (even with glasses)?

  • Reading books
  • Watching television or movies
  • Filling out paperwork
  • Reading labels on food products or medicine bottles
  • Quickly recognizing obstacles such as curbs and steps
  • Reading traffic or street signs
  • Performing fine activities such as sewing or woodwork
  • Playing board or card games

When you start to notice some trouble, it is time to visit your eye doctor for a full eye examination to evaluate for cataracts.

How Cataracts Are Diagnosed

Cataracts can be diagnosed by an optometrist or ophthalmologist during a full complete dilated eye exam. (see also How Often Should You Go To The Eye Doctor?)

At this exam, your visual acuity is measured (what you can read on an eye chart) to check for any blurry vision. Vision may also be measured while light is shining in your eye to evaluate for any significant glare. These can determine if there is any noticeable impact to your vision.

But the cataracts themselves are seen very readily at the microscope in the office. When the eye is dilated, the eye doctor has a clear view of the lens and can see if there is anything cloudy forming in the lens and causing a cataract.

The remainder of the eye exam ensures that the rest of the eyes are healthy and that it is the cataracts causing the trouble.

Slit-lamp microscope to examine for cataracts
Slit-lamp microscope to examine for cataracts; image by OKJaguar, CC BY-SA 4.0, via Wikimedia Commons

Where Do Cataracts Come From?

The vast majority of cataracts don’t have a single cause. They just happen. Gradually over time.

But there are certain things which will increase the risks of cataracts.

  • Age
  • Family history of early cataracts
  • Smoking
  • UV light

Aside from stopping smoking and wearing sunglasses, there isn’t much you can do to prevent cataracts from occurring.

But there are certain types of cataracts which do have a known cause. Eye injuries, radiation treatments, diabetes and any steroid use (ANY type of steroid: steroid pills, steroid injections and even steroid nasal sprays!) are known common causes of cataracts.

These cataracts with known causes are somewhat preventable. By protecting your eyes in dangerous settings, you can avoid eye trauma. By keeping the blood sugars under control with diabetes, you can prevent cataracts from developing. By using steroids sparingly as advised by your doctor, you can prevent the steroids from causing cataracts. But sometimes despite your best effort, you will still get cataracts.

Who Gets Them?

Anyone can get cataracts. Sometimes cataracts just happen no good rhyme or reason.

Cataracts can develop anytime from birth all the way on to the golden years. But fortunately, cataracts are rare when you are young.

The most common type of cataract starts to form later in life. The first signs of symptoms from cataract may be noticed in the late fifties or early sixties. As the years continue, the cataracts become worse and start to affect daily life more and more.

During these years, it is a good idea to have regular follow-up with your eye doctor once a year to make sure you don’t have to struggle with vision impairment from cataracts.

Because the good news is that cataracts have a safe and easy fix!

Cataracts Are Fixed With Cataract Surgery

To restore sight and correct vision, cataracts are removed through cataract surgery. This applies to any type and any cause of the cataracts.

Cataract surgery has become highly refined over the years. It has become a simple and safe outpatient procedure. The surgery takes about 15-20 minutes and the recovery is almost as quick. Within a day or two after cataract surgery you are already seeing clearer.

During cataract surgery, the cataract is broken up with ultrasound energy and frequently also lasers and then removed with a microscopic vacuum. This process is very precise and safe. Following removal of the cataract, a new artificial lens is placed within the eye. This lens is completely clear and often is used to correct your prescription after cataract surgery to sharpen up vision without glasses.

There isn’t any major downtime after cataract surgery. For the first few weeks, you simply want to limit heavy lifting or strenuous activity, bending over or getting water in the eyes.

Vision loss from cataracts is able to be restored that easily.


Cataracts are a part of life for everyone, it’s just a question of when. For most people, cataracts will occur at an older age, but not always: some younger individuals will get cataracts. When cataracts occur, one can experience a wide variety of symptoms, but most frequently will have some degree of blurred vision. But regardless of the cause, cataracts can be corrected very effectively through cataract surgery.

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