What is a Cataract?

Many are surprised when their eye doctor first tells them they have a cataract and the natural questions is, what is a Cataract?


The lens inside your eye helps focus images for your vision. When you are born your lens is totally clear. However, time causes your lens to yellow, which robs clarity. Eventually, in your senior years, the lens becomes so yellow and blurry we call it a cataract.


When it starts to affect the course of your life, it is probably time to consider cataract correction. Cataract surgery is the most commonly performed surgery in the world because it is one of the most successful. Everyone blessed with long life will eventually need to have cataract correction so you are not alone.  For this reason, the questions isn’t so much “what is a cataract?,” but “when is my cataract ready to be removed?”

Cataract Symptoms

One answer to the question, what is a cataract, is that a cataract is a lens that causes glare and blurry vision. A cloudy lens causes light to scatter. This causes glare with oncoming headlights at night and blurry vision.

Eye Surgery Procedure

Another answer to the question, what is a cataract, is that a cataract is a lens so cloudy that it needs to be removed so you can see better. Cataract surgery involves removing the cloudy cataract lens through very small incisions and replacing it with a small plastic implant called an intraocular lens.


If the cloudy cataract lens is the only problem with your vision, then you would likely have a quick return to normal visual clarity. Imagine how rewarding it is for an eye surgeon to see patients regain their vision every single week!

Lens Implant

The lens implant, also called an intraocular lens, comes in a wide array of powers. Measurements are performed on your eye prior to surgery to help the surgeon know which lens implant power would give you the best vision after surgery. Laser measurements tend to be more accurate than ultrasound for this part of the process.


The good news about cataract surgery is that we can fix not only the cloudy cataract lens, but we can also choose a intraocular lens power to try to reduce your need for glasses. We work hard to find the right lens implant power for you to minimize your dependence on glasses. If you have worn thick glasses your entire life, consider what it would be like if after surgery you hardly needed them to see the clock in the morning! It is truly one of the modern miracles in medicine.


The news gets even better about cataract surgery because we now have advanced technology lens implants that can reduce or eliminate astigmatism and others that can reduce or eliminate the need for reading glasses (presbyopia). Let’s talk about both of those individually.


Astigmatism means that the eye is shaped more like an egg than a round ball. The irregular shape of an eye with astigmatism causes images to be out of focus for both distance and near vision. A toric lens is an advanced technology lens that corrects astigmatism and improves focus.


Presbyopia means “old vision.” When you are young, you can focus on both distance and near objects without glasses because the lens inside your eye can change shape and focus. As you age, the lens loses its flexibility and can no longer change shape and focus so you need reading glasses. Advanced technology lenses like the ReSTOR, Technis Multifocal, and Crystalens give many patients both distance and reading vision without the need for glasses. Freedom!


There are two ways to remove the cataract–manual or femtosecond laser. Manual cataract surgery is more hands on. It involves the eye surgeon looking through a microscope to judge anatomy and then using steel knives and instruments to make the incisions, open up the lens capsule, and divide the lens into small pieces.

Femtosecond Laser

In femtosecond laser cataract surgery, a 3D image is presented to the surgeon on a screen. The surgeon designs the incisions on the screen and then the laser with all its precision makes the incisions, opens the lens capsule, divides the lens into small pieces and even reshapes the cornea to decrease astigmatism. Many patients prefer the precision of laser cataract surgery.


I hope this overview helps you answer the question, what is a cataract, and aids you in your quest for better vision. Please feel free to contact me if you have further questions.

Gary J.L. Foster, MD