What is Cataracts?
A cataract is a clouding of the eye’s natural lens, which lies behind the iris and the pupil.
Cataracts are the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world.
Types of cataracts include:
- A subcapsular cataract occurs at the back of the lens. People with diabetes or those taking high doses of steroid medications have a greater risk of developing a subcapsular cataract.
- A nuclear cataract forms deep in the central zone (nucleus) of the lens. Nuclear cataracts usually are associated with aging.
- A cortical cataract is characterized by white, wedge-like opacities that start in the periphery of the lens and work their way to the center in a spoke-like fashion. This type of cataract occurs in the lens cortex, which is the part of the lens that surrounds the central nucleus.
What Causes Cataracts?
The lens inside the eye works much like a camera lens, focusing light onto the retina for clear vision. It also adjusts the eye’s focus, letting us see things clearly both up close and far away.
The lens is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it.
But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract, and over time, it may grow larger and cloud more of the lens, making it harder to see.
No one knows for sure why the eye’s lens changes as we age, forming cataracts. But researchers worldwide have identified factors that may cause cataracts or are associated with cataract development.
Besides advancing age, cataract risk factors include:
- Ultraviolet radiation from sunlight and other sources
- Prolonged use of corticosteroid medications
- Statin medicines used to reduce cholesterol
- Previous eye injury or inflammation
- Previous eye surgery
- Hormone replacement therapy
- Significant alcohol consumption
- High myopia
- Family history
One theory of cataract formation that’s gaining favor is that many cataracts are caused by oxidative changes in the human lens. This is supported by nutrition studies that show fruits and vegetables high in antioxidants may help prevent certain types of cataracts
When symptoms begin to appear, you may be able to improve your vision for a while using new glasses, strong bifocals, magnification, appropriate lighting or other visual aids.
Think about surgery when your cataracts have progressed enough to seriously impair your vision and affect your daily life.
Many people consider poor vision an inevitable fact of aging, but cataract surgery is a simple, relatively painless procedure to regain vision.
Cataract surgery is very successful in restoring vision. In fact, it is the most frequently performed surgery in the world.
Nine out of 10 people who have cataract surgery regain very good vision, somewhere between 20/20 and 20/40.
During surgery, the surgeon will remove your clouded lens and in most cases replace it with a clear, plastic intraocular lens (IOL).
There are 3 type of lenses:
Monofocal: A monofocal lens is a type of intraocular lens. While multifocal lenses focus on various distances, monofocal lenses focus on a single distance. You can choose between near, intermediate, and far distances when selecting these lenses. You can also get one distance in one eye and one in the other. It will be like walking around with bifocals inside of your eyes.
Bifocal: The patient sees both close and far away without glasses, but the distance between 40 cm and 2 meters called the middle distance is not visible.
Multifocal ( Trifocal ): Multifocal ( Trifocal ) lens implants are an expensive but innovative technology. They are designed to reduce your dependence on eyeglasses as compared to if you had a standard “single focus” lens implant. When you are not wearing glasses, a standard lens implant will provide your eye with optimum focus set at one particular distance that does not change. You would then wear glasses in order to change this focus (e.g., moving the focus farther away or closer up).
How does the multifocal work?
With bifocal eyeglasses, you look through the top part of the lens for distance, and through the bottom area of the lens for near. The multifocal lens implant is entirely different because the specially engineered optic provides both a distance focus, and a near focus at all times. Your brain will learn to automatically select the focus that is appropriate for the task at hand. An analogy might be having background music playing in the room during a conversation. Your brain might “tune out” one to listen to the other. There can be a brief learning curve for using this unique optical system. For example, you will need to learn the optimal distance to hold reading material. For this reason many patients report that their ability to function without glasses continues to improve over time.