Hazy, Blurry and Dim: An In-Depth Look at Cataracts, Part I
This week we will shift gears and focus on a condition that affects millions of Americans every year - cataracts. Cataracts may be the most “popular” of eye diseases in terms of Western discussion. Although you may find it lumped in with the "Big Three" of eye diseases (glaucoma and age-related macular degeneration being the other two), cataracts always seem to take the center stage due to their prevalence. Chances are, you have had a coworker, relative or friend that has been diagnosed with cataracts. You may have heard of someone having cataract surgery. Maybe you have been diagnosed with cataracts.
So what are cataracts?
First, let’s go through a brief eye anatomy lesson in order to understand what part of the eye a cataract affects – the crystalline lens. The lens of the eye sits behind the cornea (the clear front part) and the iris (the colored part), but in front of the vitreous and retina. The lens is responsible for refracting and focusing light so that the eye may achieve clear vision. In order to focus light, small muscles attached to the lens actually change its curvature and essentially "bend" the lens to focus light/images from different lengths!
A cataract occurs when the crystalline lens begins to become opacified. In simpler terms, the lens becomes dirty, foggy and less clear than it used to be. This creates a decrease in both visual acuity and visual quality. The easiest way to understand how a cataract affects vision is to think of a car windshield. When your windshield is clean, driving is easy, visibility is clear, and distortions such as glare are minimal. When your windshield is dirty (or fogged), driving becomes more difficult due to decreased visibility and glare.
What are the symptoms of cataracts?
So now that we have a general idea of what is happening with a cataract, let’s cover a list of the symptoms associated with cataracts:
- Blurred vision
- Inability to see in dim light
- Seeing halos around lights
- Vision loss
- Changes and desaturation to color
Why do cataracts occur?
Now the next question to answer is: why do cataracts occur? The answer to this question lies in a few different causes including:
- Excessive exposure to sunlight
- High blood pressure
- Previous eye injury or inflammation
- Previous eye surgery
- Prolonged use of corticosteroid medications
- Drinking excessive amounts of alcohol
The most common cause among all of the above is aging. As the body ages, free radicals in the form of chemical compounds and UV light slowly take their toll and create wear on the crystalline lens. This subsequently leads to a cataract. Reducing free radical damage in daily life is always useful in staving off cataracts. The easiest and most effective ways to do this are to wear sunglasses when outdoors and eat a healthy diet rich in antioxidants (and take a multivitamin as well as a vitamin C supplement). The idea of free radical damage also gives us insight into why smoking and excessive alcohol consumption can lead to cataracts.
While most cataracts involve age being a factor, certain individuals may be born with cataracts or develop them early in life. These individuals are said to have congenital cataracts.
Diabetes is a systemic condition that can lead to cataracts. In a later article, I will go into diabetes and its effects on the eyes in depth. Diabetic cataracts manifest themselves in a certain and often unique manner when I view them through a biomicroscope.
Previous eye injuries or surgeries are also a big cause of cataracts. Any sort of insult or trauma to the eye whether it be from the outside or the inside, can cause a cataract. This is especially true if the trauma touches the crystalline lens.
The final cause I will expand upon is corticosteroid medications. This is often the cause of early onset cataracts in patients I see. I remember seeing a patient in his early 40s that was developing a cataract, and we simply could not find a reason why! Finally, after extensive exploration of his medical history, we found out that he had been taking oral prednisolone earlier in his life. If you are being placed on a corticosteroid medication, always discuss side effects like cataracts with your doctor.
So now that we have explored cataracts and their causes in depth, the next logical question is what are the treatment options? Stay tuned for next week's article, where we will explore different cataract surgery options and the amazing technology behind them!
-Dr. Aaron Neufeld