In the U.S., there were 24.4 million cases of cataracts in 2010, and the number is expected to double to 50 million by 2050, according to the National Eye Institute.
What is a cataract?
A cataract is a clouding of the crystalline lens inside the eye which leads to a decline in vision. Aging is the most common reason for a cataract, but other factors include disease, trauma, and certain medications. Most cataracts grow slowly over decades, but some may progress more quickly.
The crystalline lens is the structure located in the middle of the eye, in front of the retina, but behind the iris (colored part). All light that enters the eye goes through the cornea and the lens to get to the retina. If a cataract is affecting the lens, distorted vision is the result. Glasses and contacts are unable to correct the vision until the cataract is removed.
Common signs of a cataract include:
- Blurry vision
- Increased glare/halos
- Color distortion
- Difficulty with reading
Common types of cataracts
The most common types of cataracts are nuclear sclerosis and cortical cataracts. The type of cataract and the location of the cataract inside the lens can have varying effects on vision. Cataracts that affect the back of the lens (posterior) can reduce vision more dramatically than those on the front side of the lens (anterior).
Nuclear sclerosis cataract
A nuclear sclerosis cataract typically occurs with age. Nuclear sclerosis is a hardening and yellowing of the central part of the lens (nucleus), and then, expansion into the other parts of the lens. Nuclear sclerosis cataracts grow slowly and may cause your prescription to become more myopic (more minus) over time. A doctor will grade the stage of the cataract from 1 to 4 depending on the change in color from yellow to brown. It typically takes many years until they begin to affect vision and need to be removed.
A cortical cataract looks like spokes when viewed by a doctor. The cataract forms in the cortex layer of the lens and then extends to the outside of the lens in a “spoke-like” manner. This type of cataract results in light scatters which creates problems with blurred vision, glare, contrast, and depth perception. Patients with diabetes are at risk for developing cortical cataracts.
Posterior subcapsular cataract
A posterior subcapsular cataract (PSC) begins as a small, opaque area on the back side of the lens. Again, a cataract that affects the back side will have a greater effect on one’s vision. A PSC cataract affects reading and night vision due to glare and halo effects created around lights. PSC cataracts develop rapidly, usually within a few months, and can significantly affect visual acuity. Individuals with a history of oral steroid use, diabetes, myopia (near-sightedness), and retinitis pigmentosa are more likely to develop a PSC cataract.
Posterior polar cataract
A posterior polar cataract (PPC) is a unique type of congenital cataract. There are five genes that have been linked with PPC. A PPC appears as a round central discoid plaque-like onion ring-shaped opacity composed of malformed lens fibers. The removal of a PPC cataract can be difficult because the incidence of posterior capsular rupture is very high during surgery.
Risk factors for developing cataracts
Factors that may put one more at risk for developing a cataract include age, sex, race, and myopia. Modifiable risk factors include smoking, socioeconomic status, and ultra-violet light exposure. It is possible alcohol intake and nutrition may play a role in cataract formation.
A cataract has also been associated with many systemic diseases, mainly diabetes mellitus, hypertension, obesity, chronic kidney disease, and autoimmune disease. Cataract development is also a sign of many metabolic disorders and syndromes.
When is the right time for cataract surgery?
There is no definitive standard for when your cataract should be removed, but when your vision is unacceptable with glasses and it is interfering with your day-to-day life and hobbies, it may be time to have it assessed.
Your eye doctor will evaluate the size, type, and effect of the cataract on your vision. Most medical insurance will cover surgery when one of two conditions is met. Your vision with your glasses falls below 20/40 or your potential acuity meter (PAM) testing demonstrates an improvement in your vision when the cataract is removed.
What to expect from cataract surgery
Surgical techniques and implanted lenses have evolved significantly in the last 50+ years. Recovery time is quick, and complications are few. Cataract surgery is performed out-patient and recovery is within a few hours. Prior to cataract surgery, an eye doctor will dilate your eyes to assess their health and perform some measurements and calculations to decide what type of intraocular lens will be implanted in the eye.
The patient will be awake during the surgery and the procedure is somewhat simple. The doctor will break up the natural lens in the eye, a process called phacoemulsification, and replace it with the new, calculated lens implant.
There are many different types of intraocular lens implants.
Depending upon a patient’s needs or desires, a distance lens or a multifocal lens implant may be placed in the eye. A distance-only lens is standard procedure. After surgery, the patient can expect to only need glasses for reading.
Multifocal implants are considered elective and are not typically covered by insurance; however, they may eliminate a patient’s need for glasses after surgery. Multi-focal lens implants provide distance, intermediate, and near correction for the patient. A discussion with your eye doctor and surgeon may be beneficial in determining the correct choice for you.
Can you prevent cataracts?
Most cataracts are due to UV exposure from the sun over the course of a patient’s life. Most sun exposure we have is before the age of 21. The lens in a child’s eye is not fully developed and allows 70% more UV rays into the eye than an adult’s eye. Just like wearing a hat and sunscreen outside, it’s important to wear sunglasses daily. Even when it is cloudy, light rays are present. Maintaining a healthy lifestyle and habits are also key to cataract prevention.
In addition, avoiding or quitting smoking can decrease your risk of cataract formation.
While most of our grandparents had cataract surgery, with a healthy lifestyle it’s possible to avoid cataract surgery. If you do need surgery, with a good surgeon, you can be confident in a good outcome and great vision!