More than half of all Americans will have dealt with cataracts by the time they are 80, yet many people still do not know what they are or what causes them. Cataracts are common among those over the age of 50 and are characterized by a clouding of the eye’s natural lens, resulting in blurry vision.
Currently, the surgical removal of the lenses and subsequent replacement with artificial intraocular lenses (IOLs) is the only cure for cataracts. Fortunately, cataract surgery is a low-risk procedure with an excellent record of safety and success.
Cataracts form when proteins begin to clump together in the lens, clouding a small area of the eye. This cloud will continue to grow and interfere with vision. Cataracts can occur in one or both eyes. While the most common cause of cataracts is age, they can also be caused by eye trauma, certain medications, and various environmental and lifestyle factors. Additionally, some cataracts are congenital.
Your eye is composed of protein and water. If the protein cells separate from your eye, they will eventually drift onto the natural lens located behind your pupil. This will prevent light from passing completely through the lens and focus properly on your retina, resulting in obscured vision. As light passes through your eye, the lens refracts the light, focusing it on the retina. As the cataract grows, vision becomes progressively worse.
In part, cataracts develop because of the process of oxidation. Free radicals roam throughout the body. These oxygen molecules stabilize themselves by taking electrons from nearby molecules. In response, these molecules will attempt to self-stabilize by taking an electron from another molecule, and the cycle continues until it affects more and more cells. As this process, known as oxidation, occurs in the eye, it can lead to the development of cataracts.
Types of Cataracts
There are three types of cataracts, each defined by its location on the lens:
- Nuclear cataracts, which form in the lens’ nucleus, are the most common type of cataracts. Because opacity develops in the center of the lens, known as the central nucleus, nuclear cataracts interfere with a person’s ability to see objects in the distance. Usually the result of advancing age, nuclear cataracts can take years to develop and often give the nucleus a yellow tint.
- Cortical cataracts begin at the outer rim of the lens and gradually work toward the central core. Thus, this type of cataract resembles spokes of a wheel. Patients with cortical cataracts often notice problems with glare, or a “halo” effect around lights. They may also experience a disruption of both near and distance vision.
- Subcapsular cataracts progress the most rapidly. While nuclear cataracts take years to develop, subcapsular cataracts reach an advanced stage within a matter of months. Posterior subcapsular cataracts affect the back of the lens, causing glare and blurriness. This type of cataract is usually seen in patients who suffer from diabetes, extreme nearsightedness or retinitus pigmentosa, as well as among those who take steroid medication.
Congenital cataracts refer to cataracts that are present from birth, as well as to those that develop in early childhood. These cataracts can be nuclear, cortical, or subcapsular. Congenital cataracts may be linked to an infection contracted by the mother during pregnancy or to a genetic condition such as Fabry disease, Alport syndrome, or galactosemia. Because clear vision is essential to the development of the child’s eyes and brain, it is important to diagnose congenital cataracts as early as possible.
Because each of these cataract types affects vision in a distinct manner, it is possible for a patient to have more than one type of cataract at the same time.
Most cataracts form as a result of advancing age. Other possible causes of cataracts include environmental factors and certain medications, such as antidepressants. If your medical history or lifestyle increases your risk of developing cataracts, it is important to have your eye health monitored regularly by a qualified ophthalmologist.
Over 50 percent of Americans over the age of 80 have cataracts
Age is the main reason cataracts form. According to the American Academy of Ophthalmology, the eye disease appears in over 22 million Americans over the age of 40. Over 50 percent of Americans over the age of 80 have cataracts. In fact, if we live long enough, nearly all of us will eventually develop this condition. Because the lens of the eye cannot shed old cells naturally, protein that accumulates on the lens gradually builds up over time, progressively obscuring vision by preventing light from reaching the retina.
Ultraviolet Radiation (UVA or UVB)
According to the U.S. Environmental Protection Agency, long-term exposure to ultraviolet radiation, especially UVB rays, can cause changes in pigment that lead to the formation of cataracts. This is especially common in tropical climates, where high concentrations of UV exposure occur year-round. To protect the eyes from sun damage, it is important to wear sunglasses with a high level of UVA/UVB protection.
Certain medications are well-known causes of cataracts, and some drugs can also accelerate their development. Steroid medications – whether pills, injections, or eye drops – are most frequently associated with cataract formation. If you are taking steroid medications to manage a long-term condition, it is important to note any visual changes and to have your ocular health managed by a qualified ophthalmologist. The medications that can cause cataracts include:
- Eye drops containing steroids
- Glaucoma medications
- Certain antipsychotics and antidepressants
- Certain medications for autoimmune conditions
- Medication to control heart arrhythmia
High levels of blood sugar cause the lens of the eye to swell with excess fluid, making diabetic patients more susceptible to cataracts and glaucoma. People who have diabetes are more likely to develop cataracts at a younger age, and experience rapid cataract progression. Careful monitoring of blood sugar levels helps to minimize the risk of developing cataracts.
Obesity is most commonly linked to the development of posterior subcapsular cataracts. According to researchers at Harvard University, individuals with a BMI of 33 had at least a 30 percent greater likelihood of developing cataracts, compared to subjects with a BMI of 23 or below.
Injury, Inflammation, or Trauma to the Eye
Injury or trauma to the eye increases a patient’s risk of developing cataracts. Individuals who have experienced inflammation in the eye, either post-operatively or as the result of another eye disease, are also more likely to eventually develop cataracts. For instance, iritis is an ocular condition that causes chronic inflammation inside the eye, and is commonly linked to early and rapid cataract formation.
Lifestyle habits such as smoking or consuming alcohol are often considered causes of cataracts. In 2012, the Investigative Ophthalmology & Visual Science published a study performed by Chinese researchers on the correlation between smoking and cataracts. The scientists found that smokers were at a significantly higher risk for cataracts, with current smokers showing the highest rate of cataracts development. These individuals were most at risk for nuclear and subcapsular cataracts. Some doctors attribute the connection to the high level of free radicals present in the bodies of smokers, placing them at particular risk of developing nuclear cataracts.
Alcohol is responsible for a slight increase in the likelihood of cataract development, and the level of risk directly correlates to the amount of alcohol consumed. For both eye and overall health, it is recommended that drinking be limited to moderate amounts.
Maintaining healthy eating habits can help to prevent cataracts in two ways. First, a good diet will control your weight, thus eliminating one of the significant risk factors. Second, increasing your antioxidant intake can also inhibit the oxidation process. In a 2013 Swedish, researchers observed 30,000 women over age 49, and found that those who consumed the highest amounts of antioxidants had a 13 percent lower chance of developing cataracts than those who consumed the least amounts.
To reduce your risk for cataracts, be sure to eat plenty of foods high in antioxidants. These could include:
- Colorful fruits and vegetables
- Whole grains
- Red wine
- Poultry and red meat
- Sunflower seed
In addition to changes in diet, there are several other modifications you can make to protect your eye health:
- Stop smoking: As stated above, current smokers have a significantly higher chance of developing cataracts.
- Wear sunglasses: Be sure to look for lenses with 100-percent UV protection. To ensure that you are receiving quality lenses, purchase sunglasses from your ophthalmologist. If you purchase them elsewhere, don’t assume that just because the label says they offer complete UVA/UVB protection, they actually do so. Ask you eye doctor to check the percentage before you wear them.
- Protect your health: If you have another health condition, such as diabetes, that increases your risk for cataracts, seek treatment for these concerns. If you have diabetes, keeping your blood sugar under control is one of the most important things you can do to protect your eye health.
- Exercise: Although workouts themselves will not affect your eyes, an active lifestyle will help to manage your weight. Of course, if you choose outdoor activities, be sure to wear your sunglasses.
Routine Eye Exams
When you make regular visits to your ophthalmologist, he or she can monitor your eye health and look for cataracts in the early stages. With early diagnosis, your doctor can treat the condition before it begins to impinge upon your quality of life. Typically, you should have an eye exam once a year, although if you are at a higher risk for cataracts, you should make biannual visits.
There are a number of signs that may indicate that you are suffering from cataracts. Common cataract symptoms include:
- Blurred vision: When cataracts cloud your lens, light cannot focus on the retina properly, and your brain will register a distorted image.
- Difficulties with night vision: With cataracts, your retina is already receiving less light, and therefore, in dim light your sight is compromised even further. This can be especially problematic when you are driving at night.
- Halos and light sensitivity: Cataracts cause the light passing through your eye to scatter, so that it hits your retina in several different places. This can cause discomfort and vision difficulties in bright light.
- Difficulty distinguishing colors: If you have cataracts, you may have problems perceiving hues on the blue end of the color spectrum. As a result, objects may appear yellow or simply dull and faded.
- Rapid changes in vision: If you experience swift and repeated changes in your glasses or contacts prescription, this can be an early sign of cataracts.
- White spots on the pupil: On occasion, your cataracts may be visible to an observer, especially when viewed at certain angles or under specific lighting conditions.
Progression of Cataracts
Of course, the frequency and degree of your symptoms will depend on the severity of your cataracts. Symptoms and treatment will vary, depending on whether your cataracts are in the early or advanced stage of development.
In the early stages, indications include changes in vision, such as glares, halos, difficulties with night vision, etc. Often, these symptoms are so slight and progress so slowly that people don’t even realize they are present. It is not unusual for cataracts patients to seek treatment only because family members have pointed out that they seem to be having difficulties. In some instance of early stage cataracts, you may develop what is known as “second sight,” in which your close up vision will actually improve before your eyesight starts to decline over all.
Advanced cataracts will cause more severe changes in your eyesight. Without treatment, you may have difficulty distinguishing facial features and completing daily tasks. The rate at which your cataracts develop will depend on several factors. Typically, if you are at a higher risk for cataracts, for any of the reasons described above, your cataracts will develop more quickly.
Cataracts are fairly easy to diagnose. Nevertheless, for the most accurate diagnosis, there are a number of advanced tests that your doctor may use. Utilizing these diagnostic tools, your doctor can also check for an additional eye disease, such as glaucoma or macular degeneration.
Visual Acuity Test
When you think of a routine eye exam, this test is probably what you picture. Your doctor will ask you to read a series of letters off of a Snellen eye chart posted 20 feet away from you. This test allows him or her to detect any significant changes in your vision.
If you have already been diagnosed with cataracts, and your vision has degenerated to 20/40 or below, your doctor may recommend surgery. In some cases, you may have a good score on this test, but you still present with other cataract symptoms, such as light sensitivity or blurred vision. When this occurs, your ophthalmologist will likely recommend more tests to determine whether cataracts are, in fact, responsible for your symptoms.
Slit Lamp Exam
Your doctor will give you eye drops to dilate your pupil. By shining a light on the front of your eye, he or she can usually detect any white spots on your lens, even if they are very minute. The slit lamp exam often allows for extremely early diagnosis, so that your ophthalmologist can detect cataracts before they begin to affect your vision. During the test, your doctor will likely use a magnifying lens to examine your retina and optic nerve. Although this step is not necessary for cataracts detection, it enables your doctor to check for other serious eye conditions.
Glare and Contrast Sensitivity Tests
These two tests are similar to a traditional visual acuity test.
During a glare test, you will be asked to read the Snellen chart under various lighting conditions. If you have difficulty discerning the letters under very bright light, this could be a good indication of cataracts.
Contrast sensitivity tests use different kinds of charts; instead of the letters getting smaller as they go down the chart, they “fade,” or contrast less with the white background. If you are unable to read all but the most defined rows of letters, this, too, could be an indication of cataracts.
Ishihara Color Test
Named after its designer, Dr. Shinobu Ishihara, this test uses a series of plates covered with colored dots. The dots vary in color, forming a number in the center of the plate. Those with an inability to distinguish hues on the blue-green end of the spectrum will not be able to see the numbers. If you have not been previously diagnosed as color blind, and you do not pass the Ishihara color test, you may be suffering from advanced cataracts.
Your ophthalmologist will direct a puff of air towards your eye, and it will measure the intraocular pressure (IOP), determined by the amount of vitreous fluid inside your eye. Although tonometry tests are most commonly used to diagnose glaucoma, it is important that your doctor be as thorough as possible during cataract diagnosis. When left undiagnosed and untreated, glaucoma, macular degeneration, and similar eye diseases can have dramatic consequences for your vision and ocular health.
When to Consider Surgery
During cataract surgery, your doctor will remove the old, clouded lens and replace it with an artificial intraocular lens, or IOL. Fortunately, cataracts only affect your lens, and therefore, there is no rush to undergo cataract surgery.
Typically, doctors will recommend surgical treatment when your condition has started to affect your daily life. If you find that it is difficult to complete certain daily tasks, or if you are no longer able to see objects or faces clearly, it may be time for surgery. If you frequently drive at night, you should undergo surgery sooner, as the nighttime glare can pose a serious risk for accidents. (In the meantime, you should avoid night driving, resuming it only when you have recovered from your cataract surgery.)
Alternatively, your ophthalmologist may recommend surgery if you do not receive a good score on your visual acuity, glare, contrast sensitivity, or Ishihara color tests. Ultimately, the decision to undergo surgery is your own, but your doctor can help you decide when it would be most beneficial to your health and quality of life.
Treatment for Early Stage Cataracts
Before surgery becomes necessary, there are a number of methods that your doctor may employ in the treatment of your cataracts. In the early phases, he or she may recommend new glasses or contacts, anti-glare lenses, and magnification devices. In most cases, however, these treatments will only work for a time. As your cataracts grow, surgery will typically be in your best interests.
Fortunately, virtually all insurance companies cover the cost of cataract surgery, as it is necessary to restore your vision and quality of life. However, the final cost of your procedure can vary significantly, depending on several factors, and there may be some costs you will need to cover out of pocket.
The Type of IOL
Typically insurance companies will only cover the cost of standard cataract surgery, which includes placement of a basic monofocal IOL. These lenses only correct vision at one distance. Premium lenses provide vision correction at varying distances, but these lenses typically cost more. If you choose to receive a premium lens, your insurance will usually cover the cost of basic surgery, and you will be responsible for any additional fees.
Astigmatism occurs when your iris is irregularly shaped, and therefore your vision is blurred at all distances. If you suffer from this condition, as well as cataracts, you may benefit from limbal relaxing incisions (LRI) before your procedure. After your doctor makes tiny incisions in the limbus (the tissue that connects the cornea and the white of your eye), your iris may relax and become more rounded as it heals. LRIs typically cost about $500 per eye, and they are not covered by insurance. Astigmatic keratotomy (AK) is a similar procedure, in which your surgeon will make two incisions at the steepest portion of your cornea. Insurance companies also do not typically cover AK.
You may also benefit from a toric IOL, the only type of intraocular lens proven to correct astigmatism. Again, these premium lenses do cost more than traditional monofocal lenses, and the extra cost is not covered by insurance.