Cataracts are a progressive and painless clouding of the internal lens of the eye. Cataracts block light, making it difficult to see clearly and are a very common eye condition, especially as we age. According to the National Eye Institute, by age 80 more than half of all Americans either have a cataract developing or have had cataract surgery. Cataract affect more than 24.4 million Americans age 40 and older. They can occur in either or both eyes, but once a cataract is surgically removed, it cannot return in that eye! Certain diseases, such as diabetes, put you at greater risk of developing cataracts, as well as lifestyle choices such as smoking and alcohol use. The environment or area where you live could also influence your risk. Cataract prevalence has been shown to increase with proximity to the earth's equator, where the population has more exposure to strong ultraviolet (UV) sunlight. Cataracts can also develop as a result of exposure to some types of radiation and a result of trauma in or around the eye. Additionally, some babies are born with congenital cataracts, which may or may not affect their vision.
Cataract symptoms include:
- Blurry, dim, or hazy vision
- Increased glare at night or starbursts, halos around lights
- Muted or desaturated color vision
- Difficulty reading and driving
- Poor night vision
- Double vision in a single eye
Some patients describe a frosted window appearance to their vision. Others notice isolated and localized fuzzy spots in their visual field. You should never ignore changes to your vision. If you notice things starting to look cloudy, distorted, or blurry, you could be developing cataracts. The only way to know if cataracts are the cause of your vision changes is to visit an eye care professional. Thanks so vision simulations for such a great job on the representations.
When a cataract forms, the cataract will form on your lens sitting just behind the pupil. The lens is responsible for focusing light onto your retina for your brain to process. A healthy young lens is crystal clear, but a cataract causes the lens to become cloudy, yellowed, and opaque. This yellowing of the lens helps protect your retina from ultraviolet radiation from the sun but can also cause decreased vision over time. Imagine looking through a dirty car windshield that you cannot clean. Your risk for developing a cataract in one or both eyes increases substantially as you age and is currently the leading cause of blindness worldwide.
Additional information about the Eye Lens and role it plays: The eye lens is an elliptic structure made up of elongated cells and suspended in the eye by zonules that connect it to the ciliary body. The contraction and relaxation of the ciliary body muscles is what causes the lens to change its shape and thus focus light on the retina. The lens will flatten itself to focus on objects far away and become full and round to focus on objects at close range. The lens has no blood supply but obtains its nutrients and disposes of its waste through the fluid of the eye that surrounds it, called the aqueous humor. The lens will continue to grow as we age and with this growth comes more curvature and a forward movement of the lens. This can lead to additional problems with a decrease in the depth of the anterior chamber and angle closure glaucoma.
Cataracts are named according to their location or cause and are graded by your eye doctor based on severity. There are several different common categories of cataracts your Optometrist could diagnose, including senile nuclear sclerosis, cortical cataracts, posterior subcapsular cataract, traumatic cataracts, diabetic cataracts, and congenital cataracts. We will discuss each one below:
1. Nuclear Sclerosis - this kind of cataract is associated with oxidative damage to lens fiber cells. Lens brunescence can accompany nuclear cataracts caused by an increase in chromophore concentration. The increase in the yellow coloration causes the absorption of wavelengths in the blue end of the visual spectrum. Although less popular now days, remember when Grandma or her friends went a little heavy on the blue hair rinse? Turns out, there is an explanation for that extra blue look. As we age, some people notice hair can turn an ivory or yellowish color that is not attractive. To combat this, many turn to blue hair rinses to balance out the yellow. But with nuclear sclerotic changes, your eyes become much less sensitive to the color blue. So in Grandma’s eyes, their hair is a nice even shade of white and the rest of us were seeing…. well smurfville.
2. Cortical Cataract - these have a spokelike shape, much like the wheels of a bike. Cortical cataracts are thicker in the periphery and taper toward the lens center. With time, the spoke width expands and the opacity spreads. Optometrists grade these cataracts by how many quadrants of the lens are affected by the spokes. Cortical cataracts generally affect vision only when they progress into the center of the lens and result in a light scatter, such as with oncoming headlights or street lights.
3. Posterior Subcapsular Cataract - this is a lens disturbance located just beneath the posterior capsule. It can result from an accumulation of epithelial-like cells caused by abnormal cell migration or anomaly of the lens fibers. A significant risk factor for a posterior subcapsular cataract is long-term steroid use.
4. Traumatic Cataract - a cataract that results from some kind of ocular injury. This could be blunt-force trauma from participation in contact sports or being hit with a ball. A burn, chemical exposure, or penetrating foreign body could also cause a trauma-related cataract. These can appear as a rosette shaped opacity if associated with blunt force trauma or small focal cortical changes if a result of penetration into the globe.
5. Diabetic Cataract - these can develop very rapidly and results from elevated glucose levels. With increased glucose in the bloodstream comes increased levels of glucose in the aqueous humor which bathes the lens. This excess of glucose causes an increase in sorbitol concentration. However, the sorbitol cannot easily pass through the lens fiber membrane. Therefore, water is drawn into the lens instead and the lens fibers swell, decreasing the transparency of the lens and is one of the causes of loss of vision in diabetic patients.
6. Christmas Tree Cataract - this is a rare type of cataract identified by polychromatic (often red and green colors) needle shaped deposits in the lens nucleus and cortex. They are associated with a condition called myotonic dystrophy.
7. Anterior Polar Cataract - these are congenital cataract and can affect about 3 out of every 10,000 children. This cataract often looks like a small dot on a child’s eye that can be seen in the middle of the black pupil. The majority are very small and because of their size, do not need to be removed, only monitored for changes. Some may be larger or may progress over time to the point where they would need surgical removal in order to prevent a condition called amblyopia (or lazy eye).
Below are examples of the following 7 cataracts starting from left to right.
An eye doctor diagnoses cataracts during a comprehensive eye exam. The doctor dilates your pupil with special pharmacological eye drops and examines your eye using a slit-lamp biomicroscope, which makes abnormalities easy to detect. Dilation is an important step in diagnosing cataracts because a small, undilated pupil makes the lens difficult or impossible to see. Your visual acuity will be tested and a refraction will be performed to see if your vision can be improved by a new or updated glasses prescription. If your vision can be well corrected with a prescription, it is unlikely that the cataract is very advanced.
First, your doctor will determine if your vision can be corrected with a new or updated prescription for corrective lenses. If your cataract is in the early stages, it may not drastically interfere with your vision, so eyeglasses or contact lenses may be enough to improve or restore your sight. However, once a new prescription no longer helps, it’s time to consider cataract surgery. The decision to proceed with cataract surgery is determined by the cataract’s effect on your everyday life. When you are no longer able to perform your usual daily activities comfortably or to the best of your ability, the cataract should be removed. But don’t worry—there’s no reason to rush into surgery. Untreated cataracts won’t usually harm your eyes if you decide to wait and see how the condition progresses—it will simply cloud your vision further until you have it removed.
Rest assured that eye surgery is a safe treatment option for cataracts. Your eye surgeon removes your clouded lens, then replaces it with a synthetic intraocular lens (IOL). Your doctor may suggest a new laser-assisted approach when installing multifocal or extended-range IOLs capable of correcting nearsightedness, farsightedness, and astigmatism, as well as restoring your vision clarity. This could eliminate the need for corrective lenses for most everyday activities. As an outpatient procedure, the recovery time from cataract surgery is minimal. Aftercare involves using eye drops including broad-spectrum antibiotics and strong ophthalmic corticosteroids to prevent infection and inflammation while your eye heals. You will also need several follow-up visits with your surgeon to ensure a good outcome. Complications and side effects of cataract surgery are rare and include infection, bleeding, and retinal detachment. Your surgeon and their team will make sure you know about the risks and benefits of cataract surgery before you schedule your procedure. They will also discuss all the various lenses and latest technology that is available to you.
Medicare and other major medical insurance plans cover medically necessary vision services, including cataract surgery, thus greatly reducing the price you pay out of pocket for this procedure. You of course will still have deductibles, coinsurance, and non-covered services that are your responsibility. The total cost will depend on many factors, including whether you choose a covered standard lens implant or decide to upgrade to newer lens implant technology with added benefits such as focused vision in both the distance and near point range. This could potentially eliminate the need for corrective lenses following surgery. New lens technology will add a significant cost as a non-covered material. The location of your surgery, any special precautions that need to be made for your procedure, and the technology used to perform the extraction will all cause your costs to vary slightly.