A cataract is a gradual clouding over of the lens in the eye that can cause a range of vision problems. The lens is responsible for transmitting light to the retina at the back of the eye; it adjusts our focus and allows us to shift between looking at objects that are close up to ones that are at a distance.
The eye and its lens are made up mostly of protein and water. As we age, the proteins may clump together creating areas of cloudiness and opacity that make up cataracts. There are several types of cataracts that can affect the eye. They are separated in to three distinct groups based on where the formation of the obstruction begins:
- Nuclear cataract: most commonly attributed to age-related factors, nuclear cataracts begin in the center of the lens and slowly radiate outwards. Double-vision is common when suffering from a nuclear cataract. As the occlusion progresses it may even turn yellow or brown in color and cause further interference in the ability to differentiate between colors.
- Cortical cataract: beginning its progression in the opposite manner of the nuclear cataract, cortical cataracts begin at the radial edges of the lens and extend inwards as they progress. An increase in glare and light sensitivity are common with this type of cataract, which also commonly affects people suffering from diabetes.
- Subcapsular cataract: sometimes referred to as a posterior cataract, these begin at the back of the lens. This interferes with the direct pathway of light travelling through the lens to the retina and causes problems with reading, light sensitivity and night vision. Subscapular cataracts are also common in diabetics.
Causes of Cataracts
While there may not be any one element that is solely responsible for the development of a cataract, the following are the most common causes:
- Age: with aging comes an increase in several risk factors that have a direct effect on cataract development, including type 2 diabetes, high blood pressure, long-term UV exposure, obesity and prolonged use of corticosteroids.
- Smoking: studies have shown that prolonged smoking can lead to an increased risk for developing cataracts.
- Previous eye-surgery or eye-injury: any damage or inflammation of the eye can make it more susceptible to cataracts, compounding the risk of cataracts in elderly people.
Whatever the exact cause, age is by far the biggest determining factor in developing cataracts, with the risks growing exponentially as people grow older. While only 42% of people between the age of 52-64 report vision problems due to changes in their lens the number increases all the way to 92% by the time people reach the age of 85
As cataracts develop, light is distorted when passing through the lens of the eye, thus causing visual impairment. A person with cataracts often describes their vision as looking through a dirty windshield of a car or a camera lens covered with a light film.
Common symptoms of cataracts may include:
- Blurred vision: vision may begin to blur, seeming as if you’re looking through a piece of cloudy glass or as if there is an irritant affecting your eyesight.
- Myopia: often in the beginning stages of age-related cataracts, near-sightedness may occur making objects in the distance seem blurry while images up close remain clear. Sometimes there is even an overall improvement in vision, known as second-sight, wherein the affected person’s vision actually becomes better for a short period of time before degenerating.
- Light sensitivity: both natural and artificial light may become glaring and make activities in sunny or well-lit areas difficult. Night vision will also be affected, making streetlights or oncoming headlights from cars appear more intense than before.
- Fading of colors: colors may also begin to appear less intense, especially in the blue spectrum.
If you notice vision changes or are having problems with light sensitivity make sure to schedule a visit with an ophthalmologist. The earlier you discover what the problem is, the more options you will have at your disposal for treatment, shortening your overall recovery time and giving you the best possible chance at continued clear vision.
Testing & Diagnosis
A cataract is the clouding over of the lens of the eye. Early form of cataracts may not pose a threat, but later it can impair vision which makes it difficult to read, drive a car, or see the expression on someone’s face.
Ophthalmologists and optometrists have several tests at their disposal to diagnose cataracts. These include:
- Visual acuity test: This test measures how well you can see at varying distances. Your doctor will ask you to read out loud a set of letters on an eye chart. This test is done using one eye to look at the letters while the other eye is covered. There are various sizes of the letters to determine whether your vision is impaired.
- Slit lamp: Another test that can be done is a slit-lamp examination, which allows your doctor to use light and magnification to see into your eye. These slits in the light allow the doctor to see tiny abnormalities within the structure of the eye. This is very helpful in determining what could be the cause for impaired vision.
- Pupil dilation: The doctor uses drops to dilate your eyes causing the pupil to increase in size allowing the doctor a clear view into the lens of the eye. With this examination (retinal exam), a doctor will be able to tell for sure if a cataract is impairing your vision.
Cataract Eye Surgery
Eye surgery is the primary course of action when treating vision loss caused by cataracts. Most doctors recommend this surgery when cataracts start to affect a person’s quality of life. With cataract surgery, the lens of the eye is replaced with an artificial lens such as intraocular lens implant (IOL). When a person has complications where an artificial lens cannot be used, then the cataract is removed and the person continues on with glasses or contact lenses to correct their vision.
Most cataract procedures today involve the use of a ultrasound device to break up the cloudy lens into small pieces, which are then removed by suction from the eye. This is known as Phacoemulsification, or Phaco. During Phaco, a topical anesthetic is applied to the eyes before treatment to minimize any discomfort or pain associated with the procedure. Once the cataract has been removed, an IOL is placed into the remaining lens capsule to restore vision. Depending on the type of IOL used, a larger incision may be required. If using a smaller, foldable IOL, the incision will not require suturing.
This is performed as an outpatient procedure requiring less than a couple of hours to be completed.
Laser Cataract Surgery
Laser cataract surgery, also referred to as a ‘bladeless’ technique, is a new form of surgery that uses femtosecond laser technology to treat cataracts. Harnessing the technology responsible for the advanced accuracy and safety of LASIK surgery, laser cataract surgery improves the precision of treatment, resulting in better vision outcomes than traditional surgical methods.
Laser cataract surgery is in its infancy, having only been performed in the United States for the last several years. As such, not all eye surgeons offer it as a cataract treatment. However, there are at least four companies currently developing lasers specifically for use in this procedure. The FDA-approved LenSx femtosecond laser is the type that is most often used to perform laser cataract surgery.
As with other types of cataract surgery, this is an outpatient procedure. Patients are awake throughout, with anesthetic eye drops used to numb the eyes. The surgeon first creates an incision in the cornea to gain access to the cloudy lens of the eye. In traditional cataract surgeries like Phaco, this incision is cut with a handheld surgical blade. A benefit of laser-assisted cataract surgery is that the femtosecond laser is used to create the incision. The surgeon then uses the laser to enter the lens capsule, where the cloudy lens is broken apart into smaller pieces for removal. Finally, the eye’s natural lens is replaced with an intraocular lens (IOL), an artificial lens intended to replace the eye’s natural lens. This step is performed in the same manner as in traditional surgery.
Laser cataract surgery is believed to be even safer than its traditional counterparts. However, as with all surgical procedures there is some degree of risk. Potential complications include infection, inflammation, or rotation of the artificial lens out of position, which may require revision surgery. The back of the implanted lens can also become cloudy, a condition known as posterior capsule opacity. While this leads some patients to believe their cataract has returned, it can be treated to restore the patient’s vision.
No stitches are required to close the incisions created during laser cataract surgery. Patients are free to return home immediately, though they will need someone to drive them. Recovery is typically shorter than that required with other forms of cataract surgery. Most patients take a few days to a week away from driving, working and other activities that may increase blood flow or pressure in the eye. Halos, glare or other vision disturbances may be experienced until the eyes have fully healed, which takes about a month.
Laser-assisted cataract surgery is typically more expensive than other cataract treatments. Additional costs associated with the laser equipment can add several thousand dollars to the cost of surgery, which is traditionally $2,000 to $5,000 per eye. It is likely that the laser-assisted method will add between $200 and $1,500 to your total cost.
- Age Related Cataract: Author: Vicente Victor D Ocampo, Jr, MD; Chief Editor: Andrew A Dahl, MD, FACS
- AAO: What are Cataracts? Reviewed by Elena M Jimenez MD; Written by Kierstan Boyd (n.d.)
- NEI: Facts about Cataract (n.d.)