Cataracts
What is a cataract?
A cataract is cloudiness in the normally clear and transparent lens. When present to a significant degree, the cloudiness obstructs vision by interfering with the passage of light to the retina.Everyone is born with a human crystalline lens within the eye. This transparent structure is located behind the iris and in front of the gel-like material in the back of the eye known as the vitreous.
The lens function is to focus rays of light and produce a sharp image on the nerve layer at the back of the eye, the retina. This image is then transmitted by the optic nerve to the brain where one perceives sight.
Causes & Symptoms
A cataract can be produced by injury, aging, medications or by diseases, such as glaucoma or iritis. When the lens is clouded significantly, decreasing the amount and quality of light that is transmitted to the retina, thus causing this blurry image, will obstruct vision. This is analogous to a dirty window; one can see but it is not clear.
As a cataract forms, the lens becomes opaque and light cannot easily be transmitted to the retina.
The amount of light and lighting conditions are of vital importance to the patient who has a cataract. Often they will notice that their vision is materially different at different times of the day. One of the early symptoms can be blurring of vision, particularly in very bright sunlight or on dark evenings. One has a tendency to see clearly in a room with good fluorescent-type lighting.
Since there are many different types of cataracts in different layers of the lens, the symptoms will vary from patient to patient. Some types of cataracts can cause a marked decrease in reading vision only, while others cause a decrease in distance vision only.
Cataracts can be formed at birth and progress rapidly, can be stationary or can progress with advancing age.
Treatment
Lens Implants | Laser TreatmentCataracts are considered to be the leading cause of disability and blindness in the United States. As with all eye diseases, the most important thing is diagnosis and examination to search for other possible associated conditions and diseases. The first attempt is to give optimum eyeglasses for extended periods to maintain vision as long as possible.
If and when a cataract progresses to the point that it interferes with the visual needs of the patient, then surgery is indicated. It is important to emphasize that a cataract should be removed only when it is interfering with the visual needs of the patient. Repeat follow-up examinations are important to be assured that the cataract is causing no damage to the eye.
A cataract is "ripe" or should be considered for removal when visual loss is significant and is hampering your lifestyle. Your eye must be examined to be sure that the vision loss is due to the cataracts. If this is so, then the next step is to understand the pros and cons of surgery and what can reasonably be expected. If the explanation is acceptable to you, then the next step is to talk about what can be done to give you your best vision postoperatively.
There are many different types of cataract removal from ultrasonic phacoemulsification extracapsular surgery, to a modified planned extracapsular, to intracapsular surgery. Phacoemulsification is considered the most advanced state of the art procedure. Because there are different types of cataracts, the procedure that is best suited for your particular type is the one that should be done. The most important thing to consider is that your surgeon should do the operation best suited for your eye.
All types of cataract surgery will remove the cataractous lens. With this lens out of the eye, the eye can no longer focus. As a result, all types of cataract surgery require some type of refractive assistance.
The conventional, older eyeglasses can provide excellent vision but are limiting in the peripheral vision and are thick, heavy "Coke bottle-type" glasses. They increase the size of objects by at least 25 percent and cause optical distortion. Many patients are quite unhappy with traditional cataract spectacles.
Contact lenses are also an option. These are worn on the corneal surface and provide good vision straight ahead and to the sides and only cause about a 6 percent magnification. The obvious problems and difficulties in dealing with a contact lens are a handicap. The newer, extended-wear contact lenses, which may be worn for weeks or months, are available and these have helped patients dramatically.
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| Clear, normal-image vision | “Clouded” image of a cataract |
INTRAOCULAR LENS IMPLANTS
The intraocular lens implant is an artificial plastic lens that is surgically placed inside the eye, into the capsular bag from which the cataract is removed, and is held permanently in place. It does not need removal or cleaning. This provides magnification of less than 1 percent and is well tolerated by the patient.
Implants definitely are the preferred method of restoring "normal" vision after cataract extraction. Newer types of implants have improved the quality of vision obtained after surgery. The "foldable" lens allows us to place an implant through a smaller incision. This allows restoration of normal vision faster with less post-operative fluctuation of vision and astigmatism. The smaller incision allows faster recuperation with almost no post-operative restrictions on activity. Bifocal implants, which are opening new horizons for visual improvement, are now available.
It is usually necessary, after either a contact lens or an intraocular lens implant, to use regular glasses or bifocals. These usually can be fitted approximately 3 to 4 weeks after the surgery. These are not the thick, heavy glasses and do not give the aberrations and magnification of the older type cataract lenses. The new "small incision surgery" allows quicker healing time and a decreased post-operative period.
The surgery is not painful or very prolonged, taking approximately 10 minutes. The procedure itself is usually carried out under topical anesthesia. The patient can go home on the same day.
It is unusual to have significant pain, though the eye will feel scratchy and vision will fluctuate for a period of weeks.
Patients will need to use eye drops during the weeks following surgery. Activities can be resumed rapidly.
As with any surgery, there are possible complications. Surgical results cannot be guaranteed and complications can occur during or after an operation. These complications can include pain, infection, bleeding, glaucoma or retinal problems. However, all of these complications are rarely encountered. Cataract surgery, with the advent of microsurgical techniques, is one of the safest surgeries currently being done today.
Alcon's AcrySof® ReSTOR Intraocular Lens (IOL) can substantially restore a cataract patient's ability to see both near and distant objects without the aid of reading glasses or bifocals. The ReSTOR IOL's innovative lens optics allows for a greater range of accommodation, thereby eliminating or significantly reducing dependence on reading glasses following cataract surgery.
AcrySof® Toric IOL The AcrySof® Toric lens is a foldable, singlepiece lens that an eye surgeon implants during cataract surgery to replace the clouded lens.
LASER
When you remove the cataract you purposely leave the posterior capsule of the lens. This posterior capsule can cause similar visual problems as a cataract. It is estimated that between 5 and 20% of patients having capsular extraction within a five-year period will need an opening of this membrane or a capsulotomy. To restore vision, an opening must be made in this cloudy membrane. If this membrane clouds up it can be opened with a laser. This is a non-invasive procedure. The new laser is known as the ND: YAG laser. This new technology has allowed us to leave the posterior capsule intact with all the inherent advantages, knowing that we can attack it at a later time with this laser, which will not be especially costly or a dangerous procedure for the patient, should it become necessary.The word ND:YAG stands for the components of the laser: Neodymium, Yttrium, Aluminum and Garnet. Since the light beam from the YAG laser is invisible, a beam of red light is used as an aiming beam. The difference between this laser and lasers that are used for blood vessel treatment in the back of the eye is that this laser can actually cut tissue inside the eye without the thermal or heating and coagulating effects.
The procedure is done simply on an outpatient basis. The head is positioned at a slit lamp, which the ophthalmologist will use routinely for eye examination. Using the aiming beam, we can then direct the YAG laser to the membrane that needs to be cut. The laser beam passes harmlessly into the eye, striking the secondary cataract where it will make a very precise and delicate opening in the membrane, allowing the light to pass through to the retina.
The procedure is painless and takes only a few minutes. Hospitalization is not required. The patient can normally see clearly in a few minutes and can resume normal activities immediately with no "post-operative' recuperation period. Vision will continue to improve in the days and weeks following the procedure, although more light should be entering the eye almost immediately after the procedure. In addition to treating secondary cataracts, the YAG laser can also be used for treating certain other ocular disorders, such as scar tissue, fibrous bands and glaucoma. It must again be emphasized that cataracts are not removed with this laser.
Before any surgical procedure, you should be familiar with the risk, complications and alternatives to surgery. Other questions you should ask are:
- What type of procedure will I need to have (i.e., is it the "small incision-microsurgical" procedure; will "ultrasound" be used)?
- What type of implant will I need to have (i.e., a "foldable lens" or one requiring a larger incision)?
- How many surgeries of this kind has my doctor performed?
- Will I incur additional expenses from the hospital or surgical facility, anesthesia, laboratory, etc.?
- Will I need any anesthesia?
- Will I need any sutures?
In summary, cataract surgery is a relatively safe way to restore vision to a person suffering from cataract disease.
One must pay careful attention to be sure that this is not associated with retina or macular disease, which will interfere with post-operative visual success. As with all surgery, it is important that the patient and family understand all risks, complications and alternatives to surgery, and then, along with informed consent given by their ophthalmologist, make an educated decision. One can feel confident when contemplating cataract surgery. This procedure is one of the safest surgical procedures being done today. The patient can anticipate the surgery with hope rather than fear.
