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CATARACTS
Cataracts or a clouding of the natural focusing lens of the eye is the most
common cause of blindness in the world. Most industrialized countries are able
to provide treatment for blindness caused by cataracts but there remain millions
of people worldwide who do not have access at present to modern cataract
surgical techniques. The lens of the eye, located behind the colored iris and
pupil is normally clear and capable of changing shape to alter focus from
distance to near. With age or other causes the lens becomes clouded and images
focused on the retina in the back of the eye become blurred. Also with age the
lens becomes less capable of adjusting its shape to focus at different
distances. People who once were able to see clearly at distance and at near find
that as they become older their near or reading vision decreases and they need
assistance with the aid of reading glasses.
How are cataracts
managed?
 | TREATMENT
The majority of cataracts are managed by surgery. This entails removal
of the natural lens by various techniques, intracapsular or extracapsular or
phacoemulsification using ultrasound waves. Many patients have read in the
lay press of the use of lasers to remove the cataract . In up to 50% of
patients undergoing cataract surgery, a clouding of the capsule that is left
behind after the initial surgery is removed with the laser. This is painless
and performed in the office. No one in the world is using laser as a primary
method of removing cataracts. Almost all patients have the lens replaced
with a man-made lens made of polymethylmethacrylate or silicone. Preoperatively
the eye is measured with painless ultrasound waves to determine the power of
the lens to be inserted. Within a certain amount of inherent error your
surgeon will be able to insert an appropriately powered lens to set your
vision for distance or near. Generally, most surgeons elect to set the
vision for distance and then have the patient use reading glasses for near
visual tasks. This varies between patient and should be discussed prior to
surgery. Almost all patients undergo the procedure as an outpatient and are
discharged within 3 hours. Medical problems such as severe heart disease,
diabetes and other diseases may require a short hospitalization before and
after the surgery. Only on rare occasions are patients placed under general
anesthesia. The use of a local anesthetic and intravenous sedation allows
for a painless procedure with almost immediate recovery. |
| INDICATIONS FOR CATARACT SURGERY
There are two major reasons to have cataract surgery performed.
Automobile licensing requirements Interference with activities of daily
living. |
| AUTOMOBILE LICENSING REQUIREMENTS
One of the most common reasons for undergoing cataract surgery is to
continue driving an automobile. Each province or state has minimal visual
standards that must be met to continue to safely operate a motor vehicle. If
vision begins to deteriorate from cataract surgery and begins to fall below
this visual threshold then the patient has two choices. First he or she may
consider to stop driving. This is usually not a common path to be followed
as many patients particularly those that are older, consider an automobile
essential to their sense of independence. The most commonly selected option
is to proceed with cataract extraction and lens implantation so that driving
may continue after recovery from the surgery. It is common practice to
perform the surgery when the vision is still good enough to drive but
showing signs of deterioration. By anticipating this fall in vision the
surgeon intends to correct one eye before the other so that the patient may
continue driving throughout this period. If the surgeon waits until the
vision is substandard then the patient's driver's license will need to be temporarily
revoked until visual recovery has been obtained. Patients need to understand
that in most jurisdictions a physician is required by law to revoke the license
of any individual that does not meet the minimum standard for driving. To
allow a patient to drive that has substandard vision not only puts the
community at risk but also creates an enormous liability for the physician
should the patient become involved in an accident. Patients who disagree
with a physicians revocation of their driver's license should contact their
local department of motor vehicles for clarification. |
| INTERFERENCE WITH ACTIVITIES OF DAILY LIVING
The interference of activities of daily living (ADL) assess on an
individual basis the visual demands of each patient. For example some
patients do not drive and therefore although their vision may be decreased
it still allows them to read large print books, watch TV, cook and play
cards. If however they find that they are not able to enjoy activities that
are a quality of life issue then certainly they should consider cataract
surgery. For example a patient interested in photography may have very high
visual demands that require surgery whereas the patient who enjoys hours of
TV and does not drive may be quite content with vision in the range of 20/60
to 20/100. |
| RISKS OF CATARACT SURGERY
As with any surgical procedure risks, though infrequent are an
inherent part of cataract surgery. With the development of modern cataract
techniques risks are greatly minimized from that of a decade ago. Still many
severe complications can occur that can lead to poor visual outcome or even
complete loss of vision or possibly even loss of the eye. Most surgeons
quote success rates of 20/40 vision or better in normal healthy patients in
95-97% of cases. Diseases such as diabetes can reduce postoperative visual
results and increase risk of complications. Your surgeon should be able to,
after taking an appropriate medical history and complete eye examination
estimate your risk for the procedure. Patients must always decide with
guidance from their surgeon whether the benefits of the surgery will
outweigh the risk, though infrequent of the procedure. Factors that increase
rate of complications
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| IDEAL CANDIDATE FOR CATARACT SURGERY
The ideal candidate for cataract surgery is one that has good general
health and whose sole cause of reduced visual acuity is due to clouding of
the native lens |
| GENERAL MEDICAL HEALTH
Over recent years we have been able to consider many more patients for
cataract surgery because of the increased utilization of local anesthesia.
Previously, many patients were denied surgery because of their inability to
tolerate a general anesthetic where the patient is put completely to sleep.
With the advent of improved intravenous techniques we can now offer surgery
to many more patients of poor health. In addition with the advent of
phacoemulsification and the utilization of a very small surgical wound into
the eye the procedure is much safer for the eye in patients with severe
respiratory disease. The self-sealing wound of the the phaco technique
greatly reduces the threat of loss of the contents of the eye. |
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