Cataract
Restoring Vision Through Lens Replacement
Cataract (also referred colloquially as “Motia-bind” or “Safed Motia”) is one of the most common eye disorder especially amongst the elderly. It refers to the clouding of the natural lens of the eye.
The lens of eye is similar to the lens of a camera and is responsible for giving us sharp focused image. If the lens is not clear, the patient can only see a foggy or glary image. In a normal eye, the lens is a clear bag of water and proteins. Cataract develops when the proteins starts to clump together resulting in clouding of the lens. Initially it may involve only a part of the lens which gradually progresses and spreads to involve the entire lens resulting in significant impairment of vision.
- Who can get Cataract?
- How do I know if I have cataract?
- When and how is Cataract treated?
Who?
The Answer to this question is "Anybody"
Anybody at any age can develop cataract though most commonly its seen above 40 years of age as part of aging process. It's infrequently seen in newborns (congenital cataract) or in children or young adults (usually due to injury to the eye). Other important causes of cataract in young people include use of some drugs such as steroids, inflammation of the eye (uveitis), hereditary causes and radiation exposure.
Symptoms
Vision in presence of cataract is like looking through dirty glass.
Symptoms of cataract usually develops gradually and mainly include:
- Blurred vision.
- Increasing difficulty with vision at night.
- Sensitivity to light and glare especially from headlights during night driving.
- Halos around lights.
- The need for brighter light for reading and other activities.
- Frequent changes in power of spectacles or contact lenses.
- Fading of colours.
Cataracts in most cases doesn't cause any change in the appearance of the eye or pain, redness, and watering. These changes only appear when the cataract becomes completely white in later stages, a condition known as an overripe or hypermature cataract. This very late stage of cataract is dangerous for eye and can affect the health of the eye. This may result in severe and permanent loss of vision and therefore requires urgent cataract treatment including surgery.
Treatment
Treatment of cataract is primarily surgery. But every person doesn't need it. In early stages of cataract, change in the power of spectacles can also help.
As the lens becomes more cloudy, vision gets more blurred affecting the day to day functioning of the person. At this stage surgery is the only option to improve vision.
More Questions and Answers
This is probably the most common question I have to answer as an eye surgeon. There are various myths associated with this aspect. The most common myth is that the cataract has to be mature for surgery. This comes from pre-IOL era more than 3 decades ago. In today's age, allowing cataract to become mature is nothing less than negligence.
Another myth is that cataract surgery can only be done during winter months. This is not correct and cataract can be operated any time of the year.
The final decision to operate has to be jointly taken by the eye doctor and the patient. There are mainly 2 reasons for undergoing cataract surgery. When the patient cannot see the outside world clearly or when the doctor cannot see the inside of the eye clearly:
- Since cataract rarely causes any long-term damage to the eye, surgery is considered only when significant visual symptoms develop. Since the visual needs differ from person to person, the decision to undergo surgery is mainly based on the visual handicap the patient is experiencing.
- In some case the doctor may prescribe cataract surgery not for visual gain but to allow the doctor to evaluate and treat retinal diseases. In these cases, the cataract blocks adequate visualization of the retina and hampers treatment of retinal diseases
The answer to this question was much easier till a few years ago when the choice was limited. The best technique miles ahead of others was 'phacoemulsification'. However with introduction of newer modifications such as FLACS, the answer now is not so straightforward. And that's why it deserves a separate article in itself. Here i'll just try to summarise it in short.
The basic idea of cataract surgery is lens replacement. And the best way to do it is with a smallest possible incision. And that's Phacoemulsification. It involves a very small (2-3 mm) incision through which the contents of dirty lens is sucked out. This is followed by implantation of a clear soft foldable artificial lens (IOL).
The alternative is Extracapsular cataract surgery (ECCE) where, a large incision is made (approx. 10 mm) and the contents of the dirty lens removed as a big chunk. It requires multiple sutures to close the wound which takes longer to heal. It is rarely used these days but can be helpful for very advanced cataracts or when facilites for phaco are not available.
The oldest technique is Intracapsular cataract surgery (ICCE) and requires an even larger wound than ECCE. The entire lens is removed as one piece and no IOL is implanted. It goes without saying that its hardly used these days but can be useful in special cases as in cases of significant eye trauma.
FLACS or Femtosecond Laser Assisted Cataract Surgery which is "marketed" as bladeless or robotic cataract surgery. Even though it was introduced (like all new technologies) with much fanfare, recent studies suggests that "its a variation of phacoemulfication with no significant benefits in routine cases and improved results in only a small set of cases" and that "it involves significant increase in cost and surgical time ".
For more detailed assessment go to my article on comparison of phaco and FLACS
The artificial lenses implanted inside the eye during cataract surgery are intended to remain permanently in place and require no maintenance or handling. They are neither felt by the patient nor noticed by others.
Foldable lenses are made of soft material and can be implanted in the eye through the small incision of phaco surgery. Rigid lenses require larger incision for implantation during surgery and are thus used only during ECCE or ICCE.
Choosing the correct IOL has lifelong implications and should be decided after adequate deliberation. This is also a longer topic and requires a separate article in itself. I'll just try to summarize the types of foldable IOLs here
Even though multiple materials have been and still being used to make IOLs, the current "gold standard" material is hydrophobic acrylic. A cheaper alternative is hydrophilic acrylic which is primarily found in cheaper lenses. Silicone lenses are now practically obsolete.
The lenses also vary according to the optics and includes monofocal, monofocal aspheric, toric, and multifocal IOLs:
- Monofocal Lens: These lenses are most commonly used these days and provide good quality vision for distant objects. However for near work the patient require reading glasses.
- Monofocal Aspheric Lens – These are the newer generation monofocal lenses which have an aspheric design to improve the quality of vision and contrast sensitivity in dim light conditions. Reading glasses are still required for near work.
- Toric Lens: Toric lenses are used to correct astigmatism (cylindrical power). These are not required for all cases and is only helpful for people who have greater than 1 Dioptre of cylindrical power.
- Multifocal Lens: Multifocal lens contains more than one power within the same IOL. This allows the patient to see at a variety of distances without any glasses.
The cataract surgery is done on a daycare basis and the patient is usually sent home within a few hours. There are no special preparations for the surgery except for few eye drops which will be prescribed by the eye surgeon for use before surgery.
Only one eye is operated at a time. There is no restriction on food before the surgery if the surgery is being planned under local anaesthesia. If the patient is taking medications for other diseases then these needs to be discussed with the doctor beforehand. Some of the common medications that can interfere with surgery include:
- Blood thinners.
- Anti prostate hypertrophy drugs.
The operated eye is generaly patched for a few hours after surgery after which the patient has to start using eye drops. These drops are used for 3-4 weeks after surgery. Mild discomfort, irritation, watering, itching is common after surgery which usually reduces within the first few days
Rubbing or pressing the eye has to be avoided. The patient should also avoid exposure of the operated eye to dirty water, cloth or hands to reduce the risk of infection. Most of the restrictions apply only for a week after which the patient can continue with normal daily routine.
There are no dietary restrictions and the patient can continue to perform light household chores or professional work immediately after the surgery. There are no restrictions on watching TV, using computers or reading if the patient is comfortable.
There are no well established proven means of preventing cataract. In diabetic patients tight blood-sugar control can delay the otherwise accelerated development of cataracts.
None of the vitamins, minerals, herbal extracts or other supplements have been scientifically proven to prevent cataract in any age group.
