The eye and the lens
The crystalline lens in our eye is similar to the lens in a camera. It actively focuses images on the retina, the light sensitive film at the back of the eye. This lens must be transparent to produce a clear sharp image.
What is a cataract?
Cataract is the leading cause of vision loss among adults aged 60 plus. Statistics show that 90 percent of the population develop cataract by the time they turn 70. Even though it is easily treated, cataract still remains the leading cause of blindness in the world, and accounting for more than 2 million surgeries per year.
The origin of the word "cataract" is from the Greek word kataraktes, means that something is rushing or swooping down. Cataract's meaning is the progressive clouding or opacification of the crystalline lens in the eye. This lens in our eye is similar to the lens in a camera. It actively helps in focusing images on the retina, the light sensitive film at the back of the eye. This lens must be transparent to produce a clear sharp image. The causes and mechanism of cataract formation are not completely understood. But most common cataract is a sign of aging. The main causes of cataract are:
- Age related: Cataract incidence increases with age, and is more likely to be seen after 60 years
- Congenital: This is when cataract is present at birth
- Secondary: When cataract is linked to other conditions like diabetes, malnutrition and chronic eye disease
- Radiation: Sometimes after radiation exposure, a person may be affected by cataract.
- Traumatic: This is the result of an injury.
Do I have a cataract?
Cataracts can cause a variety of visual problems such as:
- Foggy or misty vision as if looking through a steamed window
- Difficulty in reading despite new glasses
- Glare in bright lights and sunlight, especially in urban built up areas
- Poor night vision particularly during driving
- Double or multiple images
- Difficulty in either differentiating or appreciating colours
- Frequent change in the power of spectacles
If you have any of the above symptoms, you might be developing a cataract. Your ophthalmologist will be able to confirm this.
How is it treated?
Cataract can be treated only through surgery, while spectacles may temporarily correct some of the visual difficulties caused by early cataract. Cataract surgery has excellent visual results
Over the years, there have been many methods of removing cataracts. Techniques have been evolving with new technology and instruments. Newer techniques include:
Phacoemulsification with Intraocular Lens Implant:
This is the most advanced technique with the maximum advantages. In this technique, the cataract is removed through an incision smaller than 3 mm, using an ultrasonic probe that gently breaks or emulsifies the cataract into tiny pieces which are then sucked out of the eye. The small wound required for this procedure has many advantages like:
- Painless & Bloodless procedure
- Faster Healing
- Minimal Post Operation care
- Faster visual recovery
- Intraocular Lens: An IOL is an artificial lens implanted after removing the cataract. The main job of the IOL is to focus light onto the back of the eye (or retina), just as a natural, healthy eye lens would. Modern intraocular lenses are foldable allowing them to be inserted into the eye through a small incision, which is self sealing and requires no sutures. The intraocular lens is inert and can remain in the eye permanently.
- Small Incision Cataract Surgery (SICS): In SICS the cataract is removed in one or more pieces through an incision of 6-8 mm length, which may or may not require sutures. After the emergence of Phacoemulsification, SICS has lost its popularity and is done in set ups where the technology is not at par.
Cataract surgery is usually done under local anaesthesia, as day care, requiring hospitalization for just a few hours. The local anaesthetic is administered by eye drops or blunt cannulas.
Will I require spectacles after surgery?
- Since the intraocular lens has a fixed focus, this is usually targeted for distance enabling clear distance vision without spectacles.
- Spectacle will be required, however, for all close work including reading. For those who are keen, options are available that will allow complete freedom from spectacles following cataract surgery. Your surgeon will tell you more.
When should I consider surgery?
- Cataract can be surgically removed. It is important to remove cataract early as it hardens with time, as they mature.
- Cataract surgery should be considered as soon as it interferes with one's daily activities. This would depend on one's occupation and hobbies. The decision regarding the timing of surgery is however in the hands of the treating doctor.
- Micro Incision Cataract Surgery (MICS): In this, the incision size is as small as 2mm, recovery is quicker.
- Multifocal IOL Implants: Multifocal IOLs are lens implants designed to reduce the dependency of spectacles to the minimum. With these lenses the patients can see near, mid & far distance clearly)
- Toric IOL Implants: Toric IOL is useful in cataract patients with high Astigmatism
- Day Care Surgery: With the newer techniques of cataract surgery, stay in hospital is reduced to a few hours.
Trivia 1: June is known as the Cataract Month
Myth Busters for Cataract (Click on myth to know the fact)
Fact: Cataracts are not substances and hence, cannot be dissolved with drops. Cataract formation is a natural part of the eye's aging process.
Fact: Cataract cannot spread from one eye to the other
Fact: The lens naturally clouds as it ages, making the process unavoidable. This progress can be slowed down by quitting smoking, alcohol, having a balanced diet, wearing sunglasses with proper protection (100 percent UVA & UVB protected) or a wide brimmed hat
Fact: Cataract is one of the safest surgical procedures in medical history, with a 95 percent success rate. There are risks which can be discussed with your ophthalmologist, before going ahead with the procedure.