Inside the eye is a lens, much like the lens of a camera. This lens focuses incoming light rays onto the retina - similar to the film of the camera. Ideally, the lens must remain transparent to allow the light to pass through it. But when it becomes opaque or cloudy, light is unable to pass through it. This causes the vision to become dim or get blurred. When a lens becomes cloudy, it is said to have developed cataract. As the cataract develops, it becomes harder for a person to see.
Cataract is not a new growth in the eye or a film over the eye. It is a cloudiness or opacity of the natural lens which occurs inside the eye. Cataract is usually white but can be tinted yellow or brown. White cataract is soft cataract. Yellow or brown cataract is hard cataract due to sclerosis or hardening process of the lens. When cataract first appears, the changes in the lens are mild so they are called "early cataracts". As these changes progress, they are called "Immature Cataracts". Once the cloudiness becomes pronounced enough to block most of the light entering the eye, they are called "Mature or Ripe Cataracts".
Causes of Cataracts :
Cataracts develop as a normal part of aging. Opacity of the lens is by enlarge a condition of old age. It develops in almost everyone sooner or later. About one half of all people between the age of 52 years and 64 years may have cataract. Occasionally, cataracts may be seen in younger age groups too.Congenital cataracts occurring in children need to be treated early or else a permanent vision suppression called amblyopia may occur. Also the weaker eye may get a squint.
Cataract occurring in old age is termed as Senile Cataract. Cataract occurring in newborns is called Congenital Cataract. Cataract occurring in young persons is termed Developmental Cataract. Cataract occurs due to injury or trauma to the eye. It may be a penetrating or a blunt injury. Here we call it a Traumatic Cataract. Cataract occurring due to other eye disease is called a Complicated Cataract. We have Irradiational Cataract due to exposure of the eye to welding and radiation as in Cancer treatment. Then we have Toxic Cataract due to toxins such as naphtheline ball consumption as in failed suicide cases.
Symptoms of Cataract :
Cataract is a condition which progresses over time. The most dense and mature the cataract becomes the more severe symptoms are.
The common symptoms are :
- Distance vision can be blurred especially outdoors, but without any eye pain.
- Double vision, seeing " ghost images ".
- Sensitive to glare, such as the reflection of light from metal on a car, road or fluorescent ceiling lights may cause glare.
- Print appears faded and lacking in contrast and is difficult to read in dim light.
- Colours appear faded or changed in hue, for example, blue may seem to be a shade of green or white colour as appearing yellowish brown.
Treating Cataract :
There are no proven medications, eye drops, diets or exercises that can cure or prevent cataract. Once the cataract interferes with the normal routine activities of the individual, the only solution is surgery to remove it.
When to have Surgery :
The best time for removing cataract depends on how the impairment of the vision handicaps the lifestyle of the person. Either local anaesthesia or eye drops are used to achieve anaesthesia. In most cases, the surgical cut is so small that the eye heals rapidly with little or no discomfort. In the surgery, the clouded natural lens is removed, leaving behind the lens capsule. Next, an artificial lens is inserted into the lens capsule of the eye.
Lens Implants :
After the natural lens is removed, it must be replaced by a substitute lens known as an intraocular lens implant( IOL ). More than 90% cataract surgeries taking place today involve implantation of the IOL. Before the operation, the eye surgeon conducts a test to determine the type and power of the IOL that best suits the individual.
New lens designs include the foldable lenses that are small enough to be inserted through small incision like 3 mm or less. Today there are a wide range of lens designs to suit every need of the patient.
Surgical Techniques :
There are two main surgical techniques that are used for removing cataracts :
- Phacoemulsification, and
- Extra capsular cataract extraction
1. Extra capsular cataract extraction surgery involves removal of the opacified lens after cutting the eye open upto 12-14 mm in size. Small incision sutureless cataract surgery is done for removal of cataract by extra-capsular cataract extraction.
2. Phacoemulsification : Simply known as " phaco " is the most advanced cataract removal technique. It can easily be performed through a very small incision, approximately 3 mm or smaller by advanced surgical machines like microsurgical system. A small needle delivers ultrasonic vibrations to fragment and remove the cataract. A foldable intraocular lens is then inserted through the same incision.
Road to Recovery :
With modern surgical techniques, one can get back to normal daily activities almost immediately. Getting the cataract operated upon has now become totally safe and convenient.