Normal working of the eye

Before understanding cataract, it is important to know how a normal eye works. The eye is like a camera. The lens in a camera allows light to pass through and focuses that light on the film at the back of the camera for a clear picture.

The eye works in a similar way. The lens of the eye is normally clear and allows light to pass through. The light is focused on a thin film-like retina, which is situated at the back part of the eye. This is how we see.

• What is a cataract ? There is a normal clear crystalline lens in the human eye. Cataract is the cloudiness of the normally clear lens in the eye. It prevents the lens from focusing light onto the retina and hence causes unclear vision. As the cataract advances, this cloudiness of vision increases over a period of time until the vision is completely impaired.

• Why does a cataract develop ? Cataract development is part of the normal ageing process. Most people above the age of 60 years have cataract of a variable degree, although it can occur at an earlier age also. Factors that can cause or aggravate cataract formation are eye injury, diabetes mellitus, use of steroids and other eye diseases. Rarely cataract may be present in the newborn as a developmental defect.

• What are the symptoms of a developing cataract ? Because cataracts form in different ways, the symptoms of cataracts are variable. Most people notice that their vision gradually deteriorates - objects may begin to look yellow, hazy, blurred or distorted. Many people also find that they need more light to see clearly, or that they experience glare or haloes from lights at night.

Till date there is no medical treatment for the prevention and cure for cataract. The only known treatment for cataract is surgery.

• When can one undergo Cataract Surgery ? Cataract surgery can be performed as soon as the patient feels handicapped in performing routine activities at work and leisure. With modern microsurgical techniques of stitch-less cataract surgery (phacoemulsification) it is not necessary to wait for the cataract to mature. In fact waiting for cataract to mature increases the risks of intraoperative complications.

• Are there any problems with an Intraocular Lens (IOL) ? Recent advances in IOL manufacture and surgery have made cataract surgery and IOL implantations very safe. Complications are rare and similar ones can occur with conventional surgery without an IOL implantation. All patients irrespective of other general illnesses like diabetes, hypertension etc. can have IOL surgery.

• Does one need glasses after IOL surgery ? The improvement in quality of life after cataract surgery is extraordinary, and most patients are not dependent on their distance glasses for daily activities. Some patients however, may need glasses of small plus or minus power to obtain the best possible distance vision. In most case when a monofocal intraocular lens is implanted glasses are needed for near work.

• What are the latest advances in Intraocular Lens (IOL) technology ? Advances in IOL technology have made available various state-of-the-art IOLs. These new lens designs include 1) Blue-light blocking IOLs that filter out harmful ultraviolet radiation as well as blue light, 2) Aberration-free IOLs which greatly improves image quality by enhancing contrast, eliminating glare and haloes, and improving night vision, and 3) the newer Multifocal IOLs which provides good unaided distance and near vision with less dependence on glasses. 4) Toric IOLs are also available for the correction of high cylindrical spectacle numbers. Depending on the patients' personal visual needs, the surgeon decides the most appropriate lens to implant in the eye.

• Is clear vision guaranteed after surgery ? Almost all the patients regain good vision following cataract surgery. There can never be a guarantee in any surgery performed on the human body, but the results of modern day cataract surgery are excellent.

The vision obtained after a successful cataract surgery with IOL depends upon the health of the retina behind. Other eye diseases in the cornea, retina or optic nerve may limit the potential for clear vision even when the cataract surgery itself has been successful.

However, it might not be possible to evaluate the condition of the retina, optic nerve, in advanced cataracts.

Cataract and IOL surgery is not a magical procedure and need not necessarily restore normal vision immediately. Blurred vision may be present immediately after surgery. As the eye heals over a period of time, vision improves gradually.

• What are the possible complications that can occur with Cataract & IOL surgery ? Modern microsurgical techniques for cataract removal are highly successful procedures. The few complications that exist are becoming even more remote, with newer developments in surgical techniques and anesthesia.

Some minor complications that can occur include a slight drooping of the eyelid, swelling around the eye, corneal haze, reflections or slight distortion from the lens implant, which are usually temporary. The chances for serious complications are negligible. Possible serious complications include infection, severe inflammation, and hemorrhage.

In a majority of cases these complications can be treated successfully or may resolve on their own with a good final restoration of vision.

• Do I have to get admitted for a cataract surgery ? Modern day cataract surgery is a day care surgery. The procedure is a day care procedure and the patient is discharged immediately after the surgery. One needs to wear protective goggles for at least a week and can resume all activities from 4-7 days after the surgery.