The natural crystalline lens of our eye is clear which allows light to be focused clearly on the retina. With ageing, this lens loses its transparency and gradually becomes clouded thereby imparing vision.

Although most cataracts are related to aging, there are other types of cataract:

• Secondary cataract. Cataracts can form after surgery for other eye problems, such as glaucoma. Cataracts also can develop in people who have other health problems, such as diabetes. Cataracts are sometimes linked to steroid use.
• Traumatic cataract. Cataracts can develop after an eye injury, sometimes years later.
• Congenital cataract. Some babies are born with cataracts or develop them in childhood, often in both eyes. These cataracts may be so small that they do not affect vision. If they do, the lenses may need to be removed.
• Radiation cataract. Cataracts can develop after exposure to some types of radiation.

The risk of cataract increases with age. Other risk factors for cataract include:

• Certain diseases such as diabetes.
• Personal behavior such as smoking.
• The environment such as prolonged exposure to sunlight.

Cataract is characterized by a painless, progressive decline in vision. Apart from decreasing vision patients with cataract even in the early stages may experience increased glare while driving at night or reading in dim illumination, difficulty in differentiating objects at a distance and the need for frequent change of glasses.

Cataract is detected through a comprehensive eye examination Visual acuity test: The eye chart measures the vision for both distance and near vision. It quantifies the visual loss experienced by the patient.

Dilated eye examination: Drops are instilled in the eyes to widen or dilate the pupils. This allows detection and grading of the cataract. Moreover, the retina or the nerve of the eye is also examined for signs of damage or other eye problems. The effect of the dilating drops lasts for a couple of hours, during which time the patient may experience blurring of vision.

Cataract eye surgery can be performed at any stage once it starts interfering with the daily activities of the patient. With the advent of advanced techniques and technology, cataract surgery can be performed in a safe and effective manner even in the early stages and one need not wait for the cataract to mature. In fact more advanced and harder cataracts are associated with an increased incidence of complications.

Surgery is the only and definitive treatment modality for cataract.

The various options available are as follows:

1. Conventional Extracapsular Cataract Extraction (ECCE)

• Requires an incision of 10 – 12mm
• The cataractous lens is removed in a single piece
• A hard plastic intraocular lens is implanted
• Multiple stitches are required to close the wound
• Final glass prescription could take 6-10 weeks

2. Small incision cataract surgery

• Requires a smaller incision of 5mm
• Cataract is removed manually and lens is placed
• No stitches
• Faster wound healing

3. Micro incision cataract surgery, Over the years the size of the corneal incision made during cataract surgery has considerably reduced leading to faster visual recovery and reduced postoperative discomfort

• Requires a very small incision of about 2 mm
• The nucleus is emulsified into small pieces and removed
• A foldable lens is used allowing implantation into the eye without extension of the incision
• Walk-in walk-out procedure
• Painless, bloodless and stitch less surgery
• Can be done under topical anaesthesia

Types of intraocular lenses (IOL)

• Monofocal IOLA majority of intraocular lenses implanted are monofocal lenses. These lenses have the capability of focusing light from a single distance. Normally distant objects are clear and one requires glasses for reading. The monofocal lenses are either rigid non foldable or foldable. The foldable lenses can be inserted through a small wound allowing faster visual recovery and reduced postoperative discomfort.
• Toric IOLsIn certain situations, the patient may have a high cylinder or preoperative bend of the cornea. Monofocal lenses are unable to compensate for this, hence the patient requires glasses for distance vision postoperatively in addition to a reading power. Toric IOLs have the ability to correct the eye power both at the corneal and lenticular plane, thereby correcting the cylindrical power.
• Multifocal IOLsMultifocal lenses have different segments which focus light rays from various distances onto the retina. This affords a freedom of glasses for near, intermediate and distant vision to the patient.