The eye’s lens is a normally transparent structure that sits behind the iris and works in a manner similar to the lens of a camera. Together with the cornea, it helps to refract (bend) and focus light rays onto the retina. Nerve cells in the retina then transform the light into electrical impulses, which travel to the brain via the optic nerve and produce an image. The lens can change shape to adjust the eye’s focus on near and far objects.
A cataract is a clouding of the lens, which affects a person’s ability to see, and is a leading cause of blindness around the world. Most cataracts develop in older people, but this is not always the case. Some people may also be born with a cataract (known as a congenital cataract).
Risk factors include family history, prolonged exposure to sunlight, diabetes, hypertension, obesity, smoking, alcohol consumption, prolonged use of corticosteroids, statin medications (for high cholesterol), previous eye injury or eye surgery, hormone replacement therapy and a high degree of myopia (short-sightedness).
Cataracts are not painful and vision may not be affected during the early stages. However, this changes as the cataract advances and signs may include:
Early diagnosis and treatment of cataracts is the key to preventing vision loss. Advanced cataracts are usually obvious and easy to diagnose. However, early cataracts can be a bit harder. If your GP or optometrist diagnoses (or suspects) a cataract, he/she will refer you to an ophthalmologist for further investigation and management.
In the early stages, a stronger glasses or contact lens prescription may be adequate. When this is no longer the case and your ability to function on a daily basis is affected, then it could be time to consider surgery.
Cataract surgery involves removing the affected lens under local anaesthesia and replacing it with a clear artificial lens (known as an intraocular lens or IOL). The IOL cannot be felt once placed inside the eye. The operation itself takes less than thirty minutes and can be performed in a day surgery or in hospital.
Cataract surgery is actually the most frequently performed surgical procedure around the world. With laser cataract surgery, a femtosecond laser is used to complete several steps that the ophthalmic surgeon would normally perform manually. Studies support the benefits of using laser cataract surgery where possible, but it is important to understand that both laser-assisted and conventional cataract surgery are highly successful and safe procedures.
IOLs have evolved over time and there are now various options available to correct pre-existing refractive errors (e.g. short-sightedness, long-sightedness or astigmatism). Similar to the lenses in glasses, IOLs are manufactured to meet a certain prescription. Glasses may still be required for certain activities following surgery and this depends in part on the type of IOL chosen.
Monofocal lenses produce clear vision at a single distance (either near/reading or far), in contrast to multifocal IOLs which allow corrected vision at both near and far distances. However, the very latest in IOL technology is the arrival of trifocal lenses – these lenses provide clear vision at near-, mid- and far distances, thereby eliminating the need for glasses altogether. Your ophthalmologist will discuss the advantages and disadvantages of each IOL option and help you select the one best suited to your situation.
Once the affected lens is replaced, it is not possible to develop another cataract. However, a further procedure may sometimes be recommended to achieve even clearer vision.
Vision Eye Institute has a number of ophthalmologists who specialise in the diagnosis and treatment of cataracts, including laser surgery. Click here to find your nearest cataract clinic.
Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.