Cataracts are probably the most common cause of visual problems in the elderly. Not everyone is affected by it but in the UK alone, one out of three individuals will develop cataracts. That is a lot of people who can suffer from blurry vision or worse, go blind. Fortunately, these stained lenses can be extracted safely through cataract surgery.

The eye

The eye is a complex structure that allows people to see. The lens is responsible for focusing an image in order to have clear vision whether it is near or far. The lens consists mostly of water and clear protein fibres.

The eye is composed of two segments, the anterior segment and posterior segment. The anterior segment consists of a watery substance called the aqueous humour. Structures found in the anterior segment are the lens, iris, diaphragm, pupil, and the cornea. The posterior segment contains the gelatinous vitreous humour. Structures in this segment are the optic nerve and retina. Both the aqueous and vitreous humour contains nutrients that provide nourishment to the structures.

Formation of Cataracts

Amazingly, in spite of the advancements in medical studies and research, it is still unknown why the lenses change and form cataracts. There are a lot of factors that can lead to development of cataracts like overexposure to ultra violet light, smoking, poor diet, and high blood pressure but it has not yet been established why they occur. Other causes of cataracts especially in the young are injury to the eye, diabetes, or a family history of cataracts.

Types of Cataracts

There are three types of age-related cataracts and one or a combination of the three can occur at the same time.

Nuclear cataract - this is the most common form of cataract. As the name implies, the cataract forms at the centre portion or the nucleus of the lens. This is due to sclerosis of the lens or hardening of the lens due to ageing. As the cataract progresses, the lens loses its elasticity and is not able to stretch and contract when focusing especially near objects, making reading very difficult. Nuclear cataracts are very slow to progress and can take years before it can affect vision.

Cortical cataract - this type of cataract occurs at the cortex or the outer portion of the lens. This happens when there are changes in the water components of the protein fibres of the lens creating fissure-like structures that look very similar to spokes of a cart wheel. These opening fissures scatter light within the eye ball creating problems with vision, glare, and depth perception. Cortical cataracts are commonly found in diabetic patients.

Subcapsular Cataract - this type of cataract forms at the back of the lens. Also called posterior subcapsular cataract, this is a rapidly occurring cataract and symptoms can progress in just a few months. People who are using steroids or have high farsightedness, retinitis pigmentosa, and diabetes can develop this kind of cataract.

Treatment

The use of an operating microscope helped a lot in the advancement in cataract surgery. The instruments used are very small and made to precision to minimise trauma during the cataract operation.

The most popular method of cataract extraction to date is phacoemulsification. This eye surgery involves creating a punch incision into the side of the cornea. Then a special hollow tube is inserted into the cornea and placed directly over the lens. The tube emits ultrasonic sounds that break the lens into small fragments which are then sucked out at the same time. An intraocular lens is then inserted and placed behind the iris diaphragm. Phacoemulsification does not require any stitching since the incision is so small, it simply seals itself.

Cataracts today are easily treated with cataract surgery. The removal of the affected lens and replacing it with a new artificial lens not only gives the patient a clearer view, the errors of refraction are also corrected. This is a different kind of cataract operation and involves implanting a special kind of contact lens into the eye. The fact that the implanted lens corrects your vision is why it is known as refractive lens exchange.