A cataract is present when the normally clear lens of the eye becomes cloudy. Vision through a cloudy lens is like looking through a foggy window. Clouded vision impairs eyesight by making it difficult to read and see your surroundings. Cataracts commonly affect distance vision and cause problems with glare. Clouding of the lens is a normal part of the aging process and most individuals above the age of 65 have some degree of clouding. Above the age of 75 a majority of individuals have cataracts significant enough to impair vision. Most cataracts develop gradually over time and don’t usually affect eyesight in the early stages but visual disturbances occur as the clouding progresses. In the early stages of cataract development, visual problems can be alleviated with stronger lighting and prescription eyeglasses. At some point when visual impairment can jeopardize normal lifestyle, surgery may be required. Cataract removal is one of the safest, most effective and most common surgical procedures.

Cataracts usually develop slowly and cause no pain. Initially the clouding may affect only a small part of the lens with little or no vision loss. As the cataract enlarges, it clouds more of the lens and vision becomes impaired when significantly less light reaches the retina of the eye. Symptoms of cataract include Clouded, blurred or dimmed vision, Sensitivity tolight and glare, Increasingly impaired night vision, Halos round lights, Need for brighter light for reading and other activities, Fading or yellowing of colours, Frequent changes in eyeglass or contact lens prescriptions and Double vision in a single eye. Individuals with catarct also have increased sensitivity to light with sunlight, lamps and headlights appearing too bright. Driving may become uncomfortable and dangerous with the uncomfortable glare and halos around lights. Individuals mayexperience eyestrain and blink frequently to clear vision. A cataract is not dangerous to the physical health of the eye unless on rare ocassions it becomes completely white known as hypermature (overripe) cataract. This condition may lead to inflammation, pain and headache and requires surgical removal.

With age, the lens of the eye becomes thicker, less flexible and less transparent. The lens is made mostly of water and protein fibres which are arranged in a precise manner making it clear. With age the composition of the lens changes and the structure of the protein fibres break down with some clumping together. Age related changes are not the only cause of cataracts as some individuals are born with cataracts while others develop them in childhood. A congenital cataract may be as a result of an expectant mother contracting Rubella (German Measles) during pregnancy or due to metabolic disorders in the infant.

A cataract may develop in one or both eyes and in most cases develop in both. When a cataract is due to injury or trauma, it develops in the affected eye. The lens of the eye, suspended by tiny ligaments (bands of tough tissue fibre), is located just behind the iris and pupil and is thicker in the middle and thinner near the edges. In normal eye function, light passes through the cornea and pupil to the lens. The lens focuses this light producing clear, sharp images on the retina (the light sensitive membrane lining the back internal wall of the eye that functions like a camera). As a cataract develops, the clouded lens scatters light which leads to blurred image transmission to the retina. The lens is made up of 3 layers namely the thin outer capsule, the soft cortex and the hard centre known as the nucleus and a cataract may form in any one of these layers. There are 3 types of cataracts. The Nuclear Cataract is located in the centre of the lens. In the early stages individuals may become more nearsighted and may experience temporary visual improvement. This takes a turn for the worse when the lens turns more densely yellow and further clouds vision. The cataract may even turn brown as it progresses further impairing vision and colour perception. A Cortical Cataract appears as whitish wedge-shaped opacities or streaks on the outer edge of the lens cortex.

As it progresses, the streaks extend to the centre of the lens affecting light as it passes through. A subcapsular Cataract starts as a small opaque area just beneath the capsule of the lens. It usually forms in the back of the lens in the path light passes through to the retina. This kind of cataract may occur in both eyes but is usually more advanced in one eye.

Advanced age is the single greatest risk factor for the development of cataracts. Other factors that increase the risk of developing cataracts include Family history, Diabetes, Previous eye injury or inflammation, Previous eye surgery, Prolonged corticosteroid use, Smoking, Exposure to ionizing radiation and Excessive exposure to sunlight. An eye specialist can detect cataract development during routine eye examinations. Eyes should be examined every 2 to 4 years until the age of 65 and thereafter, every 1 to 2 years. An eye specialist should also be seen whenever eye problems develop. Tests commonly performed include Visual Acuity, Slit Lamp Examination where the anterior structures of the eye are visualised under magnification and Retinal Examination with the use of a slit lamp or Ophthalmoscope. The presence of a cataract requires treatment. If other eye conditions that limit vision such as advanced glaucoma or macular degeneration are present, cataract removal may not improve vision. The only effective treatment for cataracts is surgery to remove the affected lens. A Clear lens implant is usually performed to replace the affected lens at the time of surgery. If areplacement lens is not implanted, corrective glasses or contact lenses may be prescribed for vision. Cataracts can’t be treated with medications, dietary supplements, optical devices or excercise.