The cataract affects the vision with the clouding of the lens that can develop in either one or both the eyes. The lens of the eyes focuses the image on the retina which is then converted to nerve signals that are delivered to the brain. When the lens of the eyes becomes cloudy, the images appear blurred. Most of cataracts may develop over a period of time and don’t affect the vision, but it can eventually disturb the vision. Most common causes of the cataract are related to the normal ageing process that occurs in people aged 40 and 50, however, small cataracts do not affect the vision and mostly cause problems after the age of 60 years.
Causes
The lens of the eyes consists mainly of water and protein which are regulated in order to ensure clear lens and to enable the light to pass through. As people age, the protein in the lens may clump together and cloud parts of the lens. As the cataract progresses, it may continue to grow larger covering more parts of the lens thus affecting the vision. Most of the cataract may develop as the result of a natural ageing process or with the injury that affects the tissue of the eye’s lens. Individuals with various inherited disorders are at risk of developing cataracts and may also develop as the result of other eye problems or health conditions such as diabetes. Some of the risk of developing cataract includes smoking, alcohol consumption and prolonged exposure to sunlight.
Types of Cataracts
Nuclear cataracts develop in the center part of the lens and may initially cause more nearsightedness. As the cataract progresses, the yellowing or the browning of the lens can affect the individual’s ability to distinguish shades of colors.
Cortical cataracts may develop as whitish, wedge-shaped opacities that begin in the outer part of the lens cortex and progresses to the center.
Posterior subcapsular cataracts usually develop at the back of the lens and individuals who are diabetic or take high doses of steroid medications are at increased risk of developing this type of cataract.
Congenital cataracts occur with babies born with this condition or may develop during childhood. This type of cataract does not usually affect the vision, but when they do, the lens is removed.
Symptoms
Some of the common symptoms associated with the cataract include the blurry vision, poor night or low light vision, faded colors, double or multiple images, the vision of halo around lights, requiring brighter light for activities, sensitivity to bright light or glare and frequent changes in the prescription glasses.
Diagnosis
Cataract is detected through an eye examination that includes the visual acuity test which measures how well individuals are able to see from distance, dilated eye exam that uses eye drops to dilate the pupils in order to examine the retina and the optic nerve. The tonometry test measure the pressure within the eyes and other examinations can help in assessing the structure of the eye.
Treatment
The only effective treatment for cataract is the surgery which replaces eye lens with an artificial lens. However, the initial form of the cataract can be improved with anti-glare eyeglasses, brighter lighting and new eye glasses. Usually, surgery that is required for both the eyes will be performed separately, around one month apart. It is estimated that around 90% of the individuals who have cataract surgery have better vision.
References
https://nei.nih.gov/health/cataract/cataract_facts
http://www.aao.org/eye-health/diseases/cataracts-symptoms
http://www.mayoclinic.org/diseases-conditions/cataracts/symptoms-causes/dxc-20215129
http://www.allaboutvision.com/conditions/cataracts.htm