Endocrinology

What Are Cataracts? What Causes Cataracts?

Cataracts are cloudy areas in the lens inside the eye - which is normally clear. Cataracts can develop in one or both eyes. If they develop in both eyes, one will be more severely affected than the other. A normally clear lens allows light to pass through to the back of the eye, so that the patient can see well-defined images. If a part of the lens becomes opaque light does not pass through easily and the patient"s vision becomes blurry - like looking through cloudy water or a fogged-up window. The more opaque (cloudier) the lens becomes, the worse the person"s vision will be. According to Medilexicon"s medical dictionary, cataract is "Complete or partial opacity of the ocular lens.". There are two types of cataracts: *Age related cataracts - they appear later in life; the most common form. *Congenital cataracts (childhood cataracts) - these may be present when the baby is born, or shortly after birth. Cataracts may also be diagnosed in older babies and children - these are sometimes referred to as developmental, infantile or juvenile cataracts. Researchers from the University Zurich were the first to identify the chromosomal location and exact molecular defect in the coding region of the gene responsible for a childhood cataract. The rest of this article focuses just on age-related cataracts. A patient with cataracts will eventually find it hard to read, or drive a car - especially during the night. Even seeing people"s facial expressions becomes difficult. Cataracts are not usually painful. The patient"s long-distance vision is more severely affected at first. Articles About Eye Diseases What Is AMD? What Is Macular Degeneration? What Is Glaucoma? What Causes Glaucoma? As cataracts develop very slowly most people do not know they have them at first. However, the clouding progresses and vision will gradually get worse. Stronger lighting and eyeglasses can help improve vision. Nevertheless, eventually the vision impairment affects the patient"s ability to carry out everyday tasks. At this point the individual will need surgery. Fortunately, cataract surgery is usually a very effective and safe procedure. Cataracts cause more vision problems globally than any other eye condition or disease - especially in developing countries, where they are much more common among poor people, according to a study carried out in Kenya, The Philippines, and Bangladesh. Visit our specialized news section Eye Health / Blindness News Includes the latest news and research on vision problems and eye disorders, visual pathways in the brain, areas surrounding the eye, age related macular degeneration (AMD), glaucoma, cataracts, and much more. Add this Eye Health rss news feed to your rss reader Some studies indicate that cataracts are more common among elderly people further down the socioeconomic ladder in the USA - prevalence of cataracts causing significant visual problems appears high among older U.S. Hispanics who also often encounter barriers to access to care (in the USA "Hispanics" refers to Americans of Latin American origin, not people who originate from Spain). Both men and women are affected equally. According to the National Health Service (NHS), UK, approximately one third of people aged 65 or over have cataracts in one or both eyes. Factors that may increase the risk of developing cataracts We are all at risk of developing cataracts because we will all get old one day - the greatest risk factor is age. In the USA approximately 50% of people aged 65 or more have some degree of lens clouding. 70% of Americans aged 75 or more have their vision significantly impaired by cataracts. Researchers at the Wilmer Eye Institute at The Johns Hopkins Medical Institutions, Baltimore predicted that the number of people in the USA affected by cataracts is estimated to rise to 30.1 million people in the next 20 years, an increase of 50 percent, because people will live longer. The following factors may increase a person"s chances of developing cataracts: *Age *Close relatives who have/had cataracts (family history) *Diabetes *Ionizing radiation exposure - airline pilots have an increased risk of nuclear cataracts compared with non-pilots, and that risk is associated with cumulative exposure to cosmic radiation, scientists from the University of Iceland reported. The five-year incidence of nuclear cataract was 40% lower for statin users after adjusting for several factors, compared to non-statin users, another study found. *Long-term exposure to bright sunlight *Long-term use of corticosteroids - many people with asthma rely on inhaled, and sometimes oral, steroids, as do people with chronic obstructive pulmonary disease. A study conducted by the Centre for Vision Research, University of Sydney, Australia, revealed that cataract risk is higher for patients taking these medications. *Previous eye inflammation *Previous eye injury *Exposure to lead - lifetime lead exposure may increase the risk of developing cataracts, scientists from the National Institute of Environmental Health Sciences, USA revealed. *Crystallins loss of function - A specific type of protein (crystallins) begins to lose function as the eye ages. As the protein loses function, small peptides, made of 10 to 15 amino acids, start forming and accelerate cataract formation in the eye, a study revealed. What are the symptoms of age-related cataracts? Symptoms usually creep up many years after onset - usually when the person is elderly. Progressively, more of the lens becomes cloudy. People with mild cataracts will not notice they have it for a long time. Cataracts often affect both eyes, but rarely equally. People with cataracts may have the following symptoms: *Blurry, cloudy, or misty vision. *Some describe it as similar to looking through frosted glass. *Vision may be affected by small spots or dots. *The patient sees small patches which blur parts of his/her field of vision. *Vision gets worse when lights are dim. *Vision is sometimes worse when light is very bright (glare). *Some people with cataracts also comment that colors appear less clear and faded. *Reading becomes very difficult, and eventually impossible. *Glasses need to be changed more frequently. *Eventually wearing glasses becomes less effective. *In some rare cases patients can see a halo around bright objects, such as car headlights or street lights. *Double vision in one eye (rare). As the person"s vision deteriorates, and the glare of oncoming headlights and street lights gets worse, driving becomes awkward and potentially very dangerous - research carried out by optometrists and psychologists in Australia shows that motorists suffering from cataracts are less able to spot potentially dangerous hazards on the roads. Drivers with cataracts eventually start suffering from eyestrain and find themselves blinking more frequently in an attempt to clear their vision. Cataracts do not usually cause any change in the appearance of the eye. Any discomforts, such as irritation, aching, itching or redness are most likely caused by some other eye disorder. Cataracts are not hazardous to the sufferer"s health, or the health of the eye. If the cataract becomes hypermature (completely white), the sufferer may experience inflammation, headache and some pain. Hypermature cataracts need to be removed if there is inflammation or pain. How are cataracts diagnosed? Anybody who experiences vision problems should see a GP (general practitioner, primary care physician), an ophthalmologist, or an optometrist. The GP will most likely refer the patient to an ophthalmologist, or an optometrist. *Ophthalmologist - a doctor who specializes in the medical and surgical care of the eye. *Optometrist - a person practicing eye care, but does not perform surgery. The eye specialist will carry out a number of tests. These may include: *Visual acuity test - this tests how clearly the individual can see an object. It tests the person"s sharpness of vision. The patient reads letters from across a room. The two eyes are tested separately (one is covered). By using a chart with progressively smaller letters, the specialist can determine how acute the patient"s vision is. The chart is called a Snellen Eye Chart. Sometimes the chart has to be read twice - once with, and once without bright lights. This will give an indication of glare sensitivity. *Slit-lamp examination - this is a microscope which allows the specialist to see the structures at the front of the eye. An intense line of sight (a slit) is used to illuminate the cornea, iris, lens, as well as the space between the iris and the cornea. The slit makes it possible for the specialist to see these structures in small sections, making it easier to spot any problems. *Retinal examination - eye drops are administered which dilate the pupils, providing a bigger window to the back of the eyes. The specialist examines the lens for signs of cataract with either an ophthalmoscope or a slit lamp. If signs of cataract are found, the specialist can also determine how dense the clouding is. Most specialists will check for glaucoma at the same time, and perhaps some other eye conditions/diseases. The pupils will remain dilated for a few hours after the examination before the eye drops gradually lose their effect. During this time the patient may find it harder to focus on close objects. It is advisable to wear sunglasses, especially if it is a bright day. Driving is not advisable until the pupils are back to their normal size. *Measuring a protein related to cataract formation - A device based on a laser light technique called dynamic light scattering can safely eye test for measuring a protein related to cataract formation, according to researchers at the National Eye Institute, USA. Although an eye test may help confirm a cataract diagnosis, it may not always reflect the patient"s quality of life. Some patients who do badly in a test seem

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