Eye Conditions
The consequences of poor eye health, leading to the loss of vision are obviously quite dramatic and distressing for all people who develop eye conditions. Eye problems are represented by changes in vision and the appearance of the eye, or an abnormal sensation felt within the eye. Many conditions of the eye are localised problems, but many also incorporate and implicate other areas of the body. For example, changes in vision may indicate a higher-order problem in the brain. Eye conditions can also arise due to other co-occurring illnesses which put strain on the biological activity of the eye, such as diabetes and high blood pressure. People with diabetes are at a higher risk for eye diseases, including diabetic retinopathy, glaucoma, and cataract. Poor nutrition is by far the most substantial preventable risk factor in developing eye conditions, as many of the structures of the eye require specific nutrients to be taken up in the diet or by supplementation. Obesity is also associated with an increased risk of macular degeneration, diabetes causing diabetic retinopathies, and cataracts. Eye exercises and other physical exercise are also beneficial to overall health and for the health of our eyes. It is recommended to have regular eye exams through dilated pupils every two years, especially if you are in a higher risk group. Some common eye conditions causing people to suffer pain, discomfort and visual loss consist of identifiable symptoms as discussed below.
Eye Fatigue
Eye fatigue is a condition that results from the eye essentially performing a largely unnatural act. Prolonged focusing on a specific item causes ocular muscle stress and can lead to headaches. In a society rapidly dependent on the use of computers and other visual items from childhood, eye fatigue is no longer limited to elderly people. Tiredness, burning eyes and eye strain are all associated with eye fatigue.
Light Hypersensitivity
On emerging from indoors into a sunny day, intense levels of light can cause considerable discomfort to our eyes often causing pain behind the eye. Although this is not abnormal, many people are more susceptible to this irritation. Unfortunately, some pain medication can cause dilation of the pupils, inducing light hypersensitivity. Most noticeable in people susceptible to migraine, severe discomfort can result from bright light. Other eye disorders can produce light hypersensitivity such as eye injuries, inflammatory or infective eye problems of the front part of the eye, and corneal disorders. Light sensitivity has also been associated in patients with meningitis.
Night Blindness
Difficulty seeing in low levels of light, or poor night vision, is called night blindness. Older people frequently suffer from this condition, however others may not realise their night vision has decreased. Night blindness can occur for various reasons but most commonly from a cataract. Retinal degeneration, such as retinitis pigmentosa, is also associated with poor night vision. The pigment rhodopsin, present in the photoreceptors of the retina, is important in adjusting to differential levels of light. Elderly people have diminished levels of rhodopsin, and their eyes dilate slowly taking longer to adjust to low light.
Dry Eyes
Excessive dryness of the conjunctiva and cornea of the eyes can cause considerable eye discomfort. Dry eyes are characterised by a deficiency of water in the tear ducts and/or deficiency in other fluids protecting the eye (such as sebum or mucin). Dryness of the eyes can be caused by a variety of conditions including inadequate tear production and accelerated tear evaporation, vitamin A deficiency and refractive eye surgery. Sjögren's syndrome is also correspondent with dry eyes, where white blood cells attack the fluid secreting glands. Dry eyes may also be a result of aging.
Conjunctivitis
The conjunctiva is the thin transparent layer of tissue lying over the eye, which secretes fluids to maintain eye lubrication. Inflammation of the conjunctiva of the eye can occur, called conjunctivitis. Commonly, conjunctivitis is caused by a bacterial or viral infection causing localised inflammation. Although not a serious condition, conjunctivitis can cause considerable discomfort. It is characterised by red, sore, sticky eyes.
Macular Degeneration
Macular degeneration is a common condition in society causing many visual disturbances, representing a large percentage of all eye problems. It is characterised by the degeneration of the macula area attributed by the loss of photoreceptors central to the retina of the eye. Most commonly, macular degeneration occurs in elderly people, and may represent a form of atherosclerosis in the eyes. The central field of vision is primarily disrupted and this can spread, causing deficits in peripheral vision as well. Macula degeneration is associated with blurred and distorted vision, causing straight lines to appear curvy. Age is the biggest risk factor for macular degeneration, however other risk factors include being female, white, a smoker, and/or having a family history of the condition can also increase your susceptibility to the condition.
Retinal Pigmentosa
Retinal pigmentosa is a genetic disorder affecting a small percentage of the population. Like macular degeneration, retinal pigmentosa is an eye condition involving the progressive loss of photoreceptors. Night blindness is an early symptom of the condition as the peripheral photoreceptors, responsible for peripheral and night vision, are initially affected. The condition is usually diagnosed in early adulthood and total blindness occurs roughly around the age of 40.
Cataracts
When the normally transparent lens becomes cloudy and progressively opaque, a cataract has formed. This causes a dramatic reduction in the amount of light being captured by the retina. It is one of the leading causes of blindness worldwide and represents a considerable health problem in society. Under suboptimal conditions, the proteins of the lens structurally change causing them to turn opaque (similarly what happens to the protein when an egg is cooked). The development of cataracts is related to aging, sunlight exposure, smoking, poor nutrition, eye trauma, systemic diseases, genetic family history, and certain medications such as steroids. There is a high prevalence of cataract amongst developing countries as poor nutrition heavily impacts on the development of cataracts.
The Appearance of a Cataract (Source: www.eyemdlink.com)
Glaucoma
Glaucoma occurs when the optic nerve at the rear of the eye becomes progressively damaged leading to blindness. Symptoms occur long after the progression of the condition making it difficult for early detection. Most commonly, this occurs due to increased pressure in the eyes. The structural integrity of the blood vessels within the eye influences its overall function and health. Malfunctioning blood vessels can cause leakage (known as oedema) into the surrounding tissue causing damage and increased pressure within the eye. Alternatively, glaucoma can result from poor and diminished blood supply to the optic nerve, or may be due to structural deficits in the nerve itself. An increased risk of glaucoma can result from increasing age (above 60), diabetes, high blood pressure, migraine and genetic family history.
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