At some time or another, everyone has had the experience of red, itchy, watery eyes, the feeling that there is something in the eye. Is this an allergy, an infection, a chronic eye condition or something else? Different eye conditions may have similar symptoms, but similar symptoms may have different causes. To add to the confusion, different eye conditions can coexist and overlap in ways that facilitate or worsen each other. Defining the distinguishing causes and features and making an accurate diagnosis will lead to appropriate treatment. EYE ALLERGIES An allergy is the overreaction of the body's disease-fighting immune system to something in the environment that typically causes no problem in most people. When the allergen comes into contact with the antibodies attached to the mast cells in the eyes, the cells respond by releasing histamine and other substances to defeat the irritants. The histamine stimulates the eye's blood flow, causing redness and watering as blood vessels dilate and leak. The histamine also stimulates the eye's many nerve endings resulting in itching. There are various types of eye allergies, the most common being seasonal allergic conjunctivitis, which, as the name implies, occurs at specific times of the year, typically spring, depending on the type of pollens in the air. Perennial allergic conjunctivitis occurs year-round and is generally a reaction to household allergens like dust mites or pet dander. Vernal keratoconjunctivitis is often associated with conditions such as asthma and eczema. While it can occur throughout the year, symptoms may worsen seasonally. Contact lens wearers may experience contact allergic conjunctivitis which results from irritation by the contact lenses or by the proteins from tears that bind to the surface of the lens. Pain in the eye or diminished vision are symptoms not typical for allergies. The symptoms of eye allergies include redness, itching, watering and burning. The eyelids may be puffy and there may be sensitivity to light. Seasonal conjunctivitis is usually present in both eyes and may be accompanied by sneezing and nasal congestion. While there is often a clear discharge with seasonal and perennial conjunctivitis, the discharge with vernal and contact allergic conjunctivitis is generally thicker. Blurred vision may be one of the symptoms of contact allergic conjunctivitis. Giant papillary conjunctivitis is a more severe form of contact allergic conjunctivitis, in which fluid sacs or papules form in the upper lining of the inner eyelid, leading to discomfort and intolerance of the contact lenses. Although not easy, seasonal and perennial conjunctivitis can be prevented or controlled to some extent by taking steps to avoid the allergic reaction triggers, such as keeping windows closed during high pollen periods and reducing exposure to dust mites. Over the counter eyedrops are commonly used for the relief of uncomfortable symptoms, but prolonged use of certain eyedrops may worsen the condition. Artificial tears, preferably preservative-free drops, can be used as often as needed to moisten and soothe the eyes. Antihistamine eyedrops, oral medications or prescription eyedrops or medications may be prescribed to manage allergies. In more severe cases, corticosteroid eyedrops are used to treat chronic allergy symptoms. EYE INFECTIONS Conjunctivitis, or pink eye, is a common eye infection in children caused by a bacteria or virus. The conjunctiva is a thin layer of tissue that covers the whites of the eyes and insides of the eyelids. When this becomes inflamed or infected the eyes appear red. Other symptoms of pink eye include itchiness, excessive tearing and a feeling of something in the eyes, but the telltale sign is a thick discharge from the eyes and crusting on the eyelids upon waking up. While over the counter eye drops may relieve allergic redness, they cannot relieve conjunctivitis. Cold compresses and artificial tears may help to soothe discomfort. Keratitis is inflammation or infection of the cornea, the clear outer layer on the coloured part of the eye. Improper contact lens care or wearing contact lenses for too long increases the risk of keratitis, but it can occur as a result of eye injury, a weakened immune system and certain eye diseases. Symptoms include redness and irritation of the eyes, eye pain, a feeling of something in the eye, sensitivity to light, blurred vision and discharge or watery eyes. Treatment of keratitis may require antibiotic or antiviral medication in the form of eye drops or tablets. A fairly common eye infection caused by a bacteria, a stye is an infection in the eyelid, usually in an eyelash follicle or one of the oil glands of the eyelid. It may appear on the eyelash line or just inside the edge of the eyelid. Symptoms include a red painful lump and soreness or scratchiness on the eyelid or eyelash area. Most styes will clear on their own with the use of a warm compress several times a day and gently massaging the nodule. |
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DRY EYE DISEASE Dry eye disease is a common condition that occurs when the tears are unable to provide adequate lubrication for the eyes. Tears can be inadequate and unstable for a number of reasons; for example, insufficient tears are produced, or the tears are of poor quality. This tear instability leads to inflammation and damage of the eye's surface. Certain situations may make dry eyes worse, such as on an aeroplane or after prolonged use of a computer. Symptoms usually affect both eyes and include stinging or burning, watering, eye fatigue, sensitivity to light, redness, a scratchy sensation, discomfort wearing contact lenses and difficulty with night driving. Treatment for dry eyes is aimed at easing the discomfort. It can include lifestyle changes and preservative-free artificial tears. When confronted by confusing, overlapping symptoms, it is always best to seek the help, expertise and experience of your optometrist. |