Yes, its spring – and with it allergy time once again – a time when eyes redden, become itchy and sore and water like a downpour of rain.
Dr. Colin Chan from the Vision Eye Institute says that up to 40 per cent of people in Australia suffer from allergies.
Furthermore, he says that while epidemiological data on allergic conjunctivitis is scarce, anecdotally and in his practice, there seems to be a higher incidence of new adult onset seasonal and perennial conjunctivitis.
No one knows the reasons why, but environmental changes both in the workplace and at home may be factors. For example, air conditioning and increased use of computer terminals in offices has increased the prevalence of dry eye; and a compromised ocular surface and tear flow system is certainly more susceptible to allergens.
Seasonal allergic conjunctivitis (SAC) is the most common form of eye allergy and typically precipitated by exposure to environmental allergens such as pollen and rye grass with airborne concentrations increasing in the spring. Perennial allergic conjunctivitis (PAC) is also very common, and usually triggered by animal dander, feathers and dust mites.
Dr. Chan says: “The typical symptoms of seasonal allergic conjunctivitis are itchy, red watery eyes and mucoid whitish discharge. The conjunctiva can also appear milky due to oedema. Associated rhinitis is common. Vision is unaffected.”
People with SAC may also complain of burning eyes, sensitivity to the light and blurred vision. The eyes usually look red and the eyelids can become swollen. When the inside of the eyelid (the conjunctiva) becomes swollen, the eyes can have a watery, gelatinous-like appearance – a finding called ‘chemosis’.
“Perennial allergic conjunctivitis has similar features but the symptoms are year round with seasonal exacerbations,” said Dr. Chan. “Chronic exposure to allergens such as dust mites, animal dander and mould spores are thought to be the precipitants in perennial allergic conjunctivitis. Again vision is unaffected.
“Vernal keratoconjunctivitis is uncommon and is a disorder of childhood and teenage years. It has a course of five to ten years, is more common in certain racial groups such as Asians and Africans and has some classical features such as giant papillae, Horner-Trantas dots and shield ulcers. Corneal ulceration can threaten vision. Again, seasonal exacerbations are common.”
Diagnosis
Allergic conjunctivitis can be diagnosed by reviewing a history of symptoms that suggest eye allergies and examination by a healthcare professional. Testing that indicates seasonal or perennial allergies is valuable and the patient’s response to typical medications is also useful in the ultimate diagnosis of allergic eye disease.
Seeking Relief
While sufferers of allergic conjunctivitis should try to avoid the triggers – be they seasonal or perennial – those who can not prevent allergic conjunctivitis may find some relief by applying cold compresses to the eyes and by using eyewashes with tear substitutes.
Medications can also be used to treat the symptoms.
Effective oral anti-histamines include over-the-counter loratadine (eg. Claritin and generic forms), and prescription cetirizine (eg. Zyrtec), fexofenadine (eg. Telfast and generic forms) and desloratadine (eg. Clarinex). Older, first-generation anti-histamines (such as Benadryl) are also helpful, but are generally considered too sedating for routine use.
Medicated eye drops are available in over-the-counter and prescription forms. However over-the-counter eye drops for allergic conjunctivitis are currently only available in decongestant (Visine, Naphcon, generic forms of naphazoline), and decongestant/anti-histamine combinations (Visine-A, Naphcon-A, generic forms of naphazoline/pheniramine).
While medications give symptomatic relief, overuse of decongestant eye drops (with or without anti-histamines) can lead to conjunctivitis medicamentosa, which is characterised as rebound eye redness/congestion and dependence on the eye drops. There is no association of prescription eye drops with conjunctivitis medicamentosa from prolonged use.
While people with heart or blood pressure problems should use decongestant eye drops with caution, those with glaucoma should avoid them altogether.
Avoidance is Best
To avoid eye allergies when pollen counts are high, sufferers should keep outdoor activities to a minimum. Closed doors and windows will help and an air conditioner can be useful for some sufferers. However, it’s important to keep in mind that allergens spread through the air, which means they can still circulate throughout the house via air conditioning filters. People with severe reactions to pollens are wise to avoid air conditioning during spring and autumn. Instead, they should consider purchasing a HEPA (high efficiency particulate air) filter. These filter systems are very effective at removing allergens from the air indoors.
For more handy hints on how to avoid allergies, visit www.medicinenet.com.
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