Eye allergies – and fast remedies

Summer time – hay fever time! A few days of spring sunshine, and most of us begin to look forward to the lazy, hazy days of summer. Many people, however, have other things on their minds: the dreaded allergies that cause red, itchy, watering or even swollen eyes. And for spectacle or contact lens wearers, the problem is even worse. The culprit: pollen. Many of our organs can be affected by allergic reactions, but it's definitely the eyes that suffer most. BETTER VISION looks at the causes and treatment of eye allergies – and at the available remedies to alleviate acute symptoms.

If our bodies come into contact with substances that are alien to them or could pose a potential danger to them, they trigger a defence process. One of these substances is allergens. These are primarily tiny proteins that, generally speaking, do not constitute a threat to the organism.

However, people with allergies develop special antibodies which lead to the release of various tissue hormones in our skin and mucous membranes. The most important of these hormones with regard to allergic symptoms is histamine: it is responsible for many of the body's allergic reactions, e.g. itching, shortness of breath or increased dilation of blood vessels.

The immune system is activated the first time the body experiences the allergen. This process then occurs every time a new contact takes place. This means: if the body has reacted allergically to a substance once, it never forgets. In other words, repeated contact with the substance leads very quickly to an allergic reaction – usually in a matter of minutes, but it can sometimes take up to one hour.

The reaction of the eyes is particularly severe; the conjunctiva and mucous membrane react immediately to the foreign substance, the blood vessels dilate and fluid is released. We experience this in the form of tears, a runny nose, swelling or reddening. The tears gradually flush the allergens out of the eyes, therefore slowly alleviating the symptoms.

During the hay fever season spectacles offer additional protection to your distressed eyes – regardless of whether they are sunglasses or your normal prescription spectacles. Wrap models and frames with broad sides are ideal for allergy sufferers. These protect sensitive eyes against bright light, draughts and partly also against pollen floating around in the air.

Depending on the season of the year, it is usually pollen that causes the most problems. However, there are many other factors that can irritate the conjunctiva of our eyes: animal hairs, dust mites, fungal spores, insect poisons or intolerance to certain types of food, e.g. glutamate. It is essential for the sufferer to find out what exactly is causing his or her allergy. Various tests which can be performed by dermatologists or allergy specialists are available for this purpose. One example is the prick test which is primarily used to detect a pollen allergy: droplets containing various types of pollen are applied and then scratched into the skin. Don't worry: this does not cause scars. After around 20 minutes the doctor can tell from the reaction of the skin whether an allergy is present and, if it is, to what, and then develop the appropriate therapy.

The plaster test is used primarily to detect contact allergies. Here, several plasters are adhered to the patient's back. They contain the substances that are assumed to be the culprits triggering the allergy. The plasters are normally worn for a period of 24 to 48 hours and the show the doctor at a single glance to what substances the skin is allergic.

Yes, either via a long-term therapy (desensitization) comprising the use of mast cell stabilisers, or via medication known as H1 blockers. If the cause of the eye allergy is known, a specific immune therapy, also known as hypo- or desensitization, helps in 70 percent of cases. Here, the substance to which the sufferer is allergic is repeatedly administered in a highly diluted form for a period of six months to three years. In this way, the body gradually "accepts" the allergen without displaying defence reactions.

If the patient does not respond to this type of therapy, special anti-allergic medication in the form of eye drops or a nose spray may be an effective alternative. The drug stabilises the mast cells so that the histamines which they contain are not released. The allergic reaction does not then occur at all, or only to a very minimal extent. The medication must be taken regularly and at the right time. However, it has a prophylactic function only and does not alleviate acute symptoms. It is taken several times a day two to three weeks before the pollen season begins. This type of medication is normally available over the counter.

If the symptoms are acute or severe, e.g. severe itching, highly selective H1 blockers are the medication of choice. They modify the permeability of blood vessels in the conjunctiva for anti-inflammatory substances, block the histamine receptors and therefore prevent the inflammatory histamine reaction. Eye drops containing this substance are only available on prescription.

Soft contact lens wearers are at a particular disadvantage if they suffer from hay fever. Although anti-allergic eye drops are excellent to alleviate the symptoms of hay fever, they are not usually very well tolerated by soft contact lenses as these display larger pores than hard contact lenses. The eye drops are deposited in these pores and dissolve parts of the contact lens material, leading to additional irritation of the conjunctiva and cornea. A good alternative for soft contact lens wearers suffering from hay fever is sunglasses with wrap frames or daily disposable contact lenses ("dailies"). These are always taken straight from the packaging, therefore preventing any deposition of pollen.