Ah…Spring! The sun is shining brightly; the birds are singing and reproducing and bees are pollinating the budding flora. It’s a time of renewal and joy…or is it? Certainly not for many people as it signals a season of itchy and weeping eyes. For much of the population, about four million of us, it’s a season of ocular allergies. Dr. Colin Chan from the Vision Eye Institute explains the suffering of eyes during Spring and the best way to treat the often debilitating condition.
Ocular allergy is a common problem. Up to 40 per cent of people in Australia suffer from allergies.1 Current epidemiological data on allergic conjunctivitis is scarce, but anecdotally and in my 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 possible factors. For example, air conditioning and increased computer terminal use in offices has increased the prevalence of dry eye and a compromised ocular surface and tear flow system is certainly more susceptible to allergens.
Allergic conjunctivitis causes significant distress leading to a significant reduction in quality of life and reduced work productivity, but because of its mild ocular consequences it’s perhaps not as rigorously treated as other ocular conditions.2
Types of Ocular Allergy
Ocular allergy comes in four main forms:
Allergic Conjunctivitis causes significant distress leading to a significant reduction in quality of life and reduced work productivity, but because of its mild ocular consequences it’s perhaps not as rigorously teated as other ocular conditions
- Seasonal allergic conjunctivitis (SAC)
- Perennial allergic conjunctivitis
- Vernal keratoconjunctivitis
- Atopic keratoconjunctivitis
Seasonal allergic conjunctivitis is the most common form of ocular allergy. The typical symptoms are itchy, red watery eyes and mucoid whitish discharge.
The conjunctiva can also appear milky due to oedema (Figure 1). Associated rhinitis is common. Vision is unaffected. It typically is precipitated by exposure to environmental allergens such as pollen and rye grass with airborne concentrations increasing in the spring.
Perennial allergic conjunctivitis has similar features but the symptoms are year round with seasonal exacerbations. 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. It 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 (Figure 2). Corneal ulceration can threaten vision. Again, seasonal exacerbations are common.
Atopic keratoconjunctivitis is an uncommon severe ocular allergy which typically occurs in young to middle age adults. A hallmark is the presence of atopic dermatitis. It is a lifelong chronic condition which leads to severe ocular complications including corneal ulcerations, corneal neovasularization, cataract and conjunctival scarring (Figure 3).
Diagnosis of Allergic Conjunctivitis
Seasonal and perennial allergic conjunctivitis are sometimes difficult to differentiate from dry eye or chronic conjunctivitis. Signs are rarely classical. A high index of suspicion and careful questioning will usually lead to the diagnosis.
The following clues will point towards ocular allergy:
- Itchy rather than dry or scratchy eyes
- History of atopy: hayfever, eczema, asthma
- Seasonal symptoms or seasonal exacerbations
- Well defined precipitants e.g. animal dander
- Stringy white mucoid discharge
Treatment
A plan for treatment should be tailored according to the severity of symptoms (Table 1). Topical antihistamines and ‘dual action agents’ (combination antihistamines and mast cell stabilisers) are the mainstay of treatment. Dual action agents in particular act on multiple key areas of the allergy cycle.
These should be initiated early as allergy becomes harder to control with time due to the self-perpetuating nature of the allergy cycle i.e. mast cell degranulation leads to further inflammation which leads to further degranulation. Vasoconstrictor agents should be avoided as they mask symptoms rather than treat underlying pathology and rebound symptoms may occur after cessation.
Pre-dosing with mast cell stabilisers in the weeks leading up to spring may also be a good strategy for patients whom experience more severe or more recurrent attacks. It is also important to educate the patient to recognise the symptoms and to self-initiate treatment early to avert more severe attacks. Often a handwritten action plan is very useful and helps avoid recurrent presentations. Another clinical caveat is that clinical response to mast cell stabilisers varies greatly and different agents within this class should be tried to determine which has the optimum effect. Response time can also vary and a trial for at least three days is recommended.
|
Symptons |
Treatment |
| VERY MILD |
|
| MILD |
|
| MODERATE |
|
| SEVERE |
|
Dr. Colin Chan is an ophthalmic surgeon at Vision Eye Institute, Bondi Junction and Chatswood, specialising in cornea and refractive surgery and is a Senior Visiting Fellow at the School of Optometry, University of New South Wales.
References:
1. Worldwide variation in prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema: ISAAC. The International Study of Asthma and Allergies in Childhood (ISAAC) Steering Committee. Lancet 1998; 351:1225-32.
2. Pitt AD, Smith AF, Lindsell L et al. Economic and quality-of-life impact of seasonal allergic conjunctivitis in Oxfordshire. Ophthalmic Epidemiol. 2004 Feb;11(1):17-33
3. Wong AH, Barg SS, Leung AK. Seasonal and perennial allergic conjunctivitis. Recent Pat Inflamm Allergy Drug Discov. 2009; 3(2):118-27.
