SIMPLE ALLERGIC CONJUNCTIVITIS
It is a mild, non-specific allergic conjunctivitis characterized by itching, hyperaemia and mild papillary response. Basically, it is an acute or subacute urticarial reaction.
Etiology
It is seen in following forms:
1. Hay fever conjunctivitis. It is commonly associated with hay fever (allergic rhinitis). The common allergens are pollens, grass and animal dandruff.
2. Seasonal allergic conjunctivitis (SAC). SAC is a response to seasonal allergens such as grass pollens. It is of very common occurrence.
3. Perennial allergic conjunctivitis (PAC) is a response to perennial allergens such as house
dust and mite. It is not so common.
Pathology
Pathological features of simple allergic conjunctivitis comprise vascular, cellular and conjunctival responses.
1. Vascular response is characterised by sudden and extreme vasodilation and increased
permeability of vessels leading to exudation.
2. Cellular response is in the form of conjunctival infiltration and exudation in the discharge of eosinophils, plasma cells and mast cells producing histamine and histamine-like substances.
3. Conjunctival response is in the form of boggy swelling of conjunctiva followed by increased connective tissue formation and mild papillary hyperplasia.
Clinical picture
Symptoms include intense itching and burning sensation in the eyes associated with watery
discharge and mild photophobia.
Signs.
(a) Hyperaemia and chemosis which give a swollen juicy appearance to the conjunctiva.
(b) Conjunctiva may also show mild papillary reaction.
(c) Oedema of lids.
Diagnosis
Diagnosis is made from :
(1) typical symptoms and signs;
(2) normal conjunctival flora; and
(3) presence of abundant eosinophils in the discharge.
Treatment
1. Elimination of allergens if possible.
2. Local palliative measures which provide immediate relief include:
i. Vasoconstrictors like adrenaline, ephedrine, and naphazoline.
ii. Sodium cromoglycate drops are very effective
in preventing recurrent atopic cases.
iii. Steroid eye drops should be avoided. However, these may be prescribed for short duration in severe and non-responsive patients.
3. Systemic antihistaminic drugs are useful in acute cases with marked itching.
4. Desensitization has been tried without much rewarding results. However, a trial may be given in recurrent cases.
OPTOMETRY-SHARP VISION
Optometrist