Allergic conjunctivities in Clinical Optometry!

Optom
Wow its been  long time folks and friends. Sorry for the long absense. Thanks goodness, the world is a little bit better with such persons like Ghaddaffi, Sadam Hussain, Osama bin Laden etc gone... It is also heart warming to know that the referendum for South Sudan became a reality! The Arab spring is still spewing out more loosers e.g. in Yemen but life still goes on.
Without dwelling much on frivolities lets get blogging...
As the name implies, Allergic conjunctivities is a group of allergic conditions of the conjunctiva that is triggered when mast cells laden with IgE comes in contact with an allergen (antigen) and an antibody/antigen complex reaction is formed. Mast cell contains unreleased histmine. When a mast cell laden with IgE cross-links an antigen after been primed  by Beta-chemokines (a type of cytokines that actively involves in chemotaxis!) they (the mast cells) release histamine and a host other active intermediaries. These intermediaries are prostalglandin-G, Serotonin, leukotrienes, platlet activating factor and cytokines that further lead to priminig of more mast cells to repeat the circle. The T cells too play a role in the activation and degranulation process of mast cells. T cells contributes the specific IgE for a given mast cell. The release of these substances results in ocular itching, conjunctval and lid edema, formation of mucus (the string-like type of mucus common in allergic conjunctivitis).
In situations where the allergen becomes perennial, the cytokines in the viscious circle of mast cell degranulations will also attract Basophils and recruit tissue damaging body immune substances like T cells, macrophages, neutrophils & eosinopils. These immune substances form a complex pathway to the resulting tissue damage and deeper allergic reactions like papillae formations on the conjunctiva,sinusitis, rhinitis, tinitus etc
Apart from an allergen or injury causing degranulation of mast cells, it has been reported that a particular amount of stress can activate the mast cells even in the absense of IgE , especially those in the cerebrum! The complex mechanism, it is said, leads to mast cell reactions even in the absense of an allergen! (Theoharis C.T., David E.C. [2003]). Hypothetically it could explain why some refractive or binocular difficulties in the eye can trigger ocular itching!
From the foregoing discussion, it can be understood that allergic conjunctivitis is an immuno- sensitization degenerative condition of the outer 1/6 of the eye. It is very difficult to manage and usually it is self-limiting after a period of time. Lets discuss some ways to manage this condition.
First this condition causes vasodilation of conjunctival blood vessels. Histamine is responsible for this dilation of conjuntival blood vessels. One method to arrest this sign is by using steroids as vasoconstrictors. It is used as a short-term remedy. In the long run, it is important to combine it with an anti-histamine like gutt: spercellerg and/or tablets like tab: chlorophetamine while tappering the steroids. Anti-histamines tend to influence the effect of the elaborated histamines from the degranulated mast cells. Other class of drugs that could play an active role in combating this allergy includes Sodium cromoglycates, lodoxamide, nedocromil are known as mast cell stabilizers. They function by inhibiting the calcium ions that triggers the elaboration of histamine onto the tissue. They are the most effective therapy for this allergic condition. Other non medical mesures includes using cold compresses, wearing shades when outdoors and proper ventillation.
The main objective of treatment is the removal of the allergen which could be dust, smoke,pollen grains from flower, chemicals, paints, lots of exogenous substances that might come in contact with the eye. It should be put in mind to remove any form of refractive stress or binocular stress that might accompany the eye. Please ensure you discuss ocular hygiene with your patient.
Different types of allergic conjunctivitis will be discussed subsequently and specific measures to contain them will be enumerated. Thanks
Dr Ezebuiroh Victor Okwudiri.