In-vivo diagnostic measurements of ocular inflammation

The diagnosis of allergic conjunctival inflammation is usually made on the basis of clinical signs and symptoms; however, in-vivo and in-vitro tests are indicated when patient management requires identification of the specific allergic sensitization. The purpose of this review is to describe recent and less recent methods to assess ocular allergic inflammation.

In the non-active phase of the disease, the specific conjunctival provocation test can be used to identify local sensitivities to allergens. Although not highly specific, total IgE in tears may be measured with a simple local test by inserting a paper strip in the lower meniscus. Limited tear volume prohibits the use of specific IgE tests. The measurement of tear-specific inflammatory markers, such as eosinophil cationic protein, IL-4, IL-5 and eotaxin, may also be useful for the diagnosis of ocular allergy. Multiple cytokine assays of tear samples and new imaging techniques are exciting advances that might provide the in-vivo diagnosis of ocular surface inflammation.

Whereas chronic, severe ocular allergic conditions have uniquely diagnostic signs and symptoms, the most common diseases, seasonal and perennial allergic conjunctivitis, have no specific pathognomonic signs. The diagnostic measurements of local inflammation may help in the management of ocular allergy.