Ocular manifestations are a common feature of immunologic diseases even though, paradoxically, the eye is also a site of immune privilege. The propensity for immunologic disease to affect the eye derives from a number of factors, including the highly vascular nature of the uvea, the tendency for immune complexes to be deposited in various ocular tissues, and the exposure of the mucous membrane of the conjunctiva to environmental allergens.
Immunologic diseases of the eye can be grossly divided into two major categories: antibody-mediated and cell-mediated diseases. As is the case in other organs, there is ample opportunity for the interaction of these two systems in the eye.
ANTIBODY-DEPENDENT & ANTIBODY-MEDIATED DISEASES
Before it can be concluded that a disease of the eye is antibody-dependent, the following criteria must be satisfied:
There must be evidence of specific antibody in the patient’s serum or plasma cells.
The antigen must be identified and, if feasible, characterized.
The same antigen must be shown to produce an immunologic response in the eye of an experimental animal, and the pathologic changes produced in the experimental animal must be similar to those observed in the human disease.
It must be possible to produce similar lesions in animals passively sensitized with serum from an affected animal upon challenge with the specific antigen.
Unless all of the above criteria are satisfied, the disease may be thought of as possibly antibody-dependent.
In such circumstances, the disease can be regarded as antibody-mediated if only one of the following criteria is met:
If antibody to an antigen is present in higher quantities in the ocular fluids than in the serum (after adjustments have been made for the total amounts of immunoglobulins in each fluid).
If abnormal accumulations of plasma cells are present in the ocular lesion.
If abnormal accumulations of immunoglobulins are present at the site of the disease.
If complement is fixed by immunoglobulins at the site of the disease.
If an accumulation of eosinophils is present at the site of the disease.
If the ocular disease is associated with an inflammatory disease elsewhere in the body for which antibody dependency has been proved or strongly suggested.
Allergic conjunctivitis (AC) is characterized by conjunctival edema, along with one or more of pruritus, conjunctival hyperemia, chemosis, tearing, and a burning sensation, following exposure to an offending allergen (SEE ALSO CHAPTER 5). In severe cases, due to a compromise in the tear film, photophobia and blurred vision can be present. AC is classified as seasonal allergic (hay fever) conjunctivitis (SAC) (usually following exposure to pollen) or perennial allergic conjunctivitis (PAC) (usually following exposure to dust mites, mold, animal dander and occupational allergens).
AC is one of the few inflammatory eye ...