THE DISTRIBUTION OF TISSUE ANTIGENS IN THE EYE

When the eye responds to an antigen the reaction is not always confined to one tissue. I t is common knowledge that cornea and conjunctiva may react simultaneously to the same antigen. I t is also known that allergies of the skin may involve the eye. The dermatitis is then accompanied by a reaction in the conjunctiva; or in conjunctiva and cornea; or in the lens. There is a tendency in ophthalmology to base such reactions on a similar embryologic origin o l the tissues concerned although there is no further evidence to support thc thesis. The explanations for the ocular complications of atopic dermatitis are illustrative examples in this respect. Atopic dermatitis is so frequently connected with asthma, hay fever, urticaria, blood eosinophilia and positive skin tests that an allergic etiology is highly suggestive and widely held. The incidence of cataracts in this entity has been repeatedly explained by the fact that skin and lens might respond to the same antigen-antibody reactions since they are both of ectodermal origin. Keratoconjunctivitis (Hogan, 1953) is another ocular complication of atopic dermatitis, and again a common ectodermal origin was referred to (Theodore and Schlossman, 1958). Retinal detachment (Mylius, 1949; Balyeat, 1957) has been reported in cases of atopic dermatitis; also a relatively high incidence of retinal detachments occur in these patients after cataract extraction (Coles and Laval, 1952). The detachments were supposedly the result of severe retinal edema which was explained by the fact that the retina, a neuroectodermal tissue, responded to an antigen just as the skin reacts with a wheal (Balyeat, 1957). Others (Coles and Laval, 1952) believed that the detachments were secondary to a diseased