The ocular reactions to caterpillar hairs are diverse in nature and location, ranging from a toxic reaction to the external foreign bodies, keratoconjunctivitis or the formation of conjunctival nodules, to intense iritis, vitritis or papillitis. Four cases are presented in this paper to illustrate the various degrees of ocular involvement. Included are clinical photographs of intravitreal and subretinal hairs. A classification of these reactions is suggested to facilitate the choice of treatment.