It is wise not to handle hairy caterpillars as the hairs can stick in the skin and cause irritation or worse. Another hazard: Tiny hairs from caterpillars can break off of the caterpillar, become airborne and lodge in an unsuspecting person. A group of doctors* from Panjim, India write about a condition, Ophthalmia nods, that occurs when one of the tiny caterpillar hairs lands in the eye of a person. The hair can either float on the surface of the eye or be forced into the tissue due to movement of the eye relative to the eyelid. In some cases, hairs were present that caused no irritation. Other patients reported intense lacrimation, feeling the hair in their eye, edema of the eyelid and redness. The hairs in some cases abraided or punctured the cornea. Altogether, 192 hairs were reported from 17 patients. About half the patients acquired the hairs while riding in open air vehicles. The doctors advised wearing goggles or other eye protection during caterpillar season in India.
*Pratik Y. Doshi, Ugam Usgaonkar & Pradnya Kamat. (2016): A Hairy Affair: Ophthalmia nodosa Due to Caterpillar Hairs, Ocular Immunology and Inflammation. Published online: 20 Jul 2016.