PURPOSE: To describe signs and symptoms of latex allergy associated with the use of the TonoPen (Mentor, Norwell, Massachusetts) in a patient with severe latex allergy. METHODS: Case report. In a 13-year-old girl with a history of severe latex allergy, intraocular pressure was obtained with a TonoPen. RESULTS: TonoPen covers that contained latex induced agitation, bilateral conjunctival injection, eyelid erythema, and eyelid edema in this latex-allergic patient. Use of a fingertip from a sterile nonlatex glove provided accurate intraocular pressure measurements with the tone-pen. without a local or systemic reaction. CONCLUSION: In patients with latex allergies, TonoPen covers that contain latex may induce a substantial local and systemic reaction. (C) 1999 by Elsevier Science Inc. All rights reserved.