Effect of eye rubbing on signs and symptoms of allergic conjunctivitis in cat-sensitive individuals

Objective: To evaluate the effect of eye rubbing on signs and symptoms of a llergic conjunctivitis in cat-sensitive individuals. Design: Two prospective, nonrandomized comparative studies. Participants: Thirteen patients in the first study and 20 patients in the s econd study with a documented history of acute allergic conjunctivitis indu ced by exposure to cats were enrolled. Intervention: In the first trial, all patients had one eye rubbed 15 times by the investigator without exposure to airborne allergens. Both eyes were evaluated after 5, 15, 30, and 60 minutes using subject questionnaires and slit-tamp examination. At least 1 week later, each patient was exposed to c at dander for 75 minutes; 15 minutes after entering the cat room, each pati ent had one eye rubbed 15 times by the examiner. Subjects' eyes were then e valuated using questionnaires and slit-lamp examination. in the second tria l, the visits were identical to the first trial, except that the rubbed eye in each visit was rubbed 20 times and with more force, and that patients w ore masks during exposure to cat dander. Main Outcome Measures: In both studies, the difference between patients' ru bbed and nonrubbed eyes with respect to ocular itching, chemosis, and hyper emia was noted 5, 15, 30, and 60 minutes after controlled eye rubbing. Results: Without exposure to the cat room, rubbed eyes exhibited increased itching at 5 minutes in both studies and at 15 minutes in the second study (P < 0.05), increased chemosis at 5 and 15 minutes in the second study (P < 0.05), and increased hyperemia at 5 minutes in the second study (P < 0.05) compared with nonrubbed eyes. During exposure to cat dander, rubbed eyes c onsistently exhibited increased itching at 5, 15, and 30 minutes in the fir st and second study as well as at 60 minutes in the second study compared w ith nonrubbed eyes. Furthermore, during exposure to cat dander, rubbed eyes consistently exhibited increased chemosis at 5 and 15 minutes (P < 0.05) a nd increased hyperemia at 5, 15, and 30 minutes (P < 0.05) in the second st udy compared with nonrubbed eyes. Conclusions: Firm eye rubbing causes a mild and transient increase in ocula r itching, chemosis, and hyperemia. However, after exposure to cat allergen s in cat-sensitive individuals, the effects of eye rubbing are longer and m ore dramatic. Eye rubbing may play a role in ocular signs and symptoms of a llergic conjunctivitis in cat-sensitive individuals, especially after expos ure to cat dander. (C) 2000 by the American Academy of Ophthalmology.