Case Report: Ophthalmia Nodosa Caused by Caterpillar Setae

Caterpillars can damage human health, including visual acuity, as a result of penetration of the setae into the eye or their layout on the eye tissue. However, the path of setae movement in the eye remains unclear. In this study, a 43-year-old woman was injured in the left eye by a caterpillar. Other than rubbing her eye, the patient did not attempt any type of treatment, and she visited our outpatient clinic 5 days after the accident. The patient's left eyelid was markedly swollen, with a visual acuity of 1.0 in the right eye and only 0.04 in the left eye. Images of the setae in the eye were taken using an oil lens microscope, which showed clearly their detailed characteristics. The setae were removed from the eye as much as possible. Topical eyedrops and oral steroids were used to reduce the inflammation. Vitritis and retinitis occurred at the 6-month follow-up and was classified as ophthalmia nodosa by the ophthalmologist. Before we did our study, some ophthalmologists believed that setae moved forward; however, we found that setae in the eye moved in a disorderly fashion. We also note that all setae should be removed. This case demonstrates that caterpillar setae in the eye move in a disorderly fashion and eventually caused ophthalmia nodosa.