Ultrasound Biomicroscopy in the Diagnosis and Management of Pars Planitis Caused by Caterpillar Hairs Muna Bhende, MD, Jyotirmoy Biswas, MD, Tarun Sharma, MD, Sumeet K. Chopra, MD, Lingam Gopal, MD, and Cyrus M. Shroff, MD PURPOSE: To report the use of ultrasound biomicroscopy in the detection of caterpillar hairs in the pars plana in a patient with unilateral pars planitis. METHOD: Ultrasound biomicroscopic imaging of the an- terior segment of the eye. RESULTS: Ultrasound biomicroscopy located a hair in the posterior chamber at the first visit and five more in the pars plana 1 month later. This finding was confirmed intraoperatively. CONCLUSION: Ultrasound biomicroscopy is useful in the diagnosis and management of unilateral pars planitis of uncertain cause. (Am J Ophthalmol 2000;130: 125–126. © 2000 by Elsevier Science Inc. All rights reserved.) T HE VARYING CLINICAL MANIFESTATIONS OF OPHTHAL- mia nodosa may result in loss of the eye because of persistent severe uveitis. 1,2 The diagnosis is aided by imaging modalities such as specular microscopy 3 and ultra- sound imaging. 4 Ultrasound biomicroscopy is invaluable in the assessment of the anterior segment up to the pars plana and has been found useful in detection of minute intraoc- ular foreign bodies in these areas. 5 We report a case of unilateral pars planitis where ultrasound biomicroscopy provided a definitive diagnosis. A 53-year-old man presented with recurrent uveitis in the right eye of 8 months’ duration. He gave a history of rubbing his face with a towel contaminated with caterpillar hairs 1 year earlier. Approximately 60 hairs had been removed from the conjunctiva and cornea by his local ophthalmologist in 10 sittings. He was asymptomatic for 4 months, after which he developed uveitis unresponsive to topical, periocular, and systemic corticosteroids. On presentation, visual acuity in the right eye was 20/40; N18. There was evidence of anterior chamber flare and cells, vitreous haze, exudates over the pars plana, and cystoid macular edema. A suspicion of caterpillar hair– induced uveitis was entertained and ultrasound biomicros- copy was advised. It was performed with a 50-MHz probe (Zeiss Humphrey Instruments, San Leandro, California) and showed a single, high-reflective structure suggestive of a caterpillar hair between the iris and zonules from the 5:30 to 6:00 o’clock position (Figure 1). There was also localized iris and ciliary body thickening in this region. The patient was advised to undergo surgical removal but returned only a month later with a worsening of symptoms. Visual acuity was 20/120; N36, with an increase in exudation over the pars plana from the 6:00 to 8:00 o’clock position and localized peripheral tractional retinal detach- ment. Repeat ultrasound biomicroscopy showed the single linear structure as before and four similar structures in the ciliary body and pars plana from the 8:00 to 9:30 o’clock position, with one in the adjacent vitreous (Figure 2). There were highly reflective vitreous membranes causing detachment of the peripheral choroid. The patient underwent pars plana lensectomy and vitrectomy with an encircling band. Intraoperatively, ad- ditional hairs were seen in the episclera of the involved quadrant and one in the opposite quadrant. A total of seven hairs were removed from vascularized fibrous tissue in the pars plana from the 6:00 to 9:00 o’clock position. The hairs were teased out of the tissue with a sharp microvitreoretinal blade and removed by internal limiting membrane– holding forceps. The involved pars plana was treated by confluent cryopexy. Corticosteroids were con- tinued postoperatively. The eye was free of inflammation at 4 weeks’ follow-up. This report describes the importance of ultrasound biomicroscopy in the diagnosis and management of uni- lateral pars planitis caused by suspected intraocular cater- pillar hairs. Though removal of hairs from the vitreous cavity has been described, 2 their localization and removal from the pars plana is difficult. With the use of ultrasound biomicroscopy as a guide, surgical removal could be planned. The migratory capability of caterpillar hairs was demonstrated by the increase in number on repeat ultra- Accepted for publication Feb 25, 2000. From the Medical and Vision Research Foundations, Sankara Nethra- laya, Chennai, India. This study was supported by Vision Research Foundation, Chennai, India. Inquiries to Muna Bhende, MD, Sankara Nethralaya, Vision Research Foundation, 18 College Rd, Chennai 600 006, India; fax: 91-044- 8254180; e-mail: MDSAAA35@giasmd01.vsnl.net.in FIGURE 1. Ultrasound biomicroscopic image showing a highly reflective structure (white arrow) between the iris and zonules. BRIEF REPORTS VOL. 130,NO. 1 125