The Eyes Have It: A Low-Cost Model for Corneal Foreign Body Removal Training

This corneal foreign body simulator is designed to instruct junior emergency medicine (EM) residents and medical students with an interest in emergency medicine.

Eye complaints are common in the emergency department (ED), accounting for approximately 2 million ED visits each year.1 Corneal foreign bodies (CFB) account for approximately 7.5% of these presentations, and many EM providers are uncomfortable with removal procedures.1-3 Simulation has been demonstrated to improve provider comfort with this skill.4,5 Previous models for CFB removal have been created using wax over glass spheres, molded materials with silicone and ballistics gel, bovine eyes, cardboard glove boxes with ink stains simulating foreign bodies and rust rings, and agar plates with pepper-corns. 4-9 Often, these models are expensive or time-consuming to create or lack spatial realism.We propose that a simple, inexpensive model will be effective in increasing emergency provider comfort with CFB removal under slit lamp magnification in addition to increasing provider comfort using a slit lamp.

By the end of the session, the learner should be able to adequately focus a slit lamp in order to identify and magnify a corneal foreign body and demonstrate safe technique for removal of a corneal foreign body under slit lamp guidance.

We created a low-fidelity CFB simulator for approximately $15 utilizing a Styrofoam ball, toothpicks, grapes, novelty glasses, and magnesium shavings. Toothpicks secured grapes into simulated orbits, scooped out of a Styrofoam ball. We fastened the Styrofoam ball to the slit lamp using medical tape. We added novelty glasses to simulate working around facial features. A senior resident instructor then used forceps to insert small magnesium shavings into the grapes to simulate foreign bodies. Participants received an introduction on techniques for successful CFB removal using the bevel of a needle under slit lamp guidance.10,11 They practiced using the models under supervision of an instructor.

We conducted a prospective trial using a convenience sample of 19 learners at a university-based EM residency program, including EM interns, one emergency advanced-practice clinician, and fourth-year medical students participating in an EM sub-internship. We analyzed results using a Fisher's exact test.

Before training, few participants (36.8%) had observed a corneal foreign body removal, and only 15.8% had performed the procedure. More than half (52.6%) of participants said they were somewhat or very comfortable using a slit lamp before the training and 89.5% were somewhat or very comfortable after training (p=0.029). None of the participants were somewhat or very comfortable removing CFBs before the training and 84.2% were somewhat or very comfortable post-training (p<0.001).

Results suggest that simulation with this low-cost model effectively improves provider comfort in CFB removal in addition to improving comfort using a slit lamp.

Eye exam, eye injury, ocular injury, corneal injury, corneal foreign body, slit lamp, corneal foreign body removal.