Approach to Corneal Disorders in the ED

In Medical Concepts by Hubert Yu1 Comment


Tom is a 38-year-old male who presents to the ED with a red left eye. It started yesterday at work and has been getting more painful. He describes feeling like something is stuck in his eye, despite washing it multiple times. His vision is “a bit blurry” in the left eye. He wears contact lenses occasionally, but mostly wears glasses. He denies headache.

Past medical history is significant for seasonal allergies, asthma, and genital herpes. He works as a car mechanic.

What is your differential diagnosis for corneal disorders in the ED? What physical exam and slit lamp findings would you look for?

Return to the Case

After a quick scroll through CanadiEM, you return to your patient Tom. You attempt to examine him but he screams “don’t touch my eye doc!”. You apply topical tetracaine, which improves his pain drastically. After 2 minutes, he allows you to examine him.

On inspection, you see a red left eye with watery discharge. His visual acuity is 20/20 bilaterally. His extra-ocular movements are normal and pupils are reactive. You move onto a slit lamp exam, carefully talking through the steps with the patient. Using plain diffuse light, you look under the eyelids, and then at the cornea. There is mild conjunctival injection but you do not see any hyphema, pus, or foreign body. 

You then instill fluorescein drops into the eye, and switch the slit lamp to the cobalt blue filter. This is what you see.10

Based on the slit lamp findings, you diagnose Tom with herpes simplex keratitis. You give him a prescription for Valacyclovir 1 g TID, arrange next day ophthalmology follow-up, and give him return instructions to come back if his pain worsens or vision deteriorates. 

This post was copyedited and uploaded by Kimberly Vella.


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  6. Njoya JM, Handor H, Lezrek O, Hafidi Z, Sabrane I, Daoudi R. Herpetic epithelial keratitis. QJM. December 2014:595-595. doi:10.1093/qjmed/hcu250
  7. Roat M. Herpes Zoster Ophthalmicus – Eye Disorders. Merck Manuals. Published 2018. Accessed 2019.
  8. Shaikh S, Ta C. Evaluation and management of herpes zoster ophthalmicus. Am Fam Physician. 2002;66(9):1723-1730.
  9. Trobe J. The Physician’s Guide to Eye Care. San Francisco, CA: American Acad. of Ophthalmology; 2012.
  10. Sterling J. Herpes simplex virus . Jeffrey Sterling, MD. Published 2018. Accessed 2019.

Reviewing with the Staff

As with all things in emergency medicine, a thorough history and physical is worth its weight in gold. Patients with painful eyes are often anxious. Early topical anesthetic can help ease the discomfort of the rest of the examination. As well, talking the patient through each portion of the examination often reassures the patient and helps them follow instructions easier. This will further facilitate a better quality examination. Finally, make sure to wear gloves and wash your hands thoroughly, as these pathogens can be extremely contagious!

Dr. James Shin CCFP(EM)

Hubert Yu

Hubert Yu is a Family Medicine resident at the University of Toronto. He is passionate about the use of technology in medical education, as well as quality improvement in emergency departments. In his spare time, he enjoys playing soccer and trying new foods.

Suhail Agarwal

Suhail is a first year Family Medicine resident at the University of Toronto. Outside of family medicine, he is interested in providing care to patients in acute settings such as the emergency department. In his free time he enjoys exercising, playing basketball/badminton, board games, video games and travelling.

Andrei Smarandache

Andrei Smarandache is a PGY1 in Family Medicine at the University of Toronto – Mississauga Trillium Site. In a previous life he worked in higher education policy. In addition to medicine, he is interested in health policy, politics, economics, and medical education. An avid indoorsman, Andrei likes to spend time with his kiddos, work on cars, and watch the occasional Netflix marathon.