The Dangers of Fun in the Sun (or in the metal shop): A Case of Photokeratitis
“Photokeratitis is an inflammatory ocular condition that typically manifests six to twelve hours after lengthy or copious corneal exposure to UV light…”
CASE
A 25-year-old male without significant past medical history presented to the emergency department with severe bilateral eye pain, as well as associated “gritty” feeling in his eyes. At the onset of symptoms, he also had photophobia and tearing, which improved after taking ibuprofen and acetaminophen at home. The patient worked as a welder. He stated that the morning prior to arrival he performed six hours of "fire watch,” which involves watching welders at work to keep a lookout for any unintended or uncontrolled fires. He was not wearing eye protection. He denied any direct trauma to the eye. He denied blurry or double vision, or discharge from the eyes.
Vital signs were within normal limits. On exam, the patient did not have a visual field deficit. Vision was 20/20 OD, OS, and OU. Extraocular movements were intact without nystagmus or proptosis. Pupils were 3 mm and reactive bilaterally. There was no discharge or hordeolum on exam. There was mild bilateral conjunctival injection and chemosis without hemorrhage. The patient’s pain improved after administration of tetracaine eye drops. With eversion of the lids and corneal examination, no foreign body was identified. Fluorescein stain revealed diffuse punctate uptake on the cornea bilaterally. The remainder of the physical examination was unremarkable.
DIAGNOSIS
Photokeratitis, also known as ultraviolet (UV) keratitis
DISCUSSION
Photokeratitis is an inflammatory ocular condition that typically manifests six to twelve hours after lengthy or copious corneal exposure to UV light. Common sources include welding, damaged metal halide lights, tanning beds, laboratory UV lights, eclipses, and exposure to sunlight near snow, water, and/or altitude. This exposure causes corneal epithelial cell damage and death, which subsequently leads to desquamation and exposes corneal nerves, causing severe pain.
Diagnosis is based on history and physical examination, including fluorescein stain, and can be aided by slit lamp examination. Other common associated symptoms and examination findings include photophobia, tearing, foreign body sensation, blepharospasm, chemosis, and conjunctival injection. Some patients may have temporarily decreased visual acuity. Fluorescein stain reveals diffuse punctate uptake on the cornea (see Fig 1).
Figure 1: Characteristic florescein stain findings in photokeratitis
Taken from: “Ultraviolet Keratitis: Diagnosis and treatment” [1]
Analgesia is the mainstay of treatment, including acetaminophen, nonsteroidal anti-inflammatory drugs, and opioids. Topicals, such as lubricating saline eyedrops and erythromycin ointment, can also provide some relief. Antibiotic eyedrops are not indicated. Cycloplegics can be considered but are generally not utilized because they dilate the eye and lead to temporarily decreased vision. There is no evidence that eye patching hastens or improves healing, although it may provide comfort to some patients.
The cornea generally re-epithelializes in 24-72 hours, which leads to resolution of the patient’s pain. Most patients have no permanent effects on their visual acuity. If a patient’s pain does not improve within 24-48 hours, he or she should seek evaluation by an ophthalmologist. All patients presenting with UV keratitis should be educated on the importance of eye protection, which can prevent this condition altogether.
CASE RESOLUTION
The patient’s pain was well controlled with ibuprofen and acetaminophen he had taken prior to arrival. He was discharged on this pain control regimen. He was instructed to purchase over the counter artificial tear drops to aid with symptomatic relief. He was given erythromycin topical ointment to apply three times a day for five days. He was instructed to follow up with his ophthalmologist within the next two days if his symptoms did not improve. He received education about UV keratitis and the importance of eye protection in the future.
TAKE AWAYS
Photokeratitis is a painful ocular condition resulting from excessive UV light exposure, such as from welding or exposure to sunlight near snow, water, and/or altitude.
Fluorescein stain shows diffuse punctate uptake on the cornea.
Treatment includes analgesia with oral medications, lubricating eye drops, and erythromycin ointment.
Most patients have resolution of symptoms within 1-3 days and do not have any permanent ocular damage.
Author: Alexandra Pusateri, MD, is a current third-year resident at Brown Emergency Medicine Residency
Faculty Reviewer: Michelle Myles, MD, is an assistant professor and clinician educator at Brown Emergency Medicine.
REFERENCES
Bacig C, Hawthorne C. Ultraviolet Keratitis: Diagnosis and treatment. Visual Journal of Emergency Medicine. 2023;32:101788-101788. doi:https://doi.org/10.1016/j.visj. 2023. 101788
Cullen A. Photokeratitis and Other Phototoxic Effects on the Cornea and Conjunctiva. International Journal of Toxicology. 2002;21(6):455-464. doi:https://doi.org/10.1080/10915
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Bergmanson J. Corneal Damage in Photokeratitis--Why Is It So Painful? Optometry and Vision Science. 1990;67(6):407-413. doi:https://doi.org/10.1097/00006324-199006000-00004
Kirschke DL, Jones TF, Smith NM, Schaffner W. Photokeratitis and UV-Radiation Burns Associated With Damaged Metal Halide Lamps. Archives of Pediatrics & Adolescent Medicine. 2004;158(4):372-376. doi:https://doi.org/10.1001/archpedi.158.4.372
Willmann G. Ultraviolet Keratitis: From the Pathophysiological Basis to Prevention and Clinical Management. High altitude medicine & biology. 2015;16(4):277-282. doi:https://doi.org/10.1089/ham.2015.0109