May 2016 Online Photo Diagnosis

By William Townsend, OD, FAAO

UV Keratitis Secondary to Welding Burns

This 72-year-old male presented with unilateral ocular pain and blurred vision. The previous evening, he was welding and failed to use eye protection because he could not find his welding goggles. Realizing the potential for “welding burns,” he turned his head away from the “flash,” closed his left eye, and used only his right eye to weld. Later that night, he began to experience pain, photophobia, and blurring in his right eye.

His presenting visual acuities were OD 20/25, OS 20/40. The right side of his face was erythematous, and his right eyelid was swollen. Biomicroscopy revealed diffuse corneal staining concentrated on the temporal aspect of his right eye; the left cornea showed very limited superficial punctate keratitis. He also had mild, bilateral nuclear sclerosis.

Our diagnosis was unilateral welding photokeratitis and UV-induced dermatitis. The goals when treating photokeratitis are to reduce inflammation, enhance patient comfort, and promote healing of the corneal epithelium. I instilled one drop of 5% homatropine solution followed by two drops of Prolensa (Bausch + Lomb). Once the patient reported improvement in comfort, I placed a Night & Day lens (Alcon) (8.4mm base curve) on his cornea. Within three days, he was much improved, and we removed the bandage lens.

It is not unusual for eyecare providers to encounter patients who have welding keratitis. A four-year study of Taiwanese industrial workers revealed that photokeratitis secondary to welding was by far the most common work-related eye injury.¹ Welding generates a broad spectrum of radiant energy, including visible and invisible radiant energy wavelengths, but UVB is thought to be the main actinic component.² The symptoms of welding photokeratitis typically begin six to 12 hours after the exposure to light radiation.

Understanding the precise nature of welding-generated energy is problematic because of the broad spectrum of welders ranging from conventional (arc) units to plasma welders. The latter have become popular and more common because they reduce the time needed for welding. Plasma welders may generate temperatures in excess of 30,000º Celsius, resulting in a significant amount of radiant energy.

Analysis of mouse corneas subjected to UV light suggests that the corneal epithelium protects underlying corneal structures by absorbing a substantial amount of radiant energy applied to the eye.³ Doughty and Oblak reported that even in individuals who suffered repeated cases of significant welding-related keratitis, the corneal endothelial cell count was unaffected.⁴

Eyecare providers typically recognize the effects of unprotected welding on the cornea, but may not appreciate the potential influence of welding on the retina, especially on the macula. Prolonged or repeated exposure to intense near UV emissions may damage the central photoreceptors, leading to maculopathy. The initial presentation of welding-induced phototoxic trauma includes reduced visual acuity and macular edema. Welding maculopathy may ultimately cause depigmentation of the retinal pigment epithelium, alteration of the other retinal layers, and a small central scotoma. Obtaining optical coherence tomography of the macula may be extremely valuable in patients who have unexplained vision reduction and a history of unprotected welding.

Dr. Townsend practices in Canyon, Texas, and is an adjunct professor at the University of Houston College of Optometry. He is president of the Ocular Surface Society of Optometry and conducts research in ocular surface disease, lens care solutions, and medications. He is also a consultant or advisor to Alcon, Allergan, NovaBay, TearScience, TearLab, and Science Based Health. Contact him at drbilltownsend@gmail.com.

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