Botox Effective for Dry Eye and Photophobia

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This month, News in Review highlights selected papers from the original papers sessions at AAO 2018. Each was chosen by the session chair because it presents important news or illustrates a trend in the field. Only 4 subspecialties are included here; papers sessions will also be held in 5 other fields. For more information, see the Meeting Program, which you’ll find in your meeting bag, or the Mobile Meeting Guide.

Doctors have been using botulinum toxin A (BoNT-A) to treat everything from facial wrinkles to stra­bismus. Now a study performed at the University of Miami supports adding photophobia and dry eye to the list, at least in patients with migraine.

“We found that dry eye symptoms, photophobia, and migraine pain sever­ity were correlated and all improved following BoNT-A injection,” said Ryan Diel, MD, now a resident in internal medicine and ophthalmology at the University of Iowa in Iowa City. “Dry eye and migraine were initially thought of as 2 different diseases and treated independently. But these findings sug­gest that the symptoms are linked and represent different manifestations of the same underlying disease.”

A cohort study. For this study, 76 patients at the Miami Veterans Affairs Hospital with chronic migraine, for which BoNT-A is approved, were asked to assess the severity of migraine, pho­tophobia, and dry eye symptoms prior to injection.

Then, 2 to 8 weeks postinjection, patients answered the same questions to assess treatment response. The researchers also evaluated whether preinjection tear volume, measured by the phenol red thread test (PRT), had any effect on symptoms.

Confirmatory findings. The study replicated findings of an earlier cross- sectional study at the same medical center.¹ Migraine, photophobia, and dry eye symptom scores were all significantly correlated, and symptoms improved following BoNT-A injections.

A surprise. However, PRT results did not correlate with symptom severity, meaning patients with photophobia and dry eye had relatively normal tear volume at baseline. “This suggests that the symptoms may not be related to abnormalities in the ocular surface,” Dr. Diel said. In other words, patients with migraine may experience significant photophobia and dry eye symptoms despite relatively normal ocular surface parameters.

Looking ahead. In this study, patients received approved BoNT-A injections for chronic migraine. “The question is whether BoNT-A can be used in patients with dry eye not asso­ciated with migraine,” Dr. Diel said. He plans to address that issue by using off-label BoNT-A injections in individ­uals who have dry eye and photophobia but are not affected by migraines.

“I hope that this and future studies will prompt physicians to consider new treatments for dry eye that is unre­sponsive to traditional therapies and in which neuropathic mechanisms are be­lieved to underlie symptoms,” he said.

—Miriam Karmel

1 Diel RJ et al. Ophthalmology. 2018;125(1):139-140.

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Relevant financial disclosures—Dr. Diel: None.

For full disclosures and the disclosure key, see below.

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