Botox has been approved to smooth wrinkles, help with headaches and counteract strabismus—to name a few—but a new study suggests thee injections may also improve photophobia and dry eye symptoms in patients being treated for migraine.

Investigators conducted a retrospective review of 76 patients who received Botox injections for chronic migraine from August through December 2017 at the Miami Veterans Affairs Medical Center Neurotoxin Clinic. Patients were given standardized, validated surveys to assess symptoms prior to and after Botox injections, in addition to a phenol red thread (PRT) test to measure preinjection tear volume.

Researchers found preinjection migraine, photophobia and dry eye symptom scores were all significantly correlated and none were associated with preinjection PRT results. After Botox, improvements in migraine, photophobia and dry eye symptoms were also significantly correlated and, similarly, did not associate with preinjection PRT results. Additionally, the study reported photophobia scores significantly improved following Botox, and dry eye symptoms also significantly improved in patients with severe symptoms at baseline (DEQ-5 score ≥12). In logistic regression analysis of all individuals with dry eye symptoms (DEQ-5 ≥6), the more severe dry eye sufferers saw the most improvement.

Botox “significantly improved photophobia in patients being treated for migraine and also improved dry eye symptoms in patients with severe symptoms at baseline, independent of baseline tear film volume. These improvements may be due to modulation of shared trigeminal neural pathways,” researchers noted.