Evaluation of iris epithelial and stromal thickness in patients with migraine by using optical coherence tomography

Abstract

Objective: The amount of light reaching to the retina is an important factor for photophobia formation. Therefore, investigation of iris thickness in patients with migraine can be valuable for revealing their susceptibility to photophobia. In this study, it was aimed to evaluate the iris epithelial and stromal thickness, retinal ganglion cell layer (RGCL) thickness, and retinal nerve fibre layer (RNFL) thickness of patients with migraine. Methods: Forty-nine migraine patients (Group 1) and 50 control participants (Group 2) were included into this study. For obtaining standard measure in all participants, the epithelial and stromal thickness of dilatory and sphincter iris muscle was measured from the equal distance to the pupillary margin by using anterior segment mode of optical coherence tomography (AS-OCT). Additionally, RNFL and RGCL thicknesses were measured by using posterior segment mode of OCT (PS-OCT). Results: The epithelial thickness of iris sphincter muscle and the epithelial thickness of iris dilatory muscle was found to be significantly higher in patients with migraine compared to control subjects (p<0.001, p=0.001 respectively). Additionally the stromal thickness of both iris sphincter and iris dilatory muscle (p<0.001, p<0.001 respectively) as well as the total thickness of iris sphincter and iris dilatory muscle was significantly higher in patients with migraine than control subjects (p<0.001, p=0.02 respectively). However, no significant difference was found between patients with migraine and control subjects in terms of RNFL and RGCL thicknesses (p=0.1 and p=0.7 respectively). Conclusion: The finding of high epithelial and stromal iris thickness in patients with migraine may support the possible role of increased pupillary dynamic in photophobia formation.