Optical Coherence Tomography Findings in Primary Headache Disorders: Is pain duration a clinical correlate?

Objective: Ganglion cell layer thickness (GCLT) may be used as a potential marker for central neural changes. We compared GCLT by using spectral domain optical coherence tomography (SD-OCT) in patients with primary headache disorders and healthy controls. We seeked whether there was any difference between the headache groups and whether any clinical parameters correlated to GCLT. Methods: Fifty three primary headache patients, 11 age and sex-matched healthy subjects were included in this cross-sectional study after power analysis. All subjects underwent SD-OCT. The duration of disorder, headache frequency, severity, duration of pain, presence of ocular pain, and accompanying symptoms have been collected. Results: Mean GCLT of the headache group was 15.7 ± 3.8 µm (mean ± standard deviation) and the control group was 17.5 ± 2.4. The difference was not statistically significant. When we compared the controls, migraine and tension-type headache patients' GCLT values, we found a significant difference (ANOVA, p= 0.001). Migraine patients had thinner GCLT compared to all non-migraine headache patients (p = 0.01). Intraocular pressure values of migraine patients and non-migraine patients were not statistically significantly different (p = 0.13). The only clinical parameter that correlated with GCLT was pain duration (r = -0.43 and p = 0.01). The patients with white matter lesions had thinner GCLT (p = 0.046). Conclusion: Our results suggest that not long-term sufferring from pain but migraine pathophysiology itself seems to affect neuroretinal tissue. Pain duration was moderately and inversely correlated to GCLT, meaning that the longer the headache, the thinner the ganglion cell layer is.