Retinal Nerve Fiber Layer Thickness Changes in Migraine: A Meta-Analysis of Case-Control Studies

Background: The neurovascular dysfunction appears to be related to the development of migraines and it could be possible that hypoperfusion might also involve other areas besides brain, including the retina. Numerous studies have analyzed the ability of optical coherence tomography (OCT) to detect retinal nerve fiber layer (RNFL) thickness abnormalities and changes in migraine, but the results have not always been consistent. Therefore, we carried out a meta-analysis to evaluate the RNFL thickness measured with OCT in migraine.Methods: Case-control studies were selected through an electronic search of the Cochrane Controlled Trials Register, PUBMED and EMBASE. For the continuous outcomes, we calculated the weighted mean difference (WMD) and 95% confidence interval (CI). The statistical analysis was performed by RevMan 5.0 software.Results: Six case-control studies were included in the present meta-analysis, containing a total of 432 eyes in migraine patients and 288 eyes in healthy controls. The results of our study showed that there was a significant reduction in average RNFL thickness in patients with migraine compared to healthy controls (WMD=-3.67, 95% CI: -6.84 to -0.49, p=0.02). Additionally, differences of RNFL thickness in superior quadrant (WMD=-9.23, 95% CI: -15.63 to -2.82, p=0.005), inferior quadrant (WMD=-3.47, 95% CI: -6.73 to -0.22, p=0.04), nasal quadrant (WMD=-3.86, 95% CI: -7.10 to -0.61, p=0.02) and temporal quadrant (WMD=-3.10, 95% CI: -5.05 to -1.15, p=0.002) were all significant between the two groups.Conclusions: Our meta-analysis found that RNFL thickness in the migraine patients was thinner than that in the healthy control group. Given the limited sample size, further investigations are needed to validate these findings.