The relation between retrobulbar blood flow and posterior ocular changes measured using spectral-domain optical coherence tomography in patients with obstructive sleep apnea syndrome

Abstract

PurposeTo investigate the effect of posterior ocular hemodynamics on the retinal nerve fiber layer (RNFL), choroid thickness (CT) and central macular thickness (CMT) in patients with obstructive sleep apnea syndrome (OSAS) and to reveal the association with glaucomatous optic neuropathy.MethodsThe research was planned as a prospective, randomized study. the ophthalmic, retinal and posterior ciliary artery pulsatile index (PI) and resistive index (RI) were measured by colored Doppler sonography. RNFL thickness, CMT and CT were then measured by spectral-domain optical coherence tomography.ResultsSixty subjects were divided into four groupsmild, moderate and severe OSAS and a control group. There were 16 subjects in the control group, 14 in the mild OSAS group, 15 in the moderate OSAS group and 15 in the severe OSAS group. Ophthalmic artery and central retinal artery PI and RI values of the OSAS patients did not show statistically significant difference than those of the control group, but posterior ciliary artery (PCA) PI and RI values were significantly higher. in addition, mean, superior and inferior RNFL thickness values were significantly lower than those in the control group. Moreover, the glaucoma prevalence of the OSAS patients in this study was 6.8% and all of these patients were in the severe OSAS group.ConclusionPI and RI values of the PCA, which supplies the optic nerve, show a linear increase as the apnea hypoxia index values in OSAS. As the grade of OSAS improves, this situation leads to a more serious ischemic optic neuropathy. Furthermore, the prevalence of glaucoma in this study is found to be higher in the severe OSAS group.