Retinal vessel parameters in obstuctive sleep apnea

Abstract

PurposePilot study to explore retinal vessel parameters, calibres as well as vessel reactivity to flicker light provocation in a group of obstructive sleep apnea (OSA) patients.MethodsAll patients [n = 7] underwent a full eye examination including intraocular pressure measurement, visual field assessment (HFA 30‐2 incl. fovea threshold), ocular coherence tomography (Cirrus 3D, Zeiss: optic nerve head and macula centred), retinal photography, dynamic retinal vessel assessment using flicker light provocation (RVA, IMEDOS) and measurement of systemic blood pressure and oxygenation. Central retinal arterial and venous equivalents (CRAE and CRVE) were calculated using optic nerve head centred retinal photographs according to a standardised method, vessel reactivity to flicker light provocation was quantified by calculating the maximum, minimum and peak arterial and venous diameters following flicker light provocation. All data were compared to a group of age and gender matched patients suffering Diabetes Mellitus (DM).ResultsOSA patients (mean age: 65 +/− 7 years) showed significantly better retinal arterial (2.3%) and venous dilation (3.9%) to flicker light provocation compared to those suffering from DM (0.90% and 3.25% respectively). However, CRAE (156 +/− 19 au) but not CRVE (218 +/− 15 au) of OSA patients was significantly reduced compared to their diabetic counterparts (CRAE: 178 +/− 21 au; CRVE: 213 +/− 19 au).ConclusionsWhile OSA patients suffer from endothelial dysfunction, our small sample is a well controlled and motivated group of patients which might in part explain their better dilation capacity. Another explanation might be offered by through vessel calibers: diabetic patients showed markedly larger diameters which could reflect predicated vessels at rest and therefore contribute to a diminished dilatory capacity following flicker light provocation.