Regional hemodynamics of the eye in optic neuritis

Abstract

Background: Optic nerve disease accounts for up to 28% of all cases of visual disability. Although recent studies have demonstrated abnormal hemodynamics in optic neuritis (ON), results of different studies as well as data on the pathophysiology of vascular abnormalities are contradictory. Purpose: To assess regional hemodynamics on the basis of ophthalmic rheography (ORG) and rheoencephalography (REG) in patients with optic neuritis and those with complications of the disease. Material and Methods: Fifty-seven patients (82 affected eyes; 27 women and 30 men) who were examined for idiopathic ON at the Department of Ocular Inflammatory Disease, Filatov Institute of Eye Disease and Tissue Therapy, were included in the study and divided into four groups. They underwent a clinical ophthalmological examination as well as ORG and REG studies with the computerized rheography apparatus Reocom (Kharkiv). Results: Best-corrected visual acuity (BCVA) values were twofold to threefold lower for the eyes with partial optic atrophy (POA) after ON or those with macular involvement in ON than for the eyes with acute ON or prolonged ON. BCVA showed mild direct correlation with ocular pulse blood filling (OPBF) expressed as RQ (r = 0.24; р < 0.05), and negative correlation with the presence of complications following ON (r = -0.35; р < 0.05). RQ values in patients with acute ON were 15.5% higher than in controls (р < 0.05) and 35% and 31% higher than in patients with POA following ON and patients developing macular lesion following ON, respectively (р < 0.05). RQ values in patients with partial optic atrophy (POA) were 23.6% lower than in controls (р < 0.05), which reflected regional ischemic process. The odds ratio (OR) for the presence of a reduced RQ value (a) in the eye with POA following ON compared to the eye with acute ON was 9.2 (P < 0.05, 95% confidence interval 2.0–42.4), and (b) in the eye developing macular lesion following ON compared to the eye with acute ON was 4.3 (P < 0.05, 95% CI, 1.2–14.7). Pulse blood filling as assessed by rheography index (RI) in the internal carotid artery (ICS) was actually normal in patients with acute ON and 44% increased in patients with prolonged ON or outcome of ON compared to controls (р < 0.05). In addition, tonicity of large vessels in the ICS and VBS as assessed by alpha/Т (%) was normal in patients with acute ON and at average 15% higher in patients with complications following ON. Moreover, tonicity of small-caliber vessels as assessed by the dicrotic index (DCI) and diastolic index (DSI) values was at average 32.2% and 55%, respectively, higher in patients than in controls. Conclusion: We revealed features of ocular and brain hemodynamics in patients with acute ON, prolonged ON and those with complications of the disease.