Abstract
Abstract: :
Purpose: Although a vasculopathic process, the etiology of non–arteritic anterior ischemic optic neuropathy (NAION) is unknown. Altered cerebral blood flow has been demonstrated in patients with Raynaud’s phenomenon (RP). This study evaluates the historical incidence of RP in a population with NAION and compares macular blood flow in subjects with NAION without RP, NAION with RP, and controls. Methods: Retrospective chart review to identify patients with NAION. Subjects with NAION completed a questionnaire to identify RP symptoms. Subjects with NAION (without and with RP) who completed questionnaires were randomly selected for a study involving cold water provocation before and after macular blood flow measurement with blue field entoptoscopy (BFE). Five replicate measurements of leukocyte density and velocity were performed in both subjects with NAION (without and with RP) and controls. Subjects were examined for evidence of RP after cold water provocation. Leukocyte velocity and density between subject groups were compared by t–tests and nonparametric rank sum tests for measurements that did not meet normal distributional assumptions (two sided tests at alpha=0.05 were performed using SAS statistical software). Results: 24 subjects responded to the questionnaire. Prevalence of RP was 16.67% (4/24) in the NAION group versus 0% (0/10) in controls (p=0.17). 11 subjects with NAION (8 without and 3 with RP) and 10 controls participated in the clinical study. Velocity (mm/second) in the NAION without RP, NAION with RP, and control groups increased 15.3%, 26.0%, and 43.5%, respectively, from before to after cold water provocation, and was not statistically significant (p>0.10). Density (particles/mm2) measurements from before to after cold water provocation increased 28.1% and 12.8% in the NAION without RP and NAION with RP groups, respectively, and decreased 17.9% in the control group. These differences failed to reach statistical significance on absolute and relative scales (0.10>p>0.05). No subjects developed symptoms of RP during the study. Conclusions: No statistically significant difference in macular blood flow was found between the NAION and control groups. Population based studies have revealed the prevalence of RP to range from 5.8 to 20.2% in females and 4.1 to 12.7% in males[i], which is comparable to the prevalence of RP in the NAION group is this study. Small sample size limits comparison of prevalence between NAION and control groups is this study. [i] Paget S, Gibofsky A, Beary J. Manual of Rheumatology & Outpatient Orthopedic Disorders. © 2000, Lippincott.
Keywords: neuro–ophthalmology: optic nerve • visual impairment: neuro–ophthalmological disease • clinical (human) or epidemiologic studies: prevalence/incidence