INTRODUCTION: The aim of this study was to compare the levels of vitamin B12 (Vit B12), folic acid, serum ferritin, serum iron, and total iron binding capacity (TIBC) in patients with optic neuritis (ON) and non-arteritic ischemic optic neuropathy (NAION). It was hoped to determine whether these simple and inexpensive laboratory measurements are indicative for making a distinction between ON and NAION.
METHODS: In this retrospective study, the data of patients who were diagnosed with ON and NAION between September 2005 and December 2016 were reviewed. In all, 42 patients with NAION, 70 patients with ON, and 76 members of a control group, a total of 188, were enrolled in the study. All of the participants underwent a full ophthalmological examination and complete physical examination, including a detailed medical history and blood count and evaluation of the biochemical parameters, serum ferritin, Vit B12, folic acid, serum iron, and TIBC.
RESULTS: The mean serum ferritin level was 236±458.4 ng/mL for the NAION patients, 32.8±34.6 ng/mL for the ON patients, and 76.1±84.6 ng/mL for the control group. The mean serum Vit B12 level was 478±306.3 pg/mL for the NAION patients, 291.7±136.9 pg/mL for the ON patients, and 417.1±163.4 pg/mL for the control group. The mean serum folic acid level was 11.4±6.3 ng/mL for the NAION patients, 6.6±2.7 ng/mL for the ON patients, and 14.5±5.2 ng/mL for the control group.
DISCUSSION AND CONCLUSION: A higher serum ferritin level was significantly associated with NAION, and lower Vit B12 and folic acid was associated with ON patients. Serum ferritin, Vit B12, and folic acid measurements could be a useful method for distinguishing between NAION and ON before using complicated and invasive methods.