METHODS: Sixty-eight patients diagnosed as initial ipsilateral NAION(68 eyes)in NAION group and another 68 patients(68 eyes)matched in age, gender and systemic diseases in Control group were selected from June 2014 to June 2016 were enrolled in this study and evaluated for their levels of homocysteine(Hcy), blood lipids, folic acid and vitamin B12, as well as carotid Doppler ultrasonography. The visual functions were also examined in patients with NAION.

RESULTS: The levels of Hcy(24.8±13.9μmol/L), total plasma cholesterol(4.5±1.0mmol/L), triglyceride(2.0±0.9 mmol/L)and low-density lipoprotein(2.9±0.8mmol/L)in NAION patients were significantly higher(P<0.05)than those in Control group(11.1±8.2μmol/L, 3.8±0.7mmol/L, 1.5±0.5mmol/L and 2.3±0.5mmol/L)while the level of vitamin B12 decreased significantly(315.6 ±214.5pg/mL, P<0.05)in NAION group in comparison with those(467.9±198.2pg/mL)in Control group. However, no significant differences in the artery resistance and inner diameter of the internal carotid were detected between the two groups. The mean deviation(MD)of the visual field was 16.6±7.5dB in NAION group. The levels of Hcy, vitamin B12, folic acid and blood lipid and the presence of systemic diseases were not the risk factors for the visual field damage in NAION patients. MD value was associated with the amplitude and peak latency of P100 waves.

CONCLUSION: Hyperhomocysteinemia, hyperlipidemia and low vitamin B12 are the risk factors of in NAION patients. These risk factors, however, are not related to the extent of visual field damage. To some extent, the amplitude and peak latency of visual evoked potentials can reflect the extent of visual field damage.