Purpose: To investigate the relationship between idiopathic nonarteritic ischemic optic neuropathy (NAION) and serum lipid levels in patients </= 50 years of age.
Design: Case-control study.
Participants: Thirty-seven consecutive patients with NAION and 74 age- and gender-matched comparison patients.
Methods and main outcome measures: Serum lipid levels and the presence of several historical diseases and exposures were abstracted from the medical records in cases and controls.
Results: The mean total cholesterol level was significantly increased in patients with NAION compared with controls (235.4 vs. 204.0 mg/dl, P < 0.001). The odds ratio of having high blood cholesterol (>/= 240 mg/dl) with NAION was 3.3 (95% confidence interval, 1.4-7.8), and the likelihood increased when the comparison was restricted to nondiabetic patients. Diabetes mellitus was more common in cases than controls (P = 0.027), but systemic hypertension was not significantly different (P = 0.63). No patient (0 of 24) had a magnetic resonance imaging study consistent with optic neuritis or central nervous system demyelination. Visual improvement was uncommon.
Conclusions: This study demonstrates that hypercholesterolemia is associated with NAION in younger patients. NAION may be the first manifestation of a lipid disorder, a previously unrecognized syndrome. These patients have experienced a focal, microvascular central nervous system ischemic event at a relatively young age. Aggressive treatment of lipid abnormalities in these patients may be warranted.