Normal respiratory chain function in patients with low-tension glaucoma

Objective: To test the hypothesis that low-tension glaucoma has a pathogenesis similar to Leber's hereditary optic neuropathy and results from a defect in the mitochondrial respiratory chain. Methods: Mitochondrial fractions were prepared from skeletal muscle samples collected from eight subjects with low-tension glaucoma. Their oxidative metabolism was compared with that of age- and sex-matched controls. Skeletal muscle DNA prepared from the subjects with glaucoma was also screened for the 3460, 11 778, and 14 484 mitochondrial DNA mutations that are associated with Leber's hereditary optic neuropathy. Results: No subject with low-tension glaucoma had a defect in respiratory chain activity or one of three mitochondrial DNA mutations that are commonly associated with Leber's hereditary optic neuropathy. Conclusion: Although these results do not exclude the possibility that low-tension glaucoma is caused by an organ-specific defect of mitochondrial function, we have excluded a systemic defect of the mitochondrial respiratory chain.