Graves' ophthalmopathy. Correlation of saccadic eye movements with age, presence of optic neuropathy, and extraocular muscle volume.

Quantitative infrared oculography was used to record saccadic eye movements of 49 patients with Graves' ophthalmopathy. Peak saccadic velocities were decreased in those patients who developed or presented with optic neuropathy. This effect was more pronounced for larger eye movements. Peak saccadic velocity also decreased as total extraocular muscle volume and limitation of ocular motility increased. For any given extraocular muscle volume, peak saccadic velocity was 40 degrees/s slower in patients 40 years or older than in younger patients. The relationship between velocity and motility limitation was most pronounced for intermediate muscle volumes (8% to 15% of total orbital volume). Saccadic velocities in those patients with optic nerve compression often improved following treatment. This study demonstrated that eye movement recording was a useful adjunct in evaluation of patients with Graves' ophthalmopathy. Furthermore, age-related lowering of peak saccadic velocities implicated changes of extraocular muscle structure as a factor in the development of optic neuropathy.