Graves' ophthalmopathy. Correlation of saccadic eye movements with age, presence of optic neuropathy, and extraocular muscle volume
S. E. Feldon, L. Levin and S. K. Liu
Department of Ophthalmology, University of Southern California School of Medicine, Los Angeles.
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.
