Purpose: To study the cause of ocular hypertension in patients with Graves ophthalmopathy.
Methods: Intraocular pressure was measured in 190 eyes of 95 patients (mean age, 42 years; range, 11 to 86 years) with Graves ophthalmopathy. In six eyes (four patients), changes in intraocular pressure were also analyzed upon orbital decompression.
Results: The mean intraocular pressure +/- SD in 190 eyes was 18.36 +/- 4.02 mm Hg (range, 10 to 34 mm Hg). The intraocular pressure in 42 of the 190 eyes was 21 mm Hg or more. The intraocular pressure in 76 eyes with proptosis of 19 mm or more was 19.96 +/- 4.49 mm Hg (range, 14 to 34 mm Hg), whereas the intraocular pressure in 114 eyes with proptosis of less than 19 mm was 17.08 +/- 3.38 mm Hg (range, 10 to 28 mm Hg). The difference in the values between these two groups is statistically significant (two-tailed t test, P < .001). The mean intraocular pressure in six eyes decreased from 23.23 to 18.82 mm Hg upon orbital decompression, a difference that was statistically significant (two-tailed paired t test, P < .001). The coefficient of outflow facility was normal in these six eyes.
Conclusion: These findings suggest that ocular hypertension in patients with Graves ophthalmopathy is caused, in part, by increased intraorbital pressure associated with proptosis.