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Show LETTERS TO THE EDITOR 305 formed at that time showed no abnormality. Visual evoked responses were normal both before and after exercise; bilateral simultaneous fluorescein retinal angiography was normal. The patient was started on verapamil in January 1984 with a marked reduction in his visual symptoms. When he was seen in February 1990, he reported having had only about two attacks in the past year. We agree with Imes and Hoyt: These exerciseinduced transient visual events may be related to migraine. Our patient responded to therapy that has been proven useful in migrainous disorders. Joel G. Sacks Frederick J. Samaha University of Cincinnati College of Medicine Cincinnati, Ohio, U. S. A. Acknowledgment: Supported in part by an unrestricted grant to the Department of Ophthalmology, University of Cincinnati College of Medicine, from Research to Prevent Blindness, Inc., New York. REFERENCES 1. Imes RK, Hoyt WF. Exercise- induced transient visual events in young healthy adults. I Clin Neuro Ophthalmol 1989; 9: 178- 80. Elevated Intraocular Pressure in Dural Shunt Syndrome: A Judgment on Exercise To the Editor: There is a high incidence of elevated intraocular pressure in patients with the dural shunt syndrome ( 1,2). Elevated episcleral venous pressure is the most common cause of this problem; angle closure ( 3) is less frequent. A recently examined patient with elevated intraocular pressure ( and open angles) caused by the dural shunt syndrome asked if vigorous exercise would endanger her eye by further elevating the intraocular pressure. She was extremely athletic, playing as many as four or five softball games on a given day. Not knowing how to answer her, we measured her intraocular pressure while she was undergoing maximal physical exertion in the cardiac physiology laboratory. CASE REPORT A 29- year- old woman reported that she developed redness of the left eye in association with conjunctival edema and proptosis 3 years earlier, 1 month after she was hit in the mouth with a softball. Vision was correctable to 20/ 20 in each eye and there was no afferent pupillary defect. The visual fields were normal. The exophthalmometer readings were 16 on the right and 22 on the left. Arteriolization of the left conjunctival vessels was present. The intraocular pressures were 12 mm of mercury in the right eye and 26 in the left. Gonioscopy showed that the angles were open to the ciliary body bilaterally. Ophthalmoscopy showed slight venous distension of the left retinal vessels and there was no pathologic cupping of the optic disc. A 2- week trial of Timoptic 0.5% in the left eye twice daily had no clear- cut effect on the intraocular pressure. Similarly, a drop of Betagan in the left eye did not lower the pressure while she was observed in the office for 1Vz h. Arteriography demonstrated a left carotid dural fistula fed primarily from the external carotid artery branches, with minimal supply from the internal carotid artery. When the risks of therapeutic embolization were discussed with her, she declined to have the procedure performed, hoping for a spontaneous closure of the fistula. METHOD In order to answer the question she raised, the patient was evaluated in the cardiac exercise laboratory. She was placed supine on a table and her feet were attached to a bicycle ergometer. Her pulse was measured on an electrocardiograph, her blood pressure was recorded from a standard cuff over the brachial artery, and her intraocular pressures were determined using a Schiotz tonometer while she was actively exercising. RESULTS The resting values were: pulse, 92; blood pressure, 110/ 76; and intraocular pressure, 12.0 mm of mercury in the right eye and 28.0 in the left. At the end of the exercise period, when she was pedaling at 50 rlmin and performing 125 W of work, the results were as follows: pulse, 160; blood pressure, 150/ 70; and intraocular pressure, 10.9 mm of mercury in the right eye and 35.8 in the left. J Clin Neuro- ophthalmol, Vol. 10, No. 4, 1990 306 LETTERS TO THE EDITOR DISCUSSION We gave her our judgment: Exercise would probably not have a significantly adverse effect on her vision. The maximum elevation in her intraocular pressure was only 8 mm of mercury under an exercise load she could not possibly sustain for more than several minutes at a time. Because the patient so thoroughly enjoys athletic participation, we were not eager to tell her to restrain her activities. We elected to simply follow the course of her visual fields and optic discs, on the assumption that glaucomatous damage could be detected sufficientlyearly. Joel G. Sacks Myron C. Gerson University of Cincinnati College of Medicine Cincinnati, Ohio, U. S. A. REFERENCES 1. Grove AS Jr. The dural shunt syndrome: pathophysiology and clinical course. Ophtfullmology 1984; 90: 31-- 44. 2. Keltner JL, Satterfield D, Dublin AB, et al. Dural and carotid cavernous sinus fistulas: diagnosis, management and complications. Ophtfullmology 1987; 94: 1585- 1600. 3. Fourman S. Acute closed- angle glaucoma after arteriovenous fistulas. Am JOphthalmoI1989; 107: 156- 9. |
