Variable pupillary responses have been described with carotid-cavernous sinus fistulas. These often are associated with a decrease in visual acuity and attributed to retinal ischemia. We propose a novel pathophysiologic mechanism for changes in pupillary reactivity involving anatomic changes secondary to choroidal effusion.Methods:
To demonstrate proof-of-concept, we investigated 2 consecutive patients with carotid-cavernous sinus fistulas and pupillary disturbances using repeated refractions and anterior segment ultrasound biomicroscopy.Results:
Ultrasound biomicroscopy demonstrated choroidal thickening and ciliary body effusion with forward rotation of the lens–iris diaphragm altering refraction and mechanically limiting iris movements.Conclusions:
Where there are acute elevations in orbital venous pressure causing ciliary body effusion, changes in visual acuity and pupillary abnormalities can be produced by mechanical effects.