Chapter 4 Transient Monocular Visual Loss

Abstract

Publisher Summary This chapter discusses transient monocular visual loss (TMVL) that is an acute and temporary visual loss in one eye. In most cases of TMVL, the underlying mechanism is the arterial ischemia of the retina or optic nerve. However, numerous other ocular disorders may produce episodes of reversible monocular visual loss and can be easily ruled out by a careful ophthalmologic examination. Ocular disorders changing the patient's refractive error and alterations in corneal properties or in transparency of the anterior chamber often produce episodes of blurry vision that may last from a few seconds to a few hours. Sudden elevations in intraocular pressure may also produce acute monocular visual loss with or without ocular pain, often preceded or associated with halos around lights. Another important cause of TMVL is a swollen or congenitally anomalous optic disc, which may pinch off its own ciliary blood supply or the central retinal artery. In such cases, the episodes of TMVL last only seconds, occur frequently during the day, and are often provoked by changing gaze position or, more commonly, by assuming the upright posture (orthostatic TMVL). These brief episodes of visual loss are called “transient visual obscurations.” Orbital tumors may intermittently compress the ophthalmic or central retinal artery, thereby producing brief gaze-evoked TMVL. Rarely, TMVL may arise from impending occlusion of the central retinal vein.