title: Transient Monocular Vision Loss on Awakening: A Benign Amaurotic Phenomenon.
abstract: Transient monocular vision loss (TMVL) is an alarming symptom owing to potentially serious etiologies such as thromboembolism or giant cell arteritis. Our objective is to describe the phenomenon of TMVL present on awakening, which may represent a distinct and benign entity.
  
  
  
  We performed a retrospective observational case series of 29 patients who experienced TMVL on awakening. Patients who described monocular dimming or blackout of vision were included, and those with blurred vision, concurrent eye pain, and binocular vision loss were excluded. Descriptive statistics were used to summarize the study population.
  
  
  
  Of the 29 patients we studied, 90% (n = 26) were female and 48% had crowded discs (cup-to-disc ratio ≤0.2). The mean age was 45.4 years, although women were significantly younger than men (mean ages 43.4 and 62.7 years, respectively, P = 0.017). Brain magnetic resonance imaging and vascular imaging (magnetic resonance angiography, computed tomographic angiography, or carotid Doppler) were performed in 69% and 55% of cases, respectively, and were uniformly negative. In 14 patients for whom clear follow-up data could be obtained, no medically or visually significant sequelae of this syndrome were found, and 50% experienced resolution of symptoms.
  
  
  
  Evaluation was uniformly negative when patients described waking with isolated vision loss in 1 eye with subsequent resolution, usually in less than 15 minutes. The natural history seems benign with symptoms frequently remitting spontaneously. This visual phenomenon may represent an autoregulatory failure resulting in a supply/demand mismatch during low-light conditions.
authors.affiliation: Department of Neurology (MAB), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts; Department of Ophthalmology and Visual Sciences (WTC, LBD), Kellogg Eye Center, University of Michigan Medical Center, Ann Arbor, Michigan; Department of Ophthalmology (JFR), Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts; Department of Ophthalmology (MSL), University of Minnesota, Minneapolis, Minnesota; Departments of Neurology and Ophthalmology (ERE), Michigan State University, East Lansing, Michigan; and Department of Surgery (NT), Division of Ophthalmology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Bouffard
authors.forename: Wayne T
authors.initials: WT
authors.lastname: Cornblath
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Rizzo
authors.forename: Michael S
authors.initials: MS
authors.lastname: Lee
authors.forename: Lindsey B
authors.initials: LB
authors.lastname: DeLott
authors.forename: Eric R
authors.initials: ER
authors.lastname: Eggenberger
authors.forename: Nurhan
authors.initials: N
authors.lastname: Torun
mesh_terms: D000328:Adult; D000368:Aged; D001766:Blindness / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D012075:Remission, Spontaneous; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D015349:Vision, Monocular; D014792:Visual Acuity; D055815:Young Adult