An investigation of ultramarathon-associated visual impairment.
OBJECTIVE
The purpose of this study was to investigate the characteristics under which ultramarathon-associated visual impairment occurs and to seek to identify its physiological basis and risk factors.


METHODS
Through an online questionnaire, distributed worldwide, we obtained information from 173 self-identified ultramarathon runners who had experienced visual impairment during an ultramarathon. We attempted to characterize this vision impairment-its symptoms, duration, and the conditions under which it occurs. Select characteristics were compared with a reference group of 412 registrants of the 161-km Western States Endurance Run.


RESULTS
Ultramarathon-associated visual impairment was typically characterized as painless clouding of vision that resolved either during (13.5%) or after racing within a median of 3.5 hours (range 0 to 48 hours) upon cessation of running. The mean (±SD) distance at which vision impairment occurred was 73±40 km, and the 161-km distance was the most frequent race distance (46.8%) in which visual impairment occurred. Visual impairment was often recurrent, with respondents reporting having it develop during a median of 2 races. Respondents with a history of refractive surgery had more episodes than those without such history (median 3.5 vs 2 episodes, P=.010). Compared with the reference group, runners with visual impairment were nearly twice as likely (23.7% vs 12.1%, P<.001) to have had refractive surgery.


CONCLUSIONS
Ultramarathon-associated visual impairment typically presents as a painless clouding of vision that is self-limited but tends to recur in certain runners. Risk appears higher among those with a history of refractive surgery, which is relevant for ultramarathon runners who are considering, or who have a history of, refractive surgery.
Department of Clinical Ophthalmology, Næstved University Hospital; and the Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (Dr Høeg).
Tracy B
TB
Høeg
El Dorado Hills Optometric Center, El Dorado Hills, CA (Dr Corrigan).
Genevieve K
GK
Corrigan
Department of Physical Medicine and Rehabilitation, Department of Veterans Affairs, Northern California Health Care System; and University of California Davis Medical Center, Sacramento, CA (Dr Hoffman). Electronic address: mdhoffman@ucdavis.edu.
Martin D
MD
Hoffman
D000328:Adult; D003625:Data Collection; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012420:Running; D013177:Sports; D011795:Surveys and Questionnaires; D014786:Vision Disorders / Q000473:pathology*
corneal edema; physical endurance; refractive surgery; running; visual impairment