Send to

Choose Destination
Wilderness Environ Med. 2015 Jun;26(2):200-4. doi: 10.1016/j.wem.2014.10.003. Epub 2015 Feb 26.

An investigation of ultramarathon-associated visual impairment.

Author information

Department of Clinical Ophthalmology, Næstved University Hospital; and the Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark (Dr Høeg).
El Dorado Hills Optometric Center, El Dorado Hills, CA (Dr 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:



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.


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.


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.


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.


corneal edema; physical endurance; refractive surgery; running; visual impairment

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center