Prevalence of refractive errors on a VOSH mission to Nicaragua.

Background: Optometric services in many parts of the world are unavailable with a resultant lack of information on the epidemiology of visual problems in those countries as well.
Methods: A retrospective analysis was conducted on the records of 3,281 patients seen on a VOSH mission to Nicaragua.
Results: The mean spherical correction for each eye was a low hyperopic correction. For eyes having an astigmatism the mean cylinder correction was -1.00 and was usually oriented against the rule.
Conclusion: There was a lower incidence of myopia in this population than for many others that have been studied. There was also a need for a presbyopic correction at an earlier age than for Mid-European populations. A very large number of spectacles must be donated in order to get a sufficient supply for a successful VOSH mission.