Uniformity of visual acuity measures in published studies.
OBJECTIVE
To investigate the methods used in contemporary ophthalmic literature to designate visual acuity (VA).


METHODS
Papers in all 2005 editions of five ophthalmic journals were considered. Papers were included if (1) VA, vision, or visual function was mentioned in the abstract and (2) if the study involved age-related macular degeneration, cataract, or refractive surgery. If a paper was selected on the basis of its abstract, the full text of the paper was examined for information on the method of refractive correction during VA testing, type of chart used to measure VA, specifics concerning chart features, testing protocols, and data analysis and means of expressing VA in results.


RESULTS
One hundred twenty-eight papers were included. The most common type of charts used were described as logMAR-based. Although most (89.8%) of the studies reported on the method of refractive correction during VA testing, only 58.6% gave the chart design, and less than 12% gave any information whatsoever on chart features or measurement procedures used.


CONCLUSIONS
The methods used and the approach to analysis were rarely described in sufficient detail to allow others to replicate the study being reported. Sufficient detail should be given on VA measurement to enable others to duplicate the research. The authors suggest that charts adhering to Bailey-Lovie design principles always be used to measure vision in prospective studies and their use encouraged in clinical settings. The distinction between the terms logMAR, an acuity notation, and Bailey-Lovie or ETDRS as chart types should be adhered to more strictly.
Williams
Michael A
MA
Department of Geriatric Medicine, Queen's University of Belfast, Belfast, Northern Ireland, United Kingdom. mikewilliams99@hotmail.com
Moutray
Tanya N
TN
Jackson
A Jonathan
AJ
D002386:Cataract / Q000503:physiopathology; D003625:Data Collection; D006801:Humans; D008268:Macular Degeneration / Q000503:physiopathology; D009885:Ophthalmology / Q000592:standards*; D010506:Periodicals as Topic; D011643:Publishing / Q000592:standards*; D012030:Refractive Errors / Q000503:physiopathology; D014787:Vision Tests / Q000592:standards*; D014792:Visual Acuity / Q000502:physiology*