Efron Nathan, McCubbin Sophia
Institute of Health and Biomedical Innovation, and School of Optometry, Queensland University of Technology, Kelvin Grove, Australia.
Optom Vis Sci. 2007 Dec;84(12):1082-6. doi: 10.1097/OPX.0b013e31815b9dfc.
To investigate the effect of observation time on the precision of grading the severity of contact lens complications.
Twenty-five optometry students used the Efron Grading Scales for Contact Lens Complications to grade the severity of one image of each of the 16 forms of anterior eye pathology depicted in the Efron scales. This procedure was repeated for observation times of 0.1, 2, and 60 s.
Overall, significantly greater grading precision (smaller standard deviation of mean grades) was demonstrated for longer observation times (p < 0.004); however, certain complications appear to require longer observation times for precise grading. There was a highly significant dependence of the mean grade on image (p < 0.0001), observation time (p < 0.0001), and observation time-image interaction (p < 0.0001).
Overall, a brief viewing time of a few seconds is typically all that is required for precise grading of ocular complications of contact lens wear. Some forms of pathology are more complex and may require more time to grade precisely.
