Clinical predictors of the optimal spectacle correction for comfort performing desktop tasks.
BACKGROUND
The best strategy for spectacle correction of presbyopia for near tasks has not been determined.


METHODS
Thirty volunteers over the age of 40 years were tested for subjective accommodative amplitude, pupillary size, fusional vergence, interpupillary distance, arm length, preferred working distance, near and far visual acuity and preferred reading correction in the phoropter and trial frames. Subjects performed near tasks (reading, writing and counting change) using various spectacle correction strengths. Predictors of the correction maximising near task comfort were determined by multivariable linear regression.


RESULTS
The mean age was 54.9 years (range 43 to 71) and 40 per cent had diabetes. Significant predictors of the most comfortable addition in univariate analyses were age (p<0.001), interpupillary distance (p=0.02), fusional vergence amplitude (p=0.02), distance visual acuity in the worse eye (p=0.01), vision at 40 cm in the worse eye with distance correction (p=0.01), duration of diabetes (p=0.01), and the preferred correction to read at 40 cm with the phoropter (p=0.002) or trial frames (p<0.001). Target distance selected wearing trial frames (in dioptres), arm length, and accommodative amplitude were not significant predictors (p>0.15). The preferred addition wearing trial frames holding a reading target at a distance selected by the patient was the only independent predictor. Excluding this variable, distance visual acuity was predictive independent of age or near vision wearing distance correction. The distance selected for task performance was predicted by vision wearing distance correction at near and at distance.


CONCLUSIONS
Multivariable linear regression can be used to generate tables based on distance visual acuity and age or near vision wearing distance correction to determine tentative near spectacle addition. Final spectacle correction for desktop tasks can be estimated by subjective refraction with trial frames.
Department of Ophthalmology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond VA 23298-0438, USA. cleffler@pol.net
Christopher T
CT
Leffler
Byrd
B
Davenport
Jodi
J
Rentz
Amy
A
Miller
William
W
Benson
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D017060:Patient Satisfaction; D017755:Prosthesis Fitting; D011932:Reading; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000628:therapy*; D012044:Regression Analysis; D013647:Task Performance and Analysis; D014792:Visual Acuity / Q000502:physiology; D014956:Writing