Abstract
Purpose:
To assess whether performance on the Smith-Kettlewell Reading (SK-Read) Test is a reliable predictor of handwriting in low vision patients.
Methods:
We performed a prospective cohort study of 31 low vision patients at their initial low vision rehabilitation evaluation. The patients completed all components of a routine low vision appointment including logMAR acuity measurement, performed the SK-Read Test (a non-conextual reading test), and performed a handwriting task. Patients were timed while performing each task and their accuracy was recorded. The handwriting task was performed by having patients write five five-letter words into sets of boxes where each letter is separated by a box. The boxes were 15mm x 15mm and accuracy was scored with 50 points possible from 25 letters - one point for each letter within the confines of a box and 1 point if the letter was legible. The variables reported on are SK-Read errors per block, SK-Read time per block, logMAR acuity, and handwriting task time-to-accuracy ratio. Correlation analysis was performed to examine the association between each pair of variables.
Results:
31 low vision patients participated in the study. Median age was 81.5 years (range: 54-97). 27/31 patients (87%) had ARMD or some other maculopathy while 3/31 patients (13%) had visual impairment from media opacity or neurological impairment. Median Snellen Acuity was 20/152 (range: 20/22-20/1000) and median logMAR acuity was 0.88 (range: 0.04-1.70). SK-Read errors per block correlated with logMAR acuity (r= 0.55, p<< 0.01) and SK-Read time per block correlated with logMAR acuity (r=0.38, p=0.03). SK-Read errors per block correlated with handwriting task time-to-accuracy ratio (r=0.68, p<< 0.01). SK-Read time per block correlated with handwriting task time-to-accuracy ratio (r=0.84, p<<0.01). LogMAR acuity score correlated with handwriting task time-to-accuracy ratio (r=0.35, p=0.053).
Conclusions:
SK-Read may be a more reliable predictor of handwriting performance than logMAR acuity in low vision patients. SK Read difficulty has been associated with presence of central scotomas which may also be associated with difficulty in visually guided motor activity. Further study is warranted to examine the implications of SK-Read performance on vision-related disability in low vision patients.