Purchase this article with an account.
Nazlee Zebardast, Sheila West, Beatriz Munoz, Pradeep Ramulu; Comparing the Impact of Refractive and Non-Refractive Vision Loss on Disability. Invest. Ophthalmol. Vis. Sci. 2013;54(15):5312.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To compare the effects of uncorrected refractive error (URE) and non-refractive visual impairment (VI) on disability measures.
Cross-sectional study using data from first round of the Salisbury Eye Evaluation. 2469 individuals with binocular presenting visual acuity (PVA) of 20/80 or better were included. URE was defined as binocular PVA of 20/30 or worse, improving to better than 20/30 with subjective refraction. VI was defined as post-refraction best corrected visual acuity (BCVA) of 20/30 or worse. Visual acuity (VA) decrement due to VI was calculated as the difference between BCVA and 20/30 while that due to URE was taken as the difference between PVA and BCVA. Multivariable regression analyses were used to assess the disability impact of: 1) vision status using the group with normal vision as reference and 2) one-line decrement in acuity due to VI and URE. The main outcome measures were objective measures of visual function obtained from timed performance of mobility and near vision tasks, self-reported driving cessation, and self-reported visual disability measured by the Activities of Daily Vision (ADV) scale.
Compared to individuals with normal vision, subjects with VI (n=191) demonstrated a significant decline in all objective and subjective metrics of visual function (p<0.05) while subjects with URE (n=142) demonstrated slower walking speeds, slower near task performance, more frequent driving cessation, and lower ADV scores, but did not demonstrate slower stair climbing or descent speed. For all disability metrics evaluated, the magnitude of the performance decrement was consistently greater in subjects with VI than in individuals with URE (Fig 1). A one-line decrement in VA due to VI was associated with slower completion of stair climb and descent tasks, greater odds of driving cessation, and greater difficulty in self-reported visual function when compared to a one-line VA decrement due to URE (Fig 2).
VI is associated with greater disability than URE across a wide variety of functional measures, even in analyses adjusting for the severity of vision loss. Refractive and non-refractive vision loss should be distinguished in studies evaluating visual disability and should be understood to have differing consequences.
This PDF is available to Subscribers Only