Abstract
Purpose :
Individuals with Down syndrome (DS) experience greater difficulty reliably performing visual acuity (VA) tests due to both barriers from intellectual disability and limitations in overall visual quality. This study evaluated the repeatability of logMAR acuity in subjects with and without DS.
Methods :
High contrast photopic logMAR VA was measured in each eye of 13 subjects with DS (mean age: 30; range: 18 - 50) and 15 controls without DS (mean age: 29; range: 23 - 39). For each eye, VA was recorded on 3 separate charts using a method of constant stimuli until 5 letters were missed on each chart using a computer controlled, linearized display. Repeated measures ANOVA was used to compare logMAR group mean differences by eye. Mixed modeling was used to quantify within-subject standard deviation (Sw) for assessing repeatability by group.
Results :
The average logMAR VA in DS subject was ~6 lines worse than the controls (DS: 0.51 ± 0.19; control: -0.09 ± 0.07, p<.0001). There were no significant inter-eye differences in either group (DS: p=0.602, Control: p >0.999). Repeatability was estimated as 0.09 logMAR (4.5 letters) and 0.05 logMAR (2.5 letters) in DS and control eyes, respectively.
Conclusions :
Despite worse acuity in DS eyes, the VA measurements were highly repeatable in both DS eyes and control eyes.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.