Purpose: To investigate the impact of graphical user interface screen features on computer task performance in patients with age-related macular degeneration (AMD).
Design: Interventional case series.
Methods: Eighteen patients with visual impairment due to AMD were recruited from the Bascom Palmer Eye Institute Low Vision Clinic. Each patient underwent evaluation of visual acuity using the Early Treatment Diabetic Retinopathy Study protocol, contrast sensitivity using a Pelli-Robson chart, binocular simultaneous visual field using the Esterman program on an automated perimeter, and color vision using Farnsworth D-15. Each subject then completed computer icon identification tasks while the following screen features of the graphical user interface were varied: size of icons displayed, icon set size (number of icons displayed), and background color. Each patient performed all 125 computer tasks with each of five icon sizes (9.2 mm, 14.6 mm, 23.2 mm, 36.8 mm, 58.3 mm), each of five icon set sizes (2, 3, 4, 5, 6), and each of five different background colors (black, white, red, green, blue) in a randomly ordered fashion. Relationships between computer task performance (accuracy and speed) and graphical user interface screen features were studied.
Results: Icon size and icon set size are significantly associated with computer task accuracy (P <.001), whereas background color is not a significant predictor of task accuracy (P =.63). The impact of icon size on accuracy is nonlinear, with the data indicating that no additional improvement in accuracy is associated with increasing the icon size beyond 23.2 mm. The impact of icon set size on accuracy is linear, with a smaller icon set size significantly associated with greater computer accuracy. A larger icon size is significantly associated with a shorter time to task completion (P =.001); this relationship is largely linearly related to icon size. There was no significant impact of background color (P =.11) or set size (P =.37) on time to task completion.
Conclusions: Modifications of graphical user interface design may permit improved computer task performance among patients with visual impairment due to AMD.