Visual Sequential Memory and the Effect of Luminance Contrast

Jason S. Ng, OD, PhD

 Background: Standard visual acuity using reverse contrast (white-on-black) has been shown to be significantly better than standard contrast (black-on-white). We examined whether differences in luminance contrast would have any effect on a visual sequential memory task.

Methods: Forty-two subjects (23 males, 19 females) performed two tests of visual sequential memory specifically designed for this study. Each test had 16 questions. One test was presented in standard contrast and another was presented in reverse contrast. All of the test stimuli were well above visual acuity thresholds. Subjects were free from ocular pathologies, had visual acuities of 0.1 logMAR or better, and the majority (81%) were completely naïve to the standard clinical test of visual sequential memory, which is given in standard contrast. The raw scores (number correct) of each test were compared using an unpaired t-test.

Results: A significant order effect was observed, and thus, subjects’ scores on the first test performed was the outcome measure analyzed. The mean scores were 11.6 [95% CI: 10.8-12.4] and 12.9 [95% CI: 11.9-13.9] for the standard and reverse contrast tests, respectively. Subjects performed significantly (p < 0.05) better (8.3% improvement) when the test was presented in reverse contrast versus standard contrast.

Conclusions: Reverse contrast presentation of stimuli yields a statistically significant improvement in visual sequential memory. The findings could play an important clinical role in the determination of optimal print contrast for some patients.


Keywords: contrast, memory, polarity, visual memory, visual perceptual processing, visual sequential memory