Local regression analysis of cognitive influence on low contrast sensitivity testing. A) Correlation between PASAT and CS, B) Correlation between SDMT and CS. Grey lines are from LOESS analysis. Horizontal LOESS lines represent areas with low or no correlation; rising LOESS lines represent areas with correlation between cognitive function and visual function test performance. For better visibility dotted lines separate the areas with an influence (left sides) and without influence (right sides). Data from partial correlations controlling for retinal nerve fibre layer thickness show a similar result (not shown). Abbreviations: LOESS, local regression analysis; CS, low contrast sensitivity; PASAT, paced auditory serial addition test three second version; SDMT, symbol digit modalities test; FACT, functional acuity contrast testing; AUC, area under the log contrast sensitivity function.