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Dr. Kenneth Alexander and Dr. Jason McAnany article ranked third among the “Top 25 Hottest Articles in Neuroscience” in 2008

Dr. Kenneth Alexander and Dr. Jason McAnanyCo-authors Dr. Kenneth Alexander (left) and Dr. Jason McAnany (center) discuss their recent article that was listed as #3 among the “Top 25 Hottest Articles in Neuroscience” in 2008.

The study investigated the design of conventional letter charts that are used clinically to evaluate vision loss in eye diseases.

Their results showed that standard letters can sometimes provide misleading information about visual dysfunction, and the authors suggested an alternative way of designing letters to improve their diagnostic ability.


Contrast sensitivity for letter optotypes vs. gratings under conditions biased toward parvocellular and magnocellular pathways
Vision Research, Volume 46, Issue 10, May 2006, Pages 1574-1584
McAnany, J.J.; Alexander, K.R.

Abstract: This study examined the extent to which letter optotypes and grating stimuli provide equivalent measures of contrast sensitivity under conditions designed to favor the magnocellular (MC) and parvocellular (PC) pathways. The contrast sensitivity functions (CSFs) of three visually normal observers were measured for Sloan letters and Gabor patches, using steady- and pulsed-pedestal paradigms to bias processing toward MC and PC pathways, respectively. CSFs for Gabor patches were low-pass for the steady-pedestal paradigm and band-pass for the pulsed-pedestal paradigm, in agreement with previous reports. However, CSFs for letters were low-pass for both testing paradigms. CSFs for letters restricted in frequency content by spatial filtering were equivalent to those for Gabor patches for both testing paradigms. Results indicate that conventional letter optotypes can provide a misleading measure of contrast sensitivity, especially under conditions emphasizing the PC pathway. The use of spatially band-pass filtered letters can provide a more appropriate evaluation of spatial contrast sensitivity while maintaining some of the potential advantages of letters.