Tiffany Wardle & Miguel Sousa Memorial Liveblogging™ of a presentation at ATypI Brighton 2007 (q.v.)
(First slide credits everything to Kevlar and to James Sheedy, Pacific University, College of Optometry.)
The team I work in is multidisciplinary and combines knowledge from typographic experts, scientific experts, and engineering experts. The majority of the research was carried out by Jim Sheedy.
Eye fatigue is a problem. Survey of 4,068 computer workers: 40.5% experienced eye fatigue. (Done via a questionnaire: I get blurred vision; I close one eye when reading; I skip or repeat lines when reading; print starts to look blurry after I read for a while.) (At this point, Miguel Sousa gets up and walks away from my horridly invasive typing. Isn’t he married to Tiffany Wardle?)
What is eye fatigue? What are the muscles that are involved? (Compares against weightlifters.) (Shows Neu-Vitra Oculizer, with suction cups to pull and push and turn your own eye! Mentions eye exercises.) (Shows slide of research from 1947 with 40 participants reading six hours each twice. Produced 16-mile-long paper trail. Reading speed and regressive eye movements were nearly the same. Blink rate increased slightly from nine to 11 on average per minute. But other research from 1993 shows that we blink 22/min while just talking, 10 while reading a book, 7 on computer. Blinking is greatly suppressed while reading.)
(Another slide shows is is harder to move a fixation forward after a saccade and there are more regressive fixations. That data came from computer screens. Blinking slows reading.)
(One suggestion is that the six muscles around the eye are not involved in fatigue. The orbicularis oculi might be, as it is responsible for squinting and blinking.)
(Five minutes of stressful reading: Glare, small font [8 point], low contrast, convergence error [too close], accommodative error [switching between nearsighted and farsighted], refractive error [blur, like astigmatism]. Convergence and accommodate produced increases in activity that aren’t statistically reliable. Glare and refractive: Very large increases in squinting. So yes, the orbicularis is definitely involved. But in another study, forcing people to squint improved acuity. So there are good physiological reasons to squint.)
(Yet another study showed that glare and refractive error caused significant orbicularis activation.)
We’re thinking there are three distinct problems. Eye disorders like accommodation and convergence (not enough squinting); environmental (low contrast, small font (same, plus decreased blinking); refractive error and glare (an odd grouping; more squinting and blinking).
Eye exercises are completely worthless (because they exercise the muscles around the eye that aren’t involved in fatigue).
(Q. from me with this answer: Only text size and contrast relate to typography and are under typographers’ control. Many other very solid questions untranscribed.)