Slow reading is a result of poor seeing circumstances brought on by visual impairments or natural settings. For a study, researchers comprehensively examined how deteriorated seeing circumstances in terms of spatial resolution, contrast, and background brightness impact eye movement patterns while reading. 

Binocular eye movements were recorded from 14 young, normally sighted people using a high-speed eye tracker. Text blur (severe blur to no blur), text contrast (2.6%–100%), and background brightness (1.3-265 cd/m2) in varied intensities were used to modify images of text passages. In addition, key eye movement characteristics, including saccades, microsaccades, regressive saccades, fixations, and return sweeps, were examined about changes in viewing circumstances. The range of backdrop luminance levels evaluated showed no discernible alterations. 

However, they found a substantial drop in saccade amplitude & velocity with increasing text blur & decreasing text contrast, as well as a significant increase in fixation time, number of fixations, the proportion of regressive saccades, microsaccade rate, & duration of return-sweeps. All things considered, reading speed was shown to be most significantly influenced by saccade amplitude, fixation time, and a fraction of regressive saccades, which combined accounted for 90% of the variance. 

Together, the findings demonstrated that reading-related eye movement patterns were changed when viewing circumstances were poor. The results implied that the apparent deviations in eye movements seen in people with visual impairments might be partially the consequence of active and effective information-gathering techniques used when visual sensory input is severely depleted.

Reference: jov.arvojournals.org/article.aspx?articleid=2783624