Ophthalmic Physiol Opt. 1995 Sep;15(5):481-7.
Optometric correlates of Meares-Irlen syndrome: a matched group study.
Evans BJ, Busby A, Jeanes R, Wilkins AJ.
Institute of Optometry, London, UK.
People who report visual perceptual distortions, typically when reading, that
are alleviated by using coloured filters are described as suffering from 'Meares-Irlen
Syndrome'. A recent double-masked placebo-controlled trial showed that this
condition cannot be solely explained as a placebo effect and that the beneficial
filter is idiosyncratic and sometimes needs to be highly specific. Several
mechanisms have been suggested for Meares-Irlen Syndrome including ocular motor
(binocular and accommodative) anomalies, a sensitivity to patterned stimuli
(pattern glare), and a deficit of the transient visual sub-system. We
investigated these hypotheses by comparing 16 children, who reported the
symptoms described above and who showed a sustained benefit from coloured
filters, with 25 control children who came from the same school and were matched
for age, reading performance and intelligence. The 'Meares-Irlen Syndrome' group
had slightly, but significantly, reduced vergence and accommodative amplitudes
and stereo-acuity; they also demonstrated significantly more pattern glare. The
two groups did not differ significantly in their visual acuities, refractive
error, dissociated or associated heterophoria, AC/A ratio, or ability to
perceive 20 Hz flicker. It appears that certain ocular motor factors are
correlates of Meares-Irlen Syndrome, rather than the primary underlying cause of
the symptoms. The results support the hypothesis that pattern glare may be
involved in the mechanism of Meares-Irlen Syndrome.