OPTOMETRIC CORRELATES OF MEARES-IRLEN SYNDROME - A MATCHED GROUP-STUDY

People who report visual perceptual distortions, typically when readin g, that are alleviated by using coloured filters are described as suff ering from 'Meares-Irlen Syndrome'. A recent double-masked placebo-con trolled 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 su ggested for Meares-Irlen Syndrome including ocular motor (binocular an d accommodative) anomalies, a sensitivity to patterned stimuli (patter n glare), and a deficit of the transient visual sub-system. We investi gated these hypotheses by comparing 16 children, who reported the symp toms described above and who showed a sustained benefit from coloured filters, with 25 control children who came from the same school and we re matched for age, reading performance and intelligence. The 'Meares- Irlen Syndrome' group had slightly, but significantly, reduced vergenc e and accommodative amplitudes and stereo-acuity; they also demonstrat ed significantly more pattern glare. The two groups did not differ sig nificantly in their visual acuities, refractive error, dissociated or associated heterophoria, AC/A ratio, or ability to perceive 20 Hz flic ker. It appears that certain ocular motor factors are correlates of Me ares-Irlen Syndrome, rather than the primary underlying cause of the s ymptoms. The results support the hypothesis that pattern glare may be involved in the mechanism of Meares-Irlen Syndrome.