Reading eye movements among homonymous hemianopia.

Purpose: To measure the reading eye movement's parameters and quantify the oculomotor dysfunction among subjects with homonymous hemianopia compared to age-matched controls using ReadAlyzer.

Methods: This was a prospective study carried out in the neuro-optometry clinic of a tertiary eye care hospital in South India, from October 2018 to Janurary 2019. Fifty consecutive patients diagnosed with homonymous hemianopia were enrolled in the study after obtaining their written informed consent. Reading eye movements were measured using ReadAlyzer in patients with homonymous hemianopia and age-matched controls. Reading eye movement parameters were represented in median [interquartile range (IQR)].

Results: Subjects with homonymous hemianopia showed increased number of fixations/100 words- median (IQR) [175 (80-270)] compared to controls [91 (52.5-127.5)]; increased number of regressions/100 words [33 (-13-79)] compared to controls [18 (-10-46)]; and reduced reading rate [93 (46-140) words/min] compared to controls [186 (144-228) words/min] (Mann-Whitney U test, P ≤ 0.05). Similar trend was observed for grade level equivalent 2 (0-4) and regression to fixation ratio 15 (1-29) compared to controls [grade equivalent 7 (3-11) and regression to fixation ratio 11 (-2-24)] (Mann-Whitney U test, P ≤ 0.005).

Conclusion: Reading eye movements assessed using ReadAlyzer are found to be significantly impaired among homonymous hemianopias compared to age-matched controls (Mann-Whitney U test, P ≤ 0.05).