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Jessica Gustavsson, Baskar Theagarayan; Effect of correcting associated phoria on reading speed. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5422.
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© ARVO (1962-2015); The Authors (2016-present)
The purpose of this study was to investigate the effect of correcting associated phoria at 40 cm on reading speed.
A total of 41 participants were enrolled in this study. All the participants were aged between 18 and 39 years old. They were divided in to two groups, a test group and a control group. Participants whose associated phoria was ≥1Δ were included in the test group (n = 19) and participants whose associated phoria was ≤1Δ were included in the control group (n = 22). All of them had atleast 120 seconds of arc of stereopsis and visual acuity of 20/20 or better. Binocular vision tests including associated phoria, dissociated phoria and fusional reserves were measured with participants’ full correction. All the participants were asked to fill out a symptom questionnaire (Convergence Insufficiency Symptom Survey) to determine how much symptoms they had. Participants’ reading speed was measured using a Rate of Reading test. In the test group the reading speed was measured twice, first without any prisms and then with their associated phoria values (aligning prism). In the control group the reading speed was measured only once with out any prisms. All the participants were asked to read a novel for 10 minutes at 20 cm distance. The rate of reading test was repeated after 10 minutes of reading in both the groups.
The mean baseline reading speed in the test group was 155 ± 25 words/min without any prisms and with aligning prism was 164 ± 16 words/min whereas in the control group it was 148 ± 27 words/min. After 10 min of reading, the reading speed reduced to 146 ± 26 words/min without any prims and to 158 ± 26 words/min with aligning prism in the test group whereas in the control group it remained unchanged (148 ± 21 words/min). This reduction was statistically significant (p<0.001) in the test group. Significant differences were found between the groups in both the dissociated phorias and symptom survey points.
In the test group the reading speed improved by 9 words/min at baseline and 12 words/min after the reading task when they were asked to read with the aligning prism. However, no statistical significant correlation was found between participants’ associated phoria and reading speed.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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