The Effect of Induced Vertical Prism on Reading Related Parameters in Normal Subjects

Title The Effect of Induced Vertical Prism on Reading Related Parameters in Normal Subjects
Author, Co-Author Vandana Rajaram, Andrea Shank, Samantha Gagnon
Topic Binocular Vision/Pediatrics
Program Number
Ballroom A-B
Ferris State University
Abstract Purpose: We objectively evaluated the effect of induced vertical prism on reading efficiency, speed and comprehension in normal adults with no history of reading deficits.

 Methods: Subjects (N=46) in the age range 21-30 years were included. The Visagraph III eye movement recording system was used to objectively measure the following reading related parameters i) Fixations, ii) Regressions, iii) Speed, iv) Comprehension, v) Grade Level Efficiency (GLE).  Baseline measurements were repeated with induced vertical prism of strengths of 1 Prism Diopter (PD), 2PD and 3PD. Any pre-existing vertical phorias were neutralized with prisms prior to testing.

Results: Means of each reading parameter, for different prism strengths were analyzed with a single factor Analysis of Variance (ANOVA). The results were statistically significant for Fixations (F (3,46) = 4.63, p = 0.003), Comprehension (F (3,46) = 3.37, p = 0.019) and GLE (F (3,46) = 4.68, p = 0.003) and non-significant for Regressions (F (3,46) = 2.39, p = 0.06) and Speed (F (3,46) = 1.04, p = 0.37).

Conclusion: Under the conditions tested, we found that induced vertical prism significantly impacts several crucial parameters related to reading in normal subjects. These results may have significant clinical implications for the correction of vertical phorias to enhance reading performance in subjects with reading deficits.  Finally, our findings were not consistent with the literature and require further research.
Affiliation of Co-Authors Ferris State University, Ferris State University