The effect of Fresnel prisms on dynamic visual acuity

Gail Maconachie, Helen Griffiths, David Buckley
2010 British and Irish Orthoptic Journal  
word count = 256 words Total words excluding references = 2489 Abstract Aims This study aims to determine any differences in visual acuity (VA) and contrast sensitivity (CS) between 3M Fresnel prisms and Trusetal prisms foils. Methods Sixteen participants (mean age 20 years) with normal VA and CS were recruited. The effect of 5, 10, 20 and 30 prism strengths on monocular VA and CS was assessed using a Bailey Lovie logMAR chart, and Pelli-Robson chart respectively. This was repeated for both
more » ... s repeated for both 3M Fresnel prisms and Trusetal prism foils. Results Deterioration in VA and CS was evident with increasing prism strength with both prism types. VA was more significantly reduced with the 3M Fresnel prism than the Trusetal Fresnel prism [F 1, 15 = 19.63, p < 0.001]. There was also significant difference between the prism types with prism strength [F 3, 45 = 10.35, p = < 0.0001]. This resulted from a larger reduction in VA with 30  3M Fresnel prisms where mean VA with 3M Fresnel prism was 0.70 logMAR, compared to 0.57 logMAR with 30 
doi:10.22599/bioj.26 fatcat:zzi5iubs2vcxvkdr2oqd5etvq4