Effect of the Fresnel membranous prism on the visual function

• Published in: JAPANESE ORTHOPTIC JOURNAL Vol. 36; pp. 85 - 93
• Main Authors: Amano, Daisuke, Oka, Tomoko, Kanayama, Motoko, Asonuma, Sanae, Fujikado, Takashi, Osawa, Yui, Nakamae, Mika, Tsurudome, Yasuhiro, Fujiki, Kaori, Bessho, Kenichiro, Kojima, Yuka, Takada, Yusuke
• Format: Journal Article
• Language: English
• Published: JAPANESE ASSOCIATION OF CERTIFIED ORTHOPTISTS 2007
• Subjects: Contrast sensitivity; Fresnel membrane prism; Glare; Scatter index; Visual acuity
• ISSN: 0387-5172; 1883-9215
• DOI: 10.4263/jorthoptic.36.85

[Purpose] To examine the effect of Fresnel prism on visual function. [Subject and method] 9 eyes of 9 subjects without ocular abnormalities were examined . Age ranged from 21 to 29 years (24.8±3.12, average±SD) and the refraction ranged from +0.5 to -5.0 diopters (-1.47±1.63). Membrane prism was fixed on the full-corrected lens. The power of Fresnel prisms were (1) 6 (2) 8 (3) 10 (4) 12 (5) 15 (6) 20 (7) 30 (Prism, Base out). We tested, 1: Full-corrected visual acuity, 2: Contrast sensitivity (Area Under Log Contrast Sensitivity Function, CSV-1000E), 3: Glare test (CSV1000-HGT) 4: Root Mean Square (μm) value of total ocular aberration (Coma like (C3) aberration, Spherical-like (C4) aberration, C3+C4) and scatter index (SI) by Wavefront analyzer (TOPCON KR-9000PW) 5: Questionnaires of visual quality with prism. [Results] Visual acuity and contrast sensitivity decreased significantly with prism 8Δ or more as compared with no prism (P<0.01). With glare light, contrast sensitivity decreased significantly with prism 12Δ or more compared without prism(P<∼0.05). Contrast sensitivity with glare light decreased significantly with prism 8Δor more compared with it without glare light (P=∼0.05). C3+C4 increased with prism 12Δ and 30Δsignificantly compared without prism (P<0.05). SI increased significantly with prism 12Δ or more(P<0.05). The subjective visual quality decreased with the increase of the power of prism. [Conclusion] When we prescribe Fresnel membrane prisms with a power more than 8Δ, we have to consider the deterioration of visual function such as visual acuity, contrast sensitivity, glare.