Optometry - Journal of the American Optometric Association
Volume 75, Issue 8 , Pages 509-516, August 2004

Contrast sensitivity through hybrid diffractive, Fresnel, and refractive prisms

  • Milton Katz, O.D.

      Affiliations

    • Katz M. Contrast sensitivity through hybrid diffractive, Fresnel and refractive prisms. Optometry 2004;75:509-16.
    • Corresponding Author InformationCorresponding address: State University of New York, College of Optometry, 33 West 42nd Street, New York, New York 10036.

State University of New York, College of Optometry, New York, New York

Article Outline

Background

Fresnel and wedge-shaped refractive prisms are used diagnostically and therapeutically in clinical practice. This article extends the study on the effect of prisms on visual acuity to the effect on contrast sensitivity by membrane Fresnel (F), refractive (R), and newly designed hybrid diffractive (C) prisms (ComPrisms™), which combine a wedge-shaped refractive prism with a diffractive element.

Methods Vistech contrast sensitivity function (CSF) Charts A, B, and C were used to measure the monocular and binocular contrast sensitivity of 21 and 20 subjects, respectively. CSF was measured without prisms (U), through the hybrid diffractive prisms, membrane Fresnel prisms, and acrylic refractive prisms in powers of 20A, 30A, and 40A.

Results

Repeated measures analysis of variance calculations resulted in significant main effects in contrast sensitivity across prism types, prism powers, and between monocular and binocular measurements. Results of the Scheffé test for all possible contrast sensitivity comparisons between spatial frequencies are provided. It was found that as prism power increased from 20A to 40A, the rate of reduction in area under the CSF curve of ComPrisms became half that of the refractive and Fresnel prisms.

Conclusions

Although all three prism types reduced contrast sensitivity with respect to the unaided condition, the ComPrisms at all powers provided significantly better contrast sensitivity than the refractive or Fresnel prisms of equivalent power. Significant binocular summations in contrast sensitivity were found without prisms and across all prism types and powers.

Key words: ComPrisms, contrast sensitivity, Fresnel prisms, hybrid diffractive optics, ophthalmic prisms, refractive prisms

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References 

  1. Katz M. Visual acuity through Fresnel, refractive, and hybrid diffractive/refractive prisms. Optometry. 2004;75:503–508
  2. Woo GC, Campbell FW, Ing B. Effect of Fresnel prism dispersion on contrast sensitivity function. Ophthalmol Physiol Opt. 1986;48:415–418
  3. Cotter SA, London R. Clinical uses of prism. 68. Mosby Year-Book, Inc; 1995;69
  4. Sweatt WC. Describing holographic optical elements as lenses. J Opt Soc Am. 1977;67:803–808
  5. Filtron brand manufactured by Gentex Corp., Carbondale, Pennsylvania 18407.
  6. Ginsburg AP. Spatial frequency and contrast sensitivity chart. U.S. Patent No. 4,365,873, 1982.
  7. Applegate RA, Hilmantel G, Howland HC, et al. Corneal first surface optical aberrations and visual performance. J Refract Surg. 2000;16:507–514
  8. Marcos S. Aberrations and visual performance following standard laser vision correction. J Refract Surg. 2001;17:S596–S601
  9. Pardhan S, Gilchrist J. The effect of monocular defocus on binocular contrast sensitivity. Ophthalmol Physiol Opt. 1990;10:33–36
  10. Rabin J. Two eyes are better than one: Binocular enhancement in the contrast domain. Ophthalmol Physiol Opt. 1995;15:45–48

PII: S1529-1839(04)70176-1

doi:10.1016/S1529-1839(04)70176-1

Optometry - Journal of the American Optometric Association
Volume 75, Issue 8 , Pages 509-516, August 2004

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