Cylindrical lens

A cylindrical lens is a lens which focuses light into a line instead of a point, as a spherical lens would. The curved face or faces of a cylindrical lens are sections of a cylinder, and focus the image passing through it into a line parallel to the intersection of the surface of the lens and a plane tangent to it. The lens compresses the image in the direction perpendicular to this line, and leaves it unaltered in the direction parallel to it (in the tangent plane).

Cylindrical lenses.

A toric lens combines the effect of a cylindrical lens with that of an ordinary spherical lens.

Uses

Uses in Ophthalmology
  • Cylindrical lenses are prescribed to correct astigmatism.[1]
  • Cross cylinder, which is a combination of two cylindrical lenses with equal strength and opposite power, is used in subjective refraction for discovering astigmatism, assessing strength and axis of the astigmatic power etc.[2]
  • Maddox rod made up of parallelly arranged cylindrical lenses are used to detect Strabismus and diplopia.[3]

Other uses
  • In a light sheet microscope, a cylindrical lens is placed in front of the illumination objective to create the light sheet used for imaging.
  • Cylindrcal lenses are used in optical spectrometers.[4]
  • Cylindrcal lenses are used in holography.[5]
  • Doublet cylinder lens system is used in optical coherence tomography.[6]
  • Cylinder lenses are used in many laser applications also. Cylindrical lens can be used to create a laser line. Doublet cylinder lens is used to make laser sheets and circularize elliptical beams from laser diodes.[7]
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See also

References
  1. Khurana, AK. "Light and optics". Theory and practice of optics and refraction (2nd ed.). Elsevier. p. 24. ISBN 978-81-312-1132-8.
  2. "Jacksons Cross Cylinder (JCC)" (PDF). Journal of Kerala Society of Ophthalmic Surgeons.
  3. "Dissimilar Image Tests". www.aao.org.
  4. Fu, Xiao; Duan, Fajie; Jiang, Jiajia; Huang, Tingting; Ma, Ling; Lv, Changrong (1 October 2017). "Astigmatism-corrected echelle spectrometer using an off-the-shelf cylindrical lens". Applied Optics. 56 (28): 7861–7868. doi:10.1364/AO.56.007861. ISSN 2155-3165.
  5. Xiao, Dan; Wei, Rong; Liu, Su-Juan; Wang, Qiong-Hua (1 December 2018). "Holographic magnification system based on cylindrical lens". Optik. 174: 707–714. doi:10.1016/j.ijleo.2018.06.103. ISSN 0030-4026.
  6. "Fast Tomography Imaging System for Material Surface Based on Doublet-cylinder-lens in Intelligent OCT".
  7. "Cylinder Lens | Edmund Optics". www.edmundoptics.com.

Other Sources
  • Jacobs, Donald H. Fundamentals of Optical Engineering. MC Graw-Hill Book Co., 1943.
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