International Ophthalmology

, Volume 1, Issue 3, pp 175–178 | Cite as

Minimal spot size on the retina formed by the optical system of the eye

  • R. Birngruber
  • E. Drechsel
  • F. Hillenkamp
  • V. -P. Gabel


A knowledge of the quality of the ocular optical system is of primary importance in light- and laser-photocoagulation of the fundus. A study was therefore undertaken to determine the minimal spot size of a Helium-Neon laser focused on the retina of rabbits: freshly enucleated eyes were carefully mounted in a specially designed eye holder. A small hole was then trepanized throug the sclera and neural retina in the macular region. A minimal spot was produced on the retina and the spot size was measured by scanning the intensity distribution of an enlarged image. It was shown that a diffraction limited spot size can be obtained under certain circumstances. The light scattering out of the focus, however, is about fifty percent.


spot size Helium-Neon laser diffraction limited focus focal energy 


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Copyright information

© Dr. W. Junk bv Publishers 1979

Authors and Affiliations

  • R. Birngruber
    • 1
  • E. Drechsel
    • 2
  • F. Hillenkamp
    • 3
  • V. -P. Gabel
    • 2
  1. 1.Gesellschaft für Strahlen- und Umweltforschung mbHNeuherbergB.R.D.
  2. 2.Augenklinik der Universität MünchenMunichB.R.D.
  3. 3.Institut für Biophysik der Universität FrankfurtFrankfurt am MainB.R.D.

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