July 1993
Volume 34, Issue 8
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Articles  |   July 1993
Possible errors in the measurement of retinal lesions.
Author Affiliations
  • J V Arnold
    Cardiac Surgery Unit, Royal Postgraduate Medical School, London, United Kingdom.
  • J W Gates
    Cardiac Surgery Unit, Royal Postgraduate Medical School, London, United Kingdom.
  • K M Taylor
    Cardiac Surgery Unit, Royal Postgraduate Medical School, London, United Kingdom.
Investigative Ophthalmology & Visual Science July 1993, Vol.34, 2576-2580. doi:
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    • Get Citation

      J V Arnold, J W Gates, K M Taylor; Possible errors in the measurement of retinal lesions.. Invest. Ophthalmol. Vis. Sci. 1993;34(8):2576-2580.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

PURPOSE: To determine the accuracy of the measurement of structure in the retina from fundus photographs. METHOD: A model eye was developed to measure the retinal image size of the Zeiss fundus camera. A x 10 microscope objective with a focal length of 16.41 mm was used together with a microscope graticule. RESULTS: Under emmetropic conditions the difference between the calculated and the measured magnification was 8.6%. The total change in magnification from myopia to hyperopia was -24.63% to +18.1%. When the camera position was altered with respect to the model eye by +/- 5 mm under myopic conditions the change in magnification was -4.5% and +6.8%. In the hyperopic condition the change was -5.6% to +4.6%. CONCLUSIONS: Measuring the size of structure in the retina from photographs may therefore prove to be inaccurate but in some circumstances determining the percentage change in size may prove more reliable.

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