Multispectral imaging of the ocular fundus using light emitting diode illumination

N.L. Everdell, I.B. Styles, Antonio Calcagni, Jonathan Gibson, J. Hebden, E. Claridge

Research output: Contribution to journalArticlepeer-review


We present an imaging system based on light emitting diode (LED) illumination that produces multispectral optical images of the human ocular fundus. It uses a conventional fundus camera equipped with a high power LED light source and a highly sensitive electron-multiplying charge coupled device camera. It is able to take pictures at a series of wavelengths in rapid succession at short exposure times, thereby eliminating the image shift introduced by natural eye movements (saccades). In contrast with snapshot systems the images retain full spatial resolution. The system is not suitable for applications where the full spectral resolution is required as it uses discrete wavebands for illumination. This is not a problem in retinal imaging where the use of selected wavelengths is common. The modular nature of the light source allows new wavelengths to be introduced easily and at low cost. The use of wavelength-specific LEDs as a source is preferable to white light illumination and subsequent filtering of the remitted light as it minimizes the total light exposure of the subject. The system is controlled via a graphical user interface that enables flexible control of intensity, duration, and sequencing of sources in synchrony with the camera. Our initial experiments indicate that the system can acquire multispectral image sequences of the human retina at exposure times of 0.05 s in the range of 500-620 nm with mean signal to noise ratio of 17 dB (min 11, std 4.5), making it suitable for quantitative analysis with application to the diagnosis and screening of eye diseases such as diabetic retinopathy and age-related macular degeneration.
Original languageEnglish
Article number093706
Number of pages9
JournalReview of scientific instruments
Issue number9
Publication statusPublished - 29 Sept 2010

Bibliographical note

Copyright © 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Review of Scientific Instruments 81, 093706 (2010) and may be found at


  • female
  • fundus oculi
  • humans
  • lighting
  • male
  • molecular imaging
  • semiconductors
  • spectrum analysis


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