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. 1998 Apr;82(4):342–345. doi: 10.1136/bjo.82.4.342

Novel approach towards colour imaging using a scanning laser ophthalmoscope

A Manivannan 1, J Kirkpatrick 1, P Sharp 1, J Forrester 1
PMCID: PMC1722549  PMID: 9640178

Abstract

AIMS—Conventional fundus imaging using a fundus camera produces colour fundus pictures. The scanning laser ophthalmoscope (SLO) has the advantages of lower levels of light exposure, improved contrast, and direct digital imaging but until now has produced monochromatic images as a laser of single wavelength is used. True representation of the fundus is possible by combining images taken using blue, green, and red lasers.
METHODS—A custom built SLO was used to capture blue, green, and red fundus images from suitable volunteers and patients with fundus disease. Images were corrected for eye movement and combined to form a colour image. Colour fundus photographs were taken using a fundus camera for comparison with the SLO image.
RESULTS—The background fundus and retinal vasculature had similar appearances with the two imaging modalities. Internal limiting membrane reflections were prominent with the SLO. Identification of new vessels in the diabetic fundus was easier with the SLO than the colour fundus photographs.
CONCLUSION—A colour SLO offers all the advantages of the present monochromatic imaging system with the added advantage of true colour representation of the fundus.

 Keywords: scanning laser ophthalmoscope; fundus imaging; digital colour fundus images

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Figure 1  .

Figure 1  

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The normal fundus photograph of a healthy 30 year old male volunteer.

Figure 2  .

Figure 2  

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Monochromatic SLO images of the same volunteer taken at (A) 488 nm (blue), (B) 547 nm (green), and (C) 670 nm (red). The blue, green, and red images are combined to show the true colour image (D). Blue wavelengths are good for imaging the internal limiting membrane which is highly reflective at these wavelengths. Green wavelengths show the vessels at their highest contrast as blood is highly absorbed at these wavelengths. Red wavelengths can differentiate the arteries and the veins.

Figure 3  .

Figure 3  

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(A) Fundus photograph and (B) colour SLO image of a patient with angioid streaks.

Figure 4  .

Figure 4  

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Tuft of new vessels temporal to the macula of a diabetic patient imaged with (A) fundus camera and (B) SLO. The new vessel complex appears with greater contrast in the colour SLO image.

Figure 5  .

Figure 5  

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Optic disc drusen images using (A) fundus photography and (B) colour SLO imaging.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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