Simultaneous three wavelength imaging with a scanning laser ophthalmoscope.
BACKGROUND
Various imaging properties of scanning laser ophthalmoscopes (SLO) such as contrast or depth discrimination, are superior to those of the traditional photographic fundus camera. However, most SLO are monochromatic whereas photographic systems produce colour images, which inherently contain information over a broad wavelength range.


METHODS
An SLO system has been modified to allow simultaneous three channel imaging. Laser light sources in the visible and infrared spectrum were concurrently launched into the system. Using different wavelength triads, digital fundus images were acquired at high frame rates.


RESULTS
Favourable wavelengths combinations were established and high contrast, true (red, green, blue) or false (red, green, infrared) colour images of the retina were recorded. The monochromatic frames which form the colour image exhibit improved distinctness of different retinal structures such as the nerve fibre layer, the blood vessels, and the choroid.


CONCLUSIONS
A multi-channel SLO combines the advantageous imaging properties of a tunable, monochrome SLO with the benefits and convenience of colour ophthalmoscopy. The options to modify parameters such as wavelength, intensity, gain, beam profile, aperture sizes, independently for every channel assign a high degree of versatility to the system.
Reinholz
F
F
Lions Eye Institute, Perth, and Centre of Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Australia.
Ashman
R A
RA
Eikelboom
R H
RH
D003116:Color; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007259:Infrared Rays; D007834:Lasers; D008297:Male; D019721:Ophthalmoscopes; D009887:Ophthalmoscopy / Q000379:methods*; D010784:Photomicrography / Q000295:instrumentation / Q000379:methods; D012160:Retina / Q000033:anatomy & histology*; D014741:Video Recording