Fundus autofluorescence imaging compared with different confocal scanning laser ophthalmoscopes

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Diagnostics

Background:

• Fundus autofluorescence (FAF) visualizes lipofuscin accumulation in the retinal pigment epithelium.
• Confocal scanning laser ophthalmoscopes (cSLO) are used for in vivo FAF imaging.
• Varied cSLO instruments exist for documenting FAF.

Purpose of the Study:

• To analyze and compare FAF imaging results from three different cSLO instruments.
• To evaluate the performance of Heidelberg Retina Angiograph (HRA), Rodenstock cSLO (RcSLO), and Zeiss Prototype (ZcSLO) for FAF.
• To assess differences in image quality, specifically grey scale values and contrast.

Main Methods:

• Eight healthy eyes and 18 diseased eyes (AMD, macular dystrophy, CSR) were examined.
• FAF images were acquired using HRA, RcSLO, and ZcSLO with an argon laser (488 nm).
• Images were aligned, averaged, and analyzed for grey scale values and RMS contrast.

Main Results:

• HRA and ZcSLO demonstrated significantly higher grey scale values and RMS contrast than RcSLO (p<0.0001).
• No significant difference in image quality was found between HRA and ZcSLO (p<0.05).
• RcSLO images appeared darker due to lower contrast and grey scale levels.

Conclusions:

• All tested cSLOs provide clinically useful FAF imaging for retinal diseases.
• HRA and ZcSLO offer superior image quality (brightness, contrast) over RcSLO.
• Standardization of photodetector gain and laser amplification is crucial for absolute FAF comparison across instruments.