Performance of Long-wavelength Autofluorescence Imaging

Overview

Fundus autofluorescence imaging has become an important diagnostic tool in ophthalmology, guiding diagnosis and assessment of progression of retinal diseases. This study investigates the performance of optimized long-wavelength autofluorescence imaging. To achieve this goal, the investigators will determine an optimal long wavelength excitation light and investigate the autofluorescence signal intensity in normals and patients with different retinal diseases. The diagnostic performance of the long-wavelength autofluorescence will be evaluated by assessing sensitivity and specificity for diagnosing a variety of degenerative retinal diseases and by comparing it to conventional autofluorescence.

Fundus autofluorescence (AF) imaging of the retina with confocal scanning laser ophthalmoscopy has been established as a non-invasive imaging modality for the diagnosis of retinal and macular diseases. Long-wavelength near-infrared autofluorescence (excitation: 787 nm, LW-AF) is a new, innovative alternative to the classic autofluorescence imaging using 488 nm blue excitation light. Excitation of the fluorophores at the ocular fundus using a longer wavelength has several advantages. However, with the current imaging technique the autofluorescence signal and thus image quality is considerably lower compared to conventional short-wavelength autofluorescence (SW-AF). This may be the main reason for the currently limited application and scarce scientific publications on this technique. Therefore, the objective of this study is to assess the performance of an optimized setup of long-wavelength autofluorescence imaging in clinical routine applications. For this purpose, additional laser sources will be integrated into a scanning laser ophthalmoscope and the performance with regards to image quality will be investigated systematically using different excitation wavelengths and filter combinations in healthy controls. In a next step, the signal intensity will be quantified using an integrated fluorescent reference. First, factors affecting measurements will be identified, followed by generation of a normative database. Subjects with various retinal diseases will then be investigated and compared to the normative database. Finally, the diagnostic performance of long-wavelength autofluorescence imaging to detect retinal degenerative diseases will be investigated and compared to conventional imaging techniques.