Comparison of fundus autofluorescence images acquired by the confocal scanning laser ophthalmoscope (488 nm excitation) and the modified Topcon fundus camera (580 nm excitation)

Abstract

To compare autofluorescence (AF) images obtained with the confocal scanning laser ophthalmoscope (using the Heidelberg retina angiograph; HRA) and the modified Topcon fundus camera, in a routine clinical setting. A prospective comparative study conducted at the Jules-Gonin Eye Hospital. Fifty-six patients from the medical retina clinic. All patients had complete ophthalmic slit-lamp and fundus examinations, colour and red-free fundus photography, AF imaging with both instruments, and fluorescein angiography. Cataract and fixation were graded clinically. AF patterns were analyzed for healthy and pathological features. Differences of image noise were analyzed by cataract grading and fixation. A total of 105 eyes were included. AF patterns discovered by the retina angiograph and the fundus camera images, respectively, were a dark optic disc in 72 % versus 15 %, a dark fovea in 92 % versus 4 %, sub- and intraretinal fluid visible as hyperautofluorescence on HRA images only, lipid exudates visible as hypoautofluorescence on HRA images only. The same autofluorescent pattern was found on both images for geographic atrophy, retinal pigment changes, drusen and haemorrhage. Image noise was significantly associated with the degree of cataract and/or poor fixation, favouring the fundus camera. Images acquired by the fundus camera before and after fluorescein angiography were identical. Fundus AF images differ according to the technical differences of the instruments used. Knowledge of these differences is important not only for correctly interpreting images, but also for selecting the most appropriate instrument for the clinical situation.

Clinical applications of fundus autofluorescence in retinal disease

“…Fundus cameras also provide better detection of exudative retinal disease such as choroidal neovascularization or central serous chorioretinopathy compared to cSLOs [54]. However, even with modification, fundus cameras capture more reflected and scattered light compared to confocal systems [53, 55]. Scattered light from structures outside the retinal plane may falsely increase the FAF signal, a phenomena termed pseudo-autofluorescence [54].…”

“…Because the excitation spectra of fundus cameras differs from that of fluorescein angiography, the two imaging modalities can be used in any order without interference [55]. Additional advantages of fundus cameras include color imaging capability and greater resistance to motion artifact in cases of poor fixation.…”

Enface vitreous OCT ‘worm holes’: A novel finding in a patient with diffuse unilateral subacute neuroretinitis (DUSN)

“…2 B). 11 However, this hypothesis is entirely speculative and would require further clinical and basic research to elucidate the basis of nematode motility.…”

Fundus autofluorescence and multicolour imaging comparison in assessing disease severity in patients suffering from geographic atrophy. A case series analysis

“…There are several studies that compare FAF to fundus cameras [23][24][25][26], confocal scanning laser ophthalmoscope [23][24][25] (cSLO), and spectral--domain optical coherence tomography [27,28] (sd-OCT) as well as studies comparing multicolour imaging to fundus photography [29], but to our knowledge there has been no study comparing FAF to multicolour imaging.…”