Fundus Autofluorescence (488 Nm) and Near-Infrared Autofluorescence (787 Nm) Visualize Different Retinal Pigment Epithelium Alterations in Patients With Age-Related Macular Degeneration

Abstract

Patterns of FAF and NIA indicate different involvement of lipofuscin and melanin in the pathophysiological process and provide further insight into the development of AMD and noninvasive monitoring of future therapeutic interventions.

Noninvasive near infrared autofluorescence imaging of retinal pigment epithelial cells in the human retina using adaptive optics

“…Infrared autofluorescence (IRAF) is an increasingly-utilized clinical modality for visualization and monitoring of the health of the retinal pigment epithelial (RPE) cells in a variety of different diseases that include age-related macular degeneration [1][2][3], central serous chorioretinopathy [4], retinitis pigmentosa [5], ABCA4-associated retinopathies [6], Best vitelliform macular dystrophy [7], and others. Its clinical value is derived from the fact that it provides a complementary picture of retinal lesions, which from a macroscopic perspective appears to be similar to those visualized using other modalities (most typically compared to short-wavelength autofluorescence) but at a finer scale is often slightly or entirely distinct from other modalities [1,3,[5][6][7].…”

Near-infrared fundus autofluorescence imaging in a case of photic maculopathy

“…BAF derives mainly from lipofuscin, which is localized in the basal portion of the RPE cells, while IRAF visualizes selectively the melanin granules in RPE cells, which are normally localized in the apical portion of RPE cells [2] .Also, the pattern of blue and infrared autofluorescence of the normal macula is different: the center of the fovea, in fact, is normally hypo-autofluorescent in BAF, while IRAF has the maximal intensity at the center of the fovea and decrease eccentrically [2] . The physiological central BAF hypo-autofluorescence does not correspond to a reduced amount of lipofuscin in the center of the macula, but depends on the higher absorption of blue light (excitation light) by the yellow macular pigment [2] . BAF showed a reduced ability to detect the RPE changes visualized on OCT scans in the present case.…”

“…Blue and near-infrared fundus autofluorescence visualize different structures of the retina [2] . BAF derives mainly from lipofuscin, which is localized in the basal portion of the RPE cells, while IRAF visualizes selectively the melanin granules in RPE cells, which are normally localized in the apical portion of RPE cells [2] .Also, the pattern of blue and infrared autofluorescence of the normal macula is different: the center of the fovea, in fact, is normally hypo-autofluorescent in BAF, while IRAF has the maximal intensity at the center of the fovea and decrease eccentrically [2] .…”

“…Retinal pictures were obtained by SLO using three different imaging modalities: infrared (IR, 820nm), blue-autofluorescence (BAF, obtained with excitation at 488nm and a filter at 500nm), and near-infrared-autofluorescence imaging (IRAF, obtained with excitation at 790nm and a filter at 810nm) [2] . Figure 1 shows the clinical and instrumental findings at the baseline and during the follow-up of the patient.…”

Imaging of retinal and choroidal vascular tumours

“…This investigation amplifies and averages multiple sequential images, obtained with modern cSLO machines. 12 Two different methods of autofluorescence imaging exist: 23 Fundus autofluorescence is recorded with the 488 nm excitation and 4500 nm emission wavelength settings. The main fluorophore is lipofuscin, which is the end-product of phagocytosed photoreceptor outer segments, mostly accumulating within RPE cells.…”