June 2023
Volume 64, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2023
Is a decreased choriocapillaris perfusion implicated in the pathology of AMD? An OCTA – fundus autofluorescence study
Author Affiliations & Notes
  • Martin Hammer
    Ophthalmology, University Hospital Jena, Jena, Germany
    Center for Medical Optics and Photonics, Friedrich-Schiller-University Jena, Jena, Germany
  • Somar Hasan
    Ophthalmology, University Hospital Jena, Jena, Germany
  • Daniel Meller
    Ophthalmology, University Hospital Jena, Jena, Germany
  • Melih Tarhan
    Ophthalmology, University Hospital Jena, Jena, Germany
  • Footnotes
    Commercial Relationships   Martin Hammer None; Somar Hasan None; Daniel Meller None; Melih Tarhan None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science June 2023, Vol.64, 289. doi:
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    • Get Citation

      Martin Hammer, Somar Hasan, Daniel Meller, Melih Tarhan; Is a decreased choriocapillaris perfusion implicated in the pathology of AMD? An OCTA – fundus autofluorescence study. Invest. Ophthalmol. Vis. Sci. 2023;64(8):289.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Fundus autofluorescence (FAF) is widely used in AMD diagnostics. Fluorescence lifetime imaging ophthalmoscopy (FLIO) can characterize FAF by fluorescence lifetimes (tm) presumed to represent individual fluorophores as well as peak emission wavelength (PEW). Long tm and short PEW are known to be associated with AMD. Histology suggests an impaired choriocapillaris (cc) perfusion to be associated with AMD. Here we investigate whether tm or PEW are associated with the cc flow signal deficit (FD) in AMD patients.

Methods : Twenty-two patients (age 76±7.6 years) with intermediate, non-neovascular AMD were included. FAF tm were determined in a short- (SSC: 500–560 nm) and a long-wavelength (LSC: 560–720 nm) spectral channel of FLIO. The PEW was determined from the FAF intensity ratio in these channels. OCTA was recorded by Cirrus 5000 (Zeiss). The cc was segmented at a depth of 21 to 41 µm below the retinal pigment epithelium (RPE). The en-face OCTA image of the cc slab was multiplied by the invers reflectance image of this slab from OCT in order to compensate for signal reduction due to structures anterior to the cc (e.g. retinal vessels, RPE abnormalities, drusen). This compensated cc OCTA image was binarized using a local (radius 20 µm) threshold according to Phansalkar and the fraction of pixels, indicating non-perfusion, was calculated as FD. PEW, tm, and FD were averaged over the central area, the inner, and the outer ring of the ETDRS grid and Pearson correlation coefficients were determined between the parameters.

Results : Mean values and standard deviation of cc FD, tm, and PEW are given in table 1. No correlations were found between the tm and FD values. PEW in the outer ring correlated with FD in grid all areas (p=0.016, 0.033, and 0.026, respectively).

Conclusions : AMD is known to be associated with long tm and short PEW and over time tm lengthen significantly in AMD patients. Therefore, an implication of cc flow deficits in AMD pathology would suggest a positive correlation of tm and a negative one of PEW with FD. As only PEW in the outer ring was significantly correlated with FD, the involvement of cc perfusion deficits in AMD pathology seems questionable. However, FD showed a wide variability over the patients, and artefacts in the layer segmentation and in the measurement are possible.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Table 1: mean ± standard deviation of vessel density (FD), lifetimes tm, and PEW

Table 1: mean ± standard deviation of vessel density (FD), lifetimes tm, and PEW

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