Abstract
Purpose :
To evaluate and compare two blue-light fundus autofluorescence (BAF) systems with 480 nm and 455 nm excitation source in patients with cataract undergoing surgery.
Methods :
In a pilot prospective study, 16 patients with different cataract grades based on LOCS classification (N1-3, C1-3) were assessed with two BAF systems, Spectralis-HRA (Heidelberg Engineering, Heidelberg, Germany) and Eidon-AF (Centervue SpA, Padova, Italy), before and one month after cataract surgery. Spectralis uses a 488 nm laser to excite retinal fluorophores, to assess autofluorescence (AF) and lipofuscin in a monochromatic mode. Eidon, is a blue LED system (440-475 nm, peak at 450 nm), which detects short (green) and long (red) wave AF emission components in chromatic images. Outcomes were evaluated by 2 independent readers as hypo-AF, hyper-AF, iso-AF and not-identifiable (NI), in a 5 ETRDS segment distribution. In addition, the Eidon chromatic BAF images were evaluated with the custom Color-Segmentation software, (Centervue, Italy) to quantify BAF emission wavelength components.
Results :
Before cataract surgery, 2 patients (N2C1 and N3C1) had NI scores in all ETDRS segments for both systems. All N2C2 patients (4), had score disagreements between systems in at least 2 ETDRS segments, while Eidon showed 8 NI scores, Spectralis showed 5 iso-AF and 3 hyper-AF. The other 10 patients had identical scores with both instruments. After cataract surgery all scores were the same for both Spectralis and Eidon. Although there were no statistically significant differences in scores between group means by two-way ANOVA F(1,128)=2.964, p=0.0875, a multiple t-test analysis showed significant score difference on cataract type N2C2 (p=0.0040) before surgery. No significance was found on any other cataract type. The Eidon chromatic BAF emission range before and after surgery did not change; however, the image signal intensity level to differentiate AF stages changed from <50 to <25 for hypo-AF, >120 to >125 for hyper-AF and a range of 75-140 to 50-185 for iso-AF.
Conclusions :
Lipofuscin emission after BAF, was more difficult to assess on Eidon than Spectralis in N2C2 cataracts, while there was not significant difference in other cataract grades. The Eidon chromatic BAF emission and signal intensity levels were different after surgery.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.