Abstract
Purpose :
The purpose of this study is to compare the fluorescence lifetime (FLT) of the fundus before and after the intravitreal ranibizumab injection for exudative age-related macular degeneration (AMD).
Methods :
Seventeen consecutive patients with exudative AMD were examined with fluorescence lifetime imaging ophthalmoscopy (FLIO: Heidelberg Engineering GmbH) before and 4 weeks after a scheduled intravitreal injection of ranibizumab. Number of past injection and the condition of the pre-treatment retina were not specified. The FLT was calculated for the separated macular areas defined by the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. The relationship between the change in visual acuity and the change in FLT (△τm) or central retinal thickness (△CRT) was assessed with an univariate regression analysis.
Results :
The △CRT after a single injection of ranibizumab ranged from -80 µm to 47 µm, with the median of 0 µm. The range of △τm at the center was -166 ps to 293 ps, with the median of 8 ps for the short spectral channel (SSC: 498-560 nm), and -116 ps to 60 ps, with the median of 0 ps for the long spectral channel (LSC: 560-720 nm). In the inner ring △τm ranged from -163 ps to 175 ps in SSC and from -68 to 28 ps in LSC, and in the outer ring from -126 ps to 9 ps in SSC and -49 ps to 26 ps in LSC. The results of the regression analysis showed that a decrease in FLT (negative △τm) is significantly associated with an increase in visual acuity (p<0.01) in all three analyzed areas in both channels. In contrast, there was no significant association between the change in visual acuity and the △CRT.
Conclusions :
The change in FLT induced by ranibizumab injection was shown to vary widely among individuals. However, it was shown that the shortening of FLT in the macula is associated with the improved visual acuity more strongly than the change in the morphology of the central retina. This presumably reflects activation of the metabolic state of the retinal cells. Therefore, using FLIO to evaluate the changes in FLT before and after anti-VEGF injection may be useful in evaluating the response of the metabolic state and function of the retina to anti-VEGF treatment.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.