First Author: M.Morkhat BELARUS
Co Author(s): T. Katulskaya N. Korolkova M. Shkudnova 0 0 0 0 0 0 0 0 0
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To assess the diagnostic value of fundus autofluorescence imaging (FAF) compared with ophthalmoscopy and spectral-domain optical coherence tomography (SD-OCT); and to investigate the correlation between the results of retinal visualisation obtained by these methods and visual acuity in patients with the exudative age-related macular degeneration (AMD) before and after anti–vascular endothelial growth factor (anti-VEGF) therapy, with determination of the best visual prognostic factors after treatment with intravitreal bevacizumab injection (IVB).
Ophthalmology Department, Vitebsk State Medical University, Vitebsk, Belarus
Eligibility criteria for this study included previously untreated exudative AMD with best-corrected visual acuity (BCVA) from 0.08 to 0.8. To eliminate the effect of concomitant ocular pathology on VA, patients who had glaucoma, high myopia (spherical equivalent more than -6 dioptres) were excluded. Eyes included in the study should also have good transparency of optical media. These entry criteria were also a prerequisite for high-quality imaging, which included FAF, SD-OCT and fundus photography performed for each eye included in the study. Fundus photography and FAF were obtained using a VISUCAM 500 fundus camera (Carl Zeiss) with excitatory (510-580nm) and barrier (650-735nm) filters for FAF. SD-OCT of the macular area was performed on SOCT Copernicus+ (OPTOPOL). For the research analysis the results of the above named visualisation methods obtained at baseline and two or three weeks after the third bevacizumab injection were used (ie 3-4 months after the start of intravitreal therapy). To determine the influence of the retinal pigment epithelium (RPE) changes on BCVA, we analysed the status of this retinal layer visualised independently by FAF, SD-OCT and ophthalmoscopy. Documented changes of the RPE were classified for each method as either significant (major) or insignificant (minor).
34 eyes from 34 patients were included in the study. The mean patient age was 69 years. BCVA before treatment was 0.2 (0.08 to 0.8). After IVB treatment BCVA significantly increased (p <0.001): 0.3 (0.1 to 1.0). The main FAF feature in the eyes with high BCVA before and after treatment was the area of mottling hyperautofluorescence in the macular region (p = 0.002), which corresponded to a flat neuroretinal detachment with a preserved continuous line of RPE on SD-OCT. Statistical analysis showed that SD-OCT compared to FAF and ophthalmoscopy less objectively reflected the status of the RPE layer and visual functions potential. Thus BCVA after treatment in eyes with minor RPE changes according to FAF was significantly higher (0.6 ± 0.21) than in eyes with significant changes 0.2 (0.1, 0.3) shown by FAF (p <0.001). Ophthalmoscopy RPE visualization results showed the same pattern. The same statistically significant differences in BCVA for eye groups with significant and insignificant RPE changes were observed for FAF and ophthalmoscopy before treatment. This trend, however, was not discernible for the SD-OCT method: significant difference in BCVA was not revealed before and after treatment between groups with significant and insignificant RPE changes according to SD-OCT.
RPE changes identified by FAF to a greater extent (p <0.001) than the data obtained by SD-OCT (p = 0.478) significantly correlate to BCVA in patients with wet AMD before and after anti-VEGF therapy. The advantage of the FAF over ophthalmoscopy or SD-OCT is that the RPE changes can be visualised and recorded earlier and with greater accuracy. SD-OCT mainly visualises optical thickness of the retina and the architecture of its layers, but provides less information than FAF about the integrity of the complex photoreceptors/RPE and thus the potential in terms of BCVA with the anti-VEGF treatment. Significant changes of the RPE layer (zones of hypoautofluorescence in the macular region surrounded by a hyperautofluorescence ring) on FAF were predictors of poor BCVA after the anti-VEGF treatment. The FAF method can be effectively used in clinical practice to assess the functional status of the macular area in patients with exudative AMD, and to determine visual prognostic factors (functional outcomes) after anti-VEGF therapy in the case of treatment response with a good anatomical outcome (resolution or significant decrease of exudation).