To determine the effect of sustained-release fluocinolone acetonide (0,2 µg/day FAc) intravitreal implant in the superficial capillary complex, imaged by optical coherence tomography angiography (OCTA) in patients with diabetic macular edema (DME), using the fractal dimension analysis.


A prospective analysis was performed in one eye with a chronic refractory DME treated with FAc intravitreal implant. OCTA images were acquired using the Spectralis HRA+OCT, Heidelberg Engineering. Automated segmentation was obtained through the superficial capillary complex, at the ganglion cell layer. Grayscale OCTA images were standardized and binarized using ImageJ. Fractal box-counting analyses were performed using Fractalyse. Fractal dimensions (FD) analyses of the superficial capillary complex were analysed at baseline, at month 1 and quarterly thereafter until the month 9 post-FAc implant treatment.


Observing the OCTA images is evident a densification of the vascular pattern, particularly when comparing the OCTA at month 1 (with less central macular edema, for a more reliable OCTA analysis) and the OCTA at the last follow-up visit. Corroborating this findings, the FD value at the end of follow-up was 1.734, greater when compared with the FD value at month 1 (1.727). The correlation coefficient was 0.999 in both time points.


Fractal dimension based on OCTA has the potential to quantitatively characterize retinal microvascular changes. Although diabetic retinopathy is associated with a FD reduction in capillary plexus, the use of a sustained-release FAc intravitreal implant suggests improvement of the vascularization pattern at the superficial capillary complex in chronic refractory DME. More comprehensive studies on larger subject populations and longitudinal studies are needed to confirm our preliminary results.



Bernardete PESSOA, Joao Coelho, Melo Beirao, Angelina Meireles
Centro Hospitalar do Porto – Hospital Santo Antonio
Email : bbtpessoa@gmail.com
Cell Phone: +351938469884
Work Phone: +351938469884