Ischemic index changes in diabetic retinopathy after intravitreal dexamethasone implant using ultra-widefield fluorescein angiography: a pilot study

Aims: To investigate the effect of dexamethasone intravitreal implant on peripheral ischemia in patients affected by diabetic macular edema (DME). Methods: Patients with treatment-naïve diabetic retinopathy (DR) undergoing intravitreal dexamethasone implant for DME between October 2015 and March 2017 were enrolled. Patients underwent a comprehensive ocular examination at baseline (<2 weeks before treatment) and 10 ± 2 weeks after dexamethasone implant including best-corrected visual acuity (BCVA), intraocular pressure, optical coherence tomography, ultra-widefield (UWF) retinography and UWF fluorescein angiography (UWFA). Results: Nine eyes of seven consecutive patients (five males; mean age 66.4 ± 6.7 years) were enrolled. Mean duration of DR was 12.3 ± 8.4 years. Mean interval between UWFA acquisitions was 12.1 ± 2.1 weeks, and the mean interval between intravitreal injection and UWFA acquisition was 11.0 ± 1.6 weeks. Mean pre- and post-injection BCVA was 0.30 ± 0.20 and 0.21 ± 0.14 logMAR (p = 0.06), respectively. Mean pre- and post-injection central macular thickness was 449.8 ± 92.5 and 356.3 ± 52.4 μm (p = 0.03), respectively. Mean pre- and post-injection ischemic index was 24.0 ± 25.0 and 9.8 ± 12.1% (p = 0.0427), respectively. Conclusions: Intravitreal dexamethasone implant reduces peripheral retina ischemia in patients with DR.