Imaging retinal inflammatory biomarkers after intravitreal steroid and anti-VEGF treatment in diabetic macular oedema

PurposeTo evaluate changes of specific retinal imaging biomarkers [intraretinal hyper-reflective retinal spots: HRS ; subfoveal neuroretinal detachment: SND; and increased foveal autofluorescence: IFAF after intravitreal steroid or anti-vascular endothelial growth factor treatment in diabetic macular oedema (DME)] as possible indicators of retinal inflammatory condition. MethodsRetrospective analysis of images and clinical charts of 49 eyes (49 patients) with DME treated with intravitreal dexamethasone (dexamethasone, 23 eyes) or intravitreal ranibizumab (ranibizumab, 26 eyes). All patients had fundus colour photograph, spectral domain optical coherence tomography (SD OCT) and fundus autofluorescence (FAF), best-corrected visual acuity (BCVA) and microperimetry recorded before and 1month after the end of treatment. Central macular thickness (CMT), number of HRS and presence of SND were evaluated by SD OCT. Fundus autofluorescence images were evaluated for area of (IFAF). Retinal sensitivity within 4 degrees and 12 degrees from fovea was quantified by microperimetry. Changes in morphologic and functional parameters were assessed, and correlation was performed by Pearson's correlation. ResultsBest-corrected visual acuity and CMT improved in all patients, (p<0.05, for both groups). Mean number of HRS decreased after both treatments (p<0.0001). Subfoveal neuroretinal detachment resolved in 85.7% dexamethasone-treated eyes (p=0.014) and in 50% ranibizumab-treated eyes (p=0.025). Mean IFAF area decreased in both groups, (p<0.0001, for both). A significantly higher decrease in CMT was observed in dexamethasone- versus ranibizumab-treated eyes, (p=0.032). In dexamethasone group, higher number of HRS at baseline and larger IFAF were correlated with higher increase in retinal sensitivity; eyes with SND at baseline had major decrease in CMT versus those without SND, (p=0.003). ConclusionHigher number of HRS, larger area of IFAF and presence of SND may indicate a prevalent inflammatory condition in DME with specific response to targeted treatment.