Dexamethasone for unresponsive diabetic macular oedema: optical coherence tomography biomarkers

Abstract

Purpose To analyse the effects of intravitreal dexamethasone implant (DEX) in patients with diabetic macular oedema (DME) unresponsive to ranibizumab treatment, in relation to the inflammatory optical coherence tomography (OCT) retinal features, subfoveal neuroretinal detachment (SND) and hyperreflective retinal spots (HRS). Methods Patients with DME poorly responsive to three injections of ranibizumab were treated with DEX. Best‐corrected visual acuity (BCVA) and central macula thickness (CMT, measured by Spectralis SD‐OCT) were assessed at baseline and at 1, 3, and 6 months. Results Overall, 44 eyes were included in the study. In the whole group, mean BCVA (baseline 51.5 ± 8.3 letters) increased significantly at 1 month (to 56.9 ± 8.8 letters; Tukey HSD p = 0.017) and was 55.5 ± 8.8 letters at 3 months (Tukey HSD p = 0.128). Central macula thickness (CMT) reduced significantly at 1 and 3 months (417 ± 149 μm and 469 ± 128 μm, respectively, both Tukey HSD p < 0.001 versus baseline). Subgroup analysis showed a significant BCVA increase at 1 month in eyes with SND + HRS (from 51.2 ± 9.2 to 58.2 ± 9.0, p = 0.029), and a trend to BCVA increase in eyes with HRS (from 52.3 ± 6.4 to 56.8 ± 7.9, p = 0.080), with a significant CMT decrease in both groups (p < 0.001). No changes of either parameter were found in eyes without SND and HRS. Conclusion Spectral domain OCT is useful in identifying some inflammatory features in DME. Among DME eyes ‘poorly responsive’ to ranibizumab, those with SND and HRS responded better to DEX implants than those without these features.

Subthreshold Micropulse Laser in Diabetic Macular Edema: 1-Year Improvement in OCT/OCT-Angiography Biomarkers

“… 29 These HRS have peculiar features, such as dimension <3 0 μm, reflectivity similar to that of the nerve fiber layer, absence of back-shadowing, and location in both the inner and outer retina. 29 Previous studies have demonstrated a decrease in the number of HRS after treatment with both intravitreal dexamethasone and anti-VEGF drugs 23 , 30 , 31 ; however, no evidence has been reported so far regarding the effect of SMPL on HRS during long-term follow-up. In this study, a progressive decrease in the number of HRS was documented up to 1 year after treatment with SMPL.…”

Effect of Dexamethasone Intravitreal Implant on Visual Acuity and Foveal Photoreceptor Integrity in Macular Edema Secondary to Retinal Vascular Disease

“…In patients with uveitic cystoid ME, DEX implant was able to reverse outer retinal layer alterations [29]. These findings were also observed in patients with ME associated with branch retinal vein occlusion (BRVO) [17, 30]. Moreover, it was suggested that DEX implant may recover morphology of outer retinal layer in patients with DME, which might be associated with better functional outcomes [13, 17, 31].…”

“…The relevance of these findings critically depends on whether early retina recovery will be associated with better functional outcomes. Since most of the evidence has evaluated the effect of DEX implant on ELM and EZ integrity in previously treated patients [13, 17, 28, 29, 31], it might be interesting to know what happens in treatment-naïve patients.…”

“…There is increasing evidence suggesting a significant relationship between the OCT appearance of the ELM or the EZ and the visual function in different RVD [12][13][14][15]. Different OCT biomarkers have been associated with functional outcomes in patients with age-related macular degeneration (AMD) [12,16]; diabetic macular edema (DME) [15,17]; retinal vein occlusion (RVO) [18]; and uveitis [19].…”

“…Understanding the natural history of a disease is fundamental to its management. Since chronic ME is associated with damaging of the ELM, photoreceptor segments, and disorganization of inner retinal layers [12][13][14][15][16][17][18][19][20], the treatment of ME should be performed as soon as possible in order to avoid structural retinal changes and irreversible damage of visual function [20].…”