Factors associated with the duration of action of dexamethasone intravitreal implants in diabetic macular edema patients

Hyperreflective Dots on OCT as a Predictor of Treatment Outcome in Diabetic Macular Edema: A Systematic Review

TOPIC

This review aims to evaluate the role of hyperreflective dots (HRDs), detected using OCT, as a predictor of the treatment outcome in patients with diabetic macular edema (DME).

CLINICAL RELEVANCE

The treatment of DME is possible, but its results are often unsatisfactory. Thus, it is important to develop biomarkers that can help to predict the treatment response to optimize the treatment's effect for individual patients.

METHODS

PubMed, Embase, Web of science, and Cochrane library were searched (final search date on May 5, 2021). Participants were patients diagnosed with DME and provided with treatment. The predictor was HRDs, detected using OCT, before treatment. The outcomes were best-corrected visual acuity (BCVA) and central macular thickness (CMT), detected using OCT, after treatment. Two reviewers independently screened the titles and abstracts as well as full text. The refined Quality in Prognosis Studies tool was used to assess the risk of bias for each included study. Because of the clinical heterogeneity of the studies, a meta-analysis was not performed.

RESULTS

Thirty-six studies were included. The Quality in Prognosis Studies assessment showed that most studies had a low or moderate risk of bias in 6 domains. Six studies could not find any correlation between baseline HRDs (either the presence or absence of HRDs [n = 1] or baseline HRD number [n = 5]) and outcome (BCVA or CMT), whereas 12 studies found a significant correlation between these variables. Eight studies reported that baseline HRDs could predict a poor visual outcome (n = 4 on prescence or abscence of HRD and n = 4 on HRD number), and 4 studies (n = 1 on prescence or abscence of HRD and n = 3 on HRD number) found that HRDs were predictive of visual improvement. Fifteen out of 17 studies found that the HRD number decreased after treatment.

CONCLUSION

Based on the current literature, the HRD numbers decrease with treatment, but it is not clear whether HRDs predict the treatment outcome in patients with DME. Future investigations with more uniform approaches are needed to confirm the nature of this biomarker and its effect on DME treatment outcome.

Significance of Hyperreflective Foci as an Optical Coherence Tomography Biomarker in Retinal Diseases: Characterization and Clinical Implications

Hyperreflective foci (HRF) is a term coined to depict hyperreflective dots or roundish lesions within retinal layers visualized through optical coherence tomography (OCT). Histopathological correlates of HRF are not univocal, spacing from migrating retinal pigment epithelium cells, lipid-laden macrophages, microglial cells, and extravasated proteinaceous or lipid material. Despite this, HRF can be considered OCT biomarkers for disease progression, treatment response, and prognosis in several retinal diseases, including diabetic macular edema, age-related macular degeneration (AMD), retinal vascular occlusions, and inherited retinal dystrophies. The structural features and topographic location of HRF guide the interpretation of their significance in different pathological conditions. The presence of HRF less than 30 μm with reflectivity comparable to the retinal nerve fiber layer in the absence of posterior shadowing in diabetic macular edema indicates an inflammatory phenotype with a better response to steroidal treatment. In AMD, HRF overlying drusen are associated with the development of macular neovascularization, while parafoveal drusen and HRF predispose to macular atrophy. Thus, HRF can be considered a key biomarker in several common retinal diseases. Their recognition and critical interpretation via multimodal imaging are vital to support clinical strategies and management.

Behavior of hyperreflective spots noted on optical coherence tomography following intravitreal therapy in diabetic macular edema: A systematic review and meta-analysis

Purpose:

Hyperreflective spots (HRS) are considered as spectral domain optical coherence tomography biomarkers in predicting response to intravitreal therapy (IVT) in diabetic macular edema (DME). We aimed to determine if there was a quantitative reduction in HRS following IVT in DME, if the response to antivascular endothelial growth factor (anti-VEGF) drugs was different from steroids, and if HRS-response was associated with improvement in visual acuity (VA) or reduction in central macular thickness (CMT).

Methods:

PubMed/MEDLINE, Scopus, ProQuest, CINAHL, Wiley online, and Web of Science were searched (between January 1, 2011 and July 1, 2020). Publication bias and heterogeneity were assessed. Meta-analysis was done using the random-effects model.

Results:

Totally, 1168 eyes from 19 studies were eligible for inclusion. IVT was associated with a reduction in quantitative HRS (z = -6.3, P < 0.0001). Studies, however, showed heterogeneity (I² = 93.2%). There was no difference between anti-VEGF and steroid therapies (P = 0.23). The evidence on predicting VA and CMT outcomes were limited by the number of analyzable studies, owing to the wide variation in individual study designs, and lack of randomized controlled trials.

Conclusion:

We could conclude that there is a definite reduction in quantitative HRS following either form of IVT. We highlight the lacunae in the existing literature on HRS in DME and propose goals for future studies to harness the advantage of this promising biomarker.