Mean macular intercapillary area in eyes with diabetic macular oedema after anti-vascular endothelial growth factor therapy and its association with treatment response

Two different initial treatment regimens of Conbercept in diabetic macular edema: 12-month results from a multicenter randomized controlled study

BACKGROUND

The optimal treatment regimen for diabetic macular edema (DME) and predictors for its treatment`s outcome need emerging evidence but currently poorly studied.

METHODS

A prospective, multicenter, open label randomized controlled study among adult patients with DME was conducted. Eyes were randomized to three or six doses initial Conbercept treatments. Additional injections were suggested pro re nata (PRN) over 12 months. Optical coherence tomography angiography (OCTA) was adopted to quantify the macular vessel density. Visual acuity gain and anatomical improvement and their associated factors were evaluated by multivariable linear regression.

RESULTS

41 patients with 59 eyes participated in current study. Patients in both 3 + PRN (n = 32 eyes) or 6 + PRN (n = 27 eyes) treatments experienced similar best-corrected visual acuity (BCVA) gain and anatomical improvement, including the central macular thickness, foveal avascular aone (FAZ) and the retinal vessel density. Over 12 months, eyes in the 6 + PRN group received better changes of the deep capillary plexus (2.53 ± 5.45%). In multivariate linear regression, the age significantly affected visual outcome in 3 + PRN group (β = -0.014, P = 0.028), while the initial CMT (β = -0.001, P = 0.022) and FAZ area (β = -0.946, P = 0.007) associated with visual outcome in 6 + PRN group. Furthermore, the duration of diabetes exhibited significant results on CMT among 3 + PRN group (β= -7.516, P = 0.04).

CONCLUSIONS

Both 3 + and 6 + initial treatment regimens of Conbercept loading dose achieved parallel anatomical and functional visual improvement, while 6 + group had a trend of better treatment outcome. Older age, higher initial CMT and longer duration of diabetes might influence the clinical outcomes over 12 months from baseline.

Persistent diabetic macular edema: Definition, incidence, biomarkers, and treatment methods

Intravitreal antivascular endothelial growth factor (anti-VEGF) treatment has drastically improved the visual and anatomical outcomes in patients with diabetic macular edema (DME); however, success is not always guaranteed, and a proportion of these eyes demonstrate persistent DME (pDME) despite intensive treatment. While standardized criteria to define these treatment-resistant eyes have not yet been established, many studies refer to eyes with no clinical response or an unsatisfactory partial response as having pDME. A patient is considered to have pDME if the retinal thickness improves less than 10-25% after 6 months of treatment. A range of treatment options have been recommended for eyes with pDME, including switching anti-VEGF agents, using corticosteroids and/or antioxidant drugs in adjunct with anti-VEGF therapy, and vitrectomy. In addition, multimodal imaging of DME eyes may be advantageous in predicting the responsiveness to treatment; this is beneficial when initiating alternative therapies. We explore the literature on persistent DME regarding its defining criteria, incidence, the baseline biological markers that may be useful in anticipating the response to treatment, and the available treatment options.

Microvascular Changes After Conbercept Intravitreal Injection of PDR With or Without Center-Involved Diabetic Macular Edema Analyzed by OCTA

Purpose

To investigate the intravitreal injection of conbercept as a treatment strategy for proliferative diabetic retinopathy (PDR) with or without center-involved diabetic macular edema (CI-DME) and evaluate its effect on the microvascular changes in the eyes.

Methods

In this prospective study, 43 patients including 29 cases (56 eyes) in CI-DME with PDR patients, and 14 cases (26 eyes) in the non-center involving diabetic macular edema (NCI-DME) with PDR patients were involved in this study. The best corrected visual acuity (BCVA), central retinal thickness (CRT), foveolar avascular zone (FAZ), and macular capillary vessel density (VD) of the superficial retinal capillary plexus (SCP) and deep retinal capillary plexus (DCP) were assessed before and after conbercept treatments for 1, 3, or 6 months.

Results

The BCVA was significantly increased after conbercept treatment in the eyes of CI-DME patients. After 6 months of treatment with the conbercept, microvascular density of the inferior area in SCP and the central fovea area in DCP increased significantly, regardless of the central fovea involvement. The effect of the conbercept treatment on the VD of NCI-DME was higher than that of CI-DME. Then, after 6 months of treatment, the CRT of patients with CI-DME and NCI-DME were decreased significantly.

Conclusions

In this study, an intravitreal injection of conbercept significantly improved vision, alleviated macular edema in patients with DME. Conbercept treatment also altered the microvascular density in the retina.

OCT-Angiography Changes in Patients with Diabetic Macular Edema Treated with Intravitreal Dexamethasone Implant

Purpose

Methods

Results

Conclusions

Application of Improved U-Net Convolutional Neural Network for Automatic Quantification of the Foveal Avascular Zone in Diabetic Macular Ischemia

OBJECTIVES

The foveal avascular zone (FAZ) is a biomarker for quantifying diabetic macular ischemia (DMI), to automate the identification and quantification of the FAZ in DMI, using an improved U-Net convolutional neural network (CNN) and to establish a CNN model based on optical coherence tomography angiography (OCTA) images for the same purpose.

METHODS

The FAZ boundaries on the full-thickness retina of 6 × 6 mm en face OCTA images of DMI and normal eyes were manually marked. Seventy percent of OCTA images were used as the training set, and ten percent of these images were used as the validation set to train the improved U-Net CNN with two attention modules. Finally, twenty percent of the OCTA images were used as the test set to evaluate the accuracy of this model relative to that of the baseline U-Net model. This model was then applied to the public data set sFAZ to compare its effectiveness with existing models at identifying and quantifying the FAZ area.

RESULTS

This study included 110 OCTA images. The Dice score of the FAZ area predicted by the proposed method was 0.949, the Jaccard index was 0.912, and the area correlation coefficient was 0.996. The corresponding values for the baseline U-Net were 0.940, 0.898, and 0.995, respectively, and those based on the description data set sFAZ were 0.983, 0.968, and 0.950, respectively, which were better than those previously reported based on this data set.

CONCLUSIONS

The improved U-Net CNN was more accurate at automatically measuring the FAZ area on the OCTA images than the traditional CNN. The present model may measure the DMI index more accurately, thereby assisting in the diagnosis and prognosis of retinal vascular diseases such as diabetic retinopathy.

Optical Coherence Tomography Angiography Biomarkers Predict Anatomical Response to Bevacizumab in Diabetic Macular Edema

PURPOSE

To identify biomarkers that may predict an early anatomical response to the treatment of diabetic macular edema (DME) with intravitreal bevacizumab (IVB) by means of optical coherence tomography angiography (OCTA).

METHODS

This study is a retrospective study of treatment-naïve patients with DME who underwent 6 × 6 mm OCTA imaging of the macula at baseline and after three monthly IVB injections. Thirty-six eyes of 23 patients were included. Eyes that demonstrated evidence of an early anatomical response, consisting of a >10% decrease in central macular thickness (CMT) (n = 18), were compared with those eyes that failed to show such an improvement (n = 18).

RESULTS

At baseline, early-response eyes had worse starting best-corrected visual acuity (BCVA, LogMAR 0.84 ± 0.41 versus LogMAR 0.51 ± 0.15, p = 0.004) and a larger CMT (490 ± 135 µm versus 356 ± 33 µm, p = 0.001), but smaller foveal avascular zones (FAZ) (0.309 ± 0.098mm versus 0.413 ± 0.095 mm, p = 0.003) compared with eyes that proved refractory to three monthly injections of IVB. The vascular density (VD) in both the foveal superficial and deep capillary plexuses was significantly greater in eyes that showed an early-treatment response compared with eyes that were non-responders (24.86 ± 6.90% versus 19.98 ± 7.13%, p = 0.045 and 32.30 ± 4.88% versus 26.95 ± 7.25%, p = 0.028, respectively). Early-treatment response to IVB was predicted by starting CMT (r ²= 0.266, p = 0.001), FAZ size (r ²= 0.234, p = 0.003), and VD in the superficial parafovea (r ²= 0.217, p = 0.004) and deep fovea (r ²= 0.157, p = 0.037).

CONCLUSION

Projection-resolved OCTA may be useful in predicting an early anatomical response of DME to treatment with IVB.