The relationship between fundus fluorescein angiographic findings and serous macular detachment in diabetic macular edema

Ultrastructural imaging biomarkers in diabetic macular edema: A major review

Diabetic macular edema (DME) is a vision-threatening complication of diabetic retinopathy and causes significant morbidity in patients. Anti-vascular endothelial growth factor (VEGF) agents are the mainstay of treatment for DME, with steroid implants being used for the treatment of anti-VEGF resistant eyes. Over the years, several classification systems have been devised to describe the patterns of DME using optical coherence tomography (OCT). With the advent of effective treatments, it has become imperative that imaging cues are not merely used for classifying the disease but also as biomarkers for prognostication of disease activity and treatment response. In this aspect, newer imaging findings such as hyperreflective dots, photoreceptor integrity, and disorganization of retinal inner layers have been characterized in detail by several authors. Macular perfusion analysis using OCT angiography is the latest in the armamentarium for imaging DME. In this narrative review, we have summarized all relevant literature related to the ultrastructural imaging-based biomarkers of DME and their correlation to treatment.

Diabetic macular edema with pachychoroid features

Background

To investigate the clinical features of diabetic macular edema (DME) in eyes with pachychoroid phenotypes using multimodal retinal imaging.

Methods

We retrospectively reviewed 210 eyes from 210 DME patients and analyzed the clinical and imaging parameters, including visual acuity, central macular thickness (CMT), subfoveal choroidal thickness (SFCT) and neural retina layer thickness (NRT). The DME eyes were divided into two groups: group 1 (80 eyes with submacular detachment [SMD]) and group 2 (130 eyes without SMD). The clinical and imaging parameters of 285 eyes from 285 diabetic patients without DME were collected as a control group.

Results

DME eyes with pachychoroid phenotypes were more frequent in group 1 than in group 2 (53 eyes [66.25%] and 53 eyes [40.77%], respectively, P < 0.001). Pachychoroid phenotypes were identified in 108 (37.90%) of the control eyes. CMT and NRT were greater in group 1 than in group 2. In group 1, 37 eyes had SMD combined with focal edema, and 43 eyes had SMD combined with diffuse-type edema. No significant difference in pachychoroid phenotypes was found between the focal and diffuse types (26 [70.27%] and 27 [62.79%], respectively, P = 0.481). In group 2, 70 eyes had focal-type edema, and 60 eyes had diffuse-type edema. No significant difference in the frequency of pachychoroid phenotypes was found (32 [45.71%] and 21 [35.00%], respectively, P = 0.215). Interestingly, among the 70 eyes with focal edema in group 2, 13 (40.6%) and 5 (13.2%) eyes with and without pachychoroid phenotypes showed no definite microaneurysms, respectively.

Conclusion

SMD and focal edema without definite microaneurysms may be clinical manifestations of DME with pachychoroid phenotypes and possibly related to choroidal circulation disturbance in DME.

Influence of serous retinal detachment on the outcome of ranibizumab treatment in diabetic macular oedema

PURPOSE

The purpose of this study was to evaluate the influence of serous retinal detachment (SRD) on the outcome of intravitreal ranibizumab (IVR) therapy in diabetic macular oedema (DME).

MATERIALS AND METHODS

Fifty-one eyes with cystoid macular oedema (CME) and SRD (study group) and 57 eyes with only CME (control group) that received pro re nata (PRN) IVR injections during a 6-month period were retrospectively evaluated. The outcome measures included changes in the central macular thickness (CMT) and best corrected visual acuity (BCVA) and injection numbers.

RESULTS

The mean initial CMT in the study and control groups was 467 ± 101 and 440 ± 89 µm, respectively. The mean BCVA in the study and control groups was 0.75 ± 0.38 and 0.59 ± 0.36 logarithm of minimal angle of resolution (LogMAR), respectively (p = 0.010). The study group received a mean of 2.2 ± 0.92 injections, whereas the control group received a mean of 2.54 ± 0.9 injections. The decrease in CMT was greater, but not significantly greater, in the study group than in the control group.

CONCLUSION

The presence of SRD resulted in a less favourable visual acuity (VA) outcome with IVR. Disruption of the ellipsoid zone and abnormality of the foveal avascular zone at the baseline examination were correlated with a lower VA. Both of the pathologies occurred more frequently in the SRD group.

Diabetic Macular Edema Pathophysiology: Vasogenic versus Inflammatory

Diabetic macular edema (DME) can cause blindness in diabetic patients suffering from diabetic retinopathy (DR). DM parameters controls (glycemia, arterial tension, and lipids) are the gold standard for preventing DR and DME. Although the vascular endothelial growth factor (VEGF) is known to play a role in the development of DME, the pathological processes leading to the onset of this disease are highly complex and the exact sequence in which they occur is still not completely understood. Angiogenesis and inflammation have been shown to be involved in the pathogenesis of this disease. However, it still remains to be clarified whether angiogenesis following VEGF overexpression is a cause or a consequence of inflammation. This paper provides a review of the data currently available, focusing on VEGF, angiogenesis, and inflammation. Our analysis suggests that angiogenesis and inflammation act interdependently during the development of DME. Knowledge of DME etiology seems to be important in treatments with anti-VEGF or anti-inflammatory drugs. Current diagnostic techniques do not permit us to differentiate between both etiologies. In the future, diagnosing the physiopathology of each patient with DME will help us to select the most effective drug.

Correlation of morphological pattern of optical coherence tomography in diabetic macular edema with systemic risk factors in middle aged males

To study correlation of different optical coherence tomography (OCT) patterns of diabetic macular edema (DME) with systemic risk factors. Institutional cross-sectional double-masked non-interventional study with 330 eyes of middle-aged male type 2 diabetes patients with DME. Various systemic parameters were measured. Diffuse retinal thickening (DRT), cystoid and serous patterns of DME were identified on OCT. Comparison between DRT versus non-DRT and serous versus non-serous eyes was done in respect to systemic parameters. Correlation of serous and DRT pattern was tested with systemic parameters above and below specified values. Mean age was 54.4 ± 7.1 years. Mean duration of diabetes was 8.7 ± 4.2 years. Mean serum globulin level was significantly higher (p = 0.018) in serous compared to non-serous group. Prevalence of serous DME was significantly high in those with serum globulin level >3.5 gm/dl (prevalence ratio = 3.01, p = 0.040). Significant correlation of central macular thickness was observed with duration of diabetes (p = 0.002, r = 0.440).Visual acuity (logMAR) was correlated significantly with HbA1C (p = 0.031, r = 0.305). Increased serum globulin, a positive phase reactant of inflammation, was found significant independent risk factor for development of serous DME. This study did not identify any modifiable systemic factor for any of the OCT patterns in DME.