Evaluation of thickness of individual macular retinal layers in diabetic eyes from optical coherence tomography.

The effect of diabetes mellitus (DM) on individual retinal layers remains incompletely understood. We evaluated the intra-retinal layer thickness alterations in 71 DM eyes with no diabetic retinopathy (DR), 90 with mild DR, and 63 with moderate DR without macular edema, using spectral-domain optical coherence tomography (SD-OCT) and the Iowa Reference Algorithm for automated retinal layer segmentation. The average thickness of 10 intra-retinal layers was then corrected for ocular magnification using axial length measurements, and pairwise comparisons were made using multivariable linear regression models adjusted for gender and race. In DM no DR eyes, significant thinning was evident in the ganglion cell layer (GCL; p < 0.001), inner nuclear layer (INL; p = 0.001), and retinal pigment epithelium (RPE; p = 0.014) compared to normal eyes. Additionally, mild DR eyes exhibited a thinner inner plexiform layer (IPL; p = 0.008) than DM no DR eyes. Conversely, moderate DR eyes displayed thickening in the INL, outer nuclear layer, IPL, and retinal nerve fiber layer (all p ≤ 0.002), with notably worse vision. These findings highlight distinctive patterns: early diabetic eyes experience thinning in specific retinal layers, while moderate DR eyes exhibit thickening of certain layers and slightly compromised visual acuity, despite the absence of macular edema. Understanding these structural changes is crucial for comprehending diabetic eye complications.

Optical coherence tomography choroidal enhancement using generative deep learning.

Spectral-domain optical coherence tomography (SDOCT) is the gold standard of imaging the eye in clinics. Penetration depth with such devices is, however, limited and visualization of the choroid, which is essential for diagnosing chorioretinal disease, remains limited. Whereas swept-source OCT (SSOCT) devices allow for visualization of the choroid these instruments are expensive and availability in praxis is limited. We present an artificial intelligence (AI)-based solution to enhance the visualization of the choroid in OCT scans and allow for quantitative measurements of choroidal metrics using generative deep learning (DL). Synthetically enhanced SDOCT B-scans with improved choroidal visibility were generated, leveraging matching images to learn deep anatomical features during the training. Using a single-center tertiary eye care institution cohort comprising a total of 362 SDOCT-SSOCT paired subjects, we trained our model with 150,784 images from 410 healthy, 192 glaucoma, and 133 diabetic retinopathy eyes. An independent external test dataset of 37,376 images from 146 eyes was deployed to assess the authenticity and quality of the synthetically enhanced SDOCT images. Experts' ability to differentiate real versus synthetic images was poor (47.5% accuracy). Measurements of choroidal thickness, area, volume, and vascularity index, from the reference SSOCT and synthetically enhanced SDOCT, showed high Pearson's correlations of 0.97 [95% CI: 0.96-0.98], 0.97 [0.95-0.98], 0.95 [0.92-0.98], and 0.87 [0.83-0.91], with intra-class correlation values of 0.99 [0.98-0.99], 0.98 [0.98-0.99], and 0.95 [0.96-0.98], 0.93 [0.91-0.95], respectively. Thus, our DL generative model successfully generated realistic enhanced SDOCT data that is indistinguishable from SSOCT images providing improved visualization of the choroid. This technology enabled accurate measurements of choroidal metrics previously limited by the imaging depth constraints of SDOCT. The findings open new possibilities for utilizing affordable SDOCT devices in studying the choroid in both healthy and pathological conditions.

Ocular microvascular complications in diabetic retinopathy: insights from machine learning.

INTRODUCTION: Diabetic retinopathy (DR) is a leading cause of preventable blindness among working-age adults, primarily driven by ocular microvascular complications from chronic hyperglycemia. Comprehending the complex relationship between microvascular changes in the eye and disease progression poses challenges, traditional methods assuming linear or logistical relationships may not adequately capture the intricate interactions between these changes and disease advances. Hence, the aim of this study was to evaluate the microvascular involvement of diabetes mellitus (DM) and non-proliferative DR with the implementation of non-parametric machine learning methods. RESEARCH DESIGN AND METHODS: We conducted a retrospective cohort study that included optical coherence tomography angiography (OCTA) images collected from a healthy group (196 eyes), a DM no DR group (120 eyes), a mild DR group (71 eyes), and a moderate DR group (66 eyes). We implemented a non-parametric machine learning method for four classification tasks that used parameters extracted from the OCTA images as predictors: DM no DR versus healthy, mild DR versus DM no DR, moderate DR versus mild DR, and any DR versus no DR. SHapley Additive exPlanations values were used to determine the importance of these parameters in the classification. RESULTS: We found large choriocapillaris flow deficits were the most important for healthy versus DM no DR, and became less important in eyes with mild or moderate DR. The superficial microvasculature was important for the healthy versus DM no DR and mild DR versus moderate DR tasks, but not for the DM no DR versus mild DR task-the stage when deep microvasculature plays an important role. Foveal avascular zone metric was in general less affected, but its involvement increased with worsening DR. CONCLUSIONS: The findings from this study provide valuable insights into the microvascular involvement of DM and DR, facilitating the development of early detection methods and intervention strategies.

Diabetic Macular Oedema Guidelines: An Australian Perspective.

The number of people living with diabetes is expected to rise to 578 million by 2030 and to 700 million by 2045, exacting a severe socioeconomic burden on healthcare systems around the globe. This is also reflected in the increasing numbers of people with ocular complications of diabetes (namely, diabetic macular oedema (DMO) and diabetic retinopathy (DR)). In one study examining the global prevalence of DR, 35% of people with diabetes had some form of DR, 7% had PDR, 7% had DMO, and 10% were affected by these vision-threatening stages. In many regions of the world (Australia included), DR is one of the top three leading causes of vision loss amongst working age adults (20-74 years). In the management of DMO, the landmark ETDRS study demonstrated that moderate visual loss, defined as doubling of the visual angle, can be reduced by 50% or more by focal/grid laser photocoagulation. However, over the last 20 years, antivascular endothelial growth factor (VEGF) and corticosteroid therapies have emerged as alternative options for the management of DMO and provided patients with choices that have higher chances of improving vision than laser alone. In Australia, since the 2008 NHMRC guidelines, there have been significant developments in both the treatment options and treatment schedules for DMO. This working group was therefore assembled to review and address the current management options available in Australia.

Dietary Intake and Diabetic Retinopathy: A Systematic Review of the Literature.

Diabetic retinopathy (DR) is a common microvascular complication of diabetes mellitus. The evidence connecting dietary intake and DR is emerging, but uncertain. We conducted a systematic review to comprehensively summarize the current understanding of the associations between dietary consumption, DR and diabetic macular edema (DME). We systematically searched PubMed, Embase, Medline, and the Cochrane Central Register of Controlled Trials between January 1967 to May 2022 for all studies investigating the effect of diet on DR and DME. Of the 4962 articles initially identified, 54 relevant articles were retained. Our review found that higher intakes of fruits, vegetables, dietary fibers, fish, a Mediterranean diet, oleic acid, and tea were found to have a protective effect against DR. Conversely, high intakes of diet soda, caloric intake, rice, and choline were associated with a higher risk of DR. No association was seen between vitamin C, riboflavin, vitamin D, and milk and DR. Only one study in our review assessed dietary intake and DME and found a risk of high sodium intake for DME progression. Therefore, the general recommendation for nutritional counseling to manage diabetes may be beneficial to prevent DR risk, but prospective studies in diverse diabetic populations are needed to confirm our findings and expand clinical guidelines for DR management.

One-year real-world outcomes of bevacizumab for the treatment of macular oedema secondary to retinal vein occlusion.

BACKGROUND: Bevacizumab is the only agent that many people can afford, yet there are only limited data on whether it improves macular oedema (MO) secondary to retinal vein occlusion (RVO) in real-world clinical practice. Here we studied 12-month real-world treatment outcomes of bevacizumab for RVO-related MO. METHODS: This was a multicentre, observational study analysing 12-month data from the Fight Retinal Blindness! (FRB) database. We studied treatment-naïve eyes with MO secondary to RVO commencing bevacizumab therapy between June 2009 and June 2019. Visual acuity (VA) and central subfield thickness (CST) were measured at baseline, 6 and 12 months. The primary outcome was a change in VA from baseline to 12 months. RESULTS: Two hundred and twenty treatment naive eyes were analyzed. The baseline VA for BRVO was better than CRVO (55.8 vs. 42.6 LogMAR letters) and this gap widened over the 12-month period, with a 12-month VA change of +14.0 (95% CI 11.1, 16.8) letters for BRVO and + 11.9 (95% CI 6.4, 17.4) for CRVO. The mean CST at baseline was 511 µm for BRVO and 627 µm for CRVO, falling at 12 months by -155 µm (-190, -121) in BRVO and -198 µm (-252, -145) in CRVO. The median number of injections for BRVO and CRVO completers was 7 (5, 9). CONCLUSIONS: Bevacizumab can be an effective treatment of RVO-MO in a real-world setting with outcomes approaching those reported by the seminal clinical trials. The functional and anatomical outcomes of intravitreal therapy were better for BRVO than CRVO.

Characterization of Poor Visual Outcomes of Diabetic Macular Edema: The Fight Retinal Blindness! Project.

PURPOSE: To investigate the incidence, characteristics, and baseline predictors of poor visual outcomes in eyes with diabetic macular edema (DME) receiving intravitreal therapy in routine clinical practice. DESIGN: Observational study. PARTICIPANTS: Treatment-naïve eyes starting intravitreal therapy for DME between 2014 and 2018 tracked in the Fight Retinal Blindness! registry. We examined 2 groups with poor visual outcomes: (1) those with sustained vision loss of > 10 letters from baseline without recovery of visual acuity (VA); and (2) those with a VA of < 55 letters at 2 years. Respective controls were eyes that did not experience poor visual outcomes. METHODS: Kaplan-Meier curves analyzed the proportion of eyes that experienced poor outcomes. Cox proportional hazards models evaluated the potential baseline predictors of poor outcomes. MAIN OUTCOME MEASURES: The proportion of eyes that experienced poor visual outcomes within 2 years of treatment initiation and its baseline predictors. RESULTS: The proportion of eyes with sustained VA of ≥ 10 letter loss was 14% at 2 years; 16% of eyes had VA of ≤ 55 letters 2 years after starting intravitreal therapy. Initial treatment with intravitreal corticosteroid was independently associated with a higher incidence of ≥ 10 letter loss (hazard ratio [HR], 3.21; 95% confidence interval [CI], 1.60-6.44; P < 0.01). No improvement in the VA at 3 months after starting treatment was associated with ≥ 10 letter loss (HR, 6.81; 95% CI, 4.11-11.27; P < 0.01) and VA of ≤ 55 letters at 2 years (HR, 4.28; 95% CI, 2.66-6.89; P < 0.01). The other factors related to higher risk of VA of ≤ 55 letters were older age (HR, 1.02 per year; 95% CI, 1-1.04; P = 0.04) and poor baseline VA (HR, 0.68 per 5 letters; 95% CI, 0.65-0.72, P < 0.001). CONCLUSIONS: Fourteen percent of eyes managed with intravitreal therapy in routine clinical care experienced ≥ 10 letter loss and 16% had VA of ≤55 letters 2 years after starting the treatment for DME. The identification of the incidence and predictors of poor outcomes provides a more accurate assessment of the potential benefit from intravitreal therapy.

Emerging corticosteroid delivery platforms for treatment of diabetic macular edema.

INTRODUCTION: Diabetic macular edema (DME) is a leading cause of vision impairment. Low-grade inflammation is thought to play a critical role in its pathogenesis. Although vascular endothelial growth factor inhibitors are used first-line, not all eyes with DME respond optimally and may respond better to corticosteroids. Currently corticosteroids for DME are given intravitreally and require regular monitoring. There is an unmet need for longer lasting therapies and/or effective noninvasive therapies such as those given via oral or topical routes. AREAS COVERED: This review discusses emerging corticosteroid delivery platforms for DME treatment. A literature search of investigational novel therapeutic steroid delivery platform in DME was conducted. Results are presented from preclinical, phase 1,2 & 3 clinical trials of various drug delivery systems using new technologies such as Solubilizing Nanoparticle technology, Mucus Penetrating Particles technology and Particle Replication In Non-wetting Templates. These new platforms aim to deliver corticosteroids effectively via topical, episcleral, subtenon, oral, and intravitreal routes. EXPERT OPINION: These novel drug delivery platforms have the potential to lead to noninvasive or minimally invasive therapies and may overcome the shortcomings of current pharmacotherapy. However, larger comparative trials are needed for these agents to be added to the current armamentarium in DME management.

Ocular Syphilis: An Update.

This review aims to provide an update on the clinical presentation, diagnosis, and treatment of ocular syphilis. While ocular syphilis is not a new phenomenon, recent resurgence in the incidence of overall syphilis, particularly among HIV-positive individuals, has sparked a new interest in an old disease. The challenge of ocular syphilis is manifold: firstly, it manifests in a spectrum of ways that can occur at any stage of the disease, with the most common finding being panuveitis. It may occur as early as 6 weeks after transmission and may be the only presenting feature of systemic syphilis; secondly, the relationship between HIV and syphilis has been established, as primary syphilis facilitates HIV transmission and HIV may modify the natural course of syphilis, increasing the propensity of the disease to progress to neurosyphilis. The authors present the latest updates to the changing landscape of ocular syphilis.