The potential of spectral domain optical coherence tomography imaging based retinal biomarkers

Deep-Learning-Based Group Pointwise Spatial Mapping of Structure to Function in Glaucoma

Purpose

To establish generalizable pointwise spatial relationship between structure and function through occlusion analysis of a deep-learning (DL) model for predicting the visual field (VF) sensitivities from 3-dimensional (3D) OCT scan.

Design

Retrospective cross-sectional study.

Participants

A total of 2151 eyes from 1129 patients.

Methods

A DL model was trained to predict 52 VF sensitivities of 24-2 standard automated perimetry from 3D spectral-domain OCT images of the optic nerve head (ONH) with 12 915 OCT-VF pairs. Using occlusion analysis, the contribution of each individual cube covering a 240 × 240 × 31.25 μm region of the ONH to the model's prediction was systematically evaluated for each OCT-VF pair in a separate test set that consisted of 996 OCT-VF pairs. After simple translation (shifting in x- and y-axes to match the ONH center), group t-statistic maps were derived to visualize statistically significant ONH regions for each VF test point within a group. This analysis allowed for understanding the importance of each super voxel (240 × 240 × 31.25 μm covering the entire 4.32 × 4.32 × 1.125 mm ONH cube) in predicting VF test points for specific patient groups.

Main Outcome Measures

The region at the ONH corresponding to each VF test point and the effect of the former on the latter.

Results

The test set was divided to 2 groups, the healthy-to-early-glaucoma group (792 OCT-VF pairs, VF mean deviation [MD]: -1.32 ± 1.90 decibels [dB]) and the moderate-to-advanced-glaucoma group (204 OCT-VF pairs, VF MD: -17.93 ± 7.68 dB). Two-dimensional group t-statistic maps (x, y projection) were generated for both groups, assigning related ONH regions to visual field test points. The identified influential structural locations for VF sensitivity prediction at each test point aligned well with existing knowledge and understanding of structure-function spatial relationships.

Conclusions

This study successfully visualized the global trend of point-by-point spatial relationships between OCT-based structure and VF-based function without the need for prior knowledge or segmentation of OCTs. The revealed spatial correlations were consistent with previously published mappings. This presents possibilities of learning from trained machine learning models without applying any prior knowledge, potentially robust, and free from bias.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Five-year changes in macular thickness in the elderly population: A cohort study

BACKGROUND

The aim of this study is to determine the 5-year changes in macular thickness and related factors.

METHODS

Data were from the second (2014) and third (2019) phases of the Shahroud Eye Cohort Study. Examinations included measurement of uncorrected and best-corrected visual acuity, non-cycloplegic autorefraction, slit-lamp biomicroscopy, and funduscopy. Participants underwent Cirrus HD-OCT 4000 (Carl Zeiss Meditec, Dublin, CA).

IMAGING

RESULTS

The 5-year changes (95% confidence interval) of central and overall macular thicknesses were - 3.48 ± 8.16 μ (-3.92, -3.03) and - 0.79 ± 4.06 μ (-1.03, -0.54), respectively. The median and IQR of 5-year changes in the central subfield thickness were -3 and 10, although they were 0 and 5 in the overall macular thickness, respectively. Multiple regression model showed the central macular thickness (CMT) decreased with a U-shape pattern with increasing age. The 5-year changes in CMT were significantly lower in females compared to males β = -1.55; (-2.78, -0.32) and in smokers compared to non-smokers β = -1.92; (-3.55, -0.28). Moreover, higher body mass index β = -0.12; (-0.22, -0.02) and CMT at baseline β = -0.08; (-0.10, -0.06) were significantly associated with lower CMT changes. The average 5-year changes in overall macular thickness showed a non-linear decrease with age and was significantly higher in females β = 0.93; (0.4, 1.43). These changes were directly related to the anterior chamber depth β = 0.87; (0.10, 1.64) in the baseline.

CONCLUSIONS

The macular thickness decreased slightly after 5 years; however, this change is not clinically significant. Demographic factors such as age and sex and refractive errors were significantly related to macular thickness changes.

Deep Learning in Neovascular Age-Related Macular Degeneration

Background and objectives: Age-related macular degeneration (AMD) is a complex and multifactorial condition that can lead to permanent vision loss once it progresses to the neovascular exudative stage. This review aims to summarize the use of deep learning in neovascular AMD. Materials and Methods: Pubmed search. Results: Deep learning has demonstrated effectiveness in analyzing structural OCT images in patients with neovascular AMD. This review outlines the role of deep learning in identifying and measuring biomarkers linked to an elevated risk of transitioning to the neovascular form of AMD. Additionally, deep learning techniques can quantify critical OCT features associated with neovascular AMD, which have prognostic implications for these patients. Incorporating deep learning into the assessment of neovascular AMD eyes holds promise for enhancing clinical management strategies for affected individuals. Conclusion: Several studies have demonstrated effectiveness of deep learning in assessing neovascular AMD patients and this has a promising role in the assessment of these patients.

Potential Risk Factors for Ocular Pain in Patients Undergoing Multiple Intravitreal Injections of Anti-Vascular Endothelial Growth Factor

Purpose

To assess ocular pain in patients undergoing multiple intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) who have previous factors that may influence pain sensitivity.

Methodology

This is a prospective, observational, case series study involving patients who underwent multiple (≥3) pro re nata intravitreal injections of ranibizumab or aflibercept to treat any cause of chorioretinal vascular disease. Ocular pain was assessed by the numerical analog scale during intravitreal injection. For this study, the main variable was ocular pain and the secondary variables included age, sex, previous history of glaucoma, primary retinal vascular disease, severe dry eye history, trigeminal pain, scleral buckle surgery, collagen diseases, fibromyalgia, severe migraine history, pars plana vitrectomy, scleral thickness measurements, and type of anti-VEGF.

Results

In a total of 894 patients, 948 eyes (4822 intravitreal injections), 793 patients (88.6%) had ocular pain sensitivity between no pain to mild pain, 80 patients (8.9%) had moderate ocular pain, 15 patients (1.6%) had severe ocular pain, and 6 patients (0.7%) had extremely severe ocular pain. Patients with severe dry eye (p = 0.01) and previous history of scleral buckle surgery (p = 0.01) showed a significant correlation with ocular pain during intravitreal injection. Pars plana scleral thickness (>550 um) and diabetic neuropathy were associated with ocular pain but did not meet the criteria for statistical significance (p = 0.09 and p = 0.06, respectively).

Conclusion

Dry eye and prior scleral buckle surgery may contribute to pain associated with intravitreal injection. These issues should be taken into consideration in patients undergoing multiple intravitreal injections.

Macular and Optic Disc Perfusion Changes After Silicone Oil Removal Using Optical Coherence Tomography Angiography: A Prospective Study

AIM

The aim of this study was to prospectively evaluate the changes in macular and optic disc microvascular structures in patients who underwent silicone oil (SO) removal.

MATERIALS AND METHODS

A total of 28 patients scheduled for unilateral SO removal were included in the study. Their fellow eyes served as controls. Optical coherence tomography angiography (OCTA) of the retina (6.0 mm) and disc (4.5 mm) was performed one day before SO removal, and then at 1 week and 1, 3, 6, and 12 months postoperatively. All analyses were conducted using the R programming language, with a p-value <0.05 considered statistically significant.

RESULTS

After silicone oil removal, statistically significant changes were observed in the flow in the outer retina and radial peripapillary capillary (RPC) density for small and all vessels inside the disc. Statistically significant differences between the intervention and control groups were noted in vessel density in both the superficial and deep capillary plexuses and RPC density for small and all vessels.

CONCLUSION

Changes in macular vessel density and radial peripapillary capillary density were observed after SO removal. The latter changes appear to improve after the first postoperative month and continue until the first postoperative year. Notably, these changes were significant between the first postoperative week and 6 and 12 postoperative months (p = 0.0263 and p = 0.021, respectively). Best corrected visual acuity (BCVA) is likely associated with these parameters, indicating that improvement may be observed even one year following SO removal.

Structural and clinical changes in previously treated type 1 macular neovascularization in non-responder AMD eyes switched to brolucizumab

PURPOSE

To examine structural and clinical changes in previously treated type 1 macular neovascularization (MNV) in non-responder age-related macular degeneration (nAMD) eyes switched to brolucizumab. Subretinal hyper-reflective material (SHRM), intraretinal (IRF) and subretinal fluid (SRF) presence, fibrovascular-pigment epithelium detachment (PED) height and central macular thickness (CMT) variation were analyzed using optical coherence tomography (OCT).

METHODS

In this prospective study all patients underwent a complete ophthalmological evaluation including structural OCT at baseline (T0), one month (T1), three (T2), four (T3) and six months after switching to brolucizumab treatment (T4). Non-responder criterion was the persistence of IRF and SRF. Moreover, CMT and BCVA had shown worsening or no improvement before switching to brolucizumab. Clinical function and structural activity biomarkers were measured at each visit and changes were analyzed. P value <0.05 was considered statistically significant.

RESULTS

Twenty eyes of twenty patients were enrolled. All the structural variables examined during the follow-up showed significant reductions. Decreases in IRF, SRF and PED were already significant at T1 (p < 0.05). SHRM was significantly reduced at T2 (p < 0.05). Structural biomarkers were absent at T3. At T4, all biomarkers remained stable while SHRM was no longer detectable in 18 patients. Changes in visual acuity from baseline to T4 were not significant.

CONCLUSION

This short-term experience highlights that brolucizumab might be considered an effective treatment option in nAMD with type 1 MNV, as it can promote a reduction of structural activity biomarkers.

Bacillary layer detachment as an inflammatory biomarker in toxoplasmosis retinochoroiditis: serial evolution on optical coherence tomography

We describe the clinical course and serial evolution of bacillary layer detachment (BALAD) on optical coherence tomography (OCT) in toxoplasmosis retinochoroiditis and its importance as an inflammatory biomarker. Colour fundus photography and swept-source OCT of the BALAD were done at the time of presentation and subsequently at 1 week, 2 weeks, 4 weeks and at 11 weeks. Treatment involved oral trimethoprim (160 mg) + sulphamethoxazole (800 mg) two times per day, started at presentation for 2 months. Oral prednisolone was started after 1 week at a dose of 50 mg a day and tapered weekly over the next 5 weeks. The BALAD initially increased after starting treatment with trimethoprim-sulphamethoxazole and regressed within 1 week after initiation of oral prednisolone. Best corrected visual acuity improved to 20/40 from 20/160 at presentation (Snellen equivalent). This suggests that BALAD is an indicator of an acute inflammatory event and the accumulated fluid is secondary to retinal and choroidal inflammation.

Predicting OCT biological marker localization from weak annotations

Recent developments in deep learning have shown success in accurately predicting the location of biological markers in Optical Coherence Tomography (OCT) volumes of patients with Age-Related Macular Degeneration (AMD) and Diabetic Retinopathy (DR). We propose a method that automatically locates biological markers to the Early Treatment Diabetic Retinopathy Study (ETDRS) rings, only requiring B-scan-level presence annotations. We trained a neural network using 22,723 OCT B-Scans of 460 eyes (433 patients) with AMD and DR, annotated with slice-level labels for Intraretinal Fluid (IRF) and Subretinal Fluid (SRF). The neural network outputs were mapped into the corresponding ETDRS rings. We incorporated the class annotations and domain knowledge into a loss function to constrain the output with biologically plausible solutions. The method was tested on a set of OCT volumes with 322 eyes (189 patients) with Diabetic Macular Edema, with slice-level SRF and IRF presence annotations for the ETDRS rings. Our method accurately predicted the presence of IRF and SRF in each ETDRS ring, outperforming previous baselines even in the most challenging scenarios. Our model was also successfully applied to en-face marker segmentation and showed consistency within C-scans, despite not incorporating volume information in the training process. We achieved a correlation coefficient of 0.946 for the prediction of the IRF area.

Deep learning in optical coherence tomography: Where are the gaps?

Optical coherence tomography (OCT) is a non-invasive optical imaging modality, which provides rapid, high-resolution and cross-sectional morphology of macular area and optic nerve head for diagnosis and managing of different eye diseases. However, interpreting OCT images requires experts in both OCT images and eye diseases since many factors such as artefacts and concomitant diseases can affect the accuracy of quantitative measurements made by post-processing algorithms. Currently, there is a growing interest in applying deep learning (DL) methods to analyse OCT images automatically. This review summarises the trends in DL-based OCT image analysis in ophthalmology, discusses the current gaps, and provides potential research directions. DL in OCT analysis shows promising performance in several tasks: (1) layers and features segmentation and quantification; (2) disease classification; (3) disease progression and prognosis; and (4) referral triage level prediction. Different studies and trends in the development of DL-based OCT image analysis are described and the following challenges are identified and described: (1) public OCT data are scarce and scattered; (2) models show performance discrepancies in real-world settings; (3) models lack of transparency; (4) there is a lack of societal acceptance and regulatory standards; and (5) OCT is still not widely available in underprivileged areas. More work is needed to tackle the challenges and gaps, before DL is further applied in OCT image analysis for clinical use.

Evaluation of the efficacy of anti-vascular endothelial growth factors in diabetic macular edema with retinal inner and outer layers disorganization

AIMS

This study aims to compare the effectiveness of treatment between anti-vascular endothelial growth factor (anti-VEGF) agents in diabetic macular edema (DME) patients with disorganization of retinal inner layers (DRIL). Epiretinal membrane, serous macular detachment, ellipsoid zone (EZ) disorder, external limiting membrane (ELM) disorder, and hyperreflective foci were also examined.

METHODS

Patients treated for DME and also had DRIL were included in the study. The study design was retrospective and cross-sectional. The complete ophthalmologic records and imaging were scanned at the beginning, 3rd-month, 6th-month, and 12th-month follow-up, and the treatments administered were recorded. Anti-VEGF agents administered to the patients were examined in three groups: bevacizumab, ranibizumab, and aflibercept.

RESULT

A total of 141 eyes of 100 patients were included in our study. One hundred and fifteen eyes (81.6%) had a BCVA of 0, 5, or less at the beginning. There was no statistically significant difference between the three groups regarding initial BCVA and CMT and the change in BCVA and CMT at the beginning and the 12th month (p > 0.05). There was a negative correlation between EZ and ELM disorders in patients and the change in BCVA at 12 months (r: 0.45 p < 0.001, r: 0.32 p < 0.001, respectively). The number of injections over five was positively correlated with the change in CMT but not with BCVA (r: - 2.35 p = 0.005 and r: 0.147 p = 0.082, respectively).

CONCLUSIONS

No statistically significant difference was found between anti-VEGF agents when treating DME patients with DRIL. In addition, we have shown that anatomically better results were obtained in those who had five or more injections, although not in terms of BCVA.

Drusen morphometrics on optical coherence tomography in eyes with age-related macular degeneration and normal aging

PURPOSE

To compare drusen size metrics (apical height and basal width) on optical coherence tomography (OCT) B-scans with their size assessed on color photos in eyes with age-related macular degeneration (AMD) and normal aging.

METHODS

A total of 508 drusen were evaluated in this analysis. Flash color fundus photos (CFP), infrared reflectance (IR) images, and OCT B-scans obtained at the same visit were evaluated. Individual drusen were identified on CFPs and the diameters of the drusen were measured in planimetric grading software. CFPs were manually registered to the IR image with their corresponding OCT volume. After confirming correspondence between the CFP and OCT, the apical height and basal width of the same drusen were measured on OCT B-scans.

RESULTS

Drusen were divided into small, medium, large, and very large categories based on their diameter on the CFP images (< 63, 63 to 124, 125 to 249, and [Formula: see text] 250 μm, respectively). The OCT apical height of small drusen on CFP ranged from 20 to 31 μm, while medium drusen ranged from 31 to 46 μm, large drusen ranged from 45 μm to 111 µm, and very large drusen ranged from 55 μm to 208 μm. The OCT basal width measured < 99 μm in small drusen, from 99 to 143 μm in medium drusen, from 141 to 407 µm in large drusen, and > 209 µm in very large drusen.

CONCLUSION

Drusen of different size categories on color photographs may also be separated according to their apical height and basal width on OCT. The apical height and basal width ranges defined in this analysis may be of value in the design of an OCT-based grading scale for AMD.

Dispositional mindfulness and BIS/BAS up-close: can the self-regulation of people be seen in the eyes?

Introduction

Pigmentation in animal models is related to behavioral regulation and development, suggesting that both may belong to the same biological system. However, such models are poorly documented in humans. The current study explored personality and group differences in self-regulation among healthy subjects and their specific eye structures (contraction furrows and pigment spots). Three objectives were proposed: to analyze statistical differences in dispositional mindfulness (DM), behavioral inhibition system (BIS), and behavioral approach system (BAS) among subjects with a specific iris type of contraction furrows and pigment spots.

Methods

The study sample consisted of 194 university students. One month after taking photographs of their eyes, the students completed the online scales of DM, BIS, and BAS.

Results

DM was negatively related to pigment spots (rs = -0.193; p < 0.01). Cluster analysis of the iris structures converged at a four-cluster solution. The cluster types 2 (absence of pigment spots and contraction furrows extending 8/10 of iris circle or more) and 3 (one or more pigment spots and contraction furrows extending 8/10 of iris circle or more) significantly differed in DM with a small effect size (F = 3.37; p = 0.021; η2 = 0.051). Participants with contraction furrows (8/10 or more circle extent) and without pigment spots had a significantly higher DM than those with pigment spots. No significant differences existed among the iris types in BIS/BAS.

Discussion

Future research directions are suggested.

A multidisciplinary approach to inherited retinal dystrophies from diagnosis to initial care: a narrative review with inputs from clinical practice

BACKGROUND

Non-syndromic inherited retinal dystrophies (IRDs) such as retinitis pigmentosa or Leber congenital amaurosis generally manifest between early childhood and late adolescence, imposing profound long-term impacts as a result of vision impairment or blindness. IRDs are highly heterogeneous, with often overlapping symptoms among different IRDs, and achieving a definite diagnosis is challenging. This narrative review provides a clinical overview of the non-syndromic generalized photoreceptor dystrophies, particularly retinitis pigmentosa and Leber congenital amaurosis. The clinical investigations and genetic testing needed to establish a diagnosis are outlined, and current management approaches are discussed, focusing on the importance of the involvement of an interdisciplinary team from diagnosis and initial care to long-term follow-up and support.

RESULTS

The effective management of IRDs requires a multidisciplinary, and ideally interdisciplinary, team of experts knowledgeable about IRDs, with experienced professionals from fields as diverse as ophthalmology, neuropsychiatry, psychology, neurology, genetics, orthoptics, developmental therapy, typhlology, occupational therapy, otolaryngology, and orientation and mobility specialties. Accurate clinical diagnosis encompasses a range of objective and subjective assessments as a prerequisite for the genetic testing essential in establishing an accurate diagnosis necessary for the effective management of IRDs, particularly in the era of gene therapies. Improvements in genome sequencing techniques, such as next-generation sequencing, have greatly facilitated the complex process of determining IRD-causing gene variants and establishing a molecular diagnosis. Genetic counseling is essential to help the individual and their family understand the condition, the potential risk for offspring, and the implications of a diagnosis on visual prognosis and treatment options. Psychological support for patients and caregivers is important at all stages of diagnosis, care, and rehabilitation and is an essential part of the multidisciplinary approach to managing IRDs. Effective communication throughout is essential, and the patient and caregivers' needs and expectations must be acknowledged and discussed.

CONCLUSION

As IRDs can present at an early age, clinicians need to be aware of the clinical signs suggesting visual impairment and follow up with multidisciplinary support for timely diagnoses to facilitate appropriate therapeutic or rehabilitation intervention to minimize vision loss.

Prognostic Optical Coherence Tomography Biomarkers in Neovascular Age-Related Macular Degeneration

Optical coherence tomography has revolutionized the diagnosis and management of neovascular age-related macular degeneration. OCT-derived biomarkers have the potential to further guide therapeutic advancements with anti-vascular endothelial growth factor; however, the clinical convergence between these two tools remains suboptimal. Therefore, the aim of this review of literature was to examine the current data on OCT biomarkers and their prognostic value. Thirteen biomarkers were analyzed, and retinal fluid had the strongest-reported impact on clinical outcomes, including visual acuity, clinic visits, and anti-VEGF treatment regimens. In particular, intra-retinal fluid was shown to be associated with poor visual outcomes. Consistencies in the literature with regard to these OCT prognostic biomarkers can lead to patient-specific clinical decision making, such as early-initiated treatment and proactive monitoring. An integrated analysis of all OCT components in combination with new efforts toward automated analysis with artificial intelligence has the potential to further improve the role of OCT in nAMD therapy.

Retinitis Pigmentosa: Current Clinical Management and Emerging Therapies

Retinitis pigmentosa (RP) comprises a group of inherited retinal dystrophies characterized by the degeneration of rod photoreceptors, followed by the degeneration of cone photoreceptors. As a result of photoreceptor degeneration, affected individuals experience gradual loss of visual function, with primary symptoms of progressive nyctalopia, constricted visual fields and, ultimately, central vision loss. The onset, severity and clinical course of RP shows great variability and unpredictability, with most patients already experiencing some degree of visual disability in childhood. While RP is currently untreatable for the majority of patients, significant efforts have been made in the development of genetic therapies, which offer new hope for treatment for patients affected by inherited retinal dystrophies. In this exciting era of emerging gene therapies, it remains imperative to continue supporting patients with RP using all available options to manage their condition. Patients with RP experience a wide variety of physical, mental and social-emotional difficulties during their lifetime, of which some require timely intervention. This review aims to familiarize readers with clinical management options that are currently available for patients with RP.

Correlation Between Imaging Morphological Findings and Laboratory Biomarkers in Patients with Retinal Vein Occlusion

INTRODUCTION

The aim of this study was to investigate the possible correlation between peripheral blood biomarkers and morphological characteristics of retinal imaging in patients with retinal vein occlusion (RVO).

METHODS

Participants in this cross-sectional observational study were 65 consecutive patients (65 eyes) with treatment-naïve RVO, who underwent spectral-domain optical coherence tomography (SD-OCT) and fundus fluorescein angiography (FFA). In addition, peripheral blood samples were taken to evaluate full blood count and biochemical parameters. The association between imaging characteristics and laboratory parameters was examined.

RESULTS

Eyes with subretinal fluid presented significantly higher neutrophil-to-lymphocyte ratios (p = 0.028). Hyperreflective foci on SD-OCT were found to be associated with higher triglyceride levels (p = 0.024). The presence of cysts on SD-OCT was associated with significantly higher triglycerides (p = 0.010). Central subfield thickness (CST) higher than 464 μm was associated with higher lymphocyte count (p = 0.016) and higher urea (p = 0.015). No significant associations were found between laboratory parameters and intraretinal fluid, ellipsoid zone and external limiting membrane condition, or epiretinal membrane and macular ischemia.

CONCLUSIONS

Specific imaging morphological characteristics were found to be associated with laboratory parameters in patients with RVO. These findings may help reveal the pathophysiology of RVO and its correlation with the development of specific clinical signs, while they could guide individualized treatment.

TSSK-Net: Weakly supervised biomarker localization and segmentation with image-level annotation in retinal OCT images

The localization and segmentation of biomarkers in OCT images are critical steps in retina-related disease diagnosis. Although fully supervised deep learning models can segment pathological regions, their performance relies on labor-intensive pixel-level annotations. Compared with dense pixel-level annotation, image-level annotation can reduce the burden of manual annotation. Existing methods for image-level annotation are usually based on class activation maps (CAM). However, current methods still suffer from model collapse, training instability, and anatomical mismatch due to the considerable variation in retinal biomarkers' shape, texture, and size. This paper proposes a novel weakly supervised biomarkers localization and segmentation method, requiring only image-level annotations. The technique is a Teacher-Student network with joint Self-supervised contrastive learning and Knowledge distillation-based anomaly localization, namely TSSK-Net. Specifically, we treat retinal biomarker regions as abnormal regions distinct from normal regions. First, we propose a novel pre-training strategy based on supervised contrastive learning that encourages the model to learn the anatomical structure of normal OCT images. Second, we design a fine-tuning module and propose a novel hybrid network structure. The network includes supervised contrastive loss for feature learning and cross-entropy loss for classification learning. To further improve the performance, we propose an efficient strategy to combine these two losses to preserve the anatomical structure and enhance the encoding representation of features. Finally, we design a knowledge distillation-based anomaly segmentation method that is effectively combined with the previous model to alleviate the challenge of insufficient supervision. Experimental results on a local dataset and a public dataset demonstrated the effectiveness of our proposed method. Our proposed method can effectively reduce the annotation burden of ophthalmologists in OCT images.

OCT-Based Biomarkers are Associated with Systemic Inflammation in Patients with Treatment-Naïve Diabetic Macular Edema

INTRODUCTION

Diabetic macular edema (DME) is one of the major sight-threatening complications of diabetic retinopathy, which is associated with retinal inflammation. However, it is still unknown whether DME is associated with systemic inflammation. The study aimed to investigate the association between systemic inflammatory and optical coherence tomography (OCT) biomarkers in patients with treatment-naïve center-involving diabetic macular edema (DME) and to further explore the role of systemic inflammation in DME.

METHODS

Medical records including clinical characteristics and ophthalmic examinations were collected from patients with treatment-naïve center-involving DME. Systemic inflammation markers including systemic immune-inflammatory index (SII), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) were calculated. OCT biomarkers, including intraretinal cyst (IRC) size, disorganization of retinal inner layers (DRIL), external limiting membrane (ELM)/ellipsoid zone (EZ) integrity, retinal hyperreflective foci (HRF), subretinal fluid (SRF) and vitreomacular (VM) status were evaluated manually. Correlation analysis and multivariable linear regression models were used to investigate the relationship between systemic inflammatory markers and OCT biomarkers.

RESULTS

A total of 82 patients with treatment-naïve center-involving DME were included. The number of HRF on OCT was correlated with SII, NLR, and PLR and positively associated with SII (p < 0.001) in both univariate and multivariate linear regression analyses. The differences remained largely the same during subgroup analysis controlling DM duration, SRF, and ELM/EZ integrity. No significant association was observed between other OCT biomarkers and blood inflammatory markers.

CONCLUSION

Retinal HRF in diabetic macular edema is associated with blood inflammatory markers, which supports the theory of HRF's inflammatory nature and emphasizes the important role of inflammation in DME. SII may be a potential marker for DME treatment decisions.

A prospective, randomized, parallel group, double blind, multicenter study to compare the efficacy, safety and immunogenicity of Lupin's Ranibizumab with Lucentis® in patients with neovascular age-related macular degeneration

Purpose:

The present study compares the efficacy, safety, and immunogenicity of Lupin’s biosimilar ranibizumab with that of Lucentis^® in patients with neovascular age-related macular degeneration.

Methods:

This prospective, double-blind, multi-centric phase-III study was conducted across 19 centers in India. A total of 202 patients with neovascular age-related macular degeneration were randomized (1:1) to receive either Lupin’s biosimilar ranibizumab or Lucentis^®, 0.5 mg, as an intravitreous injection once every month for 3 months. The primary efficacy endpoint was the proportion of patients who lost fewer than 15 letters from baseline in best-corrected visual acuity. The safety profile included assessment of adverse events, ophthalmic examination, physical and systemic examination, and vital parameters. The immunogenicity assessment was based on evaluation of anti-drug antibodies.

Results:

Overall, 174 patients (87 [86.14%] in each group) completed the study. The demographics and baseline characteristics were comparable between the treatment groups. The proportion of patients losing fewer than 15 letters from baseline best corrected visual acuity score in the study eye was comparable between two groups. The difference between Lupin’s ranibizumab and Lucentis^® for the proportion of patients who lost fewer than 15 letters was within the predefined equivalence margin (intention-to-treat population: 1.0%; 95% confidence interval [CI], −3.3% to 5.4% and per protocol population: 1.2%; 95% CI, −3.2% to 6.4%). The incidence of treatment-emergent adverse events was comparable, and 11 (10.89%) patients in Lupin’s ranibizumab and 19 (18.81%) patients in Lucentis^® group had at least one treatment-emergent adverse event. The immunogenicity incidence as assessed by proportion of patients with positive anti-drug antibodies was numerically lower in Lupin’s ranibizumab (4.95%) than Lucentis^® (12.87%).

Conclusion:

Lupin’s biosimilar ranibizumab demonstrated therapeutic equivalence, desirable safety, and favorable immunogenicity profile compared to Lucentis^®.

The impact of laboratory findings and optical coherence tomography biomarkers on response to intravitreal anti-VEGF treatment in patients with retinal vein occlusion

AIMS

To investigate potential laboratory and imaging biomarkers as treatment response predictors to intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents in patients with retinal vein occlusion (RVO).

METHODS

Participants in this prospective study were 53 patients with treatment naïve macular edema secondary to RVO, treated with intravitreal anti-VEGF agents and followed-up for 12 months. At baseline, all participants underwent best-corrected visual acuity measurement, dilated fundoscopy, optical coherence tomography and fluorescein angiography (FFA), while full blood count and biochemical analysis of various parameters was also performed. At month 12, treatment response was examined and classified as "favorable" or "non-response". Potential associations between laboratory/imaging biomarkers and treatment response were assessed.

RESULTS

Univariate analysis showed that "favorable" response at month 12 after initiation of anti-VEGF treatment was correlated with baseline central subfield thickness (CST) < 464 μm (p < 0.001), absence of subretinal fluid (p = 0.004), absence of hyperreflective foci (HF) (p = 0.004), intact ellipsoid zone (EZ) and external limiting membrane (ELM) (p < 0.001 and p = 0.001, respectively), absence of epiretinal membrane (ERM) (p = 0.020) and absence of macular ischemia on FFA (p < 0.001), while increased monocytes-to-lymphocytes ratio was also associated with "favorable" treatment response (p = 0.010). All other laboratory parameters did not reach statistical significance. However, at the multivariate analysis, EZ and ELM status, HF, macular ischemia and monocytes-to-lymphocytes ratio were found to be independent predictors of treatment response.

CONCLUSIONS

Intact EZ and ELM, absence of HF, absence of macular ischemia and increased monocytes-to-lymphocytes ratio at baseline can predict "favorable" treatment response in patients with treatment naïve macular edema secondary to RVO.

The Impact of Laboratory Findings and Optical Coherence Tomography Biomarkers on Response to Intravitreal Anti-VEGF Treatment in Patients with Diabetic Macular Edema

PURPOSE

To investigate potential laboratory and imaging biomarkers as treatment response predictors to intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents in patients with diabetic macular edema (DME).

METHODS

The study included 36 treatment naïve patients with DME, treated with intravitreal anti-VEGF agents and followed-up for 12 months. At baseline, all participants underwent best-corrected visual acuity (BCVA) measurement, dilated fundoscopy, optical coherence tomography, color fundus photography and fluorescein angiography, while full blood count and biochemical analysis of various parameters was also performed. At month 12, treatment response was examined and classified as "favorable" or "non-response". Potential associations between laboratory/imaging biomarkers and treatment response were assessed.

RESULTS

Univariate analysis showed that favorable response at month 12 after initiation of anti-VEGF treatment was correlated with baseline central subfield thickness (CST)≤405 μm (p < .001), absence of subretinal fluid (p = .034), absence of exudates (p = .041), absence of disorganization of the inner retinal layers (p = .037), intact ellipsoid zone (EZ) and external limiting membrane (ELM) (p < .001 and p = .002, respectively), absence of epiretinal membrane (ERM) (p = .040) and absence of macular ischemia (p = .042), while increased lipoprotein(a) was associated with no treatment response (p = .025). At the multivariate analysis, CST was found to be independent predictor of treatment response, while EZ, ELM and ERM were found to predict treatment response perfectly and they could not be entered in the model.

CONCLUSION

Intact EZ and ELM, absence of ERM and CST≤405 μm at baseline can predict favorable treatment response in patients with treatment naïve DME, while no correlation with baseline laboratory parameters was found.

Findings of uncertain significance by optical coherence tomography (OCT) as prognostic factors in neovascular age-related macular degeneration (nAMD) treated with ranibizumab

Background

Biomarkers hold great promise for personalized medicine as information gained from diagnostic or progression markers can be used to tailor treatment to the individual for highly effective intervention in the disease process.

Methods

The aim of this retrospective study was to evaluate the association between visual outcome and the presence of findings of uncertain significance by optical coherence tomography (OCT) pre and post loading dose in patients with neovascular age-related macular degeneration (nAMD) treated with ranibizumab.

Results

Univariate analysis revealed a higher letter gain in those with presence of onion sign (+ 5.6 ETDRS letters, p = 0.04) absence of prechoroidal cleft (+ 3.7 ETDRS letters, p = 0.04), intraretinal pseudocysts (+4.8 ETDRS letters, p = 0.002), subretinal pseudocysts (+ 4.6 ETDRS letters, p = 0.005) and choroidal caverns (+ 4.4 ETDRS, letters p = 0.0065).

Conclusions

The presence of prechoroidal cleft, intraretinal and subretinal pseudocysts and choroidal caverns were associated with lower visual gains. Moreover, we found that the onion sign is related as a biomarker of good prognostics.

Trial registration Registration number: 2021R13B2. Date of registration: 01/05/2020

The effect of transverse ocular magnification adjustment on macular thickness profile in different refractive errors in community-based adults

Purpose

Changes in retinal thickness are common in various ocular diseases. Transverse magnification due to differing ocular biometrics, in particular axial length, affects measurement of retinal thickness in different regions. This study evaluated the effect of axial length and refractive error on measured macular thickness in two community-based cohorts of healthy young adults.

Methods

A total of 2160 eyes of 1247 community-based participants (18–30 years; 23.4% myopes, mean axial length = 23.6mm) were included in this analysis. Macular thickness measurements were obtained using a spectral-domain optical coherence tomography (which assumes an axial length of 24.385mm). Using a custom program, retinal thickness data were extracted at the 9 Early Treatment of Diabetic Retinopathy Study (ETDRS) regions with and without correction for transverse magnificent effects, with the corrected measurements adjusting according to the participant’s axial length. Linear mixed models were used to analyse the effect of correction and its interaction with axial length or refractive group on retinal thickness.

Results

The raw measures (uncorrected for axial length) underestimated the true retinal thickness at the central macula, while overestimating at most non-central macular regions. There was an axial length by correction interaction effect in all but the nasal regions (all p<0.05). For each 1mm increase in axial length, the central macular thickness is overestimated by 2.7–2.9μm while thicknesses at other regions were underestimated by 0.2–4.1μm. Based on the raw thickness measurements, myopes have thinner retinas than non-myopes at most non-central macular. However, this difference was no longer significant when the corrected data was used.

Conclusion

In a community-based sample, the raw measurements underestimate the retinal thickness at the central macula and overestimate the retinal thickness at non-central regions of the ETDRS grid. The effect of axial length and refractive error on retinal thickness is reduced after correcting for transverse magnification effects resulting from axial length differences.

Correlating optical coherence tomography biomarkers with visual acuity in nigerian retinitis pigmentosa patients

Background

Spectral Domain Optical Coherence Tomography (SD-OCT) has been used for imaging retinitis pigmentosa (RP) eyes and provides useful information on microstructural changes.

Aim

To review SD-OCT findings and correlate the central foveal thickness (CFT), outer nuclear layer (ONL), external limiting membrane (ELM), and ellipsoid zone (EZ) with visual function in nonsyndromic RP eyes.

Patients and Methods

A multicenter, retrospective review of records from consecutive eyes diagnosed to have RP. Biodata, systemic disease, visual acuity, lens status, intraocular pressure, and SD-OCT images were examined. The CFT was categorized into normal (250-299 microns), atrophic (0-249 microns), and edematous (≥300 microns). The ONL, ELM, and EZ within the subfoveal area was assessed and rated as normal, reduced (if less than normal), or absent (if missing). The status of these biomarkers was correlated with visual acuity and statistical analysis performed using Pearson Chi², P < 0.05. In addition, the vitreomacular interface was examined for the presence of vitreomacular traction (VMT), vitreomacular adhesion (VMA), and epiretinal membrane (ERM).

Results

Fifty-two RP eyes of 27 patients had SD-OCT images that were used for study analysis. There were 17 males and 10 females; 52% of participants were between 31 and 50 years (age range: 22-77 years). An atrophic retina was the most common finding in 42 eyes (81%); the average CFT in the atrophic group was 175 microns (range: 111-245 microns). There were three eyes with cystoid macular edema, and seven eyes were normal. For the OCT biomarkers, a reduction in ONL and ELM occurred in 69% and 46% of eyes, respectively, while an absence was the most common EZ finding (in 50% of eyes). There was a significant correlation between the presence or absence of the three biomarkers and presenting vision: ONL, ELM, and EZ with P values of 0.000, 0.006, and 0.011, respectively. The CFT had no significant correlation with vision; P = 0.522. Other findings on OCT include ERM 17%, VMA 6%, and VMT 2%.

Conclusion

This report supports the notion that OCT image reporting on physical retinal structure in RP eyes can be used to predict disease effects on vision. A prospective study to better quantify the degree of structural change and correlate with the degree of functional loss is required for RP gene types in Nigerians and black Africans.

Methanol-induced optic neuropathy: a still-present problem

Methanol-induced optic neuropathy (Me-ION) is a serious condition that may result in long-term or irreversible visual impairment or even blindness secondary to damage and loss of function of the optic nerve and retina. Me-ION shows a tendency to occur as mass poisonings around the world with a clear predilection for poor societies in developing countries. The main mechanism underlying the molecular basis of Me-ION is the inhibition of the mitochondrial oxidative phosphorylation process through the binding of the toxic metabolite of methanol—formic acid—with the key enzyme of this process—cytochrome c oxidase. However, other mechanisms, including damage to the eye tissues by oxidative stress causing the intensification of the oxidative peroxidation process with the formation of cytotoxic compounds, as well as an increase in the synthesis of pro-inflammatory cytokines and influence on the expression of key proteins responsible for maintaining cell homeostasis, also play an important role in the pathogenesis of Me-ION. Histopathological changes in the eye tissues are mainly manifested as the degeneration of axons and glial cells of the optic nerve, often with accompanying damage of the retina that may involve all its layers. Despite the development of therapeutic approaches, persistent visual sequelae are seen in 30–40% of survivors. Thus, Me-ION continues to be an important problem for healthcare systems worldwide.

The role of inflammation and neurodegeneration in diabetic macular edema

The pathogenesis of diabetic macular edema (DME) is complex. Persistently high blood glucose activates multiple cellular pathways and induces inflammation, oxidation stress, and vascular dysfunction. Retinal ganglion cells, macroglial and microglial cells, endothelial cells, pericytes, and retinal pigment epithelium cells are involved. Neurodegeneration, characterized by dysfunction or apoptotic loss of retinal neurons, occurs early and independently from the vascular alterations. Despite the increasing knowledge on the pathways involved in DME, only limited therapeutic strategies are available. Besides antiangiogenic drugs and intravitreal corticosteroids, alternative therapeutic options tackling inflammation, oxidative stress, and neurodegeneration have been considered, but none of them has been currently approved.

Human iPS cell derived RPE strips for secure delivery of graft cells at a target place with minimal surgical invasion

Several clinical studies have been conducted into the practicality and safety of regenerative therapy using hESC/iPSC-retinal pigment epithelium (RPE) as a treatment for the diseases including age-related macular degeneration. These studies used either suspensions of RPE cells or an RPE cell sheet. The cells can be injected using a minimally invasive procedure but the delivery of an intended number of cells at an exact target location is difficult; cell sheets take a longer time to prepare, and the surgical procedure is invasive but can be placed at the target area. In the research reported here, we combined the advantages of the two approaches by producing a quickly formed hiPSC-RPE strip in as short as 2 days. The strip readily expanded into a monolayer sheet on the plate, and after transplantation in nude rats, it showed a potency to partly expand with the correct apical/basal polarity in vivo, although limited in expansion area in the presence of healthy host RPE. The strip could be injected into a target area in animal eyes using a 24G canula tip.

Association between Retinal Thickness Variability and Visual Acuity Outcome during Maintenance Therapy Using Intravitreal Anti-Vascular Endothelial Growth Factor Agents for Neovascular Age-Related Macular Degeneration

Previous studies based on clinical trial data have demonstrated that greater fluctuations in retinal thickness during the course of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy for neovascular age-related macular degeneration (nAMD) is associated with poorer visual acuity outcomes. However, it was unclear whether similar findings would be observed in real-world clinical settings. This study aimed to evaluate the association between retinal thickness variability and visual outcomes in eyes receiving anti-VEGF therapy for nAMD using pro re nata treatment regimen. A total of 64 eyes which received intravitreal anti-VEGF therapy (bevacizumab, ranibizumab or aflibercept) for the treatment of nAMD were evaluated. Variability in spectral-domain optical coherence tomography (OCT) central subfield thickness (CST) was calculated from the standard deviation (SD) values of all follow-up visits after three loading doses from month 3 to month 24. Eyes were divided into quartiles based on the OCT CST variability values and the mean best-corrected visual acuity values at 2 years were compared. At baseline, the mean ± SD logMAR visual acuity and CST were 0.59 ± 0.39 and 364 ± 113 µm, respectively. A significant correlation was found between CST variability and visual acuity at 2 years (Spearman's ρ = 0.54, p < 0.0001), indicating that eyes with lower CST variability had better visual acuity at 2 years. Eyes with the least CST variability were associated with the highest mean visual acuity improvement at 2 years (quartile 1: +9.7 letters, quartile 2: +1.1 letters, quartile 3: -2.5 letters, quartile 4: -9.5 letters; p = 0.018). No significant difference in the number of anti-VEGF injections was found between the four CST variability quartile groups (p = 0.21). These findings showed that eyes undergoing anti-VEGF therapy for nAMD with more stable OCT CST variability during the follow-up period were associated with better visual outcomes. Clinicians should consider adopting treatment strategies to reduce CST variability during the treatment course for nAMD.

Framework for quantitative three-dimensional choroidal vasculature analysis using optical coherence tomography

Choroidal vasculature plays an important role in the pathogenesis of retinal diseases, such as myopic maculopathy, age-related macular degeneration, diabetic retinopathy, central serous chorioretinopathy, and ocular inflammatory diseases. Current optical coherence tomography (OCT) technology provides three-dimensional visualization of the choroidal angioarchitecture; however, quantitative measures remain challenging. Here, we propose and validate a framework to segment and quantify the choroidal vasculature from a prototype swept-source OCT (PLEX Elite 9000, Carl Zeiss Meditec, USA) using a 3×3 mm scan protocol centered on the macula. Enface images referenced from the retinal pigment epithelium were reconstructed from the volumetric data. The boundaries of the choroidal volume were automatically identified by tracking the choroidal vessel feature structure over the depth, and a selective sliding window was applied for segmenting the vessels adaptively from attenuation-corrected enface images. We achieved a segmentation accuracy of 96% ± 1% as compared with manual annotation, and a dice coefficient of 0.83 ± 0.04 for repeatability. Using this framework on both control (0.00 D to -2.00 D) and highly myopic (-8.00 D to -11.00 D) eyes, we report a decrease in choroidal vessel volume (p<0.001) in eyes with high myopia.

OCT Biomarkers in Neovascular Age-Related Macular Degeneration: A Narrative Review

Age-related macular degeneration (AMD) is the leading cause of legal blindness in elderly people. Neovascular AMD (nAMD) is responsible for the majority of cases of severe visual loss in eyes with AMD. Optical coherence tomography (OCT) is the most widely used technology for the diagnosis and follow-up of nAMD patients, which is widely used to study and guide the clinical approach, as well as to predict and evaluate treatment response. The aim of this review is to describe and analyze various structural OCT-based biomarkers, which have practical value during both initial assessment and treatment follow-up of nAMD patients. While central retinal thickness has been the most common and one of the first OCT identified biomarkers, today, other qualitative and quantitative biomarkers provide novel insight into disease activity and offer superior prognostic value and better guidance for tailored therapeutic management. The key importance of retinal fluid compartmentalization (intraretinal fluid, subretinal fluid, and subretinal pigment epithelium (RPE) fluid) will be discussed firstly. In the second part, the structural alterations of different retinal layers in various stages of the disease (photoreceptors layer integrity, hyperreflective dots, outer retinal tubulations, subretinal hyperreflective material, and retinal pigment epithelial tears) will be analyzed in detail. The last part of the review will focus on how alterations of the vitreoretinal interface (vitreomacular adhesion and traction) and of the choroid (sub-RPE hyperreflective columns, prechoroidal clefts, choroidal caverns, choroidal thickness and choroidal volume, and choroidal vascular index) interact with nAMD progression. OCT technology is evolving very quickly, and new retinal biomarkers are continuously described. This up-to-date review article provides a comprehensive description on how structural OCT-based biomarkers provide a valuable tool to monitor the progression of the disease and the treatment response in nAMD patients. Thus, in this perspective, clinicians will be able to allocate hospital resources in the best possible way and tailor treatment to the individual patient's needs.

Macular Thickness Profile and Its Association With Best-Corrected Visual Acuity in Healthy Young Adults

Purpose

To describe the thickness profiles of the full retinal and outer retinal layers (ORL) at the macula in healthy young adults, and associations with best-corrected visual acuity (BCVA).

Methods

In total, 1604 participants (19-30 years) underwent an eye examination that included measurements of their BCVA, axial length, and autorefraction. The retinal thickness at the foveal pit and at the nine Early Treatment of Diabetic Retinopathy Study macular regions (0.5-mm radius around the fovea, and superior, inferior, temporal, and nasal quadrants of the inner and outer rings of the macula) were obtained using spectral-domain optical coherence tomography imaging. A custom program was used to correct for transverse magnification effects because of different axial lengths.

Results

The median full retinal and ORL thicknesses at the central macula were 285 µm and 92 µm. The full retina was thinnest centrally and thickest at the inner macula ring, whereas the ORL was thickest centrally and gradually decreased in thickness with increasing eccentricity. There was no association between axial length and the full retinal or ORL thickness. Increased thicknesses of the full retina at the central macula was associated with better BCVA; however, the effect size was small and not clinically significant.

Conclusions

This article mapped the full retinal and ORL thickness profile in a population-based sample of young healthy adults.

Translational Relevance

Thickness values presented in this article could be used as a normative reference for future studies on young adults and in clinical practice.

Malfunction of outer retinal barrier and choroid in the occurrence and progression of diabetic macular edema

Diabetic macular edema (DME) is the most common cause of vision loss in diabetic retinopathy, affecting 1 in 15 patients with diabetes mellitus (DM). The disruption of the inner blood-retina barrier (BRB) has been largely investigated and attributed the primary role in the pathogenesis and progression in DME, but there is increasing evidence regarding the role of outer BRB, separating the RPE from the underlying choriocapillaris, in the occurrence and evolution of DME. The development of novel imaging technologies has led to major improvement in the field of in vivo structural analysis of the macula allowing us to delve deeper into the pathogenesis of DME and expanding our vision regarding this condition. In this review we gathered the results of studies that investigated specific outer BRB optical coherence tomography parameters in patients with DM with the aim to outline the current status of its role in the pathogenesis and progression of DME and identify new research pathways contributing to the advancement of knowledge in the understanding of this condition.

ASSESSMENT OF EARLY CHANGES IN SPECTRAL DOMAIN-OPTICAL COHERENCE TOMOGRAPHY AFTER INITIATION OF TREATMENT WITH INTRAVITREAL AFLIBERCEPT (EYLEA) OVER A 12-WEEK PERIOD FOR PATIENTS WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: A Multicenter French Study (START)

PURPOSE

To assess early changes in spectral-domain optical coherence tomography during the loading phase with intravitreal aflibercept therapy in patients with neovascular age-related macular degeneration.

METHODS

In this prospective, open-label, single-arm, multicenter study, patients with neovascular age-related macular degeneration, who were antivascular endothelial growth factor treatment-naïve, received three monthly initial doses of intravitreal aflibercept 2 mg. The primary outcome was the proportion of patients with dry spectral-domain optical coherence tomography at 12 weeks, defined as an absence of intraretinal edema, intraretinal cysts, subretinal fluid, and subretinal pigment epithelium fluid.

RESULTS

Fifty eyes of 50 patients were investigated. At 12 weeks, 34.0% (17/50) had dry spectral-domain optical coherence tomography. Marked reductions were observed for all other spectral-domain optical coherence tomography parameters. The mean macular central thickness fell significantly from 463.2 ± 184.3 µm at baseline to 288.9 ± 76.8 µm at Week 12 (P < 0.0001). The mean best-corrected visual acuity also improved significantly from 61.0 ± 16.0 letters at baseline to 66.6 ± 19.0 letters at Week 12 (P = 0.0006).

CONCLUSION

The anatomic and functional outcomes improved over the 12-week study period. All outcome variables peaked after the third aflibercept injection, confirming the benefit of three initial doses.

[Biomarkers in full-thickness and lamellar defects of the macula]

BACKGROUND

Biomarkers are characteristic biological measurable signs and objective parameters to detect the state of health. Besides functional and temporal factors, imaging biomarkers play an increasingly important role. In full-thickness and lamellar defects of the macula numerous imaging parameters have been described. This knowledge resulted in new classifications for both clinical pictures, which are based on important biomarkers of these clinical pictures and characteristic features of described subtypes.

METHODS

Imaging biomarkers for full-thickness and lamellar macular defects are described with respect to the classification and their functional prognostic importance. The importance of these biomarkers is presented.

RESULTS

The current classification of full-thickness and lamellar macular defects is based on structural biomarkers. Biomarkers are important for prognostic and therapeutic evaluation and they have an impact on the surgical strategy. There are various surgical strategies for treatment of full-thickness macular holes depending on the size of the foramen and other biomarkers. The inverted ILM flap technique improves the closure rate of large macular holes. In lamellar macular holes showing signs of progression an early surgical intervention results in a good anatomical and functional prognosis.

CONCLUSION

Multimodal diagnostics provide important preoperative, intraoperative, and postoperative features for macular holes and lamellar macular holes, which are essential biomarkers for the exact classification, the therapeutic strategy and for assessment of the prognosis.

Correlation between Imaging Morphological Findings and Laboratory Biomarkers in Patients with Diabetic Macular Edema

PURPOSE

To investigate the potential association between peripheral blood biomarkers and morphological characteristics of retinal imaging in patients with diabetic macular edema (DME).

METHODS

Participants in this cross-sectional study were 36 consecutive patients (36 eyes) with treatment-naïve DME, who underwent spectral domain-optical coherence tomography (SD-OCT), fundus photography, and fundus fluorescein angiography (FFA). In addition, peripheral blood samples were taken to evaluate full blood count and biochemical parameters. Correlation between imaging characteristics and laboratory parameters was examined.

RESULTS

Eyes with central subfield thickness greater than 405 μm presented significantly higher neutrophils/lymphocytes (p = 0.043) and higher lipoprotein (a) compared to eyes with CST < 405 μm (p = 0.003). Presence of hyperreflective foci on SD-OCT was associated with significantly higher white blood cell count (p = 0.028). Ellipsoid zone disruption was associated with significantly lower hematocrit (p = 0.012), hemoglobin (p = 0.009), and red blood cell count (p = 0.026), as well as with higher lipoprotein (a) (p = 0.015). Macular ischemia on FFA was associated with significantly higher monocytes (p = 0.027) and monocytes/HDL (p = 0.019). No significant associations were found between laboratory parameters and subretinal fluid, intraretinal fluid, exudates, cysts, disorganization of inner retinal layers, epiretinal membrane, and external limiting membrane condition.

CONCLUSION

Specific imaging morphological characteristics were found to be associated with laboratory parameters in patients with DME. These findings may shed light on the pathophysiology of DME and its correlation with the development of specific clinical signs.

Retinal relaxation following membrane peeling: Effect on vision, central macular thickness, and vector analysis of motion

BACKGROUND

Epiretinal membranes (ERM) form as a result of an inward displacement of retinal structures. Removal of an ERM leads to the outward displacement of retinal vessels and visual improvement.

PURPOSE

The aim of the study was to evaluate the direction and extent of displacement of retinal/superficial vascular structures after a membrane peeling procedure by means of image comparison and in selected cases, a vector analysis of displacement.

METHODOLOGY

Scanning laser ophthalmoscope images of the retina of eyes undergoing ERM peeling were compared before and 6 months after surgery. Stratification was made between prominent and limited displacement, with assessment of visual acuity (VA), and central macular thickness (CMT). In three cases, using the optic nerve as reference, 50 landmarks were chosen within the posterior pole along large and small vascular structures allowing the construction of a vector map of displacement over 1 year.

RESULTS

Nine eyes with prominent and six with limited displacement were assessed. Improvement in VA was similar for both groups, while CMT drop was greatest for the worst group. Vector analysis showed that most vascular movement occurs over the first 6 months, covers most of the posterior retina, is centered around distinct nodes, and may lead to several hundred micrometers of displacement.

CONCLUSIONS

Superficial retinal relaxation has no direct implication on visual recovery. It originates in nodes of retinal contraction. Its extent can be significant, covering most of the posterior pole.

RELEVANCE FOR PATIENTS

A better understanding of retinal relaxation following the peeling of ERM may help better understand when intervention is required and which part of the membrane is critical to surgical success.

[Specific biomarkers of response to antiangiogenic therapy]

Age-related macular degeneration (AMD) and diabetic macular edema (DME) are the main causes of blindness in the elderly and loss of central vision in patients with diabetic retinopathy, respectively. Anti-VEGF therapy is currently the gold standard for treatment of such patients; it has proved its effectiveness in both randomized clinical trials and clinical practice. However, it should be taken into account that the extent of therapeutic response varies depending on individual characteristics of patients, including the presence of biomarkers that predict the therapeutic response. Numerous studies have discovered a variety of biomarkers for patients with DME and AMD, but their reliability differs and not all of them are eligible for predicting the effectiveness of the treatment. Compared to full clinical examination, biomarkers can offer shorter clinical study duration and lower costs. Most of the specific biomarkers for predicting the response to antiangiogenic therapy are identified using optical coherence tomography. The purpose of this article is to provide contemporary data on the diagnosis and treatment of patients depending on the presence of specific biomarkers.

Up-regulation of pro-angiogenic pathways and induction of neovascularization by an acute retinal light damage

The light damage (LD) model was mainly used to study some of the main aspects of age related macular degeneration (AMD), such as oxidative stress and photoreceptor death. Several protocols of light-induced retinal degeneration exist. Acute light damage is characterized by a brief exposure (24 hours) to high intensity light (1000 lux) and leads to focal degeneration of the retina which progresses over time. To date there are not experimental data that relate this model to neovascular events. Therefore, the purpose of this study was to characterize the retina after an acute light damage to assess whether the vascularization was affected. Functional, molecular and morphological investigations were carried out. The electroretinographic response was assessed at all recovery times (7, 60, 120 days after LD). Starting from 7 days after light damage there was a significant decrease in the functional response, which remained low up to 120 days of recovery. At 7 days after light exposure, neo-vessels invaded the photoreceptor layer and retinal neovascularization occurred. Remarkably, neoangiogenesis was associated to the up-regulation of VEGF, bFGF and their respective receptors (VEGFR2 and FGFR1) with the progression of degeneration. These important results indicate that a brief exposure to bright light induces the up-regulation of pro-angiogenic pathways with subsequent neovascularization.

Spectral domain optical coherence tomography based imaging biomarkers for diabetic retinopathy

To evaluate the role of central subfield thickness (CST), cube average thickness (CAT), and cube volume (CV) as imaging biomarkers for severity of diabetic retinopathy within the ETDRS-based grades of retinopathy using spectral domain optical coherence tomography (SD-OCT). This study aims to evaluate the role of macular CST, CAT, and CV on SD-OCT as imaging biomarkers for severity of DR. One hundred ninety-four consecutive cases of type 2 diabetes mellitus were divided according to ETDRS classification: diabetes mellitus without retinopathy (No DR; n = 65), nonproliferative diabetic retinopathy (NPDR; n = 66), and proliferative diabetic retinopathy (PDR; n = 63). Sixty-three healthy controls were included. CST, CAT, and CV were analyzed using SD-OCT. Data were analyzed statistically. Analysis of variance revealed a significant increase in levels of CST, CAT, CV, and LogMAR visual acuity with the increase in severity of DR. Independent t-test revealed significant difference in CST, CAT, and CV between cases with DME and cases without DME. On multivariate linear regression analysis, increase in CST, CAT, and CV were found to indicate the increase in severity of DR. SD-OCT-based imaging biomarkers CST, CAT, and CV are effective tools for documenting the severity of diabetic retinopathy. These imaging biomarkers serve as significant indicators of severity of disease.

Expert-level Automated Biomarker Identification in Optical Coherence Tomography Scans

In ophthalmology, retinal biological markers, or biomarkers, play a critical role in the management of chronic eye conditions and in the development of new therapeutics. While many imaging technologies used today can visualize these, Optical Coherence Tomography (OCT) is often the tool of choice due to its ability to image retinal structures in three dimensions at micrometer resolution. But with widespread use in clinical routine, and growing prevalence in chronic retinal conditions, the quantity of scans acquired worldwide is surpassing the capacity of retinal specialists to inspect these in meaningful ways. Instead, automated analysis of scans using machine learning algorithms provide a cost effective and reliable alternative to assist ophthalmologists in clinical routine and research. We present a machine learning method capable of consistently identifying a wide range of common retinal biomarkers from OCT scans. Our approach avoids the need for costly segmentation annotations and allows scans to be characterized by biomarker distributions. These can then be used to classify scans based on their underlying pathology in a device-independent way.

Choroidal Hyperreflective Foci: A Novel Spectral Domain Optical Coherence Tomography Biomarker in Eyes With Diabetic Macular Edema

PURPOSE

The aim of this study was to examine the hyperreflective dots seen in choroid on spectral domain optical coherence tomography (SDOCT) in eyes with diabetic macular edema (DME) and correlate it with visual acuity.

DESIGN

Consecutive, cross-sectional case series of patients with DME between January 2017 and December 2017.

METHODS

Eyes with DME having central foveal thickness ≥250 μm were included. SDOCT was performed using Spectralis system (Heidelberg Engineering, Germany). Hyperreflective choroidal foci (HCF) were defined as well-circumscribed dots within choroid having reflectivity equal to or higher than adjacent retinal pigment epithelium. HCF were counted manually within 1500 μm of fovea using a horizontal line scan by a blinded observer. Eyes were divided in 3 groups: group A (no HCF), group B (1-10 HCF), and group C (>10 HCF).

RESULTS

One hundred nineteen eyes of 60 DME patients were included. Sixty (50.4%) eyes were in group A, whereas 42 (33.6%) and 17 (14.2%) eyes belonged to group B and group C, respectively. The mean logMAR best corrected visual acuity was significantly lower in group B (0.76 ± 0.79) and C (1.2 ± 0.78) as compared with group A (0.22 ± 0.49) (P = 0.001). Mean central foveal thickness in group A (300.4 ± 122.4 μm) was significantly lower than group B (455.52 ± 209.1 μm) and group C (529.4 ± 196.4 μm) with P value of 0.001.

CONCLUSIONS

The present study describes HCF as novel prognostic SDOCT biomarker in DME whose presence denotes poor visual acuity. Further longitudinal studies are required to substantiate our findings.

Photothermal Optical Coherence Tomography of Anti-Angiogenic Treatment in the Mouse Retina Using Gold Nanorods as Contrast Agents

Purpose

Optical coherence tomography (OCT) is widely used for ocular imaging in clinical and research settings. OCT natively provides structural information based on the reflectivity of the tissues it images. We demonstrate the utility of photothermal OCT (PTOCT) imaging of gold nanorods (GNR) in the mouse retina in vivo in the laser-induced choroidal neovascularization (LCNV) model to provide additional image contrast within the lesion.

Methods

Wild-type C57BL/6 mice were imaged following the intravenous injection of ICAM2-targeted or untargeted GNR. Mice were also imaged following the injection of ICAM2-targeted GNR with or without the additional ocular delivery of a neutralizing monoclonal anti-vascular endothelial growth factor (anti-VEGF) antibody.

Results

Mice cohorts injected with untargeted or ICAM2-targeted GNR demonstrated increased lesion-associated photothermal signal during subsequent imaging relative to phosphate-buffered saline (PBS)-injected controls. Additionally, intravitreal injection of anti-VEGF antibody caused a detectable reduction in the extent of anatomic laser damage and lesion-associated photothermal signal density in mice treated in the LCNV model and injected with ICAM2-targeted GNR.

Conclusions

These experiments demonstrate the ability of PTOCT imaging of GNR to detect anti-VEGF-induced changes in the mouse retina using the LCNV model.

Translational Relevance

This study shows that PTOCT imaging of GNR in the LCNV model can be used to detect clinically relevant, anti-VEGF-induced changes that are not visible using standard OCT systems. In the future this technology could be used to aid in early detection of disease, monitoring disease progress, and assessing its response to therapies.

Ophthalmic medicine regulatory approvals through the European Centralised Procedure, 1999-2017: Clinical efficacy considerations

OBJECTIVES

Regulatory approval of new medicines requires a thorough assessment of the potential clinical benefits and risks. Study end-points are expected to demonstrate a clinically relevant treatment effect that will translate into direct patient benefits. This study sought to review the ophthalmic medicines with European Union-wide approval granted via the Centralised Procedure and characterise the key efficacy end-points underpinning the demonstration of clinical benefit.

METHODS

This study was a retrospective review of published data pertaining to the European regulatory authorisation of centrally approved ophthalmic products between 1999 and 2017, inclusive. All sources and data consulted are in the public domain. European Public Assessment Reports published by the European Medicines Agency were consulted for data concerning the pivotal clinical efficacy studies supporting the applications. Data analyses were descriptive.

RESULTS

The European Medicines Agency have authorised 30 products via the Centralised Procedure between 1999 and 2017. For these products, a total of 24 additional approvals for line extensions or additional therapeutic indications were granted. Four products have been approved for orphan indications, including one approval 'under exceptional circumstances' and one 'Conditional Marketing Authorisation'. Approvals for products in retina (36%) and glaucoma (28%) indications together accounted for the majority of authorisations, with trial end-points predominantly based on visual acuity and intraocular pressure parameters, respectively. Products were also approved for indications in ocular surface disease, inflammation, optic neuropathy and surgical adjuncts, with a range of functional and anatomical end-points.

CONCLUSION

Approvals for ophthalmic medicines have been granted for a range of clinical indications, representing a considerable portion of available major therapeutics for practitioners. Benefit-risk assessments rely on clinical trial data demonstrating a clearly relevant patient benefit.

Image Artifacts in Optical Coherence Tomography Angiography Among Patients With Multiple Sclerosis

PURPOSE

To evaluate artifacts in optical coherence tomography angiography (OCT-A) images of multiple sclerosis (MS) patients and healthy controls.

MATERIALS AND METHODS

This was a prospective cross-sectional study conducted at the Department of Neurology and the Wilmer Eye Institute at Johns Hopkins Hospital. Subjects included patients with an established diagnosis of MS and healthy volunteers. OCT-A was performed using Spectralis® OCT-A prototype, OCT2 (Heidelberg, Germany). The type and frequency of artifacts, the clinical factors associated with them, and their impact on vessel density measurements were assessed.

RESULTS

Overall, 385 images from 102 participants were analyzed. The majority of images (97.1%) had some degree of artifact. The most frequent was motion artifact (96.3%), followed by blinking (51.9%), and loss of focus (25.1%). MS patients were more likely to have any artifact vs. controls (OR [95% CI], 3.83 [1.12-12.92]), and were more likely to have motion artifacts with longer disease duration (OR [95% CI], 1.11 [1.03-1.20]) or history of optic neuritis (OR [95% CI], 4.24 [1.19-15.16]). The relative area occupied by the artifact was found to underestimate vessel density measurements in both MS patients and controls.

CONCLUSIONS

Artifacts are common with OCT-A imaging using this particular Spectralis® OCT-A prototype and can impact quantitative vascular density metrics. Future studies should review images for artifacts before drawing definitive conclusions.

The role of OCT-A in retinal disease management

Optical coherence tomography angiography (OCT-A) is a non-invasive, non-dye-based imaging modality that has the potential to enhance our understanding of retinal diseases. While this rapidly advancing imaging modality offers great potential, there is a need for community-wide understanding of the range of technologies and methods for interpreting the images, as well as a need to enhance understanding of images from disease-free eyes for reference when screening for retinal diseases. Importantly, clinical trials have been designed without OCT-A-based endpoints; therefore, caution is required when making treatment decisions based on OCT-A imaging alone. With this in mind, a full understanding of the advantages and limitations of OCT-A will be vital for effective development of the technique within the field of ophthalmology. On behalf of the Vision Academy Steering Committee (sponsored by Bayer), this publication summarizes the views of the authors on the current use of OCT-A imaging and explores its potential for future applications in research and clinical practice.

Optical coherence tomography: A guide to interpretation of common macular diseases

Optical coherence tomography is a quick, non invasive and reproducible imaging tool for macular lesions and has become an essential part of retina practice. This review address the common protocols for imaging the macula, basics of image interpretation, features of common macular disorders with clues to differentiate mimickers and an introduction to choroidal imaging. It includes case examples and also a practical algorithm for interpretation.