Spectral-Domain Optical Coherence Tomography Analysis of Fibrotic Lesions in Neovascular Age-Related Macular Degeneration

Predictors of 24-month onset of macular fibrosis in type 3 macular neovascularisation

AIMS

To explore prognostic multimarker models for progression to macular fibrosis (MF) over 24 months specific to type 3 macular neovascularisation (T3 MNV).

METHODS

This retrospective, exploratory, single-centre, cohort study comprised 65 eyes of 43 Caucasian patients with treatment naive T3 MNV, all with a 24-month follow-up post anti-VEGF therapy using a strict pro-re-nata (PRN) regimen. Data on demographic features, clinical findings, frequency of intravitreal treatments and optical coherence tomography biomarkers were collected at baseline and after 12 and 24 months of follow-up. Logistic regression models (LRM) and receiver-operating curve (C-index) analyses were performed to evaluate the prognostic ability of the studied biomarkers in discriminating between MF affected and unaffected patients.

RESULTS

At final follow-up, MF was present in 46.2% of eyes. Subretinal hyper-reflective material (SHRM) and subretinal pigment epithelium multilaminar hyper-reflectivity (multilaminae) emerged as significant predictors for MF, with adjusted odds ratios (OR) of 18.0 (95% CL 13.4 to 24.1) and 11.8 (95% CL 8.66 to 16.0), respectively. Additionally, the presence of multifocal lesions (OR 0.04, 95% CL 0.01 to 0.30) appeared to decrease the likelihood of MF. C-indexes for the selected LRMs ranged between 0.92 and 0.88, indicating a comparably high discriminant ability. Despite consistent treatment schedules between the two groups (MF: median intravitreal treatment (IVT) number=10.5, IQR=7; non-MF: median IVT=10, IQR=6), a decline in best-corrected visual acuity was noted in the group with MF onset over the 24-month follow-up (-13.0 ETDRS letters; 95% CL -22.1 to -3.9; p=0.006).

CONCLUSION

Our study identifies SHRM and multilaminae as relevant predictors of 24-month onset of MF in patients with T3 MNV. These findings enrich our understanding of the development of MF in T3 MNV and can guide improved risk prognostication. Future research should consider larger samples and prospective designs to validate these predictors.

Exploring the role of granzyme B in subretinal fibrosis of age-related macular degeneration

Age-related macular degeneration (AMD), a prevalent and progressive degenerative disease of the macula, is the leading cause of blindness in elderly individuals in developed countries. The advanced stages include neovascular AMD (nAMD), characterized by choroidal neovascularization (CNV), leading to subretinal fibrosis and permanent vision loss. Despite the efficacy of anti-vascular endothelial growth factor (VEGF) therapy in stabilizing or improving vision in nAMD, the development of subretinal fibrosis following CNV remains a significant concern. In this review, we explore multifaceted aspects of subretinal fibrosis in nAMD, focusing on its clinical manifestations, risk factors, and underlying pathophysiology. We also outline the potential sources of myofibroblast precursors and inflammatory mechanisms underlying their recruitment and transdifferentiation. Special attention is given to the potential role of mast cells in CNV and subretinal fibrosis, with a focus on putative mast cell mediators, tryptase and granzyme B. We summarize our findings on the role of GzmB in CNV and speculate how GzmB may be involved in the pathological transition from CNV to subretinal fibrosis in nAMD. Finally, we discuss the advantages and drawbacks of animal models of subretinal fibrosis and pinpoint potential therapeutic targets for subretinal fibrosis.

Distinct Pathways of Macular Atrophy in Type 3 Macular Neovascularization Associated With AMD

Purpose

To explore the occurrence of macular atrophy (MA) in eyes with age-related macular degeneration (AMD)-associated Type 3 macular neovascularization (MNV) treated with anti-vascular endothelial growth factor (anti-VEGF) therapy. Importantly, we aimed at describing the existence of separate pathways leading to MA.

Methods

We analyzed 41 participants (41 eyes) with treatment-naïve Type 3 MNV who were followed up for a duration of 12 months after beginning the anti-VEGF therapy. At the one-year follow-up visit, optical coherence tomography (OCT) scans were reviewed for the presence of MA. MA regions of interest (ROIs) were selected and traced back to their original dominant baseline lesion (i.e., precursor) through previous serially captured OCT scans. Baseline lesions included precursors associated with the development and exudation of MNV and causes external to the neovascularization itself.

Results

At the one-year follow-up visit, MA was graded to be present in 38 (92.7%) out of 41 eyes. These 78 MA ROIs were divided into two subgroups according to the precursor lesion, yielding a group of 53 MA lesions with precursors associated with the development and exudation of MNV (i.e., MA caused by physical harm from Type 3 neovessels, collapse of a serous pigment epithelium detachment, and fibrosis) and 25 MA regions with precursors external to the neovascularization itself (i.e., MA caused by drusen or subretinal drusenoid deposits).

Conclusions

Eyes with Type 3 MNV are commonly complicated by MA and precursors of MA include causes associated with the development and exudation of MNV, as well as lesions unrelated to the neovascularization process itself.

Fibrosis in neovascular age-related macular degeneration: A review of definitions based on clinical imaging

Despite the success of antiangiogenic therapy in controlling exudation in neovascular age-related macular degeneration (nAMD), the involvement of the outer retina in fibrosis results in gradual vision loss over time. The development of drugs that prevent or ameliorate fibrosis in nAMD requires that it is accurately detected and quantified with reliable endpoints and identification of robust biomarkers. Achievement of such an aim is currently challenging due to the lack of a consensus definition of fibrosis in nAMD. As a first step towards the establishment of a clear definition of fibrosis, we provide an extensive overview of the imaging modalities and criteria used to characterize fibrosis in nAMD. We observed variety in the selection of individual and combinations of imaging modalities, and criteria for detection. We also observed heterogeneity in classification systems and severity scales for fibrosis. The most commonly used imaging modalities were color fundus photography, fluorescein angiography and optical coherence tomography (OCT). A multimodal approach was frequently utilized. Our review suggests that OCT offers a more detailed, objective and sensitive characterization than color fundus photography/fluorescein angiography. Thus, we recommend it as a primary modality for fibrosis evaluation. This review provides a basis for future discussions to reach a consensus definition using standardized terms based on a detailed characterization of fibrosis, its presence and evolution, and taking into consideration impact on visual function. Achieving this goal is of paramount importance for the development of antifibrotic therapies.

Ten-Year Incidence of Fibrosis and Risk Factors for Its Development in Neovascular Age-Related Macular Degeneration

PURPOSE

To report the incidence and risk factors for fibrosis at 10 years in a large cohort of persons with neovascular age-related macular degeneration (nAMD).

DESIGN

Retrospective, multicenter, cohort study.

METHODS

We included 225 naive nAMD eyes that underwent intravitreal anti-vascular endothelial growth factor treatment over 10 years of follow-up at two Italian referral centers. Demographic and clinical data were reviewed at baseline and on an annual basis. Onset of fibrosis was defined by clinically assessing photographs, fundus descriptions, or fluorescein angiograms. Optical coherence tomography (OCT) scans of fibrosis were inspected by an external reading center and graded as subretinal pigment epithelium (RPE), mixed, or subretinal.

RESULTS

The mean age at baseline was of 72.1 ± 6.9 years. The incidence rate of fibrosis was estimated to be 8.9 per 100 person-years, with a cumulative incidence of 62.7% at 10 years. Fibrotic lesions were sub-RPE in 46.1%, mixed in 29.8%, and subretinal in 22.7%. Independent factors associated with fibrosis included the following: larger central subfield thickness variation (P < .001), submacular hemorrhages (P = .008), higher number of injections (P = .01), and worse baseline visual acuity (VA) (P = .03). Type 2 macular neovascularization was significantly associated with mixed and subretinal fibrosis. VA significantly declined over 10 years (-16.4 Early Treatment Diabetic Retinopathy Study [ETDRS] letters), particularly in eyes with mixed and subretinal fibrosis (P < .001).

CONCLUSIONS

We identified a 62.7% cumulative incidence of fibrosis in a large nAMD cohort at 10 years. Fibrosis was more common with frequent reactivations and lower baseline VA; its onset had a significant impact on final VA. This supports the hypothesis that nAMD patients should be promptly treated with proactive regimens.

NATURAL COURSE AND CLASSIFICATION OF EXTENSIVE MACULAR ATROPHY WITH PSEUDODRUSEN-LIKE APPEARANCE

PURPOSE

To describe the imaging characteristics and topographic expansion of retinal pigment epithelium (RPE) and outer retinal atrophy in extensive macular atrophy with pseudodrusen-like appearance.

METHODS

Three-year, prospective, observational study. Nine patients with extensive macular atrophy with pseudodrusen-like appearance (17 eyes; 6 women) with no other ocular conditions were annually examined; one eye was excluded because of macular neovascularization. Best-corrected visual acuity measurement, fundus photographs, blue-light autofluorescence, and optical coherence tomography were performed at each visit. Formation of atrophy was analyzed on optical coherence tomography at foveal and extrafoveal areas following the Classification of Atrophy Meeting recommendations. Spatial enlargement throughout four sectors was assessed on blue-light autofluorescence after placing an Early Treatment for Diabetic Retinopathy Study grid centered on the foveola.

RESULTS

Mean age was 53.0 ± 2.1 years at baseline with a follow-up of 36.6 ± 0.7 months. Thinning of the outer nuclear layer and disruption of the ellipsoid zone initially appeared above areas of RPE-Bruch membrane separation and preceded RPE atrophy. Subfoveal fibrosis was seen in 65% of the eyes. Superior sector involvement was found in all patients at baseline and was significantly larger than the other sectors at any time point ( P < 0.001). Best-corrected visual acuity declined from 68.0 ± 15.7 letters to 44.8 ± 14.9 letters during the follow-up and was significantly associated with subfoveal atrophy ( P < 0.001) and fibrosis ( P = 0.02).

CONCLUSION

Our findings suggest that primary alterations in patients with extensive macular atrophy with pseudodrusen-like appearance are present at the outer segment-RPE interface, with the superior Early Treatment for Diabetic Retinopathy Study sector being the most vulnerable, which progresses to extensive atrophy of the RPE and outer retinal layers. Accordingly, we propose a three-stage disease classification.

Review of Fibrosis in Neovascular Age-Related Macular Degeneration

PURPOSE

To report the diagnosis and definitions, epidemiology, risk factors, and visual outcomes of fibrosis in neovascular age-related macular degeneration (nAMD).

DESIGN

Systematic review and meta-analysis.

METHODS

The review was performed using the Cochrane Handbook and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Observational studies and randomized controlled trials were included.

RESULTS

Identification of fibrosis is challenging. Optical coherence tomography angiography and polarization-sensitive optical coherence tomography represent novel options in multimodal imaging. The prevalence of fibrosis at baseline, 12, 24, and 60 months was 13%, 32%, 36%, and 56%, respectively. Approximately 60% of the fibrosis burden in nAMD at 5 years was present in the first year of treatment. Fibrosis development was highest in the first 12 months and slowed down over time. The risk factors of fibrosis included classic choroidal neovascularization (CNV), intra-retinal fluid, hemorrhage, hyperreflective material, CNV lesion size, and retinal thickness. Sub-retinal fluid and pigment epithelial detachment may be protective. Treatment-associated factors included disease activity and time to diagnosis. At baseline, the best corrected visual acuity in eyes with fibrosis was poorer than in eyes without fibrosis (-18.50 letters); this difference became larger at 12 months despite treatment (-26.86 letters).

CONCLUSIONS

There is a need to identify effective treatment strategies for fibrosis and to closely monitor at-risk patients. More studies involving multimodal imaging are required to clarify the definitions and grading criteria for fibrosis.

Pigment epithelial detachment composition indices (PEDCI) in neovascular age-related macular degeneration

We provide an automated analysis of the pigment epithelial detachments (PEDs) in neovascular age-related macular degeneration (nAMD) and estimate areas of serous, neovascular, and fibrous tissues within PEDs. A retrospective analysis of high-definition spectral-domain OCT B-scans from 43 eyes of 37 patients with nAMD with presence of fibrovascular PED was done. PEDs were manually segmented and then filtered using 2D kernels to classify pixels within the PED as serous, neovascular, or fibrous. A set of PED composition indices were calculated on a per-image basis using relative PED area of serous (PEDCI-S), neovascular (PEDCI-N), and fibrous (PEDCI-F) tissue. Accuracy of segmentation and classification within the PED were graded in masked fashion. Mean overall intra-observer repeatability and inter-observer reproducibility were 0.86 ± 0.07 and 0.86 ± 0.03 respectively using intraclass correlations. The mean graded scores were 96.99 ± 8.18, 92.12 ± 7.97, 91.48 ± 8.93, and 92.29 ± 8.97 for segmentation, serous, neovascular, and fibrous respectively. Mean (range) PEDCI-S, PEDCI-N, and PEDCI-F were 0.253 (0-0.952), 0.554 (0-1), and 0.193 (0-0.693). A kernel-based image processing approach demonstrates potential for approximating PED composition. Evaluating follow up changes during nAMD treatment with respect to PEDCI would be useful for further clinical applications.

Short-Term Outcomes After COVID-19-Related Treatment Interruption Among Patients with Neovascular Age-Related Macular Degeneration Receiving Intravitreal Bevacizumab

Purpose

To assess outcomes and recovery strategy of patients undergoing intravitreal injections for exudative age-related macular degeneration who experienced COVID-19 related interruption in treatment during complete lockdown.

Methods

This was a retrospective, observational case study. We used a mixed effect model with random intercepts to evaluate best corrected visual acuity (BCVA) accounting for measured central macular thickness (CMT) and individual variability of each eye. Furthermore, we analysed measures of the pigmented epithelium detachment as well as presence of subretinal fluid and intraretinal cysts.

Results

We included 39 patients and we found a significant reduction in the BCVA between the pre- and post-lockdown controlling for CMT. There was no significant difference in pigmented epithelium detachment and in presence of subretinal fluid and intraretinal cysts.

Conclusion

We detected a significant loss in visual function. The magnitude of the average loss was, however, limited suggesting good efficacy of the recovery strategy.

Prechoroidal cleft thickness correlates with disease activity in neovascular age-related macular degeneration

Purpose

The purpose of this study was to investigate the structural variations of the hyporeflective pocket of fluid (prechoroidal cleft) located between Bruch’s membrane and the hyperreflective material within the pigment epithelial detachment (PED) in patients with neovascular age-related macular degeneration (nAMD).

Methods

In this retrospective, observational case series study, patients diagnosed with nAMD and prechoroidal cleft associated with other activity signs of the macular neovascularization (MNV) were included. Structural optical coherence tomography (OCT) scans were evaluated to obtain anatomical measurements of prechoroidal cleft and PED at three different visits (T0, inactive MNV; T1, active MNV; T2, treated inactive MNV). The variations in size of the cleft and the PED were correlated with nAMD activity.

Results

Twenty-nine eyes from 27 patients were included. The subfoveal measurements showed a significant increase of prechoroidal cleft height and width from T0 to T1 (P < 0.05) and a subsequent decrease of the cleft height after treatment with anti-VEGF agents (P = 0.004). A similar significant trend was observed for the greatest prechoroidal cleft height and width, obtained assessing the whole OCT raster. In the multivariate analysis, the cleft height was significantly affected by both time (P = 0.001) and PED height (P < 0.0001). By contrast, the effect of fibrovascular tissue size within the PED was not significant. Visual acuity did not correlate with prechoroidal cleft size.

Conclusion

Prechoroidal cleft increased in association with MNV reactivation and decreased after treatment. Our results suggest that prechoroidal cleft could represent an accumulation of fluid actively exudating from the MNV and should be considered a sign of nAMD activity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05384-w.

Optical coherence tomography features of the repair tissue following RPE tear and their correlation with visual outcomes

To assess the optical coherence tomography (OCT) features of the repair tissue after retinal pigment epithelial (RPE) tear in neovascular age-related macular degeneration. Retrospective, observational study. Medical and imaging records of patients that developed tears after starting anti-VEGF treatment and with at least 12 months of follow-up were reviewed. OCT reflectivity of the RPE-subretinal hyperreflective tissue (SHT) complex was measured at 6, 12 and 18 months (when available). Reflectivity of the adjacent unaffected RPE-Bruch’s membrane was taken as internal reference. Other variables: grade and rip occurrence (early/late); number of intravitreal injections; type of macular neovascularization; sub-macular hemorrhage (SMH) at onset. Forty-nine eyes (age: 76.1 ± 7.0 years; VA: 0.54 ± 0.27 LogMAR) were included. Thirty-eight eyes had OCT signs of healing during the follow-up, with 21 showing SMH at baseline. Final VA positively correlated with the number of injections and negatively correlated with the RPE-SHT reflectivity and the presence of SMH (p < 0.001). Reflectivity of the RPE-SHT complex was positively associated with time and SMH at baseline (p < 0.05). In our study, most eyes showed signs of tissue repair after RPE tear. The reflectivity of repair tissue, the SMH presence and the number of anti-VEGF injections appeared to be major predictors of visual outcomes.

Morphological features and prognostic significance of multilayered pigment epithelium detachment in age-related macular degeneration

AIMS

To investigate the structure of multilayered pigment epithelial detachment (m-PED) in neovascular age-related macular degeneration, and its association with visual prognosis and the progression of fibrotic scars at 12 months.

METHODS

We retrospectively analysed 68 eyes of 63 patients with m-PED that included a prechoroidal cleft. The compartments within m-PED were divided into neovascular tissue (layer 1), a hyper-reflective band (layer 2), and a prechoroidal cleft (layer 3). Clinical variables were compared between patients manifesting layer 2 and those who did not. Multiple regression analyses were used to find the factors related to visual outcome and fibrotic scar formation.

RESULTS

Layer 2 was detected in 38 (55.9 %) of 68 eyes. With continuous treatment, the group with layer 2 showed gradual visual deterioration (p<0.001 at month 12), while the group without layer 2 showed visual improvement (p<0.001 at month 12). In the group with layer 2, the thickness of layer 2 significantly increased, and in the group without layer 2, if it formed, it increased gradually (p=0.004 at month 12). In both groups, other layers significantly decreased by month 12. The presence of layer 2 at baseline was significantly associated with a poor visual outcome (p=0.009) and fibrotic scar formation (p=0.023).

CONCLUSIONS

The m-PED with layer 2 had a higher risk of fibrotic scar formation and was associated with a poor visual prognosis. Layer 2 may be an early stage precursor of a fibrotic scar.

Multimodal imaging and electroretinography highlights the role of VEGF in the laser-induced subretinal fibrosis of monkey

Age-related macular degeneration (AMD) is a leading cause of blindness. Laser-induced nonhuman primate choroidal neovascularization (CNV) is a widely used animal model of neovascular AMD. Subretinal fibrosis (SFb) is the major limiting factor of effective anti-VEGF therapy for neovascular AMD, yet SFb has never been systematically analyzed in the primate CNV model and if VEGF directly affect SFb is unknown. We recruited a large cohort of rhesus macaques to study the occurrence, multimodal imaging and electroretinography (ERG) features, and related cytokines of SFb. Here we show that among 33 rhesus macaques, 88% CNV eyes developed SFb. Spectral domain optical coherence tomography (SD-OCT) identified four types of subretinal hyper-reflective material (SHRM) of SFb in primate. Multimodal imaging is reliable for monitoring SFb and matches the histological results well. Reduced amplitude of oscillatory potentials correlates with the thinning of inner retina layers and is a possible SFb indicator. Iba1⁺ microglia/macrophage cells infiltrated in the fibrotic lesions, and aqueous cytokine analysis identified four fibrosis-related factors (GM-CSF, IL-10, TGFβ2 and VEGF). Unexpectedly, we found sustained expression of VEGF may be an important inducer of SFb, and anti-VEGF therapy actually partially suppresses SFb. Taken together, our data suggest the laser-induced primate SFb model, coupled with multimodal imaging and ERG recording, is a useful system to dissect the pathogenesis and explore the rationale of treatment for SFb; and combined therapy with anti-VEGF and anti-fibrosis agents is necessary for AMD treatment.

Differential Expression of Kinin Receptors in Human Wet and Dry Age-Related Macular Degeneration Retinae

Kinins are vasoactive peptides and mediators of inflammation, which signal through two G protein-coupled receptors, B1 and B2 receptors (B1R, B2R). Recent pre-clinical findings suggest a primary role for B1R in a rat model of wet age-related macular degeneration (AMD). The aim of the present study was to investigate whether kinin receptors are differentially expressed in human wet and dry AMD retinae. The cellular distribution of B1R and B2R was examined by immunofluorescence and in situ hybridization in post-mortem human AMD retinae. The association of B1R with inflammatory proteins (inducible nitric oxide synthase (iNOS) and vascular endothelial growth factor A (VEGFA)), fibrosis markers and glial cells was also studied. While B2R mRNA and protein expression was not affected by AMD, a significant increase of B1R mRNA and immunoreactivity was measured in wet AMD retinae when compared to control and dry AMD retinae. B1R was expressed by Müller cells, astrocytes, microglia and endothelial/vascular smooth muscle cells, and colocalized with iNOS and fibrosis markers, but not with VEGFA. In conclusion, the induction and upregulation of the pro-inflammatory and pro-fibrotic kinin B1R in human wet AMD retinae support previous pre-clinical studies and provide a clinical proof-of-concept that B1R represents an attractive therapeutic target worth exploring in this retinal disease.