Development and Course of Scars in the Comparison of Age-Related Macular Degeneration Treatments Trials

Subretinal fibrosis secondary to neovascular age-related macular degeneration: mechanisms and potential therapeutic targets

Subretinal fibrosis is the end-stage sequelae of neovascular age-related macular degeneration. It causes local damage to photoreceptors, retinal pigment epithelium, and choroidal vessels, which leads to permanent central vision loss of patients with neovascular age-related macular degeneration. The pathogenesis of subretinal fibrosis is complex, and the underlying mechanisms are largely unknown. Therefore, there are no effective treatment options. A thorough understanding of the pathogenesis of subretinal fibrosis and its related mechanisms is important to elucidate its complications and explore potential treatments. The current article reviews several aspects of subretinal fibrosis, including the current understanding on the relationship between neovascular age-related macular degeneration and subretinal fibrosis; multimodal imaging techniques for subretinal fibrosis; animal models for studying subretinal fibrosis; cellular and non-cellular constituents of subretinal fibrosis; pathophysiological mechanisms involved in subretinal fibrosis, such as aging, infiltration of macrophages, different sources of mesenchymal transition to myofibroblast, and activation of complement system and immune cells; and several key molecules and signaling pathways participating in the pathogenesis of subretinal fibrosis, such as vascular endothelial growth factor, connective tissue growth factor, fibroblast growth factor 2, platelet-derived growth factor and platelet-derived growth factor receptor-β, transforming growth factor-β signaling pathway, Wnt signaling pathway, and the axis of heat shock protein 70-Toll-like receptors 2/4-interleukin-10. This review will improve the understanding of the pathogenesis of subretinal fibrosis, allow the discovery of molecular targets, and explore potential treatments for the management of subretinal fibrosis.

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.

Aqueous humor cytokine levels in patients with subretinal fibrosis in neovascular age-related macular degeneration

PURPOSE

To investigate aqueous humor cytokine levels in neovascular age-related macular degeneration (nAMD) patients with subretinal fibrosis and to explore the relationship between cytokine levels and disease severity.

METHODS

The aqueous humor samples were collected from 16 eyes with subretinal fibrosis due to nAMD (SRFi group), 33 eyes with nAMD without subretinal fibrosis (nAMD group) and 28 eyes with cataract patients (control group). Clinical samples were analyzed for 5 cytokines,including vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), basic fibroblast growth factor (bFGF), transforming growth factor-α (TGF-α), platelet-derived growth factor-BB (PDGF-BB).

RESULTS

Aqueous humor cytokines VEGF and bFGF were significantly higher in nAMD patients than controls (all P < 0.05), and VEGF, bFGF and TGF-α levels were significantly higher in SRFi patients than controls (all P < 0.05). No significant differences in 4 cytokine levels were observed between nAMD and SRFi patients in aqueous humor. We also identified a positive correlation between the aqueous humor levels of IL-6 and VEGF in the SRFi group, while bFGF and TGF-α in the nAMD group. Moreover, VEGF levels were strongly related to BCVA, and bFGF levels were positively related to the maximum thickness of subretinal hyperreflective material (SHRM) in fibrosis due to nAMD.

CONCLUSION

VEGF and bFGF levels in aqueous humor were elevated in macular neovascularization with and without subretinal fibrosis. TGF-α levels exclusively differed in neovascular AMD with fibrosis. Cytokines are distributed differently and play a synergistic role in different stages (angiogenesis and fibrogenesis) of nAMD. The bFGF levels could predict the negative prognosis in fibrosis due to nAMD.

Effect of baseline fluid localization on visual acuity and prognosis in type 1 macular neovascularization treated with anti-VEGF

PURPOSE

To assess the prognostic value of subretinal (SRF) and intraretinal fluid (IRF) localizations in type 1 macular neovascularization (MNV) due to age-related macular degeneration (AMD).

SUBJECTS

Eyes were prospectively treated with anti-vascular epithelial growth factor (anti-VEGF) intravitreal injections (IVT) according to a Pro-Re-Nata (PRN) or Treat and Extend (TAE) regimen during 24 months. A total of 211 eyes with treatment-naïve type 1 MNV secondary to AMD were consecutively included. Eyes were divided between 2 groups according to the fluid localization: presence of SRF alone (SRF group), or presence of IRF associated or not with SRF (IRF ± SRF group).

RESULTS

At baseline the mean BCVA was 66.2 letters. SRF was present in 94.8% of eyes, IRF in 30.8%, and both in 25.6%. Data were available for 201 eyes at 12 months, and 157 eyes at 24 months. The presence of IRF at baseline was associated with lower baseline BCVA and significantly lower BCVA at 12 months (p < 0.001) and 24 months (p < 0.001). Eyes with SRF alone displayed better visual outcomes (BCVA at month 12, SRF = 74.3 letters, IRF ± SRF = 56.9 letters). In the presence of baseline IRF, fibrosis (p = 0.03) and atrophy (p < 0.001) were more frequently found at 24 months. In a multivariate model, the presence of baseline IRF was significantly associated with lower BCVA at month 12 but not at month 24.

CONCLUSION

In type 1 MNV, the presence of baseline IRF was associated with worse visual outcomes compared to SRF alone, and more frequent atrophy and fibrosis.

Approved AI-based fluid monitoring to identify morphological and functional treatment outcomes in neovascular age-related macular degeneration in real-world routine

AIM

To predict antivascular endothelial growth factor (VEGF) treatment requirements, visual acuity and morphological outcomes in neovascular age-related macular degeneration (nAMD) using fluid quantification by artificial intelligence (AI) in a real-world cohort.

METHODS

Spectral-domain optical coherence tomography data of 158 treatment-naïve patients with nAMD from the Fight Retinal Blindness! registry in Zurich were processed at baseline, and after initial treatment using intravitreal anti-VEGF to predict subsequent 1-year and 4-year outcomes. Intraretinal and subretinal fluid and pigment epithelial detachment volumes were segmented using a deep learning algorithm (Vienna Fluid Monitor, RetInSight, Vienna, Austria). A predictive machine learning model for future treatment requirements and morphological outcomes was built using the computed set of quantitative features.

RESULTS

Two hundred and two eyes from 158 patients were evaluated. 107 eyes had a lower median (≤7) and 95 eyes had an upper median (≥8) number of injections in the first year, with a mean accuracy of prediction of 0.77 (95% CI 0.71 to 0.83) area under the curve (AUC). Best-corrected visual acuity at baseline was the most relevant predictive factor determining final visual outcomes after 1 year. Over 4 years, half of the eyes had progressed to macular atrophy (MA) with the model being able to distinguish MA from non-MA eyes with a mean AUC of 0.70 (95% CI 0.61 to 0.79). Prediction for subretinal fibrosis reached an AUC of 0.74 (95% CI 0.63 to 0.81).

CONCLUSIONS

The regulatory approved AI-based fluid monitoring allows clinicians to use automated algorithms in prospectively guided patient treatment in AMD. Furthermore, retinal fluid localisation and quantification can predict long-term morphological outcomes.

The complement pathway as a therapeutic target for neovascular age-related macular degeneration-mediated subretinal fibrosis

Neovascular age-related macular degeneration (nAMD) is the leading cause of blindness in the elderly in developed countries. Intravitreal injection of VEGF inhibitors is the mainstream therapy for nAMD, although nearly 50% of the patients do not respond or respond poorly to the therapy. One of the main reasons for the poor outcome of the therapy is the development of subretinal macular fibrosis, a process of excessive deposition of extracellular matrix proteins around the diseased blood vessels. Currently, there is no medication to prevent or treat the condition. Here, we discussed recent advances in the pathogenesis of nAMD-mediated macular fibrosis, with a focus on the role of the complement system. We further proposed approaches to target the complement system for the management of macular fibrosis and highlighted the area of further research for future clinical applications of complement-based therapy.

Comparative study on the efficacy of Conbercept and Aflibercept in the treatment of neovascular age-related macular degeneration

This study compares the effectiveness of Conbercept and Aflibercept in treating neovascular age-related macular degeneration (nAMD). Conducted at the First Affiliated Hospital of Chongqing Medical University's Ophthalmology Department (May 2020-May 2023), this prospective study enrolled 159 nAMD patients. Participants were randomly divided into two groups: one receiving 0.5 mg Conbercept and the other 2 mg Aflibercept intravitreal injections. Over 12 months, the study, employing a Treat-and-Extend (T&E) regimen, assessed Best-Corrected Visual Acuity (BCVA), Central Retinal Thickness (CRT) changes and injection frequency. Of the 159 patients, 137 (149 eyes) completed the study. No significant age difference was found between the groups (P = 0.331). After 12 months, BCVA improved similarly in both groups (Conbercept: 52.8 ± 18.9, Aflibercept: 52.0 ± 19.7 letters; P = 0.820). CRT reduction was also comparable (Conbercept: 246.3 ± 82.8 µm, Aflibercept: 275.9 ± 114.3 µm; P = 0.079). Injection frequencies averaged 6.9 ± 0.7 (Conbercept) and 6.7 ± 0.7 (Aflibercept; P = 0.255). Subtype analysis revealed Type 1 MNV had higher baseline BCVA and lower CRT, with more frequent injections compared to other types. Both Conbercept and Aflibercept are clinically similar in efficacy for nAMD, with the T&E regimen proving therapeutically effective and potentially reducing patient costs. Anti-VEGF treatment efficacy varies across nAMD subtypes, indicating a potential benefit in tailored treatments for specific subtypes.Clinical trial registration number NCT05539235 (Protocol Registration and Results System).

Influence of submacular hemorrhage at baseline on the long-term outcomes of aflibercept treatment for typical neovascular age-related macular degeneration and polypoidal choroidal vasculopathy

PURPOSE

To investigate the influence of submacular hemorrhage (SMH) at baseline on long-term visual outcomes of patients with typical age-related macular degeneration (tAMD) and polypoidal choroidal vasculopathy (PCV) treated with intravitreal aflibercept (IVA).

METHODS

In this retrospective study, eyes of treatment-naïve patients with tAMD and PCV who initiated IVA under a treat-and-extend regimen and were followed up for ≥ 5 years were classified into the tAMD-SMH ( +), tAMD-SMH (-), PCV-SMH ( +), and PCV-SMH (-) groups based on the presence of SMH at baseline. Best-corrected visual acuity (BCVA) changes and macular fibrosis and atrophy incidences were assessed.

RESULTS

This study included 127 eyes (127 patients), including 51 with tAMD and 76 with PCV; 18 eyes had SMH at baseline. In the tAMD-SMH ( +) group (n = 6), the mean logMAR BCVA significantly deteriorated from 0.59 ± 0.45 at baseline to 0.88 ± 0.47 at the final visit (P = 0.024). No significant BCVA changes were observed in the tAMD-SMH (-) (n = 45), PCV-SMH ( +) (n = 12), or PCV-SMH (-) (n = 64) groups (all P > 0.05). The tAMD-SMH ( +) group showed a significantly higher incidence of macular fibrosis at the final visit than did the tAMD-SMH (-) group (P = 0.042). There was no influence of baseline SMH on the macular fibrosis incidence in eyes with PCV and the macular atrophy incidence in eyes with tAMD and PCV.

CONCLUSION

The presence of SMH at baseline resulted in poorer long-term visual acuity in eyes with tAMD, even with aflibercept treatment. However, no such influence was observed in eyes with PCV.

Macular Neovascularization Type Influence on Anti-VEGF Intravitreal Therapy Outcomes in Age-Related Macular Degeneration

PURPOSE

To evaluate the influence of macular neovascularization (MNV) lesion type on 12-month clinical outcomes in treatment-naive eyes with neovascular age-related macular degeneration (nAMD) treated with anti-VEGF drugs nationwide.

DESIGN

Multicenter national nAMD database observational study.

SUBJECTS

One thousand six hundred six treatment-naive nAMD eyes (1330 patients) undergoing anti-VEGF therapy for 12 months nationwide.

METHODS

Demographics, visual acuity (VA) in logarithm of the minimum angle of resolution letters, number of injections and visits were was collected using a validated web-based tool. Neovascular lesion phenotype was classified as type 1 (T1, n = 711), type 2 (T2, n = 505), type 3 (T3, n = 315), and aneurysmal type 1 (A-T1, n = 75), according to the new proposed consensus classification.

MAIN OUTCOME MEASURES

Mean VA change at 12 months, final VA at 12 months, number of injections, time to lesion inactivation.

RESULTS

A total of 1606 treatment-naive nAMD eyes (1330 patients) received a median of 7 injections over 12 months. Mean (± standard deviation) baseline VA was significantly lower for T2 (49.4 ± 23.5 letters) compared with T1 (57.8 ± 20.8) and T3 (58.2 ± 19.4) (both P < 0.05) lesions. Mean VA change at 12 months was significantly greater for A-T1 (+9.5 letters) compared with T3 (+3.1 letters, P < 0.05). Patients with T3 lesions had fewer active visits (24.9%) than those with other lesion types (T1, 30.5%; T2, 32.6%; A-T1, 27.5%; all P < 0.05). Aflibercept was the most used drug in A-T1 lesions (70.1%) and ranibizumab in T1 (40.7%), T2 (57.7%), and T3 (47.6%) lesions.

CONCLUSIONS

This study highlights the relevance of MNV type on clinical outcomes in nAMD and reports significant differences in baseline VA, VA change, and lesion activity at 12 months. This report provides data about lesion-specific clinical features, which may guide the management of nAMD cases and potentially support personalized clinical decision making for these patients.

FINANCIAL DISCLOSURE(S)

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

Prevalence and Risk Factors of Age-Related Macular Degeneration in South Korea: Korea National Health and Nutrition Examination Survey

PURPOSE

To evaluate the prevalence and risk factors of age-related macular degeneration (AMD) in the Korean population.

METHODS

In this cross-sectional study based on the Korea National Health and Nutrition Examination Survey (2017-2020) data 13,737 participants aged ≥ 40 years with assessable fundus images were included. The prevalence and risk factors of AMD were evaluated. The prevalence of early AMD, geographic atrophy (GA), and neovascular AMD were also assessed. Logistic regression analyses were used to identify risk factors.

RESULTS

The prevalence (95% confidence interval [CI]) of AMD was 13.94% (13.15-14.72). The prevalence (95% CI) of early AMD, GA, and neovascular AMD was 13.07% (12.29-13.85), 0.26% (0.17-0.35), and 0.61% (0.47-0.75), respectively. The prevalence increased with age; it was 3.61%, 11.33%, 20.31%, 31.37%, and 33.98% in participants in their 40s, 50s, 60s, 70s, and ≥ 80 years, respectively. In multivariate analysis, AMD was positively associated with older age (p < 0.001; odds ratio [OR], 1.08; 95% CI, 1.07-1.09), male sex (p = 0.014; OR, 1.27; 95% CI, 1.05-1.53), and lower degree of education (p < 0.001; OR, 1.36 (for junior high school graduates); 95% CI, 1.12-1.65).

CONCLUSIONS

AMD was detected in approximately one-third of individuals aged ≥ 70 years, thus indicating that AMD is a common disease among older Koreans. Regular fundus examinations in populations with risk factors for AMD as well as education on methods to prevent or delay AMD progression, such as the Mediterranean diet, are necessary.

The contribution of pattern recognition receptor signalling in the development of age related macular degeneration: the role of toll-like-receptors and the NLRP3-inflammasome

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss, characterised by the dysfunction and death of the photoreceptors and retinal pigment epithelium (RPE). Innate immune cell activation and accompanying para-inflammation have been suggested to contribute to the pathogenesis of AMD, although the exact mechanism(s) and signalling pathways remain elusive. Pattern recognition receptors (PRRs) are essential activators of the innate immune system and drivers of para-inflammation. Of these PRRs, the two most prominent are (1) Toll-like receptors (TLR) and (2) NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3)-inflammasome have been found to modulate the progression of AMD. Mutations in TLR2 have been found to be associated with an increased risk of developing AMD. In animal models of AMD, inhibition of TLR and NLRP3 has been shown to reduce RPE cell death, inflammation and angiogenesis signalling, offering potential novel treatments for advanced AMD. Here, we examine the evidence for PRRs, TLRs2/3/4, and NLRP3-inflammasome pathways in macular degeneration pathogenesis.

Structure-Function Correlation of Retinal Fibrosis in Eyes with Neovascular Age-Related Macular Degeneration

Purpose: To assess retinal function in areas of presumed fibrosis due to neovascular age-related macular degeneration (nAMD), using multimodal imaging and structure-function correlation. Design: Cross-sectional observational study. Methods: 30 eyes of 30 consecutive patients with nAMD with a minimum history of one year of anti-vascular endothelial growth factor therapy were included. Each patient underwent microperimetry (MP), color fundus photography (CFP), standard spectral-domain-based OCT (SD-OCT), and polarization sensitive-OCT (PS-OCT) imaging. PS-OCT technology can depict retinal fibrosis based on its birefringence. CFP, SD-OCT, and PS-OCT were evaluated independently for the presence of fibrosis at the corresponding MP stimuli locations. MP results and morphologic findings in CFP, SD-OCT, and PS-OCT were co-registered and analyzed using mixed linear models. Results: In total, 1350 MP locations were evaluated to assess the functional impact of fibrosis according to a standardized protocol. The estimated means of retinal areas with signs of fibrosis were 12.60 db (95% confidence interval: 10.44-14.76) in CFP, 11.60 db (95% COI: 8.84-14.36) in OCT, and 11.02 db (95% COI 8.10-13.94) in PS-OCT. Areas evaluated as subretinal fibrosis in three (7.2 db) or two (10.1 db) modalities were significantly correlated with a lower retinal sensitivity than a subretinal fibrosis observed in only one (15.3 db) or none (23.3 db) modality (p < 0.001). Conclusions: CFP, SD-OCT and PS-OCT are all suited to detect areas of reduced retinal sensitivity related to fibrosis, however, a multimodal imaging approach provides higher accuracy in the identification of areas with low sensitivity in MP (i.e., impaired retinal function), and thereby improves the detection rate of subretinal fibrosis in nAMD.

Effects of autophagy inhibitor 3-methyladenine on a diabetic mice model

AIM

To investigate the role of autophagy inhibitor 3-methyladenine (3-MA) on a diabetic mice model (DM) and the potential mechanism.

METHODS

Male C57BL/6J mice were randomly divided into a normal control group (NC group) and an DM group. DM were induced by multiple low-dose intraperitoneal injection of streptozotocin (STZ) 60 mg/kg·d for 5 consecutive days. DM mice were randomly subdivided into untreated group (DM group), 3-MA (10 mg/kg·d by gavage) treated group (DM+3-MA group) and chloroquine (CQ; 50 mg/kg by intraperitoneal injection) treated group (DM+CQ group). The fasting blood glucose (FBG) levels were recorded every week. At the end of experiment, retinal samples were collected. The expression levels of pro-apoptotic proteins cleaved caspase-3, cleaved poly ADP-ribose polymerase 1 (PARP1) and Bax, anti-apoptotic protein Bcl-2, fibrosis-associated proteins Fibronectin and type 1 collagen α1 chain (COL1A1), vascular endothelial growth factor (VEGF), inflammatory factors interleukin (IL)-1β and tumor necrosis factor (TNF)-α, as well as autophagy related proteins LC3, Beclin-1 and P62 were determined by Western blotting. The oxidative stress indicators 8-hydroxydeoxyguanosine (8-OHdG) and malondialdehyde (MDA) were detected by commercial kits.

RESULTS

Both 3-MA and CQ had short-term hypoglycemic effect on FBG and reduced the expression of VEGF and inflammatory factors IL-1β and TNF-α in DM mice. 3-MA also significantly alleviated oxidative stress indicators 8-OHdG and MDA, decreased the expression of fibrosis-related proteins Fibronectin and COL1A1, pro-apoptotic proteins cleaved caspase-3, cleaved PARP1, as well as the ratio of Bax/Bcl-2. CQ had no significant impact on the oxidative stress indicators, fibrosis, and apoptosis related proteins. The results of Western blotting for autophagy related proteins showed that the ratio of LC3 II/LC3 I and the expression of Beclin-1 in the retina of DM mice were decreased by 3-MA treatment, and the expression of P62 was further increased by CQ treatment.

CONCLUSION

3-MA has anti-apoptotic and anti-fibrotic effects on the retina of DM mice, and can attenuate retinal oxidative stress, VEGF expression and the production of inflammatory factors in the retina of DM mice. The underlying mechanism of the above effects of 3-MA may be related to its inhibition of early autophagy and hypoglycemic effect.

Neovascular Progression and Retinal Dysfunction in the Laser-Induced Choroidal Neovascularization Mouse Model

The mouse model of laser-induced choroidal neovascularization (LI-CNV) has been widely used to study neovascular age-related macular degeneration; however, it still lacks a comprehensive characterization. Here, CNV was induced in the eyes of 12-week-old C57BL/6J male mice by argon laser irradiation. We studied the CNV lesion progression of an LI-CNV mouse cohort by using multimodal imaging (color fundus, optical coherence tomography (OCT), and fluorescence angiography, focal electroretinography features for 14 days, and related cytokines, angiogenic factors, and reactive gliosis for 5 days. CNV lesions involving the rupture of the Bruch's membrane were confirmed using funduscopy and OCT after laser photocoagulation. During the initial stage, from the CNV induction until day 7, CNV lesions presented leakage observed by using fluorescence angiography and a typical hyperreflective area with cell infiltration, subretinal leakage, and degeneration of photoreceptors observed through OCT. This correlated with decreased retinal responses to light. Moreover, inflammatory and angiogenic markers were reduced to basal levels in the first 5 days of CNV progression. In contrast, reactive gliosis and the VEGF expression in retinal sections were sustained, with infiltration of endothelial cells in the subretinal space. In the second stage, between days 7 and 14 post-induction, we observed stabilization of the CNV lesions, a hyperfluorescent area corresponding to the formation of fibrosis, and a partial rescue of retinal function. These findings suggest that the LI-CNV lesion development goes through an acute phase during the first seven days following induction, and then the CNV lesion stabilizes. According to these results, this model is suitable for screening anti-inflammatory and anti-angiogenic drugs in the early stages of LI-CNV. At the same time, it is more convenient for screening anti-fibrotic compounds in the later stages.

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.

Old age promotes retinal fibrosis in choroidal neovascularization through circulating fibrocytes and profibrotic macrophages

BACKGROUND

Retinal fibrosis affects 40-70% of neovascular age-related macular degeneration patients. This study investigated the effect of ageing on subretinal fibrosis secondary to choroidal neovascularization and the mechanism of action.

METHODS

Subretinal fibrosis was induced in young (2.5-month) and aged (15-16-month) C57BL/6J mice using the two-stage laser protocol. Five and 30 days later, eyes were collected and stained for CD45 and collagen-1 and observed by confocal microscopy. Fibrocytes (CD45+collagen-1+) were detected in the bone marrow (BM), blood and fibrotic lesions by flow cytometry and confocal microscopy, respectively. BM-derived macrophages (BMDMs) were cultured from young and aged mice with or without TGF-β1 (10 ng/mL) treatment. The expression of mesenchymal marker αSMA (Acta2), fibronectin (Fn1) and collagen-1 (Col1a1) was examined by qPCR and immunocytochemistry, whereas cytokine/chemokine production was measured using the Luminex multiplex cytokine assay. BM were transplanted from 22-month (Ly5.2) aged mice into 2.5-month (Ly5.1) young mice and vice versa. Six weeks later, subretinal fibrosis was induced in recipient mice and eyes were collected for evaluation of fibrotic lesion size.

RESULTS

Under normal conditions, the number of circulating fibrocytes (CD45+collagen-1+) and the expression levels of Tgfb1, Col1a1, Acta2 and Fn1 in BMDMs were significantly higher in aged mice compared to young mice. Induction of subretinal fibrosis significantly increased the number of circulating fibrocytes, enhanced the expression of Col1a1, Acta2 and Fn1 and the production of soluble urokinase plasminogen activator surface receptor (suPAR) but decreased the production of CXCL10 in BMDMs. BMDMs from aged subretinal fibrosis mice produced significantly higher levels of VEGF, angiopoietin-2 and osteopontin than cells from young subretinal fibrosis mice. The subretinal fibrotic lesion in 15-16-month aged mice was 62% larger than that in 2.5-month young mice. The lesion in aged mice contained a significantly higher number of fibrocytes compared to that in young mice. The number of circulating fibrocytes positively correlated with the size of subretinal fibrotic lesion. Transplantation of BM from aged mice significantly increased subretinal fibrosis in young mice.

CONCLUSIONS

A retina-BM-blood-retina pathway of fibrocyte/macrophage recruitment exists during retinal injury. Ageing promotes subretinal fibrosis through higher numbers of circulating fibrocytes and profibrotic potential of BM-derived macrophages.

Efficacy and safety of Aflibercept for the treatment of inflammatory choroidal neovascularization: The ALINEA study

PURPOSE

To evaluate mean change in best-corrected visual acuity (BCVA) at 52 weeks in patients with inflammatory choroidal neovascularization (CNV) treated with aflibercept.

METHODS

We conducted a prospective non-comparative open-label trial. Following one mandatory intravitreal injection of aflibercept, patients were treated under a pro re nata (PRN) dosing regimen with monthly visits.

RESULTS

A total of 19 patients were included, but one presented exclusion criteria; 16 patients were followed for the whole 52-week study, and data for the primary endpoint analysis were available for 14. At baseline, mean BCVA and mean central retinal thickness (CRT) were 64.53 (±19.64) letters and 351.79 (±97.77) μm, respectively. At 52 weeks, the mean change in BCVA was +9.50 (±12.90) letters [95%CI = +2.05-+16.95]. One patient had lost more than 15-letters at 24 weeks, and another one at 52 weeks. CRT change was -62.77 (±100.73) μm at 24 weeks and -66.53 (±97.47) μm at 52 weeks. There was a mean number of 3.56 (±3.29) intravitreal injections at 52 weeks (min = 1; max = 12). No serious ocular adverse events related to the treatment were reported.

CONCLUSIONS

Our study shows that aflibercept is clinically effective, both anatomically and functionally in the treatment of inflammatory CNV. Following the first injection, the PRN strategy appears sufficient for treating most choroidal neovessels.

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.

Efficacy of Aflibercept as initial treatment for neovascular age-related macular degeneration in an Iraqi patient sample

Age-related macular degeneration (AMD) is a progressive degenerative eye disorder that primarily affects individuals over 50. It causes gradual loss of central vision and can lead to irreversible severe visual loss if left untreated. AMD is a leading cause of blindness in the developed world. This study aimed to investigate the effects of a loading dosage of intravitreal Aflibercept on functional and morphological responses in neovascular AMD, considering demographic characteristics and the link between AMD-related retinal symptoms at presentations. A prospective interventional study was conducted from November 2021 to September 2022 on a sample of Iraqi patients with neovascular AMD who had active choroidal neovascularization (CNV) lesions confirmed by OCT-A and received intravitreal Aflibercept 2mg injection as initial therapy (3 loading doses). Best-corrected visual acuity (BCVA) was used to measure functional responses, and central macular thickness (CMT) and maximum area of the retinal thickness (MART) (by SD-OCT) were used to measure morphological responses. The study included 48 patients (57 eyes) with active neovascular AMD. The mean difference of BCVA in log MAR (0.2 ± 0.7) significantly improved from 1.3±0.7 at baseline to 1.1±0.8 after loading Aflibercept (P=0.034). The mean difference in CMT 113.6 ± 125.9 was statistically significant (P<0.0001). Also, the mean change in MART significantly decreased from 444.2 ± 127.1 µm at baseline to 348.7±74.5 µm (p < 0.0001) after loading Aflibercept. This study demonstrated that Aflibercept is a functionally and anatomically successful treatment for neovascular AMD.

Prediction of the short-term efficacy of anti-VEGF therapy for neovascular age-related macular degeneration using optical coherence tomography angiography

Background

To evaluate whether the specific choroidal neovascularization (CNV) characteristics measured using optical coherence tomography angiography (OCTA) can predict the 6-month prognosis of neovascular age-related macular degeneration (nAMD) after anti-vascular endothelial growth factor (anti-VEGF) therapy.

Methods

Patients with type 1, type 2, or mixed-type neovascularization (NV) were prospectively included. Participants underwent an initial loading phase of three consecutive monthly intravitreal injections of Conbercept (0.5 mg) and were switched to a pro re nata (PRN) treatment strategy. OCTA images were evaluated for eyes that underwent follow-up assessments for more than 6 months. CNV lesions were manually segmented, and the CNV area, vessel area, greatest vascular caliber (GVC), and greatest linear dimension (GLD) were compared between responders and non-responders. Two masked graders independently measured the above-mentioned parameters using OCTA, and consistency was assessed using the intraclass correlation coefficient (ICC) values. Multiple logistic regression analysis was performed to evaluate the effect of a 3-month change in the CNV area, GLD, and GVC on the 6-month response to anti-VEGF agents.

Results

Among the 60 eyes of 60 patients with nAMD, 39 were responders and 21 were non-responders. The proportion of CNV types was significantly different between responders and non-responders (P = 0.009). Patients with type 2 or mixed NV seemed more likely to respond to the treatment (28.2% vs. 0.0%, and 30.8% vs. 23.8%, respectively). The change in GVC showed a significant difference between responders (− 4.98 ± 17.17 μm) and non-responders (11.01 ± 14.10 μm) after three monthly intravitreal anti-VEGF injections. Multiple logistic regression analysis showed that only the change in GVC remained significant after controlling for baseline GVC, injection number, and CNV type (adjusted OR = 1.083; P = 0.008).

Conclusions

Type 2 and mixed-type NV were significantly associated with a better response to anti-VEGF therapy. Changes in GVC after 3 months of treatment were significantly associated with a response to anti-VEGF therapy at 6 months.

Characterisation of macular neovascularisation subtypes in age-related macular degeneration to optimise treatment outcomes

The aim of this review is to identify the common characteristics and prognoses of different subtypes of neovascular age-related macular degeneration (nAMD). We also propose recommendations on how to tailor treatments to the subtype of neovessels to optimise patient outcomes. The authors, selected members of the Vision Academy, met to discuss treatment outcomes in nAMD according to macular neovascularisation (MNV) subtypes, using evidence from a literature search conducted on the PubMed database (cut-off date: March 2019). This review article summarises the recommendations of the Vision Academy on how the characterisation of MNV subtypes can optimise treatment outcomes in nAMD. The identification of MNV subtypes has been facilitated by the advent of multimodal imaging. Findings from fluorescein angiography, indocyanine green angiography and spectral-domain optical coherence tomography collectively help refine and standardise the determination of the MNV subtype. To date, three subtypes have been described in the literature and have specific characteristics, as identified by imaging. Type 1 MNV is associated with better long-term outcomes but usually requires more intense anti-vascular endothelial growth factor dosing. Type 2 MNV typically responds quickly to treatment but is more prone to the development of fibrotic scars, which may be associated with poorer outcomes. Type 3 MNV tends to be highly sensitive to anti-vascular endothelial growth factor treatment but may be associated with a higher incidence of outer retinal atrophy, compared with other subtypes. Accurately assessing the MNV subtype provides information on prognosis and helps to optimise the management of patients with nAMD.

Long-term Retinal Morphology and Functional Associations in Treated Neovascular Age-Related Macular Degeneration: Findings from the Inhibition of VEGF in Age-Related Choroidal Neovascularisation Trial

PURPOSE

To describe the frequency of long-term morphologic features and their relationships with visual function in participants who exited the Inhibition of VEGF in Age-Related Choroidal Neovascularisation (IVAN; ISRCTN92166560) trial.

DESIGN

Multicenter cohort study up to 7 years after enrollment.

PARTICIPANTS

Patients enrolled in the IVAN trial, excluding participants who died or withdrew during the trial.

METHODS

Multimodal fundus images, best-corrected visual acuity (BCVA), and low-luminance visual acuity (LLVA) were obtained for a subset of 199 participants who attended a research visit. Clinical sites (n = 20) also provided all visual acuity and clinical information from usual care records for 532 participants and submitted the most recent color, OCT, and other fundus images for 468 participants to a reading center.

MAIN OUTCOME MEASURES

Assessed the following from the most recent images: intralesional macular atrophy (ILMA) within the footprint of the neovascular lesion; hyperreflective material (HRM); intraretinal fluid (IRF); subretinal fluid (SRF); pigment epithelial detachment (PED); and disorganized retinal outer layers (DROLs). Cross-sectional relationships between morphologic features and BCVA/LLVA were estimated.

RESULTS

Intralesional macular atrophy was present in 31.8% of the study eyes at IVAN exit (mean follow-up, 1.96 years) and 89.5% at the most recent imaging visit (mean follow-up, 6.18 years). Hyperreflective material, IRF, SRF, PED, and DROLs were present in 78.8%, 47.7%, 7.6%, 94.5%, and 55% of the study eyes, respectively. In the subset with complete imaging data, in eyes without DROL, the BCVA was worst in the thinnest outer fovea tertile (thinnest minus middle and thickest tertiles, -19.7 and -19.5 letters, respectively), whereas in eyes with DROL, the BCVA was worst in the thickest (thinnest and middle tertiles minus thickest, 12.5 and 12.2, respectively). Regression models showed that the presence of ILMA and HRM was independently associated with BCVA (22 letters worse [95% confidence interval {CI}, -11.2 to -32.8; P < 0.001] and 9.8 letters worse [95% CI, -0.1 to -19.4; P = 0.047], respectively). Subretinal fluid and foveal PED were associated with better BCVA (5.9 letters [95% CI, -7.9 to 19.7; P = 0.399] and 6.4 letters [95% CI, -1.1 to 14.0; P = 0.094], respectively). The model with LLVA was similar. A sensitivity analysis involving the entire eligible cohort yielded similar estimates.

CONCLUSIONS

Macular atrophy and HRM were common after 7 years of follow-up and strongly associated with visual outcomes.

Harnessing the Neuroprotective Behaviors of Müller Glia for Retinal Repair

Progressive and irreversible vision loss in mature and aging adults creates a health and economic burden, worldwide. Despite the advancements of many contemporary therapies to restore vision, few approaches have considered the innate benefits of gliosis, the endogenous processes of retinal repair that precede vision loss. Retinal gliosis is fundamentally driven by Müller glia (MG) and is characterized by three primary cellular mechanisms: hypertrophy, proliferation, and migration. In early stages of gliosis, these processes have neuroprotective potential to halt the progression of disease and encourage synaptic activity among neurons. Later stages, however, can lead to glial scarring, which is a hallmark of disease progression and blindness. As a result, the neuroprotective abilities of MG have remained incompletely explored and poorly integrated into current treatment regimens. Bioengineering studies of the intrinsic behaviors of MG hold promise to exploit glial reparative ability, while repressing neuro-disruptive MG responses. In particular, recent in vitro systems have become primary models to analyze individual gliotic processes and provide a stepping stone for in vivo strategies. This review highlights recent studies of MG gliosis seeking to harness MG neuroprotective ability for regeneration using contemporary biotechnologies. We emphasize the importance of studying gliosis as a reparative mechanism, rather than disregarding it as an unfortunate clinical prognosis in diseased retina.

YAP is critical to inflammation, endothelial-mesenchymal transition and subretinal fibrosis in experimental choroidal neovascularization

Subretinal fibrosis causes local damage to the retina and irreversible vision loss, as the final stage of neovascular age-related macular degeneration (nAMD). More recently, the endothelial-to-mesenchymal transition (EndoMT) has been considered one of the most significant sources of myofibroblasts in subretinal fibrosis, though the underpinning molecular mechanisms remain unclear. In this study, a series of experiments were performed to test the hypothesis that Yes-associated protein (YAP) may be involved in EndoMT and subretinal fibrosis. We demonstrated that transforming growth factor (TGF)-β2 stimulation induces YAP dephosphorylation (activated) and nuclear transcription in human umbilical vein endothelial cells (HUVECs) by increasing reactive oxygen species (ROS) levels. Moreover, TGF-β2-mediated EndoMT and proinflammatory cytokine production in HUVECs were reduced by ROS clearance or YAP knockdown. Furthermore, the severity of subretinal fibrosis was markedly relieved by intravitreal administration of a small interfering RNA targeting YAP in the mouse laser-induced choroidal neovascularization (CNV) model. Our findings provide novel insights into a previously unknown effect of YAP on the EndoMT process and reveal YAP as a potential target for suppressing CNV-related subretinal fibrosis and protect vision.

Bilateral neovascular age-related macular degeneration: unilateral regression following endophthalmitis with persistent activity in the fellow eye

A woman in her 70s who was being followed up for neovascular age-related macular degeneration (nAMD) in both eyes for 2 years with recalcitrant choroidal neovascularisation (CNV) and had an episode of acute endophthalmitis in one eye was identified. After treatment of postinjection culture-negative right eye (RE) endophthalmitis with intravitreal vancomycin and tazobactam, the patient had complete regression of treatment-resistant CNV in RE to date with postinfection follow-up of 2 years. In contrast, the fellow eye continued showing activity in the choroidal neovascular membrane that required antivascular endothelial growth factor injections on a pro re nata basis to date. Prolonged regression of nAMD for 3 years in the affected eye and continued activity in the fellow eye support the hypothesis that inflammation accompanying endophthalmitis or the drugs used for the treatment can have a role in the regression of nAMD.

Evolving treatment paradigms for PCV

Polypoidal choroidal vasculopathy (PCV) is a subtype of neovascular AMD (nAMD) that accounts for a significant proportion of nAMD cases worldwide, and particularly in Asia. Contemporary PCV treatment strategies have closely followed those used in typical nAMD, though there are significant gaps in knowledge on PCV management and it remains unclear if these strategies are appropriate. Current clinical trial data suggest intravitreal anti-vascular endothelial growth factor (VEGF) therapy alone or in combination with photodynamic therapy is effective in managing haemorrhage and exudation in PCV, although the optimal treatment interval, including as-needed and treat-and-extend approaches, is unclear. Newer imaging modalities, including OCT angiography and high-resolution spectral domain OCT have enabled characterisation of unique PCV biomarkers that may provide guidance on how and when treatment and re-treatment should be initiated. Treatment burden for PCV is a major focus of future therapeutic research and several newly developed anti-VEGF agents, including brolucizumab, faricimab, and new modes of drug delivery like the port delivery system, offer hope for dramatically reduced treatment burden for PCV patients. Beyond anti-VEGF therapy, recent developments in our understanding of PCV pathophysiology, in particular the role of choroidal anatomy and lipid mediators in PCV pathogenesis, offer new treatment avenues that may become clinically relevant in the future. This article explores the current management of PCV and more recent approaches to PCV treatment based on an improved understanding of this unique disease process.

Transcriptomic analysis of choroidal neovascularization reveals dysregulation of immune and fibrosis pathways that are attenuated by a novel anti-fibrotic treatment

Neovascular AMD (nAMD) leads to vision loss and is a leading cause of visual impairment in the industrialised world. Current treatments that target blood vessel growth have not been able to treat subretinal fibrosis and nAMD patients continue to lose vision. The molecular mechanisms involved in the development of fibrotic lesions in nAMD are not well understood. The aim of this study was to further understand subretinal fibrosis in the laser photocoagulation model of choroidal neovascularization (CNV) by studying the whole transcriptome of the RPE/choroid following CNV and the application of an anti-fibrotic following CNV. Seven days after laser induced CNV, RPE and choroid tissue was separated and underwent RNAseq. Differential expression analysis and pathway analysis revealed an over representation of immune signalling and fibrotic associated pathways in CNV compared to control RPE/choroid tissue. Comparisons between the mouse CNV model to human CNV revealed an overlap in upregulated expression for immune genes (Ccl2, Ccl8 and Cxcl9) and extracellular matrix remodeling genes (Comp, Lrcc15, Fndc1 and Thbs2). Comparisons between the CNV model and other fibrosis models showed an overlap of over 60% of genes upregulated in either lung or kidney mouse models of fibrosis. Treatment of CNV using a novel cinnamoyl anthranilate anti-fibrotic (OCX063) in the laser induced CNV model was selected as this class of drugs have previously been shown to target fibrosis. CNV lesion leakage and fibrosis was found to be reduced using OCX063 and gene expression of genes within the TGF-beta signalling pathway. Our findings show the presence of fibrosis gene expression pathways present in the laser induced CNV mouse model and that anti-fibrotic treatments offer the potential to reduce subretinal fibrosis in AMD.

Baseline predictors for subretinal fibrosis in neovascular age-related macular degeneration

To find baseline predictors for subretinal fibrosis (SF) in neovascular age-related macular degeneration (nAMD). Forty-five eyes of 45 participants with treatment-naïve nAMD were consecutively enrolled and treated according to a standardized treat-and-extend protocol. Spectral-domain optical coherence tomography (OCT), color fundus photography and fluorescein angiography as well as novel imaging modalities polarization-sensitive OCT and OCT angiography (OCTA) were performed to detect SF after 1 year and find baseline predictors for SF development. Baseline OCTA scans were evaluated for quantitative features such as lesion area, vessel area, vessel junctions, vessel length, vessel endpoints and mean lacunarity. Additionally, the type of macular neovascularization, the presence of subretinal fluid, intraretinal fluid (IRF), subretinal hyperreflective material (SHRM), retinal hemorrhage as well as best-corrected visual acuity (BCVA) were evaluated. After 12 months 8 eyes (18%) developed SF. Eyes with SF had worse baseline BCVA (p = .001) and a higher prevalence of IRF (p = .014) and SHRM at baseline (p = .017). There was no significant difference in any of the evaluated quantitative OCTA parameters (p > .05) between eyes with and without SF. There were no quantitative baseline microvascular predictors for SF in our study. Low baseline BCVA, the presence of IRF and SHRM, however, are easily identifiable baseline parameters indicating increased risk.

Emerging opportunities for C3 inhibition in the eye

The eye presents a unique opportunity for complement component 3 (C3) therapeutics. Drugs can be delivered directly to specific parts of the eye, and growing evidence has established a pivotal role for C3 in age-related macular degeneration (AMD). Emerging data show that C3 may be important to the pathophysiology of other eye diseases as well. This article will discuss the location of C3 expression in the eye as well as the preclinical and clinical data regarding C3's functions in AMD. We will provide a comprehensive review of developing C3 inhibitors for the eye, including the Phase 2 and 3 data for the C3 inhibitor pegcetacoplan as a treatment for the geographic atrophy of AMD. Developing evidence also points toward C3 as a therapeutic target for stages of AMD preceding geographic atrophy. We will also discuss data illuminating C3's relationship to other eye diseases, such as Stargardt disease, diabetic retinopathy, and glaucoma. In addition to being a converging point and centerpiece of the complement cascade, C3 has broad effects as a multifaceted controller of opsonophagocytosis, microglia/macrophage recruitment, and downstream terminal pathway activity. C3 is a crucial player in the pathophysiology of AMD but also seems to have importance in other diseases that are major causes of blindness. Directions for further investigation will be highlighted, as culminating evidence suggests that we may be approaching an era of C3 therapeutics for the eye.

Morphologic and Microvascular Differences Between Macular Neovascularization With and Without Subretinal Fibrosis

Purpose

To evaluate morphologic and microvascular differences between eyes with and without subretinal fibrosis (SF) caused by neovascular age-related macular degeneration (nAMD).

Methods

Patients with nAMD with a minimum history of 12 months of anti-VEGF treatment were prospectively included in this cross-sectional study. Patients were imaged using standard imaging, swept-source optical coherence tomography angiography for quantitative microvascular analysis and polarization-sensitive OCT as an ancillary method for automated SF segmentation. The presence of reticular pseudodrusen, hyperreflective foci (HRF), and outer retinal tubulation (ORT) were also evaluated.

Results

Sixty eyes of 60 participants (37 female) with nAMD and a mean 3.1 (±2.7)-year history of anti-VEGF treatment were included, 20 (33%) of which were diagnosed with SF. Eyes with SF had a higher prevalence of ORT (P < 0.001) and a lower prevalence of HRF (P = 0.004) than eyes without SF. Fifty eyes were analyzed quantitatively for microvascular biomarkers. Eyes with SF had a larger greatest vascular caliber (P = 0.001) and greatest linear diameter (P = 0.042), a larger microvascular neovascularization (MNV) area (P = 0.026), larger vessel area (P = 0.037), higher number of vessel junctions (P = 0.025), longer total vessel length (P = 0.027), higher number of vessel endpoints (P = 0.007), and higher endpoint density (P = 0.047).

Conclusions

This multimodal imaging approach demonstrated in vivo microvascular and morphological differences in eyes with and without SF. Eyes with SF tend to have larger MNV lesions with thicker vessels and are often associated with the presence of ORT.

Translational Relevance

This study points out imaging biomarkers in patients with SF, which may help identifying high-risk patients.

Three-Year Outcomes of Neovascular Age-Related Macular Degeneration in Eyes That Do Not Develop Macular Atrophy or Subretinal Fibrosis

Purpose

To report the 36-month treatment outcomes of eyes with neovascular age-related macular degeneration (nAMD) receiving vascular endothelial growth factor (VEGF) inhibitors in daily practice who did not develop either subretinal fibrosis (SRFi) or macular atrophy (MA).

Methods

This is a retrospective analysis of data from the Fight Retinal Blindness registry. Treatment-naïve eyes starting intravitreal injection of VEGF inhibitors for nAMD from January 1, 2010, to September 1, 2017, and did not have SRFI and MA at baseline were tracked.

Results

We identified 2478 eligible eyes, of which 1712 eyes did not develop SRFi or MA, 291 developed extrafoveal SRFI or MA, and 475 developed subfoveal SRFi or MA over 36 months. The estimated visual acuity stabilized from 6 months to 36 months in eyes that did not develop SRFI or MA with a mean (95% confidence interval [CI]) change in VA of −1 (−2, 0) letters, whereas eyes that developed extrafoveal (−3 [−5, −2] letters) or subfoveal (−10 [−11, −8] letters) SRFi or MA declined in vision in the same period. Eyes with no or extrafoveal SRFi or MA over 36 months were more likely to maintain their visual improvement from six months to 36 months (odds ratio [OR; 95% CI] = 2.3 [1.5, 3.3] for absence vs. subfoveal SRFi or MA, P ≤ 0.01 and OR = 2.0 [1.2, 3.4] for extrafoveal vs. subfoveal MA or SRFi, P = 0.01).

Conclusions

Treatment-naïve nAMD eyes receiving VEGF inhibitors maintain their initial six-month visual improvement over three years if they do not develop SRFI or MA.

Translational Relevance

The nAMD is still a major cause of blindness despite antiangiogenic treatments. We found that eyes that did not develop subretinal fibrosis or macular atrophy maintained their initial vision improvement for at least three years, suggesting that identifying treatments for these complications is the final barrier to achieving excellent outcomes in nAMD.

The Development of Macular Atrophy in Patients with Wet Age-Related Macular Degeneration Receiving Anti-VEGF Treatment

Age-related macular degeneration (AMD) is a leading cause of blindness. Late AMD can be classified into exudative (commonly known as wet AMD [wAMD]) or dry AMD, both of which may progress to macular atrophy (MA). MA causes irreversible vision loss and currently has no approved pharmacological treatment. The standard of care for wAMD is treatment with anti-vascular endothelial growth factors (VEGF). However, recent evidence suggests that anti-VEGF treatment may play a role in the development of MA. Therefore, it is important to identify risk factors for the development of MA in patients with wAMD. For example, excessive blockade of VEGF through intense use of anti-VEGF agents may accelerate the development of MA. Patients with type III macular neovascularisation (retinal angiomatous proliferation) have a particularly high risk of MA. These patients are characterised as having a pre-existing thin choroid (age-related choroidopathy), suggesting that the choroidal circulation is unable to respond to increased VEGF expression. Evidence suggests that subretinal fluid (possibly indicative of residual VEGF activity) may play a protective role. Patients receiving anti-VEGF agents must be assessed for overall risk of MA and there is an unmet medical need to prevent the development of MA without undertreating wAMD.

Long-Term Outcomes of Bacillary Layer Detachment in Neovascular Age-Related Macular Degeneration

PURPOSE

To evaluate the clinical characteristics, multimodal imaging features, and long-term treatment outcomes of eyes with neovascular age-related macular degeneration (nAMD) and bacillary layer detachment (BALAD) treated with intravitreal anti-VEGF therapy.

DESIGN

Retrospective, longitudinal, case series.

PARTICIPANTS

Treatment-naive patients with nAMD (n = 30) showing BALAD on OCT and undergoing anti-VEGF therapy.

METHODS

Clinical records and multimodal imaging results of up to 4 years after diagnosis were reviewed.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA) values were compared over time. The cumulative risk of and risk factors for subretinal fibrosis were assessed using Cox regression analyses, and adjusted hazard ratio (aHR) was computed.

RESULTS

Thirty eyes of 30 patients were included. Macular neovascularization (MNV) subtypes were distributed as follows: type 1, 63%; type 2, 27%; mixed type 1 and 2, 3%; type 3, 3%; aneurysmal type 1, 3%. The BCVA significantly improved after anti-VEGF loading phase (Snellen equivalent, from 20 of 118 to 20 of 71, P = 0.03), but it returned to the baseline levels at 4 years (Snellen equivalent, 20 of 103, P = 0.6). The cumulative risk of subretinal fibrosis was 77% at 4 years. The risk factors associated with subretinal fibrosis included hemorrhagic BALAD (aHR, 2.02; 95% confidence interval [CI] 1.54-3.22; P < 0.01) and the presence of subretinal hyperreflective material (aHR, 1.83; 95% CI 1.35-3.14; P < 0.01).

CONCLUSIONS

BALAD was found in association with all types of MNV in patients with nAMD. Long-term observation revealed poor functional outcomes related to the high risk of subretinal fibrosis.

PREVALENCE AND RISK FACTORS FOR THE DEVELOPMENT OF PHYSICIAN-GRADED SUBRETINAL FIBROSIS IN EYES TREATED FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

PURPOSE

To assess the prevalence and incidence of and risk factors for subretinal fibrosis (SRFi) in eyes with neovascular age-related macular degeneration (nAMD) that underwent vascular endothelial growth factor inhibitor treatment for up to 10 years.

METHODS

A cross-sectional and longitudinal analysis was performed on data from a neovascular age-related macular degeneration registry. The presence and location of SRFi were graded by the treating practitioner. Visual acuity, lesion characteristics (type, morphology, and activity), and treatment administered at each visit was recorded.

RESULTS

The prevalence of SRFi in 2,914 eyes rose from 20.4% at year interval 0-1 to 40.7% at year interval 9 to 10. The incidence in 1,950 eyes was 14.3% at baseline and 26.3% at 24 months. Independent characteristics associated with SRFi included poorer baseline vision (adjusted odds ratio 5.33 [95% confidence interval 4.66-7.61] for visual acuity ≤35 letters vs. visual acuity ≥70 letters, P < 0.01), baseline lesion size (adjusted odds ratio 1.08 [95% confidence interval 1.08-1.14] per 1000 µm, P = 0.03), lesion type (adjusted odds ratio 1.42 [95% confidence interval 1.17-1.72] for predominantly classic vs. occult lesions, P = 0.02), and proportion of active visits (adjusted odds ratio 1.58 [95% confidence interval 1.25-2.01] for the group with the highest level of activity vs. the lowest level of activity, P < 0.01).

CONCLUSION

Subretinal fibrosis was found in 40% of eyes after 10 years of treatment. High rates of lesion activity, predominantly classic lesions, poor baseline vision, and larger lesion size seem to be independent risk factors for SRFi.

Subretinal fibrosis in neovascular age-related macular degeneration: current concepts, therapeutic avenues, and future perspectives

Age-related macular degeneration (AMD) is a progressive, degenerative disease of the human retina which in its most aggressive form is associated with the formation of macular neovascularization (MNV) and subretinal fibrosis leading to irreversible blindness. MNVs contain blood vessels as well as infiltrating immune cells, myofibroblasts, and excessive amounts of extracellular matrix proteins such as collagens, fibronectin, and laminin which disrupts retinal function and triggers neurodegeneration. In the mammalian retina, damaged neurons cannot be replaced by tissue regeneration, and subretinal MNV and fibrosis persist and thus fuel degeneration and visual loss. This review provides an overview of subretinal fibrosis in neovascular AMD, by summarizing its clinical manifestations, exploring the current understanding of the underlying cellular and molecular mechanisms and discussing potential therapeutic approaches to inhibit subretinal fibrosis in the future.

Neovascular age-related macular degeneration: A review of findings from the real-world Fight Retinal Blindness! registry

The use of vascular endothelial growth factor (VEGF) inhibitors has revolutionised the treatment of neovascular age-related macular degeneration (nAMD) since the pivotal Phase III studies demonstrated their efficacy more than 10 years ago. The Fight Retinal Blindness! project was developed to track the treatment outcomes of patients with nAMD in real-world practice. Data from this registry have been used to answer several clinically relevant questions related to the treatment of nAMD including the effect of under-treatment, the comparative effectiveness of different anti-vascular endothelial growth factor agents, long-term treatment outcomes, identifying optimal treatment regimens and the rate and outcomes of rare adverse events. Observational studies are a valuable complement to the shortcomings of clinical trials and a combination of data from real-world settings and clinical trials are necessary to provide evidence on how to achieve the best outcomes for individual patients with nAMD.

Predictors of Visual Acuity After Treatment of Neovascular Age-Related Macular Degeneration - Current Perspectives

Visual acuity is a key outcome measure in the treatment of neovascular age-related macular degeneration (nAMD) using anti-vascular endothelial growth factor agents. Large variations in visual responses between individuals within clinical trials and real-world studies may relate to underlying differences in patient and treatment factors. Most notably, a better baseline visual acuity, younger age and smaller choroidal neovascularization lesion size have been strongly associated with achieving better visual outcomes. In addition, there is emerging evidence for other roles including genetic factors and anatomical variables such as fluid status. Apart from patient-related factors, treatments that favor a higher number of injections tend to provide better visual outcomes. Overall, the identification of predictive factors does not currently play an essential role in the clinical management of patients with nAMD. However, they have allowed for the understanding that early detection, timely management and close monitoring of the disease are required to achieve optimal visual outcomes. Further investigation into predictive factors alongside the development of novel therapeutic agents may one day provide a means to accurately predict patient outcomes. Treatment regimens that offer flexible dosing patterns such as the treat-and-extend strategy currently provide a degree of personalization during treatment.

Causes and Five-Year Proportion of New Irreversible Visual Impairment in Jinshan District, Shanghai, from 2009-2018

Purpose

To describe the age distribution and main causes of new registered irreversible visual impairment (VI) and to compare the five-year proportion of VI in Jinshan district, Shanghai, from 2009 to 2018.

Methods

The new irreversible VI data were collected in the registry system from the Disabled Persons' Federation in Jinshan district from January 1, 2009, to December 31, 2018. Age, gender, and causes of VI were included, and the 5-year proportion of VI was calculated.

Results

The peak occurrence of blindness occurred in the 50–59 yrs group in 2009–2013 and in the ≥70 yrs group in 2014–2018. The peak occurrence of low vision occurred in the 40–49 yrs group in 2009–2013 and in the 50–59 yrs group in 2014–2018. Myopic macular degeneration (MMD, 15.5%), diabetic retinopathy (DR, 14.3%), and other optic nerve atrophy (ONA, 14.3%) were the three leading causes of blindness in 2009-2013, whereas MMD (21.3%), age-related macular degeneration (AMD, 19.6%), ONA (14.9%) were the three leading causes of blindness in 2014–2018. MMD (39.2%), DR (9.6%), ONA (8.8%) were the three leading causes of low vision in 2009–2013, whereas MMD (38.7%), AMD (23.3%), ONA (7.4%) were the three leading causes of low vision in 2014–2018. The proportions of blindness and low vision caused by AMD were higher in 2014–2018 than those in 2009–2013 (P=0.034 and P < 0.001, respectively).

Conclusion

The present study demonstrated an increasing trend in the number of irreversibly visually impaired individuals from 2009 to 2018. More attention should be paid to people with high myopia and old age.

Losartan prevents tumor-induced hearing loss and augments radiation efficacy in NF2 schwannoma rodent models

Hearing loss is one of the most common symptoms of neurofibromatosis type 2 (NF2) caused by vestibular schwannomas (VSs). Fibrosis in the VS tumor microenvironment (TME) is associated with hearing loss in patients with NF2. We hypothesized that reducing the fibrosis using losartan, an FDA-approved antihypertensive drug that blocks fibrotic and inflammatory signaling, could improve hearing. Using NF2 mouse models, we found that losartan treatment normalized the TME by (i) reducing neuroinflammatory IL-6/STAT3 signaling and preventing hearing loss, (ii) normalizing tumor vasculature and alleviating neuro-edema, and (iii) increasing oxygen delivery and enhancing efficacy of radiation therapy. In preparation to translate these exciting findings into the clinic, we used patient samples and data and demonstrated that IL-6/STAT3 signaling inversely associated with hearing function, that elevated production of tumor-derived IL-6 was associated with reduced viability of cochlear sensory cells and neurons in ex vivo organotypic cochlear cultures, and that patients receiving angiotensin receptor blockers have no progression in VS-induced hearing loss compared with patients on other or no antihypertensives based on a retrospective analysis of patients with VS and hypertension. Our study provides the rationale and critical data for a prospective clinical trial of losartan in patients with VS.

ASSOCIATION BETWEEN ANATOMICAL AND CLINICAL OUTCOMES OF NEOVASCULAR AGE-RELATED MACULAR DEGENERATION TREATED WITH ANTIVASCULAR ENDOTHELIAL GROWTH FACTOR

PURPOSE

Assess the relationship between subretinal fluid (SRFL), intraretinal fluid, and visual outcomes of neovascular age-related degeneration in routine clinical practice.

METHODS

Treatment-naive eyes enrolled in the Fight Retinal Blindness! registry after January 2017 were identified. Lesion activity was graded at each visit as inactive, active not SRFL only (A-NSRFL only), or active SRFL only (A-SRFL only). Eyes were grouped based on initial activity as follows: 1) initially A-NSRFL only or 2) initially A-SRFL only, and their predominant activity status over 12 months was as follows: 1) mostly inactive, 2) mostly A-NSRFL only, or 3) mostly A-SRFL only.

RESULTS

Seven hundred and three eyes were eligible for analysis. Initially A-NSRFL only had a similar adjusted mean 12-month visual acuity change to initially A-SRFL eyes (5.7 vs. 6.9 letters; P = 0.165), but their final visual acuity was worse (62.5 vs. 67.5 letters at 12 months; P = 0.003). The adjusted mean 12-month visual acuity change between the predominant activity groups was significantly different (P = 0.005), with mostly inactive (7.6 letters) and mostly A-SRFL only (7.5 letters) eyes gaining more than mostly A-NSRFL only eyes (3.6 letters).

CONCLUSION

Eyes with SRFL only had similar outcomes at 1 year to eyes that were mostly inactive. Intraretinal fluid was associated with worse visual outcomes, highlighting the importance of distinguishing between intraretinal fluid and SRFL when managing neovascular age-related degeneration.

Early Predictive Factors of Visual Loss at 1 Year in Neovascular Age-Related Macular Degeneration under Anti-Vascular Endothelial Growth Factor

PURPOSE

To evaluate early predictive factors of visual loss in patients treated with anti-vascular endothelial growth factor (VEGF) injections under an as-needed regimen for neovascular age-related macular degeneration (AMD).

DESIGN

Post hoc analysis from the randomized controlled trial Groupe d'Evaluation Français Avastin versus Lucentis (GEFAL).

PARTICIPANTS

A total of 393 patients with neovascular AMD.

METHODS

The present analysis is based on 1-year data from patients included in the study. Patients were separately categorized according to the best-corrected visual acuity (BCVA) change at 3 months and 1 year into 3 trajectories: (1) patients with no vision loss ≥5 letters at 3 months and 1 year (absence of loss ≥5 letters); (2) patients with no vision loss ≥5 letters at 3 months but loss ≥5 letters at 1 year (secondary loss ≥5 letters); and (3) patients with vision loss ≥5 letters at 3 months and 1 year (initial loss ≥5 letters).

MAIN OUTCOME MEASURES

The following factors were evaluated at baseline and 3 months: age, sex, BCVA, presence of fluid, central macular thickness, angiographic choroidal neovascularization (CNV) subtype, CNV area measured in disc area on fluorescein angiography, and number of intravitreal injections.

RESULTS

An absence of loss ≥5 letters was found in 225 patients (57.3%), a secondary loss ≥5 letters after 3 months was found in 109 patients (27.7%), and an initial loss ≥5 letters was found in 59 patients (15%). Baseline characteristics were comparable among the 3 groups except for the total CNV area, which was larger in the initial and secondary loss groups (P = 0.0412). At 3 months, a significant association was found between presence of subretinal fluid (SRF) (P = 0.0318) and vision loss ≥5 letters, and an even stronger significant association between the presence of intraretinal fluid (IRF) (P = 0.0066) and vision loss ≥5 letters.

CONCLUSIONS

In the present study, we found that a large CNV area at baseline was significantly associated with initial or secondary loss of visual acuity ≥5 letters despite anti-VEGF injection. The presence of fluid, both SRF and IRF, at 3 months was found in patients with poorer trajectories.

Localized Optical Coherence Tomography Precursors of Macular Atrophy and Fibrotic Scar in the Comparison of Age-Related Macular Degeneration Treatments Trials

PURPOSE

To identify precursors of macular atrophy (MA) and of fibrotic scar (FS) in eyes treated with anti-vascular endothelial growth factor through pixel-mapping analysis of baseline optical coherence tomography (OCT).

METHODS

Design: Cross-sectional analysis.

SETTING

Multicenter clinical trial.

PATIENT POPULATION

68 eyes from the Comparison of Age-Related Macular Degeneration Treatments Trials.

INTERVENTION

Treatment with anti-vascular endothelial growth factor agents.

MAIN OUTCOME MEASURE

The percentage of MA or FS pixels with each OCT feature at baseline, and the odds ratio for baseline pixels with an OCT feature to develop MA or FS.

RESULTS

Retinal pigment epithelium atrophy and photoreceptor loss on OCT were highly predictive of MA at that location at years 2 and 5 (P < .0001), but accounted for only 22.5% of the ensuing atrophy at year 2 and less at year 5. Among pixels of MA at year 2, 78% were preceded by thick drusen, 54% by subretinal macular neovascularization (MNV), and 22.5% by no detectable OCT features. MNV, subretinal hyperreflective material, pigment epithelial detachment, intraretinal fluid, and sub-retinal pigment epithelium fluid were predictive of FS at that location (P values <.05). More than 75% of the pixels of FS at years 2 and 5 were preceded by pixels of baseline MNV.

CONCLUSIONS

Most pixels of FS were preceded by components of neovascularization. Although one-quarter of MA was accounted for by pre-existing evidence of atrophy on OCT alone, the development of MA in areas of thick drusen, areas with and without subretinal MNV lesion, and areas without detectable OCT precursors argues that the development of MA is multifactorial and may follow, in part, a non-neovascular pathway.

Incidence and Progression of Nongeographic Atrophy in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT) Clinical Trial

Importance

Retinal hypopigmentation and hyperpigmentation are precursors of geographic atrophy (GA). Incidence and progression to GA in eyes treated with anti-vascular endothelial growth factor for neovascular age-related macular degeneration (nAMD) have not been investigated.

Objective

To determine the incidence and progression of non-GA (NGA) and associated risk factors.

Design, Setting, and Participants

This study is a post hoc analysis of a cohort study within the Comparison of Age-Related Treatments Trials (CATT) clinical trial. Participants were recruited February 20, 2008, through December 9, 2009; released from protocol follow-up and treatment after 2 years; and recalled from March 14, 2014, through March 31, 2015. Data analyses were conducted from January 11, 2019, through November 27, 2019.

Interventions

Participants were randomized to ranibizumab or bevacizumab for (1) 2 years of monthly or as-needed injections or (2) monthly injections for 1 year and as-needed injections the following year. Participants were treated according to best medical judgement thereafter.

Main Outcomes and Measures

Incidence of nAMD-associated NGA (hypopigmentation and hyperpigmentation in color images) and progression; adjusted risk ratios (aRR) for baseline characteristics.

Results

Among 1107 participants, risk of NGA was 35% (391 eyes), 59% (246 eyes), and 81% (122 eyes) at 1, 2, and 5 years, respectively. Risk factors for NGA included worse visual acuity (20/200-20/320: aRR, 1.74 [95% CI, 1.24-2.43], compared with ≤20/40; P = .006), larger neovascularization area (>4 disc areas: aRR, 1.31 [95% CI, 1.01-1.71], compared with ≤1 disc areas; P = .007), switched drug regimen (aRR, 1.28 [95% CI, 1.06-1.54], compared with as-needed injections; P = .02), and single-nucleotide variants Age-Related Maculopathy Susceptibility 2 (ARMS2) (TT variant: relative risk [RR], 1.53 [95% CI, 1.22-1.93]; P = .001) and HtrA Serine Peptidase 1 (HTRA1) (AG variant: RR, 1.23 [95% CI, 1.01-1.48]; AA variant: RR, 1.51 [95% CI, 1.20-1.91]; P = .002). Sub-retinal pigment epithelium thickness was protective (>275 μm: aRR, 0.59 [95% CI, 0.46-0.75], compared with ≤75 μm; P < .001). Among 389 eyes with NGA by 2 years and subsequent color images, risk of progression to GA was 29%, 43%, and 50% at 1, 3, and 4 years, respectively. Risk factors for progression to GA included worse visual acuity (20/200-20/320: aRR, 2.75 [95% CI, 1.54-4.93], compared with ≤20/40; P < .001), worse fellow-eye visual acuity (<20/40: aRR, 1.77 [95% CI, 1.12-2.79], compared with ≥20/40; P = .01), fellow-eye GA (aRR, 1.71 [95% CI, 1.06-2.75]; P = .03), and pseudodrusen in either eye (aRR, 1.65 [95% CI, 1.17-2.34]; P = .005). Subretinal fluid was associated with a decreased risk of progression (aRR, 0.42 [95% CI, 0.28-0.63]; P < .001).

Conclusions and Relevance

In this study, after 2 years of protocol-guided anti-vascular endothelial growth factor treatment for nAMD, more than half of the eyes in the study developed NGA in the location of nAMD. After 3 additional years of regular care, half of them progressed to GA.

Trial Registration

ClinicalTrials.gov Identifier: NCT00593450.

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.

Principal Cause of Poor Visual Acuity after Neovascular Age-Related Macular Degeneration: Age-Related Eye Disease Study 2 Report Number 23

PURPOSE

To analyze the principal cause for poor vision in eyes with best-corrected visual acuity (BCVA) of 20/200 or worse 2 years after neovascular age-related macular degeneration (nAMD).

DESIGN

Prospective cohort study of participants enrolled in a clinical trial of oral supplements.

PARTICIPANTS

Age-Related Eye Disease Study 2 (AREDS2) participants whose eyes began anti-vascular endothelial growth factor (VEGF) therapy for incident nAMD and had data available at 2 years.

METHODS

Participants underwent refracted BCVA testing, ophthalmoscopic examination, and fundus photography at baseline and annual visits. Self-reports of anti-VEGF injections were collected.

MAIN OUTCOME MEASURES

Principal cause of BCVA of 20/200 or worse at 2 years, detected on fundus photography grading.

RESULTS

Of the 594 eligible eyes, the number with BCVA of 20/200 or worse at 2 years was 56 (9.4%). Mean BCVA was 14.9 letters (standard deviation [SD], 12.3 letters; Snellen equivalent, 20/500), versus 70.1 letters (SD, 12.8 letters; Snellen equivalent, 20/40) in the other group. Of the 55 eyes with fundus photography available at 2 years, 33 (60.0%) had central macular atrophy and 22 (40.0%) had central subretinal fibrosis assessed as the principal cause for poor vision. The group with poor BCVA had a higher proportion of non-White participants (8.9% vs. 1.7%; P = 0.006), lower BCVA 2 years earlier (mean, 38.0 letters [SD, 26.7 letters; Snellen equivalent, 20/160] vs. 71.8 letters (SD, 11.9 letters; Snellen equivalent, 20/40]; P < 0.0001), higher proportion with macular atrophy 2 years earlier (26.8% vs. 12.3%; P = 0.003), higher proportion with macular hemorrhage (25.5% vs. 13.2%; P = 0.014), and fewer anti-VEGF injections (7.6 vs. 10.2; P = 0.001).

CONCLUSIONS

Visual acuity data and fundus photography were obtained in a clinical trial environment, but were related to anti-VEGF therapy given in routine clinical practice. At 2 years after starting anti-VEGF therapy, almost 1 in 10 eyes showed BCVA at the level of legal blindness. From fundus photography grading, the cause of poor vision appeared to be macular atrophy in 60% and subretinal fibrosis in 40%. These data may be useful in understanding the long-term limits to good vision in nAMD.

3-Methyladenine Alleviates Experimental Subretinal Fibrosis by Inhibiting Macrophages and M2 Polarization Through the PI3K/Akt Pathway

Purpose: To explore the effects of 3-methyladenine (3-MA), a selective inhibitor of phosphatidylinositol-3-kinase (PI3K), on experimental subretinal fibrosis (SRF) in mice. Methods: The SRF mouse model was established by 532 nm laser photocoagulation at each fundus of mice on day 0. 3-MA was administered every 2 days from day 0 to 35. Immunofluorescence of choroidal flat mounts was performed to evaluate the size of SRF area, local macrophages, and polarization, respectively. Besides, Western blot analysis was carried out to assess the expression levels of macrophage polarization-related genes, Arg-1, Ym-1, and transforming growth factor-β₂ (TGF-β₂). Co-culture and migration experiments were used to demonstrate the inhibitory effect of 3-MA on fibroblasts. The gene knockout and Western blot analysis were used to explore the signal pathways related to macrophage polarization. Results: Compared with the control group, the 3-MA-treated group showed significantly less size of SRF area. 3-MA treatment reduced both circulating and local macrophages, and counteracted M2 polarization. Moreover, 3-MA inhibited fibroblast recruitment. Mechanistically, we proved that 3-MA inhibits macrophage M2 polarization by suppressing PI3K/Akt signal pathway rather than the PI3K-autophagy-related signal pathway. Conclusions: 3-MA exerts antifibrotic effects on experimental SRF by targeting circulating and local macrophages and M2 polarization, through PI3K/Akt signal pathway. These results support the potential use of 3-MA as a new therapeutic modality for SRF associated with neovascular age-related macular degeneration.

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

PURPOSE

To describe the spectral-domain optical coherence tomography (OCT) features of fibrotic lesions associated with neovascular age-related macular degeneration (nAMD) and to outline the progression pathways from initial macular choroidal neovascular lesions (CNVs) to fibrosis.

METHODS

Patients with nAMD were retrospectively included when macular subretinal fibrosis was present. Fibrosis was categorized using spectral-domain OCT with respect to retinal pigment epithelium (RPE) in 836 spectral-domain OCT slices from 44 eyes of 39 patients. In addition, in 47 distinct eyes, 4181 spectral-domain OCT slices were retrospectively reviewed to longitudinally assess progression from the initial lesion to the final fibrosis.

RESULTS

Cross-sectional analysis classified fibrosis on spectral-domain OCT slices, as type A if located underneath the RPE, as type B if located above the RPE, and as type C if the remaining RPE was undistinguishable. The longitudinal analysis series revealed 3 progression pathways from the original CNV: 1) progression to type A, followed by RPE erosion and subretinal hyperreflective material, then type B and type C fibroglial lesion (FGL; 17/47 eyes); 2) progression to type B then type C FGL (17/47 eyes); and 3) persistence of type A with development of a flat, fibroatrophic lesion (13/47 eyes). Subretinal hyperreflective material, macular hemorrhage, or RPE tear occurred in 14 of 47, 13 of 47, and 10 of 47 eyes, respectively.

CONCLUSION

This spectral-domain OCT analysis identified various patterns of macular fibrosis in eyes with nAMD. Three pathways of progression to fibrosis were described including the well-established pathway of type 2 CNV progression to FGL and the progression of type 1 fibrovascular CNV to FGL or fibroatrophic lesion.