DRUSEN SUBTYPES AND CHOROIDAL CHARACTERISTICS IN ASIAN EYES WITH TYPICAL NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

Pachychoroid disease: review and update

The pachychoroid disease spectrum is a phenotype characterized by alterations in choroidal vasculature which result in outer retinal and choriocapillaris damage and visual loss. The presence of pachyvessels is one of the key features of the pachychoroid phenotype. Recent imaging studies suggest that pachyvessels may form because of choroidal venous congestion in one or more quadrants. The formation of intervortex anastomosis may function as a compensatory mechanism to dissipate the increased venous pressure, while outflow obstruction has been hypothesized to occur at the site of the vortex vein exiting the sclera. This review aims to summarize recent imaging findings and discuss evolution in the understanding of pathogenesis of the pachychoroid disease spectrum. We have summarized notable treatment trials in central serous chorioretinopathy and polypoidal choroidal vasculopathy and included an update of the current diagnostic and management strategies of the entities that are part of the pachychoroid disease spectrum.

The potential key role of choroidal non-perfusion and rod degeneration in the pathogenesis of macular neovascularization type 3

Macular neovascularization type 3 (MNV3) is a multifactorial disease with distinct epidemiological, clinical, pathomorphological and topographical characteristics. This review of the literature discusses the latest experimental and clinical outcomes that could explain the pathogenesis of retinal neovascularization. Although patients with MNV3 are usually older than those with MNV1 or 2, their lesions do not coexist with, precede, or follow other types in the same eye. The regional distribution of MNV3 lesions is characterized as confined to the parafoveal macula without any involvement of the rod-free foveal area. Focal outer retinal atrophy and choroidal non-perfusion are the main structural features that occur prior to the development of retinal neovascularization. Also, histological and experimental studies of MNV3 and other non-neovascular age-related macular degeneration diseases complicated with MNV3-like lesions strongly suggest rod degeneration contributes to the pathogenesis. Therefore, the retinal neovascularization in MNV3 has a different pathogenesis from the choroidal neovascularization in MNV1 and 2 and emerging evidence indicates that choroidal non-prefusion and rod degeneration play a key role in the pathogenesis of MNV3. Accordingly, we suggest a sequence of pathological events that start with choroidal non-perfusion due to advanced age followed by hypoxia of the outer retina at the parafoveal area. This induces a remarkable degeneration of rods that triggers the growth of retinal neovascularization due to the imbalance of the angiogenic factors in the outer retina.

Peripapillary retinal neovascularization and vitreous hemorrhage secondary to peripapillary pachychoroid syndrome

Purpose

To report a case of peripapillary pachychoroid syndrome (PPS) complicated with peripapillary retinal neovascularization causing vitreous hemorrhage.

Observation

A 42-year-old man, with a history of a visual loss of the right eye (RE) for 4 years, presented for ophthalmological examination. Best-corrected visual acuity was «counting fingers» in the RE and 20/25 in the left eye. Fundus examination showed irregular pattern of hypopigmentation of the retinal pigmented epithelium in both eyes with retinal neovessels in the peripapillary region of the RE. Swept-source optical coherence tomography demonstrated a central serous pigment epithelial detachment with intraretinal cysts and serous retinal detachment in the nasal macula extending from the temporal disc margin in the RE. Fluorescein angiography showed multiple areas of hyperfluorescence without clear distinction of retinal neovessels. Indocyanine green angiography showed patches of choroidal hyperpermeability predominant in the peripapillary region in both eyes. Optical coherence tomography angiography provided a good visualization of the papillary and retinal neovessels without signs of choroidal neovascularization. Two months after initial examination, the patient presented with vitreous hemorrhage associated to juxtapapillary preretinal hemorrhage in the RE. After vitreous injections of bevacizumab, we observed a total resolution of the vitreous hemorrhage a partial decrease of the intraretinal and subretinal fluid.

Conclusions and importance

We report an unusual case of peripapillary retinal neovascularization and vitreous hemorrhage complicating a PPS. OCTA was useful to detect retinal neovessels and peripapillary retinal and choriocapillaris hypoperfusion, supporting the understanding of the pathogenic mechanism of neovascularization in PPS.

Incidence and multimodal imaging characteristics of macular neovascularisation subtypes in Chinese neovascular age-related macular degeneration patients

AIMS

To investigate the incidence of macular neovascularisation (MNV) subtypes of neovascular age-related macular degeneration (nAMD) and summarise these subtypes' clinical features in the Chinese population using multimodal imaging.

METHODS

We retrospectively analysed 506 consecutive treatment-naïve nAMD patients (582 eyes). Incidence of MNV subtypes and clinical features were recorded based on their multimodal images. The classification of MNV subtypes in nAMD patients were referred to Consensus on Neovascular Age-related Macular Degeneration Nonmenclature (CONAN) study group classifications.

RESULTS

460 eyes of 389 nAMD patients were included in our study. 68.5% (315/460) of nAMD eyes were from male. According to CONAN, we identified type 1 macular neovascularisation (MNV) in 61.1% of eyes (281/460), type 2 MNV in 16.3% of eyes (75/460), type 3 MNV in 2.0% of eyes (9/460), mixed type 1 and type 2 MNV in 20.6% of eyes (95/460). 58% of eyes (267/460) were diagnosed as polypoidal choroidal vasculopathy lesions (PCV). 45.2% of eyes (208/460) with PCV lesions were type 1 MNV and 12.8% of eyes (59/460) with PCV lesions were co-occurred with type 2 MNV.

CONCLUSION

Based on the consensus anatomical classification system developed by the CONAN Study Group, we updated the incidence of MNV subtypes and found that PCV was the most common subtype and type 3 MNV was the least common subtype among Chinese nAMD patients. In addition, the co-occurrence of PCV and type 2 MNV was typically observed, and its frequency was reported in our study.

Prevalence and risk factors for age-related macular degeneration in a population-based cohort study of older adults in Northern Ireland using multimodal imaging: NICOLA Study

PURPOSE

To report prevalence and risk factor associations for age-related macular degeneration (AMD) and AMD features from multimodal retinal grading in a multidisciplinary longitudinal population-based study of aging in Northern Ireland.

STUDY DESIGN

Population-based longitudinal cohort study.

METHODS

Retinal imaging at the Norther Ireland Cohort for the Longitudinal Aging Study health assessment included stereo Colour Fundus Photography (CFP) (Canon CX-1, Tokyo, Japan) and Spectral-Domain Optical Coherence Tomography (SD-OCT) ((Heidelberg Retinal Angopgraph (HRA)+OCT; Heidelberg Engineering, Heidelberg, Germany). Medical history and demographic information was obtained during a home interview. Descriptive statistics were used to describe the prevalence of AMD and individual AMD features. Multiple imputation followed by multiple regression modelling was used to explore risk factor associations including relationships with AMD genetic risk score.

RESULTS

Retinal images from 3386 participants were available for analysis. Mean age of the sample was 63.4 (SD 9.01, range: 36-99). Population weighted prevalence of AMD using colour grading in those over 55 years was: no drusen: 6 0.4%; drusen <63 μm: 15.9%; drusen 63-125 µm: 13.7%; drusen >125 µm or pigmentary changes: 8.3%; late AMD: 1.6%. Prevalence of AMD features in those over 55 years was: OCT drusen 27.5%, complete outer retinal pigment epithelium and outer retinal atrophy (cRORA) on OCT was 4.3%, reticular drusen 3.2% and subretinal drusenoid deposits 25.7%. The genetic risk score was significantly associated with drusen and cRORA but less so for SDD alone and non-significant for hyperpigmentation or vitelliform lesions.

CONCLUSIONS

Multimodal imaging-based classification has provided evidence of some divergence of genetic risk associations between classical drusen and SDD. Our findings support an urgent review of current AMD severity classification systems.

The Relationship between Dietary Calcium and Age-Related Macular Degeneration

BACKGROUND

Mineral element supplements are widely used in the older adult population. However, little is known of their impact on the progression of age-related macular degeneration (ARMD). The aim of this study was to examine the association between dietary micronutrients and ARMD in older adults.

METHODS

We enrolled 5227 participants from the National Health and Nutrition Examination Survey (NHANES 2005-2008) in this cross-sectional study. ARMD was evaluated using an ophthalmic digital imaging system and digital camera. Mineral element consumption was collected using a 24-hour dietary recall. The association between mineral element use and the presence of ARMD was determined by multivariable logistic regression.

RESULTS

After adjusting for relevant variables, dietary calcium was negatively associated with ARMD (OR: 680, 95%CI: 0.482-0.960). In contrast to dietary form, serum concentration of calcium was not associated with ARMD. Moreover, increased dietary calcium was associated with reduced ARMD (OR: 0.684, 95%CI: 0.468-1.000).

CONCLUSION

A lower consumption of dietary calcium was significantly associated with a higher risk of ARMD. Further longitudinal studies are necessary to explore these findings.

Towards a better understanding of non-exudative choroidal and macular neovascularization

Non-exudative macular and choroidal neovascularization (MNV and CNV) usually refers to the entity of treatment-naïve type 1 neovascularization in the absence of associated signs of exudation. Histopathological studies, dating back in the early 70s, identified the presence of non-exudative MNV, but the first clinical report of this finding was in the late 90s using indocyanine green angiography in eyes with age-related macular degeneration (AMD). With more advanced retinal imaging, there has been an ever increasing appreciation of non-exudative MNV associated with AMD and CNV with other macular disorders. However, consensus regarding the exact definition and the clinical management of this entity is lacking. Furthermore, there may be variation in the imaging features and clinical course suggesting that a spectrum of disease may exist. Herein, we review the large body of published work that has provided a better understanding of non-exudative MNV and CNV in the last decade. The prevalence, multimodal imaging features, clinical course, and response to treatment are discussed to elucidate further key insights about this entity. Based on these observations, this review also proposes a new theory about the origin and course of different sub-types of non-exudative MNV/CNV which can have different etiologies and pathways according to the clinical context of disease.

Early Stages of Age-Related Macular Degeneration: Racial/Ethnic Differences and Proposal of a New Classification Incorporating Emerging Concept of Choroidal Pathology

The progression of age-related macular degeneration (AMD) is determined by environmental and genetic factors, and phenotypic or molecular risk factors have been investigated extensively. Interestingly, risk factor profiles for advanced AMD differ among individuals, and one of the causes of variation may be explained by their ethnic background. Recent advances in retinal imaging technology have led to the identification of previously unrecognized risk factors for advanced AMD on optical coherence tomography (OCT) and OCT angiography, which expands the concept of traditional imaging risk factors such as drusen and pigmentary abnormalities visible on color fundus photographs. This OCT imaging modality has identified novel pathognomonic changes for early AMD, including the associated photoreceptor, retinal pigment epithelium, and underlying choroidal changes. Regarding features of multimodal imaging associated with the presence or progression of geographic atrophy, there is an international expert consensus classification system; however, features associated with the progression of macular neovascularization (MNV) are still obscure. To make a consensus towards understanding features associated with the risk of MNV, this review focuses on the early stages of AMD by summarizing imaging characteristics and early signs and classifications in view of advanced multimodal imaging technology. Recent evidence suggests that neovascular AMD is not a single disease entity but a heterogeneous disease characterized by MNV. Besides drusen, OCT features associated with pigment abnormalities, such as shallow irregular RPE elevation (SIRE, also known as double-layer sign), pachychoroid pigment epitheliopathy, and choriocapillaris ischemia, seem to confer a high risk of MNV developing, especially for Asian populations.

Choroidal Vasculature Changes in Age-Related Macular Degeneration: From a Molecular to a Clinical Perspective

The contribution of choroidal vasculature to the pathogenesis of age-related macular degeneration (AMD) has been long debated. The present narrative review aims to discuss the primary molecular and choroidal structural changes occurring with aging and AMD with a brief overview of the principal multimodal imaging modalities and techniques that enable the optimal in vivo visualization of choroidal modifications. The molecular aspects that target the choroid in AMD mainly involve human leukocyte antigen (HLA) expression, complement dysregulation, leukocyte interaction at Bruch’s membrane, and mast cell infiltration of the choroid. A mechanistic link between high-risk genetic loci for AMD and mast cell recruitment has also been recently demonstrated. Recent advances in multimodal imaging allow more detailed visualization of choroidal structure, identifying alterations that may expand our comprehension of aging and AMD development.

Correlation between Macular Neovascularization (MNV) Type and Druse Type in Neovascular Age-Related Macular Degeneration (AMD) Based on the CONAN Classification

To investigate associations and predictive factors between macular neovascularization (MNV) lesion variants and drusen types in patients with treatment-naïve neovascular age-related macular degeneration (AMD). Methods: Multimodal imaging was retrospectively reviewed for druse type (soft drusen, subretinal drusenoid deposits (SDDs) or mixed) and MNV type (MNV 1, MNV 2, MNV 1/2 or MNV 3). The Consensus on Neovascular AMD Nomenclature (CONAN) classification was used for characterizing MNV at baseline. Results: One eye of each eligible patient was included (n = 191). Patients with predominant SDDs had an increased adjusted odds ratio (aOR) for MNV 2 (23.4453, p = 0.0025) and any type of MNV 3 (8.7374, p < 0.0001). Patients with MNV 1/2 had an aOR for predominant SDDs (0.3284, p = 0.0084). Patients with MNV1 showed an aOR for SDDs (0.0357, p < 0.0001). Eyes with SDDs only without other drusen types showed an aOR for MNV 2 (9.2945, p < 0.0001). Conclusions: SDDs represent a common phenotypic characteristic in AMD eyes with treatment-naïve MNV. The aOR for eyes with predominant SDDs to develop MNV 2 and MNV 3 was much higher, possibly due to their location in the subretinal space. The predominant druse type may help to predict which type of MNV will develop during the course of AMD.

Association of Fundus Autofluorescence Abnormalities and Pachydrusen in Central Serous Chorioretinopathy and Polypoidal Choroidal Vasculopathy

A specific form of drusen, known as pachydrusen, has been demonstrated to be associated with pachychoroid eye diseases, such as central serous chorioretinopathy (CSC) and polypoidal choroidal vasculopathy (PCV). These pachydrusen have been found in up to 50% of eyes with CSC and PCV and may affect the disease progression and treatment response. This study aims to investigate the association between pachydrusen and changes in fundus autofluorescence (FAF) in eyes with CSC and PCV. A total of 65 CSC patients and 32 PCV patients were evaluated. Pachydrusen were detected using both color fundus photography and spectral-domain optical coherence tomography. The relationships between pachydrusen and FAF changes were then investigated. The prevalence of pachydrusen in CSC and PCV eyes was 16.7% and 61.8%, respectively. The mean age of patients with pachydrusen was significantly older than those without pachydrusen (CSC: 56.3 vs. 45.0 years, p < 0.001; PCV: 68.8 vs. 59.5 years, p < 0.001). No significant difference was found in the mean subfoveal choroidal thickness between eyes with or without pachydrusen. Eyes with pachydrusen were significantly associated with more extensive FAF changes in both CSC and PCV (p < 0.001 and p = 0.037, respectively). The study demonstrated that pachydrusen are more prevalent in PCV than CSC. Increasing age and more extensive abnormalities in FAF are associated with the presence of pachydrusen, suggesting that dysfunction of retinal pigment epithelial cells is associated with pachydrusen.

The Association of Pachydrusen Characteristics with Choroidal Thickness and Patient's Age in Polypoidal Choroidal Vasculopathy versus Central Serous Chorioretinopathy

We investigated the relationship between pachydrusen and choroidal thickness and age in eyes with polypoidal choroidal vasculopathy (PCV) and fellow eyes, compared to eyes with central serous chorioretinopathy (CSC). This retrospective study included 89 eyes with PCV and 146 eyes with CSC. The number, location, and shape of the pachydrusen and their association with choroidal thickness and age were analyzed. PCV eyes showed pachydrusen more frequently than eyes with CSC (52% vs. 20%, p < 0.001). Large solitary type and clustered type were more frequent in PCV eyes compared to CSC eyes (p = 0.003 and p = 0.001, respectively). Subfoveal choroidal thickness was associated with pachydrusen in eyes with PCV (odds ratio [OR] 1.006, 95% confidence interval [CI] 1.001−1.011, p = 0.027), while age was associated with pachydrusen in CSC eyes (OR 1.137, 95% CI, 1.073−1.205; p < 0.001). Pachydrusen were localized directly over the pachyvessel on optical coherence tomographic findings in approximately two thirds of PCV eyes and fellow eyes (62% and 67%, respectively). Risk factors for pachydrusen differ according to diseases. The presence of pachydrusen was associated with choroidal thickness in PCV, while the association with age was more prominent in CSC.

Pigmentary abnormality without significant drusen as a risk factor for late age-related macular degeneration

We investigated the incidence and risk factors of late age-related macular degeneration (AMD) in the fellow eye (FE) without significant drusen of patients with unilateral exudative macular neovascularization (MNV). In this retrospective study, 241 eligible patients who were followed-up for more than 3 years were enrolled. We analyzed the incidence and hazard ratios (HRs) of late AMD in the FE according to demographic and ophthalmologic variables. Hypopigmentation on color fundus photography (CFP) corresponds to shallow irregular RPE elevation (SIRE), so-called "double-layer sign" and/or "attenuation or disruption of RPE and/or ellipsoid zone" on OCT. The 5-year incidence of FE exudative MNV conversion was 8.6%. The 5-year incidence of FE exudative MNV of large hypopigmentation (≥ 0.5 disc area; DA) and small hypopigmentation (< 0.5 DA) on CFP, and SIRE (≥ 1000 µm) and small RPE elevation (< 1000 µm) on OCT were 36.2%, 14.2%, 55.0%, and 15.6%, respectively. The multivariate Cox proportional hazard model revealed that large hypopigmentation, small hypopigmentation, SIRE, and small RPE elevation showed HRs of 23.230, 8.037, 132.589, and 41.823 for FE exudative MNV occurrence, respectively. Hypopigmentation on CFP and SIRE on OCT could represent the same lesion. Even small hypopigmentation and small RPE elevation were significant risk factors for progression to exudative MNV.

Drusen and pigment abnormality predict the development of neovascular age-related macular degeneration in Japanese patients

Drusen are known to be the important hallmark to predict the development of age-related macular degeneration (AMD). The prevalence of drusen is lower in Asians compared with Caucasians so that the role of signs constituting early AMD is not well established in Asian populations as in Western countries. In this study, we retrospectively investigated clinical characteristics and 5-year incidence of neovascular AMD (nAMD) in the fellow eye of unilateral nAMD patients. Of 296 consecutive unilateral nAMD patients who had been followed up more than 5 years, 170 typical AMD, 119 polypoidal choroidal vasculopathy, and 7 retinal angiomatous proliferation were included. To examine factors associated with nAMD occurrence in the fellow eye, drusen and pigmentary abnormality in the fellow eye were classified into 4 categories; Category 1: no or small drusen < 63 μm (37.2%), Category 2: 63–125 μm medium drusen or pigmentary abnormality (22.2%), Category 3: large drusen > 125 μm (25.0%), Category P: pachydrusen (15.5%). The mean sub-foveal choroidal thickness (SFCT) was Category 1: 276 μm, Category 2: 308 μm, Category 3: 246 μm, and Category P: 302 μm, respectively. Of note, SFCT in Category 2 and Category P was significantly larger than those of Category 3. Finally, the 5-year incidence of nAMD in the fellow eye was 32/296 (10.8%); Category 1: 0/110 (0%), Category 2: 12/66 (18.2%), Category 3: 20/74 (27.0%), and Category P: 0/46 (0%). Thus, signs of intermediate AMD (large drusen) as well as those of early AMD, especially the pigmentary abnormality, may contribute to development of bilateral nAMD in Japanese patients.

Distinguishing retinal angiomatous proliferation from polypoidal choroidal vasculopathy with a deep neural network based on optical coherence tomography

This cross-sectional study aimed to build a deep learning model for detecting neovascular age-related macular degeneration (AMD) and to distinguish retinal angiomatous proliferation (RAP) from polypoidal choroidal vasculopathy (PCV) using a convolutional neural network (CNN). Patients from a single tertiary center were enrolled from January 2014 to January 2020. Spectral-domain optical coherence tomography (SD-OCT) images of patients with RAP or PCV and a control group were analyzed with a deep CNN. Sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUROC) were used to evaluate the model's ability to distinguish RAP from PCV. The performances of the new model, the VGG-16, Resnet-50, Inception, and eight ophthalmologists were compared. A total of 3951 SD-OCT images from 314 participants (229 AMD, 85 normal controls) were analyzed. In distinguishing the PCV and RAP cases, the proposed model showed an accuracy, sensitivity, and specificity of 89.1%, 89.4%, and 88.8%, respectively, with an AUROC of 95.3% (95% CI 0.727-0.852). The proposed model showed better diagnostic performance than VGG-16, Resnet-50, and Inception-V3 and comparable performance with the eight ophthalmologists. The novel model performed well when distinguishing between PCV and RAP. Thus, automated deep learning systems may support ophthalmologists in distinguishing RAP from PCV.

Macular neovascularization in eyes with pachydrusen

The natural history and clinical significance of pachydrusen is unclear. This study aims to compare the longitudinal changes of eyes with pachydrusen and soft drusen and progression to exudative macular neovascularisation (MNV). Patients with a diagnosis of MNV in one eye only and the fellow eye was selected as the study eye. Study eyes were required to have pachydrusen or soft drusen on fundus photographs and follow up of at least 2 years or until exudative MNV occurred. Systematic grading was performed at baseline and change in drusen area and onset of exudative MNV recorded over the period of follow up. A total of 75 eyes from 75 patients (29 with pachydrusen and 46 with soft drusen) were included. There was no difference in the rate of progression to exudative MNV in the soft and pachydrusen groups (13.3% versus 24.1%, p = 0.38). Pachydrusen, as compared to soft drusen, was associated with polypoidal choroidal vasculopathy subtype (85.7% versus 16.7%, p < 0.01) and the location of exudation was co-localised with soft drusen but not with pachydrusen. There was a higher rate of increase in soft drusen area compared to pachydrusen area (27.7 ± 31.9%/year versus 8.7 ± 12.4%/year respectively, p < 0.01). We found no difference in the proportion of eyes that developed exudative MNV in this study however characterisation of drusen evolution patterns revealed a strong association with exudative MNV subtype.

Clustering of eyes with age-related macular degeneration or pachychoroid spectrum diseases based on choroidal thickness profile

Choroidal changes have been suggested to be involved in the pathophysiology of both age-related macular degeneration (AMD) and pachychoroid spectrum diseases (PSD). To find out the choroidal characteristics of each disease groups, various groups of AMD and PSD were classified into several clusters according to choroidal profiles based on subfoveal choroidal thickness (CT), peripapillary CT, the ratio of subfoveal CT to peripapillary CT and age. We retrospectively analyzed 661 eyes, including 190 normal controls and 471 with AMD or PSDs. In the AMD groups, eyes with soft drusen or reticular pseudodrusen were belonged to the same cluster as those with classic exudative AMD (all p < 0.001). However, eyes with pachydrusen were not clustered with eyes from other AMD groups; instead, they were classified in the same cluster as eyes from the PSD group (all p < 0.001). In the PSD group, eyes with pachychoroid neovasculopathy were grouped in the same cluster of those with polypoidal choroidal vasculopathy (p < 0.001). The cluster analysis based on the CT profiles, including subfoveal CT, peripapillary CT, and their ratio, revealed a clustering pattern of eyes with AMD and PSDs. These findings support the suggestion that pachydrusen has the common pathogenesis as PSD.

Drusen and pachydrusen: the definition, pathogenesis, and clinical significance

The pachychoroid disease spectrum encompasses seven major retinal conditions including central serous chorioretinopathy (CSC), polypoidal choroidal vasculopathy (PCV), and pachychoroid neovasculopathy or type I macular neovascularisation (MNV) secondary to chronic persistent thickening and dysfunction of the choroidal vasculature. Drusen are focal yellow-white deposits of extracellular debris, which consist of complement proteins, esterified and nonesterified cholesterol, apolipoproteins, carbohydrates, and trace elements, above the retinal pigment epithelium (RPE) or between the RPE and Bruch's membrane. Although drusen are an essential disease precursor of advanced age-related macular degeneration (AMD), a new entity "pachydrusen" has been identified to be associated with some of the enitites that constitute the pachychoroid spectrum. It remains to be determined what the exact differences are between soft drusen, pseudodrusen, and pachydrusen in terms of phenotype, genotype, and pathogenesis. Improving our knowledge in these areas will inevitably improve our understanding of their clinical significance especially as in disease prediction in AMD and the pachychroid spectrum disorders. It remains controversial whether PCV is a subtype of AMD. Understanding the pathogenesis of different types of drusen may also help in addressing if phenotype and/or genotype of type 1 MNV associated with pachychoroid are similar to type 1 MNV related to AMD. Furthermore, because pachydrusen links two pachychoroid diseases, CSC and PCV, it is also of great interest to investigate if CSC is an early stage or a predictor of PCV in future research. In this review, we share our experience in clinical practice and the latest published evidence-based literature to emphasize the differences and similarities in morphology, pathogenesis, and clinical significance of drusen and pachydrusen, a new member of the pachychoroid spectrum disorders.

Low incidence of pachydrusen in central serous chorioretinopathy in an Indian cohort

Purpose:

The aim of this study is to report the prevalence, clinical and swept-source optical coherence tomography (SS-OCT) characteristics of pachydrusen in eyes with central serous chorioretinopathy (CSCR) and their fellow eyes.

Methods:

A total of 264 eyes of 132 patients with a diagnosis of CSCR (acute/persistent/recurrent/chronic/inactive) in atleast one eye, were analyzed in this retrospective, cross-sectional study. SS-OCT parameters including choroidal thickness (CT), large choroidal vessel layer thickness (LCVT) at fovea and the site of pachydrusen were recorded. Paired t test and analysis of variance (ANOVA) was used to compare CT in eyes with CSCR (subfoveal and site of pachydrusen) and multiple groups respectively.

Results:

The mean age of the study patients was 42.9 ± 9.5 years with 119 males (90.15%). Bilateral CSCR was present in 31 patients. Nine eyes (chronic, 4; persistent, 2; and inactive/resolved CSCR, 3) showed presence of pachydrusen with an overall prevalence of 6.82% (9 eyes of 9 patients out of 132 patients). There was no significant difference of subfoveal CT (SFCT) in eyes with CSCR (422.4 ± 107.8 μ) vs fellow eyes (407.0 ± 96.5 μ) and eyes with CSCR associated with pachydrusen (413.7 ± 101.5 μ) vs fellow eyes of CSCR eyes with pachydrusen (431.6 ± 188.8 μ) (P = 0.71). LCVT as a percentage of CT was higher at the site of pachydrusen compared to SFCT (69.8% vs. 50.8%).

Conclusion:

CSCR can be associated with pachydrusen with a lower prevalence rate than previously reported. Whether the thickened large choroidal vessels at site of pachydrusen play any role in formation in pachydrusen needs further evaluation.

Deep phenotype unsupervised machine learning revealed the significance of pachychoroid features in etiology and visual prognosis of age-related macular degeneration

Unsupervised machine learning has received increased attention in clinical research because it allows researchers to identify novel and objective viewpoints for diseases with complex clinical characteristics. In this study, we applied a deep phenotyping method to classify Japanese patients with age-related macular degeneration (AMD), the leading cause of blindness in developed countries, showing high phenotypic heterogeneity. By applying unsupervised deep phenotype clustering, patients with AMD were classified into two groups. One of the groups had typical AMD features, whereas the other one showed the pachychoroid-related features that were recently identified as a potentially important factor in AMD pathogenesis. Based on these results, a scoring system for classification was established; a higher score was significantly associated with a rapid improvement in visual acuity after specific treatment. This needs to be validated in other datasets in the future. In conclusion, the current study demonstrates the usefulness of unsupervised classification and provides important knowledge for future AMD studies.

Pachychoroid: current concepts on clinical features and pathogenesis

PURPOSE

The term "pachychoroid" refers to a newly described phenotype in which functional and structural choroidal changes are thought to play a key pathogenic role in a spectrum of related retinal disorders. A more detailed understanding of how the choroid is involved within this spectrum and a better knowledge of the most relevant clinical signs of the pachychoroid phenotype are important to differentiate these disorders from other retinal conditions. Our objectives are to provide a literature review of pachychoroid and the commonalities that may be present across pathologies included in the spectrum, and to provide details on the examination, monitoring, and management of these disorders.

METHODS

We searched the PubMed web platform to identify relevant studies using the following keywords: pachychoroid, pachychoroid pigment epitheliopathy, pachychoroid neovasculopathy, aneurysmal type 1 neovascularization, focal choroidal excavation, peripapillary pachychoroid syndrome, vasculopathy pachysclera, pachychoroid geographic atrophy, and pachydrusen. We selected 157 publications and identified the most important features related to pachychoroid.

RESULTS

The presence of hypertrophic or congested vessels in the choroid, not thickened choroid per se, under an area of reduced or absent choriocapillaris in the posterior pole seems to be the most salient feature of pachychoroid. However, other qualitative/quantitative features are needed to differentiate the uncomplicated pachychoroid from the pathological pachychoroid clinical spectrum, which may be associated with exudation, neovascularization, and/or retinal pigment epithelium and photoreceptor atrophy.

CONCLUSIONS

The most salient feature of pachychoroid appears to be the presence of large vessels under an area of reduced or absent choriocapillaris. Knowledge of the features and pathogenesis of the different disorders in the pachychoroid spectrum may assist in the management of patients.

Response to photodynamic therapy combined with intravitreal aflibercept for polypoidal choroidal vasculopathy depending on fellow-eye condition:2-year results

We investigated whether response to photodynamic therapy (PDT) with intravitreal aflibercept injection (IAI) for polypoidal choroidal vasculopathy (PCV) differs depending on fellow eye condition. A retrospective review was conducted for consecutive 60 eyes with PCV treated with PDT combined with IAI as well as 2-years of follow-up data. Fellow eyes were divided into 4 groups; Group 0: no drusen, Group 1; pachydrusen, Group 2; soft drusen, Group 3: PCV/fibrovascular scarring. Best-corrected visual acuity improved at 24-months irrespective of groups and there were no significant differences in visual improvement among treated eyes among the 4 groups. Within 2-years, 35 (58.3%) required the retreatment. The need for retreatment including additional injection and the combination therapy was significantly less in Group 1(12.5%) compared to the others (P = 0.0038) and mean number of additional IAI was also less in Group 1 compared to the others (P = 0.017). The retreatment-free period from the initial combination therapy was longest in Group 1 (23.6±1.1 months) (P = 0.0055, Group 0: 19.1±6.9, Group 2: 12.8±7.9, Group 3: 11.5±9.9). The need for retreatment was significantly different according to fellow-eye condition. Among PCV patients, pachydrusen in fellow eyes appear to be a predictive characteristic for a decreased treatment burden at 2 years.

Imaging the Choroid: From Indocyanine Green Angiography to Optical Coherence Tomography Angiography

The choroid is the vascular structure nourishing the retinal pigment epithelium and the outer retina and it plays a key role in the homeostasis of the eye both under physiological and pathological conditions. In the last 20 years we have moved from "guessing" what was happening beyond the retinal pigment epithelium to actually visualize structural and functional changes of the choroid in vivo noninvasively. In this review we describe the state of the art of choroidal imaging, focusing on the multiple techniques available in the clinical and research setting including indocyanine green angiography, labeled-cells angiographies, optical coherence tomography (OCT), enhanced depth imaging, swept source OCT, and OCT angiography. In the first section of the article, we describe their main applications and the basic principles to interpret the imaging results. Increasing evidence suggests that the choroid is much more involved than we used to think in many pathological conditions from uveitis to intraocular tumors, from vascular diseases to age-related macular degeneration. All clinicians should hence know which is the most appropriate imaging investigation to explore the choroid in the disease they are dealing with and how to interpret the results. For this reason the second section of this review summarizes the best imaging approach and the most common findings visible on choroidal imaging in different diseases of the eye.

Characteristics of Pachychoroid Diseases and Age-Related Macular Degeneration: Multimodal Imaging and Genetic Backgrounds

The emergence of pachychoroid disease is changing the concept of age-related macular degeneration (AMD). The concept of pachychoroid diseases was developed through clinical observation of multimodal images of eyes with AMD and central serous chorioretinopathy; however, recent genetic studies have provided a proof of concept for pachychoroid spectrum disease, which should be differentiated from drusen-driven AMD. The genetic confirmation of pachychoroid concept further provides novel viewpoints to decode previously reported findings, which facilitates an understanding of the true nature of pachychoroid diseases and AMD. The purpose of this review was to elucidate the relationship between pachychoroid diseases and AMD by interpreting previous findings on pachychoroid diseases and AMD from the novel viewpoints of genetic associations. We confirmed that previous genetic studies supported the concept of pachychoroid diseases. From a genetic viewpoint, the presence of thick choroid and the presence of choroidal vascular hyperpermeability were important characteristics of pachychoroid spectrum diseases. Previous studies have also suggested the classification of polypoidal choroidal vasculopathy (PCV) into two subtypes, pachychoroid neovasculopathy and drusen-driven PCV. Genetic viewpoints will be beneficial to rearrange subtypes of drusen-driven AMD and pachychoroid spectrum diseases. Further genetic studies are needed to investigate pachyvessels, pachydrusen and the significance of polypoidal lesions in pachychoroid neovasculopathy and drusen-driven AMD/PCV.

Pachychoroid disease: a new perspective on exudative maculopathy

BACKGROUND

Pachychoroid, or the structural and functional abnormalities of the choroid, is one of the most important causes of exudative maculopathies. The purpose of this article is to review the current definitions of pachychoroid and their potential consequences. Most publications are from Asian countries. Although no consensus diagnosis has been reached, pachychoroid is defined by thickened choroid and choroidal vascular hyperpermeability, pachyvessels with inner choroidal attenuation; it is closely linked to pachydrusen. Although some studies suggest choroidal congestion may play a role in its pathogenesis, the exact causes of this condition are still unknown. Pachychoroid is associated with exudative maculopathies including central serous chorioretinopathy, pachychoroid neovasculopathy and polypoidal choroidal vasculopathy (PCV). It is widely accepted that macular neovascular membranes may develop secondary to pachychoroid. Recent clinical observations illustrate the importance of pachychoroid in the etiology of macular neovascularization including neovascular age-related macular degeneration (nAMD).

CONCLUSION

Pachychoroid is an important cause of exudative maculopathies. Both drusen and pachychoroid are increasingly recognized as important causes of macular neovascularization, and eyes formally categorized as typical nAMD or PCV can be further sub-categorized based on the presence or absence of pachychoroid and drusen. There is a need to develop a consensus definition, which will greatly enhance our understanding of pachychoroid and facilitate the development of individual interventions in pachychoroid diseases.

Polypoidal Choroidal Vasculopathy in Congolese Patients

Purpose

Polypoidal choroidal vasculopathy (PCV) is a visually debilitating disease that mostly affects people of African and Asian heritage. Indocyanine green angiography (ICGA) is the recommended exploratory method for definitive diagnosis. The disease has been extensively described in Asians and Caucasians, but not in Africans. This study was conducted to document the clinical presentation and optical coherence tomography features of polypoidal choroidal vasculopathy (PCV) in Congolese patients.

Methods

A prospective case series of patients with PCV was performed between January 2017 and June 2019. Routine ocular examination was performed including best corrected visual acuity measurement, slit-lamp examination, dilated direct fundoscopy, and spectral domain optical coherence tomography (OCT). The diagnosis was based on a combination of clinical and OCT signs.

Results

Fourteen patients were diagnosed with PCV during this period. The average age was 64.7 ± 6.9 years. There were 8 females. Ten (71.4%) patients had systemic hypertension. Most patients (n = 9, 64.3%) had bilateral involvement. Blurred vision was the most common complaint (71.4%). The main clinical presentation was subretinal exudates, seen in 19 (82.6%) eyes of 11 (78.6%) patients and subretinal hemorrhage in 10 (43.5%) eyes. Macular localization was found in 16 eyes (69.5%) of 12 (85.7%) patients. Drusen were observed in 35.7% of the patients. On OCT imaging, thumb-like pigment epithelial detachment and subretinal exudation were the most frequent features, observed in 92.9% and 71.4% of the patients, respectively.

Conclusions

PCV in Congolese patients showed features that are more similar to those observed in Caucasians. In this setting where indocyanine green angiography is not available, OCT facilitates the diagnosis of PCV.

Neovascularization in Fellow Eye of Unilateral Neovascular Age-related Macular Degeneration According to Different Drusen Types

PURPOSE

To investigate the incidence of fellow eye (FE) neovascular age-related macular degeneration (nAMD) in patients with unilateral nAMD according to FE drusen type.

DESIGN

Retrospective cohort study.

METHODS

Between January 2013 and June 2016, 434 consecutive patients with naïve nAMD were enrolled. We selected 280 eligible patients with treatment-naïve, unilateral nAMD for analysis (280/280 = 100% patients were followed up at 2 years; 50/280 = 17.9% patients were followed up at 5 years). The incidence and hazard ratios (HR) of FE nAMD according to age, sex, choroidal thickness, nAMD subtype, and drusen type were analyzed.

RESULTS

The 5-year incidence of FE nAMD was 20.9%. The incidences of the soft plus subretinal drusenoid deposits (SDD), soft drusen only, and SDD only groups were 76.4%, 46.2%, and 25.7%, respectively; they were significantly higher than the no drusen group (vs 3.6%; P < .001, P < .001, P < .001). There was no significant difference between the pachydrusen and no drusen groups (7.1% vs 3.6%; P = .101). The multivariate Cox regression hazard model revealed older age (HR, 1.053; P = .031) and drusen type were significant (P = .001). Compared with the no drusen group, the soft drusen plus SDD, soft drusen only, and SDD groups showed an HR of 18.460 (P = .001), 8.302 (P = .015), and 5.465 (P = .082), respectively. Pachydrusen was not shown to be a significant risk factor compared to the no drusen group (HR, 2.417; P = .281).

CONCLUSION

The incidence of FE nAMD was significantly different with respect to drusen type. Soft drusen plus SDD had the highest risk of neovascular AMD, followed by soft drusen only and SDD only.

Five-Year Follow-Up of Unaffected Fellow Eyes in Patients with Polypoidal Choroidal Vasculopathy

PURPOSE

To evaluate the incidence and risk factors of neovascular age-related macular degeneration (nAMD) including polypoidal choroidal vasculopathy (PCV) or any type of choroidal neovascularization (CNV) in fellow eyes of unilateral PCV.

METHODS

This retrospective study included 48 patients with unilateral PCV. For the initial PCV diagnosis, optical coherence tomography and indocyanine green angiography were performed, and patients with and without neovascularization were compared.

RESULTS

Of 48 fellow eyes, 10 (20.8%) had drusen, 9 (18.8%) had retinal pigment epitheliopathy, 9 (18.8%) had irregular retinal pigment epithelium (RPE) elevation, 13 (27.1%) had choroidal vascular dilation, 12 (25%) had choroidal vascular hyperpermeability, and 9 (18.8%) had branching vascular network (BVN) at baseline. The development of nAMD was noted in 8 eyes (17%). The subfoveal choroidal thickness (p = 0.001), irregular RPE elevation (p < 0.001), choroidal vascular dilation (p < 0.001), choroidal vascular hyperpermeability (p < 0.001), and BVN (p < 0.001) in fellow eyes were significantly correlated with development of PCV. After multivariate analysis, BVN (p = 0.045, odds ratio = 24.66) in the fellow eye was the only significant risk factor for the development of nAMD.

CONCLUSIONS

PCV or CNV developed in 17% of fellow eyes during the 5 years. Unilateral PCV with contralateral BVN requires careful monitoring for future development of PCV or CNV in fellow eyes.

Clinical and genetic characteristics of pachydrusen in patients with exudative age-related macular degeneration

We investigated the clinical and genetic characteristics of patients with unilateral exudative age-related macular degeneration (AMD), including typical AMD, polypoidal choroidal vasculopathy, and retinal angiomatous proliferation, in whom pachydrusen was seen. Patients with unilateral exudative AMD with at least a 12-month follow-up period were included. According to the fellow eye condition, 327 consecutive patients were classified into 4 groups: Group 0: no drusen (42.8%), Group 1: pachydrusen (12.2%), Group 2: soft drusen (30.3%), Group 3: pseudodrusen with or without soft drusen (14.7%). Development of exudative AMD in the fellow eye was retrospectively studied for a 60-month period and this inter-group comparisons were performed. Genotyping was performed for ARMS2 A69S and CFH I62V. The thickness of the choroid in the fellow eyes increased significantly in Group 1 than in other groups (all P < 1.0 × 10⁻⁷). The development of exudative AMD in the fellow eye was significantly less frequent in Group 1 than in Groups 2 or 3 (P = 0.022 and 0.0015, respectively). Risk allele frequency of ARMS2 A69S was significantly lower in Group 1 than in Group 2 and 3 (all P < 1.0 × 10⁻⁴). Patients with pachydrusen have genetic and clinical characteristics distinct from those of soft drusen and pseudodrusen.