Choroidal Changes Associated With Subretinal Drusenoid Deposits in Age-related Macular Degeneration Using Swept-source Optical Coherence Tomography

Reticular Pseudodrusen: Impact of Their Presence and Extent on Local Rod Function in Age-Related Macular Degeneration

Purpose

To understand the spatial relationship between local rod-mediated visual function and reticular pseudodrusen (RPD) in eyes with large drusen.

Design

Retrospective cross-sectional study.

Participants

One eye with large drusen (>125 μm) each from 91 individuals with intermediate age-related macular degeneration, with and without RPD.

Methods

All participants underwent dark adaptation testing using a dark-adapted chromatic perimeter, where visual sensitivities were measured over 30 minutes of dark adaptation after photobleach. The rod intercept time (RIT; a measure of dynamic rod function) and pointwise sensitivity difference (PWSD; a relative measure of rod- compared with cone-mediated function) was determined at multiple retinal locations, and their association with the overall (central 20° × 20° region) and local (2° diameter region centered on the location tested) extent of RPD and drusen (quantified using multimodal imaging) was examined.

Main Outcome Measures

Association between overall and local extent of RPD and drusen with RIT and PWSD at each retinal location tested.

Results

In a multivariable analysis, delayed RIT was associated with an increasing overall (P < 0.001), but not local (P = 0.884), extent of RPD. In contrast, the increasing local (P < 0.001), but not overall (P = 0.475), extent of drusen was associated with delayed RIT. Furthermore, only an increasing overall extent of RPD (P < 0.001) was associated with reduced PWSD (or worse rod compared with cone function), but not the local extent of RPD and drusen, or overall extent of drusen (P ≥ 0.344).

Conclusions

Local rod-mediated function was associated with the overall, rather than local, extent of RPD in eyes with large drusen, suggesting that there may be widespread pathologic changes in eyes with RPD that account for this.

Financial Disclosures

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

An overview of retinal light damage models for preclinical studies on age-related macular degeneration: identifying molecular hallmarks and therapeutic targets

Age-related macular degeneration (AMD) is a complex, multifactorial disease leading to progressive and irreversible retinal degeneration, whose pathogenesis has not been fully elucidated yet. Due to the complexity and to the multiple features of the disease, many efforts have been made to develop animal models which faithfully reproduce the overall AMD hallmarks or that are able to mimic the different AMD stages. In this context, light damage (LD) rodent models of AMD represent a suitable and reliable approach to mimic the different AMD forms (dry, wet and geographic atrophy) while maintaining the time-dependent progression of the disease. In this review, we comprehensively reported how the LD paradigms reproduce the main features of human AMD. We discuss the capability of these models to broaden the knowledge in AMD research, with a focus on the mechanisms and the molecular hallmarks underlying the pathogenesis of the disease. We also critically revise the remaining challenges and future directions for the use of LD models.

Quantifying cardiac dysfunction and valvular heart disease associated with subretinal drusenoid deposits in age-related macular degeneration

BACKGROUND/AIMS

Demonstrate through objective multidisciplinary imaging that subretinal drusenoid deposits (SDDs) in age-related macular degeneration (AMD) are linked to both coexistent valvular heart disease (VHD) and reduced systemic perfusion via cardiac index (CI).

METHODS

Post-hoc analysis of cross-sectional study. 200 intermediate AMD (iAMD) subjects were assigned by masked readers to two groups: SDD (with or without drusen) and drusen (only) based on multimodal ophthalmic imaging. 65 transthoracic echocardiograms (TTEs) reports were available for cardiologist evaluation of VHD severity of the four cardiac valves and the presences of precursor lesions of aortic sclerosis (ASc) and mitral annular calcification (MAC). Necessary parameters to calculate CI were also obtained. Univariate testing was performed using Fisher's Exact test and t-test.

RESULTS

82.6% (19/23) of the iAMD subjects with at least one moderate/severe VHD had concurrent SDDs (p = 0.0040). All cases of aortic regurgitation (6/6, p = 0.0370) and mitral regurgitation (13/13, p = 0.0004) were found with coexisting SDDs. Stenotic VHD was not significantly associated with SDDs, however 70.7% of subjects with ASc (29/41, p = 0.0108) and 76.0% of subjects with MAC (19/25, 0.0377) had coexisting SDDs. CI was available in 48 subjects and was significantly below normal levels in the SDD cohort (mean CI SDD 1.95 ± 0.60 L/min/m2, non-SDD 2.71 ± 0.73 L/min/m2, p = 0.0004).

CONCLUSIONS

Several specific VHDs have been found associated with the SDD form of AMD. Decreased systemic perfusion as measured by CI was also associated with SDDs, which supports a perfusion hypothesis of SDD pathogenesis. Further research is warranted to understand the relationship between cardiovascular disease and SDDs.

Neovascular age-related macular degeneration: disease pathogenesis and current state of molecular biomarkers predicting treatment response-a scoping review

Age-related macular degeneration is a major cause of blindness, and the development of anti-vascular endothelial growth factor (VEGF) intravitreal treatments has revolutionised the management of the disease. At the same time, new challenges and unmet needs arose due to the limitations of the current therapeutic options. Neovascularisation development during the course of the disease has a complex pathogenetic mechanism, and several biomarkers and their association with treatment outcomes have been investigated. We reviewed the relevant literature about neovascularisation development and biomarkers related to response to treatment. Improving our knowledge on the field can improve patient outcomes and offer personalised care.

Two potentially distinct pathways to geographic atrophy in age-related macular degeneration characterized by quantitative fundus autofluorescence

BACKGROUND/AIMS

To demonstrate two distinct pathways to geographic atrophy (GA) that originate from soft drusen/ pigment epithelial detachments (PEDs) and subretinal drusenoid deposits (SDDs), respectively, and are characterized by their final quantitative autofluorescence (qAF) levels.

METHODS

23 eyes of 18 patients with GA underwent spectral-domain optical coherence tomography (SD-OCT) and qAF imaging on the qAF-ready Heidelberg Spectralis. 52 GA Regions-of-interest (ROIs), or clusters of adjacent lesions, were selected, and the ROIs were divided into groups by the dominant iAMD precursors on prior serial tracked SD-OCT scans. Mean qAF values and structural SD-OCT findings of groups were compared.

RESULTS

Group 1 lesions (soft drusen/PED precursors, 18/52) were isolated, with lower mean qAF (35.88 ± 12.75 units); group 3 lesions (SDD precursors, 12/52) were multilobular, with significantly higher mean qAF (71.62 ± 12.12 units, p < 0.05). Group 2 lesions, (mixed precursors, 22/52) had intermediate mean qAF (58.13 ± 67.92 units). Significantly greater prevalence of split RPE/ Bruch's membrane complex in SDD-associated GA, suggesting basal laminar deposit (BLamD), than in drusen-associated lesions was the major structural difference.

CONCLUSION

Quantitative autofluorescence (qAF) of GA lesions may reflect two distinct pathogenic pathways and structural outcomes, originating from soft drusen/PED and subretinal drusenoid deposits (SDDs), with the final qAF values lower or higher, respectively. Basal laminar deposit specifically in and adjacent to SDD-associated lesions may account for their greater autofluorescence. The potential importance of this paradigm is that it could direct, simplify and facilitate research on geographic atrophy by dividing the disease into two components that may be studied separately.

Subretinal drusenoid deposits as a biomarker of age-related macular degeneration progression via reduction of the choroidal vascularity index

BACKGROUND/OBJECTIVES

This study aimed to analyse the role of the choroid in early age-related macular degeneration (AMD) by analysing choroidal vascularity index (CVI) in pure cohorts of patients with subretinal drusenoid deposits (SDD) or conventional drusen (CD).

SUBJECTS/METHODS

This was an observational cross-sectional study. Comprehensive ophthalmologic examination and multimodal imaging including fundus photography, autofluorescence, near infrared reflectance, and spectral domain optical coherence tomography (SDOCT) was performed. CVI processing was performed on a foveal horizontal SDOCT scan with binarization using Image J Image software and calculated as the ratio between luminal area (LA) and total area (TA).

RESULTS

Sixty-nine eyes of 69 participants were included; 23 eyes with SDD alone, 22 eyes with CD alone, and 24 control eyes of healthy age-matched subjects. CVI was significantly reduced in the SDD and CD group compared to controls (p = 0.0001). Post-hoc analysis revealed a significant reduction of CVI in the SDD versus the control group (p = 0.0002), in the CD versus the control group (p = 0.001), and in the SDD versus the CD group (p = 0.006). Covariance analysis showed a significant difference of LA (p = 0.033) but no significant difference of TA (p = 0.106) between the three groups. Direct comparison between CD and SDD showed a significant reduction of LA and TA in the SDD group.

CONCLUSIONS

CVI may have prognostic implications in early AMD. SDD is a biomarker of AMD progression and the mechanism for this could be via reduction of the CVI.

Impact of Reticular Pseudodrusen on Choriocapillaris Flow Deficits and Choroidal Structure on Optical Coherence Tomography Angiography

PURPOSE

To examine the impact of reticular pseudodrusen (RPD) on choriocapillaris blood flow and choroidal structure in individuals with intermediate age-related macular degeneration (AMD).

METHODS

Individuals with bilateral large drusen underwent optical coherence tomography (OCT), color fundus photography, near-infrared reflectance, and fundus autofluorescence imaging to determine the presence of RPD. These participants also underwent swept-source OCT angiography (SS-OCTA) imaging to determine (1) choriocapillaris flow deficit (FD) parameters, including the percentage, mean size, and number of FDs present; and (2) choroidal structural parameters, including mean choroidal thickness and choroidal vascularity index. Differences in these parameters between eyes with and without coexistent RPD were examined with and without adjustment for potential key confounders such as drusen volume from the SS-OCTA scans and age.

RESULTS

This study included 102 eyes from 51 individuals with bilateral large drusen, and the analyses showed that there were no significant differences in the choriocapillaris FD parameters (P ≥ 0.062 for all) and choroidal structural parameters (P ≥ 0.059 for all), with or without adjustment for potential confounders in this cohort. However, the percentage of FDs and the mean FD size were both significantly greater with increasing drusen volume (P ≤ 0.038 for both).

CONCLUSIONS

The coexistence of RPD in eyes of individuals with intermediate AMD was not associated with significant impairments in choriocapillaris blood flow and choroidal vascular structural changes, with or without adjustment for key confounders. These findings suggest that macular changes in these vascular parameters may not be associated with the presence of RPD.

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.

Lipid metabolism and retinal diseases

PURPOSE

The retina has enormous lipids demands and must meet those needs. Retinal lipid homeostasis appears to be based on the symbiosis between neurons, Müller glial cells (MGC), and retinal pigment epithelium (RPE) cells, which can be impacted in several retinal diseases. The current research challenge is to better understand lipid-related mechanisms involved in retinal diseases, such as age-related macular degeneration (AMD) and glaucoma.

RESULTS

In a first axis, in vitro and focus on Müller glial cell, we aimed to characterize whether the 24S-hydroxycholesterol (24S-OHC), an overexpressed end-product of cholesterol elimination pathway in neural tissue and likely produced by suffering retinal ganglion cells in glaucoma, may modulate MGC membrane organization, such as lipid rafts, to trigger cellular signalling pathways related to retinal gliosis. We have found that lipid composition appears to be a key factor of membrane architecture, especially for lipid raft microdomain formation, in MGC. However, 24S-OHC did not appear to trigger retinal gliosis via the modulation of lipid or protein composition within lipid rafts microdomains. This study provided a better understanding of the complex mechanisms involved in the pathophysiology of glaucoma. On a second clinical ax, we focused on the lipid-related mechanisms involved in the dysfunction of aging RPE and the appearance of drusenoid deposits in AMD. Using the Montrachet population-based study, we intend to report the frequency of reticular pseudodrusen (RPD) and its ocular and systemic risk factors, particularly related to lipid metabolisms, such as plasma lipoprotein levels, carotenoids levels, and lipid-lowering drug intake. Our study showed that RPD was less common in subjects taking lipid-lowering drugs. Lipid-lowering drugs, such as statins, may reduce the risk of RPD through their effect on the production and function of lipoproteins. This observation highlights the potential role of retinal lipid trafficking via lipoproteins between photoreceptors and retinal pigment epithelium cells in RPD formation. Those findings have been complemented with preliminary results on the analysis of plasma fatty acid (FA) profile, a surrogate marker of short-term dietary lipid intake, according to the type of predominant drusenoid deposit, soft drusen or RPD, in age-related maculopathy.

CONCLUSION

Further research on lipid metabolism in retinal diseases is warranted to better understand the pathophysiology of retinal diseases and develop new promising diagnostic, prognostic, and therapeutic tools for our patients.

Reticular pseudodrusen: A critical phenotype in age-related macular degeneration

Reticular pseudodrusen (RPD), or subretinal drusenoid deposits (SDD), refer to distinct lesions that occur in the subretinal space. Over the past three decades, their presence in association with age-related macular degeneration (AMD) has become increasingly recognized, especially as RPD have become more easily distinguished with newer clinical imaging modalities. There is also an increasing appreciation that RPD appear to be a critical AMD phenotype, where understanding their pathogenesis will provide further insights into the processes driving vision loss in AMD. However, key barriers to understanding the current evidence related to the independent impact of RPD include the heterogeneity in defining their presence, and failure to account for the confounding impact of the concurrent presence and severity of AMD pathology. This review thus critically discusses the current evidence on the prevalence and clinical significance of RPD and proposes a clinical imaging definition of RPD that will help move the field forward in gathering further key knowledge about this critical phenotype. It also proposes a putative mechanism for RPD formation and how they may drive progression to vision loss in AMD, through examining current evidence and presenting novel findings from preclinical and clinical studies.

Inner Retinal Layer Thickness Alterations in Early Age Related Macular Degeneration in Eyes with Subretinal Drusenoid Deposits or Conventional Drusen

The purpose of this study was to evaluate central and parafoveal inner retinal layer thickness in patients with subretinal drusenoid deposits (SDD) or conventional drusen (CD). Participants underwent comprehensive ophthalmoscopic examination. Evidence of SDD or CD was evaluated with near infrared reflectance and spectral domain optical coherence tomography. Quantification of subfoveal lesions was made through a qualitative analysis of vertical and horizontal SD-OCT scans centered on the fovea. Inner retinal layer macular thickness measurements were obtained for central circles with 1, 3, and 5 mm diameter. Continuous variables were compared by the analysis of covariance (ANCOVA) with post-hoc Tukey HSD correction for multiple comparison analysis. Fifty-five patients were included in the study; 18 eyes with SDD alone, 19 eyes with CD alone, and 18 eyes of healthy age-matched subjects. Eight eyes with SDD (44%) and 13 eyes with CD (68%) had subfoveal lesions. There was significant reduction in the inner retinal layer thickness in the central 1mm area and in the superior 3 mm area in the SDD and CD group compared to controls. In conclusion the inner retinal layer is thinner in the central macula and in the superior parafovea in eyes.

Biomarkers for Nonexudative Age-Related Macular Degeneration and Relevance for Clinical Trials: A Systematic Review

TOPIC

The purpose of the review was to identify structural, functional, blood-based, and other types of biomarkers for early, intermediate, and late nonexudative stages of age-related macular degeneration (AMD) and summarize the relevant data for proof-of-concept clinical trials.

CLINICAL RELEVANCE

AMD is a leading cause of blindness in the aging population, yet no treatments exist for its most common nonexudative form. There are limited data on the diagnosis and progression of nonexudative AMD compared to neovascular AMD. Our objective was to provide a comprehensive, systematic review of recently published biomarkers (molecular, structural, and functional) for early AMD, intermediate AMD, and geographic atrophy and to evaluate the relevance of these biomarkers for use in future clinical trials.

METHODS

A literature search of PubMed, ScienceDirect, EMBASE, and Web of Science from January 1, 1996 to November 30, 2020 and a patent search were conducted. Search terms included "early AMD," "dry AMD," "intermediate AMD," "biomarkers for nonexudative AMD," "fundus autofluorescence patterns," "color fundus photography," "dark adaptation," and "microperimetry." Articles were assessed for bias and quality with the Mixed-Methods Appraisal Tool. A total of 94 articles were included (61,842 individuals).

RESULTS

Spectral-domain optical coherence tomography was superior at highlighting detailed structural changes in earlier stages of AMD. Fundus autofluorescence patterns were found to be most important in estimating progression of geographic atrophy. Delayed rod intercept time on dark adaptation was the most widely recommended surrogate functional endpoint for early AMD, while retinal sensitivity on microperimetry was most relevant for intermediate AMD. Combinational studies accounting for various patient characteristics and machine/deep-learning approaches were best suited for assessing individualized risk of AMD onset and progression.

CONCLUSION

This systematic review supports the use of structural and functional biomarkers in early AMD and intermediate AMD, which are more reproducible and less invasive than the other classes of biomarkers described. The use of deep learning and combinational algorithms will gain increasing importance in future clinical trials of nonexudative AMD.

CHOROIDAL THICKNESS AND VASCULARITY VARY WITH DISEASE SEVERITY AND SUBRETINAL DRUSENOID DEPOSIT PRESENCE IN NONADVANCED AGE-RELATED MACULAR DEGENERATION

PURPOSE

To investigate how choroidal features vary with age-related macular degeneration (AMD) severity in early-intermediate disease.

METHODS

One hundred fifty-one eyes of 151 participants >50 years with no to intermediate AMD were analyzed with enhanced depth imaging optical coherence tomography. Mean macular choroidal thickness (CT), choroidal vascular thickness (CV), and choroidal vascularity index (CVI) were determined, and statistical associations were calculated.

RESULTS

Decreased CT and CV were associated with increased axial length (+30 and +14 µm/mm, respectively; P < 0.0001 each), whereas decreased CVI was associated with increased age (+0.1%/year; P = 0.004). Compared with eyes with no/early AMD (Group 0), eyes with large drusen without late AMD in the fellow eye (Group 1) showed increased CV and CVI (+22 µm, P = 0.03 and +2.2%, P = 0.02, respectively). However, eyes with large drusen and late AMD in the fellow eye (Group 2) resembled Group 0. Eyes with subretinal drusenoid deposits demonstrated lower mean CT/CV/CVI than Group 0 (-57 µm, P = 0.02; -31 µm, P = 0.02; -3.6%, P = 0.007).

CONCLUSION

Early AMD progression seems associated with biphasic alterations in choroidal dimensions, increasing during early drusen formation but decreasing thereafter. Subretinal drusenoid deposits are independently associated with marked reductions in all choroidal parameters. Changes in choroidal vascular anatomy may drive or reflect the pathobiology of AMD progression.

Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA)

The advent of optical coherence tomography (OCT) revolutionized both clinical assessment and research of vitreoretinal conditions. Since then, extraordinary advances have been made in this imaging technology, including the relatively recent development of swept-source OCT (SS-OCT). SS-OCT enables a fast scan rate and utilizes a tunable swept laser, thus enabling the incorporation of longer wavelengths than conventional spectral-domain devices. These features enable imaging of larger areas with reduced motion artifact, and a better visualization of the choroidal vasculature, respectively. Building on the principles of OCT, swept-source OCT has also been applied to OCT angiography (SS-OCTA), thus enabling a non-invasive in depth-resolved imaging of the retinal and choroidal microvasculature. Despite their advantages, the widespread use of SS-OCT and SS-OCTA remains relatively limited. In this review, we summarize the technical details, advantages and limitations of SS-OCT and SS-OCTA, with a particular emphasis on their relevance for the study of retinal conditions. Additionally, we comprehensively review relevant studies performed to date to the study of retinal health and disease, and highlight current gaps in knowledge and opportunities to take advantage of swept source technology to improve our current understanding of many medical and surgical chorioretinal conditions. We anticipate that SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift to more widespread adoption of new imaging technology to clinical practice.

Macular Functional and Morphological Changes in Intermediate Age-Related Maculopathy

Purpose

The purpose of this study was to evaluate macular preganglionic function and to verify its relationship with retinal and choroidal morphology in patients with intermediate age-related macular degeneration (iAMD) patients.

Methods

All included patients performed multifocal electroretinogram (mfERG) for investigating on macular function from the central 15° of foveal eccentricity, spectral domain optical coherence tomography (SD-OCT) for studying retinal structure, enhanced depth imaging OCT (EDI-OCT) for the measure of choroidal vascularity index (CVI), and OCT-angiography (OCTA) for the evaluation of vessel density (VD) in the superficial and deep capillary plexus, and choriocapillaris (CC) layer.

Results

Twenty-seven patients with iAMD and 20 age-matched control eyes were analyzed. Significantly (P < 0.01) delayed and reduced mfERG responses in the central 0 to 2.5°, paracentral 2.5 to 5°, and overall 0 to 5° areas, as well as increased CVI values in both foveal (1 mm centered to the fovea) and fovea + parafovea areas (3 mm centered to the fovea), increased foveal and parafoveal (annular area of 1-3 mm centered to the fovea) retinal pigment epithelium thickness, and volume and parafoveal outer retinal volume were found in iAMD eyes as compared to controls. Moreover, iAMD eyes showed significantly (P < 0.01) reduced foveal and parafoveal OCTA-VD values in the CC layer when compared to controls. In the iAMD group, not significant (P > 0.01) correlations were found between morphological and functional parameters.

Conclusions

Our findings support a dysfunction of photoreceptors and bipolar cells in both foveal and parafoveal areas in the presence of outer retina, CC, and choroidal structural changes, however, not significantly correlated. The observed enlargement of luminal choroidal area (measured by CVI) is possibly compensatory to CC vascular insufficiency.

Subtype-differentiated impacts of subretinal drusenoid deposits on photoreceptors revealed by adaptive optics scanning laser ophthalmoscopy

PURPOSE

To examine the structure of photoreceptors surrounding two subtypes of subretinal drusenoid deposits (SDD), namely, dot and ribbon SDD, using multimodal imaging including adaptive optics scanning laser ophthalmoscopy (AOSLO) and spectral-domain optical coherence tomography (SD-OCT).

METHODS

Twenty-six eyes of 13 patients with age-related macular degeneration (AMD) and SDD and 16 eyes of 8 subjects in normal chorioretinal health were studied. SDD presence, stage, and subtype were determined using color fundus photographs, infrared reflectance, autofluorescence imaging, and SD-OCT. SDD and surrounding photoreceptors were imaged using AOSLO. The structure of cone photoreceptors and SDD was examined at the baseline and at 2-year follow-up studies in 6 patients.

RESULTS

Dot SDD were identified in 18 eyes of 9 patients and coexisting dot and ribbon SDD were observed in 8 eyes of 4 patients. While a characteristic photoreceptor mosaic was clearly revealed by AOSLO in the area unaffected by lesions in those eyes with dot-only SDD, in unaffected areas adjacent to retinal regions with predominantly ribbon SDD, photoreceptors could no longer be visualized.

CONCLUSION

The invisibility of the photoreceptor mosaic in unaffected areas adjacent to retinal regions with predominantly ribbon SDD suggests degeneration in the outer segment and the interdigitation zone, which impairs the waveguiding ability of the photoreceptors. Our study implies possible differentiation of disease outcome and functional impact in different types of SDD.

Choroidal changes in intermediate age-related macular degeneration patients with drusen or pseudodrusen

Reticular pseudodrusen are associated with a thinner choroid. The aim of our study was to determine the differences in central choroidal thickness and choriocapillaris vascular flow area between eyes with and without reticular pseudodrusen using swept-source optical coherence tomography and swept-source optical coherence tomography angiography. We conducted a retrospective case control study which included 27 eyes from 27 consecutive patients with intermediate age-related macular degeneration and 17 eyes from 17 healthy participants. Complete ophthalmic examinations were carried out including axial length measurements; fundus color retinography; fundus autofluorescence; swept-source optical coherence tomography and swept-source optical coherence tomography angiography; central choroidal thickness and choriocapillaris vascular flow area. Patients were classified as no reticular pseudodrusen, mild reticular pseudodrusen, and severe reticular pseudodrusen. Mean central choroidal thickness in patients exhibiting severe reticular pseudodrusen (110 ± 56 μm) was significantly smaller than in patients with no reticular pseudodrusen (201 ± 76 μm, p < 0.01). Mean choriocapillaris vascular flow area in severe reticular pseudodrusen patients (45.2% ± 3.0%) was also significantly less than in patients with no (47.9% ± 1.6%, p < 0.001) and mild reticular pseudodrusen (47.7% ± 1.0%, p < 0.05). Stepwise multiple regression models confirmed the association of reticular pseudodrusen with central choroidal thickness (p < 0.001) and choriocapillaris vascular flow area (p < 0.01) even after accounting for age, axial length, and refractive error. Soft drusen were not associated with changes in either central choroidal thickness (p = 0.13) nor choriocapillaris vascular flow area (p = 0.29). A significant, positive relationship was found between central choroidal thickness and choriocapillaris vascular flow area (r = 0.44, p = 0.01). Therefore, both central choroidal thickness and choriocapillaris vascular flow area are decreased in eyes with reticular pseudodrusen, as compared to healthy eyes and intermediate age-related macular degeneration eyes not exhibiting reticular pseudodrusen. In addition, central choroidal thickness and choriocapillaris vascular flow area are related, and the reduction of either is directly associated to the severity of reticular pseudodrusen. Further studies are needed to assess the clinical significance of these findings.

Analysis of central macular thickness and choroidal thickness changes in patients with cardiovascular risk factors

OBJECTIVES

The aim of this study was to evaluate central macular thickness (CMT) and choroidal thickness (CT) in the eyes of patients with cardiovascular risk factors (CVRF).

METHODS

A cross-sectional, prospective observational study of 92 patients with CVRF and 21 healthy individuals was conducted. Patients were divided into four groups according to the SCORE system. CMT was evaluated via spectral-domain-optical coherence tomography (SD-OCT). CT at five defined points (subfoveal) [SF] and nasal 500 μm [N0.5] and 1500 μm [N1.5] and 500 μm [T0.5] and temporal 1500 μm [T1.5] from the center of the fovea were measured via enhanced depth imaging (EDI)-OCT.

RESULTS

Mean SFCT at right eyes (RE) and left eyes (LE) were 311.21 ± 77.7 μm and 303.5 ± 49.6 μm, respectively, in patients with mild CVRF (Group 1); 266.5 ± 63.2 μm and 267.0 ± 62.6 μm, respectively, in patients with moderate CVRF (Group 2); 264.7 ± 57.5 μm and 272.3 ± 64.6 μm, respectively, in patients with high CVRF (Group 3); 272.3 ± 64.6 μm and 271.2 ± 63.4 μm, respectively, in patients with very high-risk CVRF (with coronary arterial disease (CAD) (Group 4); and 352.0 ± 74.4 μm and 363.1 ± 89.0 μm, respectively, in the control group. CT (at both eyes) was significantly lower at the subfoveal location in all study groups (P < 0.05), but at nasal and at temporal quadrants of group 3 and group 4 (P < 0.05). No significant difference in CMT was detected between the study and control groups.

CONCLUSIONS

This study demonstrated that CVRF might result in a remarkably thinner CT. Furthermore, subretinal drusenoid deposits were detected at a higher rate in the patients with CVRF than controls, and that rate increased in accordance with the severity of CAD. In the future, changes in CT may be used as a promising novel biomarker as part of the SCORE system prior to the development of CAD.

Subretinal Drusenoid Deposits in the Elderly in a Population-Based Study (the Montrachet Study)

Purpose

The aim of this study was to investigate the prevalence of subretinal drusenoid deposits (SDD) and to identify associated factors in an elderly population.

Methods

The participants of the population-based Montrachet study underwent an exhaustive ophthalmologic examination, including color fundus photography and macular spectral domain-optical coherence tomography (SD-OCT), coupled with infrared reflectance imaging. The presence of SDD and other age-related macular degeneration lesions, according to the European Eye Epidemiology SD-OCT classification of macular diseases, and subfoveal choroidal thickness were recorded. Moreover, the association of SDD and both clinical and demographic factors as well as plasma levels of vitamin E and lutein/zeaxanthin (L/Z) were analyzed.

Results

The mean age of patients was 82.3 ± 3.8 years and 62.7% were female. The prevalence of SDD was 18.1% (n = 205) in the subjects with at least one eye interpretable (n = 1135). In multivariate analysis, SDD was positively associated with increasing age (OR, 4.6; 95% CI, 2.8-7.7; P < 0.001 for subjects aged >85 years), female sex (OR, 1.7; 95% CI, 1.2-2.4; P = 0.005), and plasma L/Z level (OR, 1.2; 95% CI, 1.0-1.5; P = 0.039), and negatively associated with lipid-lowering drugs use (OR, 0.5; 95% CI, 0.3-0.9; P = 0.014 for statin medications) and subfoveal choroidal thickness (OR, 0.8; 95% CI, 0.7-0.9; P = 0.002).

Conclusions

The prevalence of SDD was high in subjects older than 75 years, more frequent in women, and was associated with a thinner choroid. The association with lipid-lowering drugs deserves further investigation.

Iris Thickness and Severity of Neovascular Glaucoma Determined Using Swept-Source Anterior-segment Optical Coherence Tomography

PURPOSE

To investigate the iris thickness (IT) in neovascular glaucoma (NVG) using swept-source anterior-segment optical coherence tomography (ASOCT).

PATIENTS AND METHODS

In this retrospective, clinic-based, comparative study, we enrolled 20 NVG patients [11 with 360-degree angle-closure (AC)-NVG and 9 with NVG without AC] and 14 healthy age-matched controls. Horizontal scanning images of swept-source ASOCT were analyzed using software calipers in temporal and nasal angle areas. ITs at 1 and 2 mm from the pupil edge were measured using ASOCT. The relation between IT and the severity of NVG, the effects of intraocular pressure (IOP), intravitreal antivascular endothelial growth factor (anti-VEGF) injection, and panretinal photocoagulation (PRP) were assessed using linear regression analysis based on the corrected Akaike information criteria index.

RESULTS

The IT was thinner in 360-degree AC-NVG patients, followed by NVG patients without AC and controls (0.33 vs. 0.48 vs. 0.57 mm at 1 mm and 0.31 vs. 0.43 vs. 0.49 mm at 2 mm; P<0.001 by ANOVA). Multiple linear regression analysis revealed that 360-degree AC-NVG patients-NVG patients without AC and controls (coefficient: -0.16), NVG patients without AC-control (-0.13) and underwent PRP (0.23) at 1 mm, 360-degree AC-NVG patients-NVG patients without AC and controls (-0.12), NVG patients without AC-controls (-0.08), underwent PRP (0.16), received anti-VEGF injection (0.05) and IOP (-0.001) at 2 mm were selected predictors to explain IT.

CONCLUSIONS

IT decreases with the progression of the NVG stage and is thinnest in 360-degree AC-NVG patients. Our study suggests a new morphologic feature of NVG.

Effects of Macuprev® Supplementation in Age-Related Macular Degeneration: A Double-Blind Randomized Morpho-Functional Study Along 6 Months of Follow-Up

Background

To evaluate the effects of Macuprev^® supplementation on macular function and structure in intermediate age-related macular degeneration (AMD) along 6 months of follow-up.

Methods

In this double-blind, monocentric, randomized, and prospective study, 30 patients with intermediate AMD were enrolled and randomly divided into two age-similar groups: 15 patients (AMD-M group; mean age 68.50 ± 8.79 years) received 6-month oral daily supplementation with Macuprev^® (Farmaplus Italia s.r.l., Italy, two tablets/day on an empty stomach, before meals; contained in total lutein 20 mg, zeaxanthin 4 mg, N-acetylcysteine 140 mg, bromelain 2500GDU 80 mg, vitamin D₃ 800 IU, vitamin B₁₂ 18 mg, alpha-lipoic acid 140 mg, rutin 157 mg, vitamin C 160 mg, zinc oxide 16 mg, Vaccinium myrtillus 36% anthocyanosides 90 mg, Ganoderma lucidum 600 mg) and 15 patients (AMD-P group; mean age 70.14 ± 9.87) received two tablets of placebo daily on an empty stomach, before meals. A total of 28 eyes, 14 from each AMD group, completed the study. Multifocal electroretinogram (mfERG) and spectral domain-optical coherence tomography (SD-OCT) were assessed at baseline and after 6 months.

Results

At 6-month follow-up, AMD-M eyes showed a significant increase of mfERG response amplitude density (RAD) recorded from the central macular areas (ring 1, 0–2.5°; ring 2, 2.5–5°), whereas non-significant changes of retinal and choroidal SD-OCT parameters were found when values were compared to baseline. Non-significant correlations between functional and structural changes were found. In AMD-P eyes, non-significant differences for each mfERG and SD-OCT parameters were observed at 6 months.

Conclusions

In intermediate AMD, Macuprev^® supplementation increases the function of the macular pre-ganglionic elements, with no associated retinal and choroidal ultra-structural changes.

Trial Registration

ClinicalTrials.gov identifier, NCT03919019.

Funding

Research for this study was financially supported by the Italian Ministry of Health and Fondazione Roma. Article processing charges were funded by Farmaplus Italia s.r.l., Italy.

Computational modeling of retinal hypoxia and photoreceptor degeneration in patients with age-related macular degeneration

Although drusen have long been acknowledged as a primary hallmark of dry age-related macular degeneration (AMD) their role in the disease remains unclear. We hypothesize that drusen accumulation increases the barrier to metabolite transport ultimately resulting in photoreceptor cell death. To investigate this hypothesis, a computational model was developed to evaluate steady-state oxygen distribution in the retina. Optical coherence tomography images from fifteen AMD patients and six control subjects were segmented and translated into 3D in silico representations of retinal morphology. A finite element model was then used to determine the steady-state oxygen distribution throughout the retina for both generic and patient-specific retinal morphology. Oxygen levels were compared to the change in retinal thickness at a later time point to observe possible correlations. The generic finite element model of oxygen concentration in the retina agreed closely with both experimental measurements from literature and clinical observations, including the minimal pathological drusen size identified by AREDS (64 μm). Modeling oxygen distribution in the outer retina of AMD patients showed a substantially stronger correlation between hypoxia and future retinal thinning (Pearson correlation coefficient, r = 0.2162) than between drusen height and retinal thinning (r = 0.0303) indicating the potential value of this physiology-based approach. This study presents proof-of-concept for the potential utility of finite element modeling in evaluating retinal health and also suggests a potential link between transport and AMD pathogenesis. This strategy may prove useful as a prognostic tool for predicting the clinical risk of AMD progression.

OCT Angiography and Cone Photoreceptor Imaging in Geographic Atrophy

Purpose

To compare cone spacing and choriocapillaris (CC) perfusion adjacent to geographic atrophy (GA) in patients with age-related macular degeneration (AMD) and age-similar normal eyes.

Methods

Subjects were imaged using adaptive optics scanning laser ophthalmoscopy (AOSLO), fundus autofluorescence (FAF), and swept-source optical coherence tomography angiography. The GA border was identified using FAF images; CC flow void was analyzed in 1° regions extending from the GA border. A grader masked to CC perfusion selected regions of interest (ROIs) with unambiguous cone mosaics in AOSLO images. At each ROI, cone spacing and CC flow void were converted to Z-scores (standard deviations from the mean of 12 normal eyes aged 50 to 81 years for cone spacing, and 60 normal eyes age 51 to 88 years for CC flow void).

Results

Excluding regions of GA and drusen, CC flow void in eight eyes of six patients with AMD was significantly greater than in four age-similar normal eyes (exact permutation test, P = 0.024). CC flow void was negatively correlated with distance from the GA margin (r = -0.35; 95% confidence interval [CI], -0.53 to -0.12). Increased cone spacing was significantly correlated with CC flow void (r = 0.33; 95% CI, 0.12 to 0.59). Cone spacing was increased in 39% of ROIs, while CC flow void was increased in 96% of ROIs.

Conclusions

In eyes with GA due to AMD, CC hypoperfusion was significantly correlated with, and more extensive than, cone photoreceptor loss. The results suggest that reduced CC perfusion contributes to the development of GA.

Optical coherence tomography evidence of macular ganglion cell-inner plexiform layer thinning in eyes with subretinal drusenoid deposits

BACKGROUND/OBJECTIVES

The purpose of this study was to evaluate macular ganglion cell layer-inner plexiform layer (GCL-IPL) and choroidal thickness in early age-related macular degeneration (AMD) in eyes with subretinal drusenoid deposits (SDD).

SUBJECTS/METHODS

Comprehensive ophthalmological examination was performed. Near infrared reflectance and raster images using enhanced depth imaging were acquired with spectral domain optical coherence tomography. Drusen and SDD were diagnosed based on raster scans and near infrared reflectance. GCL-IPL maps were generated with automated segmentation and choroidal thickness maps were obtained by manually delineating the choroid-scleral boundary.

RESULTS

Forty-eight eyes from 48 patients (mean age 77.5 ± 5.7, range 68-90 years) with a diagnosis of early AMD and 42 eyes of 42 age-matched control subjects (mean age 76.9 ± 5.7, range 67-88 years) were included. Of these, 28 eyes (58.3%) had drusen alone, 4 eyes (8.3%) had SDD alone, and 16 eyes (33.3%) had drusen associated with SDD. Compared with controls, average choroidal thickness was significantly decreased in AMD eyes (P < 0.05). There was no significant difference in choroidal thickness in eyes with SDD with respect to those with drusen alone. GCL-IPL thickness was reduced in an annular pattern at the 3 and 6 mm macular areas in AMD patients with respect to controls (P < 0.05). GCL-IPL thickness at 3 mm was significantly reduced in eyes with SDD with respect to those with drusen alone (P = 0.03).

CONCLUSIONS

The GCL-IPL is reduced in thickness with an annular pattern in early AMD and is significantly thinner in eyes with SDD.

Ultrastructural analysis of submacular choriocapillaris and its transport systems in AMD and aged control eyes

The choriocapillaris is the source of nutrients and oxygen for photoreceptors, which consume more oxygen per gram of tissue than any other cell in the body. The purpose of this study was to evaluate and compare the ultrastructure of the choriocapillaris and its transport systems in patients with and without age-related macular degeneration (AMD). Ultrastructural changes were also evaluated in subjects that were homozygous for polymorphisms in high risk CFH alleles (Pure 1) only or homozygous only for high risk ARMS2/HTRA1 (Pure 10) alleles. Tissue samples were obtained from the macular region of forty male (n = 24) and female (n = 16) donor eyes and prepared for ultrastructural studies with transmission electron microscopy (TEM). The average age of the aged donors was 74 ± 7.2 (n = 30) and the young donors 31.7 ± 11.25 (n = 10). There was no significant difference in average ages between the adult groups. TEM images of the capillaries in the choriocapillaris (CC) were taken at 4,000X and 25,000X and used to measure the area of endothelial cell somas, the number of fenestrations, and area of caveolae within the endothelial cells per length of Bruchs membrane (BrMb). The Student t-test and Wilcoxon sum rank test were used to determine significant differences. There was no significant difference between young subjects and aged controls in any of the morphological criteria assessed. There was a significant decrease in the number of fenestrations/mm of BrMb in atrophic areas of GA eyes (p = 0.007) when compared with aged control eyes. A significant increase was found in the caveolae area as a percent of the endothelial cell soma of capillaries from GA subjects as compared with the controls (p = 0.03). Loss of capillary segments in choriocapillaris was also evident, especially in areas of geographic atrophy and CNV. In eyes from patients with sequence variations, the capillary endothelial cells often appeared degenerative and exhibited atypical fenestrations and pericytes covering the blood vessels. Subjects that were homozygous for polymorphisms in high risk CFH alleles only had more fenestrations/mm of BrMb than subjects that were homozygous only for high risk ARMS2/HTRA1 alleles (p = 0.04), while the latter had greater caveolae area/endothelial cell area than the former (p = 0.007). This study demonstrated an attenuation of CC and a significant decline in the two major transport systems in CC endothelial cells in AMD. This may contribute to drusen deposition, nutrient transport, and vision loss in AMD subjects.

Choroidal thickness and vascular density in macular telangiectasia type 2 using enface swept-source optical coherence tomography

Purpose

To investigate the choroidal thickness (CT) and choroidal vascular densities (CVD) of patients with macular telangiectasia type 2 (MacTel2) and their association with other multimodal imaging features, using swept-source optical coherence tomography (SS-OCT).

Methods

Prospective, cross-sectional study. Consecutive patients with MacTel2 along with controls without any macular disease were included. Fundus photography, confocal blue reflectance, near-infrared reflectance, autofluorescence, fluorescein angiography, spectral domain OCT and SS-OCT were performed. Images were independently analysed by two graders, and CVD was calculated from binarised en face SS-OCT images. CT was obtained from the SS-OCT platform via built-in automated segmentation. Multilevel mixed-effects models were used for statistical analysis.

Results

Thirty-nine eyes of 20 patients with MacTel2 and 29 eyes of 15 control patients were included. Average CT and perifoveal temporal CT did not differ significantly between eyes with MacTel2 and control eyes (p≥0.350), when accounting for confounding factors. Overall and temporal CVD also did not significantly differ between the two groups (p≥0.490).

Conclusion

CT and CVD did not significantly differ between MacTel2 and control eyes in this study using SS-OCT. Even though MacTel2 may include abnormalities involving the choroid, these are likely minor in comparison to the predominant retinal changes.

Visualization of Choriocapillaris and Choroidal Vasculature in Healthy Eyes With En Face Swept-Source Optical Coherence Tomography Versus Angiography

Purpose

To compare the visualization of the choriocapillaris and deeper choroidal vessels in healthy eyes in en face swept-source optical coherence tomography (SS-OCT) versus SS-OCT angiography (SS-OCTA).

Methods

This is a cross-sectional study of consecutive eyes without chorioretinal disease. En face SS-OCT and SS-OCTA images of the choriocapillaris and choroid were assessed for visualization of the vasculature. Choroidal vessel densities (CVD) of the choriocapillaris, inner choroid, midchoroid, and outer choroid were calculated from binarized en face SS-OCT and SS-OCTA images. Paired t-tests and linear regression were used for statistical analysis.

Results

Twenty-seven eyes of 27 patients were included. There was no statistically significant difference between the CVDs of the midchoroid assessed with en face SS-OCT versus SS-OCTA (P = 0.21). However, there were statistically significant differences between the CVDs for the choriocapillaris (P < 0.001), inner choroid (P < 0.001), and outer choroid (P = 0.006). Qualitative analysis revealed incomplete visualization of vessels in the inner choroid and exaggeration of vessel lumens in the outer choroid with SS-OCTA.

Conclusions

Visualization of the choriocapillaris is superior with SS-OCTA, but it has numerous limitations that make visualization of deeper choroidal vessels less reliable when compared with en face SS-OCT. It is important to understand such limitations when using these technologies to study the choroidal vasculature in chorioretinal disease.

Translational Relevance

The presented study of optimal imaging techniques for the choroidal vessels of healthy eyes provides an important foundation for future investigations into the role of the choroidal vasculature in chorioretinal diseases.