Choriocapillaris Impairment Is Associated With Delayed Rod-Mediated Dark Adaptation in Age-Related Macular Degeneration

Dissecting the biological complexity of age-related macular degeneration: Is it one disease, multiple separate diseases, or a spectrum?

Clinicians recognize the heterogeneity of age-related macular degeneration (AMD) in presentation, progression, and treatment response, as well as the challenges in distinguishing it from other macular degenerations. As part of the 2024 Ryan Initiative for Macular Research meeting, a group of clinician-scientists and basic scientists were convened to consider the question of whether AMD should be classified as a single disorder or a spectrum of conditions. To answer this question, we reviewed research on several "dimensions" that constitute AMD risk or pathogenesis: genetics, ancestry, retinal imaging findings, diet and environment, aging, and outer retinal molecular and cellular pathways. The group reached a consensus that AMD represents a heterogeneous collection of disease states arising from the interplay of these dimensions. This heterogeneity can be conceived of as a "cloud" of AMD phenotypes. Defining subtypes within this "cloud" requires longitudinal cohorts of well-genotyped and phenotyped patients who progress from no AMD through late AMD, analyzed by unsupervised learning. Comparing the AMD subtypes that emerge from this analysis, especially -omics data from each subtype, will illuminate biology that is applicable to certain subtypes of AMD patients and molecular pathogenic mechanisms that universally apply to all AMD. This knowledge will, in turn, drive improved drug development.

Photobiomodulation-induced choriocapillaris perfusion enhancement and outer retinal remodelling in intermediate age-related macular degeneration: a promising therapeutic approach with short-term results

PURPOSE

To evaluate the effects of photobiomodulation (PBM) on choriocapillaris (CC) perfusion and drusen volume in patients with intermediate age-related macular degeneration (AMD).

METHODS

In this retrospective pilot study, 30 patients receiving PBM therapy and 30 age-matched controls were analysed. Treatment consisted of 8 sessions over 4 weeks using the EYE-LIGHT® device. Best-corrected visual acuity (BCVA), low luminance visual acuity (LLVA), mean drusen volume (MDV), and CC flow deficit percentage (FD%) were evaluated at baseline and 2-month follow-up.

RESULTS

The PBM group showed significant improvements in BCVA (Δ +3.2 ± 1.4 letters, p = 0.042), reduction in drusen volume (Δ -0.003 ± 0.001 mm³, p = 0.028), and decrease in choriocapillaris FD% (Δ -3.1 ± 1.4%, p = 0.024), while no significant changes were observed in the control group. Changes in choriocapillaris FD% correlated with BCVA improvement (r = -0.54, p = 0.002) and drusen volume reduction (r = 0.35, p = 0.042).

CONCLUSIONS

PBM therapy induces significant choriocapillaris remodelling in intermediate AMD, associated with functional improvement and drusen volume reduction. These findings suggest a potential therapeutic role of PBM in modulating choroidal perfusion in AMD.

Fluorescence Lifetime Imaging Ophthalmoscopy, Vision, and Chorioretinal Asymmetries in Aging and Age-Related Macular Degeneration: ALSTAR2

Purpose

Eyes with age-related macular degeneration (AMD) and some healthy aged eyes exhibit risk-indicating delays in rod-mediated dark adaptation (RMDA) and prolonged long spectral channel (LSC) lifetimes by fluorescence lifetime imaging ophthalmoscopy (FLIO) in the Early Treatment Diabetic Retinopathy Study (ETDRS) outer ring, especially nasally. To learn FLIO's potential for AMD detection, we correlate FLIO to RMDA.

Methods

The ALSTAR2 follow-up cohort underwent FLIO, color fundus photography, two-wavelength autofluorescence (for macular pigment optical density [MPOD]), visual function testing, including RMDA (rod intercept time [RIT]). AMD was staged by the Age-Related Eye Disease Study (AREDS) 9-step at baseline and follow-up. In pseudophakic eyes with high-quality FLIO, mean intensity maps and meridian plots were created. Vision data were analyzed using linear regression and Spearman's r.

Results

Of 155 eyes (155 participants [75 ± 5.0 years; 60.7% female participants]), 67 eyes were healthy, 38 had early (e)AMD, and 50 had intermediate (i)AMD (P = 0.02). LSC lifetimes were longest in iAMD in all ETDRS regions (P < 0.01) and short spectral channel (SSC) lifetimes in inner and outer rings (P < 0.01). The LSC pattern manifested in 65 of 88 AMD eyes and 30 of 67 healthy eyes. Lifetimes were longest on the nasal meridian and shortest on temporal. LSC lifetimes in the inner and outer rings correlated strongly with RIT (r = 0.68). A stable subgroup had short LSC lifetimes and short RIT. SSC correlated weakly with MPOD.

Conclusions

Prolonged lifetimes in AMD exhibit spatial asymmetry, suggesting mechanisms beyond retinal cells and including choroid. Lifetimes correlate with delayed RMDA, potentially indicating risk for AMD onset and early progression. Further research into SSC signal sources is warranted.

Topographic Analysis of Two-Wavelength Autofluorescence Supports Higher Macular Xanthophyll Pigment in AMD Than Aging: ALSTAR2 Baseline

Purpose

To advance metabolic imaging of the high-risk macula lutea by quantifying the topography of macular pigment optical density (MPOD), measured with two-wavelength autofluorescence (2WAF), and quantitative (short-wavelength) autofluorescence (qAF) intensity, which share the same signal source and cross-retinal light path, in aging, early (e), and intermediate (i) age-related macular degeneration (AMD).

Methods

2WAF and qAF images of 384 pseudophakic eyes of 230 persons (mean age, 74.2 ± 5.7 years; 145 female) from ALSTAR2 (AREDS 9-step classification: 170, normal; 118, eAMD; 96 iAMD) were shown as maps (intensity, z-score) and meridian plots. Correlations were determined in Early Treatment Diabetic Retinopathy Study (ETDRS) subfields.

Results

MPOD was higher in the central subfield (P < 0.01) in iAMD compared to eAMD and normal eyes, and qAF was lower in the central subfield and inner ring (both P < 0.01) in AMD compared to normal eyes. MPOD differed along horizontal versus vertical meridians, depending on disease stage. Pixel-level z-score maps and meridian plots showed distinct annuli of alternating levels of MPOD anchored on the foveal center, unrelated to qAF. Across the central subfield, high 2WAF was associated with low qAF in all disease stages (r = -0.47, r = -0.47, r = -0.42; all P < 0.001). In the inner ring, correlations were significant for normal and eAMD only (r = -0.31, P = 0.004 and r = -0.22, P ≤ 0.001, respectively).

Conclusions

New analytics support previously reported higher MPOD in AMD compared to normal eyes, especially central subfield and inner ring. MPOD and qAF differ by disease-stage-related topography and correlations, supporting independent use in metabolic imaging of the macula lutea.

Elevation of Granulocyte Colony Stimulating Factor in Human AMD Donor RPE-Choroid

Purpose

Choroidal inflammation, complement deposition, and accumulation of C-reactive protein (CRP) are involved in age-related macular degeneration (AMD) pathology. The pro-inflammatory signals that regulate immune cell recruitment in the choroid of patients with AMD remain to be determined. We performed cytokine profiling of human AMD and age-matched control donor tissue to identify inflammatory molecules upregulated in AMD tissue.

Methods

Protein was isolated from 25 AMD and 21 control donor RPE/choroid macular punches. Total protein was quantified, and 50 µg assayed for expression of 40 cytokines using an inflammation array. We validated the elevated expression of granulocyte colony stimulating factor (G-CSF) protein by ELISA in a second cohort of 22 control and 26 AMD donors. To identify an AMD associated stressor responsible for upregulating G-CSF we assayed for changes in G-CSF protein secretion in RPE/choroid organ cultures treated with the monomeric (m)CRP, an inflammatory protein elevated in AMD.

Results

Using a multiplex array, we identified elevated G-CSF protein in the choroid of AMD donors compared to age-matched non-AMD controls. Differential expression of G-CSF was confirmed via ELISA in an independent cohort of samples (P = 0.01). The mCRP, which is deposited in AMD choroids, increased G-CSF protein secretion in RPE/choroid organ cultures. Single nuclei RNA sequencing identified choroidal endothelial cells and fibroblasts as the primary cell types responsible for increased G-CSF secretion in response to mCRP. The G-CSF receptor is expressed primarily by choroidal macrophages and dendritic cells and anti-G-CSFR colocalizes with anti-CD45 and anti-CD68 in human donor choroid tissue.

Conclusions

Elevated G-CSF expression in AMD donor tissue as a result of increased levels of mCRP may be involved in immune cell recruitment in AMD contributing to inflammatory stress in the choroid.

Decreased Macular Choriocapillaris Perfusion Correlates with Contrast Sensitivity Function in Dry Age-Related Macular Degeneration

PURPOSE

To investigate the relationships between contrast sensitivity (CS), choriocapillaris perfusion, and other structural OCT biomarkers in dry age-related macular degeneration (AMD).

DESIGN

Cross-sectional, observational study.

PARTICIPANTS

One hundred AMD eyes (22 early, 52 intermediate, and 26 late) from 74 patients and 45 control eyes from 37 age-similar subjects.

METHODS

All participants had visual acuity (VA) assessment, quantitative CS function (qCSF) testing, macular OCT, and 6 × 6-mm swept-source OCT angiography scans on the same day. OCT volumes were analyzed for subretinal drusenoid deposits and hyporeflective drusen cores, and to measure thickness of the outer nuclear layer. OCT angiography scans were utilized to calculate drusen volume and inner choroid flow deficit percentage (IC-FD%), and to measure the area of choroidal hypertransmission defects (HTDs). Inner choroid flow deficit percentage was measured from a 16-μm thick choriocapillaris slab after compensation and binarization with Phansalkar's method. Generalized linear mixed-effects models were used to evaluate the associations between functional and structural variables.

MAIN OUTCOME MEASURES

To explore the associations between qCSF-measured CS, IC-FD%, and various AMD imaging biomarkers.

RESULTS

Age-related macular degeneration exhibited significantly reduced qCSF metrics eyes across all stages compared with controls. Univariate analysis revealed significant associations between various imaging biomarkers, reduced qCSF metrics, and VA in both groups. Multivariate analysis confirmed that higher IC-FD% in the central 5 mm was significantly associated with decreases in all qCSF metrics in AMD eyes (β = -0.74 to -0.25, all P < 0.05), but not with VA (P > 0.05). Outer nuclear layer thickness in the central 3 mm correlated with both VA (β = 2.85, P < 0.001) and several qCSF metrics (β = 0.01-0.90, all P < 0.05), especially in AMD eyes. Further, larger HTD areas were associated with decreased VA (β = -0.89, P < 0.001) and reduced CS at low-intermediate frequencies across AMD stages (β = -0.30 to -0.29, P < 0.001).

CONCLUSIONS

The significant association between IC-FD% in the central 5 mm and qCSF-measured CS reinforces the hypothesis that decreased macular choriocapillaris perfusion contributes to visual function changes in AMD, which are more pronounced in CS than in VA.

FINANCIAL DISCLOSURE(S)

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

Optical coherence tomography angiography of the retina and choroid in systemic diseases

Optical coherence tomography angiography (OCTA) has transformed ocular vascular imaging, revealing microvascular changes linked to various systemic diseases. This review explores its applications in diabetes, hypertension, cardiovascular diseases, and neurodegenerative diseases. While OCTA provides a valuable window into the body's microvasculature, interpreting the findings can be complex. Additionally, challenges exist due to the relative non-specificity of its findings where changes observed in OCTA might not be unique to a specific disease, variations between OCTA machines, the lack of a standardized normative database for comparison, and potential image artifacts. Despite these limitations, OCTA holds immense potential for the future. The review highlights promising advancements like quantitative analysis of OCTA images, integration of artificial intelligence for faster and more accurate interpretation, and multi-modal imaging combining OCTA with other techniques for a more comprehensive characterization of the ocular vasculature. Furthermore, OCTA's potential future role in personalized medicine, enabling tailored treatment plans based on individual OCTA findings, community screening programs for early disease detection, and longitudinal studies tracking disease progression over time is also discussed. In conclusion, OCTA presents a significant opportunity to improve our understanding and management of systemic diseases. Addressing current limitations and pursuing these exciting future directions can solidify OCTA as an indispensable tool for diagnosis, monitoring disease progression, and potentially guiding treatment decisions across various systemic health conditions.

Ghost vessels in the eye: Cell free choriocapillaris domains in atrophic age-related macular degeneration

The choriocapillaris is a dense vascular bed in the inner choroid that supplies the photoreceptor cells and retinal pigment epithelium (RPE). While loss of choriocapillaris density has been described in association with age-related macular degeneration (AMD), whether these changes are primary or secondary to RPE degenerative changes in AMD has been debated. In this study we characterized choriocapillaris loss by quantifying "ghost" vessels in a series of 99 human donor maculae labeled with the UEA-I lectin, and found significant increases in early-intermediate AMD and a greater difference in geographic atrophy in areas with intact RPE. Eyes were genotyped at the CFH Tyr402His locus, and those homozygous for the His allele showed significantly more ghost vessels than those with other genotypes. When only non-AMD eyes were evaluated, His homozygotes had increased ghost vessel density but this trend did not reach statistical significance. These results support the notion that choriocapillaris death often precedes RPE degeneration in AMD and that this loss is an important therapeutic consideration for AMD.

Extent and Topography of Subretinal Drusenoid Deposits Associate With Rod-Mediated Vision in Aging and AMD: ALSTAR2 Baseline

Purpose

In AMD, rod-mediated dark adaptation (RMDA) at 5° eccentricity is slower in eyes with subretinal drusenoid deposits (SDDs) than in eyes without. Here we quantified SDD burden using supervised deep learning for comparison to vision and photoreceptor topography.

Methods

In persons ≥60 years from the Alabama Study on Early Age-Related Macular Degeneration 2, normal, early AMD, and intermediate AMD eyes were classified by the AREDS nine-step system. A convolutional neural network was trained on 55°-wide near-infrared reflectance images for SDD segmentation. Trained graders annotated ground truth (SDD yes/no). Predicted and true datasets agreed (Dice coefficient, 0.92). Inference was manually proofread using optical coherence tomography. The mean SDD area (mm2) was compared among diagnostic groups (linear regression) and to vision (age-adjusted Spearman correlations). Fundus autofluorescence images were used to mask large vessels in SDD maps.

Results

In 428 eyes of 428 persons (normal, 218; early AMD, 120; intermediate AMD, 90), the mean SDD area differed by AMD severity (P < 0.0001): 0.16 ± 0.87 (normal), 2.48 ± 11.23 (early AMD), 11.97 ± 13.33 (intermediate AMD). Greater SDD area was associated with worse RMDA (r = 0.27; P < 0.0001), mesopic (r = -0.13; P = 0.02) and scotopic sensitivity (r = -0.17; P < 0.001). SDD topography peaked at 5° superior, extended beyond the Early Treatment of Diabetic Retinopathy Study grid and optic nerve, then decreased.

Conclusions

SDD area is associated with degraded rod-mediated vision. RMDA 5° (superior retina) probes where SDD is maximal, closer to the foveal center than the rod peak at 3 to 6 mm (10.4°-20.8°) superior and the further eccentric peak of rod:cone ratio. Topographic data imply that factors in addition to rod density influence SDD formation.

Age- and sex- divergent translatomic responses of the mouse retinal pigmented epithelium

Aging is the main risk factor for age-related macular degeneration (AMD), a retinal neurodegenerative disease that leads to irreversible blindness, particularly in people over 60 years old. Retinal pigmented epithelium (RPE) atrophy is an AMD hallmark. Genome-wide chromatin accessibility, DNA methylation, and gene expression studies of AMD and control RPE demonstrate epigenomic/transcriptomic changes occur during AMD onset and progression. However, mechanisms by which molecular alterations of normal aging impair RPE function and contribute to AMD pathogenesis are unclear. Here, we specifically interrogate the RPE translatome with advanced age and across sexes in a novel RPE reporter mouse model. We find differential age- and sex- associated transcript expression with overrepresentation of pathways related to inflammation in the RPE. Concordant with impaired RPE function, the phenotypic changes in the aged translatome suggest that aged RPE becomes immunologically active, in both males and females, with some sex-specific signatures, which supports the need for sex representation for in vivo studies.

Analysis of Choriocapillaris Reperfusion Topography Following Faricimab Treatment for Neovascular Age-Related Macular Degeneration in Therapy-Naïve Patients

INTRODUCTION

To assess changes in choriocapillaris (CC) vascular density surrounding macular neovascularization (MNV) in treatment-naïve age-related macular degeneration (AMD) after faricimab application using optical coherence tomography angiography (OCTA).

METHODS

Twenty-five eyes of 25 treatment-naïve individuals who underwent intravitreal faricimab injections for neovascular AMD (nAMD) with type 1 MNV were included. Spectral-domain optical coherence tomography (SD-OCT) images and en-face swept-source OCTA images were analyzed, and the percentage of CC flow deficit (FD%), FD average area (FDa) and FD number (FDn) in five progressive 20.0-μm-wide concentric rings (R1, R2, R3, R4 and R5) surrounding the dark halo around the MNV were calculated. Image acquisition was carried out prior to the first faricimab injection (T0) and 1 month after the injection (T1).

RESULTS

The topographical sub-analysis revealed noteworthy changes in all rings at T1 compared to T0. There was a notable progressive reduction in FD% at T1 compared to T0 values across all rings, indicating a gradual CC reperfusion following anti-VEGF treatment. Additionally, the average size of FD decreased after the loading phase. Although not reaching statistical significance, there was a progressive reduction in the FDa across all rings.

CONCLUSION

Our study highlights a CC FD reduction following the administration of three consecutive faricimab injections. This effect was detected in all rings surrounding the dark halo. These observations suggest a partial CC reperfusion surrounding the MNV, potentially serving as an indicator for disease regression.

Repeatability of Rod-Mediated Dark Adaptation Testing in Normal Aging and Early and Intermediate Age-Related Macular Degeneration

PURPOSE

The vulnerability of rod photoreceptors in aging and early and intermediate age-related macular degeneration (AMD) has been well documented. Rod-mediated dark adaptation (RMDA) is a measure of the recovery of light sensitivity in rod photoreceptors following a bright light. Delays in RMDA during early and intermediate AMD have been widely reported. For RMDA's promise as an outcome for trials targeted at early and intermediate AMD to be realized, excellent test-retest reliability, its repeatability, must be established.

METHODS

Test-retest performance in a commonly used RMDA test based on the rod intercept time metric (RIT) was evaluated in participants with early and intermediate AMD and with normal retinal aging with testing approximately 2 weeks apart. The test target was placed at 5° eccentricity superior to the foveal center, an area with maximal rod loss in aging and AMD. Disease severity was identified by a trained and masked grader of fundus photographs using both the AREDS 9-step and Beckman classification systems. Bland-Altman plots and intra-class correlation coefficients (ICC) evaluated repeatability.

RESULTS

The analysis sample consisted of 37 older adults (mean age 76 years, standard deviation 5), with approximately one-third of the sample in each of three groups - normal aging, early AMD, and intermediate AMD. For the total sample, the ICC was 0.98. For individual AMD groups for both AREDS 9-step and Beckman classifications, the ICCs were also very high ranging from 0.82 to 0.99.

CONCLUSION

We demonstrated that RMDA testing using the RIT metric has excellent repeatability when target location is at 5° in studying older adults from normal aging to intermediate AMD, suggesting the reliable use of this functional measure in trials.

Choriocapillaris Impairment, Visual Function, and Distance to Fovea in Aging and Age-Related Macular Degeneration: ALSTAR2 Baseline

Purpose

In aging and early-intermediate age-related macular degeneration (AMD), rod-mediated dark adaptation (RMDA) slows more at 5° superior than at 12°. Using optical coherence tomography angiography (OCTA), we asked whether choriocapillaris flow deficits are related to distance from the fovea.

Methods

Persons ≥60 years stratified for AMD via the Age-Related Eye Disease Study's nine-step system underwent RMDA testing. Two adjacent 4.4° × 4.4° choriocapillaris OCTA slabs were centered on the fovea and 12° superior. Flow signal deficits (FD%) in concentric arcs (outer radii in mm, 0.5, 1.5, 2.2, 4.0, and 5.0 superior) were correlated with rod intercept time (RIT) and best-corrected visual acuity (BCVA).

Results

In 366 eyes (170 normal, 111 early AMD, 85 intermediate AMD), FD% was significantly worse with greater AMD severity in all regions (overall P < 0.05) and poorest under the fovea (P < 0.0001). In pairwise comparisons, FD% worsened with greater AMD severity (P < 0.05) at distances <2.2 mm. At greater distances, eyes with intermediate, but not early AMD differed from normal eyes. Foveal FD% was more strongly associated with longer RIT at 5° (r = 0.52) than RIT at 12° (r = 0.39) and BCVA (r = 0.21; all P < 0.0001). Choroidal thickness was weakly associated with longer RIT at 5° and 12° (r = 0.10-0.20, P < 0.05) and not associated with AMD severity.

Conclusions

Reduced transport across the choriocapillaris-Bruch's membrane-retinal pigment epithelium complex, which contributes to drusen formation under the macula lutea (and fovea), may also reduce retinoid resupply to rods encircling the high-risk area. FD% has potential as a functionally validated imaging biomarker for AMD emergence.

Calcified Drusen Prevent the Detection of Underlying Choriocapillaris Using Swept-Source Optical Coherence Tomography Angiography

Purpose

In age-related macular degeneration (AMD), choriocapillaris flow deficits (CCFDs) under soft drusen can be measured using established compensation strategies. This study investigated whether CCFDs can be quantified under calcified drusen (CaD).

Methods

CCFDs were measured in normal eyes (n = 30) and AMD eyes with soft drusen (n = 30) or CaD (n = 30). CCFD density masks were generated to highlight regions with higher CCFDs. Masks were also generated for soft drusen and CaD based on both structural en face OCT images and corresponding B-scans. Dice similarity coefficients were calculated between the CCFD density masks and both the soft drusen and CaD masks. A phantom experiment was conducted to simulate the impact of light scattering that arises from CaD.

Results

Area measurements of CCFDs were highly correlated with those of CaD but not soft drusen, suggesting an association between CaD and underlying CCFDs. However, unlike soft drusen, the detected optical coherence tomography (OCT) signals underlying CaD did not arise from the defined CC layer but were artifacts caused by the multiple scattering property of CaD. Phantom experiments showed that the presence of highly scattering material similar to the contents of CaD caused an artifactual scattering tail that falsely generated a signal in the CC structural layer but the underlying flow could not be detected. Similarly, CaD also caused an artifactual scattering tail and prevented the penetration of light into the choroid, resulting in en face hypotransmission defects and an inability to detect blood flow within the choriocapillaris. Upon resolution of the CaD, the CC perfusion became detectable.

Conclusions

The high scattering property of CaD leads to a scattering tail under these drusen that gives the illusion of a quantifiable optical coherence tomography angiography signal, but this signal does not contain the angiographic information required to assess CCFDs. For this reason, CCFDs cannot be reliably measured under CaD, and CaD must be identified and excluded from macular CCFD measurements.

Outer Retinal Thickness Is Associated With Cognitive Function in Normal Aging to Intermediate Age-Related Macular Degeneration

Purpose

Research on Alzheimer's disease (AD) and precursor states demonstrates a thinner retinal nerve fiber layer (NFL) compared to age-similar controls. Because AD and age-related macular degeneration (AMD) both impact older adults and share risk factors, we asked if retinal layer thicknesses, including NFL, are associated with cognition in AMD.

Methods

Adults ≥ 70 years with normal retinal aging, early AMD, or intermediate AMD per Age-Related Eye Disease Study (AREDS) nine-step grading of color fundus photography were enrolled in a cross-sectional study. Optical coherence tomography (OCT) volumes underwent 11-line segmentation and adjustments by a trained operator. Evaluated thicknesses reflect the vertical organization of retinal neurons and two vascular watersheds: NFL, ganglion cell layer-inner plexiform layer complex (GCL-IPL), inner retina, outer retina (including retinal pigment epithelium-Bruch's membrane), and total retina. Thicknesses were area weighted to achieve mean thickness across the 6-mm-diameter Early Treatment of Diabetic Retinopathy Study (ETDRS) grid. Cognitive status was assessed by the National Institutes of Health Toolbox cognitive battery for fluid and crystallized cognition. Correlations estimated associations between cognition and thicknesses, adjusting for age.

Results

Based on 63 subjects (21 per group), thinning of the outer retina was significantly correlated with lower cognition scores (P < 0.05). No other retinal thickness variables were associated with cognition.

Conclusions

Only the outer retina (photoreceptors, supporting glia, retinal pigment epithelium, Bruch's membrane) is associated with cognition in aging to intermediate AMD; NFL was not associated with cognition, contrary to AD-associated condition reports. Early and intermediate AMD constitute a retinal disease whose earliest, primary impact is in the outer retina. Our findings hint at a unique impact on the brain from the outer retina in persons with AMD.

Analysis of Choriocapillaris Reperfusion Topography following Faricimab Treatment for Neovascular Age-Related Macular Degeneration in Non-Treatment-Naïve Patients

To assess changes in choriocapillaris (CC) vascular density surrounding macular neovascularization (MNV) in age-related macular degeneration (AMD) when transitioning from various anti-VEGF treatments to faricimab, using optical coherence tomography angiography (OCTA). 25 eyes of 22 individuals who underwent intravitreal faricimab injections for neovascular AMD with type 1 MNV were included. OCTA images were obtained prior to (T0), after one (T1), and after three faricimab injections (T2); Noteworthy changes occurred in the first ring at T2 in comparison to T0. The percentage of CC flow deficit (FD%), FD average area (FDa), and FD number (FDn) in 5 rings (R1-R5) surrounding the dark halo around the MNV were calculated. A reduction in FD% at T2 compared to T0 (50.5 ± 10.2% at T0, 46.4 ± 10.6% at T2; p = 0.020) was seen, indicating CC reperfusion. Additionally, we observed a reduction in the average FDa (140.2 ± 172.1% at T0, 93.7 ± 101.8% at T2; p = 0.029). Our study highlights an FD% after three consecutive faricimab injections. The most pronounced effect was observed in the first ring, directly adjacent to the dark halo, suggesting a partial CC reperfusion surrounding the MNV, potentially indicating disease regression.

Age-Related Macular Degeneration, a Mathematically Tractable Disease

A progression sequence for age-related macular degeneration onset may be determinable with consensus neuroanatomical nomenclature augmented by drusen biology and eye-tracked clinical imaging. This narrative review proposes to supplement the Early Treatment of Diabetic Retinopathy Study (sETDRS) grid with a ring to capture high rod densities. Published photoreceptor and retinal pigment epithelium (RPE) densities in flat mounted aged-normal donor eyes were recomputed for sETDRS rings including near-periphery rich in rods and cumulatively for circular fovea-centered regions. Literature was reviewed for tissue-level studies of aging outer retina, population-level epidemiology studies regionally assessing risk, vision studies regionally assessing rod-mediated dark adaptation (RMDA), and impact of atrophy on photopic visual acuity. The 3 mm-diameter xanthophyll-rich macula lutea is rod-dominant and loses rods in aging whereas cone and RPE numbers are relatively stable. Across layers, the largest aging effects are accumulation of lipids prominent in drusen, loss of choriocapillary coverage of Bruch's membrane, and loss of rods. Epidemiology shows maximal risk for drusen-related progression in the central subfield with only one third of this risk level in the inner ring. RMDA studies report greatest slowing at the perimeter of this high-risk area. Vision declines precipitously when the cone-rich central subfield is invaded by geographic atrophy. Lifelong sustenance of foveal cone vision within the macula lutea leads to vulnerability in late adulthood that especially impacts rods at its perimeter. Adherence to an sETDRS grid and outer retinal cell populations within it will help dissect mechanisms, prioritize research, and assist in selecting patients for emerging treatments.

Subretinal drusenoid deposits, age-related macular degeneration, and cardiovascular disease

Decades of studies on age-related macular degeneration (AMD), cardiovascular disease and stroke have not found consistent associations between AMD and systemic vascular disease. This study suggests that there is in fact no general relationship, but instead a strong, specific association between only the subretinal drusenoid deposit (SDD) phenotype of AMD on retinal imaging and certain co-existent vascular diseases that are high risk for compromised cardiac output or internal carotid artery stenosis. Future screening initiatives for these high -risk vascular diseases (HRVDs) with fast, inexpensive retinal imaging could make a significant contribution to public health and save lives. Likewise, screening patients with known HRVDs for unrecognized AMD of the SDD form could enable needed treatment and save vision.