Histologic and Optical Coherence Tomographic Correlates in Drusenoid Pigment Epithelium Detachment in Age-Related Macular Degeneration

Structural OCT and OCT angiography biomarkers associated with the development and progression of geographic atrophy in AMD

BACKGROUND

Geographic atrophy (GA) is an advanced, irreversible, and progressive form of age-related macular degeneration (AMD). Structural optical coherence tomography (OCT) and OCT angiography (OCTA) have been largely used to characterize this stage of AMD and, more importantly, to define biomarkers associated with the development and progression of GA in AMD.

METHODS

Articles pertaining to OCT and OCTA biomarkers related to the development and progression of GA with relevant key words were used to search in PubMed, Researchgate, and Google Scholar. The articles were selected based on their relevance, reliability, publication year, published journal, and accessibility.

RESULTS

Previous reports have highlighted various OCT and OCTA biomarkers linked to the onset and advancement of GA. These biomarkers encompass characteristics such as the size, volume, and subtype of drusen, the presence of hyperreflective foci, basal laminar deposits, incomplete retinal pigment epithelium and outer retinal atrophy (iRORA), persistent choroidal hypertransmission defects, and the existence of subretinal drusenoid deposits (also referred to as reticular pseudodrusen). Moreover, biomarkers associated with the progression of GA include thinning of the outer retina, photoreceptor degradation, the distance between retinal pigment epithelium and Bruch's membrane, and choriocapillaris loss.

CONCLUSION

The advent of novel treatment strategies for GA underscores the heightened need for prompt diagnosis and precise monitoring of individuals with this condition. The utilization of structural OCT and OCTA becomes essential for identifying distinct biomarkers associated with the initiation and progression of GA.

Longitudinal Evaluation of the Distribution of Intraretinal Hyper-Reflective Foci in Eyes with Intermediate Age-Related Macular Degeneration

PURPOSE

Intraretinal hyper-reflective foci (IHRF) are optical coherence tomography (OCT) risk factors for progression of age-related macular degeneration (AMD). In this study we assess the change in the number and distribution of IHRF over two years.

METHODS

The axial distribution of IHRF were quantified in eyes with intermediate AMD (iAMD) at baseline and 24 months, using a series of 5 sequential equidistant en face OCT retinal slabs generated between the outer border of the internal limiting membrane (ILM) and the inner border of the retinal pigment epithelium (RPE). Following thresholding and binarization, IHRF were quantified in each retinal slab using ImageJ. The change in IHRF number in each slab between baseline and month 24 was calculated.

RESULTS

Fifty-two eyes showed evidence of IHRF at baseline, and all continued to show evidence of IHRF at 24 months (M24). The total average IHRF count/eye increased significantly from 4.67 ± 0.63 at baseline to 11.62 ± 13.86 at M24 (p < 0.001) with a mean increase of 6.94 ± 11.12 (range: - 9 to + 60). Overall, at M24, 76.9% eyes showed an increase in IHRF whereas 15.4% of eyes showed a decrease (3 eyes [5.7%] showed no change). There was a greater number of IHRF and a greater increase in IHRF over M24 in the outer slabs.

CONCLUSIONS

IHRF are most common in the outer retinal layers and tend to increase in number over time. The impact of the distribution and frequency of these IHRF on the overall progression of AMD requires further study.

Imaging Assessment of Peripapillary Vessel Diameters in Postmortem Eyes

PURPOSE

Proof of concept of ex vivo retinal vessel diameter measurements in human postmortem eyes.

METHODS

En face near-infrared (IR) images and optical coherence tomography (OCT) of the optic nerve head (ONH) were captured ex vivo with a Heidelberg Engineering Spectralis (Spectralis, version 7.0.4, Image Capture Module, version 1.2.4, Heidelberg Heidelberg, Germany) device, using a custom-made eye chamber holding and positioning the eyes during the image process. Thirty-two formaldehyde-fixated eyes of 16 patients were imaged. In the IR images, two independent graders measured retinal vessel diameters at the intersection of a drawn circle centered on the ONH with diameters of 2.0 mm and 3.4 mm, respectively. The anatomically corresponding measurements between both graders were statistically analyzed using a Wilcoxon signed-rank test.

RESULTS

A total of 246 matched measurements of both graders were analyzed across all 32 imaged eyes. Statistically significant differences between the graders were found for arterioles at 2 mm from the ONH. The other measurements did not show statistically significant intergrader differences. The mean values for arteriole diameters were 72.2 µm at 2.0 mm and 61.5 µm at 3.4 mm for grader 1, and 66.4 µm at 2.0 mm and 63.2 µm at 3.4 mm for grader 2. The mean diameter for venules were 75.5 µm at 2.0 mm and 79.3 µm at 3.4 mm for grader 1, and 67.4 µm at 2 mm and 79.1 µm at 3.4 mm for grader 2.

CONCLUSION

To the best of our knowledge, this is the first study to present IR image-based retinal vessel diameters in ex vivo postmortem eyes. Retinal IR/OCT imaging is possible, and measurements are reproducible in formaldehyde-fixated human eyes. Fixation artefacts result in lower image quality, and this can impose challenges in correctly detecting, classifying, and measuring retinal vessels.

Risk factors for development of hyper-reflective foci overlying drusen in eyes with intermediate age-related macular degeneration

AIMS

The aim of this study is to assess baseline characteristics of drusen preceding the development of intraretinal hyper-reflective foci (IHRF) in eyes with intermediate age-related macular degeneration (AMD).

METHODS

In this retrospective case-control study, longitudinal optical coherence tomography (OCT) volume data from eyes with intermediate AMD in a retina clinic population were screened. All drusen that developed overlying IHRF were marked. A random number generator was used to select for further grading three drusen that did not develop IHRF.

RESULTS

Ninety eyes (from 72 patients), including 140 drusen with overlying IHRF and 270 IHRF- drusen, were analysed. Greater drusen height, basal drusen width and overlying ellipsoid zone (EZ) and external limiting membrane disruption were associated with a significantly greater risk for IHRF development (p≤0.001). Regression analysis revealed EZ disruption increased these odds by 4.1 (p≤0.001). Each 10-µm increase in drusen height and width increased the odds by 34% (p≤0.001) and 3% (p: 0.005), respectively. Each 100-µm increase in distance from the fovea decreased the odds by 10% (p: 0.013).

CONCLUSIONS

The presence of overlying EZ disruption and a greater drusen height substantially increased the risk for IHRF development, whereas drusen further from the fovea indicated reduced risk. Given the importance of IHRF as a biomarker for AMD progression, these findings may be of value in defining patient populations for future early intervention trials.

Changes of optical coherence tomographic hyperreflective foci in rhegmatogenous retinal detachment patients after successful surgery

PURPOSE

To assess the changes of hyperreflective foci (HRF) in rhegmatogenous retinal detachment (RRD) patients after successful reattachment surgery.

METHODS

Twenty-nine macula-off RRD eyes with successful reattachment surgery were retrospectively analyzed. Optical coherence tomography (OCT) was used to image macular regions and measure HRF in outer retina and inner retina at 0.5, 1, 3, 6, 12 months after surgery. The relationships between HRF and photoreceptor layer status, visual outcomes were evaluated.

RESULTS

After retinal reattachment, HRF mainly distributed at the location where external limiting membrane (ELM) or inner and outer segment (IS/OS) line was disrupted. The HRF numbers in outer and inner retina were greater in eyes with discontinuous IS/OS line than eyes with continuous IS/OS line (all p<0.05). In the outer retina,  HRF increased in the initial three months after retinal reattachment, and then decreased gradually after 3 months (p<0.05). The HRF number in the outer retina at postoperative 0.5 months was associated with favorable visual outcomes at 6 and 12 months (r=-0.487,  p =0.025; r=-0.626,  p=0.005, respectively), nevertheless, the HRF number at 3 months was correlated with poor visual results at 6 and 12 months (r=0.441,  p =0.017; r=0.477,  p=0.019, respectively).

CONCLUSION

HRF mainly occurred near the site where ELM or IS/OS line was injured after retinal reattachment. In the outer retina, the number of HRF gradually increased in the first 3 months and then gradually decreased. The early appearance of HRF in the outer retina was associated with a good visual prognosis, while the late appearance may suggest a less favorable visual outcome.

Intraretinal pigmented cells in retinal degenerative disease

PURPOSE

Invasion of pigmented cells into the retina occurs in retinal degenerative diseases, such as macular telangiectasia type 2 (MacTel) and retinitis pigmentosa (RP). These intraretinal pigmented cells may be derived from the retinal pigment epithelium (RPE), but differences and similarities between intraretinal pigmented cells and RPE have so far not been well characterised.Clinicopathologic case report.

METHOD

Here, we compared intraretinal pigment cells with RPE cells by immunohistochemistry. Immunohistological stains for classic RPE markers (RPE65, CRALBP and KRT18) and blood vessel markers (lectin and collagen 4) were done on sections from postmortem eye tissue from two MacTel donors, an RP donor and a control donor.

MAIN OUTCOME MEASURES

Presence of specific immunohistochemistry markers on intraretinal pigmented and RPE cells.

RESULTS

We found that intraretinal pigmented cells did not express RPE65 and CRALBP, with a small subset expressing them weakly. However, they all expressed KRT18, which was also present in normal RPE cells. Interestingly, we also found clusters of KRT18-positive cells in the retina that were not pigmented.

CONCLUSIONS

Our findings suggest that RPE cells invading the retina dedifferentiate (losing classic RPE markers) and can be pigmented or unpigmented. Therefore, the number of RPE cells invading the retina in retinal degenerative disease may be underappreciated by funduscopy.

Lipofilling Enriched with Adipose-Derived Mesenchymal Stem Cells Improves Soft Tissue Deformities and Reduces Scar Pigmentation: Clinical and Instrumental Evaluation in Plastic Surgery

BACKGROUND

Scars and soft tissue deformities (S-STDs), often resulting from hemifacial atrophy, trauma, and outcomes of burns, were usually associated with hyperpigmentation of overlying skin.

OBJECTIVES

This study aimed to evaluate the long-term effects of fat grafting commonly called "Lipofilling" enhanced with adipose-derived mesenchymal stem cells (Lipofilling-AD-MSCs) for treating S-STDs with pigmentary changes.

METHODS

A cohort study has been performed. 50 patients affected by S-STDs with hyperpigmentation treated with Lipofilling-AD-MSCs and 50 patients treated with Lipofilling not enhanced (Lipofilling-NE) were prospectively assessed. The pre-op evaluation included a clinical evaluation, a photographic assessment, magnetic resonance imaging, and ultrasound. Post-op follow-up was performed at 1, 3, 7, 12, 24, 48, weeks, and then annually.

RESULTS

Improvement in volume contours and pigmentation was clinically assessed. All people who underwent the treatments (Lipofilling-AD-MSCs and Lipofilling-NE) were satisfied with the improving pigmentation, texture, and volume contours with some differences. However, the results reported displaying a better trend in patients treated with Lipofilling-AD-MSCs to be more satisfied than patients treated with Lipofilling-NE (p < 0.0001).

CONCLUSIONS

In conclusion, Lipofilling-AD-MSCs was the preferred option for improving the contour deformities related to increased pigmentation of scars.

LEVEL OF EVIDENCE IV

Evidence obtained from cohort studies.

Longitudinal evaluation of the distribution of intraretinal hyper-reflective foci in eyes with intermediate age-related macular degeneration

Purpose

Intraretinal hyper-reflective foci (IHRF) are optical coherence tomography (OCT) risk factors for progression of age-related macular degeneration (AMD). In this study we assess the change in the number and distribution of IHRF over two years.

Methods

The axial distribution of IHRF were quantified in eyes with intermediate AMD (iAMD) at baseline and 24 months, using a series of 5 sequential equidistant en face OCT retinal slabs generated between the outer border of the internal limiting membrane (ILM) and the inner border of the retinal pigment epithelium (RPE). Following thresholding and binarization, IHRF were quantified in each retinal slab using ImageJ. The change in IHRF number in each slab between baseline and month 24 was calculated.

Results

Fifty-two eyes showed evidence of IHRF at baseline, and all continued to show evidence of IHRF at 24 months (M24). The total average IHRF count/eye increased significantly from 4.67 ± 0.63 at baseline to 11.62 ± 13.86 at M24 (p<0.001) with a mean increase of 6.94 ± 11.12 (range: - 9 to + 60). Overall, at M24, 76.9% eyes showed an increase in IHRF whereas 15.4% of eyes showed a decrease (4 eyes [7.6%] showed no change). There was a greater number of IHRF and a greater increase in IHRF over M24 in the outer slabs.

Conclusions

IHRF are most common in the outer retinal layers and tend to increase in number over time. The impact of the distribution and frequency of these IHRF on the overall progression of AMD requires further study.

SUBRETINAL FLUID ASSOCIATED WITH DRUSENOID PIGMENT EPITHELIAL DETACHMENT

PURPOSE

To analyze the clinical characteristics of drusenoid pigment epithelial detachment (PED) with subretinal fluid (SRF) and to evaluate the impact of SRF on the long-term visual and anatomical outcomes.

METHODS

Forty-seven eyes with drusenoid PED (47 patients) who completed >24 months of follow-up were retrospectively analyzed. Intergroup comparisons of the visual and anatomical outcomes with and without SRF were made.

RESULTS

The mean duration of follow-up was 32.9 ± 18.7 months. The group with drusenoid PED with SRF (14 eyes) showed significantly higher PED height (468 ± 130 µ m vs. 313 ± 88 µ m, P < 0.001), larger PED diameter (2,328 ± 953 µ m vs. 1,227 ± 882 µ m, P < 0.001), and larger PED volume (1.88 ± 1.73 mm 3 vs. 1.12 ± 1.35 mm 3 , P = 0.021) than that in the group with drusenoid PED without SRF (33 eyes) at baseline. No significant intergroup difference was found regarding the best-corrected visual acuity at the final visit. In addition, the incidence of complete retinal pigment epithelial and outer retinal atrophy (cRORA; 21.4%) and the development of macular neovascularization (MNV; 7.1%) for the group with drusenoid PED with SRF showed no difference compared with those (39.4% for cRORA development and 9.1% for MNV development) with drusenoid PED without SRF.

CONCLUSION

The size, height, and volume of drusenoid PED were associated with the development of SRF. The SRF in drusenoid PED did not affect the visual prognosis or the development of macular atrophy during long-term follow-up.

Advances and prospects for the Human BioMolecular Atlas Program (HuBMAP)

The Human BioMolecular Atlas Program (HuBMAP) aims to create a multi-scale spatial atlas of the healthy human body at single-cell resolution by applying advanced technologies and disseminating resources to the community. As the HuBMAP moves past its first phase, creating ontologies, protocols and pipelines, this Perspective introduces the production phase: the generation of reference spatial maps of functional tissue units across many organs from diverse populations and the creation of mapping tools and infrastructure to advance biomedical research.

HYPERREFLECTIVE FOCI PRECEDE MACULAR NEOVASCULARIZATION FORMATION IN ANGIOID STREAKS

PURPOSE

To describe the steps leading to the development and progression of macular neovascularization (MNV) in angioid streaks.

METHODS

The study was designed as retrospective, longitudinal case series. Patients with angioid streaks were investigated by means of multimodal imaging, including fundus autofluorescence and structural optical coherence tomography. Main outcome measures were hyperreflective foci and MNV progression steps.

RESULTS

Overall, 40 eyes (20 patients) affected by angioid streaks were evaluated. Over the follow-up, five eyes of five patients developed MNV. The mean follow-up was of 1.6 years. The mean number of anti-vascular endothelial growth factor injections was 4.35 ± 1.4. Mean best-corrected visual acuity was 0.53 ± 0.38 LogMAR at the MNV onset, improving to 0.42 ± 0.40 LogMAR at the end of the follow-up ( P > 0.05). Intraretinal hyperreflective foci onset and coalescence represented the first alterations occurring before the onset of the MNV. Anti-vascular endothelial growth factor treatment was associated with exudation relapsing and remitting, with still present intraretinal hyperreflective foci and pigment accumulation. The longitudinal analysis of our cohort of eyes outlined the event timeline: 1.2 months to find concentrated hyperreflective foci, 4.5 months to observe pigment organization through the outer nuclear layer, and 1.5 years to detect MNV.

CONCLUSION

Hyperreflective foci formation, concentration, and migration represent early alterations occurring before the onset of the MNV in angioid streaks.

Biologically Guided Optimization of Test Target Location for Rod-mediated Dark Adaptation in Age-related Macular Degeneration: Alabama Study on Early Age-related Macular Degeneration 2 Baseline

Purpose

We evaluate the impact of test target location in assessing rod-mediated dark adaptation (RMDA) along the transition from normal aging to intermediate age-related macular degeneration (AMD). We consider whether RMDA slows because the test locations are near mechanisms leading to or resulting from high-risk extracellular deposits. Soft drusen cluster under the fovea and extend to the inner ring of the ETDRS grid where rods are sparse. Subretinal drusenoid deposits (SDDs) appear first in the outer superior subfield of the ETDRS grid where rod photoreceptors are maximal and spread toward the fovea without covering it.

Design

Cross-sectional.

Participants

Adults ≥ 60 years with normal older maculas, early AMD, or intermediate AMD as defined by the Age-Related Eye Disease Study (AREDS) 9-step and Beckman grading systems.

Methods

In 1 eye per participant, RMDA was assessed at 5° and at 12° in the superior retina. Subretinal drusenoid deposit presence was identified with multi-modal imaging.

Main Outcome Measures

Rod intercept time (RIT) as a measure of RMDA rate at 5° and 12°.

Results

In 438 eyes of 438 persons, RIT was significantly longer (i.e., RMDA is slower) at 5° than at 12° for each AMD severity group. Differences among groups were bigger at 5° than at 12°. At 5°, SDD presence was associated with longer RIT as compared to SDD absence at early and intermediate AMD but not in normal eyes. At 12°, SDD presence was associated with longer RIT in intermediate AMD only, and not in normal or early AMD eyes. Findings were similar in eyes stratified by AREDS 9-step and Beckman systems.

Conclusions

We probed RMDA in relation to current models of deposit-driven AMD progression organized around photoreceptor topography. In eyes with SDD, slowed RMDA occurs at 5° where these deposits typically do not appear until later in AMD. Even in eyes lacking detectable SDD, RMDA at 5° is slower than at 12°. The effect at 5° may be attributed to mechanisms associated with the accumulation of soft drusen and precursors under the macula lutea throughout adulthood. These data will facilitate the design of efficient clinical trials for interventions that aim to delay AMD progression.

OPTICAL COHERENCE TOMOGRAPHY FEATURES RELEVANT TO NEOVASCULAR AGE-RELATED MACULAR DEGENERATION MANAGEMENT AND NONNEOVASCULAR AGE-RELATED MACULAR DEGENERATION PROGRESSION: CLINICOPATHOLOGIC CORRELATION

PURPOSE

Clinicopathologic correlation of two optical coherence tomography (OCT) features in neovascular age-related macular degeneration.

METHODS

Case report, clinicopathologic correlation.

RESULTS

A patient in her 90s was diagnosed with Type 3 macular neovascularization secondary to age-related macular degeneration in the index right eye and underwent intravitreal antivascular endothelial growth factor treatment for 5 years. A double-layer sign on in vivo OCT was correlated to calcified drusen on histology. Furthermore, hyperfluorescence on fluorescein angiography corresponded on histology to choroidal hypertransmission on OCT and retinal pigment epithelium atrophy above calcified drusen.

CONCLUSION

A double-layer sign on OCT can represent nonneovascular subretinal pigment epithelium material including wide and flat calcific nodules. Furthermore, hyperfluorescence on FA, among different origins, can be due to a window defect corresponding to retinal pigment epithelium atrophy, which can be confirmed with OCT. Clinicopathological correlation using high-resolution histology can demonstrate the fine details available to clinical decision making through currently available in vivo OCT imaging.

Ex Vivo OCT-Based Multimodal Imaging of Human Donor Eyes for Research into Age-Related Macular Degeneration

A progression sequence for age-related macular degeneration (AMD) learned from optical coherence tomography (OCT)-based multimodal (MMI) clinical imaging could add prognostic value to laboratory findings. In this work, ex vivo OCT and MMI were applied to human donor eyes prior to retinal tissue sectioning. The eyes were recovered from non-diabetic white donors aged ≥80 years old, with a death-to-preservation time (DtoP) of ≤6 h. The globes were recovered on-site, scored with an 18 mm trephine to facilitate cornea removal, and immersed in buffered 4% paraformaldehyde. Color fundus images were acquired after anterior segment removal with a dissecting scope and an SLR camera using trans-, epi-, and flash illumination at three magnifications. The globes were placed in a buffer within a custom-designed chamber with a 60 diopter lens. They were imaged with spectral domain OCT (30° macula cube, 30 µm spacing, averaging = 25), near-infrared reflectance, 488 nm autofluorescence, and 787 nm autofluorescence. The AMD eyes showed a change in the retinal pigment epithelium (RPE), with drusen or subretinal drusenoid deposits (SDDs), with or without neovascularization, and without evidence of other causes. Between June 2016 and September 2017, 94 right eyes and 90 left eyes were recovered (DtoP: 3.9 ± 1.0 h). Of the 184 eyes, 40.2% had AMD, including early intermediate (22.8%), atrophic (7.6%), and neovascular (9.8%) AMD, and 39.7% had unremarkable maculas. Drusen, SDDs, hyper-reflective foci, atrophy, and fibrovascular scars were identified using OCT. Artifacts included tissue opacification, detachments (bacillary, retinal, RPE, choroidal), foveal cystic change, an undulating RPE, and mechanical damage. To guide the cryo-sectioning, OCT volumes were used to find the fovea and optic nerve head landmarks and specific pathologies. The ex vivo volumes were registered with the in vivo volumes by selecting the reference function for eye tracking. The ex vivo visibility of the pathology seen in vivo depends on the preservation quality. Within 16 months, 75 rapid DtoP donor eyes at all stages of AMD were recovered and staged using clinical MMI methods.

Fat grafts enriched with ex-vivo expanded adipose stem cells improve hyperpigmentation of face

Facial contour deformities associated with pigmentary changes are of major concern for plastic surgeons being difficult to treat. No definite ideal treatment option is available to address simultaneously both the contour defects as well as related hyperpigmentation. The aim of the current study is to compare long-term effects of conventional adipose tissue grafting and ex-vivo expanded ASC-enriched adipose tissue grafting for the treatment of contour deformities related pigmentary changes on the face. In this study, 80 patients of contour deformities of face with hyperpigmentation were recruited after informed consent. Two techniques, that is, conventional fat grafting (C-FG) and fat grafts enriched with expanded adipose stem cells (FG-ASCs) were used to address the pigmentation. Both techniques were explained to patients and enrolled patients were divided into two groups, that is, C-FG and FG-ASCs as per patients' choice and satisfaction. Patients of the FG-ASCs group were treated with FG-ASCs while patients of C-FGs group were treated with C-FG (without expanded ASCs). Patients were followed for 12 months and improvement in face pigmentation was assessed clinically as well as measured objectively. Patients' satisfaction was also documented as highly satisfied, satisfied, and unsatisfied. This clinical trial was registered at www.clinicaltrials.gov with ID: NTC03564808. Mean age of patients was 24.42 (±4.49), 66 patients were females. Forehead was involved in 61.20% cases, cheek in 21.20% cases, chin in 11.20% cases, and nose in 6.20% cases. In GF-ASCs group, the integrated color density was decreased (1.08 × 10⁶  ± 4.64 × 10⁵ ) as compared with C-FG group (2.80 × 10⁵  ± 1.69 × 10⁵ ). Patients treated with fat grafts enriched with expanded ASCs were significantly more satisfied as compared with patients treated with C-FG only. In conclusion, ASC-enriched autologous fat grafting is preferred option for improving the contour deformities related increased pigmentation of face skin.

Melanophages give rise to hyperreflective foci in AMD, a disease-progression marker

Retinal melanosome/melanolipofuscin-containing cells (MCCs), clinically visible as hyperreflective foci (HRF) and a highly predictive imaging biomarker for the progression of age-related macular degeneration (AMD), are widely believed to be migrating retinal pigment epithelial (RPE) cells. Using human donor tissue, we identify the vast majority of MCCs as melanophages, melanosome/melanolipofuscin-laden mononuclear phagocytes (MPs). Using serial block-face scanning electron microscopy, RPE flatmounts, bone marrow transplantation and in vitro experiments, we show how retinal melanophages form by the transfer of melanosomes from the RPE to subretinal MPs when the "don't eat me" signal CD47 is blocked. These melanophages give rise to hyperreflective foci in Cd47^-/--mice in vivo, and are associated with RPE dysmorphia similar to intermediate AMD. Finally, we show that Cd47 expression in human RPE declines with age and in AMD, which likely participates in melanophage formation and RPE decline. Boosting CD47 expression in AMD might protect RPE cells and delay AMD progression.

Histology of type 3 macular neovascularization and microvascular anomalies in treated age-related macular degeneration: a case study

Purpose

To investigate intraretinal neovascularization and microvascular anomalies by correlating in vivo multimodal imaging with corresponding ex vivo histology in a single patient.

Design

A case study comprising clinical imaging from a community-based practice, and histologic analysis at a university-based research laboratory (clinicopathologic correlation).

Participants

A White woman in her 90s treated with numerous intravitreal anti-VEGF injections for bilateral type 3 macular neovascularization (MNV) secondary to age-related macular degeneration (AMD).

Methods

Clinical imaging comprised serial infrared reflectance, eye-tracked spectral-domain OCT, OCT angiography, and fluorescein angiography. Eye tracking, applied to the 2 preserved donor eyes, enabled the correlation of clinical imaging signatures with high-resolution histology and transmission electron microscopy.

Main Outcome Measures

Histologic/ultrastructural descriptions and diameters of vessels seen in clinical imaging.

Results

Six vascular lesions were histologically confirmed (type 3 MNV, n = 3; deep retinal age-related microvascular anomalies [DRAMAs], n = 3). Pyramidal (n = 2) or tangled (n = 1) morphologies of type 3 MNV originated at the deep capillary plexus (DCP) and extended posteriorly to approach without penetrating persistent basal laminar deposit. They did not enter the subretinal pigment epithelium (RPE)-basal laminar space or cross the Bruch membrane. Choroidal contributions were not found. The neovascular complexes included pericytes and nonfenestrated endothelial cells, within a collagenous sheath covered by dysmorphic RPE cells. Deep retinal age-related microvascular anomaly lesions extended posteriorly from the DCP into the Henle fiber and the outer nuclear layers without evidence of atrophy, exudation, or anti-VEGF responsiveness. Two DRAMAs lacked collagenous sheaths. External and internal diameters of type 3 MNV and DRAMA vessels were larger than comparison vessels in the index eyes and in aged normal and intermediate AMD eyes.

Conclusions

Type 3 MNV vessels reflect specializations of source capillaries and persist during anti-VEGF therapy. The collagenous sheath of type 3 MNV lesions may provide structural stabilization. If so, vascular characteristics may be useful in disease monitoring in addition to fluid and flow signal detection. Further investigation with longitudinal imaging before exudation onset will help determine if DRAMAs are part of the type 3 MNV progression sequence.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Fluorescence Lifetime and Spectral Characteristics of Subretinal Drusenoid Deposits and Their Predictive Value for Progression of Age-Related Macular Degeneration

Purpose

To measure fundus autofluorescence (FAF) lifetimes and peak emission wavelengths (PEW) of subretinal drusenoid deposits (SDD) in age-related macular degeneration (AMD) and their development over time.

Methods

Fluorescence lifetime imaging ophthalmoscopy (FLIO) was performed in 30 eyes with optical coherence tomography (OCT)-confirmed early or intermediate AMD and SDD. Contrasts of mean lifetimes in short- (SSC) and long-wavelength channels (LSC), PEW, and relative fluorescence intensity were determined as differences of the respective measures at individual SDD and their environment. Measurements were made at baseline and at follow-up intervals 1 (13-36 months) and 2 (37-72 months), respectively.

Results

Of 423 SDD found at baseline, 259, 47, and 117 were hypoautofluorescent, isoautofluorescent, and hyperautofluorescent, respectively. FAF lifetimes of SDD were significantly longer than those of their environment by 14.5 ps (SSC, 95% confidence interval [CI], 13.3-15.7 ps) and 3.9 ps (LSC, 3.1-4.7 ps). PEW was shorter by 1.53 nm (1.07-1.98 nm, all contrasts P < 0.001) with higher contrasts for hyperfluorescent SDD. Over follow-up, SDD tended to hyperautofluorescence (relative intensities increased by 3.4% [95% CI, 2.9%-4.1%; P < 0.001] in follow-up 2). Hyperautofluorescence was associated with disruption of the ellipsoid zone on OCT. Disease progression to late-stage AMD was associated with higher lifetime contrast in SSC (15.9ps [14.2-17.6 ps] vs. 11.7 ps [9.9-13.5 ps], P < 0.001) at baseline.

Conclusions

SDD show longer FAF lifetimes and shorter PEW than their environments. A high lifetime contrast of SDD in SSC might predict disease progression to late-stage AMD.

Prolonged Lifetimes of Histologic Autofluorescence in Ectopic Retinal Pigment Epithelium in Age-Related Macular Degeneration

Purpose

The purpose of this study was to investigate histologic autofluorescence lifetimes and spectra of retinal pigment epithelium (RPE) on the transition from normal aging to RPE activation and migration in age-related macular degeneration (AMD).

Methods

Autofluorescence lifetimes and spectra of 9 donor eyes were analyzed in cryosections by means of 2-photon excited fluorescence at 960 nm. Spectra were detected at 483 to 665 nm. Lifetimes were measured using time-correlated single photon counting in 2 spectral channels: 500 to 550 nm (short-wavelength spectral channel [SSC]) and 550 to 700 nm (long-wavelength spectral channel [LSC]). Fluorescence decays over time were approximated by a series of three exponential functions. The amplitude-weighted mean fluorescence lifetime was determined. Markers for retinoid activity (RPE65) and immune function (CD68) were immunolocalized in selected neighboring sections.

Results

We identified 9 RPE morphology phenotypes resulting in 399 regions of interest (ROIs) for spectral and 497 ROIs for lifetime measurements. RPE dysmorphia results in a shorter wavelength peak of spectral emission: normal aging versus RPE migrated into the retina (intraELM) = 601.7 (9.5) nm versus 581.6 (7.3) nm, P < 0.001, whereas autofluorescence lifetimes increase: normal aging versus intraELM: SSC 180 (44) picosecond (ps) versus 320 (86) ps, P < 0.001; and LSC 250 (55) ps versus 441 (76) ps, P < 0.001. Ectopic RPE within the neurosensory retina is strongly CD68 positive and RPE65 negative.

Conclusions

In the process of RPE degeneration, comprising different steps of dysmorphia and migration, lengthening of autofluorescence lifetimes and a hypsochromic shift of emission spectra can be observed. These autofluorescence changes might provide early biomarkers for AMD progression and contribute to our understanding of RPE-driven pathology.

Hyperreflective Foci in Age-Related Macular Degeneration are Associated with Disease Severity and Functional Impairment

PURPOSE

To analyze presence of hyperreflective foci (HRF) across different age-related macular degeneration (AMD) severities and examine its correlation with other structural and functional AMD features.

DESIGN

Longitudinal, single-center, case-control study.

PARTICIPANTS

One hundred and fifty-eight participants aged > 50 years old with varying AMD severities (including no AMD).

METHODS

Color fundus imaging was used to assess AMD severity and hyperpigmentation (PGM) presence. Subretinal drusenoid deposits (SDD) and HRF were detected on OCT volumes. The correlations of HRF with additional AMD features were evaluated using linear and logistic mixed-effects models. One study eye per participant underwent dark adaptation (DA) testing to measure rod intercept time (RIT) for structure function associations. Eyes were followed longitudinally and changes in AMD severity and RIT were measured relative to HRF presence.

MAIN OUTCOME MEASURES

The primary outcome was presence of HRF, which was compared with presence of other AMD features and DA impairment.

RESULTS

One hundred and fifty-eight participants (median baseline age of 73.1 [interquartile range (IQR) = 66-79] years) contributing 1277 eye visits were included. Hyperreflective foci (HRF) were detected more frequently in higher AMD severities. Hyperreflective-foci presence was significantly associated with PGM presence (odds ratio 832.9, P < 0.001) and SDD presence (odds ratio 9.42, P = 0.017). Eyes with HRF demonstrated significantly longer DA (median 27.1 [IQR = 16-40] minutes) than those without HRF (13.5 [10-22] minutes) but less than eyes with SDD only (40 [28-40] minutes). Highest RIT values were found in eyes with both HRF and SDD (40.0 [40-40] minutes). Age and HRF explained a similar proportion of RIT variability as age and SDD. Eyes that developed HRF demonstrated baseline RITs closer to eyes with HRF at baseline, compared with eyes that never developed HRF (29.1 [16-40], 38.5 [22-40] versus 13.1 [10-22] minutes; Kruskal-Wallis P < 0.001).

CONCLUSIONS

The progressively increased presence of HRF in higher AMD severities, and its correlation with previously associated AMD biomarkers, suggests HRF is an important OCT feature adding to the understanding of disease progression. Hyperreflective foci presence was associated with delays in DA, indicating HRF is a marker for visual cycle impairment.

FINANCIAL DISCLOSURE

Proprietary or commercial disclosure may be found after the references.

Relationship Between Drusen Height and OCT Biomarkers of Atrophy in Non-Neovascular AMD

Purpose

To determine if increasing drusen height correlates with predictive optical coherence tomography (OCT) biomarkers of atrophy.

Methods

Retrospective cross-sectional study that enrolled patients with drusen associated with intermediate AMD. Macular drusen were classified as small, intermediate, large, or very large based on OCT quartile measurement of height. Drusen diameter was also tabulated. The presence and localization of the OCT biomarkers of atrophy were assessed: disruption of the external limiting membrane and ellipsoid zone, intraretinal hyper-reflective foci, RPE disruption, choroidal hypertransmission, and presence of hyporeflective cores. Predictive OCT biomarkers of atrophy were correlated with drusen height.

Results

A total of 155 eyes from 104 patients met the inclusion and exclusion criteria. The mean age was 75.7 ± 8.7 years, and patients were predominantly female (74.0%). The mean visual acuity was logMAR 0.2 ± 0.2 (Snellen equivalent 20/32). The average drusen height was 134.6 ± 107.5 µm and the greatest horizontal diameter was 970.7 ± 867.4 µm. Disruption of the external limiting membrane and ellipsoid zone, RPE thickening or thinning, intraretinal hyper-reflective foci, choroidal hypertransmission, and presence of hyporeflective cores (P < 0.05) were more common in eyes with large drusen and very large drusen versus small or intermediate drusen. All biomarkers were positively correlated with drusen height. OCT biomarkers of atrophy were predominantly located at the apex of the drusen.

Conclusions

Predictive OCT biomarkers of atrophy, specifically signs of RPE breakdown and disruption, occur more commonly in large or very large drusen, especially in drusen with greater height and separation of the RPE from the underlying choroid.

Sub-retinal pigment epithelium tubules in non-neovascular age-related macular degeneration

To describe a novel optical coherence tomography (OCT) signature resembling sub-retinal pigment epithelium (RPE) tubules (SRT) in non-neovascular age-related macular degeneration (AMD). Patients suffering from non-neovascular AMD with complete medical records and multimodal imaging were retrospectively revised in three different tertiary care centers. Multimodal imaging included color fundus photograph, spectral-domain OCT (Spectralis, Heidelberg Engineering, Germany), fundus autofluorescence, OCT angiography (RTVue XR Avanti, Optovue, Inc., Fremont, CA). A total of 7 eyes of 7 patients with drusenoid pigment epithelium detachment (PED) were consecutively analyzed. The sub-RPE tubules appeared as ovoidal structures with a hyperreflective contour and hyporeflective interior appreciable in the sub-RPE-basal lamina (BL) space on OCT B-scan. The anatomical location of the sub-RPE formations was lying above the Bruch’s membrane in 5/7 cases (71.4%) or floating in the sub-RPE-BL space in 2/7 cases (28.6%). En-face OCTA revealed a curvilinear tubulation-like structure corresponding to SRT without flow signal. Sub-RPE tubules represent a newly identified OCT signature observed in eyes with drusenoid PED. The presumed origin may include a variant of calcified structure or alternatively activated RPE cells with some residual BL or basal laminar deposits attracted to BrM for craving oxygen.

Ageing fundus degenerations of Macaca fascicularis on multi-modal imaging and histopathology: Similarities and differences compared to human

To characterize the ageing fundus degenerations in Macaca fascicularis, we used multimodal imaging including color fundus photograph, spectral domain optical coherence tomography, fundus autofluorescence, fundus fluorescence angiography, and indocyanine green angiography (ICGA) to survey and track fundus changes of 84 Macaca fascicularis, ranging from 5 to 24 years old over 2 years, and followed by hematoxylin-eosin (HE) and immunofluorescence (IF) staining. The Macaca fascicularis in our cohort showed ageing characteristics different from human, including the more common yellow dot maculopathy, the unique appearance of patchy hyperautoflurescence, and the absence of subretinal drusenoid deposit, basal laminar deposit, geographic atrophy or choroidal neovascularization. Same with human, hard drusen, soft drusen, atherosclerosis, tessellated retina, staining of vessels in peripheral choroid on late-phase ICGA, and peripheral hard drusen were detected. HE and IF staining suggested the patchy hyperautoflurescence to be drusenoid deposits. BMI were significantly higher in the Macaca fascicularis with yellow dot maculopathy and hard drusen, compared to the ones without (p < 0.05). Our study reveals fundus degenerations that develop with ageing in the nonhuman primate of Macaca fascicularis. Their differences and similarities compared to human worth notice by future translational research in degenerative fundus diseases, especially age-related macular degeneration.

Optical Coherence Tomography Imaging: Advances in Ophthalmology

Since its advent in 1991, optical coherence tomography (OCT) has become the most commonly used imaging modality in vitreo-retina practice [...].

Blue-light fundus autofluorescence imaging of pigment epithelial detachments

BACKGROUND

Pigment epithelial detachments (PEDs) occur in association with various chorioretinal diseases. With respect to the broad clinical spectrum of PEDs we describe fundus autofluorescence (FAF) characteristics of PEDs.

METHODS

Ninety-three eyes of 66 patients (mean age 71.9 ± 11.1) with uni- or bilateral PED ( ≥ 350 µm) were included in a retrospective cross-sectional study. PEDs were secondary to age-related macular degeneration (n = 79), central serous chorioretinopathy (n = 7), polypoidal choroidal vasculopathy (n = 2), pattern dystrophy (n = 3) or idiopathic PED (n = 2). FAF images were recorded using confocal scanning laser ophthalmoscopy (488 nm excitation wavelength, detection of emission >500 nm). Diagnosis of PED was confirmed using spectral-domain optical coherence tomography. A qualitative FAF grading system was established, and grading was performed by two independent readers.

RESULTS

PEDs showed highly variable characteristics on FAF imaging. FAF within the area of PED was found to be irregular/granular (n = 59, 63.4%), increased (n = 28, 30.1%), decreased (n = 3, 3.2 %), or normal (n = 3, 3.2%). Accompanying FAF changes included condensation of macular pigment (n = 67, 72.0%), focally increased FAF at the PED apex (n = 14, 15.1%) or elsewhere (n = 52, 55.9%), focally decreased FAF (n = 23, 24.7%), a cartwheel-like pattern (n = 10, 10.8%), a doughnut sign (n = 6, 6.5%), and a halo of decreased FAF encircling the PED (completely n = 20, 21.5% or incompletely n = 20, 21.5%).

CONCLUSIONS

PEDs show a variety of abnormal patterns on FAF imaging. These changes in FAF signals may be secondary to morphological and metabolic alterations within corresponding retinal layers and do not necessarily correspond with the underlying PED subtype or a specific pathology.

Correlation of Optical Coherence Tomography Angiography of Type 3 Macular Neovascularization With Corresponding Histology

Importance

By validating optical coherence tomography angiography (OCTA) in the analysis of type 3 macular neovascularization secondary to age-related macular degeneration, the overall value of clinical OCTA for disease observation, diagnosis, and staging is increased.

Objective

To assess the association of in vivo OCTA of type 3 macular neovascularization secondary to age-related macular degeneration with corresponding ex vivo histology.

Design, Setting, and Participants

This study included clinical imaging, laboratory microscopy, and eye-tracked clinicopathologic correlation of a single case from a community-based practice evaluated at a university-based research laboratory from 2014 to 2019.

Exposures

Infrared reflectance and eye-tracked spectral-domain OCTA clinical imaging was correlated with ex vivo high-resolution histologic images of the preserved donor eye. Eye tracking, applied to the donor eye, enabled identification of histologic features corresponding with clinical OCTA signatures. Projection artifact removal based on 2-dimensional vessel-shape estimation and a Gaussian blur filter demonstrated a robust preservation of neovascular flow signal.

Main Outcomes and Measures

Histology findings associated with clinical OCTA signatures. Three-dimensional view of neovascularization via video.

Results

A White woman in her 90s with type 3 neovascularization secondary to age-related macular degeneration was treated with 37 intravitreal injections of ranibizumab and aflibercept in the right eye. The index lesion displayed a drusenoid pigment epithelium detachment, characteristic of type 3 neovascularization. OCTA decorrelation signal in the index lesion corresponded in histology to a collagen-ensheathed vascular complex contacting basal laminar deposit that outlasted the retinal pigment epithelium. The subretinal pigment epithelium-basal laminar space contained calcified material and glial processes. No connection between the choriocapillaris and this space was observed. Video showed a columnar tangle of flow signal in the outer nuclear layer, with inflow and outflow vessels connecting to the superficial artery and vein.

Conclusions and Relevance

While this study presents only 1 case in which a vascular connection between subretinal pigment epithelium-basal laminar space and choriocapillaris was undetected, these results support the potential value of OCTA for diagnosis. OCTA decorrelation signal of type 3 neovascularization corresponded with intraretinal neovessels on histology. Projection artifact removal based on 2-dimensional vessel-shape estimation and Gaussian blur filter demonstrated their potential value for further use in OCTA decorrelation signal processing.

Incidence and risk of advanced age-related macular degeneration in eyes with drusenoid pigment epithelial detachment

To investigate the incidence and risk of advanced age-related macular degeneration (AMD), including geographic atrophy (GA) and macular neovascularization (MNV), in eyes with drusenoid pigment epithelial detachment (PED). Eighty-five eyes with drusenoid PED from 85 patients (77.2 ± 7.0 years, male/female: 44/41) were included in this study. Patients were followed up every 1–3 months via spectral-domain optical coherence tomography (SD-OCT) and color fundus photography. If exudation was observed on SD-OCT, fluorescein and indocyanine green angiography were performed to confirm the MNV subtype accordingly. The maximum follow-up period was 60 months. During the study period, GA developed in 8 eyes while MNV also developed in 8 eyes. The Kaplan–Meier estimator revealed that the cumulative incidence for 60 months was 17.9% and 12.2% for GA and MNV, respectively. In eyes developing MNV, retinal angiomatous proliferation was the most common. Cox regression analysis revealed that baseline PED width was the only factor associated with advanced AMD. (p = 0.0026, Cox regression analysis). The 5-year cumulative incidence of advanced AMD, including GA and MNV, was approximately 30% in eyes with drusenoid PED among the Japanese elderly. A larger baseline PED width was the only risk factor for advanced AMD.

Histology and Clinical Lifecycle of Acquired Vitelliform Lesion, a Pathway to Advanced Age-Related Macular Degeneration

PURPOSE

To evaluate hypotheses about the role of acquired vitelliform lesion (AVL) in age-related macular degeneration pathophysiology.

DESIGN

Laboratory histology study; retrospective, observational case series.

METHODS

Two donor eyes in a research archive with AVL and age-related macular degeneration were analyzed with light and electron microscopy for AVL content at locations matched to ex vivo B-scans. A retrospective, observational clinical cohort study of 42 eyes of 30 patients at 2 referral clinics determined the frequency of optical coherence tomography features stratified by AVL fate.

RESULTS

Histologic and clinical cases showed subretinal drusenoid deposit and drusen. Ultrastructural AVL components in 2 donor eyes included retinal pigment epithelium (RPE) organelles (3%-22% of volume), outer segments (2%-10%), lipid droplets (0.2%-12%), and a flocculent material (57%-59%). Of 48 AVLs (mean follow-up 46 ± 39 months), 50% collapsed to complete RPE and outer retinal atrophy, 38% were stable, 10% resorbed, and 2% developed neovascularization. The Early Treatment Diabetic Retinopathy Study grid central subfield contained 77% of AVLs. Hyperreflective foci, ellipsoid zone disruption, and hyperreflective thickening of the RPE-basal lamina-Bruch membrane band were common at maximum AVL expansion. Collapsing and noncollapsing AVLs had different growth rates (rapid vs slow, respectively).

CONCLUSIONS

AVL deposits contain unexpectedly low levels of RPE organelles and outer segments. Subfoveal predilection, reflectivity on optical coherence tomography, hyperautofluorescence, yellow color, and growth-regression phases suggest dysregulation of lipid transfer pathways specific to cone photoreceptors and supporting cells in formation of AVL deposit, analogous to drusen and subretinal drusenoid deposit. Prediction of AVL outcomes via growth rates should be confirmed in larger clinical studies.

Multimodal assessments of drusenoid pigment epithelial detachments in the Age-Related Eye Disease Study 2 Ancillary (A2A) spectral-domain optical coherence tomography (SD-OCT) study cohort

PURPOSE

To identify features correlating with drusenoid pigment epithelial detachment (DPED) progression in the AREDS2 Ancillary (A2A) spectral-domain optical coherence tomography (SD-OCT) study cohort.

METHODS

In this retrospective analysis of a prospective longitudinal study, eyes with intermediate age-related macular degeneration (AMD) and DPEDs were followed longitudinally with annual multimodal imaging.

RESULTS

Thirty-one eyes of 25 participants (mean age 72.6 years) in the A2A AREDS2 substudy had DPED identified in color fundus images. SD-OCT inspection confirmed a sub-retinal pigment epithelium drusenoid elevation of ≥433 µm diameter in 25 (80.6%) eyes. Twenty-four of these eyes were followed longitudinally (median 4.0 years) during which 7 eyes (29.2%) underwent DPED collapse (with 3/7 further progressing to geographic atrophy), 6 (25.0%) developing neovascular AMD, and 11 (45.8%) maintaining DPED persistence without late AMD. On Kaplan-Meier analysis, mean time to DPED collapse was 3.9 years. Both DPED collapse and progression to neovascular AMD were preceded by the presence of hyperreflective foci over the DPED.

CONCLUSION

The natural history of DPED comprises: collapse - sometimes followed by the development of atrophy, vascularization followed by exudation, or DPED persistence. SD-OCT can confirm RPE elevation caused by drusenoid accumulation and facilitate the identification of high-risk features that correlate with progression.

HYPERREFLECTIVE FOCI AS IMPORTANT PROGNOSTIC INDICATORS OF PROGRESSION OF RETINITIS PIGMENTOSA

PURPOSE

To investigate the presence and clinical relevance of hyperreflective foci (HRFs) in retinitis pigmentosa.

METHODS

Seventy seven retinitis pigmentosa cases were retrospectively reviewed. The 10-mm wide cross-line macular scans in optical coherence tomography were acquired. Hyperreflective foci were classified according to the location in optical coherence tomography: outer layers within the macula (HRF-outer-central), macular border beyond the central 3 mm (HRF-outer-perifoveal), and choroid (HRF-choroidal). The visual acuity at baseline, at 12 months, and other fundus characteristics were collected.

RESULTS

The mean logMAR best-corrected visual acuity decreased from 0.59 ± 0.66 (20/78 in Snellen) to 0.74 ± 0.81 (20/106 in Snellen) in 1 year. Sixty-six (42.9%), 105 (68.2%), and 98 (63.6%) eyes were classified to HRF-outer-central, HRF-outer-perifoveal, and HRF-choroidal group, respectively. Hyperreflective foci were positively correlated with poorer vision, central macular thinning, and ellipsoid zone disruption (all P < 0.001). Worse vision was associated with older age, macular involvement, and the coexistence of two or three HRF groups (P = 0.014, 0.047, 0.019, <0.001, respectively). Hyperreflective foci developed more frequently in patients with thick choroid than in those with thin choroid. The coexistence of three HRF groups was correlated with quicker visual deterioration (P = 0.034).

CONCLUSION

Hyperreflective foci are common in retinitis pigmentosa and can be a negative prognostic indicator of macular thickness and visual preservation. Thick choroid was associated with all groups of HRFs, especially HRF-choroidal.

Autofluorescent Organelles Within the Retinal Pigment Epithelium in Human Donor Eyes With and Without Age-Related Macular Degeneration

Purpose

Human retinal pigment epithelium (RPE) cells contain lipofuscin, melanolipofuscin, and melanosome organelles that impact clinical autofluorescence (AF) imaging. Here, we quantified the effect of age-related macular degeneration (AMD) on granule count and histologic AF of RPE cell bodies.

Methods

Seven AMD-affected human RPE-Bruch's membrane flatmounts (early and intermediate = 3, late dry = 1, and neovascular = 3) were imaged at fovea, perifovea, and near periphery using structured illumination and confocal AF microscopy (excitation 488 nm) and compared to RPE-flatmounts with unremarkable macula (n = 7, >80 years). Subsequently, granules were marked with computer assistance, and classified by their AF properties. The AF/cell was calculated from confocal images. The total number of granules and AF/cell was analyzed implementing a mixed effect analysis of covariance (ANCOVA).

Results

A total of 152 AMD-affected RPE cells were analyzed (fovea = 22, perifovea = 60, and near-periphery = 70). AMD-affected RPE cells showed increased variability in size and a significantly increased granule load independent of the retinal location (fovea: P = 0.02, perifovea: P = 0.04, and near periphery: P < 0.01). The lipofuscin fraction of total organelles decreased and the melanolipofuscin fraction increased in AMD, at all locations (especially the fovea). AF was significantly lower in AMD-affected cells (fovea: <0.01, perifovea: <0.01, and near periphery: 0.02).

Conclusions

In AMD RPE, lipofuscin was proportionately lowest in the fovea, a location also known to be affected by accumulation of soft drusen and preservation of cone-mediated visual acuity. Enlarged RPE cell bodies displayed increased net granule count but diminished total AF. Future studies should also assess the impact on AF imaging of RPE apical processes containing melanosomes.

Long-Term Analysis of Clinical Features and Treatment Outcomes of Inflammatory Choroidal Neovascularization

PURPOSE

To investigate the long-term clinical features and treatment outcomes of patients with inflammatory choroidal neovascularization (CNV) treated with intravitreal anti-vascular endothelial growth factor (anti-VEGF).

DESIGN

Retrospective, interventional, consecutive case series.

METHODS

Sixty-five eyes of 65 patients with inflammatory CNV treated with anti-VEGF injections and followed up at least 12 months were included. Retrospective chart review was conducted at a single tertiary referral center.

RESULTS

Study participants were followed up for 60.6 ± 42.8 (range, 16-160) months. Mean age was 33.4 ± 10.8 years, and mean refractive error was -3.94 ± 1.35 D in spherical equivalent. Final best-corrected visual acuity (BCVA) was 0.21 ± 0.20 logMAR after treatment. Patients were treated with bevacizumab (76.9%), ranibizumab (4.6%), aflibercept (3.1%), and drug combinations (15.4%). Systemic corticosteroid or immunosuppressant use was not correlated with visual outcome, required number of anti-VEGF injections, and recurrence. Commonly occurring optical coherence tomography (OCT) features included ellipsoid zone disruption, choroidal hypertransmission, retinal pigment epithelium atrophy or absence (RPEA), intraretinal hyperreflective foci (HRF), choroidal vessel engorgement, focal choroidal excavation, and irregular vascular loops (on OCT angiography). RPEA after treatment (β = 0.238, P = .036) and BCVA (β = 0.267, P = .029) showed significant correlation with final BCVA. A total of 28 patients (43.1%) experienced recurrence; intraretinal HRF after treatment was the single risk factor for recurrence (odds ratio = 2.712, P = .031).

CONCLUSIONS

Inflammatory CNV recurrence showed higher rates over time after anti-VEGF treatment than previously reported, even though the overall visual outcome was good. Baseline BCVA and RPEA after treatment are significant predictors for visual outcome. Intraretinal HRF after anti-VEGF treatment suggests the potential risk of recurrence.

Histology and clinical imaging lifecycle of black pigment in fibrosis secondary to neovascular age-related macular degeneration

PURPOSE

Melanotic cells with large spherical melanosomes, thought to originate from retinal pigment epithelium (RPE), are found in eyes with neovascular age-related macular degeneration (nvAMD). To generate hypotheses about RPE participation in fibrosis, we correlate histology to clinical imaging in an eye with prominent black pigment in fibrotic scar secondary to nvAMD.

METHODS

Macular findings in a white woman with untreated inactive subretinal fibrosis due to nvAMD in her right eye were documented over 9 years with color fundus photography (CFP), fundus autofluorescence (FAF) imaging, and optical coherence tomography (OCT). After death (age 90 years), this index eye was prepared for light and electron microscopy to analyze 7 discrete zones of pigmentation in the fibrotic scar. In additional donor eyes with nvAMD, we determined the frequency of black pigment (n = 36 eyes) and immuno-labeled for retinoid, immunologic, and microglial markers (RPE65, CD68, Iba1, TMEM119; n = 3 eyes).

RESULTS

During follow-up of the index eye, black pigment appeared and expanded within a hypoautofluorescent fibrotic scar. The blackest areas correlated to melanotic cells (containing large spherical melanosomes), some in multiple layers. Pale areas had sparse pigmented cells. Gray areas correlated to cells with RPE organelles entombed in the scar and multinucleate cells containing sparse large spherical melanosomes. In 94% of nvAMD donor eyes, hyperpigmentation was visible. Certain melanotic cells expressed some RPE65 and mostly CD68. Iba1 and TMEM119 immunoreactivity, found both in retina and scar, did not co-localize with melanotic cells.

CONCLUSION

Hyperpigmentation in CFP results from both organelle content and optical superimposition effects. Black fundus pigment in nvAMD is common and corresponds to cells containing numerous large spherical melanosomes and superimposition of cells containing sparse large melanosomes, respectively. Melanotic cells are molecularly distinct from RPE, consistent with a process of transdifferentiation. The subcellular source of spherical melanosomes remains to be determined. Detailed histology of nvAMD eyes will inform future studies using technologies for spatially resolved molecular discovery to generate new therapies for fibrosis. The potential of black pigment as a biomarker for fibrosis can be investigated in clinical multimodal imaging datasets.

Significance of Hyperreflective Foci as an Optical Coherence Tomography Biomarker in Retinal Diseases: Characterization and Clinical Implications

Hyperreflective foci (HRF) is a term coined to depict hyperreflective dots or roundish lesions within retinal layers visualized through optical coherence tomography (OCT). Histopathological correlates of HRF are not univocal, spacing from migrating retinal pigment epithelium cells, lipid-laden macrophages, microglial cells, and extravasated proteinaceous or lipid material. Despite this, HRF can be considered OCT biomarkers for disease progression, treatment response, and prognosis in several retinal diseases, including diabetic macular edema, age-related macular degeneration (AMD), retinal vascular occlusions, and inherited retinal dystrophies. The structural features and topographic location of HRF guide the interpretation of their significance in different pathological conditions. The presence of HRF less than 30 μm with reflectivity comparable to the retinal nerve fiber layer in the absence of posterior shadowing in diabetic macular edema indicates an inflammatory phenotype with a better response to steroidal treatment. In AMD, HRF overlying drusen are associated with the development of macular neovascularization, while parafoveal drusen and HRF predispose to macular atrophy. Thus, HRF can be considered a key biomarker in several common retinal diseases. Their recognition and critical interpretation via multimodal imaging are vital to support clinical strategies and management.

Retinal Progression Biomarkers of Early and Intermediate Age-Related Macular Degeneration

Early and intermediate AMD patients represent a heterogeneous population with an important but variable risk of progression to more advanced stages of the disease. The five-year progression from early and intermediate AMD to late disease is known to range from 0.4% to 53%. This wide variation explains the particular interest in searching predictive AMD biomarkers. Clinical parameters such as drusen size, presence of pigmentary abnormalities, and fellow eye status were, traditionally, the more important predictive elements. Multimodal retinal assessment (Color Fundus Photography, Optical Coherence Tomography, Optical Coherence Angiography and Fundus Autofluorescence) is providing new and accurate image biomarkers, useful in research and in daily practice. If individual progression risk could be anticipated, then management plans should be adapted accordingly, considering follow-up intervals and therapeutic interventions. Here, we reviewed the most important image progression biomarkers of early and intermediate AMD with relevant interest in clinical practice.

FOVEAL OUTER RETINAL HYPERREFLECTIVITY: A NOVEL OPTICAL COHERENCE TOMOGRAPHY FINDING IN IDIOPATHIC MULTIFOCAL CHOROIDITIS

PURPOSE

To describe three patients with idiopathic multifocal choroiditis (MFC) who showed foci of foveal outer retinal hyperreflectivity on optical coherence tomography.

METHODS

Retrospective review of electronic health records and multimodal imaging from three patients with MFC.

RESULTS

Three consecutive white patients with MFC (two male and one female) presented with unilateral foveal outer retinal hyperreflectivity in the eye with active MFC. In all cases, the lesions persisted for at least 1 month. Optical coherence tomography demonstrated finger-like projections of hyperreflectivity extending from the retinal pigment epithelium and through disrupted interdigitation and ellipsoid zones into the outer nuclear layer, with some aspects of the lesions reaching the inner limiting membrane. Visual recovery varied in the three affected eyes.

CONCLUSION

Foveal outer retinal hyperreflectivity is a novel optical coherence tomography finding in eyes with active MFC. Additional studies will be required to address the prevalence and prognostic importance of foveal outer retinal hyperreflectivity.

Hyperreflective foci in the choroid of normal eyes

PURPOSE

To investigate hyperreflective choroidal foci (HCF) using en face swept-source optical coherence tomography (SS-OCT) and determine the factors that contribute to the distribution of HCF in normal eyes.

METHODS

In this retrospective study, we included healthy eyes with a normal fundus. HCF were defined as hyperreflective spots on en face SS-OCT images. The number, mean area, total area, and circularity of the HCF were compared with various choroid measurements obtained using SS-OCT, SS-OCT angiography, and fundus photography.

RESULTS

We investigated 51 eyes from 51 patients. The mean patient age was 56.0 ± 14.7 years, and 32 (62.7%) were female. The number and total area of HCF did not differ between the female and male patients and the right and left eyes. The number of HCF was correlated with the stromal area of the choroid (r = 0.291, P = 0.040) and subfoveal choroidal vascularity index (r =  - 0.364, P = 0.009). The total area of HCF was correlated with the stromal area of the choroid (r = 0.283, P = 0.045). However, the number and total area of HCF were not correlated with age, degree of macular tessellation, subfoveal choroidal thickness, and choriocapillaris vascular density and flow void area.

CONCLUSION

HCF were observed in normal eyes, and their distribution was associated with the underlying stromal component of the choroid. The results of this study can be used as a reference for determining abnormal hyperreflective foci in the choroid of the eyes with various diseases.

Characteristics and Associated Factors of Flat Irregular Pigment Epithelial Detachment With Choroidal Neovascularization in Chronic Central Serous Chorioretinopathy

Purpose: Flat irregular pigment epithelial detachment (FIPED) in chronic central serous chorioretinopathy (CSC) is strongly associated with type 1 choroidal neovascularization (CNV). The present study aimed to describe the multimodal imaging characteristics of FIPED in patients with chronic CSC and investigate the factors associated with vascularized FIPED.

Methods: We included 55 chronic CSC eyes with vascularized FIPED (47 patients) and 55 chronic CSC eyes with avascular FIPED from age-matched patients (47 patients). None of the included eyes had a history of previous treatment with anti-vascular endothelial growth factor, photodynamic therapy, focal laser, or vitrectomy. The demographic and multimodal imaging data were reviewed. The location, angiography features, height and width, presence of retinal pigment epithelium (RPE) aggregations, RPE thickness, and choroid status of the FIPED area were compared between the groups.

Results: The mean age of the included chronic CSC patients was 54.3 ± 7.8 years (range: 33–72 years), and 85.1% were male. Vascularized FIPED eyes had a larger width (1,556.4 ± 731.6 vs. 931.1 ± 486.2 μm, p < 0.001), larger subfoveal RPE thickness (33.4 ± 15.3 vs. 26.3 ± 6.6 μm, p = 0.004), larger maximum RPE thickness of the FIPED area (46.3 ± 20.5 vs. 31.5 ± 8.3 μm, p < 0.001), and more RPE aggregations in the FIPED area (94.5 vs. 54.5%, p < 0.001) than avascular FIPED eyes. RPE aggregations in the FIPED area were an independent factor strongly associated with vascularized FIPED (OR = 7.922, 95% CI = 1.346–46.623, p = 0.022).

Conclusion: FIPED with a larger width and RPE thickening may suggest the presence of an underlying type 1 CNV. FIPED with RPE aggregations had an increased occurrence of neovascularization in chronic CSC.

Progressive Dysmorphia of Retinal Pigment Epithelium in Age-Related Macular Degeneration Investigated by Fluorescence Lifetime Imaging

Purpose

The purpose of this study was to observe changes of the retinal pigment epithelium (RPE) on the transition from dysmorphia to atrophy in age-related macular degeneration (AMD) by fluorescence lifetime imaging ophthalmoscopy (FLIO).

Methods

Multimodal imaging including color fundus photography (CFP), optical coherence tomography (OCT), fundus autofluorescence (FAF) imaging, and FLIO was performed in 40 eyes of 37 patients with intermediate AMD and no evidence for geographic atrophy or macular neovascularization (mean age = 74.2 ± 7.0 years). Twenty-three eyes were followed for 28.3 ± 18.3 months. Seven eyes had a second follow-up after 46.6 ± 9.0 months. Thickened RPE on OCT, hyperpigmentation on CFP, hyper-reflective foci (HRF) on OCT, attributed to single or clustered intraretinal RPE, were identified. Fluorescence lifetimes in two spectral channels (short-wavelength spectral channel [SSC] = 500–560 nm, long-wavelength spectral channel [LSC] = 560–720 nm) as well as emission spectrum intensity ratio (ESIR) of the lesions were measured by FLIO.

Results

As hyperpigmented areas form and RPE migrates into the retina, FAF lifetimes lengthen and ESRI of RPE cells increase. Thickened RPE showed lifetimes of 256 ± 49 ps (SSC) and 336 ± 35 ps (LSC) and an ESIR of 0.552 ± 0.079. For hyperpigmentation, these values were 317 ± 68 ps (p < 0.001), 377 ± 56 ps (P < 0.001), and 0.609 ± 0.081 (P = 0.001), respectively, and for HRF 337 ± 79 ps (P < 0.001), 414 ± 50 ps (P < 0.001), and 0.654 ± 0.075 (P < 0.001).

Conclusions

In the process of RPE degeneration, comprising different steps of dysmorphia, hyperpigmentation, and migration, lengthening of FAF lifetimes and a hypsochromic shift of emission spectra can be observed by FLIO. Thus, FLIO might provide early biomarkers for AMD progression and contribute to our understanding of RPE pathology.

COMPARISON OF SPECTRALIS AND CIRRUS OPTICAL COHERENCE TOMOGRAPHY FOR THE DETECTION OF INCOMPLETE AND COMPLETE RETINAL PIGMENT EPITHELIUM AND OUTER RETINAL ATROPHY

PURPOSE

To evaluate and compare the detection of incomplete and complete retinal pigment epithelial and outer retinal atrophy (iRORA and cRORA) using Spectralis and Cirrus optical coherence tomography (OCT) devices.

METHODS

Subjects with late age-related macular degeneration were imaged on the same day with Spectralis and Cirrus OCT. Two, masked, independent, and experienced retina specialist graders evaluated each case for the presence of cRORA and iRORA lesions.

RESULTS

A significantly higher number of lesions were observed using Spectralis compared with Cirrus (239 vs. 226 and 223 vs. 209). Higher number of iRORA lesions were identified with Spectralis (105 vs. 90 and 96 vs. 82), and no significant difference was observed between devices for cRORA lesions (134 vs. 136 and 128 vs. 126). When considering the presence or absence of iRORA or cRORA, the agreement between devices for both graders was excellent for cRORA and good for iRORA.

CONCLUSION

Spectralis and Cirrus OCT identified a similar number of cRORA lesions, although more iRORA lesions could be detected with Spectralis OCT. These findings may have implications for developing acquisition protocols for trials based on the intended atrophy targets and highlight the importance of using a consistent OCT instrument across a study.

Hypoxic and osmotic expression of Kir2.1 potassium channels in retinal pigment epithelial cells: Contribution to vascular endothelial growth factor expression

Retinal pigment epithelial (RPE) cells express different subtypes of inwardly rectifying potassium (Kir) channels. We investigated whether human and rat RPE cells express genes of strongly rectifying Kir2 channels. We also determined the hypoxic and hyperosmotic regulation of Kir2.1 gene expression in cultured human RPE cells and the effects of siRNA-mediated knockdown of Kir2.1 on VEGFA expression, VEGF secretion, proliferation, and viability of the cells. Extracellular hyperosmolarity was induced by addition of NaCl or sucrose. Hypoxia and chemical hypoxia were produced by cell culture in 0.25% O₂ and addition of CoCl₂, respectively. Gene expression levels were evaluated by real-time RT-PCR. Rat RPE cells contained Kir2.1, Kir2.2, Kir2.3, and Kir2.4 gene transcripts while human RPE cells contained Kir2.1, Kir2.2, and Kir2.4 transcripts. Immunocytochemical data may suggest that Kir2.1 protein in cultured human cells is expressed in both perinuclear and plasma membranes. Kir2.1 gene expression and Kir2.1 protein level in human cells increased under hypoxic and hyperosmotic conditions. The expression of the Kir2.1 gene was mediated in part by diverse intracellular signal transduction pathways and transcription factor activities under both conditions; the hyperosmotic, but not the CoCl₂-induced Kir2.1 gene expression was dependent on intracellular calcium signaling. Autocrine/paracrine activation of purinergic receptors contributed to Kir2.1 gene expression under hyperosmotic (P2Y₁, P2Y₂, P2X₇) and CoCl₂-induced conditions (P2Y₂, P2X₇). Exogenous VEGF, TGF-β1, and blood serum decreased Kir2.1 gene expression. Inhibition of VEGF receptor-2 increased the Kir2.1 gene expression under control conditions and in CoCl₂-simulated hypoxia, and decreased it under high NaCl conditions. Knockdown of Kir2.1 by siRNA inhibited the CoCl₂-induced and hyperosmotic transcription of the VEGFA gene and caused a delayed decrease of the constitutive VEGFA gene expression while VEGF protein secretion was not altered. Kir2.1 knockdown stimulated RPE cell proliferation under control and hyperosmotic conditions without affecting cell viability. The data indicate that Kir2.1 channel activity is required for the expression of the VEGFA gene and inhibits the proliferation of RPE cells. Under control and hypoxic conditions, the extracellular VEGF level may regulate the production of VEGF via its inhibitory effect on the Kir2.1 gene transcription; this feedback loop may prevent overproduction of VEGF.

[Transformation of choroidal nevus into melanoma]

The risk of choroidal melanoma developing from choroidal nevus (CN) varies in range of 0.78-7%. Absence of a common terminology and distinct diagnostic criteria characterizing small melanoma de novo and unusual CN often complicates treatment choice and patient prognosis.

PURPOSE

To study the clinical features and the role of visualization methods in the diagnosis of CN transformation into melanoma.

MATERIAL AND METHODS

The study analyzes the clinical picture and visualization results of 11 patients with initial diagnosis of «choroidal nevus» (n=3) and «suspicious choroidal nevus» (n=8).

RESULTS AND DISCUSSION

Examination and continued observation revealed 7 patients to have melanoma that had developed from CN (2 of them confirmed with histological studies). The time before CN transformed into melanoma varied between 4 and 13 years, with median 5 [4; 12] years. Two patients were diagnosed with primary melanoma (melanoma de novo), two other patients - with suspicious CN. In progressive CN transforming into melanoma, visual impairments occurred between 6 months and 13 years in 6 out of 7 patients. Initial prominence of suspicious CN at the first visit was 1.9±0.68 mm (0.9 mm to 2.67 mm). The characteristic features of suspicious CN transforming into initial melanoma are: 1) asymmetric shape of the edges of expanded choroidal complex; 2) presence of areas of damaged choriocapillaris layer, direct and indirect signs of loss of integrity of the Bruch's membrane; 3) areas of accumulation of moderately hyperreflective subretinal exudate; 4) presence of intraretinal hyperreflective inclusions. The signs distinguishing primary choroidal melanoma from melanoma that had developed from CN are: 1) absence of areas with tomography pattern characteristic of nevi; 2) more pronounced asymmetry of the shape of edges, compared to melanoma developed from CN; 3) presence of cysts in larger tumors, compared to melanoma developed from CN.

CONCLUSION

All patients with CN should be regularly followed up by an ophthalmologist.

Assessment of macular function in patients with non-vascularized pigment epithelial detachment

Non-vascularized pigment epithelial detachments (PED) are usually associated with dry age-related macular degeneration (AMD). In this study, we aimed to investigate the correlation between visual function and morphologic parameters. Seventeen eyes of eleven patients with non-vascularized AMD were enrolled. In addition to conventional optical coherence tomography (OCT), polarization-sensitive optical coherence tomography (PS-OCT) measurements were performed by evaluating the regularity of retinal pigment epithelium (RPE) entropy within the PED area. Retinal sensitivity was measured with MP-3 microperimetry, and retinal sensitivities within (RSin) and outside (RSout) the PED area were calculated. The relationship between OCT parameters and visual function was analyzed. As a result, there was a significant difference between the RSin and RSout (p < 0.001, Wilcoxon signed rank test). Moreover, RSin was significantly related to logMAR VA (p = 0.033, linear mixed model). The regularity of RPE entropy was significantly related to visual acuity and RSin (p = 0.00038, p = 0.031, linear mixed model), although neither the height nor area of PED correlated with visual function. Our results suggest that retinal sensitivity is significantly deteriorated within the PED area and RPE entropy measured with PS-OCT was closely related to visual function in eyes with non-vascularized PED.

Hyperreflective Foci, Optical Coherence Tomography Progression Indicators in Age-Related Macular Degeneration, Include Transdifferentiated Retinal Pigment Epithelium

Purpose

By optical coherence tomography (OCT) imaging, hyperreflective foci (HRF) indicate progression risk for advanced age-related macular degeneration (AMD) and are in part attributable to ectopic retinal pigment epithelium (RPE). We hypothesized that ectopic RPE are molecularly distinct from in-layer cells and that their cross-retinal course follows Müller glia.

Methods

In clinical OCT (61 eyes, 44 patients with AMD, 79.4 ± 7.7 years; 29 female; follow-up = 4.7 ± 0.9 years), one HRF type, RPE plume (n = 129 in 4 morphologies), was reviewed. Twenty eyes of 20 donors characterized by ex vivo OCT were analyzed by histology (normal, 4; early/intermediate AMD, 7; geographic atrophy, 6; neovascular AMD, 3). Cryosections were stained with antibodies to retinoid (RPE65, CRALPB) and immune (CD68, CD163) markers. In published RPE cellular phenotypes, red immunoreactivity was assessed semiquantitatively by one observer (none, some cells, all cells).

Results

Plume morphology evolved over time and many resolved (40%). Trajectories of RPE plume and cellular debris paralleled Müller glia, including near atrophy borders. RPE corresponding to HRF lost immunoreactivity for retinoid markers and gained immunoreactivity for immune markers. Aberrant immunoreactivity appeared in individual in-layer RPE cells and extended to all abnormal phenotypes. Müller glia remained CRALBP positive. Plume cells approached and contacted retinal capillaries.

Conclusions

HRF are indicators not predictors of overall disease activity. Gain and loss of function starts with individual in-layer RPE cells and extends to all abnormal phenotypes. Evidence for RPE transdifferentiation, possibly due to ischemia, supports a proposed process of epithelial–mesenchyme transition. Data can propel new biomarkers and therapeutic strategies for AMD.

OCT Biomarkers in Neovascular Age-Related Macular Degeneration: A Narrative Review

Age-related macular degeneration (AMD) is the leading cause of legal blindness in elderly people. Neovascular AMD (nAMD) is responsible for the majority of cases of severe visual loss in eyes with AMD. Optical coherence tomography (OCT) is the most widely used technology for the diagnosis and follow-up of nAMD patients, which is widely used to study and guide the clinical approach, as well as to predict and evaluate treatment response. The aim of this review is to describe and analyze various structural OCT-based biomarkers, which have practical value during both initial assessment and treatment follow-up of nAMD patients. While central retinal thickness has been the most common and one of the first OCT identified biomarkers, today, other qualitative and quantitative biomarkers provide novel insight into disease activity and offer superior prognostic value and better guidance for tailored therapeutic management. The key importance of retinal fluid compartmentalization (intraretinal fluid, subretinal fluid, and subretinal pigment epithelium (RPE) fluid) will be discussed firstly. In the second part, the structural alterations of different retinal layers in various stages of the disease (photoreceptors layer integrity, hyperreflective dots, outer retinal tubulations, subretinal hyperreflective material, and retinal pigment epithelial tears) will be analyzed in detail. The last part of the review will focus on how alterations of the vitreoretinal interface (vitreomacular adhesion and traction) and of the choroid (sub-RPE hyperreflective columns, prechoroidal clefts, choroidal caverns, choroidal thickness and choroidal volume, and choroidal vascular index) interact with nAMD progression. OCT technology is evolving very quickly, and new retinal biomarkers are continuously described. This up-to-date review article provides a comprehensive description on how structural OCT-based biomarkers provide a valuable tool to monitor the progression of the disease and the treatment response in nAMD patients. Thus, in this perspective, clinicians will be able to allocate hospital resources in the best possible way and tailor treatment to the individual patient's needs.

Exploring the choroidal vascular labyrinth and its molecular and structural roles in health and disease

The choroid is a key player in maintaining ocular homeostasis and plays a role in a variety of chorioretinal diseases, many of which are poorly understood. Recent advances in the field of single-cell RNA sequencing have yielded valuable insights into the properties of choroidal endothelial cells (CECs). Here, we review the role of the choroid in various physiological and pathophysiological mechanisms, focusing on the role of CECs. We also discuss new insights regarding the phenotypic properties of CECs, CEC subpopulations, and the value of measuring transcriptomics in primary CEC cultures derived from post-mortem eyes. In addition, we discuss key phenotypic, structural, and functional differences that distinguish CECs from other endothelial cells such as retinal vascular endothelial cells. Understanding the specific clinical and molecular properties of the choroid will shed new light on the pathogenesis of the broad clinical range of chorioretinal diseases such as age-related macular degeneration, central serous chorioretinopathy and other diseases within the pachychoroid spectrum, uveitis, and diabetic choroidopathy. Although our knowledge is still relatively limited with respect to the clinical features and molecular pathways that underlie these chorioretinal diseases, we summarise new approaches and discuss future directions for gaining new insights into these sight-threatening diseases and highlight new therapeutic strategies such as pluripotent stem cell‒based technologies and gene therapy.

Correlation of in vivo/ex vivo imaging of the posterior eye segment

BACKGROUND

For an understanding of the pathology of retinal diseases, direct comparisons of high-resolution in vivo retinal imaging and ex vivo histological preparations are desirable.

MATERIAL AND METHODS

Multimodal in vivo and ex vivo imaging of a human donor eye with secondary alterations showing atrophic retina due to central retinal arterial occlusion. The subsequent correlation with the histological examination was carried out on identical tissue localizations.

RESULTS

Appropriate custom-built retinal imaging devices facilitate in vivo and ex vivo correlations and the examination of human eye tissue and acquisition of retinal images, e.g. SD-OCT. The precise alignment of the tissue enables a histological analysis on identical sites.

CONCLUSION

The direct correlation of clinical in vivo imaging with ex vivo imaging including histopathology can further enhance our understanding in the pathogenesis of retinal diseases; however, the proposed method is currently limited due to restricted availability of human donor tissue.

Pentosan polysulfate maculopathy

Pentosan polysulfate sodium (PPS), a semisynthetic sulfated polysaccharide, is the only FDA-approved oral therapy for interstitial cystitis. Recent studies have described a progressive, vision-threatening macular condition associated with long-term PPS use. We reviewed all publications concerning PPS maculopathy to consolidate known clinical features and to evaluate the strength of this association. Current literature supports a strong dose-dependent association between PPS exposure and a progressive maculopathy impacting the retinal pigment epithelium (RPE) and RPE-photoreceptor interface that may worsen even after drug cessation. Initial symptoms may include prolonged dark adaptation and difficulty reading with relative visual acuity preservation. Fundus examination often shows macular pigment clumps corresponding to lesions of focal RPE thickening. Fundus autofluorescence most clearly depicts the condition, with a distinctive pattern of hypo- and hyperautofluorescent spots in the posterior pole that sometimes extends to the retinal periphery. Many cases also show a characteristic peripapillary hypoautofluorescent halo. Near infrared reflectance may aid in early detection. RPE atrophy, cystoid macular edema, and macular neovascularization may also occur, potentially resulting in loss of central acuity. This newly described association implies significant public health risk. Ophthalmologists should screen PPS users with multimodal retinal imaging, and prescribers should minimize dose and duration of PPS use.