High-Resolution Optical Coherence Tomography Visualizes Posterior Vitreous Lamellar Architecture in Eyes With Chronic Central Serous Chorioretinopathy

Abstract

Purpose

High-resolution optical coherence tomography (HighRes-OCT) enables in vivo visualization of microstructural features that are not accessible with conventional clinical OCT systems. Using this capability, we investigated posterior vitreous microarchitecture in eyes with chronic central serous chorioretinopathy (CSC) and healthy individuals.

Methods

HighRes-OCT imaging (axial resolution approximately 3 µm) was performed in 20 patients with chronic CSC and 20 age-matched healthy subjects. Posterior vitreous structures were qualitatively assessed for the presence of discrete lamellar patterns and compared with conventional spectral-domain OCT (SD-OCT) acquired at the same visits. Lamellar visibility was evaluated across scan orientations, and reproducibility was assessed in all CSC eyes with follow-up imaging.

Results

Distinct hyper-reflective lamellar structures within the posterior vitreous were clearly identified in 9 of 20 CSC eyes, whereas no comparable lamellar organization was observed in healthy eyes. In CSC eyes, lamellae appeared as parallel, layered bands located immediately anterior to the internal limiting membrane and were reproducible across scan orientations. These structures were not readily discernible on conventional OCT. Healthy eyes showed relatively homogeneous vitreous reflectivity, although faint linear structures were occasionally observed.

Conclusions

HighRes-OCT enables in vivo visualization of posterior vitreous lamellar microstructures that are not readily discernible with conventional clinical OCT. The preferential detection of these structures in eyes with chronic CSC suggests disease-associated alterations in vitreous matrix organization and highlights a previously underexplored dimension of vitreous imaging.

Translational Relevance

Visualization of vitreous microarchitecture using HighRes-OCT may provide a new translational imaging window to study disease-related vitreous remodeling and its relationship to retinal pathology.

Introduction

The vitreous body plays a central role in ocular biomechanics, molecular homeostasis, and immune regulation,^1–3 yet its detailed microarchitecture has remained largely inaccessible to in vivo imaging. Early ultrastructural studies have demonstrated that the vitreous is composed of an organized network of collagen fibrils rather than a homogeneous gel, underscoring the presence of a defined microarchitecture that has been difficult to visualize in vivo.⁴ Although predominantly composed of water, the vitreous contains a sparse but highly organized network of collagen fibrils: primarily type II, with contributions from types V/XI and IX, embedded within a hyaluronan-rich matrix, together forming a three-dimensional extracellular matrix.^5–7

Changes in collagen organization have been suggested to be associated with aging, oxidative stress, posterior vitreous detachment, and retinal disease.^2,3,8 However, despite its potential relevance as a sensor of intraocular or systemic molecular alterations, the vitreous has traditionally been viewed as only sparsely structured on clinical optical coherence tomography (OCT), as most of its fibrillar components remain below the resolution of conventional imaging.

Beyond ultrastructural organization, histological and anatomic studies have further characterized the vitreous body as a regionally organized structure with distinct vitreomacular relationships. Detailed descriptions of vitreous anatomy have emphasized the close spatial interaction between the vitreous and the retina.⁹ However, most of these insights have been derived from ex vivo observations or indirect imaging approaches, and direct in vivo visualization of vitreous microarchitecture has remained challenging.

OCT has transformed the visualization of retinal anatomy, yet its capability to resolve vitreous microstructure remains limited. Conventional spectral-domain OCT (SD-OCT), with an axial resolution of approximately 7 µm, typically depicts the posterior vitreous as a diffuse, low-contrast region without discernible substructure. Swept-source OCT has been applied to vitreous imaging primarily to improve imaging depth and signal penetration^10,11; however, this advantage is typically achieved at the expense of axial resolution. Techniques such as vitreous-enhanced imaging with SD-OCT shift the focal plane anteriorly to increase vitreous contrast^12–16 but reduce retinal resolution and still lack the ability to resolve fine collagen architecture. As a result, the detailed organization of posterior vitreous collagen remains largely invisible in routine clinical practice.

The proprietary high-resolution OCT system “HighRes-OCT” (Heidelberg Engineering, Heidelberg, Germany) enabled by a broader bandwidth centered at 850 nm and delivering an axial resolution of approximately 3 µm,¹⁷ has been shown to delineate retinal microstructures with substantially greater detail than conventional SD-OCT.^17–29 This enhanced resolution allows visualization of fine anatomic features within the retina that are otherwise not discernible with conventional OCT. Whereas HighRes-OCT has demonstrated its capability to resolve retinal microarchitecture,^18–21 vitreoretinal interface alterations,²² and various chorioretinal pathologies^23–29 its application to the vitreous body has been minimally explored. Consequently, the prevalence, variability, and disease association of vitreous lamellar structures remain largely unknown.

Central serous chorioretinopathy (CSC) is a retinal disorder characterized by choroidal dysfunction, hydrostatic imbalance, oxidative stress, and impairment of the outer blood–retinal barrier (BRB) maintainance by tight junctions of retinal pigment epithelial (RPE) cells.³⁰ Such biochemical and biophysical disturbances may plausibly influence the extracellular matrix environment of the vitreous. In addition, because CSC frequently affects relatively younger individuals without advanced posterior vitreous detachment, it may provide a particularly suitable condition for in vivo evaluation of posterior vitreous microarchitecture. Whether in vivo high-resolution imaging can detect vitreous microstructural patterns associated with CSC has not been investigated, and the potential of vitreous architecture to reflect disease-related changes remains an open question.

Here, we use HighRes-OCT to examine posterior vitreous microstructure in patients with chronic CSC compared with healthy individuals. This exploratory, hypothesis-generating study aims to characterize the visibility and qualitative features of vitreous lamellar structures and to evaluate whether such structures may reflect disease-related alterations in vitreous matrix organization. By providing the first systematic in vivo observations of vitreous lamellae using a 3-µm resolution OCT system, this work highlights an emerging dimension of vitreous imaging and motivates future studies to clarify its biological and clinical relevance.

Methods

This exploratory cross-sectional imaging study was conducted at the Department of Ophthalmology, University Hospital Schleswig-Holstein, Campus Lübeck. The study protocol was approved by the Institutional Review Board of the University of Lübeck and adhered to the tenets of the Declaration of Helsinki. Written informed consent was obtained from all participants prior to enrollment.

Participants

HighRes-OCT imaging was performed in 20 patients with chronic CSC and 20 healthy subjects without ocular disease or systemic conditions with known ocular involvement. Patients with CSC were consecutively recruited from the outpatient clinic during the study period. Exclusion criteria included prior vitrectomy, significant media opacity, and advanced posterior vitreous detachment. CSC was diagnosed based on clinical examination and multimodal imaging, including SD-OCT. Participants ranged in age from 31 to 62 years (median = 49 years), whereas healthy subjects were age-matched (31–65 years, median = 53 years) and confirmed to have no retinal pathology. In patients with unilateral CSC, the affected eye was included. In cases with bilateral CSC findings, the eye with more clearly identifiable chronic CSC changes and sufficient image quality was selected for analysis.

High-Resolution OCT Imaging

All imaging was performed using HighRes-OCT (Heidelberg Engineering, Heidelberg, Germany), which provides an axial resolution of approximately 3 µm using an 850 nm center wavelength and 130 nm bandwidth, with an A-scan acquisition frequency of 85 kilohertz (kHz). Macular lateral raster volume scans covering a 20 degrees × 20 degrees area were acquired using 49 B-scans with a scan spacing of 120 µm. Automatic real-time (ART) averaging was set to 50 frames to increase signal stability. Image acquisition was performed by an experienced ophthalmologist using consistent acquisition settings to minimize inter-session variability. Scan locations were standardized using predefined fixation targets (central and superior or inferior fixation points). Brightness and contrast settings were kept constant throughout image acquisition and qualitative analysis. The device-derived Q-value, reflecting the signal-to-noise ratio and overall OCT image quality, was used as the image quality index. Because the premacular bursa adjacent to the fovea does not contain appreciable fibrillar vitreous structures, vitreous features were evaluated primarily near the superior or inferior vascular arcades. Images were acquired using the prototype software version SP-1904. Comparable scans using the conventional Spectralis OCT (Heidelberg Engineering, 7-µm axial resolution) were used for qualitative comparison.

Qualitative Assessment

Vitreous lamellar structures were assessed qualitatively based on their visibility as discrete, layered hyper-reflective patterns anterior to the internal limiting membrane. For descriptive purposes, visibility was categorized as: (1) clearly recognizable lamellae, (2) weakly discernible lamellar structure, or (3) no visible lamellar pattern. This categorization was used solely to summarize observations. Vitreous lamellar visibility was independently assessed by two readers. Disagreements were resolved by consensus. For repeated HighRes-OCT examinations, the device follow-up function was used whenever available to reproduce scan locations. Exact cross-device registration between HighRes-OCT and conventional Spectralis OCT was not technically possible. In all patients, the same retinal location was re-imaged during follow-up periods ranging from 1 to 27 months (median = 14 months) to compare the appearance of the vitreous structures over time.

Statistical Analysis

Exploratory statistical analysis was performed using Fisher's exact test to compare the frequency of lamellar visibility between CSC eyes and healthy controls. A P value < 0.05 was considered statistically significant.

Results

Visualization of Posterior Vitreous Lamellar Structures

Distinct hyper-reflective lamellar structures within the posterior vitreous were identified in a subset of eyes with chronic CSC using HighRes-OCT (Fig. 1a). Such lamellar structures were substantially less discernible on conventional SD-OCT acquired at the same visit and retinal locations (Fig. 1b). On conventional OCT images, the posterior vitreous appeared as a diffuse region of low contrast without discernible internal stratification, irrespective of CSC status. Observed lamellar vitreous structures in HighRes-OCT appeared as parallel, planar hyper-reflective bands located immediately anterior to the internal limiting membrane, in regions without posterior vitreous detachment. The lamellae extended laterally and were oriented parallel to the retinal surface. This lamellar appearance was preserved across adjacent B-scans (see Supplementary Movie S1), indicating a sheet-like three-dimensional organization rather than isolated linear opacities or focal vitreous condensations.

Figure 1.

A representative case of 31-year-old woman with chronic CSC. (a) HighRes-OCT image of the retinal and posterior vitreous. Distinct lamellar structures are clearly visible in the vitreous (asterisk), (b) Spectralis OCT image acquired on the same day at a location close to that shown in a. The lamellar vitreous structures are substantially less discernible (asterisks). (c) HighRes-OCT image acquired at a location close to that shown in a acquired approximately 15 months later. The distinct lamellar structure remains clearly visible (asterisk). (d) Spectralis OCT image acquired on the same day as c. The lamellar vitreous structures are again substantially less discernible (asterisks).

However, this distinct lamellar structure was not observed in all subjects: clearly recognizable lamellae were identified in 9 of 20 CSC eyes (45%), relatively weakly discernible lamellar structures were observed in 3 CSC eyes (15%), and no lamellar organization was detected in the remaining 8 CSC eyes (40%). Independent grading by the two readers demonstrated complete agreement for vitreous lamellar visibility classification. Within the examined patients with CSC, lamellar visibility showed no apparent association with age or sex. Variability in lamellar appearance among CSC eyes was observed despite comparable clinical diagnoses and standardized imaging protocols.

In repeated acquisitions at the same retinal location during follow-up periods ranging from 1 to 27 months (median = 14 months), minor variations in overall signal intensity were observed; however, the characteristic appearance of the lamellar structures, including the three grading features described above, remained qualitatively stable over time. One representative example is shown in Figures 1c and 1d.

In contrast, none of the healthy control eyes (0 of 20) exhibited comparably distinct lamellar patterns. Whereas faint linear or partially layered vitreous reflectivity could occasionally be observed in some healthy eyes, these findings were substantially less distinct and lacked the clearly recognizable organized lamellar configuration observed in a subset of CSC eyes on HighRes-OCT (Fig. 2). Statistical analysis revealed that lamellar visibility, defined as the presence of clearly recognizable or weakly discernible lamellar structures, was significantly more frequent in CSC eyes than in healthy controls (12/20 vs. 0/20; Fisher's exact test, P < 0.001).

Figure 2.

Representative HighRes-OCT images of patients with CSC (a–d) and healthy subjects (e–h). Left: Infrared (IR) reflectance images used for OCT imaging. Middle: B-scan image. Scan lines are indicated by light blue arrows in the IR image. Right: Magnified image of the area indicated by the square in the central figure. a: A 31-year-old woman, b: a 50-year-old man, c: a 45-year-old man, d: a 60-year-old man, e: a 31-year-old man, f: a 51-year-old woman, g: a 52-year-old woman, and h: a 62-year-old woman.

Discussion

This exploratory study demonstrates that HighRes-OCT with an axial resolution of 3 µm enables visualization of subtle lamellar structures within the posterior vitreous that are not detectable with conventional systems. Conventional SD-OCT has been limited in its ability to image the vitreous, typically visualizing only the vitreoretinal interface and larger features such as the premacular bursa or vitreoschisis, but not the internal fibrillar organization of the gel. This limitation arises from the low scattering properties of the vitreous combined with the insufficient axial resolution of standard clinical systems.

The vitreous is inherently difficult to image in vivo, and its structural organization has historically been inferred from indirect or ex vivo observations. Sebag and colleagues have emphasized that the long-standing diversity of descriptions of vitreous architecture reflects, in part, the fundamental challenge of visualizing a tissue designed to be optically transparent.³¹ In this context, the lamellar patterns observed in the present study are consistent with previous histological descriptions of vitreous collagen organization⁴; however, direct correspondence between in vivo OCT reflectivity and histological features should be interpreted with caution.

In recent years, the vitreous body has attracted renewed attention as an active and dynamic ocular compartment rather than a passive filler, particularly with the advent of enhanced vitreous imaging techniques. Studies by Spaide and colleagues have demonstrated that optimized OCT acquisition and display strategies can reveal vitreous structures that were previously underappreciated using conventional imaging approaches.^15,16 These observations have contributed to a growing recognition that subtle changes in vitreous organization may accompany, or reflect, retinal disease processes. However, despite these advances, the internal collagen microarchitecture of the posterior vitreous has remained largely inaccessible in vivo, particularly at the level of layered or lamellar organization.

Distinct layered patterns were preferentially observed in eyes with chronic CSC, suggesting that disease-associated alterations in vitreous matrix organization may increase the optical visibility of collagen architecture. The enhanced 3-µm axial resolution of HighRes-OCT appears sufficient to reveal lamellar patterns under certain conditions that would otherwise remain indistinct on conventional OCT. To the best of the authors’ knowledge, in vivo investigations directly addressing the relationship between retinal disease and vitreous collagen microstructure are scarce, and the present study provides an observation focusing on this association.

The preferential detection of lamellae in the vitreous with chronic CSC raises the possibility that retinal pathology may influence the biophysical environment of the vitreous. CSC is associated with choroidal hyperpermeability, oxidative stress, and disruption of the outer BRB.^30,32,33 The BRB compromise may alter retinal osmotic and ionic gradients, allowing plasma-derived proteins, cytokines, or electrolytes to accumulate within the subretinal and intraretinal spaces.^34,35 Such changes can secondarily modify the transretinal fluid gradients that normally drive water from the vitreous toward the choroid,² thereby influencing vitreous hydration and its colloid osmotic environment. Such changes could affect Donnan equilibrium, fibril hydration, and collagen fiber spacing,^36,37 thereby increasing refractive index contrast and making lamellar structures more conspicuous on high-resolution imaging. Oxidative or protein-mediated collagen cross-linking, which can alter fibril aggregation and optical contrast,³⁸ may also contribute to these observations. These mechanisms are consistent with current understanding of vitreous biology but remain speculative in the absence of direct biochemical measurements. To our knowledge, proteomic studies directly investigating vitreous alterations in chronic CSC have not yet been reported. However, proteomic analyses of CSC-associated subretinal fluid have demonstrated alterations in inflammatory, complement-related, extracellular matrix-associated, and lipid transport-related proteins,³⁹ suggesting that disease-related molecular changes occur within the ocular microenvironment. These findings raise the possibility that similar biochemical alterations may also affect the vitreous matrix, although this remains to be investigated directly. Furthermore, vitreous proteomic studies in other retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy, have revealed disease-specific changes involving inflammatory, oxidative stress-related, complement, and extracellular matrix pathways.⁴⁰ Together, these findings suggest that molecular remodeling of the ocular microenvironment may extend to the vitreous compartment and potentially influence the vitreous matrix. Future studies combining HighRes-OCT with aqueous humor or vitreous biochemical analyses may help clarify whether the increased visibility of lamellar structures reflects disease-related biochemical or biophysical remodeling of the vitreous matrix.

Notably, the enhanced visibility of lamellar structures was not observed uniformly across all CSC eyes. The variability observed within the CSC cohort may reflect inter-individual differences in vitreous biophysical or biochemical properties. This heterogeneity may suggest that distinct pathogenic mechanisms or molecular microenvironments exist among eyes currently classified under the clinical diagnosis of CSC, although this possibility requires further investigations.

This study has several limitations. The sample size was modest, and the analysis was qualitative, without quantitative assessment based on the statistics of collagen spacing or reflectivity. Only one disease entity was examined, and the predominantly cross-sectional study design does not permit a systematic evaluation of temporal changes, although limited longitudinal follow-up was available in a small number of cases. Additionally, HighRes-OCT signal characteristics may depend on scan angle, display intensity scaling, or individual anatomic differences, which were minimized but not eliminated by the standardized protocol.

Despite these limitations, our findings indicate that HighRes-OCT provides access to a previously underexplored dimension of vitreous collagen lamellar structure and its disease-associated alterations. The ability to visualize these microstructural features in vivo may offer new opportunities to investigate how retinal or systemic conditions affect the vitreous matrix. Future studies with larger cohorts, quantitative analysis, and multimodal correlation, including biochemical or proteomic evaluation of the vitreous, will be essential to determine the biological significance, specificity, and potential diagnostic relevance of these structures.