Unique optical coherence tomographic features in age-related macular degeneration

Subretinal transient hyporeflectivity in neovascular age-related macular degeneration and its response to a loading phase of aflibercept: PRECISE report 4

PURPOSE

To describe the prevalence of subretinal transient hyporeflectivity (STHR) in exudative neovascular age-related macular degeneration (nAMD) and its response to a loading phase of aflibercept.

METHODS

Optical coherence tomography (OCT) scans of treatment-naïve nAMD patients captured at baseline and after a loading phase of aflibercept were graded for presence of STHR, defined as a small, well-defined, round, subretinal, hyporeflective area, delimited between the ellipsoid zone (EZ) and the retinal pigmented epithelium/Bruch membrane complex. OCT parameters recorded were macular neovascularisation (MNV) subtypes, location of retinal fluids (subretinal fluid, SRF and intraretinal fluid, IRF), central retinal and choroidal thickness. Response was defined as absence of IRF and SRF. Factors associated with completely resolved STHR versus persistent STHR post-loading phase were compared.

RESULTS

2039 eyes of 1901 patients were analysed. STHR was observed in 79 eyes of 78 patients, with an estimated prevalence of 3.87% (95% CI 3.08-4.81%). STHR were seen in 44 type 1 MNV (56%), 27 with type 2 (34%), and 8 with type 3 (10%). At baseline, a total of 303 STHR were present, ranging between 1-22 per eye. The total number of STHR reduced significantly after the loading phase to 173 (p = 0.002). Complete disappearance of STHR was seen in 44 eyes (56%) and persistent STHR in the rest (44%).

CONCLUSIONS

STHR may represent a marker of low-grade exudation in nAMD eyes with good response to a loading phase of aflibercept. However, its potential role as an independent nAMD activity biomarker is limited as most resolve after the loading phase.

Texture-Based Radiomic SD-OCT Features Associated With Response to Anti-VEGF Therapy in a Phase III Neovascular AMD Clinical Trial

Purpose

The goal of this study was to evaluate the role of texture-based baseline radiomic features (Fr) and dynamic radiomics alterations (delta, FΔr) within multiple targeted compartments on optical coherence tomography (OCT) scans to predict response to anti-vascular endothelial growth factor (VEGF) therapy in neovascular age-related macular degeneration (nAMD).

Methods

HAWK is a phase 3 clinical trial data set of active nAMD patients (N = 1082) comparing brolucizumab and aflibercept. This analysis included patients receiving 6 mg brolucizumab or 2 mg aflibercept and categorized as complete responders (n = 280) and incomplete responders (n = 239) based on whether or not the eyes achieved/maintained fluid resolution on OCT. A total of 481 Fr were extracted from each of the fluid, subretinal hyperreflective material (SHRM), retinal tissue, and sub-retinal pigment epithelium (RPE) compartments. Most discriminating eight baseline features, selected by the minimum redundancy, maximum relevance feature selection, were evaluated using a quadratic discriminant analysis (QDA) classifier on the training set (Str, n = 363) to differentiate between the two patient groups. Classifier performance was subsequently validated on independent test set (St, n = 156).

Results

In total, 519 participants were included in this analysis from the HAWK phase 3 study. There were 280 complete responders and 219 incomplete responders. Compartmental analysis of radiomics featured identified the sub-RPE and SHRM compartments as the most distinguishing between the two response groups. The QDA classifier yielded areas under the curve of 0.78, 0.79, and 0.84, respectively, using Fr, FΔr, and combined Fr, FΔr, and Fc on St.

Conclusions

Utilizing compartmental static and dynamic radiomics features, unique differences were identified between eyes that respond differently to anti-VEGF therapy in a large phase 3 trial that may provide important predictive value.

Translational Relevance

Imaging biomarkers, such as radiomics features identified in this analysis, for predicting treatment response are needed to enhanced precision medicine in the management of nAMD.

Prechoroidal Cleft Regression After Switch to Intravitreal Brolucizumab

INTRODUCTION

Prechoroidal cleft has been described as a negative prognostic biomarker in patients affected with neovascular age related macular degeneration (nAMD). This peculiar finding consists of a lenticular hyporeflective space located between an outward bowing of Bruch's membrane and the base of a fibrovascular retinal pigment epithelium detachment (PED). Previous studies have reported the partial or complete regression of prechoroidal clefts after treatment with anti-vascular endothelial growth factor (VEGF) injections.

CASE REPORT

To report a case of complete anatomical regression of an unresponsive prechoroidal cleft after switching to intravitreal Brolucizumab. The patient maintained cleft regression over time and no adverse events (i.e., RPE tears, intraocular inflammation) were observed during follow-up.

CONCLUSIONS AND IMPORTANCE

To our knowledge, this case report is the first to analyze the clinical efficacy of brolucizumab targeting prechoroidal clefts. Clinical implication and pathogenesis of prechoroidal clefts are yet to be fully elucidated.

Structural and clinical changes in previously treated type 1 macular neovascularization in non-responder AMD eyes switched to brolucizumab

PURPOSE

To examine structural and clinical changes in previously treated type 1 macular neovascularization (MNV) in non-responder age-related macular degeneration (nAMD) eyes switched to brolucizumab. Subretinal hyper-reflective material (SHRM), intraretinal (IRF) and subretinal fluid (SRF) presence, fibrovascular-pigment epithelium detachment (PED) height and central macular thickness (CMT) variation were analyzed using optical coherence tomography (OCT).

METHODS

In this prospective study all patients underwent a complete ophthalmological evaluation including structural OCT at baseline (T0), one month (T1), three (T2), four (T3) and six months after switching to brolucizumab treatment (T4). Non-responder criterion was the persistence of IRF and SRF. Moreover, CMT and BCVA had shown worsening or no improvement before switching to brolucizumab. Clinical function and structural activity biomarkers were measured at each visit and changes were analyzed. P value <0.05 was considered statistically significant.

RESULTS

Twenty eyes of twenty patients were enrolled. All the structural variables examined during the follow-up showed significant reductions. Decreases in IRF, SRF and PED were already significant at T1 (p < 0.05). SHRM was significantly reduced at T2 (p < 0.05). Structural biomarkers were absent at T3. At T4, all biomarkers remained stable while SHRM was no longer detectable in 18 patients. Changes in visual acuity from baseline to T4 were not significant.

CONCLUSION

This short-term experience highlights that brolucizumab might be considered an effective treatment option in nAMD with type 1 MNV, as it can promote a reduction of structural activity biomarkers.

Association between visual impairment and psychosis: A longitudinal study and nested case-control study of adults

BACKGROUND

Theories propose that visual impairment might increase the risk of psychosis, and vice versa. We aimed to investigate the relationship between visual impairment and psychosis in the UK Biobank cohort.

STUDY DESIGN

In a nested case control study of ~116,000 adults, we tested whether a Schizophrenia Spectrum Disorder (SSD) diagnosis as exposure was associated with visual impairment. We also tested longitudinally whether poorer visual acuity, and thinner retinal structures on Optical Coherence Tomography (OCT) scans in 2009 were associated with psychotic experiences in 2016. We adjusted for age, sex, depression and anxiety symptoms; and socioeconomic variables and vascular risk factors where appropriate. We compared complete case with multiple imputation models, designed to reduce bias potentially introduced by missing data.

RESULTS

People with visual impairment had greater odds of SSD than controls in multiply imputed data (Adjusted Odds Ratio [AOR] 1.42, 95 % Confidence Interval [CI] 1.05-1.93, p = 0.021). We also found evidence that poorer visual acuity was associated with psychotic experiences during follow-up (AOR per 0.1 point worse visual acuity score 1.06, 95 % CI 1.01-1.11, p = 0.020; and 1.04, 95 % CI 1.00-1.08, p = 0.037 in right and left eye respectively). In complete case data (15 % of this cohort) we found no clear association, although confidence intervals included the multiple imputation effect estimates. OCT measures were not associated with psychotic experiences.

CONCLUSIONS

Our findings highlight the importance of eye care for people with psychotic illnesses. We could not conclude whether visual impairment is a likely causal risk factor for psychosis.

Characteristics and Classification of Choroidal Caverns in Patients with Various Retinal and Chorioretinal Diseases

PURPOSE

To investigate the features of choroidal caverns in diverse retinal diseases with swept-source optical coherence tomography (SS-OCT).

METHODS

Subjects with normal eyes, retinitis pigmentosa (RP), wet age-related macular degeneration (wAMD), acute central serous chorioretinopathy (CSC), or chronic CSC were enrolled. The characteristics of choroidal caverns were evaluated with SS-OCT. The prevalence of choroidal caverns in retinal diseases and the correlations between the number, width and depth of choroidal caverns with the thickness of choroid were analyzed.

RESULTS

Among 315 eyes of 220 subjects, choroidal caverns were found in 110 eyes (34.9%). Choroidal caverns were divided into two categories based on their location and size. Type I was small and usually lobulated, presented in the choroidal capillary and Sattler's layers. Type II was larger, usually isolated, and presented in the Sattler's and Haller's layers. The prevalence of type I in subjects with normal eyes, RP, wAMD, acute CSC, or chronic CSC was 17.4%, 19.6%, 1.6%, 32.8%, and 85.2%, respectively, while that of type II was 0%, 0%, 21.3%, 13.8%, and 53.7%, respectively. The number, width, and thickness of type II choroidal caverns correlated positively with macular choroidal thickness.

CONCLUSIONS

Choroidal caverns could be divided into two categories. Type II choroidal caverns appeared associated with the pachychoroid spectrum and RPE atrophic diseases.

Findings of uncertain significance by optical coherence tomography (OCT) as prognostic factors in neovascular age-related macular degeneration (nAMD) treated with ranibizumab

Background

Biomarkers hold great promise for personalized medicine as information gained from diagnostic or progression markers can be used to tailor treatment to the individual for highly effective intervention in the disease process.

Methods

The aim of this retrospective study was to evaluate the association between visual outcome and the presence of findings of uncertain significance by optical coherence tomography (OCT) pre and post loading dose in patients with neovascular age-related macular degeneration (nAMD) treated with ranibizumab.

Results

Univariate analysis revealed a higher letter gain in those with presence of onion sign (+ 5.6 ETDRS letters, p = 0.04) absence of prechoroidal cleft (+ 3.7 ETDRS letters, p = 0.04), intraretinal pseudocysts (+4.8 ETDRS letters, p = 0.002), subretinal pseudocysts (+ 4.6 ETDRS letters, p = 0.005) and choroidal caverns (+ 4.4 ETDRS, letters p = 0.0065).

Conclusions

The presence of prechoroidal cleft, intraretinal and subretinal pseudocysts and choroidal caverns were associated with lower visual gains. Moreover, we found that the onion sign is related as a biomarker of good prognostics.

Trial registration Registration number: 2021R13B2. Date of registration: 01/05/2020

OCT applications in contact lens fitting

Optical Coherence Tomography (OCT) is a noninvasive, high-speed, high-resolution imaging technology based in the Michaelson interferometry. A near-infrared light beam is used to register the intensity variations for the light backscattered on each sample layer. Due to the high repeatability on corneal measurements, spectral domain OCT (SD-OCT) is the gold standard when talking about in vivo, non-invasive anterior segment imaging. Changes in the morphology of various ocular surfaces such as the cornea, conjunctiva, limbus or tear film with soft (SCL), rigid, corneal or scleral lens (SL) wear can be described by OCT measurements. For instance, evaluation of the corneoscleral region is essential on SL fitting. For orthokeratology lenses central epithelial thinning and peripheral thickening and their regression could be quantified with OCT after Ortho-K lens wear. Blood vessel compression on the landing zone as well as vault thickness and fluid reservoir (FR) turbidity could be imaged with OCT. Tear film evaluation on contact lens wearers is essential because its use could lead to variations on the biochemical components in tears. Changes in tear meniscus dynamics and several parameters such as volume (TMV), tear meniscus height (HMT) and turbidity could be determined with OCT and positively correlated with the instillation of different ophthalmic solutions with Non-Invasive Break Up Time (NIBUT) and Schirmer test values. This manuscript shows the increasing applicability of OCT technology for the in vivo characterization of contact lens fitting and interaction with the ocular surface in a faster, safer and non-invasive way. Future research will still allow exploring OCT imaging to its full potential in contact lens practice, as there is still a significant amount of information contained in the images that are not yet easy to extract, analyze and give clinical value.

Prechoroidal cleft thickness correlates with disease activity in neovascular age-related macular degeneration

Purpose

The purpose of this study was to investigate the structural variations of the hyporeflective pocket of fluid (prechoroidal cleft) located between Bruch’s membrane and the hyperreflective material within the pigment epithelial detachment (PED) in patients with neovascular age-related macular degeneration (nAMD).

Methods

In this retrospective, observational case series study, patients diagnosed with nAMD and prechoroidal cleft associated with other activity signs of the macular neovascularization (MNV) were included. Structural optical coherence tomography (OCT) scans were evaluated to obtain anatomical measurements of prechoroidal cleft and PED at three different visits (T0, inactive MNV; T1, active MNV; T2, treated inactive MNV). The variations in size of the cleft and the PED were correlated with nAMD activity.

Results

Twenty-nine eyes from 27 patients were included. The subfoveal measurements showed a significant increase of prechoroidal cleft height and width from T0 to T1 (P < 0.05) and a subsequent decrease of the cleft height after treatment with anti-VEGF agents (P = 0.004). A similar significant trend was observed for the greatest prechoroidal cleft height and width, obtained assessing the whole OCT raster. In the multivariate analysis, the cleft height was significantly affected by both time (P = 0.001) and PED height (P < 0.0001). By contrast, the effect of fibrovascular tissue size within the PED was not significant. Visual acuity did not correlate with prechoroidal cleft size.

Conclusion

Prechoroidal cleft increased in association with MNV reactivation and decreased after treatment. Our results suggest that prechoroidal cleft could represent an accumulation of fluid actively exudating from the MNV and should be considered a sign of nAMD activity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05384-w.

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.

Morphological features and prognostic significance of multilayered pigment epithelium detachment in age-related macular degeneration

AIMS

To investigate the structure of multilayered pigment epithelial detachment (m-PED) in neovascular age-related macular degeneration, and its association with visual prognosis and the progression of fibrotic scars at 12 months.

METHODS

We retrospectively analysed 68 eyes of 63 patients with m-PED that included a prechoroidal cleft. The compartments within m-PED were divided into neovascular tissue (layer 1), a hyper-reflective band (layer 2), and a prechoroidal cleft (layer 3). Clinical variables were compared between patients manifesting layer 2 and those who did not. Multiple regression analyses were used to find the factors related to visual outcome and fibrotic scar formation.

RESULTS

Layer 2 was detected in 38 (55.9 %) of 68 eyes. With continuous treatment, the group with layer 2 showed gradual visual deterioration (p<0.001 at month 12), while the group without layer 2 showed visual improvement (p<0.001 at month 12). In the group with layer 2, the thickness of layer 2 significantly increased, and in the group without layer 2, if it formed, it increased gradually (p=0.004 at month 12). In both groups, other layers significantly decreased by month 12. The presence of layer 2 at baseline was significantly associated with a poor visual outcome (p=0.009) and fibrotic scar formation (p=0.023).

CONCLUSIONS

The m-PED with layer 2 had a higher risk of fibrotic scar formation and was associated with a poor visual prognosis. Layer 2 may be an early stage precursor of a fibrotic scar.

Non-invasive multimodal imaging of Diabetic Retinopathy: A survey on treatment methods and Nanotheranostics

Diabetes Retinopathy (DR) is one of the most prominent microvascular complications of diabetes. It is one of the pre-eminent causes for vision impairment followed by blindness among the working-age population worldwide. The de facto cause for DR remains challenging, despite several efforts made to unveil the mechanism underlying the pathology of DR. There is quite less availability of the low cost pre-emptive theranostic imaging tools in terms of in-depth resolution, due to the multiple factors involved in the etiology of DR. This review work comprehensively explores the various reports and research works on all perspectives of diabetic retinopathy (DR), and its mechanism. It also discusses various advanced non-destructive imaging modalities, current, and future treatment approaches. Further, the application of various nanoparticle-based drug delivery strategies used for the treatment of DR are also discussed. In a nutshell, the present review work bolsters the pursuit of the development of an advanced non-invasive optical imaging modal with a nano-theranostic approach for the future diagnosis and treatment of DR and its associated ocular complications.

Toward optical coherence tomography on a chip: in vivo three-dimensional human retinal imaging using photonic integrated circuit-based arrayed waveguide gratings

In this work, we present a significant step toward in vivo ophthalmic optical coherence tomography and angiography on a photonic integrated chip. The diffraction gratings used in spectral-domain optical coherence tomography can be replaced by photonic integrated circuits comprising an arrayed waveguide grating. Two arrayed waveguide grating designs with 256 channels were tested, which enabled the first chip-based optical coherence tomography and angiography in vivo three-dimensional human retinal measurements. Design 1 supports a bandwidth of 22 nm, with which a sensitivity of up to 91 dB (830 µW) and an axial resolution of 10.7 µm was measured. Design 2 supports a bandwidth of 48 nm, with which a sensitivity of 90 dB (480 µW) and an axial resolution of 6.5 µm was measured. The silicon nitride-based integrated optical waveguides were fabricated with a fully CMOS-compatible process, which allows their monolithic co-integration on top of an optoelectronic silicon chip. As a benchmark for chip-based optical coherence tomography, tomograms generated by a commercially available clinical spectral-domain optical coherence tomography system were compared to those acquired with on-chip gratings. The similarities in the tomograms demonstrate the significant clinical potential for further integration of optical coherence tomography on a chip system.

Ganglion Cell Layer Thinning in Alzheimer's Disease

The main advantages of optical retinal imaging may allow researchers to achieve deeper analysis of retinal ganglion cells (GC) in vivo using optical coherence tomography (OCT). Using this device to elucidate the impact of Alzheimer’s disease (AD) on retinal health with the aim to identify a new AD biomarker, a large amount of studies has analyzed GC in different stages of the disease. Our review highlights recent knowledge into measuring retinal morphology in AD making distinctive between whether those studies included patients with clinical dementia stage or also mild cognitive impairment (MCI), which selection criteria were applied to diagnosed patients included, and which device of OCT was employed. Despite several differences, previous works found a significant thinning of GC layer in patients with AD and MCI. In the long term, an important future direction is to achieve a specific ocular biomarker with enough sensitivity to reveal preclinical AD disorder and to monitor progression.