QUANTITATIVE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY PARAMETER VARIATIONS AFTER TREATMENT OF MACULAR NEOVASCULARIZATION SECONDARY TO AGE-RELATED MACULAR DEGENERATION

Quantitative Optical Coherence Tomography Detection of New Neovascular Branches and Association With Exudation Recurrence in Neovascular Age-Related Macular Degeneration

Purpose

The purpose of this study was to investigate the clinical role of multi-signal quantitative optical coherence tomography angiography (OCTA) perfusion sampling in neovascular age-related macular degeneration (AMD).

Methods

The study was designed as a cross-sectional case series. We collected data from already treated macular neovascularization (MNV), characterized by (I) clinically relevant recurrent exudation, (II) nonclinically relevant recurrent exudation, and (III) inactive lesion. We proposed a new OCTA metric, calculating the gap between high-resolution (HR) and high-speed (HS) OCTA samplings, hypothesizing that this gap might improve the detection of new secondary MNV branches, being also associated with exudation recurrence. Main outcome measures were the HR-HS gap-based categorization of MNV lesions and the assessment of its association with exudative, minimally exudative, and inactive lesions.

Results

Our cohort (which consisted of 32 MNV eyes; 32 patients; mean disease duration 5 years) was classified as type 1 (17; 53%), type 2 (11; 34%), or mixed type (4; 13%) MNV. Subretinal fibrosis was found in 17 out of 32 eyes (53%), whereas outer retinal atrophy involved 22 of 32 eyes (69%). HR-HS MNV gap was significantly different among MNV subgroups: 18% for the exudative subgroup, 12% for the minimally exudative subgroup, and 4% for the inactive subgroup. HR-HS gap significantly correlated with best corrected visual acuity (BCVA), disease duration, fibrosis, and outer retinal atrophy.

Conclusions

HR-HS gap is a novel quantitative metric to detect the secondary novel branches of AMD-related MNV. This parameter is clinically relevant because it is associated with fluid recurrence. The integration of HR-HS gap in artificial intelligence models might help to predict MNV reactivation and to optimize treatment strategies.

Comparative quantitative analysis of optical coherence tomography angiography in varied morphologies of macular neovascularization following intravitreal conbercept and ranibizumab treatments for neovascular age‑related macular degeneration

The present study aimed to examine the optical coherence tomography angiography (OCTA) parameters associated with macular neovascularization (MNV) in patients diagnosed with neovascular age-related macular degeneration (nAMD) and treated with either intravitreal conbercept (IVC) or ranibizumab (IVR). It enrolled 39 nAMD patients presenting with MNV, including 23 in the IVC group and 16 in the IVR group. All participants were treatment-naïve with intravitreal therapy and they underwent treatment following a '3+PRN' regimen. The MNV patterns identified through OCTA were categorized as Medusa, tangled, seafan and other variations. Key outcome measures encompassed best-corrected visual acuity (BCVA), MNV vascular area (MNV-VA), MNV vascular density (MNV-VD) ratio and central macular thickness (CMT). In the present study, 44 eyes were included, with 28 eyes undergoing treatment with IVC and 18 eyes with IVR. On day 90, there was a statistically significant improvement in mean BCVA from baseline among all patients treated with IVC (P=0.002). Notably, improved outcomes were observed in those with the 'tangled' pattern compared with the other three patterns (P=0.007). CMT exhibited a significant decrease from baseline (P=0.007), with consistent improvement observed across all four patterns (P=0.052) on day 90. The mean MNV-VA decreased in all patients, reaching statistical significance for the Medusa pattern (P=0.008), although the improvement in visual acuity was deemed unsatisfactory. Patients with the seafan pattern treated with IVR improved significantly in BCVA (P=0.042). The mean CMT significantly improved from baseline (P=0.001), consistent across the four patterns (P=0.114). Significant improvements were noted in the mean MNV-VA for the seafan pattern and in the mean MNV-VD ratio for the other patterns. The two regimens had no significant differences regarding BCVA, CMT, and MNV parameters. Conbercept emerged as a viable treatment option for patients presenting with tangled MNV patterns. On the other hand, ranibizumab might be considered an effective intervention for individuals with seafan MNV patterns. Notably, the Medusa MNV pattern was associated with a morphologic configuration indicative of a poor prognosis.

Clinical and Imaging Biomarkers Associated with Outer Retinal Atrophy Onset in Exudative Age-Related Macular Degeneration: A Real-Word Prospective Study

INTRODUCTION

Macular neovascularization (MNV) secondary to age-related macular degeneration (AMD) is well managed by anti-vascular endothelial growth factor (anti-VEGF) intravitreal injections. However, outer retinal atrophy represents an unavoidable occurrence detected during follow-up. Several imaging metrics have been proposed as clinically relevant in stratifying the risk of onset of outer retinal atrophy. The main goal of this study is to evaluate the impact of noninvasive imaging metrics on the assessment of outer retinal atrophy onset in a large cohort of eyes with neovascular AMD managed in a real-world setting.

METHODS

This study was a prospective, observational, case series. We included patients affected by newly diagnosed neovascular AMD, requiring anti-VEGF intravitreal injections. We collected clinical and imaging data, with a planned follow-up of 24 months. The multimodal imaging protocol included optical coherence tomography, optical coherence tomography angiography, and fundus autofluorescence. We collected noninvasive imaging metrics and we assessed the relationship with the morphological and functional outcome evaluated at 12-month and 24-month time points.

RESULTS

We included 370 eyes of 370 patients with exudative AMD (210 male; mean age 79 ± 8 years). MNV were classified as follows: type 1, 198 (54%); type 2, 89 (24%); polypoidal choroidal vasculopathy, 29 (7%); and type 3, 54 (15%). A total of 120 out of 370 eyes (33%) showed complete outer retinal atrophy at the end of the 2-year follow-up. The presence of intraretinal fluid, thinning of the Sattler choroidal layer, late anti-VEGF switch, the overall number of anti-VEGF injections, and the perfusion characteristics of the MNV were found to be the most relevant factors associated with the onset of outer retinal atrophy. The other collected metrics were found to be less clinically relevant, also showing no cumulative effect in the multivariate analysis (p > 0.05).

CONCLUSIONS

We identified imaging metrics significantly associated with the 2-year risk onset of outer retinal atrophy. These metrics might pave the way for the development of future customized anti-VEGF treatment strategies.

Quantitative approaches in multimodal fundus imaging: State of the art and future perspectives

When it first appeared, multimodal fundus imaging revolutionized the diagnostic workup and provided extremely useful new insights into the pathogenesis of fundus diseases. The recent addition of quantitative approaches has further expanded the amount of information that can be obtained. In spite of the growing interest in advanced quantitative metrics, the scientific community has not reached a stable consensus on repeatable, standardized quantitative techniques to process and analyze the images. Furthermore, imaging artifacts may considerably affect the processing and interpretation of quantitative data, potentially affecting their reliability. The aim of this survey is to provide a comprehensive summary of the main multimodal imaging techniques, covering their limitations as well as their strengths. We also offer a thorough analysis of current quantitative imaging metrics, looking into their technical features, limitations, and interpretation. In addition, we describe the main imaging artifacts and their potential impact on imaging quality and reliability. The prospect of increasing reliance on artificial intelligence-based analyses suggests there is a need to develop more sophisticated quantitative metrics and to improve imaging technologies, incorporating clear, standardized, post-processing procedures. These measures are becoming urgent if these analyses are to cross the threshold from a research context to real-life clinical practice.

Morphological and Functional Relationship Between OCTA and FA/ICGA Quantitative Features in AMD-Related Macular Neovascularization

Background: The aim was to study the relationship between quantitative information provided by optical coherence tomography (OCT) angiography (OCTA) and conventional angiography in macular neovascularization (MNV) secondary to age-related macular degeneration (AMD).

Methods: The research was designed as an interventional, prospective study. We included 66 eyes (66 patients) affected by naïve MNV. Multimodal imaging included structural OCT, OCTA, fluorescein angiography (FA), and indocyanine green angiography (ICGA). The follow-up lasted 1 year. Patients were treated by PRN anti-VEGF injections. Based on FA/ICGA examinations, we divided the patients into two categories: low vessel tortuosity (VT) (<8.40) and high VT (>8.40), correlating VT with the MNV area, leakage area, speckled fluorescence (SF) quadrants and MNV area/leakage area ratio.

Results: Mean baseline BCVA was 0.50 ± 0.61 LogMAR, improved to 0.31 ± 0.29 LogMAR after 1 year (p < 0.01), with a mean number of 7 ± 2 anti-VEGF injections. The patients revealed type-1 MNV in 36 eyes (55%), mixed type 1 and 2 MNV in 18 eyes (27%), and type-2 MNV in 12 eyes (18%). MNV eyes in high-VT MNV featured poorer BCVA, CMT, and OCTA parameters, higher SF quadrants, and less exudation, compared with low-VT MNV (p < 0.01). Moreover, 30% of high-VT MNV eyes developed outer retinal atrophy.

Conclusions: Low VT MNV turned out to be more exudative at the baseline but less damaging to the outer retinal structures, whereas high VT MNV proved to be less exudative but more prone to lead to atrophic changes and visual function deterioration. VT may be usefully applied to artificial intelligence-based models designed to characterize MNV secondary to AMD.

Microvasculature Features of Vogt-Koyanagi-Harada Disease Revealed by Widefield Swept-Source Optical Coherence Tomography Angiography

Background: Vogt-Koyanagi-Harada (VKH) disease is a multisystem autoimmune disorder which could induce bilateral panuveitis involving the posterior pole and peripheral fundus. Optical coherence tomography angiography (OCTA) provides several advantages over traditional fluorescence angiography for revealing pathological abnormalities of the retinal vasculature. Until recently, however, the OCTA field of view (FOV) was limited to 6 × 6 mm² scans.

Purpose: This study examined retinal vasculature and choriocapillaris abnormalities across multiple regions of the retina (15 × 9 mm² wide field, macular, peripapillary regions) among acute and convalescent VKH patients using a novel widefield swept-source OCTA (WSS-OCTA) device and assessed correlations between imaging features and best-corrected visual acuity (BCVA).

Methods: Twenty eyes of 13 VHK disease patients in the acute phase, 30 eyes of 17 patients in the convalescent phase, and 30 eyes of 15 healthy controls (HCs) were included in this study. Vascular length density (VLD) in superficial and deep vascular plexuses (SVP, DVP), vascular perfusion density (VPD) in SVP, DVP, and choriocapillaris (CC), and flow voids (FV) in CC were measured across multiple retinal regions via WSS-OCTA (PLEX Elite 9000, Carl Zeiss Meditec Inc., USA) using the 15 × 9 mm² scan pattern centered on the fovea and quantified by ImageJ.

Results: Compared to HCs, acute phase VKH patients exhibited significantly reduced SVP-VLD, SVP-VPD, and CC-VPD across multiple retinal regions (all p < 0.01). Notably, the FV area was more extensive in VKH patients, especially those in the acute phase (p < 0.01). These changes were reversed in the convalescent phase. Stepwise multiple linear regression analysis demonstrated that macular DVP-VLD and macular CC-VPD were the best predictive factors for BCVA in the acute and convalescent VKH groups.

Conclusion: The wider field of SS-OCAT provides more comprehensive and detailed images of the microvasculature abnormalities characterizing VKH disease. The quantifiable and layer-specific information from OCTA allows for the identification of sensitive and specific imaging markers for prognosis and treatment guidance, highlighting WSS-OCTA as a promising modality for the clinical management of VKH disease.