Fluorescein angiography and spectral-domain optical coherence tomography for monitoring anti-VEGF therapy in myopic choroidal neovascularization

Evaluation of macular neovascularization activity in pathological myopia: a comparison between optical coherence tomography and OCT-angiography

Purpose

The purpose of this study was to suggest a novel approach to assessing the activity of macular neovascularization (MNV) in pathological myopia (PM) by comparing optical coherence tomography (OCT) with OCT-angiography (OCT-A).

Methods

The Zeiss Cirrus HD-5000 was used to obtain OCT and OCT-A images of PM-MNV. The objective was to examine the characteristics of PM-MNV lesions and investigate the relationship between PM-MNV activity and changes in retinal structure in 54 patients (54 eyes). To analyze the OCT parameters associated with PM-MNV activity and their clinical significance in terms of sensitivity and specificity, we used OCT-A as a reference.

Results

This study included 72 patients (72 eyes), of whom 54 had good image quality and were considered for analysis. The study evaluated various OCT characteristics of MNV lesions, including the elevation of an external limiting membrane (ELM), ellipsoidal zone (EZ), retinal pigment epithelium (RPE) elevation, and EZ/RPE interruption, to identify possible parameters associated with PM-MNV activity. The interobserver consistency was found to be almost perfect. In the evaluation of PM-MNV activity, the sensitivity of ELM elevation, EZ interruption, and RPE interruption was found to be 66.7% (low), 88.4% (high), and 95.6% (high), respectively. However, the specificity was found to be 71.4% (moderate), 71.4% (moderate), and 25.4% (poor), respectively. This indicates that the current evaluation methods are not accurately assessing PM-MNV activity. We developed a new comprehensive method that used EZ interruption as the primary parameter and ELM elevation and RPE interruption as secondary parameters to evaluate PM-MNV activity with a sensitivity of 97.8% and a specificity of 85.4%.

Conclusion

In PM-MNV, a novel comprehensive diagnostic method combining EZ interruption, ELM elevation, and RPE interruption might be a valuable indicator to evaluate PM-MNV activity.

Pathologic myopia: advances in imaging and the potential role of artificial intelligence

Pathologic myopia is a severe form of myopia that can lead to permanent visual impairment. The recent global increase in the prevalence of myopia has been projected to lead to a higher incidence of pathologic myopia in the future. Thus, imaging myopic eyes to detect early pathological changes, or predict myopia progression to allow for early intervention, has become a key priority. Recent advances in optical coherence tomography (OCT) have contributed to the new grading system for myopic maculopathy and myopic traction maculopathy, which may improve phenotyping and thus, clinical management. Widefield fundus and OCT imaging has improved the detection of posterior staphyloma. Non-invasive OCT angiography has enabled depth-resolved imaging for myopic choroidal neovascularisation. Artificial intelligence (AI) has shown great performance in detecting pathologic myopia and the identification of myopia-associated complications. These advances in imaging with adjunctive AI analysis may lead to improvements in monitoring disease progression or guiding treatments. In this review, we provide an update on the classification of pathologic myopia, how imaging has improved clinical evaluation and management of myopia-associated complications, and the recent development of AI algorithms to aid the detection and classification of pathologic myopia.

Macular density alterations in myopic choroidal neovascularization and the effect of anti-VEGF on it

AIM

To analyse macular microvascular alterations in myopic choroidal neovascularization (mCNV) and the efficiency of anti-vascular endothelial growth factor (anti-VEGF) therapy for mCNV by optical coherence tomography angiography (OCTA).

METHODS

A total of 123 patients were included in this retrospective study, divided into mCNV group, high myopia (HM) group, and normal group at the Affiliated Eye Hospital of Wenzhou Medical University from January 2017 to January 2019. Superficial vessel density, deep capillary density, foveal avascular zone (FAZ) area, A-circularity index (AI) and vessel density around the 300 µm width of the FAZ region density (FD) and the area of choroidal neovascularization (CNV) lesion (only for mCNV group) were measured on 3×3 mm² OCTA images. FAZ area was corrected for axial length. Central macular thickness (CMT) was measured on OCT in mCNV group. Compared the parameters on OCTA of 3 groups and pre-anti-VEGF and post-anti-VEGF at 1, 2, 3, and 6mo follow-up in mCNV group.

RESULTS

There were significant differences among 3 groups in superficial vessel density, deep capillary density and FD (P<0.05). FAZ area in HM group was smaller than normal group (P<0.05), but there was no significant difference between mCNV group and the other two group. AI increased in mCNV group (P<0.05). The mean CMT, area and flow area of CNV lesion decreased after treatment (P<0.05), while vessel density and FAZ didn't change. The mean CMT, area and flow area of CNV lesion statistically decreased after anti-VEGF treatment in mCNV group (P<0.05), while superficial vessel density, deep capillary density and FAZ area, AI and FD didn't change. The mean reduction ratio of lesions was 50.32% (7.07% to 100%). Lesion regression 100% was observed in 2 cases (4.88%). There was a negative correlation between the CNV lesion area and reduction ratio (r=-0.380, P=0.042) and the flow lesion area and reduction ratio (r=-0.402, P=0.030).

CONCLUSION

Macular vessel density decreases, FAZ turns smaller and more irregular in mCNV eyes. Anti-VEGF therapy is efficient for mCNV without affecting vessel density and FAZ, but it is unable to completely eliminate CNV lesions in most cases. The bigger mCNV lesions have lower reduction ratio.

Structural and optical coherence tomography angiography in myopic choroidal neovascularization: Agreement with conventional fluorescein angiography

PURPOSE

To evaluate the agreement between fluorescein angiography and structural optical coherence tomography in diagnosing and monitoring the activity of myopic choroidal neovascularization and to provide a comparative analysis with optical coherence tomography angiography.

METHODS

Thirteen patients with active myopic choroidal neovascularization were prospectively enrolled. At the baseline, 2-month, and 6-month visits, each patient underwent a complete ophthalmological examination, including best-corrected visual acuity assessment, fundus examination, fluorescein angiography, and optical coherence tomography with structural and angiographic assessment. Sensitivity and specificity for all optical coherence tomography parameters were evaluated taking fluorescein angiography as the reference examination.

RESULTS

At the baseline, fluorescein angiography confirmed myopic choroidal neovascularization leakage in all patients. Structural optical coherence tomography demonstrated intraretinal or subretinal fluid in 61% of cases, fuzzy borders and absence of external limiting membrane visibility in 84% of cases, and subretinal hyperreflective exudation in 53% of cases. Sensitivity to the presence of retinal fluid and subretinal hyperreflective exudation was lower than sensitivity to fuzzy borders and external limiting membrane visibility, which reached 84%. During ranibizumab therapy, external limiting membrane visibility showed a higher sensitivity (100%) compared with fuzzy borders and subretinal hyperreflective exudation (66.6%) while displaying an equal specificity of 100%. At baseline and final visit, sensitivity increased to 100% when all structural optical coherence tomography parameters were pooled. Optical coherence tomography angiography detected myopic choroidal neovascularization at baseline, 2-month, and 6-month visits in 92%, 76%, and 76% of cases, respectively.

CONCLUSION

The study confirms that the new indicators of myopic choroidal neovascularization activity are more reliable than the presence or absence of retinal fluid. Optical coherence tomography angiography identified myopic choroidal neovascularization in most patients in the diagnostic phase and during treatment monitoring and could be considered as an alternative to fluorescein angiography in selected patients.

Fluorescein Leakage and Optical Coherence Tomography Features of Choroidal Neovascularization Secondary to Pathologic Myopia

Purpose

We compare the fluorescein angiography (FA) patterns with morphologic alterations detectable on spectral-domain OCT (SD-OCT) in myopic choroidal neovascularization (mCNV) and evaluate whether they influence the effects of intravitreal ranibizumab (IVRI) in an as-needed (PRN) regimen.

Methods

The 49 patients enrolled in this prospective case series underwent a complete ophthalmologic examination, including best-corrected visual acuity (BCVA), FA, and SD-OCT assessment. The main outcome measure was correlation between FA patterns and SD-OCT features. Secondary outcomes were changes in BCVA and central macular thickness (CMT), and characterization of subretinal hyperreflective exudation (SHE).

Results

Three main patterns were identified on the FA: no (5%), minimal (35%), and profuse (59%) leakage CNV. Comparison between minimal versus profuse leakage CNV subtypes revealed no difference regarding baseline and final BCVA, CNV area, choroidal thickness, final CMT, and proportion of intraretinal cysts, subretinal fluid, and external limiting membrane (ELM) interruption; however, the minimal leakage CNV subgroup revealed a lower percentage of SHE (P = 0.0039), required fewer IVRI (P = 0.003), and showed a baseline smaller CMT (P = 0.004). Patients presenting with SHE showed a similar baseline BCVA to those without exudation, but displayed greater final BCVA improvement. CMT was greater at the baseline and the reduction also was more marked. CNV area achieved a significant reduction only in eyes with SHE. ELM interruption was present in all cases compared to 86.3% of eyes without SHE. Lastly, the eyes with SHE required more injections (P = 0.04).

Conclusions

Different patterns of mCNV may be identified in FA and they correlate with specific SD-OCT alterations. Moreover, the type of FA leakage may assist in identifying more active mCNV.

Imaging in myopia: potential biomarkers, current challenges and future developments

Myopia is rapidly increasing in Asia and around the world, while it is recognised that complications from high myopia may cause significant visual impairment. Thus, imaging the myopic eye is important for the diagnosis of sight-threatening complications, monitoring of disease progression and evaluation of treatments. For example, recent advances in high-resolution imaging using optical coherence tomography may delineate early myopic macula pathology, optical coherence tomography angiography may aid early choroidal neovascularisation detection, while multimodal imaging is important for monitoring treatment response. However, imaging the eye with high myopia accurately has its challenges and limitations, which are important for clinicians to understand in order to choose the best imaging modality and interpret the images accurately. In this review, we present the current imaging modalities available from the anterior to posterior segment of the myopic eye, including the optic nerve. We summarise the clinical indications, image interpretation and future developments that may overcome current technological limitations. We also discuss potential biomarkers for myopic progression or development of complications, including basement membrane defects, and choroidal atrophy or choroidal thickness measurements. Finally, we present future developments in the field of myopia imaging, such as photoacoustic imaging and corneal or scleral biomechanics, which may lead to innovative treatment modalities for myopia.

Computational Approach to Investigating Key GO Terms and KEGG Pathways Associated with CNV

Choroidal neovascularization (CNV) is a severe eye disease that leads to blindness, especially in the elderly population. Various endogenous and exogenous regulatory factors promote its pathogenesis. However, the detailed molecular biological mechanisms of CNV have not been fully revealed. In this study, by using advanced computational tools, a number of key gene ontology (GO) terms and KEGG pathways were selected for CNV. A total of 29 validated genes associated with CNV and 17,639 nonvalidated genes were encoded based on the features derived from the GO terms and KEGG pathways by using the enrichment theory. The widely accepted feature selection method-maximum relevance and minimum redundancy (mRMR)-was applied to analyze and rank the features. An extensive literature review for the top 45 ranking features was conducted to confirm their close associations with CNV. Identifying the molecular biological mechanisms of CNV as described by the GO terms and KEGG pathways may contribute to improving the understanding of the pathogenesis of CNV.

NEOVASCULARIZATION SECONDARY TO HIGH MYOPIA IMAGED BY OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

PURPOSE

To describe the optical coherence tomography angiography (OCTA) characteristics of active myopic choroidal neovascularization (CNV) and to compare its sensitivity versus fluorescein angiography and spectral-domain optical coherence tomography.

METHODS

Consecutive highly myopic patients complicated with active myopic CNV were prospectively included. The OCTA features were analyzed and correlated with the findings of conventional imaging (spectral-domain optical coherence tomography and fluorescein angiography).

RESULTS

Twenty eyes of 19 patients (mean age: 59.6 ± 12.1 years, mean spherical equivalent: -13.5 ± 3.6 diopters) presenting with both treatment-naive CNV and recurrent CNV were included in the analysis. The OCTA showed a 90% sensitivity for myopic CNV detection in 18 of 20 eyes, revealing a high-flow neovascular network accurately visible using a 30-μm manual segmentation underneath Bruch membrane. Mean selected area of myopic CNV on OCTA images was 0.34 ± 0.45 mm, whereas the mean vessel area was 0.22 ± 0.27 mm. Two neovascular phenotypes prevailed in our series: disorganized vascular loops and organized interlacing patterns.

CONCLUSION

The OCTA seems to be a valuable tool in detecting myopic CNV with a high sensitivity. However, its specificity needs to be investigated in further studies.

Anti-Vascular Endothelial Growth Factor Therapy for Myopic Choroidal Neovascularization

Myopic choroidal neovascularization (CNV) is one of the most vision-impairing complications in patients with pathologic myopia. It is also one of the most frequently encountered non.age-related macular degeneration causes of CNV and affects young patients in the working age group. Fluorescein angiography (FA) and spectral domain optical coherence tomography (OCT) are generally indicated to confirm the diagnosis of active myopic CNV before initiation of treatment. Without treatment, natural history studies have shown that the vision outcome can be very poor. More recently, a number of retrospective, prospective and phase 3, multicenter, randomized controlled trials have established the safety and efficacy of intravitreal anti.vascular endothelial growth factor (VEGF) agents for the treatment of myopic CNV. Long-term follow-up studies have found that some of the initial vision gained after intravitreal anti-VEGF therapy may not be maintained, owing to the presence and progression of chorioretinal atrophy (CRA) adjacent to the CNV. Further research on clinical and imaging characteristics may elucidate the prognostic factors that are crucial to optimizing the treatment and prevention of visual impairment associated with myopic CNV.

Treatment of myopic choroidal neovascularization with intravitreal ranibizumab injections: the role of age

PURPOSE

The aim of this study was to explore the role of age as a prognostic factor for the outcome of myopic choroidal neovascularization (CNV) treatment with intravitreal ranibizumab injections.

METHODS

A retrospective review of charts of patients treated with intravitreal injections of ranibizumab for the treatment of myopic CNV was done. Patients with other ophthalmic disease were excluded. Patients were followed for at least 2 years. The correlation between age and the change in visual acuity and the number of injections during treatment was investigated.

RESULTS

Age of the patients was significantly correlated with the number of injections that the patients received (Pearson's r=0.585, P=0.005). Also, it was significantly correlated with improvement in corrected distance visual acuity, defined as the difference between final and initial LogMAR corrected distance visual acuity (Pearson's r=0.614, P=0.003).

CONCLUSION

Age significantly affects the visual outcome of myopic CNV treatment with ranibizumab. Younger patients in our study needed fewer intravitreal injections and achieved a more significant improvement in vision.

Vascular endothelial growth factor inhibitor use and treatment approach for choroidal neovascularization secondary to pathologic myopia

INTRODUCTION

Myopic choroidal neovascularization (CNV) is the most common cause of CNV in those under 50 years of age. It is a significant cause of visual loss in those with pathologic myopia. The current standard of care involves therapy with intravitreal inhibitors of vascular endothelial growth factor (VEGF).

AREAS COVERED

The epidemiology of myopia, high myopia, pathologic myopia, and myopic CNV is reviewed, along with a brief discussion of historical treatments. The pharmacology of the three most commonly used anti-VEGF agents is discussed, with an emphasis on the licensed drugs, ranibizumab and aflibercept. A comprehensive clinical approach to diagnosis and treatment of myopic CNV is presented.

EXPERT OPINION

The current standard of care for myopic CNV is intravitreal inhibition of VEGF, with ranibizumab and aflibercept licensed for intraocular use. The diagnosis, OCT features of disease activity and retreatment algorithm for myopic CNV is different from wet age-related macular degeneration. In the long-term, myopic CNV may be associated with gradual, irreversible visual loss due to progressive chorioretinal atrophy, for which there is currently no treatment.

Long-term outcomes of myopic choroidal neovascularisation treated with combined ranibizumab and dexamethasone characterised by multi-modal imaging

AIM

To characterise the long-term outcomes of myopic choroidal neovascularisation (mCNV) treated with combined ranibizumab and dexamethasone, with the use of multi-modal imaging.

METHODS

A retrospective study of 20 eyes with mCNV treated with intra-vitreal ranibizumab and dexamethasone on a treat-as-needed basis were followed up for a mean period of 47 months (range 19-81 months).

RESULTS

The mean age was 55 ± 16 years, with mean refractive error of -9.0 diopters. Subfoveal mCNV was seen in 11 eyes (52 %) and the others were juxtafoveal. At the final visit, 13 patients (65 %) had improvement, while four patients (20 %) had worsening in vision. The average number of ranibizumab and dexamethasone injections required was 3 ± 1.7. There was a significant improvement in the mean visual acuity, reduction of the central retinal thickness, and an enlargement of the area of chorioretinal atrophy. The mean rate of increase in chorioretinal atrophy area was 0.05 ± 0.09 mm²/month. Disruption of the photoreceptor layer, fragmentation of the retinal pigment epithelium, and breaks in the Bruch's membrane with a hyper-reflective lesion causing separation of the outer retinal layers were changes associated with active mCNV seen on optical coherence tomography (OCT).

CONCLUSION

Visual outcomes of mCNV treated with ranibizumab and dexamethasone on a treat-as-needed basis have favourable visual acuity outcomes. Using multi-modal imaging to monitor treatment response, chorioretinal atrophy, which may be related to visual function, should be used as an additional outcome measure to study the effect of combination treatment versus monotherapy.

Choroidal neovascularization secondary to pathological myopia

Myopic choroidal neovascularization (mCNV), one of the complications of pathological myopia, is also one of the leading causes of visual impairment worldwide. The socioeconomic impact of mCNV in Asian countries is particularly significant due to the rising incidence of pathological myopia. There have been major advances in the treatment of mCNV in the past few years. Previous treatment modalities, such as thermal laser photocoagulation and photodynamic therapy, aimed to prevent vision loss; however, newer modalities such as intravitreal anti-vascular endothelial growth factor (VEGF) agents have been shown to successfully restore vision in many patients. Challenges remain as long term safety and efficacy of anti-VEGF agents are unknown. This article aims to provide a review of the literature of the epidemiology, progression, clinical course and treatment modalities as well as areas of future developments related to myopic CNV.