Significance of the hyperautofluorescent ring associated with choroidal neovascularisation in eyes undergoing anti-VEGF therapy for wet age-related macular degeneration

Macular neovascularization

Neovascularization of the macula, a common complication of many chorioretinal diseases such as neovascular age-related macular degeneration, polypoidal choroidal vasculopathy, and pathologic myopia results from increased synthesis of vascular endothelial growth factor (VEGF) by the retinal pigment epithelium and/or Müller cells because of localized ischemia and inflammation. The Consensus on Neovascular AMD Nomenclature (CONAN) study group acknowledged that these vessels may originate from either the choriocapillaris or the retinal microvasculature, prompting them to propose the term 'macular neovascularization' (MNV) to include intraretinal, subretinal, and sub-pigment epithelial neovascularization localized to the macula. MNV frequently appears as a grey-green macular lesion with overlying intraretinal thickening and/or subretinal exudation, causing metamorphopsia, reduced central vision, relative central scotoma, decreased reading speed, and problems with color recognition. Multimodal imaging with optical coherence tomography (OCT), OCT angiography, dye-based angiographies, fundus autofluorescence, and multiwavelength photography help establish the diagnosis and aid in selecting an appropriate treatment. The standard of care for MNV is usually intravitreal anti-VEGF injections, though thermal laser photocoagulation, verteporfin photodynamic therapy, and vitreoretinal surgery are occasionally used. This current review discusses the etiology and clinical features of MNV, the role of multimodal imaging in establishing the diagnosis, and the available therapeutic options.

Fundus Autofluorescence and Clinical Applications

Fundus autofluorescence (FAF) has allowed in vivo mapping of retinal metabolic derangements and structural changes not possible with conventional color imaging. Incident light is absorbed by molecules in the fundus, which are excited and in turn emit photons of specific wavelengths that are captured and processed by a sensor to create a metabolic map of the fundus. Studies on the growing number of FAF platforms has shown each may be suited to certain clinical scenarios. Scanning laser ophthalmoscopes, fundus cameras, and modifications of these each have benefits and drawbacks that must be considered before and after imaging to properly interpret the images. Emerging clinical evidence has demonstrated the usefulness of FAF in diagnosis and management of an increasing number of chorioretinal conditions, such as age-related macular degeneration, central serous chorioretinopathy, retinal drug toxicities, and inherited retinal degenerations such as retinitis pigmentosa and Stargardt disease. This article reviews commercial imaging platforms, imaging techniques, and clinical applications of FAF.

Imaging Biomarkers and Their Impact on Therapeutic Decision-Making in the Management of Neovascular Age-Related Macular Degeneration

These recommendations, produced by a group of Canadian retina experts, have been developed to assist both retina specialists and general ophthalmologists in the management of vision-threatening neovascular age-related macular degeneration (nAMD). The recommendations are based on published evidence as well as collective experience and expertise in routine clinical practice. We provide an update on practice principles for optimal patient care, focusing on identified imaging biomarkers, in particular retinal fluid, as well as current and emerging therapeutic approaches. Algorithms for delivering high-quality care and improving long-term patient outcomes are provided, with an emphasis on timely and appropriate treatment to preserve and maintain vision. In the context of nAMD, increasing macular fluid or leakage on fluorescein angiography (FA) may indicate disease activity regardless of its location. Early elimination of intraretinal fluid (IRF) is of particular relevance as it is a prognostic indicator of worse visual outcomes. Robust referral pathways for second opinion and peer-to-peer consultations must be in place for cases not responding to intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy.

Retinal Pigment Epithelial Detachment in Age-Related Macular Degeneration

Retinal pigment epithelial detachment is defined as a separation of the retinal pigment epithelium from the inner collagenous layer of Bruch’s membrane. It is a common manifestation in both dry and wet types of age-related macular degeneration. This review aims to provide a comprehensive guide to the pathophysiology, clinical and imaging characteristics, natural course and treatment of the various types of pigment epithelial detachments in order to assist in diagnosis and management of this important feature of age-related macular degeneration.

REGRESSION OF TYPE 2 NEOVASCULARIZATION INTO A TYPE 1 PATTERN AFTER INTRAVITREAL ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

PURPOSE

To study eyes with Type 2 (subretinal) neovascularization (NV) secondary to neovascular age-related macular degeneration (nAMD) that shows lesion regression into a Type 1 (subretinal pigment epithelium) pattern after treatment with intravitreal anti-vascular endothelial growth factor (VEGF) therapy.

METHODS

Retrospective consecutive case series. Patients showing regression of Type 2 neovascularization into a Type 1 pattern after envelopment by retinal pigment epithelium were included in this analysis. A review of the clinical records and multimodal imaging of these cases was performed at baseline, 1, 3, 6, and 12 months. Demographic data, best-corrected visual acuity (BCVA), color fundus photography, fundus autofluorescence (FAF), fluorescein angiography, near-infrared reflectance (NIR), and structural spectral-domain optical coherence tomography (SD-OCT) were reviewed and analyzed. When available, optical coherence tomography angiography images were analyzed as well.

RESULTS

Ten eyes of 9 patients (6 males) diagnosed with treatment-naive pure Type 2 neovascularization secondary to nAMD were included. The mean age was 80.7 years (SD ± 4.30). Mean best-corrected visual acuity expressed in logMAR (Snellen) was 0.45 ± 0.20 (20/55) at baseline and significantly improved to 0.22 ± 0.13 (20/32) at 3-month follow-up (P-value: 0.007). At baseline, color photographs and fundus autofluorescence showed a pigment ring around the neovascular lesion in 6 eyes. A hyperreflective ring was visible on NIR in all eyes at 3-month follow-up. Color photographs showed a tessellated fundus appearance in 9 of the 10 eyes. Serial structural spectral-domain optical coherence tomography scans showed the gradual regression of the Type 2 lesions into a Type 1 pattern with envelopment by the retinal pigment epithelium. En face and cross-sectional optical coherence tomography angiography showed baseline subretinal flow patterns which, after treatment, exhibited reduced flow beneath an intact hyperreflective retinal pigment epithelium (RPE) band.

CONCLUSION

Pure Type 2 lesions are infrequent in nAMD, often leading to poor visual outcomes related to subretinal fibrosis. We describe an alternate regression pattern occurring in eyes with early Type 2 lesions treated with intravitreal anti-vascular endothelial growth factor therapy in which the neovascular tissue is enveloped by retinal pigment epithelium producing a Type 1 pattern. These eyes appear to have better visual outcomes than typically seen with Type 2 lesions related to reduced outer retinal damage.

Confocal scanning laser ophthalmoscopy versus modified conventional fundus camera for fundus autofluorescence

INTRODUCTION

Fundus autofluorescence (FAF) is a noninvasive imaging method to detect fundus endogenous fluorophores, mainly lipofuscin located in the retinal pigment epithelium (RPE). The FAF provides information about lipofuscin distribution and RPE health, and consequently an increased accumulation of lipofuscin has been correlated with ageing and development of certain retinal conditions. Areas covered: An exhaustive literature search in MEDLINE (via OVID) and PUBMED for articles related to ocular FAF in retinal diseases and different devices used for acquiring FAF imaging was conducted. Expert commentary: This review aims to show an overview about autofluorescence in the RPE and the main devices used for acquiring these FAF images. The knowledge of differences in the optical principles, acquisition images and the image post-processing between confocal scanning laser ophthalmoscopy and modified conventional fundus camera will improve the FAF images interpretation when are used as a complementary diagnosis and monitoring tool of retinal diseases.

Clinical applications of fundus autofluorescence in retinal disease

Fundus autofluorescence (FAF) is a non-invasive retinal imaging modality used in clinical practice to provide a density map of lipofuscin, the predominant ocular fluorophore, in the retinal pigment epithelium. Multiple commercially available imaging systems, including the fundus camera, the confocal scanning laser ophthalmoscope, and the ultra-widefield imaging device, are available to the clinician. Each offers unique advantages for evaluating various retinal diseases. The clinical applications of FAF continue to expand. It is now an essential tool for evaluating age related macular degeneration, macular dystrophies, retinitis pigmentosa, white dot syndromes, retinal drug toxicities, and various other retinal disorders. FAF may detect abnormalities beyond those detected on funduscopic exam, fluorescein angiography, or optical coherence tomography, and can be used to elucidate disease pathogenesis, form genotype-phenotype correlations, diagnose and monitor disease, and evaluate novel therapies. Given its ease of use, non-invasive nature, and value in characterizing retinal disease, FAF enjoys increasing clinical relevance. This review summarizes common ocular fluorophores, imaging modalities, and FAF findings for a wide spectrum of retinal disorders.