Widespread choroidal thickening and abnormal midperipheral fundus autofluorescence characterize exudative age-related macular degeneration with choroidal vascular hyperpermeability

Choroidal biomarkers in age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of central visual impairment in the elderly. The exact pathophysiological mechanisms for AMD remain uncertain. Several studies suggest that choroidal abnormalities and alterations are critical in AMD progression. The transition from manual to automated segmentation and binarization techniques has resulted in accurate and precise measurements of different choroidal parameters. These qualitative and quantitative parameters, known as choroidal imaging biomarkers, have advanced from basic vertical subfoveal choroidal thickness to more intricate 3-dimensional choroidal reconstruction methods in the last decade. Therefore, a comprehensive evaluation of choroidal metrics may investigate valuable insights into AMD, potentially guiding the future development of customized therapeutic strategies and personalized patient care in AMD management. We describe the role of different choroidal biomarkers in evaluating patients with AMD and their contribution to management.

Quantification of Choroidal Vascular Hyperpermeability on Ultra-Widefield Indocyanine Green Angiography in Macular Neovascularization

To obtain a quantitative parameter for the measurement of choroidal vascular hyperpermeability (CVH) on ultra-widefield indocyanine green angiography (UWICGA) using an objective analysis method in macular choroidal neovascularization (CNV). A total of 113 UWICGA images from 113 subjects were obtained, including with 25 neovascular age-related macular degeneration (nAMD), 37 with polypoidal choroidal vasculopathy (PCV) (19 with thin-choroid and 18 with thick-choroid), 33 with pachychoroid neovasculopathy (PNV), and 18 age-matched controls. CVH was quantified on a gray image by the subtraction of 2 synchronized UWICGA images of early and late phases. The measured CVH parameter was compared with human graders and among CNV subtypes and correlated with choroidal vascular density (CVD) and subfoveal choroidal thickness (SFCT). The mean CVH values were 28.58 ± 4.97, 33.36 ± 8.40, 33.61 ± 11.50, 42.19 ± 13.25, and 43.59 ± 7.86 in controls and patients with nAMD, thin-choroid PCV, thick-choroid PCV, and PNV, respectively (p < 0.001). CVH was higher in thick-choroid PCV and PNV compared to the other groups (all p ≤ 0.006). The measured CVH value positively correlated with those reported by human graders (p < 0.001), CVD, and SFCT (p = 0.001 and p < 0.001, respectively). CVH can be measured objectively using quantitative UWICGA analysis. The CVH parameter differs among macular CNV subtypes and correlates with CVD and SFCT.

Peripheral Manifestations in Age Related Macular Degeneration: A Review of Imaging and Findings

Purpose: To review novel findings in research with ultra-widefield imaging for analysis of peripheral manifestations in macular degeneration (AMD). We introduce the evolving widefield imaging modalities while summarizing the analytical techniques used in data collection of peripheral retinal findings thus far. Our review provides a summary of advancements to date and a commentary on future direction for AMD research. Methods: This is a literature review of all significant publications focused on the relationship between AMD and the retinal periphery conducted within the last two decades. Results and Conclusion: Promising research has been undertaken to elucidate peripheral retinal manifestations in macular degeneration using novel methodology. Advancements in ultra-widefield imaging and fundus autofluorescence have allowed us to elucidate peripheral retinal pigmentary changes, drusen deposition, and much more. Novel grid overlay techniques have been introduced to aid in analyzing these changes for pattern recognition and grouping of findings. This review discusses these findings in detail, providing evidence for the pan-retinal manifestations of AMD. Inter-study discordance in analytical approach highlights a need for more systematic future study.

Evaluation of Peripheral Retinal Changes on Ultra-Widefield Fundus Autofluorescence Images of Patients with Age-Related Macular Degeneration

Objectives:

Age-related macular degeneration (AMD) is the most common cause of central vision loss in individuals aged 65 years and older in developed countries. Earlier imaging systems did not enable visualization of the peripheral retina in diseases affecting the macula. With the introduction of new-generation devices, the peripheral retina is easily visualized. In our study, we aimed to evaluate the incidence of peripheral retinal changes in the color and autofluorescence fundus images of patients with AMD.

Materials and Methods:

In the study group, 550 eyes of 277 patients who were diagnosed with AMD and 90 eyes of 45 healthy patients in the control group were evaluated. An ultra-wide-angle imaging device was used to record standard 200° color and autofluorescence fovea-centered fundus images followed by superior and inferior fundus images obtained using the device’s fixation light. The fundus images were examined in 3 sections: zone 1, zone 2, and zone 3.

Results:

Evaluation of color fundus images revealed peripheral retinal changes in 67.8% of the 550 AMD eyes and 47.8% of the healthy eyes. Drusen was the most common peripheral retinal change. Evaluation of autofluorescence images revealed peripheral autofluorescence changes in 39.6% of the AMD eyes and 28.9% of the healthy eyes. Hypoautofluorescence was the most common autofluorescence change.

Conclusion:

Peripheral retinal changes were more common in AMD patients than the control group, indicating that AMD is not only a macular disease, but can affect the entire retina. Future prospective studies will elucidate the relationship between these peripheral retinal changes and patients’ genetic features and their importance in prognosis, diagnosis, and treatment.

Clinical application of ultra-widefield fundus autofluorescence

PURPOSE

To review the basic principles of ultra-widefield fundus autofluorescence (UWF-FAF) and discuss its clinical application for a variety of retinal and choroidal disorders.

METHODS

A systematic review of the PubMed database was performed using the search terms "ultra-widefield," "autofluorescence," "retinal disease" and "choroidal disease."

RESULTS

UWF-FAF imaging is a recently developed noninvasive retinal imaging modality with a wide imaging range that can locate peripheral fundus lesions that traditional fundus autofluorescence cannot. Multiple commercially available ultra-widefield imaging systems, including Heidelberg Spectralis and Optomap Ultra-Widefield systems, are available to the clinician. Imaging by UWF-FAF is more comprehensive; it can reflect the content and distribution of the predominant ocular fluorophore in retinal pigment epithelial cells and evaluate the metabolic status of RPE of various retinal and choroidal disorders.

CONCLUSION

UWF-FAF can detect abnormalities that traditional fundus autofluorescence cannot; therefore, it can be used to better elucidate disease pathogenesis, analyze genotype-phenotype correlations, diagnose and monitor disease.

Pachychoroid disease: a new perspective on exudative maculopathy

BACKGROUND

Pachychoroid, or the structural and functional abnormalities of the choroid, is one of the most important causes of exudative maculopathies. The purpose of this article is to review the current definitions of pachychoroid and their potential consequences. Most publications are from Asian countries. Although no consensus diagnosis has been reached, pachychoroid is defined by thickened choroid and choroidal vascular hyperpermeability, pachyvessels with inner choroidal attenuation; it is closely linked to pachydrusen. Although some studies suggest choroidal congestion may play a role in its pathogenesis, the exact causes of this condition are still unknown. Pachychoroid is associated with exudative maculopathies including central serous chorioretinopathy, pachychoroid neovasculopathy and polypoidal choroidal vasculopathy (PCV). It is widely accepted that macular neovascular membranes may develop secondary to pachychoroid. Recent clinical observations illustrate the importance of pachychoroid in the etiology of macular neovascularization including neovascular age-related macular degeneration (nAMD).

CONCLUSION

Pachychoroid is an important cause of exudative maculopathies. Both drusen and pachychoroid are increasingly recognized as important causes of macular neovascularization, and eyes formally categorized as typical nAMD or PCV can be further sub-categorized based on the presence or absence of pachychoroid and drusen. There is a need to develop a consensus definition, which will greatly enhance our understanding of pachychoroid and facilitate the development of individual interventions in pachychoroid diseases.

Peripheral Retinal Lesions in Eyes with Age-Related Macular Degeneration Using Ultra-Widefield Imaging: A Systematic Review with Meta-analyses

TOPIC

Age-related macular degeneration (AMD) is highly prevalent among the elderly. We systematically reviewed the literature to provide an overview of ultra-widefield imaging (UWFI) of peripheral retinal lesions in AMD.

CLINICAL RELEVANCE

Information regarding retinal characteristics and prevalence of AMD is based mainly on studies using color photography of the central retina, where early and potentially severe manifestations of the disease are found. However, this approach has the effect of neglecting the periphery. Studies using UWFI provide new evidence to show that clinical features associated with AMD are not exclusive to the area of the macula.

METHODS

Eligible studies had to detect lesions of the peripheral retina (based on the original definition of a standard macular grid, with the addition of 2 zones classed as peripheral) using UWFI in eyes with AMD. Ultra-widefield imaging included pseudocolor photography, fundus autofluorescence, fluorescein angiography, and indocyanine green angiography. Eligibility was restricted to human participants and studies written in English. We searched the bibliographic databases PubMed, the Cochrane Library, EMBASE, and the Web of Science on March 27, 2018. We calculated the prevalence of peripheral findings in eyes with AMD and performed similar meta-analyses on the healthy control group. A random-effects model was used because of possible study heterogeneity.

RESULTS

Twelve studies were eligible for the review, which included 3261 or more eyes. Studies were clinic based, apart from 1 study that was a random population sample of individuals 62 years of age or older. Studies were cross-sectional in nature, apart from 1 case-control study. The peripheral lesions most commonly observed were drusen, atrophy, and changes to the retinal pigment epithelium. In eyes with AMD, peripheral lesions were found in 82.7% of eyes (confidence interval, 78.4%-86.7%) compared with 33.3% of healthy eyes (confidence interval, 28.3%-38.5%).

CONCLUSIONS

Peripheral changes were found to be highly prevalent in eyes with AMD, supporting the claim that the disease is panretinal and not macula only. The clinical significance of peripheral lesions in AMD remains incompletely understood, and therefore, further UWFI studies are recommended.

Ultra-widefield fundus autofluorescence in age-related macular degeneration

Background

Establish accuracy and reproducibility of subjective grading in ultra-widefield fundus autofluorescence (FAF) imaging in patients with age-related macular degeneration (AMD), and determine if an association exists between peripheral FAF abnormalities and AMD.

Methods

This was a prospective, single-blinded case-control study. Patients were consecutively recruited for the study. Patients were excluded if there was a history of prior or active ocular pathology other than AMD or image quality was insufficient for analysis as determined by two independent graders. Control patients were those without any evidence of AMD or other ophthalmic disease apart from cataract. Using the Optos 200Tx (Optos, Marlborough, MA, USA), a ResMax central macula and an ultra-widefield peripheral retina image was taken for each eye in both normal color and short wavelength FAF. Ultra-widefield photographs were modified to mask the macula. Each ResMax and ultra-widefield image was independently graded by two blinded investigators.

Results

There were 28 AMD patients and 11 controls. There was a significant difference in the average age between AMD patients and control groups (80 versus 64, respectively P<0.001). There was moderate, statistically significant agreement between observers regarding image interpretation (78.4%, K = 0.524, P<0.001), and 69.0% (K = 0.49, P<0.001) agreement between graders for FAF abnormality patterns. Patients with AMD were at greater risk for peripheral FAF abnormalities (OR: 3.43, P = 0.019) and patients with FAF abnormalities on central macular ResMax images were at greater risk of peripheral FAF findings (OR: 5.19, P = 0.017).

Conclusion

Subjective interpretation of FAF images has moderate reproducibility and validity in assessment of peripheral FAF abnormalities. Peripheral FAF abnormalities are seen in both AMD and control patients. Those with AMD, poor visual acuity, and macular FAF abnormalities are at greater risk.

Evaluation of peripheral fundus autofluorescence in eyes with wet age-related macular degeneration

PURPOSE

We aimed to evaluate the prevalence of abnormal peripheral fundus autofluorescence (FAF) in wet age-related macular degeneration (AMD) using wide-field imaging instrument.

PATIENTS AND METHODS

A retrospective, case-controlled study involving 66 eyes of 46 Japanese wet AMD patients and 32 eyes of 20 control patients was performed. Wide-field FAF images were obtained for typical AMD (37 eyes/28 patients), polypoidal choroidal vasculopathy (PCV) (22 eyes/20 patients), and retinal angiomatous proliferation (RAP) (seven eyes/four patients). Two masked ophthalmologists independently graded the images for mottled, granular, and nummular patterns. Main outcome measures were abnormal peripheral FAF frequencies and relative risks by disease subgroups and treatments.

RESULTS

Abnormal peripheral FAF patterns were found in 51.5% of wet AMD eyes compared with 18.8% of control eyes (P<0.001). Mottled, granular, and nummular patterns were found in 45.5%, 31.8%, and 16.7%, respectively, of wet AMD eyes. Each disease subgroup (typical AMD, 54.1%; PCV, 36.4%; and RAP, 85.7%) showed significantly higher frequencies of peripheral FAF (P<0.001, P=0.03, and P<0.001, respectively) than control eyes (18.8%). There were no significant differences (P=0.76) between the frequencies in untreated and treated eyes.

CONCLUSION

Eyes of Japanese wet AMD patients had a higher abnormal FAF prevalence compared with control eyes. Among the three disease subtypes, abnormal patterns were least prevalent in PCV eyes.

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.