Fundus autofluorescence imaging in posterior uveitis

Fundus Autofluorescence in Posterior and Panuveitis-An Under-Estimated Imaging Technique: A Review and Case Series

Fundus autofluorescence (FAF) is a prompt and non-invasive imaging modality helpful in detecting pathological abnormalities within the retina and the choroid. This narrative review and case series provides an overview on the current application of FAF in posterior and panuveitis. The literature was reviewed for articles on lesion characteristics on FAF of specific posterior and panuveitis entities as well as benefits and limitations of FAF for diagnosing and monitoring disease. FAF characteristics are described for non-infectious and infectious uveitis forms as well as masquerade syndromes. Dependent on the uveitis entity, FAF is of diagnostic value in detecting disease and following the clinical course. Currently available FAF modalities which differ in excitation wavelengths can provide different pathological insights depending on disease entity and activity. Further studies on the comparison of FAF modalities and their individual value for uveitis diagnosis and monitoring are warranted.

Fundus autofluorescence in uveitis: from pathogenesis to imaging interpretation

PURPOSE

This review aims to summarize the current fundus autofluorescence (FAF) ailment for diagnosis and follow-up of uveitis.

METHODS

A thorough literature search was performed in the PubMed database.

RESULTS

FAF maps the retinal pigment epithelium's (RPE) health. Therefore, several posterior infectious and non. This fast, easy-to-perform, noninvasive technique can detect and manage infectious uveitis.

CONCLUSIONS

FAF serves to understand pathophysiologic mechanisms of uveitis and is a valuable prognostic indicator of themselves.

Spectrally resolved autofluorescence imaging in posterior uveitis

Clinical discrimination of posterior uveitis entities remains a challenge. This exploratory, cross-sectional study investigated the green (GEFC) and red emission fluorescent components (REFC) of retinal and choroidal lesions in posterior uveitis to facilitate discrimination of the different entities. Eyes were imaged by color fundus photography, spectrally resolved fundus autofluorescence (Color-FAF) and optical coherence tomography. Retinal/choroidal lesions’ intensities of GEFC (500–560 nm) and REFC (560–700 nm) were determined, and intensity-normalized Color-FAF images were compared for birdshot chorioretinopathy, ocular sarcoidosis, acute posterior multifocal placoid pigment epitheliopathy (APMPPE), and punctate inner choroidopathy (PIC). Multivariable regression analyses were performed to reveal possible confounders. 76 eyes of 45 patients were included with a total of 845 lesions. Mean GEFC/REFC ratios were 0.82 ± 0.10, 0.92 ± 0.11, 0.86 ± 0.10, and 1.09 ± 0.19 for birdshot chorioretinopathy, sarcoidosis, APMPPE, and PIC lesions, respectively, and were significantly different in repeated measures ANOVA (p < 0.0001). Non-pigmented retinal/choroidal lesions, macular neovascularizations, and fundus areas of choroidal thinning featured predominantly GEFC, and pigmented retinal lesions predominantly REFC. Color-FAF imaging revealed involvement of both, short- and long-wavelength emission fluorophores in posterior uveitis. The GEFC/REFC ratio of retinal and choroidal lesions was significantly different between distinct subgroups. Hence, this novel imaging biomarker could aid diagnosis and differentiation of posterior uveitis entities.

Sarcoid Uveitis: An Intriguing Challenger

The purpose of our work is to describe the actual knowledge concerning etiopathogenesis, clinical manifestations, diagnostic procedures, complications and therapy of ocular sarcoidosis (OS). The study is based on a recent literature review and on the experience of our tertiary referral center. Data were retrospectively analyzed from the electronic medical records of 235 patients (461 eyes) suffering from a biopsy-proven ocular sarcoidosis. Middle-aged females presenting bilateral ocular involvement are mainly affected; eye involvement at onset is present in one-third of subjects. Uveitis subtype presentation ranges widely among different studies: panuveitis and multiple chorioretinal granulomas, retinal segmental vasculitis, intermediate uveitis and vitreitis, anterior uveitis with granulomatous mutton-fat keratic precipitates, iris nodules, and synechiae are the main ocular features. The most important complications are cataract, glaucoma, cystoid macular edema (CME), and epiretinal membrane. Therapy is based on the disease localization and the severity of systemic or ocular involvement. Local, intravitreal, or systemic steroids are the mainstay of treatment; refractory or partially responsive disease has to be treated with conventional and biologic immunosuppressants. In conclusion, we summarize the current knowledge and assessment of ophthalmological inflammatory manifestations (mainly uveitis) of OS, which permit an early diagnostic assay and a prompt treatment.

Measuring Inflammation in the Vitreous and Retina: A Narrative Review

Uveitis consists of a group of syndromes characterised by intraocular inflammation, accounting for up to 15% of visual loss in the western world and 10% worldwide. Assessment of intraocular inflammation has been limited to clinician-dependent, subjective grading. Developments in imaging technology, such as optical coherence tomography (OCT), have enabled the development of objective, quantitative measures of inflammatory activity. Important quantitative metrics including central macular thickness and vitreous signal intensity allow longitudinal monitoring of disease activity and can be used in conjunction with other imaging modalities enabling holistic assessment of ocular inflammation. Ongoing work into the validation of instrument-based measures alongside development of core outcome sets is crucial for standardisation of clinical trial endpoints and developing guidance for quantitative multi-modal imaging approaches. This review outlines methods of grading inflammation in the vitreous and retina, with a focus on the use of OCT as an objective measure of disease activity.

Acute posterior multifocal placoid pigment epitheliopathy (APMPPE)

Background

Acute posterior multifocal placoid pigment epitheliopathy (APMPPE) is a rare inflammatory eye disease, affecting the inner choroid and the outer retina. Recent advances in multimodal imaging have been important in the understanding of the pathophysiology of the disease, allowing a better characterization of the morphology of this condition.

Methods

Narrative review.

Results

In this review, a comprehensive overview of clinical features, imaging findings, treatment management, and long-term outcomes of patients with APMPPE will be provided.

Conclusions

Although APMPPE was originally believed to be a self-limited condition with a good prognosis, the disease can be recurrent and result in significant loss of vision function. Fundus imaging plays an important role in the diagnosis and management of the disease, allowing to evaluate response to treatment and onset of complications.

Structural Endpoints and Outcome Measures in Uveitis

Most uveitis entities are rare diseases but, taken together, are responsible for 5-10% of worldwide visual impairment which largely affects persons of working age. As with many rare diseases, there is a lack of high-level evidence regarding its clinical management, partly due to a dearth of reliable and objective quantitative endpoints for clinical trials. This review provides an overview of available structural outcome measures for uveitis disease activity and damage in an anatomical order from the anterior to the posterior segment of the eye. While there is a multitude of available structural outcome measures, not all might qualify as endpoints for clinical uveitis trials, and thorough testing of applicability is warranted. Furthermore, a consensus on endpoint definition, standardization, and "core outcomes" is required. As stipulated by regulatory agencies, endpoints should be precisely defined, clinically important, internally consistent, reliable, responsive to treatment, and relevant for the respective subtype of uveitis. Out of all modalities used for assessment of the reviewed structural outcome measures, optical coherence tomography, color fundus photography, fundus autofluorescence, and fluorescein/indocyanine green angiography represent current "core modalities" for reliable and objective quantification of uveitis outcome measures, based on their practical availability and the evidence provided so far.

Multimodal imaging in infectious and noninfectious intermediate, posterior and panuveitis

PURPOSE OF REVIEW

Given the heterogeneity of uveitis, markers of inflammation vary from patient to patient. Multimodal imaging has proven itself to be critical for accurate evaluation for disease activity and treatment response in uveitis.

RECENT FINDINGS

Ultra-widefield (UWF) fluorescein angiography and autofluorescence (AF) as well as optical coherence tomography angiography (OCTA) have provided insights into disease pathogenesis and monitoring not previously appreciated. In addition to structural retinal imaging, OCT can be used to assess the choroid, the posterior cortical vitreous and the retinal vasculature in eyes with uveitis.

SUMMARY

Multimodal ocular imaging in eyes with uveitis is critical for disease diagnosis and assessing response to treatment. UWF fluorescein angiography can detect retinal vasculitis even in the absence of overt vascular sheathing. UWF AF can help detect more chorioretinal lesions than clinically visible. OCT can be used to assess the posterior cortical vitreous, retina, large retinal vessels and choroid in uveitis. The use of multimodal imaging will likely be needed to determine clinical trial endpoints in studies evaluating therapeutics for uveitis.

Multimodal Imaging in Ocular Sarcoidosis

Aim: Ocular sarcoidosis presents a diagnostic challenge because of its varied clinical presentations. It is important to distinguish sarcoidosis from other uveitis diseases. Multimodal imaging provides useful data to be introduced into clinical practice. Methods: This is a review article. Conclusions: This review article highlights the role of fundus fluorescein angiography (FA), indocyanine green angiography (ICG), optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA) in the diagnosis and management of ocular sarcoidosis. This review article highlights the role of fundus fluorescein angiography (FA), indocyanine green angiography (ICG), optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA) in the diagnosis and management of ocular sarcoidosis.

Multimodal Imaging in Ocular Toxoplasmosis

Multimodal imaging relies on combination of multiple imaging modalities to precisely delineate pathological changes in the posterior segment of the eye associated with a wide range of conditions. This combined application of fundus photography, optical coherence tomography, fundus reflectance/autofluorescence and fundus angiography (with fluorescein, indocyanine green and/or optical coherence tomography) is of great utility for assessment of patients with ocular toxoplasmosis. Multimodal imaging is helpful to characterize the typical pattern of toxoplasmic retinochoroiditis, with primary focal inflammatory involvement of the neurosensory retina, and secondary changes at the level of underlying choroid, retinal blood vessels, vitreous and even optic disc. It may also be valuable to document and follow local complications, including macular edema, vascular occlusions, and choroidal neovascularization, among others.

Multimodal Imaging in Sympathetic Ophthalmia

PURPOSE

To show the current status of multimodal imaging and its role in supporting an early diagnosis of sympathetic ophthalmia.

METHODS

The diagnosis is mainly clinical supported with ancillary investigations; mainly fluorescein angiography and others, including indocyanine angiography optical coherence tomography (OCT), OCT enhanced depth imaging, autofluorescence imaging, and ultrasonography.

RESULTS

Various imaging modalities such as OCT, autofluorescence imaging and angiography are critical in the diagnosis and management of sympathetic ophthalmia. The clinician must make adequate use of such ancillary investigations in the management of the patients.

CONCLUSIONS

Sympathetic ophthalmia is a rare, bilateral inflammation of the uveal tract following penetrating trauma or surgery in one eye. The intraocular inflammation requires a prompt diagnosis so that the treatment can be initiated as early as possible.

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.

Ocular autofluorescence in diabetes mellitus. A review

Diabetes mellitus is a metabolic disease with a considerable impact on healthcare owing to its increased prevalence and high mortality rate. Structural, morphological, and physiological changes in each of the ocular components have been described in detail. Autofluorescence has been described as a good indicator of metabolic activity. The aim of the present review is to provide an overview of ocular endogenous fluorophores in the cornea, the crystalline lens, and the retinal pigment epithelium, the effects of diabetes mellitus and therefore the potential of autofluorescence assessment for screening and monitoring changes in diabetic patients.

Choroidal Vascularity Index (CVI)--A Novel Optical Coherence Tomography Parameter for Monitoring Patients with Panuveitis?

PURPOSE

To compute choroidal vascularity index (CVI) using an image binarization tool on enhanced depth imaging (EDI)-optical coherence tomography (OCT) scans as a non-invasive optical tool to monitor progression in panuveitis and to investigate the utility of volumetric data from EDI-OCT scans using custom image analysis software.

MATERIALS AND METHODS

In this retrospective cohort study, segmented EDI-OCT scans of both eyes in 19 patients with panuveitis were taken at baseline and at 3-month follow-up and were compared with EDI-OCT scans of normal eyes. Subfoveal choroidal area was segmented into luminal (LA) and stromal interstitial area (SA). Choroidal vascularity index (CVI) was defined as the proportion of LA to the total circumscribed subfoveal choroidal area (TCA).

RESULTS

The mean choroidal thickness was 265.5±100.1μm at baseline and 278.4±102.6μm at 3 months follow up (p = 0.06). There was no statistically significant difference in TCA between study and control eyes (p = 0.08). CVI in the control group was 66.9±1.5% at baseline and 66.4±1.5% at follow up. CVI was 74.1±4.7% at baseline and 69.4±4.8% at 3 months follow up for uveitic eyes (p<0.001). The % change in CVI was 6.2 ±3.8 (4.3 to 8.0) for uveitic eyes, which was significantly higher from % change in CVI for control eyes (0.7±1.1, 0.2 to 1.3, p<0.001).

CONCLUSION

The study reports composite OCT-derived parameters and CVI as a possible novel tool in monitoring progression in panuveitis. CVI may be further validated in larger studies as a novel optical tool to quantify choroidal vascular status.

Modeling of in vivo acousto-optic two-photon imaging of the retina in the human eye

Our aim is to establish a novel combined acousto-optical method for in vivo imaging of the human retina with the two-photon microscope. In this paper we present modeling results based on eye model samples constructed with parameters measured on patients. We used effectively the potential of the electronic compensation offered by the acousto-optic lenses to avoid the use of adaptive optical correction. Simulation predicted lateral resolution between 1.6 µm and 3 µm on the retina. This technology allows the visualization of single cells and promises real time measuring of neural activity in individual neurons, neural segments and cell assemblies with 30-100 µs temporal and subcellular spatial resolution.

Role of autofluorescence in inflammatory/infective diseases of the retina and choroid

Fundus autofluorescence (FAF) has recently emerged as a novel noninvasive imaging technique that uses the fluorescent properties of innate fluorophores accumulated in the retinal pigment epithelium (RPE) to assess the health and viability of the RPE/photoreceptor complex. Recent case reports suggest FAF as a promising tool for monitoring eyes with posterior uveitis helping to predict final visual outcome. In this paper we review the published literature on FAF in these disorders, specifically patterns in infectious and noninfectious uveitis, and illustrate some of these with short case histories.