AUTOFLUORESCENCE IN ADULT-ONSET FOVEOMACULAR VITELLIFORM DYSTROPHY

PRPH2-ASSOCIATED RETINAL DISEASES: A SYSTEMATIC REVIEW OF PHENOTYPIC FINDINGS

PURPOSE

PRPH2-associated retinal diseases (PARD) result from pathogenic PRPH2 variants, primarily affecting photoreceptor outer segments and retinal pigment epithelium. The focus of this article is to review and discuss the phenotyping of PARD subtypes.

DESIGN

A systematic review.

METHODS

The review followed PRISMA 2020 guidelines with searches on PubMed, Medline, Web of Science, Google Scholar, and Cochrane Library. Eligible studies were those which discussed molecularly confirmed PARD or described associated diseases such as butterfly pattern dystrophy.

INCLUSION

cross-sectional, cohort, case-control studies, book chapters.

EXCLUSION

non-English, conference papers, non-peer-reviewed, or non-full text articles.

RESULTS

PARD is responsible for 25% of pattern dystrophy and up to 5% of inherited retinal dystrophies. There is clear evidence of phenotypic variability between individuals carrying the same pathogenic variant. Fundus autofluorescence, fluorescein angiography, optical coherence tomography, while in research adaptive optics reveal detailed phenotypic characteristics, notably in retinal pigment epithelium changes and photoreceptor disruption. The phenotypic of PARD variability presents diagnostic challenges, with phenotypic features often overlapping with other retinal diseases including age-related macular degeneration, Stargardt disease, and retinitis pigmentosa.

CONCLUSIONS

This review emphasizes revising diagnostic criteria by incorporating more recent imaging techniques and confirming diagnosis with the use of genetic testing. Understanding phenotypic diversity and intrafamilial variability in PARD is crucial for developing new treatments and for patient prognosis and future research should focus on larger cohorts studying genotype-phenotype correlations.

Retinal sensitivity and fundus autofluorescence in adult-onset foveomacular vitelliform dystrophy

The present study aimed to compare retinal sensitivity (RS) at each stage and to evaluate the relationship between RS and fundus autofluorescence (FAF) pattern in adult-onset foveomacular vitelliform dystrophy (AOFVD). We retrospectively reviewed 17 eyes of 13 patients with AOFVD. In addition to best-corrected visual acuity (VA), RS within the affected lesion and optical coherence tomography (OCT) measurements were carried out in each participant. All the examined eyes were classified into 4 stages and 3 FAF patterns. RS was superimposed on OCT fundus image and RS within the affected lesion was calculated in each eye. The relationships between visual functions (VA and RS within the affected lesion) and stages and also FAF patterns were analyzed using the linear mixed model. As a result, RS within the affected lesion was significantly associated with FAF pattern, but not with stage. In contrast, VA was correlated with neither stages nor FAF patterns. Our current result suggested that RS within the affected lesion was related to FAF patterns but this was not the case with VA in eyes with AOFVD, demonstrating the usefulness of measuring RS, not only VA, to comprehend the disease status in AOFVD.

Vitelliform maculopathy: Diverse etiologies originating from one common pathway

Vitelliform lesions (VLs) are associated with a wide array of macular disorders but are the result of one common pathway: retinal pigment epithelium (RPE) impairment and phagocytic dysfunction. VLs are defined by the accumulation of yellowish subretinal material. In the era of multimodal advanced retinal imaging, VLs can be further characterized by subretinal hyperreflectivity with optical coherence tomography and hyperautofluorescence with fundus autofluorescence. VLs can be the result of genetic or acquired retinal diseases. In younger patients, VLs usually occur in the setting of Best disease. Additional genetic causes of VL include pattern dystrophy or adult-onset vitelliform macular dystrophy. In older patients, acquired VLs can be associated with a broad spectrum of etiologies, including tractional, paraneoplastic, toxic, and degenerative disorders. The main cause of visual morbidity in eyes with VLs is the onset of macular atrophy and macular neovascularization. Histopathological studies have provided new insights into the location, nature, and lifecycle of the vitelliform material comprised of melanosomes, lipofuscin, melanolipofuscin, and outer segment debris located between the RPE and photoreceptor layer. Impaired phagocytosis by the RPE cells is the unifying pathway leading to VL development. We discuss and summarize the nature, pathogenesis, multimodal imaging characteristics, etiologies, and natural course of vitelliform maculopathies.

Incidence and risk factors for macular atrophy in Acquired Vitelliform Lesions

PURPOSE

To study the time course to macular atrophy (MA) and associated risk factors in eyes with Acquired Vitelliform Lesions (AVL) as they vary between patients and between eyes of an individual.

DESIGN

Single centre, retrospective, observational cohort study.

SUBJECTS

Consecutive patients registered between Jan 2009 to Jan 2014 with first diagnosis of AVL confirmed by multimodal imaging were included. Eyes with baseline MA or choroidal neovascularization were excluded.

METHODS

Patient demographics were collected. Serial optical coherence tomography (OCT) scans and fundus autofluorescence (FAF) were graded and analysed. Turnbull's estimator was employed, and time censored at 5 years. Multivariable Weibull parametric proportional hazards models was used to assess association of risk factors with MA, following adjustment for age and gender. Hazard ratios are reported with 95% CI.

MAIN OUTCOME MEASURE

Time to the first OCT evidence of MA stratified by presenting visual acuity (VA) and AVL lesion subtypes. Secondary outcome included risk factors for incident MA.

RESULTS

A total of 237 eyes (132 patients) met the inclusion criteria. Incident MA was detected in 52/237 (21.9%) eyes by 5 years. Stratified by baseline VA, 40.3%eyes with VA≤ 70 letters developed atrophy within 5 years of first diagnosis in contrast to 10.3% eyes with VA>70 letters (p<0.001). Based on lesion type only 12.9% eyes with vitelliform lesion at baseline developed MA versus 39.8% and 44.2% eyes with pseudohypopyon or vitelliruptive lesion type respectively. In adjusted analysis, baseline factors associated with increased risk of MA included VA≤70 letters (HR 5.54; 95% CI 2.30-13.34), base width (HR 1.22; 95% CI 1.16-1.28), maximum height (HR 2.61; 95% CI 1.82-3.74), presence of SDD (HR 2.83; 95% CI 1.34 -5.96) and disrupted external limiting membrane (HR 2.81; 95% CI 1.34-5.86).

CONCLUSION

Baseline VA of 70 letters or less (Snellen ≤20/40) and pseudohypopyon or vitelliruptive lesion type attribute highest risk for MA. Other prognostic indicators for MA include baseline presence of SDD, disrupted ELM and larger lesion area.

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.

Assessment of retinal vessel density in adult-onset foveomacular vitelliform dystrophy by optical coherence tomography angiography

BACKGROUND

To evaluate retinal thickness, area of foveal avascular zone (FAZ), flow area and flow density of choriocapillaris, vessel density of both superficial capillary plexus (SCP) and deep capillary plexus (DCP) of eyes with adult-onset foveomacular vitelliform dystrophy (AOFVD) using optical coherence tomography angiography (OCT-A) and compare the results with healthy controls.

METHODS

17 eyes of 14 patients diagnosed with AOFVD and 17 eyes of 17 healthy subjects were enrolled in this study. All patients underwent a complete ophthalmological examination and a 6 x 6 mm macular OCT-A scanning. Quantiative results of retinal thickness, retinal vessel density of SCP and DCP, FAZ area, flow area and flow density of choriocapillaris were analyzed.

RESULTS

No statistically significant differences were noted in the vessel density of the SCP, except for the parafoveal nasal sector (P = 0.048). Similarly, no statistically significant differences were observed in the vessel density of the DCP, except for the parafoveal (P = 0.037) and the parafoveal temporal (P = 0.048) sectors. The choriocapillaris flow area and the flow density were significantly lower in the patients with AOFVD than in the healthy controls (P = 0.001 for both). The mean FAZ area and the retinal thickness measurements were comparable in both groups.

CONCLUSIONS

Patients with AOFVD show vascular abnormalities that can be detected with OCT-A. OCT-A, as a noninvasive imaging modality, could provide a new perspective for understanding the pathophysiology of AOFVD and could also be useful in the follow-up of these patients and in the management of the disease progression.

Investigating the role of BEST1 and PRPH2 variants in the molecular aetiology of adult-onset vitelliform macular dystrophies

Objective: To determine the clinical relevance and frequency of BEST1 and PRPH2 mutations in a clinically diagnosed adult-onset vitelliform macular dystrophy (AVMD) group with Caucasian ethnicity. Methods: The study comprised 24 patients who had been diagnosed with AVMD via indirect fundus ophthalmoscopy and presented with a dome-shaped appearance between the retinal pigment epithelium and photoreceptors on their spectral-domain optical coherence tomography. They had lesion hyper- autofluorescence on their fundus autofluorescence images and were also investigated for BEST1 and PRPH2 mutations for a probable molecular aetiology. Results: No pathogenic or likely pathogenic mutation was detected in the BEST1 and PRPH2 genes of any of the clinically diagnosed AVDM patients. A heterozygous NM_000322.5:c.938C>T (p.Pro313Leu) variant of the PRPH2 gene was detected in 2 non-consanguineous patients. According to current guidelines, this variant was classified as a 'variant of uncertain significance'. Conclusion: In conclusion, AVMD is a genotypic and phenotypic heterogeneous disease. The genetic aetiology could not be explained by sequencing BEST1 and PRPH2 genes in the AVMD patients; however, the variant of PRPH2 could be a cause of predisposition relevant to the phenotype.

Near-infrared fundus autofluorescence in early age-related macular degeneration

PURPOSE

To describe the patterns on near-infrared fundus autofluorescence in eyes affected by early age-related macular degeneration.

DESIGN

Cross-sectional observational case series.

PARTICIPANTS

A total of 84 eyes of 84 patients suffering from early age-related macular degeneration (>63 μm but <125 μm drusen and no-to-mild retinal pigment epithelium abnormalities) were enrolled.

METHODS

Patients underwent best-corrected visual acuity, biomicroscopy, infrared reflectance, short-wavelength fundus autofluorescence, and near-infrared fundus autofluorescence. Eyes were classified according to different patterns of near-infrared fundus autofluorescence. Main outcome was definition of relative prevalence and features of each near-infrared fundus autofluorescence pattern; secondary outcomes were correlation between near-infrared fundus autofluorescence and short-wavelength fundus autofluorescence and between near-infrared fundus autofluorescence patterns and best-corrected visual acuity.

RESULTS

Four different patterns of near-infrared fundus autofluorescence identified: normal foveal signal (Pattern A, 7%); normal foveal signal with hyperautofluorescent/hypoautofluorescent spots not involving the fovea (Pattern B, 65.5%); hyperautofluorescent/hypoautofluorescent spots involving the fovea (Pattern C, 15.5%); patchy pattern (Pattern D, 12%). best-corrected visual acuity was lower in eyes with foveal signal alteration (Patterns C and D).

CONCLUSION

Near-infrared fundus autofluorescence pattern in early age-related macular degeneration might be suggestive of visual function deterioration when the fovea is involved. Longitudinal studies are warranted to confirm our preliminary results.

QUANTITATIVE ANALYSIS OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN ADULT-ONSET FOVEOMACULAR VITELLIFORM DYSTROPHY

PURPOSE

To quantify the foveal avascular zone area at superficial capillary plexus (SCP) and deep capillary plexus (DCP) and the global, parafoveal, and perifoveal vessel densities at SCP, DCP, and choriocapillaris using optical coherence tomography angiography in patients affected by adult-onset foveomacular vitelliform dystrophy (AOFVD).

METHODS

Twenty eyes of 20 consecutive patients (10 females, 50%) with AOFVD and 20 eyes of 20 healthy controls presenting at the Department of Ophthalmology of San Raffaele Hospital, Milan, Italy were enrolled. All patients underwent a complete ophthalmic examination, including 3-mm × 3-mm optical coherence tomography angiography centered on the macula. The vessel density was calculated in the three plexuses (i.e., SCP, DCP, and choriocapillaris) by mean of image binarization, and foveal avascular zone area was manually outlined at SCP and DCP with ImageJ software.

RESULTS

In the SCP, patients with AOFVD disclosed a significant reduction of global (P < 0.001), parafoveal (P = 0.0017), and perifoveal (P = 0.0019) vessel density. In the DCP, parafoveal vessel density was higher in patients with AOFVD (P = 0.0026), whereas no significant difference was appreciated for both the global image (P = 0.5) and the perifoveal area (P = 0.5). Patients with AOFVD showed less dense choriocapillaris (P = 0.012) and perifoveal circle (P = 0.0152), whereas no difference was observed in the perifoveal zone (P = 0.07). Foveal avascular zone area was significantly enlarged at the DCP (P = 0.0184), but not at the SCP.

CONCLUSION

Patients with AOFVD have quantitative vascular alterations in all vascular layers.

Quantitative changes in flow density in patients with adult-onset foveomacular vitelliform dystrophy: an OCT angiography study

PURPOSE

To quantitatively compare the flow density, the retinal thickness, and the area of the foveal avascular zone (FAZ) between patients with adult-onset foveomacular vitelliform dystrophy (AOFVD) and a healthy controls.

METHODS

Thirteen eyes (eight patients) with AOFVD and 13 matched eyes (13 patients) without any ocular pathology were included in this study. A 6 × 6 mm optical coherence tomography angiography (OCTA) scan was performed for every included eye. The flow density (superficial retinal vascular layer, deep retinal vascular layer and choriocapillary layer), retinal thickness and FAZ (superficial retinal vascular layer and deep retinal vascular layer) were subsequently analyzed.

RESULTS

The mean flow density was decreased in the AOFVD patients in all measured vascular layers. The difference from the control group was statistically significant in the parafoveal sector of the deep retinal vascular layer (P = 0.02), and a clear trend was found in the superficial retinal vascular layer (P = 0.05). Both groups had comparable FAZs in the superficial and deep retinal vascular layers. The retinal thickness values were higher in the fovea (P = 0.840) and lower in the parafoveal sectors (P = 0.125). The difference was significant in the superior parafoveal sector (P = 0.034).

CONCLUSIONS

Flow densities as measured by OCTA are decreased in the superficial retinal vascular layer and the deep retinal vascular layer in patients with AOFVD. These findings could be helpful for diagnosing and understanding the pathogenesis of this disease.

Microperimetric evaluation in patients with adult-onset foveomacular vitelliform dystrophy

Introduction:

To compare mean best-corrected visual acuity (BCVA), retinal sensitivity (RS), and bivariate contour ellipse area (BCEA) in patients with adult-onset foveomacular vitelliform dystrophy (AOFVD) and healthy subjects (HSs), reporting also functional disease-related changes in the different stages of the AOFVD disease.

Materials and Methods:

In this observational cross-sectional study, a total of 19 patients (30 eyes; 12 female and 7 male) with AOFVD were enrolled, and 30 patients (30 eyes; 16 female and 14 male) were recruited as age-matched control group (74.36 ± 9.17 years vs. 71.83 ± 6.99 years respectively, P = 0.11). All patients underwent a complete ophthalmologic examination, fundus autofluorescence and fluorescein angiography, spectral-domain optical coherence tomography and microperimetry (MP)-1 analysis. The data collection included mean BCVA, mean RS measured by means of MP-1, BCEA, and central retinal thickness.

Results:

All the functional parameters (BCVA, RS, and BCEA) were significantly worse in AOFVD group than HS. Subgroup analysis showed that the most significant functional changes, quantified by mean BCVA, RS, and BCEA, were in the atrophic stage (P = 0.03, P = 0.01, and P = 0.001, respectively). All the functional parameters were well correlated in the different stages.

Conclusions:

This study further confirms the good visual prognosis in the AOFVD eyes. Fixation stability measurement using BCEA demonstrates good evaluation of visual performance integrating traditional functional parameters. It may also serve for further rehabilitative purposes in atrophic eyes.

Multimodal imaging of foveal cavitation in retinal dystrophies

PURPOSE

Inherited retinal dystrophies and cone dysfunction syndromes may show a sharp hyporeflective interruption in the outermost retinal layers on optical coherence tomography (OCT), known as foveal cavitation (FC). The aim of the study was to describe the morpho-functional features of FC in patients affected by retinal dystrophies by means of multimodal imaging.

METHODS

A consecutive series of patients affected by FC were prospectively recruited for the study. Patients underwent short-wavelength (SW) and near-infraRed (NIR) fundus autofluorescence (FAF), spectral domain OCT (SD-OCT), microperimetry (MP), and multifocal electroretinogram (mfERG). Mean size of FC on OCT was correlated with best-corrected visual acuity (BCVA).

RESULTS

Overall, 15 patients (30 eyes) were enrolled. Mean age was 38.2 ± 14.5 years (range: 10-60), with nine females (60 %). Mean BCVA was 0.5 ± 0.4 LogMAR. SD-OCT revealed focal loss of outer retinal layers and disruption of inner segment ellipsoid zone. Vertical height of FC (mean 27.77 ± 18.77 μm) was indirectly related to BCVA; complete forms of FC, with total loss of outer OCT bands, showed a poorer visual outcome. The FC size on NIR-FAF turned out to be larger with respect to SD-OCT and SW-FAF.

CONCLUSION

Our data indicate that the presence of FC worsens functional outcome in patients affected by retinal disorders; complete and higher lesions are associated with a worse morpho-functional prognosis in these eyes.

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.

Fundus autofluorescence patterns in Best vitelliform macular dystrophy

PURPOSE

To provide a systematic classification of fundus autofluorescence (FAF) patterns in patients affected by Best vitelliform macular dystrophy.

DESIGN

Cross-sectional prospective study.

METHODS

Patients affected by Best vitelliform macular dystrophy at different stages of the disease were prospectively enrolled from January 2012 to July 2013. Eighty eyes of 40 patients were included in the study. All patients underwent a complete ophthalmologic examination, including genetic characterization, short-wavelength FAF, and near-infrared FAF. Main outcome measures were the recognition of the FAF patterns in the different stages and the identification of a relationship between FAF patterns and best-corrected visual acuity (BCVA).

RESULTS

Six FAF patterns for both short-wavelength and near-infrared FAF were identified, including normal, hyper-autofluorescent, hypo-autofluorescent, patchy, multifocal, and spoke-like patterns. Applying Gass's classification for defining consecutive stages of Best vitelliform macular dystrophy (namely vitelliform, pseudohypopyon, vitelliruptive, atrophic, and cicatricial) identified no pattern as stage-specific. Patchy patterns had the highest prevalence. A statistically significant difference (Kruskal-Wallis ANOVA) was found among hyper-autofluorescent, patchy, and hypo-autofluorescent patterns, both in short-wavelength (P = .001) and near-infrared FAF (P = .001). Hyper-autofluorescent and hypo-autofluorescent patterns were associated with better and worse BCVA, respectively.

CONCLUSIONS

Six main patterns on both short-wavelength and near-infrared FAF were identified in Best vitelliform macular dystrophy. No FAF pattern can be considered stage-specific. Although a difference in the BCVA among the FAF patterns was registered, only a longitudinal study designed to evaluate the clinical and FAF modifications over the follow-up will help clarify the prognostic implications of each FAF pattern.

Near-Infrared Fundus Autofluorescence in Multiple Evanescent White-Dot Syndrome

Purpose

To report the near-infrared fundus autofluorescence (NIR-FAF) pattern in 2 cases of multiple evanescent white-dot syndrome (MEWDS).

Methods

Three consecutive patients with MEWDS underwent a complete ophthalmologic examination, including color photograph, blue-light fundus autofluorescence, NIR-FAF, fluorescein angiography, and indocyanine green angiography (ICGA). Main outcome measure was the identification of NIR-FAF pattern.

Results

Fluorescein angiography showed patchy hyperfluorescence of the whitish dots. Indocyanine green angiography showed hypofluorescent spots throughout the examination. Blue-light fundus autofluorescence disclosed a speckled pattern without extension to the foveal area, whereas NIR-AF showed several hypoautofluorescent lesions involving also the fovea, which corresponded to the whitish dots visible on biomicroscopy and to the hypofluorescent lesions detectable on ICGA.

Conclusions

Near-infrared fundus autofluorescence is characterized by hypoautofluorescent spots corresponding to the inflammatory lesions typical of MEWDS and can be considered as a valuable noninvasive technique to diagnose and monitor patients with MEWDS.

Near infrared autofluorescence imaging of retinal diseases

Near infrared autofluorescence (excitation 787 nm, emission >800 nm) is a non-invasive imaging technology that provides information on the distribution of melanin within the retinal pigment epithelial cell/choroid complex. This review contains an introduction to near infrared autofluorescence imaging methods. Characteristics of near infrared imaging in a variety of retinal diseases, including age-related macular degeneration, choroidal nevus, retinal degenerations, retinal dystrophies, central serous chorioretinopathy, pseudoxanthoma elasticum and chloroquine retinopathy, are summarized.

Retro-mode imaging and fundus autofluorescence with scanning laser ophthalmoscope of retinal dystrophies

Background

Retinal dystrophies display a considerably wide range of phenotypic variability, which can make diagnosis and clinical staging difficult. The aim of the study is to analyze the contribution of retro-mode imaging (RMI) and fundus autofluorescence (FAF) to the characterization of retinal dystrophies.

Methods

Eighteen consecutive patients affected by retinal dystrophies underwent a complete ophthalmological examination, including best corrected visual acuity with ETDRS charts, blue-light fundus autofluorescence, (BL-FAF), near-infrared fundus autofluorescence (NIR-FAF), and RMI. The primary outcome was the identification of abnormal patterns on RMI. The secondary outcome was the correlation with the findings on BL-FAF and NIR-FAF.

Results

Overall, the main feature of RMI is represented by a pseudo-3D pattern of all the lesions at the posterior pole. More specifically, any accumulation of material within the retina appears as an area of elevation of different shape and size, displaying irregular and darker borders. No precise correlations between RMI, BL-AF, and NIR-AF imaging was found.

Conclusions

RMI and FAF appear to be useful tools for characterizing retinal dystrophies. Non-invasive diagnostic tools may yield additional information on the clinical setting and the monitoring of the patients.