Fundus autofluorescence patterns in Best vitelliform macular dystrophy

Künstliche Intelligenz (KI) zur Früherkennung von Netzhauterkrankungen

Künstliche Intelligenz (KI) hat sich zu einem transformativen Werkzeug auf dem Gebiet der Augenheilkunde entwickelt und revolutioniert die Diagnose und Behandlung von Krankheiten. Diese Arbeit gibt einen umfassenden Überblick über KI-Anwendungen bei verschiedenen Netzhauterkrankungen und zeigt ihr Potenzial, die Effizienz von Vorsorgeuntersuchungen zu erhöhen, Frühdiagnosen zu erleichtern und die Patientenergebnisse zu verbessern. Wir erklären die grundlegenden Konzepte der KI, einschließlich des maschinellen Lernens (ML) und des Deep Learning (DL), und deren Anwendung in der Augenheilkunde und heben die Bedeutung von KI-basierten Lösungen bei der Bewältigung der Komplexität und Variabilität von Netzhauterkrankungen hervor. Wir gehen auch auf spezifische Anwendungen der KI im Zusammenhang mit Netzhauterkrankungen wie diabetischer Retinopathie (DR), altersbedingter Makuladegeneration (AMD), makulärer Neovaskularisation, Frühgeborenen-Retinopathie (ROP), retinalem Venenverschluss (RVO), hypertensiver Retinopathie (HR), Retinopathia pigmentosa, Morbus Stargardt, Morbus Best (Best’sche vitelliforme Makuladystrophie) und Sichelzellenretinopathie ein. Wir konzen­trieren uns auf die aktuelle Landschaft der KI-Technologien, einschließlich verschiedener KI-Modelle, ihrer Leistungsmetriken und klinischen Implikationen. Darüber hinaus befassen wir uns mit den Herausforderungen und Schwierigkeiten bei der Integration von KI in die klinische Praxis, einschließlich des «Black-Box-Phänomens», der Verzerrungen bei der Darstellung von Daten und der Einschränkungen im Zusammenhang mit der ganzheitlichen Bewertung von Patienten. Abschließend wird die kollaborative Rolle der KI an der Seite des medizinischen Fachpersonals hervorgehoben, wobei ein synergetischer Ansatz für die Erbringung von Gesundheitsdienstleistungen befürwortet wird. Es wird betont, wie wichtig es ist, KI als Ergänzung und nicht als Ersatz für menschliche Expertise einzusetzen, um ihr Potenzial zu maximieren, die Gesundheitsversorgung zu revolutionieren, Ungleichheiten in der Gesundheitsversorgung zu verringern und die Patientenergebnisse in der sich entwickelnden medizinischen Landschaft zu verbessern.

Best Vitelliform Macular Dystrophy Natural History Study Report 2: Fundus Autofluorescence and OCT

PURPOSE

To analyze the retinal imaging findings and natural history of Best vitelliform macular dystrophy (BVMD).

DESIGN

Single-center retrospective, consecutive, observational study.

PARTICIPANTS

Patients with a clinical diagnosis of BVMD, from pedigrees with a likely disease-causing monoallelic variant in BEST1.

METHODS

Data were extracted from electronic and physical case notes. Retinal imaging with OCT and fundus autofluorescence (FAF) was analyzed cross-sectionally and longitudinally.

MAIN OUTCOME MEASURES

Qualitative and quantitative OCT and FAF analysis.

RESULTS

Two hundred twenty-two patients (127 men) from 141 families were included. Mean central retinal thickness on OCT at baseline was 337.2 μm for the right eye and 341.1 μm for the left eye, with a mean annual thickness loss of 5.7 and 5.2 μm, respectively. The presence of the OCT features: previtelliform lesion, solid vitelliform lesion, vitelliform lesion with subretinal fluid, and focal choroidal excavation were associated with a better mean visual acuity (VA), whereas the presence of intraretinal fluid and atrophy/fibrosis were correlated with a worse mean VA. Fundus autofluorescence showed an area of hyperautofluorescence at the posterior pole in 138 eyes (34.7%), a circumscribed area of hyperautofluorescence superior or superotemporal of the optic nerve head in 53 eyes (13.3%), fibrotic changes in 48 eyes (12.1%), and atrophy in 41 eyes (10.3%).

CONCLUSIONS

Best vitelliform macular dystrophy shows a wide spectrum of phenotypes on OCT and FAF imaging. The slow and variable disease course may pose a challenge in identification of early end points for therapeutic trials aimed at altering kinetics of degeneration.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosures may be found in the Footnotes and Disclosures at the end of this article.

Near-Infrared Autofluorescence: Early Detection of Retinal Pigment Epithelial Alterations in Inherited Retinal Dystrophies

Near-infrared autofluorescence (NIA) is a non-invasive retinal imaging technique used to examine the retinal pigment epithelium (RPE) based on the autofluorescence of melanin. Melanin has several functions within RPE cells. It serves as a protective antioxidative factor and is involved in the phagocytosis of photoreceptor outer segments. Disorders affecting the photoreceptor-RPE complex result in alterations of RPE cells which are detectable by alterations of NIA. NIA allows us to detect early alterations in various chorioretinal disorders, frequently before they are ophthalmoscopically visible and often prior to alterations in lipofuscin-associated fundus autofluorescence (FAF) or optical coherence tomography (OCT). Although NIA and FAF relate to disorders affecting the RPE, the findings for both imaging methods differ and the area involved has been demonstrated to be larger in NIA compared to FAF in several disorders, especially inherited retinal dystrophies (IRDs), indicating that NIA detects earlier alterations compared to FAF. Foveal alterations can be much more easily detected using NIA compared to FAF. A reduced subfoveal NIA intensity is the earliest sign of autosomal dominant Best disease, when FAF and OCT are still normal. In other IRDs, a preserved subfoveal NIA intensity is associated with good visual acuity. So far, the current knowledge on NIA in IRD has been presented in multiple separate publications but has not been summarized in an overview. This review presents the current knowledge on NIA in IRD and demonstrates NIA biomarkers.

Artificial Intelligence (AI) for Early Diagnosis of Retinal Diseases

Artificial intelligence (AI) has emerged as a transformative tool in the field of ophthalmology, revolutionizing disease diagnosis and management. This paper provides a comprehensive overview of AI applications in various retinal diseases, highlighting its potential to enhance screening efficiency, facilitate early diagnosis, and improve patient outcomes. Herein, we elucidate the fundamental concepts of AI, including machine learning (ML) and deep learning (DL), and their application in ophthalmology, underscoring the significance of AI-driven solutions in addressing the complexity and variability of retinal diseases. Furthermore, we delve into the specific applications of AI in retinal diseases such as diabetic retinopathy (DR), age-related macular degeneration (AMD), Macular Neovascularization, retinopathy of prematurity (ROP), retinal vein occlusion (RVO), hypertensive retinopathy (HR), Retinitis Pigmentosa, Stargardt disease, best vitelliform macular dystrophy, and sickle cell retinopathy. We focus on the current landscape of AI technologies, including various AI models, their performance metrics, and clinical implications. Furthermore, we aim to address challenges and pitfalls associated with the integration of AI in clinical practice, including the "black box phenomenon", biases in data representation, and limitations in comprehensive patient assessment. In conclusion, this review emphasizes the collaborative role of AI alongside healthcare professionals, advocating for a synergistic approach to healthcare delivery. It highlights the importance of leveraging AI to augment, rather than replace, human expertise, thereby maximizing its potential to revolutionize healthcare delivery, mitigate healthcare disparities, and improve patient outcomes in the evolving landscape of medicine.

Multimodal imaging in Best Vitelliform Macular Dystrophy: Literature review and novel insights

Best Vitelliform Macular Dystrophy (BVMD) is a dominantly inherited retinal disease caused by dominant variants in the BEST1 gene. The original classification of BVMD is based on biomicroscopy and color fundus photography (CFP); however, advancements in retinal imaging provided unique structural, vascular, and functional data and novel insights on disease pathogenesis. Quantitative fundus autofluorescence studies informed us that lipofuscin accumulation, the hallmark of BVMD, is unlikely to be a primary effect of the genetic defect. It could be due to a lack of apposition between photoreceptors and retinal pigment epithelium in the macula with subsequent accumulation of shed outer segments over time. Optical Coherence Tomography (OCT) and adaptive optics imaging revealed that vitelliform lesions are characterized by progressive changes in the cone mosaic corresponding to a thinning of the outer nuclear layer and then disruption of the ellipsoid zone, which are associated with a decreased sensitivity and visual acuity. Therefore, an OCT staging system based on lesion composition, thus reflecting disease evolution, has been recently developed. Lastly, the emerging role of OCT Angiography proved a greater prevalence of macular neovascularization, the majority of which are non-exudative and develop in late disease stages. In conclusion, effective diagnosis, staging, and clinical management of BVMD will likely require a deep understanding of the multimodal imaging features of this disease.

Clinical Correlation Between Optical Coherence Tomography Biomarkers and Retinal Sensitivity in Best Vitelliform Macular Dystrophy

Purpose

To investigate the clinical and imaging features associated with retinal sensitivity in Best vitelliform macular dystrophy (BVMD).

Methods

This was a cross-sectional, single-center, observational study. Each patient underwent optical coherence tomography (OCT), near-infrared fundus autofluorescence, and OCT angiography. Macular integrity assessment microperimetry under mesopic conditions was performed to obtain retinal sensitivity thresholds from 68 testing points in the central macula. Structural OCT was used to classify BVMD lesions into four types according to their composition: vitelliform, mixed, subretinal fluid, and atrophy. Multilevel, mixed-effects linear regression was used to determine the factors associated with retinal sensitivity.

Results

The study included 57 eyes of 30 patients with BVMD, 48 of which (84%) were in a clinical stage. Mean retinal sensitivity varied according to the composition of the lesion: the vitelliform type registering the highest (22 ± 4.1 dB), followed by mixed (18.73 ± 2.7 dB), subretinal fluid (15.68 ± 4.2 dB), and atrophy types (11.85 ± 4.6 dB). The factors most strongly associated with mean retinal sensitivity in BVMD proved to be the OCT lesion type and outer nuclear layer thickness.

Conclusions

Retinal sensitivity in BVMD is influenced by lesion composition and outer nuclear layer thickness. Further studies with long-term follow-up are warranted to examine retinal sensitivity over time and to validate retinal sensitivity changes as biomarkers for BVMD.

Translational Relevance

Assessing retinal sensitivity in BVMD provides a new instrument in the clinical characterization of the disease and offers the opportunity to identify imaging biomarkers for use as outcome measures in future clinical trials.

Deep learning to distinguish Best vitelliform macular dystrophy (BVMD) from adult-onset vitelliform macular degeneration (AVMD)

Initial stages of Best vitelliform macular dystrophy (BVMD) and adult vitelliform macular dystrophy (AVMD) harbor similar blue autofluorescence (BAF) and optical coherence tomography (OCT) features. Nevertheless, BVMD is characterized by a worse final stage visual acuity (VA) and an earlier onset of critical VA loss. Currently, differential diagnosis requires an invasive and time-consuming process including genetic testing, electrooculography (EOG), full field electroretinogram (ERG), and visual field testing. The aim of our study was to automatically classify OCT and BAF images from stage II BVMD and AVMD eyes using a deep learning algorithm and to identify an image processing method to facilitate human-based clinical diagnosis based on non-invasive tests like BAF and OCT without the use of machine-learning technology. After the application of a customized image processing method, OCT images were characterized by a dark appearance of the vitelliform deposit in the case of BVMD and a lighter inhomogeneous appearance in the case of AVMD. By contrast, a customized method for processing of BAF images revealed that BVMD and AVMD were characterized respectively by the presence or absence of a hypo-autofluorescent region of retina encircling the central hyperautofluorescent foveal lesion. The human-based evaluation of both BAF and OCT images showed significantly higher correspondence to ground truth reference when performed on processed images. The deep learning classifiers based on BAF and OCT images showed around 90% accuracy of classification with both processed and unprocessed images, which was significantly higher than human performance on both processed and unprocessed images. The ability to differentiate between the two entities without recurring to invasive and expensive tests may offer a valuable clinical tool in the management of the two diseases.

Disease expression caused by different variants in the BEST1 gene: genotype and phenotype findings in bestrophinopathies

Purpose:

To analyse the spectrum of clinical features and molecular genetic data in a series of patients carrying likely disease-associated variants in the BEST1 gene.

Methods:

Retrospective observational analysis of clinical data extracted from the medical records of visual function, multimodal imaging and electrophysiology of 62 eyes of 31 patients. Molecular genetic analysis was performed by means of panel-based NGS or Sanger sequencing.

Results:

The spectrum of variants in the BEST1 gene comprised 19 different variants and three of which are novel. Fundus photographs and OCT images allowed categorization of 52 eyes as Best vitelliform macular dystrophy (BVMD) with stages 1 to 5 and 10 eyes with autosomal recessive bestrophinopathy (ARB), with more severe phenotype. One patient was shown to be heterozygous for a variant, which has so far been described only in ARB, but this patient had the BVMD phenotype. There was no significant progression of the visual acuity during the follow-up period of 5 years both in BVMD and ARB. The most prevalent pattern of fundus autofluorescence (FAF) in BVMD was ‘patchy’. There were diverse visual field defects in static automated perimetry (SAP) depending on the stage. The Arden ratio was significantly lower in ARB patients and in eyes with stage 5 of BVMD.

Conclusions:

The genotype does not always predict the phenotype in patients with BVMD and ARB; however, having two mutations in the BEST1 gene causes a more severephenotype. FAFhelped to distinguish ARB from BVMD. Most of the observed eyesdidnotprogressfunctionallyduringthefollow-up.ARBandtheatrophicstageof BVMD as the disease end-stage had the worst visual functions and EOG results.

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.

Multimodal Imaging Characteristics of Quiescent Type 1 Neovascularization in Best Vitelliform Macular Dystrophy

This case report of a 38-year-old man with bilateral Best vitelliform macular dystrophy (BVMD) presents bilateral quiescent type 1 neovascularizations (NV) detected by optical coherence angiography (OCTA) and their multimodal imaging characteristics. It was emphasized that this kind of quiescent and asymptomatic NV may be present in nearly every stage of BVMD and it was concluded that OCTA is a noninvasive, easy, and rapid method that is superior to other imaging methods in detecting them.

SHORT-TERM MODIFICATIONS OF ELLIPSOID ZONE IN BEST VITELLIFORM MACULAR DYSTROPHY

PURPOSE

To assess ellipsoid zone (EZ) alterations in Best vitelliform macular dystrophy using spectral-domain optical coherence tomography.

METHODS

Prospective, observational case series. Forty-three patients (43 eyes) underwent complete ophthalmological examination at baseline and at 24 months: best-corrected visual acuity (BCVA), biomicroscopy, fundus photography, and spectral-domain optical coherence tomography were performed. Acquisition protocol included 19-line raster scan. Alterations in EZ were marked on spectral-domain optical coherence tomography, and the area was manually calculated on a near-infrared reflectance image. Three patterns were identified: A (decrease >0.25 mm2), B (±0.25 mm2), and C (increase >0.25 mm2). Primary outcome was to describe different patterns of EZ alteration. Secondary outcomes included their correlation with BCVA and the description of a central optically preserved islet.

RESULTS

At baseline, altered EZ was identified in 40 eyes. Worse BCVA significantly correlated with larger EZ alterations but not with lesion extension on fundus photograph. Only "pattern-C" eyes unveiled BCVA worsening at follow-up. Optically preserved islet was detected in 16 eyes (37%), disclosing significantly better vision; its disappearance at follow-up (n = 7; 44% of 16 eyes) correlated with a decrease in BCVA.

CONCLUSION

The assessment of EZ status might represent a valuable functional marker in Best vitelliform macular dystrophy because stable alterations and the maintenance of a central optically preserved islet are associated with better visual acuity.

Progression of Atrophy and Visual Outcomes in Extensive Macular Atrophy with Pseudodrusen-like Appearance

Purpose

Design

Participants

Methods

Main Outcome Measures

Results

Conclusions

Optical Coherence Tomography Angiography Quantitative Assessment of Macular Neovascularization in Best Vitelliform Macular Dystrophy

Purpose

To describe quantitative characteristics of macular neovascularization (MNV) in vitelliform macular dystrophy (VMD) patients by means of optical coherence tomography angiography (OCTA).

Methods

The study design was a prospective case series. All patients underwent complete ophthalmologic assessment, optical coherence tomography, and OCTA. The quantitative OCTA parameters examined included vessel tortuosity and vessel dispersion of the MNV. The primary outcome was OCTA characterization of MNV in VMD. Secondary outcomes included the evolution of MNV over the follow-up.

Results

A total of 78 eyes were recruited for the study. MNV was identified in 50 eyes (64%) at baseline and in 51 eyes (65%) at the end of the follow-up (mean follow-up, 24.7 ± 9.7 months). MNV was detected in four out of the 30 eyes classified as stages 2 and 3 (13%), showing exudative manifestations and undergoing ranibizumab treatment, leading to clinical stabilization. OCTA detected MNV in 46 out of 48 eyes (96%) classified as stages 4 and 5, showing no evidence of exudative manifestation. All of the non-exudative MNVs were merely observed over the follow-up and received no treatment. At the end of the follow-up, 47 out of 48 eyes displayed MNV (98%). Non-exudative MNVs remained stable over the follow-up. Statistically significant differences were found when comparing vessel tortuosity and vessel dispersion in the two MNV subforms.

Conclusions

VMD is characterized by two MNV subforms. Exudative MNV is rare and may develop in the early stages of the disease, in association with bleeding and fluid formation. Non-exudative MNV develops very commonly in the advanced stage of VMD, without any exudative manifestation.

Multimodal imaging in subclinical best vitelliform macular dystrophy

BACKGROUND

To analyse multimodal imaging alterations in the subclinical form of best vitelliform macular dystrophy (BVMD).

METHODS

The study was designed as an observational, cross-sectional case series. Eleven eyes of 7 subclinical patients with BVMD and 12 age-matched and sex-matched controls were included. Multimodal imaging included fundus blue-light autofluorescence, near-infrared autofluorescence (NIR-AF), structural optical coherence tomography (OCT) and OCT angiography (OCTA). The quantitative analysis included the calculation of the following parameters: vessel density (VD), vessel tortuosity (VT), vessel dispersion (Vdisp), vessel rarefaction (VR), foveal avascular zone (FAZ) area, reflectivity of the outer retinal bands and choriocapillaris porosity (CCP).

RESULTS

Mean best-corrected visual acuity was 0.0±0.0 LogMAR in both groups. The round central hypoautofluorescent alteration on NIR-AF corresponded to a significant reflectivity attenuation of the outer retinal bands on structural OCT (0.55±0.18 vs 0.75±0.08; p<0.001). VD, VT, VR and Vdisp were normal compared with controls (all p>0.05). The FAZ area turned out to be significantly restricted at the level of the deep capillary plexus in subclinical BVMD eyes (p<0.001). Furthermore, quantitative OCTA revealed a significant central increase of CCP, compared with controls (18.25±2.43 vs 4.58±1.36; p<0.001).

CONCLUSIONS

The subclinical stage of BVMD is characterised by significant alterations of the outer retinal bands and the choriocapillaris. Quantitative multimodal imaging assessment suggests that subclinical BVMD is affected by the functional impairment of the outer retinal structures, leading to an alteration in melanin and growth factor production.

IMAGING OF VITELLIFORM MACULAR LESIONS USING POLARIZATION-SENSITIVE OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

To examine the involvement of the retinal pigment epithelium (RPE) in the presence of vitelliform macular lesions (VML) in Best vitelliform macular dystrophy (BVMD), autosomal recessive bestrophinopathy, and adult-onset vitelliform macular degeneration using polarization-sensitive optical coherence tomography (PS-OCT).

METHODS

A total of 35 eyes of 18 patients were imaged using a PS-OCT system and blue light fundus autofluorescence imaging. Pathogenic mutations in the BEST1 gene, 3 of which were new, were detected in all patients with BVMD and autosomal recessive bestrophinopathy.

RESULTS

Polarization-sensitive optical coherence tomography showed a characteristic pattern in all three diseases with nondepolarizing material in the subretinal space consistent with the yellowish VML seen on funduscopy with a visible RPE line below it. A focal RPE thickening was seen in 26 eyes under or at the edge of the VML. Retinal pigment epithelium thickness outside the VML was normal or mildly thinned in patients with BVMD and adult-onset vitelliform macular degeneration but was diffusely thinned or atrophic in patients with autosomal recessive bestrophinopathy. Patients with autosomal recessive bestrophinopathy showed sub-RPE fibrosis alongside the subretinal VML. Polarization-sensitive optical coherence tomography was more reliable in assessing the localization and the integrity of the RPE than spectral domain OCT alone. On spectral domain OCT, identification of the RPE was not possible in 19.4% of eyes. Polarization-sensitive optical coherence tomography allowed for definite identification of the location of VML in respect to the RPE in all eyes, since it provides a tissue-specific contrast.

CONCLUSION

Polarization-sensitive optical coherence tomography confirms in vivo the subretinal location of VML and is useful in the assessment of RPE integrity.

Reviewing the Role of Ultra-Widefield Imaging in Inherited Retinal Dystrophies

Inherited retinal dystrophies (IRD) are a heterogeneous group of rare chronic disorders caused by genetically determined degeneration of photoreceptors and retinal pigment epithelium cells. Ultra-widefield (UWF) imaging is a useful diagnostic tool for evaluating retinal integrity in IRD, including Stargardt disease, retinitis pigmentosa, cone dystrophies, and Best vitelliform dystrophy. Color or pseudocolor and fundus autofluorescence images obtained with UWF provide previously unavailable information on the retinal periphery, which correlates well with visual field measurement or electroretinogram. Despite unavoidable artifacts of the UWF device, the feasibility of investigations in infants and in patients with poor fixation makes UWF imaging a precious resource in the diagnostic armamentarium for IRD.

Natural course of the vitelliform stage in best vitelliform macular dystrophy: a five-year follow-up study

PURPOSE

The vitelliform stage is the typical phenotypic manifestation of Best vitelliform macular dystrophy (BVMD). As yet, no study has focused specifically on the clinical changes occurring in the vitelliform stage over the follow-up.

METHODS

The survey takes the form of a prospective observational study with a 5-year follow-up. Twenty-one eyes of 11 patients in the vitelliform stage were examined annually. The primary outcome was the identification of the changes in the vitelliform lesion over a 5-year follow-up. Secondary outcomes included changes in structural optical coherence tomography (OCT) parameters and the correlation with the BCVA variation over the follow-up.

RESULTS

Spectral domain OCT at baseline showed one subform characterized by solid vitelliform deposition, in 81% of eyes, and another subform characterized by a combination of solid deposition and subretinal fluid, in 19% of eyes. Overall, 62% of eyes showed an increase in the area of vitelliform deposition. Once the maximal area was reached, a progressive flattening of the vitelliform deposition took place, with subsequent flattening of the vitelliform lesion and formation of subretinal fluid. Hyperreflective foci (HF) increased in number as long as the vitelliform area continued to expand, with no variation in HF when the vitelliform lesion flattened or the subretinal fluid formed.

CONCLUSIONS

The vitelliform stage reveals more subforms with clinical variations over the follow-up. Our data suggest that the substage before the flattening of the lesion, thus before the so-called subretinal fluid accumulates and when the visual acuity is still high, might offer the best opportunity for an optimal therapeutic approach.

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.

INTRARETINAL HYPERREFLECTIVE FOCI IN BEST VITELLIFORM MACULAR DYSTROPHY

PURPOSE

To report on the presence of hyperreflective foci (HF) on spectral domain optical coherence tomography in patients with Best vitelliform macular dystrophy (BVMD), and to describe the relationship between HF and stages of the disease.

METHODS

Consecutive patients diagnosed with BVMD were enrolled in a prospective cross-sectional study. All patients and control subjects underwent a complete ophthalmologic examination, including best-corrected visual acuity and spectral domain optical coherence tomography.

MAIN OUTCOME MEASURE

identification of HF in BVMD. Secondary outcome: assessment of the HF in each stage and correlation with best-corrected visual acuity.

RESULTS

Overall, 75 eyes of 39 patients were included in the study (Stage 1: 13%, Stage 2: 43%, Stage 3: 15%, Stage 4: 21%, and Stage 5: 8%). On spectral domain optical coherence tomography assessment, intraretinal HF were present in 83% of all eyes, in 91% of eyes affected by clinical BVMD (Stages 2-5) and in 100% of patients in Stages 4 and 5. In 46% of clinically diseased eyes, HF were localized in the fovea and in correspondence with the BVMD lesions at the level of the outer nuclear layer and outer plexiform layer. Hyperreflective foci were present in 16% of control eyes. Mean number of HF in eyes affected by clinical BVMD stood at 7.67 ± 7.35. These were predominantly small HF (6.23 ± 6.14, P < 0.001) localized in the outer nuclear layer (5.19 ± 5.38, P = 0.001) and presented largely in the extrafoveal, rather than the foveal area (5.21 ± 5.57 vs 2.46 ± 2.73, P = 0.001). Analysis of HF distribution revealed that the control group and Stage 1 eyes had the fewest HF; Stage 4 displayed a significant increase in the number of HF compared with Stages 2 and 3; Stage 5 also showed an increased number of HF, although this difference was statistically significant only with Stage 3 eyes. The best-corrected visual acuity was negatively related to the number of HF, with best-corrected visual acuity deteriorating as the number of HF increased in Stages 2 to 5 (P < 0.001).

CONCLUSION

This study describes the presence of HF in BVMD using spectral domain optical coherence tomography. Our data suggest that HF identification is correlated with the progression of the disease and could represent a useful biomarker of BVMD.

Altered ellipsoid zone reflectivity and deep capillary plexus rarefaction correlate with progression in Best disease

AIMS

To evaluate the effects of neurovascular damage in patients with the typical vitelliform lesion of Best vitelliform macular dystrophy (BVMD) in the attempt to identify different progression patterns.

METHODS

Prospective, observational case series. Patients in the vitelliform stage of BVMD and healthy controls underwent complete ophthalmological examination on a yearly basis, including best-corrected visual acuity (BCVA), biomicroscopy, optical coherence tomography (OCT) and OCT angiography (OCT-A). 4.5×4.5 mm OCT-A slabs were imported into ImageJ software and their vessel density (VD) was calculated. Similarly, the ellipsoid zone (EZ) was manually outlined and the reflectivity was measured above the vitelliform lesion and in the 500 µm external to it. Retinal pigment epithelium-Bruch's membrane complex was taken as internal reference.

RESULTS

34 eyes (24 patients) and 34 matched controls were included in the study. Mean follow-up was of 28.4±5.8 months, with 12 eyes showing signs of stage progression at the end follow-up. The EZ overlying the vitelliform lesion and in the peri-lesional area disclosed a significant reduction in reflectivity when compared with the foveal and para-foveal EZ of controls, respectively. VD resulted meaningfully decreased only at the deep capillary plexus. Of notice, more extensive EZ (reflectivity <0.7) and vascular alterations (VD <0.4) at baseline strongly correlated with worse BCVA and were associated with a more rapid progression at follow-up.

CONCLUSIONS

Both EZ reflectivity and VD at deep capillary plexus may prove valuable biomarkers to assess BVMD severity and detect progression. In this view, 'rapid progressors' might benefit the most from timely genetic therapies in the future.

Chromatic pupilloperimetry for objective diagnosis of Best vitelliform macular dystrophy

Purpose

To determine the pupil response of Best vitelliform macular dystrophy (BVMD) patients for focal blue and red light stimuli presented at 76 test points in a 16.2° visual field (VF) using a chromatic pupilloperimeter.

Methods

An observational study was conducted in 16 participants: 7 BVMD patients with a heterozygous BEST1 mutation and 9 similar-aged controls. All participants were tested for best-corrected visual acuity, chromatic pupilloperimetry and Humphrey perimetry. Percentage of pupil contraction (PPC), maximal pupil contraction velocity (MCV) and latency of MCV (LMCV) were determined.

Results

The mean PPC and MCV recorded in BVMD patients in response to red stimuli were lower by >2 standard errors (SEs) from the mean of controls in 47% and 43% of VF test points, respectively. The mean PPC and MCV recorded in the patients in response to blue stimuli were lower by >2 SEs from the mean of controls in 36% and 24% of VF test points, respectively. The patients’ mean and median MCV recorded in response to red light correlated with their Humphrey mean deviation score (r=−0.714, P=0.071 and r=−0.821, P=0.023, respectively) and visual acuity (r=0.709, P=0.074 and r=0.655, P=0.111, respectively). A substantially shorter mean LMCV was recorded in BVMD patients compared to controls in 54% and 93% of VF test points in response to red and blue light, respectively. Receiver operating characteristic analysis for LMCV in response to red light identified a test point at the center of the VF with high diagnostic accuracy (area under the curve of 0.94).

Conclusion

Chromatic pupilloperimetry may potentially be used for objective noninvasive assessment of rod and cone cell function in different locations of the retina in BVMD patients.

Imaging retinal melanin: a review of current technologies

The retinal pigment epithelium (RPE) is essential to the health of the retina and the proper functioning of the photoreceptors. The RPE is rich in melanosomes, which contain the pigment melanin. Changes in RPE pigmentation are seen with normal aging and in diseases such as albinism and age-related macular degeneration. However, most techniques used to this day to detect and quantify ocular melanin are performed ex vivo and are destructive to the tissue. There is a need for in vivo imaging of melanin both at the clinical and pre-clinical level to study how pigmentation changes can inform disease progression. In this manuscript, we review in vivo imaging techniques such as fundus photography, fundus reflectometry, near-infrared autofluorescence imaging, photoacoustic imaging, and functional optical coherence tomography that specifically detect melanin in the retina. These methods use different contrast mechanisms to detect melanin and provide images with different resolutions and field-of-views, making them complementary to each other.

SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY FEATURES IN DIFFERENT STAGES OF BEST VITELLIFORM MACULAR DYSTROPHY

PURPOSE

To provide a systematic classification of findings regarding the different stages of vitelliform macular dystrophy on spectral domain optical coherence tomography (SD-OCT).

METHODS

Ninety-four eyes of 47 patients were recruited in a prospective cross-sectional study. All patients underwent a complete ophthalmologic examination, including best-corrected visual acuity using Early Treatment Diabetic Retinopathy Study (ETDRS) charts, biomicroscopy, and SD-OCT. The findings assessed included vitelliform material, neurosensory detachment, status of external limiting membrane, ellipsoid zone and retinal pigment epithelium, choroidal excavation, foveal cavitation, choroidal neovascularization, vitreomacular traction, and macular hole. The primary outcome measure was the identification of SD-OCT findings in each vitelliform macular dystrophy stage. Secondary outcomes included the correlations between SD-OCT features and visual acuity changes.

RESULTS

The outer retinal layers (external limiting membrane, ellipsoid zone, and retinal pigment epithelium) were found to be more commonly disrupted in Stages 2 to 4 (range: 86%-100%), whereas their absence was more typical of Stage 5 (71%-86%). Vitelliform material was found in 100% of Stages 2 and 3, 93% of Stage 4, and interestingly in 43% of Stage 5. Eyes characterized by vitelliform material showed a greater correlation with higher best-corrected visual acuity than eyes without it (0.35 logarithm of the minimum angle of resolution vs. 0.80 ± 0.36 logarithm of the minimum angle of resolution, approximately 20/45 and 20/125 Snellen equivalent, respectively) (t = 3.726, P < 0.05). Moreover, its absence was associated with a best-corrected visual acuity of 0.5 logarithm of the minimum angle of resolution or worse (approximately 20/63 Snellen equivalent; P < 0.05). Subretinal fluid was more common in Stages 3 and 4 (72.7% and 75%, respectively) than Stages 2 and 5 (P = 0.004). Eyes with subretinal fluid were significantly associated with a visual acuity of 0.2 logarithm of the minimum angle of resolution or worse (approximately 20/32 Snellen equivalent; P = 0.04).

CONCLUSION

Spectral domain optical coherence tomography assessment primarily indicates an outer retinal layer disruption in Stages 2 to 4, along with the presence of vitelliform material extending into the more advanced clinical stages too. Eyes characterized by the persistence of vitelliform material show better best-corrected visual acuity. Future investigations based on a longitudinal follow-up are warranted to correlate SD-OCT modifications with functional responses to identify SD-OCT indicators for prognostic and therapeutic purposes.

Retinal Vascular Impairment in Best Vitelliform Macular Dystrophy Assessed by Means of Optical Coherence Tomography Angiography

PURPOSE

To evaluate vascular abnormalities at superficial (SCP) and deep (DCP) capillary plexuses and choriocapillaris (CC) in patients with Best vitelliform macular dystrophy (BVMD) by means of optical coherence tomography angiography (OCT-A).

DESIGN

Cross-sectional case series.

METHODS

Sixty-six eyes of 33 patients with BVMD (16 male) and 33 controls were consecutively enrolled. Patients were subdivided into classic stages and underwent best-corrected visual acuity (BCVA), fundus autofluorescence and spectral domain-optical coherence tomography, and 4.5 × 4.5-mm swept-source OCT-A. Choroidal neovascularization (CNV) and capillary dilations were qualitatively assessed by 2 masked ophthalmologists. Each OCT-A slab was imported into ImageJ 1.50 and digitally binarized for quantitative analyses. Foveal avascular zone (FAZ) area was measured manually; vessel density was then quantified after the exclusion of the FAZ pixels. Eyes classified as stages 3 and 4 were evaluated together.

RESULTS

Nineteen eyes (28.8%) revealed capillary dilations at DCP, 15 of which were in stages 1 and 2. Interestingly, CNV was detected in 24 eyes (36.4%). Quantitative analysis disclosed that stages 3-4 and 5 carry significant impairment at both SCP (P < .0001 and P = .02, respectively) and DCP (P < .0001 and P = .0004, respectively) compared to controls. FAZ area was enlarged at the DCP (P = .001). Only DCP vessel density significantly correlated with the stage and BCVA.

CONCLUSIONS

Patients with BVMD show significant vascular impairment at both superficial and deep retinal plexuses, correlating with functional outcomes. These findings, especially at DCP, may improve our understanding about the pathogenesis, and may help in predicting BVMD treatment efficacy.

Juvenile Macular Degenerations

In this article, we review the following 3 common juvenile macular degenerations: Stargardt disease, X-linked retinoschisis, and Best vitelliform macular dystrophy. These are inherited disorders that typically present during childhood, when vision is still developing. They are sufficiently common that they should be included in the differential diagnosis of visual loss in pediatric patients. Diagnosis is secured by a combination of clinical findings, optical coherence tomography imaging, and genetic testing. Early diagnosis promotes optimal management. Although there is currently no definitive cure for these conditions, therapeutic modalities under investigation include pharmacologic treatment, gene therapy, and stem cell transplantation.

Optical coherence tomography in Best vitelliform macular dystrophy

PURPOSE

To analyze spectral-domain optical coherence tomography (SD-OCT)-specific findings in the different stages of vitelliform macular dystrophy (VMD).

METHODS

Thirty-seven patients were prospectively recruited. All the patients underwent a complete ophthalmologic examination, including best-corrected visual acuity (BCVA), biomicroscopy, and SD-OCT. The examined findings were vitelliform material, neurosensory detachment, intraretinal hyperreflective foci, and the status of external limiting membrane, ellipsoid zone, and retinal pigment epithelium. The primary outcome was the stratification of SD-OCT findings in each VMD stage. Secondary outcomes included the description of different characteristics related to intraretinal hyperreflective foci.

RESULTS

Outer retinal layers were preserved almost exclusively in stage 1 (range 70%-100%), whereas their disruption and absence were typical of stages 2 to 4 (83%-100%) and stage 5 (67%-83%), respectively. Vitelliform material was found always in stages 2 and 3, 89% of stage 4, and rarely in stage 5 (33%). Neurosensory detachment was to some extent representative of stages 3 and 4 (80% and 72%, respectively) when compared with the other stages (p<0.001). Hyperreflective foci (16% of all eyes) demonstrated a progressive increase across stages 2 to 4, with slightly reduced figure in stage 5. These foci were located in the outer nuclear and plexiform layers, showed different sizes, and were not associated with a visual acuity reduction (p = 0.64).

CONCLUSIONS

A progressive deterioration of the outer retinal layers was noticeable in more advanced stages of VMD. The reduction of vitelliform material from stage 3 to 4 was paralleled by an increased evidence of neurosensory detachment. Although showing different size and location, hyperreflective foci did not correlate with worse BCVA.

Bestrophin 1 and retinal disease

Mutations in the gene BEST1 are causally associated with as many as five clinically distinct retinal degenerative diseases, which are collectively referred to as the "bestrophinopathies". These five associated diseases are: Best vitelliform macular dystrophy, autosomal recessive bestrophinopathy, adult-onset vitelliform macular dystrophy, autosomal dominant vitreoretinochoroidopathy, and retinitis pigmentosa. The most common of these is Best vitelliform macular dystrophy. Bestrophin 1 (Best1), the protein encoded by the gene BEST1, has been the subject of a great deal of research since it was first identified nearly two decades ago. Today we know that Best1 functions as both a pentameric anion channel and a regulator of intracellular Ca²⁺ signaling. Best1 is an integral membrane protein which, within the eye, is uniquely expressed in the retinal pigment epithelium where it predominantly localizes to the basolateral plasma membrane. Within the brain, Best1 expression has been documented in both glial cells and astrocytes where it functions in both tonic GABA release and glutamate transport. The crystal structure of Best1 has revealed critical information about how Best1 functions as an ion channel and how Ca²⁺ regulates that function. Studies using animal models have led to critical insights into the physiological roles of Best1 and advances in stem cell technology have allowed for the development of patient-derived, "disease in a dish" models. In this article we review our knowledge of Best1 and discuss prospects for near-term clinical trials to test therapies for the bestrophinopathies, a currently incurable and untreatable set of diseases.

Fundus autofluorescence applications in retinal imaging

Fundus autofluorescence (FAF) is a relatively new imaging technique that can be used to study retinal diseases. It provides information on retinal metabolism and health. Several different pathologies can be detected. Peculiar AF alterations can help the clinician to monitor disease progression and to better understand its pathogenesis. In the present article, we review FAF principles and clinical applications.

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.