Systemic inflammation is increasingly recognized as a potential contributor in sight threatening retinal diseases such as Age-related Macular Degeneration (AMD). Yet, its impact on local eye immune responses and further pathological processes remains poorly understood. This study aims to elucidate the effect of peripheral immune activation on the local complement system, a central component of innate immunity with a dual role in maintaining ocular homeostasis and mediating inflammation, in the mouse retina and retinal pigment epithelium (RPE). Using a systemic lipopolysaccharide (LPS) challenge and a high-resolution proteomic approach, we observed a significant increase in complement factor 3 (C3) production in the RPE and retina 24 h post-injection. Further analysis confirmed the local source of complement signaling in resident cells such as astrocytes and RPE, independently from blood-retina barrier disruption. These findings reveal a direct cross-talk between systemic immune activation and ocular complement activation, and highlight the potential implications of systemic inflammation in the pathogenesis of ocular diseases, underlining the importance of future research into targeted therapies for inflammation-driven conditions.

INTRODUCTION:The aim of the study was to report the phenotype and progression pattern of RP1 retinitis pigmentosa carrying the variant c.2613dupA (p.Arg872Thrfs*2). METHODS:This is a retrospective cohort study from 13 families with confirmed RP1 c.2613dupA (p.Arg872Thrfs*2) variant. Analysis was performed on clinical data including multimodal imaging and visual function tests. Progression rate (PR) was defined as the length of ellipsoid zone (EZ) lost per year and was calculated for all patients. Linear mixed model to predict the diameter of EZ loss as a function of age was applied. RESULTS:Twenty-one patients were included in the study. EZ loss in all patients ranged from 3.8 to 576.0 µm/year (median PR 76.5, IQR 97.6) in right eyes and from 26.6 to 340.7 µm/year (median PR 96.6, IQR 70.3), in left eyes, respectively, with a linear slope of progression for both eyes. The linear mixed model using age as an explanatory variable explained 25% of the variability in PR and showed that male patients had on average a statistically significant smaller EZ diameter at baseline. CONCLUSION:The rate of progression of RP1 as measured by loss of EZ appears to be linear, independent of the age of onset. Furthermore, it appears that male subjects may present with earlier onset of disease as they showed a statistically significant smaller EZ diameter at baseline. Monitoring of EZ loss could be a valid clinical surrogate marker for clinical trials, but possibly sex differences and high variability of phenotypes need to be considered.

Inherited retinal dystrophies (IRDs) are characterized by their high clinical and genetic heterogeneity. Despite significant advances in the identification of genes associated with IRDs, many individuals and families still have not received a definite molecular diagnosis. Here, we performed clinical examinations and conducted genetic testing in five families with IRD. Whole exome sequencing in the five index cases revealed a heterozygous missense variant, c.209G > A, p.(Gly70Glu) in the ARL3 gene (NM_004311.4). A de novo occurrence was demonstrated in one affected individual and autosomal dominant inheritance in nine affected individuals from four families. Their phenotypes displayed variable expressivity, and ranged from rod-cone to cone-rod dystrophy with photophobia. Human induced pluripotent stem cells (hiPSCs) were generated from dermal fibroblasts from the individual with the de novo ARL3 variant and were differentiated to retinal pigment epithelium cells (RPE) and retinal organoids. Immunofluorescence analyses in these models showed decreased INPP5E localization within the cilia of RPE and connecting cilia of retinal organoids, as well as reduced PDE6⍺ in the organoid outer segments, suggesting that the p.(Gly70Glu) variant causes IRD by defective lipidated protein transport in photoreceptors and/or RPE. This is the first study of ARL3 dysfunction in human retinal cells, highlighting its importance for retinal homeostasis, as well as a variability in the clinical presentation of ARL3-associated IRD.

Purpose:Inherited retinal diseases (IRDs) are rare and diverse, posing a diagnostic challenge in ophthalmology. This study aimed to determine whether artificial intelligence (AI)-assisted image processing can improve IRD diagnosis and provide insights into disease characteristics. We used an optical coherence tomography (OCT) segmentation algorithm to characterize retinal features in IRDs. Two control groups were included to enhance the contextual understanding of these features: healthy eyes and eyes with age-related macular degeneration (AMD). An AI-driven classification model was then used to classify the data into disease and control groups. Methods:We analyzed 327 images from 181 patients with IRD and 146 control individuals, including healthy subjects and patients with AMD. IRD cases were stratified into macular and retinal dystrophies. Automated segmentation of six retinal layers and detection of nine biomarkers were performed on retinal OCT images using the AI-based RetinAI Discovery tool. A random forest classifier differentiated macular IRD, retinal IRD, and controls. Results:The model detected IRD with 91% accuracy and achieved 91% accuracy in differentiating macular from retinal IRD. Key OCT features for differentiation included reduced perifoveal photoreceptor and outer nuclear layer thicknesses and increased retinal nerve fiber layer thickness in retinal IRD. Macular IRD featured significant foveal photoreceptor and outer nuclear layer thinning. Conclusions:This study shows that standardized OCT image analysis combined with AI-based classification can accurately detect and stratify IRDs. The model's high accuracy highlights its potential as a reliable diagnostic tool in ophthalmology. Translational Relevance:This AI-assisted OCT evaluation approach enhances ophthalmic diagnostics by improving IRD detection and classification.

Juvenile neuronal ceroid lipofuscinosis (JNCL) is one of the many types of NCLs, which are a group of inherited neurodegenerative lysosomal storage disorders. Type 3, the classic and most common form, is caused by homozygous or compound heterozygous pathogenic variants in the CLN3 gene that encodes a lysosomal transmembrane protein. This yields in unbalanced cellular homeostasis and increased neuronal loss, as the physiological protein is predicted to be a pH regulator and modulator of vesicular transport and fusion [1]. Clinical symptoms mostly present between 5 – 10 years of age and manifest as progressive vision loss and, rarely, seizures. Cognitive and behavioural impairment is thought to appear a few years after the onset of visual impairment [1]. This is, however, not always the case. The aim of this case report is to describe the unusual phenotypic presentation of juvenile NCL3 in a patient of Swiss descent.

This study aims to investigate the effect of a systemic lipopolysaccharide (LPS) stimulus in the course of laser-induced choroidal neovascularization (CNV) in C57BL/6 J mice. A group of CNV-subjected mice received 1 mg/kg LPS via the tail vein immediately after CNV induction. Mouse eyes were monitored in vivo with fluorescein angiography for 2 weeks. In situ hybridization and flow cytometry were performed in the retina at different time points. LPS led to increased fluorescein leakage 3 days after CNV, correlated with a large influx of monocyte-derived macrophages and increase of pro-inflammatory microglia/macrophages in the retina. Additionally, LPS enhanced Vegfα mRNA expression by Glul-expressing cells but not Aif1 positive microglia/macrophages in the laser lesion. These findings suggest that systemic LPS exposure has transient detrimental effects in the course of CNV through activation of microglia/macrophages to a pro-inflammatory phenotype and supports the important role of these cells in the CNV course.

Introduction: The purpose of this project was to explore the current standards of clinical care genetic testing and counseling for patients with inherited retinal diseases (IRDs) from the perspective of leading experts in selected European countries. Also, to gather opinions on current bottlenecks and future solutions to improve patient care. Methods: On the initiative of the European Vision Institute, a survey questionnaire with 41 questions was designed and sent to experts in the field from ten European countries. Each participant was asked to answer with reference to the situation in their own country. Results: Sixteen questionnaires were collected by November 2023. IRD genetic tests are performed in clinical care settings for 80% or more of tested patients in 9 countries, and the costs of genetic tests in clinical care are covered by the public health service to the extent of 90% or more in 8 countries. The median proportion of patients who are genetically tested, the median rate of genetically solved patients among those who are tested, and the median proportion of patients receiving counseling are 51-70%, 61-80%, and 61-80%, respectively. Improving the education of healthcare professionals who facilitate patient referrals to specialized centers, improving access of patients to more thorough genotyping, and increasing the number of available counselors were the most advocated solutions. Conclusion: There is a significant proportion of IRD patients who are not genetically tested, whose genetic testing is inconclusive, or who do not receive counseling. Educational programs, greater availability of state-of-the-art genotyping and genetic counselors could improve healthcare for IRD patients.

Chromosomal abnormalities on the short arm of chromosome 2 in the region p11.2 have been associated with developmental delay, intellectual disability, facial anomalies, abnormal ears, skeletal and genital malformations. Here we describe a patient with a de novo interstitial heterozygous microdeletion on the short arm of chromosome 2 in the region p11.2-p12. He presents with facial dysmorphism characterized by a broad and low root of the nose and low-set protruding ears. Clinical examinations during follow-up visits revealed congenital pendular nystagmus, decreased visual acuity and psychomotor development disorder including intellectual disability. The heterozygous 5 Mb-microdeletion was characterized by an array CGH (Comparative Genomic Hybridization) analysis. In the past two decades, nine patients with microdeletions in this region have been identified by array CGH analysis and were reported in the literature. All these patients show psychomotor development disorder and outer and/or inner ear anomalies. In addition, most of the patients have mild to severe intellectual disability and show facial malformations. We reviewed the literature on PubMed and OMIM using the gene/loci names as search terms in an attempt to identify correlations between genes located within the heterozygous microdeletion and the clinical phenotype of the patient, in order to define a recognizable phenotype for the 2p11.2p12 microdeletion syndrome. We discuss additional symptoms that are not systematically present in all patients and contribute to a heterogeneous clinical presentation of this microdeletion syndrome.

Purpose: To assess the clinical resolution capacities of a novel high-resolution optical coherence tomography (High-Res OCT).Methods: Eight healthy volunteers were included in this observational study. Using the SPECTRALIS High-Res OCT device (Heidelberg Engineering, Heidelberg) macular b scans were taken and compared with b-scans acquired with a SPECTRALIS HRA+OCT device (Heidelberg Engineering, Heidelberg). High-Res OCT scans were also compared with hematoxylin and eosin-stained sections from a human donor retina.Results: High-Res OCT allowed identification of several retinal structures at the cellular and subcellular levels, namely, cell nuclei of ganglion cells, displaced amacrine cells, cone photoreceptors and retinal pigment epithelial cells compared with the commercial device. Rod photoreceptor nuclei were partially detectable. Localization of cell type- specific nuclei were confirmed by histological sections of human donor retina. Additionally, all three plexus of the retinal vasculature could be visualized.Conclusions: SPECTRALIS High-Res OCT device provides improved resolution compared with the conventional SPECTRALIS HRA+OCT device and allows to identify structures at the cellular level, similar to histological sections.Translational Relevance: High-Res OCT shows improved visualization of retinal structures in healthy individuals and can be used to assess individual cells within the retina.

Inherited childhood-onset retinal dystrophies comprise Leber congenital amaurosis (LCA; OMIM #204 000) and juvenile retinitis pigmentosa (RP; OMIM #268000). LCA is considered the more aggressive manifestation due to early loss of central vision and subsequent development of nystagmus, whereas juvenile RP has a later onset in childhood and initially affects the periphery [1], [2]. In 2009, SPATA7 was first identified as a causative gene for both LCA and juvenile RP (OMIM# 604 232) [3].

Abstract Background Clustering of microglia around the vasculature has been reported in the retina and the brain after systemic administration of lipopolysaccharides (LPS) in mice. LPS acts via activation of Toll-like receptor 4 (TRL4), which is expressed in several cell types including microglia, monocytes and vascular endothelial cells. The purpose of this study was to investigate the effect of systemic LPS in the pigmented mouse retina and the involvement of endothelial TLR4 in LPS-induced retinal microglia activation. Methods C57BL/6J, conditional knockout mice that lack Tlr4 expression selectively on endothelial cells (TekCre−posTlr4loxP/loxP) and TekCre−negTlr4loxP/loxP mice were used. The mice were injected with 1 mg/kg LPS via the tail vein once per day for a total of 4 days. Prior to initiation of LPS injections and approximately 5 h after the last injection, in vivo imaging using fluorescein angiography and spectral-domain optical coherence tomography was performed. Immunohistochemistry, flow cytometry, electroretinography and transmission electron microscopy were utilized to investigate the role of endothelial TLR4 in LPS-induced microglia activation and retinal function. Results Activation of microglia, infiltration of monocyte-derived macrophages, impaired ribbon synapse organization and retinal dysfunction were observed after the LPS exposure in C57BL/6J and TekCre−negTlr4loxP/loxP mice. None of these effects were observed in the retinas of conditional Tlr4 knockout mice after the LPS challenge. Conclusions The findings of the present study suggest that systemic LPS exposure can have detrimental effects in the healthy retina and that TLR4 expressed on endothelial cells is essential for retinal microglia activation and retinal dysfunction upon systemic LPS challenge. This important finding provides new insights into the role of microglia–endothelial cell interaction in inflammatory retinal disease.

Refsum disease, also known as heredopathia atactica polyneuritiformis (OMIM 266 500), is a rare genetic disorder that is inherited in an autosomal recessive manner.

Purpose The aim of the study was to describe the clinical and genetic correlation of a c.469 G>A p.(Asp157Asn) heterozygous pathogenic variant in PRPH2 in two siblings of Italian origin. Patients and Methods Both patients underwent ophthalmic examination, electrophysiological testing, autofluorescence imaging, and optical coherence tomography (OCT). Screening for pathogenic variants of the obtained DNA from the family members was carried out. Results The 52-year-old (female, index patient) and 50-year-old (male) siblings had BCVA (OD and OS) of 20/20 and 20/16 (female) and 20/25 and 20/40 (male), respectively, and suffered increased sensitivity to glare. Yellow irregular macular deposits, numerous small irregular hypo- and hyperreflective spots at the posterior pole, a patchy loss of photoreceptors, and retinal pigment epithelium (RPE) in the perifoveal region were seen. Electrophysiology showed dysfunction of rods and cones, with more affected cone dysfunction in the index patient, contrary to the generalised rod dysfunction in the brother of the index patient. The clinical, electrophysiological, and multimodal imaging findings of both siblings pointed towards Stargardt retinopathy with heterogenic presentation. The DNA analysis identified an autosomal dominant c.469 G> A p.(Asp157Asn) heterozygous pathogenic variant in PRPH2 associated with autosomal dominant cone-rod dystrophy and rod-cone dystrophy. PRPH2 codes for peripherin-2, a membrane protein that consists of 346 amino acids. Conclusions Our findings confirm a heterogeneity in clinical presentation associated with pathogenic variants in PRPH2. It may follow either an autosomal dominant or an autosomal recessive mode of inheritance and show a very heterogeneous clinical manifestation of retinal degeneration, e.g., autosomal dominant retinitis pigmentosa male sibling; II-3) and autosomal dominant cone-rod dystrophy (index female sibling; II-2), autosomal dominant macular dystrophy, and also autosomal recessive retinitis pigmentosa.

PURPOSE:The purpose of this study was to investigate the clinical and genetic features of a man and his daughter with posterior polymorphous corneal dystrophy (PPCD), referred to our clinic for Descemet membrane endothelial keratoplasty. No other known relatives were affected.METHODS:Ophthalmic examination and histology, including electron microscopy, were performed. Genetic testing was conducted by means of whole exome sequencing, and variant analysis was achieved by using an internal in silico pipeline. Molecular tests included a dual-luciferase assay.RESULTS:Slowly progressive blurred vision was reported from childhood by the daughter. The father's symptoms started at age 55. Best-corrected visual acuity was reduced in both patients (0.2-0.4). Slit-lamp examination in both patients revealed bilateral corneal clouding with gray endothelial lesions; other family members had no ophthalmological signs. Descemet membrane endothelial keratoplasty was performed uneventfully in both patients. Histology showed thickened Descemet membrane and abnormal endothelium resembling epithelial-like cells. Both patients carried the OVOL2 5' untranslated region NM_021220.4.c.-61G>A variant in the heterozygous state. This change was associated with increased promoter activity and was not present in the unaffected members of the family.CONCLUSIONS:The 5' untranslated region mutation c.-61G>A in OVOL2 has been previously found in 1 individual with PPCD1 and reported as a variant of unknown significance because of insufficient evidence supporting its pathogenicity. Identification of the second family with 2 individuals affected by PPCD1 carrying this change, together with functional data, provides further proofs that it is disease-causing.