Recessive MECR pathogenic variants cause an LHON-like optic neuropathy.

BACKGROUND: Leber's hereditary optic neuropathy (LHON) is a mitochondrial disorder characterised by complex I defect leading to sudden degeneration of retinal ganglion cells. Although typically associated with pathogenic variants in mitochondrial DNA, LHON was recently described in patients carrying biallelic variants in nuclear genes DNAJC30, NDUFS2 and MCAT. MCAT is part of mitochondrial fatty acid synthesis (mtFAS), as also MECR, the mitochondrial trans-2-enoyl-CoA reductase. MECR mutations lead to a recessive childhood-onset syndromic disorder with dystonia, optic atrophy and basal ganglia abnormalities. METHODS: We studied through whole exome sequencing two sisters affected by sudden and painless visual loss at young age, with partial recovery and persistent central scotoma. We modelled the candidate variant in yeast and studied mitochondrial dysfunction in yeast and fibroblasts. We tested protein lipoylation and cell response to oxidative stress in yeast. RESULTS: Both sisters carried a homozygous pathogenic variant in MECR (p.Arg258Trp). In yeast, the MECR-R258W mutant showed an impaired oxidative growth, 30% reduction in oxygen consumption rate and 80% decrease in protein levels, pointing to structure destabilisation. Fibroblasts confirmed the reduced amount of MECR protein, but failed to reproduce the OXPHOS defect. Respiratory complexes assembly was normal. Finally, the yeast mutant lacked lipoylation of key metabolic enzymes and was more sensitive to H2O2 treatment. Lipoic Acid supplementation partially rescued the growth defect. CONCLUSION: We report the first family with homozygous MECR variant causing an LHON-like optic neuropathy, which pairs the recent MCAT findings, reinforcing the impairment of mtFAS as novel pathogenic mechanism in LHON.

Geographic Atrophy-associated Intraretinal Neovascularization (GAIN): A novel clinical entity.

KEY MESSAGES     : WHAT IS KNOWN : Geographic atrophy could be associated with MNV or other vascular alterations. Intraretinal fluid could be present in GA also without neovascularization. WHAT IS NEW : GAIN is a novel clinical entity characterized by GA and an intraretinal neovascular network. GAIN could be exudative or non-exudative.

OCT risk factors for 2-year foveal involvement in non-treated eyes with extrafoveal geographic atrophy and AMD.

PURPOSE: To assess the relationship of optical coherence tomography (OCT) findings and progression to foveal atrophy in a cohort of eyes with extrafoveal geographic atrophy (GA) and age-related macular degeneration (AMD) at inclusion. METHODS: We retrospectively analyzed 45 participants (45 eyes) with extrafoveal GA at baseline and with 2 years of regular follow-ups. Several OCT qualitative features (i.e., presence of foveal flat pigment epithelium detachment with a thin double layer sign [DLS] and reticular pseudodrusen, GA focality) and quantitative measurements (outer retinal layer thickness, retinal pigment epithelium [RPE] to Bruch's membrane [BM] volume, minimum distance from the central foveal circle, and untransformed GA lesion size area) were assessed at baseline. Logistic regression analyses were carried out to identify independent significant predictors and compute odds ratios (ORs) for the risk of the development of atrophy. RESULTS: At month 24, 26 eyes (57.8%) developed atrophy in the foveal central circle, while 11 eyes (24.4%) developed atrophy in the foveal central point. Significant independent predictive features for the development of atrophy in the foveal central circle included foveal outer retinal thickness (OR, 0.867; p = 0.015), minimum distance from the foveal central circle (OR, 0.992; p = 0.022), and foveal thin DLS (OR, 0.044; p = 0.036). The only independent predictive feature for the development of atrophy in the foveal central point was the presence of foveal thin DLS (OR, 0.138; p = 0.017). CONCLUSIONS: We identified OCT risk factors for 2-year foveal atrophy in eyes with untreated extrafoveal GA at baseline.

Structural OCT and OCT angiography biomarkers associated with the development and progression of geographic atrophy in AMD.

BACKGROUND: Geographic atrophy (GA) is an advanced, irreversible, and progressive form of age-related macular degeneration (AMD). Structural optical coherence tomography (OCT) and OCT angiography (OCTA) have been largely used to characterize this stage of AMD and, more importantly, to define biomarkers associated with the development and progression of GA in AMD. METHODS: Articles pertaining to OCT and OCTA biomarkers related to the development and progression of GA with relevant key words were used to search in PubMed, Researchgate, and Google Scholar. The articles were selected based on their relevance, reliability, publication year, published journal, and accessibility. RESULTS: Previous reports have highlighted various OCT and OCTA biomarkers linked to the onset and advancement of GA. These biomarkers encompass characteristics such as the size, volume, and subtype of drusen, the presence of hyperreflective foci, basal laminar deposits, incomplete retinal pigment epithelium and outer retinal atrophy (iRORA), persistent choroidal hypertransmission defects, and the existence of subretinal drusenoid deposits (also referred to as reticular pseudodrusen). Moreover, biomarkers associated with the progression of GA include thinning of the outer retina, photoreceptor degradation, the distance between retinal pigment epithelium and Bruch's membrane, and choriocapillaris loss. CONCLUSION: The advent of novel treatment strategies for GA underscores the heightened need for prompt diagnosis and precise monitoring of individuals with this condition. The utilization of structural OCT and OCTA becomes essential for identifying distinct biomarkers associated with the initiation and progression of GA.

Long-term predictors of anti-VEGF treatment response in patients with neovascularization secondary to CSCR: a longitudinal study.

PURPOSE: To identify the baseline predictors of anti-VEGF treatment response at 3 years in patients affected by choroidal neovascularization (CNV) secondary to central serous chorioretinopathy (CSCR). METHODS: In this retrospective longitudinal study, medical records of patients diagnosed with CNV secondary to CSCR and treated using anti-VEGF injections between April 2015 and May 2020 were reviewed. The potential qualitative and quantitative predictors of treatment response were identified or measured based on the multimodal imaging examination available for each patient at the baseline, including structural OCT, fluorescein angiography (FA), indocyanine green angiography (ICGA), and OCT-angiography (OCT-A). Univariate and multivariate analyses were performed. RESULTS: Twenty-nine eyes from 29 patients affected by CNV complicating CSCR were included in the study. At the end of the 3-year follow-up, the mean BCVA was 20/50 Snellen equivalent (0.38 ± 0.36 LogMAR), and no significant difference with baseline BCVA (0.37 ± 0.29 LogMAR) was found (p = 0.9). Twenty out of 29 eyes (69%) had active lesions at the end of the follow-up. At multivariate analysis, none of the included features was independently associated with the 3-year BCVA outcome. Pigment epithelium detachment (PED) height (ß = 0.017, p = 0.028) and outer limiting membrane (OLM) preservation at the fovea (ß = -5.637, p = 0.026) were independently associated with the CNV activity at 3 years. CONCLUSION: PED height and OLM obliteration at the fovea might be considered baseline predictors of lesion activity at 3-year follow-up in patients with CNV secondary to CSCR treated with anti-VEGF therapy.

The "triple-layer sign": an optical coherence tomography signature for the detection of non-exudative macular neovascularization.

PURPOSE: To assess the sensitivity and specificity of the "triple layer sign" (TLS) (retinal pigment epithelium (RPE), neovascular tissue, and Bruch's membrane) on structural optical coherence tomography (OCT) images for the diagnosis of treatment-naïve non-exudative type-1 macular neovascularization (NE-MNV) in age-related macular degeneration (AMD). DESIGN: Cross-sectional study. METHODS: Two masked retinal experts evaluated the presence of the TLS in eyes with NE-MNV and controls with an RPE elevation without exudation due to other causes than NE-MNV in AMD [e.g., medium-large drusen, cuticular drusen, basal laminar deposits (BlamD)]. RESULTS: 130 eyes of 98 consecutive patients met the study criteria; 40 eyes of 40 patients satisfied the criteria for being included in the NE-MNV secondary to AMD group (27 females, 13 males, with a mean age of 73.8 ± 8.0 years), and 90 eyes of 58 patients met the criteria to be included in the control group (31 eyes were included in the medium-to-large drusen sub-group, 32 eyes in the cuticular drusen sub-group, and 27 eyes in the BlamD group. The TLS was observed in 39/40 patients with NE-MNV and 8/90 controls. The sensitivity and specificity of the TLS for the diagnosis of NE-MNV were 97% and 91%, respectively. CONCLUSIONS: The TLS on OCT demonstrated high sensitivity and specificity values in detecting treatment-naive type 1 NE-MNV.

Peripapillary hyperreflective ovoid mass-like structures (PHOMS) in patients with acute Leber's hereditary optic neuropathy.

PURPOSE: Peripapillary hyperreflective ovoid mass-like structures (PHOMS) represent an optical coherence tomography (OCT) finding that has been characterized in different forms of pseudopapilledema. The aim of this study was to investigate the prevalence of PHOMS in patients affected by acute LHON using structural OCT, and to provide a detailed description of these findings. METHODS: Patients with a clinical and molecularly confirmed diagnosis of acute LHON (visual loss having occurred less than 6 months) were enrolled from the neuro-ophthalmology clinic at San Raffaele Scientific Institute. Patients had a complete ophthalmologic evaluation, including imaging with structural OCT. RESULTS: Our analysis included 16 patients (21 eyes-8 males and 8 females) with acute LHON. Structural OCT exhibited PHOMS in 12 eyes from 9 patients with a prevalence rate of 57.1%. In a subsequent topographical assessment in the peripapillary area, the most common location of PHOMS was the temporal region (12 out of 12 eyes), while the nasal region was affected in 2 eyes (16.7%). Considering the 12 eyes with PHOMS, mean ± SD temporal peripapillary RNFL thickness was 87.5 ± 28.4 microns. The temporal peripapillary RNFL thickness was significantly lower in eyes without PHOMS (63.7 ± 32.2 microns; P = 0.40). At the 12-month follow-up visit, PHOMS disappeared in 10 out of 12 eyes. CONCLUSIONS: Acute LHON eyes have PHOMS which are mainly confined to the temporal peripapillary sector. PHOMS may represent swelled retinal fibers that have herniated or are in stasis.

THE PROGNOSTIC SIGNIFICANCE OF ACUTE HENLE FIBER LAYER HYPERREFLECTIVITY IN PLACOID DISEASES.

PURPOSE: To investigate the pathophysiology and prognostic significance of acute Henle fiber layer (HFL) hyperreflectivity in placoid diseases by examining its relationship with impaired choroidal flow and persistent photoreceptor disruption. METHODS: Retrospective-prospective observational study on patients with placoid diseases. Indocyanine green angiography and optical coherence tomography were performed during the acute phase and follow-up. Impaired choroidal flow, HFL hyperreflectivity, and persistent ellipsoid zone disruption, their colocalization index, and their associations with initial and final visual acuity were explored. RESULTS: Sixteen eyes from eight patients (mean age, 25.3 ± 6.44 years) were included (median follow-up, 13.5 months). Quantitative analysis revealed significant correlations between areas of impaired choroidal flow, HFL hyperreflectivity, and persistent ellipsoid zone disruption (correlation coefficients of 0.69, 0.63, and 0.46, respectively). Impaired choroidal flow area exceeded HFL hyperreflectivity (P = 0.002) and ellipsoid zone disruption (P = 0.003). A noteworthy 94% nonrandom overlap between HFL hyperreflectivity and ellipsoid zone disruption was observed. Worse initial visual acuity correlated with foveal involvement (P = 0.0002), thicker choroid (P = 0.001), larger impaired choroidal flow areas (P = 0.02), and thinner outer retina post lesion inactivation (P = 0.04). CONCLUSION: Henle fiber layer hyperreflectivity predicted photoreceptor recovery potential in placoid diseases. If HFL hyperreflectivity corresponds to acute HFL damage, it may suggest more severe involvement of the entire photoreceptor length.

RETICULAR PSEUDODRUSEN DISAPPEARANCE AFTER DEVELOPMENT OF MACULAR NEOVASCULARIZATION.

PURPOSE: To explore changes in reticular pseudodrusen (RPD) number and location after the development of macular neovascularization (MNV) in eyes with prior intermediate age-related macular degeneration, focusing on different retinal regions differently affected by MNV. METHODS: This retrospective longitudinal study included intermediate age-related macular degeneration eyes with RPD that developed MNV. Reticular pseudodrusen were assessed at baseline when MNV was diagnosed (MNV stage) and after anti-vascular endothelial growth factor treatment. Three regions of interest were considered: MNV area, subretinal fluid (SRF) area, and a marginal area of 1,000 µm around SRF (marginal zone). Reticular pseudodrusen counts were compared with age- and sex-matched control eyes with RPD that did not develop MNV. RESULTS: Reticular pseudodrusen number exhibited a significant decrease after MNV development in the MNV area (P = 0.048) and in the area with SRF (P = 0.078). A statistically significant decrease was also disclosed in the marginal area around SRF (P = 0.002), associated with larger SRF areas. Control eyes did not show any significant change in the RPD count. CONCLUSION: Reticular pseudodrusen reduction after MNV development suggests a complex interplay involving the MNV itself, the presence of SRF, and trophic changes. The results of this study highlight the role of MNV in retinal nutritional balance and provide intriguing results in the RPD life cycle.

INTERSESSION REPEATABILITY OF READING PERFORMANCE MEASURES IN PATIENTS WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To assess the intersession repeatability of reading performance measures in patients with previously treated neovascular age-related macular degeneration and good best-corrected visual acuity (≥20/40 Snellen). METHODS: Ninety-one patients (91 eyes) with a diagnosis of previously treated neovascular age-related macular degeneration and good best-corrected visual acuity (≥20/40 Snellen) were prospectively enrolled. Reading performance metrics were assessed using Radner charts, and these measurements were repeated after 7 days to obtain the intersession repeatability. To test repeatability, we calculated the intraclass correlation coefficient, the 95% coefficient of repeatability, and the coefficient of variation for each reading parameter: 1) reading acuity (RA-LogRAD); 2) maximal reading speed-words per minute; 3) RA score (RA score-LogRAD); and 4) critical print size-LogRAD. RESULTS: Mean ± standard deviation best-corrected visual acuity was 0.13 ± 0.01 logMAR [range: 0.00-0.30 logMAR]. The intraclass correlation coefficient values indicated a good reliability for all the analyzed metrics (0.901 for RA; 0.859 for max reading speed; 0.906 for RA score; and 0.868 for critical print size). The coefficient of repeatability was 0.2 LogRAD for RA, 63.2 words per minute for max reading speed, 0.2 LogRAD for RA score, and 0.2 LogRAD for critical print size. Coefficient of variation was 5.5% for RA, 8.9% for max reading speed, 5.8% for RA score, and 6.9% for critical print size. CONCLUSION: Reading performance metrics are characterized by good values of intersession repeatability in patients with neovascular age-related macular degeneration with good best-corrected visual acuity. Our findings may grant the employment of such measures in trials assessing the visual outcome in these patients.