UNASSIGNED: Extraocular electrical stimulation is known to provide neuroprotection for retinal cells in retinal and optic nerve diseases. Currently, the treatment approach requires patients to set up extraocular electrodes and stimulate potentially weekly due to the lack of an implantable stimulation device. Hence, a minimally-invasive implant was developed to provide chronic electrical stimulation to the retina, potentially improving patient compliance for long-term use. The aim of the present study was to determine the surgical and stimulation safety of this novel device designed for neuroprotective stimulation.
UNASSIGNED: Eight normally sighted adult feline subjects were monocularly implanted in the suprachoroidal space in the peripheral retina for 9-39 weeks. Charge balanced, biphasic, current pulses (100 μA, 500 µs pulse width and 50 pulses/s) were delivered continuously to platinum electrodes for 3-34 weeks. Electrode impedances were measured hourly. Retinal structure and function were assessed at 1-, 2-, 4-, 6- and 8-month using electroretinography, optical coherence tomography and fundus photography. Retina and fibrotic thickness were measured from histological sections. Randomized, blinded histopathological assessments of stimulated and non-stimulated retina were performed.
UNASSIGNED: All subjects tolerated the surgical and stimulation procedure with no evidence of discomfort or unexpected adverse outcomes. The device position was stable after a post-surgery settling period. Median electrode impedance remained within a consistent range (5-10 kΩ) over time. There was no change in retinal thickness or function relative to baseline and fellow eyes. Fibrotic capsule thickness was equivalent between stimulated and non-stimulated tissue and helps to hold the device in place. There was no scarring, insertion trauma, necrosis, retinal damage or fibroblastic response in any retinal samples from implanted eyes, whilst 19% had a minimal histiocytic response, 19% had minimal to mild acute inflammation and 28% had minimal to mild chronic inflammation.
UNASSIGNED: Chronic suprathreshold electrical stimulation of the retina using a minimally invasive device evoked a mild tissue response and no adverse clinical findings. Peripheral suprachoroidal electrical stimulation with an implanted device could potentially be an alternative approach to transcorneal electrical stimulation for delivering neuroprotective stimulation.

UNASSIGNED: We investigated the natural history of retinal dystrophy owing to variants in the MYO7A gene.
UNASSIGNED: Fifty-three patients (mean age, 33.6 ± 16.7 years) with Usher syndrome owing to biallelic, mostly pathogenic, variants in MYO7A underwent baseline and two annual follow-up visits. Best-corrected visual acuity (BCVA), semiautomatic kinetic visual field, full-field electroretinogram, color fundus imaging, microperimetry, spectral-domain optical coherence tomography, and fundus autofluorescence were assessed.
UNASSIGNED: At baseline, all patients presented with decreased BCVA (66.4 ± 17.9 Early Treatment Diabetic Retinopathy score and 59.5 ± 21.7 Early Treatment Diabetic Retinopathy score, in the better- and worse-seeing eyes, respectively), restricted semiautomatic kinetic visual field (III4e area, 3365.8 ± 4142.1°2; 4176.4 ± 4400.3°2) and decreased macular sensitivity (9.7 ± 9.9 dB; 9.0 ± 10.2 dB). Spectral-domain optical coherence tomography revealed reduced central macular thickness (259.6 ± 63.0 µm; 250.7 ± 63.3 µm) and narrowed ellipsoid zone band width (2807.5 ± 2374.6 µm; 2615.5 ± 2370.4 µm). Longitudinal analyses (50 patients) showed a significant decrease of BCVA in better-seeing eyes, whereas no changes were observed in worse-seeing eyes for any parameter. BCVA, semiautomatic kinetic visual field (III4e and V4e) and macular sensitivity were related significantly to age at baseline. Hyperautofluorescent foveal patch (16 eyes [31.4%]) and abnormal central hypoautofluorescence (9 eyes [17.6%]) were significantly associated with worse morphological and functional read-outs compared with the hyperautofluorescent ring pattern (22 eyes [43.1%]).
UNASSIGNED: Our European multicentric study offers the first prospective longitudinal analysis in one of the largest cohorts of MYO7A patients described to date, confirming the slow disease progression. More important, this study emphasizes the key role of fundus autofluorescence patterns in retinal impairment staging and advocates its adoption as an objective biomarker in patient selection for future gene therapy clinical trials.

OBJECTIVE: This article studies the relationship between structural changes according to the findings of optical coherence tomography (OCT) and OCT angiography (OCTA), microperimetry (MP), multifocal electroretinography (mfERG) parameters in topographically corresponding areas of the macular region in idiopathic full-thickness macular holes (FTMH).
METHODS: OCT, OCTA, MP and mfERG were performed in 14 eyes with FTMH stages I-IV according to Gass. In 13 points at a distance of 0-2.5°, 2.5-5.0°, and 5.0-10.0° from the fixation point, the light sensitivity (LS), amplitude and latency of the P1 component were compared with the size of the hole, the area of cystic changes (CC) at the level of the inner nuclear layer (INL) and the outer plexiform layer and Henle fiber layer complex (OPL+HFL), vessel density in the superficial and deep capillary plexus (SCP and DCP).
RESULTS: LS and P1 component amplitude were significantly reduced at a distance of up to 5.0° from the fixation point. LS correlates with the apical and basal diameter of the hole (R> -0.53), the area of CC in the INL (R> -0.62) and the OPL+HFL complex (R> -0.55), the density of vessels in the SCP at a distance of up to 2.5° from the fixation point (R>0.51) and in the DCP at a distance of up to 5° from the fixation point (R>0.49). The P1 amplitude correlates with the basal diameter of the hole (R= -0.38), the area of CC in the INL and the OPL+HFL complex (R> -0.33) and vessel density in the SCP (R=0.37) at a distance of up to 2.5° from the fixation point, as well as vessel density in the DCP at a distance of up to 5° from the fixation point (R=0.47). Vessel density in the DCP is significantly lower in the presence of CC in the retina (p<0.001).
CONCLUSIONS: In FTMH, there is a relationship between bioelectrical activity and LS, and structural disorders, capillary perfusion in different layers of the retina. A multimodal topographically oriented approach allows studying the relationship between structural and functional parameters in individual points of the retina and can be used in monitoring of FTMH after surgical treatment.
UNASSIGNED: Изучить взаимосвязь структурных изменений по данным оптической когерентной томографии (ОКТ) и ОКТ-ангиографии (ОКТ-А) и показателей микропериметрии (МП), мультифокальной электроретинографии (мфЭРГ) в топографически соответствующих областях макулярной области при идиопатических сквозных макулярных разрывах (СМР).
UNASSIGNED: На 14 глазах с СМР I—IV стадии по Gass проведены ОКТ, ОКТ-А, МП, мфЭРГ. В 13 точках на удалении 0—2,5°, 2,5—5,0° и 5,0—10,0° от точки фиксации сопоставлены световая чувствительность (СЧ), амплитуда и латентность компонента Р1 с размерами разрыва, площадью кистозных изменений (КИ) на уровне внутреннего ядерного слоя (ВЯС) и комплекса наружного плексиформного слоя и слоя Генле (НПС + СГ), плотностью сосудов в поверхностном и глубоком капиллярном сплетении (ПКС и ГКС).
UNASSIGNED: СЧ и амплитуда компонента P1 значимо снижены на удалении до 5,0° от точки фиксации. СЧ коррелирует с апикальным и базальным размером разрыва (R> –0,53), площадью КИ в ВЯС (R> –0,62) и комплексе НПС + СГ (R> –0,55), плотностью сосудов в ПКС на удалении до 2,5° от точки фиксации (R>0,51) и в ГКС на удалении до 5° от точки фиксации (R>0,49). Амплитуда P1 коррелирует с базальным диаметром разрыва (R= –0,38), площадью КИ в ВЯС и комплексе НПС + СГ (R> –0,33) и плотностью сосудов в ПКС (R=0,37) на удалении до 2,5° от точки фиксации, а также плотностью сосудов в ГКС на удалении до 5° от точки фиксации (R=0,47). Плотность сосудов в ГКС значимо ниже при наличии КИ в сетчатке (p<0,001).
UNASSIGNED: При СМР существует взаимосвязь между биоэлектрической активностью и СЧ и структурными нарушениями, капиллярной перфузией в различных слоях сетчатки. Мультимодальный топографически ориентированный подход позволяет изучить взаимосвязь структурных и функциональных показателей в отдельных точках сетчатки и может быть использован при наблюдении за СМР после хирургического лечения.

BACKGROUND: There are serious complications associated with hyaluronic acid (HA) facial injections, including vision impairment due to retinal artery ischemia. In this study, we put forth a clinically relevant model of retinal ischemia and reperfusion in rabbit. We used this to verify the efficacy of hyaluronidase intra-artery thrombolysis in the treatment of hyaluronic acid-induced retinal artery occlusion.
METHODS: Retinal artery ischemia was induced by injecting HA into the ophthalmic artery (OA) of adult chinchilla rabbit, and reperfusion was achieved by intra-artery thrombolysis therapy with hyaluronidase following 60 min and 4 h of occlusion. Digital subtraction angiography (DSA) and fundus fluorescein angiography (FFA) were used to evaluate blood flow in the retina. Electroretinogram (ERG), hematoxylin and eosin staining and transmission electron microscope were used to evaluate the structure and function of the retina after ischemia and reperfusion following 60 min and 4 h of occlusion.
RESULTS: DSA and FFA images confirmed occlusion of the ophthalmic and central retinal arteries, as well as reperfusion after hyaluronidase thrombolysis. ERG indicated retinal dysfunction following ischemia, and thrombolysis partially rescued its impairment following 4 h of occlusion. Hematoxylin and eosin staining and TUNEL staining revealed ischemia-induced histological damages in the retina at different time windows, and hyaluronidase thrombolysis partially mitigated these damages.
CONCLUSIONS: We report a method to establish a HA-induced retinal artery occlusion animal model. Hyaluronidase intra-artery thrombolysis was used to recanalize the embolized OA at different time points. Using our method, we achieved retinal reperfusion, and an improvement was observed in the visual function of rabbits after hyaluronidase thrombolysis following 4 h of occlusion. We believe that hyaluronidase intra-artery thrombolysis is an effective method to treat HA-induced retinal artery occlusion in clinic.
METHODS: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

OBJECTIVE: Ataxia-telangiectasia (A-T) is an autosomal recessive disorder characterized by progressive neurological deficits, including prominent oculomotor dysfunction. We report 5 cases of eye movement assessment in children 9-15 years old with A-T.
METHODS: Three different oculomotor tasks (gaze holding, visually guided saccades and visual search) were used, and video-oculography was performed. Additionally, the scale for the assessment and rating of ataxia (SARA) score was used to assess severity of the cerebellar ataxia.
RESULTS: Unstable gaze holding, nystagmus and saccadic intrusions were found. In addition to psychophysiological assessment results, we provide quantitative analysis of oculomotor activity, revealing a specific abnormal oculomotor pattern, consisting of (i) marked saccade hypermetria, (ii) unstable gaze holding, and (iii) gaze-evoked nystagmus.
CONCLUSIONS: Our study opens the prospect to evaluate efficacy and safety of alternative methods for supporting the patient and improving his/her life quality.

In this work, we introduce a diurnal rodent, the Mongolian gerbil (Meriones unguiculatus) (MG) as an alternative to study retinal cone system physiology and pathophysiology in mice. The cone system is of particular importance, as it provides high-acuity and color vision and its impairment in retinal disorders is thus especially disabling. Despite their nocturnal lifestyle, mice are currently the most popular animals to study cone-related diseases due to the high availability of genetically modified models. However, the potential for successful translation of any cone-related results is limited due to the substantial differences in retinal organization between mice and humans. Alternatively, there are diurnal rodents such as the MG with a higher retinal proportion of cones and a macula-like specialized region for improved visual resolution, the visual streak. The focus of this work was the evaluation of the MG\'s cone system functionality using full-field electroretinography (ERG), together with a morphological assessment of its retinal/visual streak organization via angiography, optical coherence tomography (OCT), and photoreceptor immunohistochemistry. We found that rod system responses in MGs were comparable or slightly inferior to mice, while in contrast, cone system responses were much larger, more sensitive, and also faster than those in the murine counterparts, and in addition, it was possible to record sizeable ON and OFF ERG components. Morphologically, MG cone photoreceptor opsins were evenly distributed throughout the retina, while mice show a dorsoventral M- and S-opsin gradient. Additionally, each cone expressed a single opsin, in contrast to the typical co-expression of opsins in mice. Particular attention was given to the visual streak region, featuring a higher density of cones, elongated cone and rod outer segments (OSs), and an increased thickness of the inner and outer retinal layers in comparison to peripheral regions. In summary, our data render the MG a supreme model to investigate cone system physiology, pathophysiology, and to validate potential therapeutic strategies in that context.

OBJECTIVE: To analyze the genetic findings, clinical spectrum, and natural history of Best vitelliform macular dystrophy (BVMD) in a cohort of 222 children and adults.
METHODS: Single-center retrospective, consecutive, observational study.
METHODS: Patients with a clinical diagnosis of BVMD from pedigrees with a likely disease-causing monoallelic sequence variant in the BEST1 gene.
METHODS: Data were extracted from electronic and physical case notes. Electrophysiologic assessment and molecular genetic testing were analyzed.
METHODS: Molecular genetic test findings and clinical findings including best-corrected visual acuity (BCVA), choroidal neovascularization (CNV) rates, and electrophysiologic parameters.
RESULTS: Two hundred twenty-two patients from 141 families were identified harboring 69 BEST1 variants. Mean age at presentation was 26.8 years (range, 1.3-84.8 years) and most patients (61.5%) demonstrated deterioration of central vision. Major funduscopic findings included 128 eyes (30.6%) with yellow vitelliform lesions, 78 eyes (18.7%) with atrophic changes, 49 eyes (11.7%) with fibrotic changes, 48 eyes (11.5%) with mild pigmentary changes, and 43 eyes (10.3%) showing a vitelliruptive appearance. Mean BCVA was 0.37 logarithm of the minimum angle of resolution (logMAR; Snellen equivalent, 20/47) for the right eye and 0.33 logMAR (Snellen equivalent, 20/43) for the left eye at presentation, with a mean annual loss rate of 0.013 logMAR and 0.009 logMAR, respectively, over a mean follow-up of 9.7 years. Thirty-seven patients (17.3%) received a diagnosis of CNV over a mean follow-up of 8.0 years. Eyes with CNV that received treatment with an anti-vascular endothelial growth factor (VEGF) agent showed better mean BCVA compared with eyes that were not treated with an anti-VEGF agent (0.28 logMAR [Snellen equivalent, 20/38] vs. 0.62 logMAR [Snellen equivalent, 20/83]). Most eyes exhibited a hyperopic refractive error (78.7%), and 13 patients (6.1%) received a diagnosis of amblyopia. Among the 3 most common variants, p.(Ala243Val) was associated with a later age of onset, better age-adjusted BCVA, and less advanced Gass stages compared with p.(Arg218Cys) and p.(Arg218His).
CONCLUSIONS: BVMD shows a wide spectrum of phenotypic variability. The disease is very slowly progressive, and the observed phenotype-genotype correlations allow for more accurate prognostication and counselling.
BACKGROUND: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Retinitis pigmentosa (RP) is a heterogeneous disease and the main cause of vision loss within the group of inherited retinal diseases (IRDs). IRDs are a group of rare disorders caused by mutations in one or more of over 280 genes which ultimately result in blindness. Modifier genes play a key role in modulating disease phenotypes, and mutations in them can affect disease outcomes, rate of progression, and severity. Our previous studies have demonstrated that the nuclear hormone receptor 2 family e, member 3 (Nr2e3) gene reduced disease progression and loss of photoreceptor cell layers in RhoP23H-/- mice. This follow up, pharmacology study evaluates a longitudinal NR2E3 dose response in the clinically relevant heterozygous RhoP23H mouse. Reduced retinal degeneration and improved retinal morphology was observed 6 months following treatment evaluating three different NR2E3 doses. Histological and immunohistochemical analysis revealed regions of photoreceptor rescue in the treated retinas of RhoP23H+/- mice. Functional assessment by electroretinogram (ERG) showed attenuated photoreceptor degeneration with all doses. This study demonstrates the effectiveness of different doses of NR2E3 at reducing retinal degeneration and informs dose selection for clinical trials of RhoP23H-associated RP.

Early pioneering studies by Autrum on terrestrial arthropods first revealed that the visual systems of arthropods reflected their lifestyles and habitats. Subsequent studies have examined and confirmed Autrum\'s hypothesis that visual adaptions are driven by predator-prey interactions and activity cycles, with rapidly moving predatory diurnal species generally possessing better temporal resolution than slower moving nocturnal species. However, few studies have compared the vision between diurnal herbivores and nocturnal predators. In this study, the visual physiology of a nocturnal fast-moving predatory crab, the Atlantic ghost crab (Ocypode quadrata) and a diurnal herbivorous crab, the mangrove tree crab (Aratus pisonii), was examined. Spectral sensitivity, irradiance sensitivity and temporal resolution of the crabs were quantified using the electroretinogram (ERG), while the spatial resolution was calculated utilizing morphological methods. Both O. quadrata and A. pisonii had a single dark-adapted spectral sensitivity peak (494 and 499 nm, respectively) and chromatic adaptation had no effect on their spectral sensitivity, indicating that both species have monochromatic visual systems. The temporal resolution of O. quadrata was not significantly different from that of A. pisonii, but O. quadrata did possess a significantly greater spatial resolution and irradiance sensitivity. Both species possess an acute zone in the anterior region of their eyes. The data presented in this study will aid in the current understanding of the correlation between visual physiology and the life history of the animal.

OBJECTIVE: To explore the role of choroidopathy in diabetic retinopathy (DR) by investigating the correlation between alterations of choroidal vessel and photoreceptors during the early stage of DR.
METHODS: We performed a cross-sectional comparison of diabetic patients without DR (NDR group; n=16) and those with mild nonproliferative diabetic retinopathy (NPDR group; n=39). Optical coherence tomography (OCT) images of choroidal vessel alterations and photoreceptor structures were evaluated using the choroidal vascularity index (CVI) and adjusted ellipsoid zone (EZ) reflectivity, respectively. To evaluate the function of cone photoreceptors, the fundamental, harmonic amplitudes, the parameters S and Rmp3 were calculated from the electroretinogram (ERG). These factors were compared between groups. The correlation between the CVI and parameters describing the function and structure of the photoreceptors was evaluated.
RESULTS: The significant decrease was observed in the CVI in the NPDR group compared to the NDR group (0.67 ± 0.04 vs. 0.70 ± 0.06; p = 0.028), but not in the adjusted EZ reflectivity or ERG parameters. In NPDR group and merging the 2 groups, CVI was moderately positively correlated with the fundamental amplitude obtained by the flicker ERG (NPDR only: r = 0.506; p = 0.001; merge the 2 groups: r = 0.423; p = 0.001), which was regulated by the response of the cone photoreceptors. The CVI was positively and moderately correlated with the logS (NPDR only: r = 0.462; p = 0.003; merge the 2 groups: r = 0.355; p = 0.008), indicating the sensitivity of cone cell light transduction.
CONCLUSIONS: Compared to eyes without DR, CVI decreased representing choroidal vascular changes in eyes with mild NPDR. These changes may be related to the functional impairment of cone photoreceptors, especially phototransduction sensitivity, as the DR develops.