Search Results (390)

The miniature (mini) Ossabaw pigs are proposed as a translational preclinical model for testing and developing novel therapeutics for human diseases, including cystic fibrosis, cancer, and metabolic syndrome (MetS). In recent years, pigs have gained similar attention for studying retinal abnormalities and disorders owing to their close resemblance in size, anatomy, vasculature, and pathology to the human eye compared with their rodent counterparts. In our previous study, Ossabaw minipigs fed a Western diet for 10 weeks and followed for 3.5 months exhibited early signs of retinal degeneration and vascular abnormalities, mimicking the early stages of diabetic retinopathy (DR). To further evaluate pathomorphological alterations across neuronal and non-neuronal cell types, the present study comprehensively investigated individual retinal layers using cell-type-specific immunostaining. We found that the Western diet-fed mini pigs had reduced rhodopsin and blue opsins, changes in bipolar and ganglion cells, and reduced density of pre- and post-synaptic connections. Moreover, the retinas of obese mini pigs showed evidence of gliosis and microglial activation. Our findings suggest that a Western diet-induced metabolic disorder exhibits an early neurodegenerative milieu and further demonstrate the suitability of Ossabaw mini pigs as a model for human retinal diseases associated with MetS, such as DR and diabetic macular edema (DME). Full article

Background/Objectives: Refractory macular holes (MHs) that persist after conventional internal limiting membrane (ILM) peeling pose a significant surgical challenge. In this study, we analyzed the anatomical and functional outcomes of epiretinal human amniotic membrane (hAM) transplantation in patients with MHs. Methods: This retrospective study included 10 eyes of 10 patients with refractory MHs. All patients underwent 25-gauge pars plana vitrectomy, epiretinal cryopreserved hAM transplantation, and C3F8 gas tamponade. The large hAM graft was placed over the macula with the stromal side facing the retina. Preoperative and postoperative best-corrected visual acuity (BCVA), optical coherence tomography (OCT) findings, and MH dimensions were recorded. Results: The mean follow-up period was 7 months (range: 3–14 months). The mean preoperative minimum linear diameter and base diameter of the MHs were 715 ± 212 μm and 1114 ± 258 μm, respectively. Anatomical closure was achieved in all patients (100%). Postoperative OCT revealed rearrangement of the inner and other retinal layers in 7 out of 10 patients (70%), with partial restoration of the outer retinal layers. The mean logMAR BCVA improved significantly from 1.60 ± 0.37 preoperatively to 1.00 ± 0.45 postoperatively (p < 0.001). No graft dislocation, rejection, or other significant complications were observed. Conclusions: Our preliminary results suggest that epiretinal human amniotic membrane transplantation is a feasible and promising surgical technique for achieving anatomical closure and functional improvement in refractory macular holes in which conventional ILM peeling has failed. Full article

Background and Objectives: Dementia is an essential neurodegenerative disease with pathologic changes in the central nervous system, but also the retina. To evaluate the diagnostic performance of Spectralis optical coherence tomography (OCT) parameters for mild cognitive impairment (MCI) and mild dementia in an Asian population from Taiwan. Methods: This retrospective cross-sectional study evaluated 43 patients with MCI (mean deviation [MD]: −5.05 ± 4.25 dB), 13 patients with mild dementia (MD: −9.03 ± 6.66 dB), and 32 healthy controls (MD: −2.50 ± 2.12 dB). OCT was performed on both eyes of each subject. The diagnostic sensitivity in identifying individuals with cognitive impairment of the Spectralis OCT parameters—such as those of the optic nerve head and macula—was compared across these groups. The area under the receiver operating characteristic curve (AUC) for each parameter was calculated to assess its sensitivity in differentiating between healthy eyes and those of individuals with MCI or mild dementia. Results: Among the parameters evaluated, the Bruch’s membrane opening minimum rim width (BMO-MRW) nasal inferior region (ACU = 0.720) was the optimal parameter for distinguishing individuals with MCI from healthy controls. However, the highest AUC of 0.861 was achieved through a combination of five parameters. In distinguishing individuals with mild dementia from healthy controls, the BMO-MRW temporal superior region (ACU = 0.764) was the optimal parameter, with an AUC of 0.940 after adjusting for age and MD. Moreover, the condition of the macular nerve fiber layer outer inferior parameter moderately predicted disease progression (AUC = 0.713). Conclusions: Our preliminary data demonstrate that Spectralis OCT shows potential in detecting MCI and mild dementia as well as for assessing disease progression in a Taiwanese population. Additional large-scale longitudinal and multiracial studies are essential to validate these findings. Full article

Background: The implantable miniature telescope is used to provide functional vision for patients with advanced AMD. However, despite the considerable cost of the device, there are strict criteria to be met for this procedure, since the patients require challenging neuroadaptation afterward, which sometimes fails and leads to the necessity of device explantation. Visual outcomes also depend on the stability of the microtelescope; tilts cause unwanted optical aberrations and can lead to device luxation, with sight-threatening complications. Case report: This case presents a novel technique for fixing the ophthalmic telescope device SING-IMT™. A 76-year-old female with pre-operative visual acuity of 15 letters on the ETDRS scale underwent surgery on her left eye. The superior haptic was fixed at the 12 o’clock position with a Prolene 5-0 suture, achieving good postoperative stability. The implant was stable throughout the entire observation period. Conclusions: Implant stability is crucial for maximizing visual potential in patients with advanced AMD selected for the procedure, since visual acuity in the peripheral retina, where the perceived image eventually lands, is much lower than the macula. Therefore, there is a need to standardize surgical approaches and use objective follow-up measures to assess long-term patient satisfaction. Full article

Background and Objectives: To evaluate the occurrence of retinal displacement using blue-fundus autofluorescence (BFAF) imaging in eyes treated for primary rhegmatogenous retinal detachment (RRD) and its associations with clinical factors, including macular status, detachment extent, baseline visual acuity, high myopia, postoperative visual recovery, and metamorphopsia. Materials and Methods: This retrospective observational study included 98 patients who underwent surgery for primary RRD at a single center. Surgical approaches included pars plana vitrectomy (PPV), phacovitrectomy, or scleral buckling, with tamponade agents such as SF₆ gas (20%), silicone oil (≈1300 cSt), or air. Postoperative BFAF imaging assessed retinal displacement. Demographic and clinical data were recorded. Results: Macula-off detachments occurred in 56.1% of cases, while 43.9% were macula-on detachments. Phacovitrectomy was performed in 41.8%, simple vitrectomy in 33.7%, and scleral buckling in 24.5%. SF₆ gas was the most used tamponade, while silicone oil was used in 13.3%. Retinal displacement was detected in 16.3% of cases, predominantly downward (81.25%) and less commonly upward (18.75%). Macula-off detachments were significantly associated with displacement (81.2% vs. 51.2%, p = 0.027). No significant associations were found with other parameters. Metamorphopsia was reported in 12.5% of patients with displacement and 4.9% without, though the difference was not statistically significant. Conclusions: Retinal displacement can occur after primary RRD repair, irrespective of tamponade, though it tended to be less frequent with silicone oil and in macula-on detachments. It is significantly more common in macula-off cases, even with immediate postoperative prone positioning. These findings emphasize the need to refine postoperative positioning protocols to reduce displacement and its sequelae. Further studies should explore the impact of retinal displacement on visual function, particularly metamorphopsia, in patients with preserved best-corrected visual acuity. Full article

Carotenoids accumulate in both the skin and the macula, but their biochemical specificity, anatomical localization, optical environments, and temporal kinetics differ fundamentally. Despite superficial similarities, these distinctions raise questions about whether non-invasive skin carotenoid measurements, which are obtained using reflection spectroscopy or resonance Raman spectroscopy, can meaningfully reflect macular pigment optical density (MPOD), a retina-specific biomarker associated with visual performance and neuroprotective function. This review synthesizes evidence across biochemistry, tissue distribution, optical pathways, kinetic behavior, and statistical correlations to evaluate this proposed relationship. Skin carotenoid measurements capture a broad mixture of dietary carotenoids, which are dominated by β-carotene and lycopene, that accumulate superficially within the epidermis and dermis and respond rapidly to short-term dietary and environmental changes. In contrast, MPOD reflects only lutein, zeaxanthin, and meso-zeaxanthin, which are selectively transported into the foveal neurosensory retina and change slowly through regulated retinal uptake and deposition. Across human studies, correlations between skin carotenoids and MPOD are weak, inconsistent, and biologically implausible, with large cohort analyses demonstrating near-zero associations. Collectively, evidence across biochemical, anatomical, optical, physiological, and statistical domains shows that skin carotenoid values encode general systemic antioxidant exposure, whereas MPOD reflects a highly localized, retina-specific carotenoid reservoir. Therefore, skin carotenoid measurements cannot be used to estimate, substitute for, or infer macular pigment levels. Accurate assessment of MPOD requires direct retinal imaging technologies. Full article

Background/Objectives: Optical coherence tomography angiography (OCTA) is a non-invasive imaging method that enables accurate in vivo visualisation and quantification of the macular and optic nerve head microvasculature, providing an indirect assessment of local retinal perfusion. This study aimed to evaluate the changes in OCTA perfusion parameters of macula and optic nerve head in healthy individuals following different isometric exercises and to determine their association with intraocular pressure alterations. Methods: Each subject performed four isometric exercises: elbow plank, reverse plank, right-side plank, and wall sit. Measurements of intraocular pressure, systemic blood pressure, heart rate, and OCT angiography of macula and optic nerve head were conducted before each exercise, immediately after its completion, and after a five-minute rest period. Intraocular pressure was measured using a Perkins applanation tonometer, and systemic blood pressure and heart rate were recorded using an automated sphygmomanometer. The relationship between changes in intraocular pressure and OCTA perfusion parameters was analysed. Results: A total of 12 eyes of 12 healthy subjects were included in the study, with a mean age of 28.67 ± 2.39 years. An immediate reduction in optic nerve head vessel density was observed after each exercise (elbow plank: p = 0.012; wall sit: p = 0.009; reverse plank: p < 0.001; right-side plank: p < 0.001), with a sustained decrease during the rest period following right-side plank. No significant changes in vessel density were observed in the macular region. Heart rate and systemic blood pressure increased after each exercise, while intraocular pressure increased following all exercises except the wall sit. Changes in intraocular pressure were significantly negatively associated with changes in optic nerve head vessel density in the post-rest period following elbow plank (inside disc sector: b = −1.153, p = 0.02, peripapillary sector: b = −0.369, p = 0.009) and reverse plank (whole image sector: b = −0.589, p = 0.031). Conclusions: The performance of isometric exercises induced an acute reduction in optic nerve head vessel density, and a significant association with intraocular pressure changes was observed. OCTA represents a promising research tool not only for the assessment of retinal microcirculation but also in the field of sports medicine. Full article

Background/Objectives: Clinical differentiation between Parkinson’s disease (PD) and atypical parkinsonism (AP) remains complex. Current diagnostic procedures helpful in their distinction lack specificity, making non-invasive tools like optical coherence tomography (OCT) crucial in evaluating possible retinal changes as potential biomarkers. Our study examined the thickness of the ganglion cell inner plexiform layer complex (GCIPL), peripapillary retinal nerve fiber layer (RNFL) and macular segments in individuals with PD, multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and healthy controls (HC). The objective of our study was to determine if OCT analyses can effectively discriminate PD patients from HC and whether retinal thickness can distinguish typical PD patients from those with AP. Methods: Research was an observational, cross-sectional study. Multiple retinal layers measured with OCT of PD and AP patients were compared with age- and sex-matched HC. An intergroup assessment was conducted. Results: Patients with PD and PSP exhibit a thinner GCIPL compared to HC, with no difference observed in the MSA group. GCIPL thickness between investigational groups does not differentiate between PD and AP. The RNFL and central macula thickness were statistically significantly reduced in all patient groups compared to HC. The RNFL was thinner in PSP compared to PD. Nearly all inner and outer macular segments were thinner in the investigational groups compared to HC. The preservation of outer nasal segments distinguished HC from both typical and AP. Patients with PSP and PD differed in the thickness of all macular segments, being thinner in PSP patients. Conclusions: Thickness of multiple retinal layers and macular regions might serve as a distinguishing feature between PD, AP and HC. Full article

Background/Objectives: The vestibular labyrinth is classically viewed as a sensor of low-frequency head motion—linear acceleration for the otoliths and angular velocity/acceleration for the semicircular canals. However, there is now substantial evidence that air-conducted sound (ACS) can also activate vestibular receptors and afferents in mammals and other vertebrates. This sound sensitivity underlies sound-evoked vestibular-evoked myogenic potentials (VEMPs), sound-induced eye movements, and several clinical phenomena in third-window pathologies. The cellular and biophysical mechanisms by which a pressure wave in the cochlear fluids is transformed into a vestibular neural signal remain incompletely integrated into a single framework. This study aimed to provide a narrative synthesis of how ACS activates the vestibular labyrinth, with emphasis on (1) the anatomical and biophysical specializations of the maculae and cristae, (2) the dual-channel organization of vestibular hair cells and afferents, and (3) the encoding of fast, jerk-rich acoustic transients by irregular, striolar/central afferents. Methods: We integrate experimental evidence from single-unit recordings in animals, in vitro hair cell and calyx physiology, anatomical studies of macular structure, and human clinical data on sound-evoked VEMPs and sound-induced eye movements. Key concepts from vestibular cellular neurophysiology and from the physics of sinusoidal motion (displacement, velocity, acceleration, jerk) are combined into a unified interpretative scheme. Results: ACS transmitted through the middle ear generates pressure waves in the perilymph and endolymph not only in the cochlea but also in vestibular compartments. These waves produce local fluid particle motions and pressure gradients that can deflect hair bundles in selected regions of the otolith maculae and canal cristae. Irregular afferents innervating type I hair cells in the striola (maculae) and central zones (cristae) exhibit phase locking to ACS up to at least 1–2 kHz, with much lower thresholds than regular afferents. Cellular and synaptic specializations—transducer adaptation, low-voltage-activated K⁺ conductances (K_LV), fast quantal and non-quantal transmission, and afferent spike-generator properties—implement effective high-pass filtering and phase lead, making these pathways particularly sensitive to rapid changes in acceleration, i.e., mechanical jerk, rather than to slowly varying displacement or acceleration. Clinically, short-rise-time ACS stimuli (clicks and brief tone bursts) elicit robust cervical and ocular VEMPs with clear thresholds and input–output relationships, reflecting the recruitment of these jerk-sensitive utricular and saccular pathways. Sound-induced eye movements and nystagmus in third-window syndromes similarly reflect abnormally enhanced access of ACS-generated pressure waves to canal and otolith receptors. Conclusions: The vestibular labyrinth does not merely “tolerate” air-conducted sound as a spill-over from cochlear mechanics; it contains a dedicated high-frequency, transient-sensitive channel—dominated by type I hair cells and irregular afferents—that is well suited to encoding jerk-rich acoustic events. We propose that ACS-evoked vestibular responses, including VEMPs, are best interpreted within a dual-channel framework in which (1) regular, extrastriolar/peripheral pathways encode sustained head motion and low-frequency acceleration, while (2) irregular, striolar/central pathways encode fast, sound-driven transients distinguished by high jerk, steep onset, and precise spike timing. Full article

The purpose of this research is to determine whether retinal vasculatures differ between participants with schizophrenia spectrum disorder (SSD) and controls. Ninety participants (51 SSD, mean age 35.8 ± 13.5, and 39 controls, mean age 35.5 ± 11.4) underwent 3 × 3 mm² macular and 6 × 6 mm² optic nerve head (ONH) optical coherence tomography angiography (OCTA) scans. En face macula and ONH region images were divided into quadrants, binarized, and then skeletonized. Skeletonized vessel densities were compared between our two groups. Additionally, the foveal avascular zone (FAZ) size and acircularity index were compared between the two groups. There was significantly decreased vessel density in the temporal region of the ONH in the SSD group compared to controls (p = 0.033). Interestingly, the decreased vessel density was already present in patients with SSD in younger adulthood as compared to the controls (p = 0.006). There were no significant group differences in vessel density in any other region of the ONH, the ONH overall, any region of the macula, or the macula overall. There were also no significant group differences in the FAZ size or acircularity index. These data suggest there may be abnormal peripapillary retinal vasculature in patients with SSD. Whether this is a specific ocular vascular deficit or related to more systemic vascular abnormalities in SSD remains to be determined. Full article

Since the 1960s, Grassy Narrows First Nation, Canada, has been exposed to methylmercury (MeHg) from fish consumption following Hg discharge from a chloralkali plant. Prenatal exposure to MeHg is known to affect the neurodevelopment of fetuses and the retina is sensitive to neurodevelopmental damage. The multidisciplinary, cross-sectional Niibin study, developed with Grassy Narrows First Nations, included visual examinations with retinal evaluation using optical coherence tomography (OCT). The present analyses focused on the 59 participants (116 eyes) with umbilical cord Hg measurements, sampled between 1971 and 1992. Associations between cord blood Hg and retinal thickness layers surrounding the optic nerve head (RNFL) and inner macula (GC-IPL) were examined using mixed-effect models. Higher cord blood Hg was significantly associated with reduced thickness of GC-IPL layers across all macular sectors; less pronounced associations were observed for RNFL. A qualitative clinical assessment of the OCT results showed that persons with cord blood Hg concentrations ≥ 5.8 µg/L were more likely to present bilateral abnormal retinal thinning (OR = 3.51; [95% CI: 1.06–11.53]). These findings suggest that, in this Indigenous community, prenatal MeHg exposure may have enduring effects on retinal thickness and underline the importance of OCT technology in providing tailored eye care. Full article

Objectives: To evaluate the utility of widefield montage swept-source OCT angiography (SS-OCTA) in detecting and monitoring retinal vasculitis beyond the posterior pole. Methods: Prospective case series. Patients with clinically diagnosed retinal vasculitis imaged with a same-day widefield SS-OCTA montage and ultra-widefield fluorescein angiography (FA) at 2 or more visits. Five overlapping 12 × 12 mm SS-OCTA scans were acquired to provide imaging of the posterior pole and each quadrant of the near periphery. A color retinal thickness map was superimposed on each 12 × 12 mm en-face flow scan with a customized segmentation to demonstrate perivascular retinal thickening. A composite “montage” image was then created by combining the scans to allow for analysis of the macula and near periphery. Findings were then correlated with the same-day FA, the current “gold standard” diagnostic tool for retinal vasculitis, to assess diagnostic efficacy. Results: SS-OCTA demonstrated perivascular thickening in both the posterior pole and peripheral retina in 30 eyes of 16 patients and was found to be an effective diagnostic tool with good correlation to findings on fluorescein angiography for monitoring retinal vasculitis over time. Conclusions: The widefield SS-OCTA montage expands the visualization of retinal vasculitis into the near periphery, providing a noninvasive tool that may complement FA in the diagnosis and monitoring of retinal vasculitis. Full article

Background/Objectives: Oxidative stress plays a significant role in the development and progression of age-related macular degeneration (AMD). Retinal pigment epithelium (RPE) cells are specialized multifunctional cells indispensable for the maintenance of vision. The dysfunction and death of RPE cells in the macula characterize the onset and development of AMD. Of the various toxic agents that impact the health of the RPE, particular focus has been given to various forms of lipoproteins and their cytotoxic derivatives normally present in the retina. Oxidized low-density lipoprotein (OxLDL), derived from LDL in a pro-oxidative environment, is found adjacent to RPE cells as part of drusen, extracellular deposits that are a hallmark feature of AMD. OxLDL is a potent inflammatory agent and it has been implicated in cardiovascular and neurodegenerative conditions. The cellular molecular mechanisms triggered by OxLDL are only partially understood. The focus of this study was to characterize changes in the proteome of RPE cells after exposure to OxLDL, with a focus on the characterization and quantification of ubiquitinated proteins. Methods: Identification and quantification were performed with a high-resolution LC-MS/MS-based proteomics workflow after immune-enrichment for ubiquitinated peptides. Results: In total, out of the more than 1000 RPE ubiquitinated peptides quantified, OxLDL treatment caused a significant increase in ubiquitinated peptides compared to LDL and untreated cells. Principal component analysis (PCA) of the differentially ubiquitinated proteins (265) reduced the data complexity in two main groups of variables (proteins). Conclusions: Gene ontology enrichment analysis of the grouped proteins with the highest loading contribution to principal component 1 (PC1) and principal component 2 (PC2) revealed significant ubiquitination changes upon OxLDL treatment in proteins of the ubiquitin–proteasome system (UPS) responsible for proteasome-mediated catabolic processes and in protein members of the cellular translation machinery. Full article

Background: Trabeculectomy remains gold-standard surgical approach for intraocular pressure (IOP) control in glaucoma, yet its impact on optic nerve head (ONH) morphology and retinal microvasculature has not been fully clarified. This study aimed to investigate structural and vascular changes of the ONH and macula after trabeculectomy using spectral-domain optical coherence tomography (SD-OCT) and OCT angiography (OCTA). Methods: In this retrospective study, data from 22 patients with primary open-angle glaucoma who underwent uncomplicated trabeculectomy were reviewed. The fellow eye served as control. Structural parameters, including Bruch’s membrane opening (BMO), maximum cup depth (MCD), and cup area, were measured with SD-OCT. Vessel density (VD) of the optic disc, peripapillary retina, and macular superficial (SCP) and deep (DCP) capillary plexuses were analyzed with OCTA. Preoperative and two-month postoperative data were compared using paired statistical tests. Results: Mean IOP decreased from 23.1 ± 3.9 mmHg to 13.2 ± 3.2 mmHg (p < 0.001). Significant postoperative reductions were observed in BMO (−5 ± 6%, p = 0.004), MCD (−31 ± 8%, p < 0.001), and cup area (−44 ± 18%, p < 0.001). RNFL thickness and ONH vascular parameters remained stable. In contrast, DCP vessel density increased in the foveal (p = 0.002) and parafoveal (p = 0.023) regions, while SCP density showed no significant change. Conclusions: Trabeculectomy was associated with measurable reversal of optic disc cupping, indicating partial structural recovery of the ONH following IOP reduction. The selective improvement in deep retinal vessel density suggests a layer-specific microvascular response. These findings provide further insight into the interplay between mechanical and vascular mechanisms in glaucoma and may inform postoperative monitoring strategies. Full article

Purpose: The aim was to compare the short-term outcomes of aflibercept 8 mg and brolucizumab for the treatment of polypoidal choroidal vasculopathy (PCV). Methods: This study included 48 eyes of 48 patients with PCV. Drug selection was based on the treatment period. Sixteen eyes received aflibercept 8 mg and thirty-two eyes received brolucizumab. All eyes underwent three consecutive monthly injections: aflibercept (114.3 mg/mL; 0.07 mL) or brolucizumab (120 mg/mL; 0.05 mL). Indocyanine green angiography was performed at baseline and at the 3-month visit to confirm the presence of polypoidal lesions. Results: In the aflibercept 8 mg group, best-corrected visual acuity (BCVA) significantly improved from 0.28 ± 0.26 at baseline to 0.18 ± 0.25 at the 3-month visit (p < 0.001). In the brolucizumab 6 mg group, BCVA improved from 0.35 ± 0.26 to 0.29 ± 0.27, although the change was not statistically significant (p = 0.08). Multivariate regression analysis showed that better BCVA at 3 months was associated with better baseline BCVA and lower central retinal thickness (CRT), independent of the drug used. CRT decreased from 382 ± 157 to 198 ± 98 in the brolucizumab 6 mg group and from 358 ± 152 to 192 ± 76 in the aflibercept 8 mg group at 3 months. Subfoveal choroidal thickness (SCT) decreased from 201 ± 78 to 167 ± 60 in the brolucizumab 6 mg group and from 186 ± 76 to 153 ± 67 in the aflibercept 8 mg group. The dry macula rate at 3 months was the same for aflibercept 8 mg and brolucizumab 6 mg at 93.8%. Complete regression of polypoidal lesions was observed in 62.5% and 75.0% of patients in the aflibercept and brolucizumab groups, respectively (p = 0.57). Conclusions: During the induction phase, aflibercept 8 mg demonstrated comparable outcomes to brolucizumab 6 mg in reducing CRT and SCT, achieving a dry macula, improving BCVA, and regressing polypoidal lesions in eyes with PCV. Full article