What does visual snow look like? Quantification by matching a simulation.

The primary symptom of visual snow syndrome (VSS) is the unremitting perception of small, flickering dots covering the visual field. VSS is a serious but poorly understood condition that can interfere with daily tasks. Several studies have provided qualitative data about the appearance of visual snow, but methods to quantify the symptom are lacking. Here, we developed a task in which participants with VSS adjusted parameters of simulated visual snow on a computer monitor until the simulation matched their internal visual snow. On each trial, participants (n = 31 with VSS) modified the size, density, update speed, and contrast of the simulation. Participants' settings were highly reliable across trials (intraclass correlation coefficients > 0.89), and they reported that the task was effective at stimulating their visual snow. On average, visual snow was very small (less than 2 arcmin in diameter), updated quickly (mean temporal frequency = 18.2 Hz), had low density (mean snow elements vs. background = 2.87%), and had low contrast (average root mean square contrast = 2.56%). Our task provided a quantitative assessment of visual snow percepts, which may help individuals with VSS communicate their experience to others, facilitate assessment of treatment efficacy, and further our understanding of the trajectory of symptoms, as well as the neural origins of VSS.

Effect of the chromaticity of stimuli on night vision disturbances.

The perception of halos and other night vision disturbances is a common complaint in clinical practice. Such visual disturbances must be assessed in order to fully characterize each patient's visual performance, which is particularly relevant when carrying out a range of daily tasks. Visual problems are usually assessed using achromatic stimuli, yet the stimuli encountered in daily life have very different chromaticities. Hence, it is important to assess the effect of the chromaticity of visual stimuli on night vision disturbances. The aim of this work is to study the influence of the chromaticity of different visual stimuli on night vision disturbances by analyzing straylight and visual discrimination under low-light conditions. For that, we assessed the monocular and binocular visual discrimination of 27 subjects under low illumination using the Halo test. The subjects' visual discrimination was assessed after exposure to different visual stimuli: achromatic, red, green, and blue, both at the monitor's maximum luminance and maintaining the same luminance value for the different visual stimuli. Monocular straylight was also measured for an achromatic, red, green, and blue stimuli. The blue stimulus had the greatest effect on halos in both monocular and binocular conditions. Visual discrimination was similar for the red, green, and achromatic stimuli, but worsened at lower luminance. The greatest influence of straylight was observed for the blue stimulus. In addition, visual discrimination correlated with straylight measurements for achromatic stimuli, wherein greater straylight values correlated with an increased perception of halos and other visual disturbances.

Light Scattering by Vitreous of Humans With Vision Degrading Myodesopsia From Floaters.

Purpose: Vision-degrading myodesopsia (VDM) from vitreous floaters significantly degrades vision and impacts visual quality of life (VQOL), but the relationship to light scattering is poorly understood. This study compared in vitro measures of light scatter and transmission in surgically excised human vitreous to preoperative indexes of vitreous structure, visual function, and VQOL. Methods: Pure vitreous collected during vitrectomy from 8 patients with VDM had wide-angle straylight measurements and dark-field imaging, performed within 36 hours of vitrectomy. Preoperative VQOL assessment with VFQ-25, contrast sensitivity (CS) measurements with Freiburg acuity contrast testing, and quantitative ultrasonography were compared to light scattering and transmission in vitro. Results: All indices of vitreous echodensity in vivo correlated positively with straylight at 0.5° (R = 0.708 to 0.775, P = 0.049 and 0.024, respectively). Straylight mean scatter index correlated with echodensity (R = 0.71, P = 0.04) and VQOL (R = -0.82, P = 0.0075). Dark-field measures in vitro correlated with degraded CS in vivo (R = -0.69, P = 0.04). VQOL correlated with straylight mean scatter index (R = -0.823, P = 0.012). Conclusions: Increased vitreous echodensity in vivo is associated with more straylight scattering in vitro, validating ultrasonography as a clinical surrogate for light scattering. Contrast sensitivity in vivo is more degraded in the presence of dark-field scattering in vitro and VQOL is decreased in patients whose vitreous has increased light scattering. These findings could form the basis for the development of optical corrections for VDM or support new laser treatments, as well as novel pharmacotherapy.

Cerebral versus cortical visual impairment: eliminating the conflict and renewing the terminology.

The inconsistency in terminology for Cortical Visual Impairment or Cerebral Visual Impairment presents challenges: (1) different levels of changes in visual pathway and other cerebral areas do not allow discrimination; (2) different visual and oculomotor aspects are not adequately considered. We open a debate to consider a more appropriate diagnosis.

Improving Understanding of Visual Snow by Quantifying its Appearance and Effect on Vision.

Purpose: Visual snow is the hallmark of the neurological condition visual snow syndrome (VSS) but the characteristics of the visual snow percept remain poorly defined. This study aimed to quantify its appearance, interobserver variability, and effect on measured visual performance and self-reported visual quality. Methods: Twenty-three participants with VSS estimated their visual snow dot size, separation, luminance, and flicker rate by matching to a simulation. To assess whether visual snow masks vision, we compared pattern discrimination thresholds for textures that were similar in spatial scale to visual snow as well as more coarse than visual snow, in participants with VSS, and with and without external noise simulating visual snow in 23 controls. Results: Mean and 95% confidence intervals for visual snow appearance were: size (6.0, 5.8-6.3 arcseconds), separation (2.0, 1.7-2.3 arcmin), luminance (72.4, 58.1-86.8 cd/m2), and flicker rate (25.8, 18.9-32.8 frames per image at 120 hertz [Hz]). Participants with finer dot spacing estimates also reported greater visibility of their visual snow (τb = -0.41, 95% confidence interval [CI] = -0.62 to -0.13, P = 0.01). In controls, adding simulated fine-scale visual snow to textures increased thresholds for fine but not coarse textures (F(1, 22) = 4.98, P = 0.036, ηp2 = 0.19). In VSS, thresholds for fine and coarse textures were similar (t(22) = 0.54, P = 0.60), suggesting that inherent visual snow does not act like external noise in controls. Conclusions: Our quantitative estimates of visual snow constrain its likely neural origins, may aid differential diagnosis, and inform future investigations of how it affects vision. Methods to quantify visual snow are needed for evaluation of potential treatments.

Visuospatial processing in early brain-based visual impairment is associated with differential recruitment of dorsal and ventral visual streams.

Visuospatial processing impairments are prevalent in individuals with cerebral visual impairment (CVI) and are typically ascribed to "dorsal stream dysfunction" (DSD). However, the contribution of other cortical regions, including early visual cortex (EVC), frontal cortex, or the ventral visual stream, to such impairments remains unknown. Thus, here, we examined fMRI activity in these regions, while individuals with CVI (and neurotypicals) performed a visual search task within a dynamic naturalistic scene. First, behavioral performance was measured with eye tracking. Participants were instructed to search and follow a walking human target. CVI participants took significantly longer to find the target, and their eye gaze patterns were less accurate and less precise. Second, we used the same task in the MRI scanner. Along the dorsal stream, activation was reduced in CVI participants, consistent with the proposed DSD in CVI. Intriguingly, however, visual areas along the ventral stream showed the complete opposite pattern, with greater activation in CVI participants. In contrast, we found no differences in either EVC or frontal cortex between groups. These results suggest that the impaired visuospatial processing abilities in CVI are associated with differential recruitment of the dorsal and ventral visual streams, likely resulting from impaired selective attention.

Evaluation of 3D tablet-based stereoacuity test ASTEROID in children with normal and abnormal visual acuity.

PURPOSE: To assess the utility of 3D, tablet-based, glasses-free Accurate STEReotest (ASTEROID) in children compared with the Titmus test. METHODS: Children aged 5-13 years were enrolled in a single-center, nonrandomized, observational comparison study and analyzed by age (5-7 vs 8-13 years) and visual acuity (20/25 or better in both eyes vs abnormal). Each participant underwent both the ASTEROID and Titmus stereoacuity tests. Stereoacuity was defined as fine (≤60 arcsec), moderate (61-200 arcsec), coarse (201-1199 arcsec), or very coarse to nil (≥1200 arcsec). Agreement between the tests was assessed using a weighted kappa (κ) statistic based on all four categories. RESULTS: A total of 112 children were included: 28 aged 5-7 with normal visual acuity, 30 aged 5-7 with abnormal visual acuity, 34 aged 8-13 with normal visual acuity, and 20 aged 8-13 with abnormal visual acuity. Mean ASTEROID score was 688 ± 533 arcsec (range, 13-1200 arcsec). Agreement between ASTEROID and Titmus test scores for participants overall was moderate (κ = 0.52). By subgroup, agreement was fair for children 5-7 with abnormal visual acuity (κ = 0.31), moderate for children 5-7 with normal visual acuity (κ = 0.47) and children 8-13 with normal visual acuity (κ = 0.42), and substantial for children 8-13 with abnormal visual acuity (κ = 0.76). Where ASTEROID and Titmus score group varied, ASTEROID score was poorer in 94% (47/50) of cases. CONCLUSIONS: ASTEROID is a digital, tablet-based test that evaluates global stereopsis, does not require glasses, and provides a continuum of scores. Among children, ASTEROID has good agreement with the Titmus test; however, it may be more sensitive at detecting stereovision deficits. Further study is necessary to determine which test is more accurate.

Pilot study comparing a new virtual reality-based visual field test to standard perimetry in children.

PURPOSE: To assess the feasibility and performance of Vivid Vision Perimetry (VVP), a new virtual reality (VR)-based visual field platform. METHODS: Children 7-18 years of age with visual acuity of 20/80 or better undergoing Humphrey visual field (HVF) testing were recruited to perform VVP, a VR-based test that uses suprathreshold stimuli to test 54 field locations and calculates a fraction seen score. Pearson correlation coefficients were calculated to evaluate correlation between HVF mean sensitivity and VVP mean fraction seen scores. Participants were surveyed regarding their experience. RESULTS: A total of 37 eyes of 23 participants (average age, 12.9 ± 3.1 years; 48% female) were included. All participants successfully completed VVP testing. Diagnoses included glaucoma (12), glaucoma suspect (7), steroid-induced ocular hypertension (3), and craniopharyngioma (1). Sixteen participants had prior HVF experience, and none had prior VVP experience, although 7 had previously used VR. Of the 23 HVF tests performed, 9 (39%) were unreliable due to fixation losses, false positives, or false negatives. Similarly, 35% of VVP tests were unreliable (as defined by accuracy of blind spot detection). Excluding unreliable HVF tests, the correlation between HVF average mean sensitivity and VVP mean fraction seen score was 0.48 (P = 0.02; 95% CI, 0.09-0.74). When asked about preference for the VVP or HVF examination, all participants favored the VVP, and 70% were "very satisfied" with VVP. CONCLUSIONS: In our cohort of 23 pediatric subjects, VVP proved to be a clinically feasible VR-based visual field testing, which was uniformly preferred over HVF.

Digital therapeutics using virtual reality-based visual perceptual learning for visual field defects in stroke: A double-blind randomized trial.

INTRODUCTION: Visual field defects (VFDs) represent a debilitating poststroke complication, characterized by unseen parts of the visual field. Visual perceptual learning (VPL), involving repetitive visual training in blind visual fields, may effectively restore visual field sensitivity in cortical blindness. This current multicenter, double-blind, randomized, controlled clinical trial investigated the efficacy and safety of VPL-based digital therapeutics (Nunap Vision [NV]) for treating poststroke VFDs. METHODS: Stroke outpatients with VFDs (>6 months after stroke onset) were randomized into NV (defective field training) or Nunap Vision-Control (NV-C, central field training) groups. Both interventions provided visual perceptual training, consisting of orientation, rotation, and depth discrimination, through a virtual reality head-mounted display device 5 days a week for 12 weeks. The two groups received VFD assessments using Humphrey visual field (HVF) tests at baseline and 12-week follow-up. The final analysis included those completed the study (NV, n = 40; NV-C, n = 35). Efficacy measures included improved visual area (sensitivity ≥6 dB) and changes in the HVF scores during the 12-week period. RESULTS: With a high compliance rate, NV and NV-C training improved the visual areas in the defective hemifield (>72 degrees2) and the whole field (>108 degrees2), which are clinically meaningful improvements despite no significant between-group differences. According to within-group analyses, mean total deviation scores in the defective hemifield improved after NV training (p = .03) but not after NV-C training (p = .12). CONCLUSIONS: The current trial suggests that VPL-based digital therapeutics may induce clinically meaningful visual improvements in patients with poststroke VFDs. Yet, between-group differences in therapeutic efficacy were not found as NV-C training exhibited unexpected improvement comparable to NV training, possibly due to learning transfer effects.

Optical and clinical simulated performance of a new refractive extended depth of focus intraocular lens.

OBJECTIVES: The purpose of this study is to evaluate the optical and expected clinical performance of a new refractive Extended Depth of Focus (EDF) intraocular lens (IOL) designed to maintain a monofocal-like dysphotopsia profile. METHODS: Simulated visual acuity (sVA) with varying defocus was calculated using the area under the Modulation Transfer Function measured in an average eye model and from computer simulations in eye models with corneal higher-order aberrations. Tolerance to defocus was evaluated using computer simulations of the uncorrected distance sVA under defocus. To evaluate the dysphotopsia profile, halo pictures obtained using an IOL-telescope, as well as simulated images in a realistic eye model under defocus were assessed. The results of the refractive EDF were compared to those of a diffractive EDF of the same platform. RESULTS: The refractive EDF IOL provides similar range of vision to the diffractive EDF IOL with the same distance, and similar intermediate and near sVA. The refractive EDF IOL provides the same tolerance to hyperopia as the diffractive EDF but more tolerance to myopia. Halo pictures and simulations showed that the refractive EDF provides comparable dysphotopsia profile to the monofocal IOL and better than the diffractive EDF. CONCLUSIONS: The results of this preclinical study in clinically relevant conditions show that the new refractive EDF IOL is expected to provide similar range of vision to the diffractive IOL of the same platform and higher tolerance to refractive errors. The refractive EDF provides a dysphotopsia profile that is better than the diffractive EDF and comparable to that of the monofocal IOL, also in the presence of residual refractive errors.

Yoked prisms and cerebral visual impairment: Enhancing the experience of ambient vision.

BACKGROUND: Perceptual visual impairment leads to impaired functional vision in children with cerebral visual impairment. Yoked prisms have been used in behavioral vision therapy for children with autism (dysfunctional dorsal visual processing pathway) and in neurorehabilitation to treat visual neglect, hemianopia, and abnormal egocentric localization. In particular, they are employed for treating perceptual visual problems. PURPOSE: To share our experience in implementing yoked prisms and their impact on the rehabilitation of children with cerebral visual impairment-related perceptual vision disorders. SYNOPSIS: The first child with periventricular leukomalacia exhibits no eagerness to explore her new environment along with poor grasp. With 4-PD base-down prisms, she explores her surroundings and appreciates her lateral supports. Her grasp improved as well. The second child with cerebral visual impairment exhibits difficulty in climbing downstairs with poor obstacle negotiation. This could be due to impaired inferior field awareness or optic ataxia. With 4-PD base-down prisms, the field shift toward the apex helps him to climb downstairs without difficulty with an improved obstacle negotiation. The third child prefers a closer look at the object of interest along with poor hand-eye coordination. We employed 4-PD base-down prisms in her rehabilitation session. She showed good improvement in her hand-eye coordination. HIGHLIGHTS: Poor hand-eye coordination, difficulty climbing downstairs, optic ataxia, impaired field awareness, and triggering spontaneous exploration in children with perceptual visual problems can be effectively tackled by the simple incorporation of yoked prisms. VIDEO LINK: https://youtu.be/BW3cwiGDTLY.

Digital Technology Use Among Older Adults With Vision Impairment.

Importance: Telehealth has the potential to improve health for older adults, but many access disparities exist, including for those with vision impairment (VI). Objective: To examine the associations between VI and digital technology access measures in US older adults. Design, Setting, and Participants: This was a cross-sectional study that included Medicare beneficiaries 65 years and older. Beneficiary data were obtained from the National Health and Aging Trends Study (NHATS) 2021; data collection was conducted from June 2020 through January 2021. Data were analyzed September 2023. Exposure: VI, measured on categorical (distance and near VI [>0.30 logMAR], contrast sensitivity impairment [CSI; <1.55 logCS], and any VI [distance VI, near VI, or CSI]), and continuous (distance and near acuity [logMAR] and contrast sensitivity [logCS]) scales. Main Outcomes: Self-reported outcomes of digital technology access from the technological environment component of the NHATS. Results: Of the 2822 Medicare beneficiaries (mean [SD] age, 78.5 [5.6] years; 1605 female [54.7%]) included in this study, patients self-identified with the following race and ethnicity categories (weighted percentages): 575 non-Hispanic Black (8.0%), 132 Hispanic (7.0%), 2019 non-Hispanic White (81.7%), and 63 non-Hispanic other race (3.4%), which included American Indian, Alaska Native, Asian, multiracial, Native Hawaiian, Pacific Islander, or other specified race. A total of 1077 of 2822 patients (32.3%) had any VI. In multivariable logistic regression models, older adults with any VI had lower odds of having or knowing how to use a cellphone (odds ratio [OR], 0.58; 95% CI, 0.38-0.88), computer (OR, 0.61; 95% CI, 0.47-0.79), or tablet (OR, 0.68, 95% CI = 0.54-0.85) than peers without VI. In other models, near VI was associated with lower odds of having and knowing how to use a phone (OR, 0.56; 95% CI, 0.36-0.87), computer (OR, 0.57; 95% CI, 0.44-0.75), or tablet (OR, 0.65; 95% CI, 0.52-0.81) compared with no near VI. CSI was associated with lower odds of having and knowing how to use a phone (OR, 0.66; 95% CI, 0.45-0.99) or computer (OR, 0.72; 95% CI, 0.55-0.93) compared with no CSI. Distance VI was only associated with lower odds of having and knowing how to use a cellphone (OR, 0.63; 95% CI, 0.41-0.95). Any VI and individual categorical VI measures were not associated with other outcomes of digital health- and nonhealth-related experiences. Similar associations were noted when vision was examined on a continuous scale. However, worse distance acuity (per 0.1 logMAR) was associated with being less likely to visit with family or friends on a video call (OR, 0.91; 95% CI, 0.84-0.98) and to order or refill prescriptions online (OR, 0.90; 95% CI, 0.83-0.97). Conclusions and Relevance: Results suggest that older US adults with VI were less likely to have access to digital technology than peers without VI, although no differences were noted in the report of digital health- and nonhealth-related activities. These findings highlight the potential for inequities that may arise in telehealth for older adults with VI and the necessity to develop strategies to improve accessibility of telemedicine for all.

Long-term Follow-Up and Regeneration of Retinal Pigment Epithelium (RPE) after Tears of the Epithelium in Exudative Age-Related Macular Degeneration (AMD).

BACKGROUND: The goals of this study are to evaluate potential long-term visual deterioration associated with retinal pigment epithelial (RPE) tears in patients with neovascular age-related macular degeneration (nAMD) and to find treatment-related and morphological factors that might influence the outcomes. PATIENTS AND METHODS: This retrospective study enrolled 21 eyes of 21 patients from the database of Vista Eye Clinic Binningen, Switzerland, diagnosed with RPE tears, as confirmed by spectral domain optical coherence tomography (SD-OCT), with a minimum follow-up period of 12 months. Treatment history before and after RPE rupture with anti-VEGF therapy, visual acuity, and imaging (SD-OCT) were analyzed and statistically evaluated for possible correlations. RESULTS: Mean patient age was 80.5 ± 6.2 years. The mean length of total follow-up was 39.7 ± 13.9 months. The mean pigment epithelial detachment (PED) height increased by 363.8 ± 355.5 µm from the first consultation to 562.8 ± 251.5 µm at the last consultation prior to rupture. Therefore, a higher risk of RPE rupture is implied as a result of an increase in PED height (p = 0.004, n = 14). The mean visual acuity before rupture was 66.2 ± 16.0 letters. Mean visual acuity deteriorated to 60.8 ± 18.6 letters at the first consultation after rupture (p = 0.052, n = 21). A statistically nonsignificant decrease in vision was noted in the follow-up period. After 2 years, the mean BCVA decreased by 10.5 ± 23.7 ETDRS letters (p = 0.23, n = 19). PED characteristics before rupture and amount of anti-VEGF injections after rupture did not affect the visual outcome. None of the 21 patients included in our study showed a visual improvement in the long-term follow-up. RPE atrophy increased significantly from 3.35 ± 2.94 mm2 (baseline) to 6.81 ± 6.25 mm2 over the course of 2 years (p = 0.000 013, n = 20). CONCLUSIONS: The overall mean vision decrease after rupture was without statistical significance. There was no significant change in BCVA at the 2-year follow-up, independent of the amount of anti-VEGF injections provided. In this study, there was a significant increase in RPE defect over a follow-up of 2 years, implying progression of contraction of RPE and/or macular atrophy.

Long-Term Follow-Up of Myopic Glaucoma: Progression Rates and Associated Factors.

PRCIS: In the group of glaucoma patients with myopia, the more severe the degree of myopia, the faster the loss of visual acuity and central visual field defect. DESIGN: Longitudinal observational study. OBJECTIVE: To investigate the progression rate of myopic glaucoma and associated factors by long-term analysis of its clinical course. METHODS: Patients who had had at least 5 years of follow-up and a spherical equivalent of -0.5 diopters or less were included in this study. They were divided into 3 myopia groups according to myopic grade, namely mild myopia (-0.5 to -3.0 diopters), moderate myopia (-3.0 to -6.0 diopters), and high myopia (-6.0 diopters or more), and the clinical course, progression rate, and associated factors were compared among the groups and analyzed. RESULTS: A total of 121 eyes of 121 patients with glaucoma with myopia were included in the study. The average follow-up period was 10.4 ± 2.9 years. In the analysis of progression rate, the change rate of average retinal nerve fiber layer (RNFL) thickness (-0.75 µm/y in mild myopia, -0.82 µm/y in moderate myopia, -0.84 µm/y in high myopia) and the mean deviation change (-0.30 dB/y in mild myopia, -0.37 dB/y in moderate myopia, -0.39 dB/y in high myopia) both tended to be faster as the myopic grade increased. In a Kaplan-Meier survival analysis, the high myopia groups demonstrated a significantly faster VA loss (of more than 3 lines) and a higher incidence of newly developed central visual field defect (CVFD) than did the mild and moderate myopia groups. Longer axial length (odds ratio: 1.72, CI: 1.03-3.07, P = 0.047) and RNFL defect extending to the macula (odds ratio: 4.14, CI: 1.54-12.30, P = 0.007) were significantly associated with newly developed CVFD. CONCLUSIONS: In patients with myopic glaucoma, the higher the degree of myopia, the faster the rate of visual acuity loss and CVFD occurrence. Occurrence of CVFD was associated with longer axial length and widening of RNFLr defect to the macula.

Sudden Vision Loss.

A 37-year-old woman was referred for evaluation of a retinal detachment in her left eye. Posterior examination results demonstrated a retinal detachment in the posterior pole with shifting fluid and no identifiable retinal break, and there was a thickened choroid with a hyporeflective band on ultrasound biomicroscopy. What would you do next?

Atypical Alzheimer's disease: new insights into an overlapping spectrum between the language and visual variants.

Overlap between language and visual variants of atypical Alzheimer's disease (AD) has been reported. However, the extent, frequency of overlap, and its neuroanatomical underpinnings remain unclear. Eighty-two biomarker-confirmed AD patients who presented with either predominant language (n = 34) or visuospatial/perceptual (n = 48) deficits underwent detailed clinical examinations, MRI, and [18F]flortaucipir-PET. Subgroups were defined based on language/visual testing and patterns of volume loss and tau uptake were assessed. 28% of the language group had visual dysfunction (marked in 8%), and 47% of the visual group had language impairment (marked in 26%). Progressive involvement of the parieto-occipital and frontal lobes was noted with greater visual impairment in the language group, and greater left parieto-temporal and frontal involvement with worsening language impairment in the visual group. Only 25% of our cohort showed a pure language or visual presentation, highlighting the high frequency of syndromic overlap in atypical AD and the diagnostic challenge of categorical phenotyping.

Visual snow syndrome: recent advances in understanding the pathophysiology and potential treatment approaches.

PURPOSE OF REVIEW: Visual snow syndrome (VSS) is a disorder characterized by persistent visual disturbances, including the visual snow phenomenon, palinopsia, heightened perception of entoptic phenomena, impaired night vision, and photophobia. The purpose of this review is to provide an update on recent findings over the past 18 months in VSS research and to summarize the current state of treatment approaches. RECENT FINDINGS: Electrophysiological studies have revealed cortical hyperresponsivity in visual brain areas, imaging studies demonstrated microstructural and functional connectivity alterations in multiple cortical and thalamic regions and investigated glutamatergic and serotoninergic neurotransmission. These findings suggest that VSS might be a network disorder.Only few treatment studies are currently available demonstrating limited response to medication and even worsening or triggering of visual symptoms by certain antidepressants. Promising nonpharmacological treatments include mindfulness-based cognitive therapy, the use of chromatic filters, and research on visual noise adaption and neuro-optometric visual rehabilitation therapy (NORT). However, the level of evidence is still low and further research is needed including larger trials and involving objective measures of individual dysfunction. SUMMARY: Although there has been recent progress, we still have not fully understood the nature of VSS. Further research is needed on a clinical and pathophysiological level to successfully treat the condition.

Spaceflight-associated neuro-ocular syndrome: potential etiologies and connections to the glymphatic system.

The etiology of spaceflight-associated neuro-ocular syndrome (SANS) is a developing field of research, with many current hypotheses receiving varying degrees of support. This syndrome affects ∼70% of astronauts both during and after long-duration space missions, resulting in impaired near vision and visual scotomas (blind spots). In this article, three prominent risk factors for SANS including zero gravity conditions, extraterrestrial hypercapnic environments, and individual genetic predisposition are described. These risk factors are then compared and their pathophysiological pathways are divided into five current hypotheses for the development of SANS. Finally, glymphatic system impairment is explored as a potential mutual end point for these pathways in the development of SANS.

Internal Limiting Membrane Peeling and Inverted Flap Technique in Macular Hole: Postoperative Metamorphopsia and Optical Coherence Tomography.

INTRODUCTION: We compared postoperative metamorphopsia and optical coherence tomography (OCT) findings between eyes that underwent internal limiting membrane (ILM) peeling and the inverted flap (IF) technique for macular hole (MH). METHODS: This retrospective analysis included 64 eyes of 64 patients with idiopathic MH whose MH was closed after initial surgery. Thirty-nine patients were treated with pars plana vitrectomy (PPV) with ILM peeling, and 25 patients were treated with PPV with the IF technique. Best corrected visual acuity (BCVA), severity of metamorphopsia, and OCT images were collected before and 3, 6, and 12 months postoperatively. Based on the OCT images, the status of the external limiting membrane (ELM) and ellipsoid zone and the presence of hyperreflective plugs were assessed. RESULTS: At baseline and 3, 6, and 12 months postoperatively, BCVA and severity of metamorphopsia were not significantly different between groups. The status of the ELM was significantly worse in the IF group than in the ILM peeling group at 3 and 6 months postoperatively. Significantly more hyperreflective plugs were observed in the IF group than in the ILM peeling group at 3 and 6 months postoperatively. Stepwise multiregression analysis revealed that hyperreflective plugs were significantly associated with the severity of metamorphopsia at 12 months postoperatively. DISCUSSION/CONCLUSION: The alterations on the OCT were fewer in the ILM peeling group than in the IF group, while no significant differences were observed in postoperative severity of metamorphopsia between groups. Metamorphopsia was worse in eyes with hyperreflective plugs.

Mesopic pupil indices as potential risk factors for glare disability after intraocular implantable collamer lens implantation: prospective study.

PURPOSE: To explore the influence of preoperative factors, including varying pupil sizes and refractive attributes, on postoperative glare disability in patients undergoing implantable collamer lens (ICL) implantation. SETTING: Second Affiliated Hospital, Nanchang University, Nanchang, Jiangxi, China. DESIGN: Prospective observational study. METHODS: The preoperative ocular characteristics and 6-month postoperative glare status in eligible patients who underwent EVO-Visian ICL V4c (VICMO) implantation were analyzed. The glare disability criteria encompassed a glare symptom score >6 and glare sensitivity exceeding 1:2.7. Logistic regression analysis was used to explore the relationship between the preoperative ocular parameters and post-ICL glare. RESULTS: The study included 95 patients (mean age, 26.04 ± 6.29 years), comprising 30 men (58 eyes) and 65 women (129 eyes). Multivariate analysis revealed a significant correlation between postoperative glare disability and increased spherical power in preoperative mesopic pupils (ß = -0.124, P = .039), as well as elevated cylinder power in preoperative mesopic (ß = -0.412, P = .009) and photopic pupils (ß = -0.430, P = .007). Moreover, a larger preoperative mesopic pupil diameter (ß = 0.561, P = .005) demonstrated a significant correlation with glare disability. CONCLUSIONS: Preoperative mesopic pupil dimensions and associated refractive parameters, such as sphere and cylinder, were correlated with glare disability, including the cylinder aspect in photopic pupils, which can assist clinicians in optimizing preoperative selection for ICL implantation, aiding in the anticipation of potential glare disability risks.