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.

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.

[Perioperative visual loss : Rare, unknown, relevant?] / Perioperativer Visusverlust : Selten, unbekannt, relevant?

Perioperative visual loss (POVL) is a rare but severe complication following non-ophthalmological surgery under general anesthesia. A POVL can be caused by lesions in any part of the optical system. The predominant causes include corneal injuries and particularly ischemic damage. The symptoms of POVL substantially vary ranging from reduced vision to complete blindness. The risks involve factors related to the surgery as well as patient-specific factors. In general, the prognosis in cases of mechanical damage is better than for ischemic lesions. The treatment measures depend on the underlying pathomechanism and due to the limited evidence only a few treatment options are available. Therefore, preventive measures and meticulous documentation play a crucial role.

Development and evaluation of Order of Magnitude (OM): a virtual reality-based visual field analyzer for glaucoma detection.

PURPOSE: This study introduces the Order of Magnitude (OM), a cost-effective, indigenous, virtual reality-based visual field analyzer designed for detecting glaucomatous visual field loss. METHODS: The OM test employs a two-step supra-thresholding algorithm utilizing stimuli of 0.43°diameter (equivalent to Goldmann size III) at low and high thresholds. A comparative analysis was conducted against the Humphrey visual field (HVF) test, considered the gold standard in clinical practice. Participants, including those with glaucoma and normal individuals, underwent comprehensive eye examinations alongside the OM and HVF tests between April and October 2019. Diagnostic sensitivity and specificity of the OM test were assessed against clinical diagnoses made by specialists. RESULTS: We studied 157 eyes (74 glaucomatous, 83 control) of 152 participants. Results demonstrated a high level of reliability for both OM and HVF tests, with no significant difference observed (P = 0.19, Chi-square test). The sensitivity and specificity of the OM test were found to be 93% (95% CI 86-100%) and 83% (95% CI 72.4-93%), respectively, while the HVF test showed sensitivity and specificity of 98% (95% CI 93.9-100%) and 83% (95% CI 73.9-92.8%), respectively. CONCLUSION: These findings suggest that the OM test is non-inferior to the reference standard HVF test in identifying glaucomatous visual field loss.

Clinical, electrophysiologic and serologic evidence of cancer associated retinopathy preceding a diagnosis of breast cancer.

We report the case of a woman in her 50s who presented headaches, blurred vision, diplopia and loss of peripheral vision. She was treated for normal tension glaucoma based on optic nerve cupping prior to the development of diplopia. Records demonstrated visual field constriction over 4 months despite well-controlled intraocular pressures. Examination revealed decreased visual acuity and visual field constriction. The multifocal electroretinogram was abnormal. After a thorough review of her medical and family history, a concern for cancer-associated retinopathy developed. Blood samples were positive for antiretinal antibodies against 23 kDA and 46 kDA proteins. Cancer screening was recommended as the aetiology for retinopathy was unknown and revealed a left breast lump. Following lumpectomy with adjuvant chemoradiation, her visual acuity normalised and visual field defects completely resolved. This case serves to provide an example that distant systemic symptoms may be a manifestation of the underlying malignancy and the importance of clinical suspicion with prompt evaluation.

Evaluation of the SCAT 5 tool in the assessment of concussion in Para athletes: a Delphi study.

OBJECTIVES: To investigate if the sport concussion assessment tool version 5 (SCAT5) could be suitable for application to Para athletes with a visual impairment, a spinal cord injury, or a limb deficiency. METHODS: A 16-member expert panel performed a Delphi technique protocol. The first round encompassed an open-ended questionnaire, with round 2 onwards being composed of a series of closed-ended statements requiring each expert's opinion using a five-point Likert scale. A predetermined threshold of 66% was used to decide whether agreement had been reached by the panel. RESULTS: The Delphi study resulted in a four-round process. After round 1, 92 initial statements were constructed with 91 statements obtaining the targeted level of agreement by round 4. The expert panellist completion rate of the full four-round process was 94%. In the case of athletes with a suspected concussion with either limb deficiencies or spinal cord injuries, the panel agreed that a baseline assessment would be needed on record is ideal before a modified SCAT5 assessment. With respect to visual impairments, it was conceded that some tests were either difficult, infeasible or should be omitted entirely depending on the type of visual impairment. CONCLUSION: It is proposed that the SCAT5 could be conducted on athletes with limb deficiencies or spinal cord injuries with some minor modifications and by establishing a baseline assessment to form a comparison. However, it cannot be recommended for athletes with visual impairment in its current form. Further research is needed to determine how potential concussions could be more effectively evaluated in athletes with different impairments.

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.

Understanding and identifying visual field progression.

Detecting deterioration of visual field sensitivity measurements is important for the diagnosis and management of glaucoma. This review surveys the current methods for assessing progression that are implemented in clinical devices, which have been used in clinical trials, alongside more recent advances proposed in the literature. Advice is also offered to clinicians on what they can do to improve the collection of perimetric data to help analytical progression methods more accurately predict change. This advice includes a discussion of how frequently visual field testing should be undertaken, with a view towards future developments, such as digital healthcare outside the standard clinical setting and more personalised approaches to perimetry.

Saccadic movements during an exploratory visual search task in patients with glaucomatous visual field loss.

PURPOSE: To evaluate the saccadic movements of patients with visual field loss due to primary open-angle glaucoma. METHODS: Thirteen patients with good visual acuity (0.2 logMAR or better) (seven patients with primary open-angle glaucoma 65 ± 13 years) and six controls (51 ± 6 years) yielded a comprehensive ophthalmological examination, including Humphrey Visual Field tests (SITA-Standard 24-2), and performed a monocular, exploratory digital visual search task that quantifies the duration for finding the number "4" on a random array of digits distributed on the screen. After individual adjustments of the angle and distance positioning, the screen was spatially matched with the 24-2 visual field, and divided into five areas for analysis. During the task, saccades were simultaneously recorded in the same eye with a video-based eye tracker. RESULTS: The patients with primary open-angle glaucoma showed a significantly higher number of saccades/screen (median ± interquartile range, 59.00 ± 29.00 vs. 32.50 ± 19.75 saccades (p=0.027) and visual search time per screen (38.50 ± 60.14 vs. 23.75 ± 8.90 seconds (p=0.035) than the controls did. Although the univariate analysis indicated a significant correlation with visual field mean deviation (coefficient=26.19 (p=0.02), only the visual search time/screen was significantly associated with the number of saccades/screen in the multivariate regression model (coefficient=0.55 (p<0.001). Overall, no significant correlation was observed between the sectorial number of saccades and the sensitivity of the five visual field areas. CONCLUSIONS: The patients with primary open-angle glaucoma show impaired search performance and showed a higher number of saccades needed to find stimuli when performing the exploratory visual task.

Delayed-Onset Idiopathic Intracranial Hypertension After Liposuction: A Case Report and Review.

ABSTRACT: Although systemic complications following liposuction are rare, visual impairment has been reported in a few cases and may occur for a variety of reasons. Here we present the case of a 31-year-old woman who underwent 360° liposuction and subsequently developed headaches and delayed partial visual disturbance 10 days after the procedure. She had symptoms suggestive of idiopathic intracranial hypertension, which was confirmed by lumbar puncture. A literature search revealed other case reports of visual changes or headaches following high-volume liposuction. Our case provides further evidence of a rare association between liposuction and idiopathic intracranial hypertension, emphasizing the need for thorough preoperative evaluations and the consideration of possible risks.

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?

Cerebral visual impairment: genetic diagnoses and phenotypic associations.

BACKGROUND: Cerebral visual impairment (CVI) is the most common form of paediatric visual impairment in developed countries. CVI can arise from a host of genetic or acquired causes, but there has been limited research to date on CVI in the context of genetic disorders. METHODS: We carried out a retrospective analysis of genotypic and phenotypic data for participants with CVI within the DECIPHER database and 100 000 Genomes Project (100KGP). RESULTS: 158 individuals with CVI were identified across both cohorts. Within this group, pathogenic or likely pathogenic sequence variants in 173 genes were identified. 25 of these genes already have known associations with CVI, while the remaining 148 are candidate genes for this phenotype. Gene ontology analysis of the CVI gene sets from both DECIPHER and 100KGP suggests that CVI has a similar degree of genetic heterogeneity to other neurodevelopmental phenotypes, and a strong association with genetic variants converging on ion channels and receptor functions. Individuals with a monogenic disorder and CVI have a higher frequency of epilepsies and severe neurodisability than individuals with a monogenic disorder but not CVI. CONCLUSION: This study supports the availability of genetic testing for individuals with CVI alongside other neurodevelopmental difficulties. It also supports the availability of ophthalmological screening for individuals with genetic diagnoses linked to CVI. Further studies could elaborate on the links between specific genetic disorders, visual maturation and broader neurodevelopmental characteristics.

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.

The visual field-testing maze and vision maze: Feasible techniques to evaluate visual field loss in animals.

Visual field loss due to glaucoma is a severe and concerning problem, leading to limited visual range and poor quality vision. The progression of this loss begins with a para-central arcuate scotoma which eventually advances to a ring scotoma and constricted visual fields in later stages. Currently, no animal model is available for screening this pattern of vision loss. However, we have successfully developed two mazes to evaluate visual field loss - the visual field-testing maze (VFTZ) for peripheral vision loss and the vision maze (VM) for central vision loss. Our studies involved inducing glaucoma in Wistar and Sprague Dawley rats using lipopolysaccharide (LPS) and testing them in VFTZ and VM. We used Latanoprost and dorzolamide eye drops as standard drug candidates during the study. We evaluated the animals for intraocular pressure, retinal vasculature imaging, and anxiety using tonometry, ophthalmoscopy, and light and dark model techniques. Furthermore, we quantified the antioxidant parameters of the retina using UV spectroscopy. Our findings showed that animals with peripheral visual field loss in VFTZ took significantly more time to reach the goal and spent more time within the maze compared to normal or drug-treated animals (P < 0.001). Additionally, animals with compromised central visual field in VM spent more time in a particular arm and changed arms less frequently (P < 0.001) compared to normal or drug-treated animals. Moreover, we observed that glaucomatous rats exhibited elevated anxiety levels and impaired performance in the mazes, emphasizing the impact of vision loss on anxiety. Finally, the antioxidant and ATPase alterations in the retinal layers verified the glaucomatous changes in the experimental animals. Based on our remarkable findings, we strongly recommend the use of VFTZ and VM to evaluate visual field loss in animals.

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.