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result(s) for
"Vision Disorders - physiopathology"
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The Diabetes Visual Function Supplement Study (DiVFuSS)
by
Gerson, Jeffry D
,
Richer, Stuart P
,
Kowluru, Renu A
in
Adult
,
Aged
,
Antioxidants - administration & dosage
2016
BackgroundDiabetes is known to affect visual function before onset of retinopathy (diabetic retinopathy (DR)). Protection of visual function may signal disruption of mechanisms underlying DR.MethodsThis was a 6-month randomised, controlled clinical trial of patients with type 1 and type 2 diabetes with no retinopathy or mild to moderate non-proliferative retinopathy assigned to twice daily consumption of placebo or a novel, multi-component formula containing xanthophyll pigments, antioxidants and selected botanical extracts. Measurement of contrast sensitivity, macular pigment optical density, colour discrimination, 5-2 macular threshold perimetry, Diabetic Peripheral Neuropathy Symptoms, foveal and retinal nerve fibre layer thickness, glycohaemoglobin (HbA1c), serum lipids, 25-OH-vitamin D, tumour necrosis factor α (TNF-a) and high-sensitivity C reactive protein (hsCRP) were taken at baseline and 6 months. Outcomes were assessed by differences between and within groups at baseline and at study conclusion using meand ± SDs and t tests (p<0.05) for continuous variables.ResultsThere were no significant intergroup differences at baseline. At 6 months, subjects on active supplement compared with placebo had significantly better visual function on all measures (p values ranging from 0.008 to <0.0001), significant improvements in most serum lipids (p values ranging from 0.01 to 0.0004), hsCRP (p=0.01) and diabetic peripheral neuropathy (Fisher's exact test, p=0.0024) No significant changes in retinal thickness, HbA1c, total cholesterol or TNF-α were found between the groups.ConclusionsThis study provides strong evidence of clinically meaningful improvements in visual function, hsCRP and peripheral neuropathy in patients with diabetes, both with and without retinopathy, and without affecting glycaemic control.Trial registration numberwww.ClinicalTrials.gov Identifier: NCT01646047
Journal Article
Collagens and proteoglycans of the cornea: importance in transparency and visual disorders
by
Malecaze, Francois
,
Massoudi, Dawiyat
,
Galiacy, Stephane D.
in
Animals
,
Biomedical and Life Sciences
,
Biomedicine
2016
The cornea represents the external part of the eye and consists of an epithelium, a stroma and an endothelium. Due to its curvature and transparency this structure makes up approximately 70 % of the total refractive power of the eye. This function is partly made possible by the particular organization of the collagen extracellular matrix contained in the corneal stroma that allows a constant refractive power. The maintenance of such an organization involves other molecules such as type V collagen, FACITs (fibril-associated collagens with interrupted triple helices) and SLRPs (small leucine-rich proteoglycans). These components play crucial roles in the preservation of the correct organization and function of the cornea since their absence or modification leads to abnormalities such as corneal opacities. Thus, the aim of this review is to describe the different corneal collagens and proteoglycans by highlighting their importance in corneal transparency as well as their implication in corneal visual disorders.
Journal Article
Accuracy of a commonly used mobile ophthalmology application’s vision assessment tools in measuring five vision assessment parameters
by
Phan, Tavis
,
Riaz, Kamran M.
,
Cottom, Savannah
in
692/699/3161/3174
,
692/699/3161/3178
,
692/700/139/1735
2024
Background/Objectives
The use of mobile ophthalmology applications (MOA) is increasing, but many of these tools have not been validated. This study was performed to assess the accuracy of a popular MOA,
Eye Handbook
, in measuring five commonly-tested vision assessment parameters (distance visual acuity (DVA), near visual acuity (NVA), colour vision testing (CVT), contrast sensitivity (CS), and pupillary distance (PD)) was compared with traditional vision assessment methods (TVAM) [i.e. Snellen chart, Rosenbaum near card, Ishihara, Pelli Robson test, etc.] performed in the eye clinic setting.
Subjects/Methods
Prospective crossover clinical trial of 129 patients meeting inclusion criteria.
Results
Participants averaged significantly better DVA (
p
= 0.0008), NVA (
p
< 0.0001), and CVT (
p
= 0.0105) in the MOA than the TVAM, but all three MOA assessments were predictive of the TVAM values. CS was significantly better with the MOA (
p
< 0.0001). Linear regression and Spearman correlation tests were applied to assess the effect of CS on NVA, which showed no clear relationship between the difference in NVA and the difference in CS. PD using the two methods was in agreement with no significant difference (
p
= 0.2889).
Conclusion
The studied MOA offers an effective means of measuring four common vision parameters: DVA, NVA, CVT, and PD. The MOA can potentially be used by eye care providers, health care providers, and patients, both as a screening tool with correction factor and to monitor ocular pathologies. Atypical MOA measurements should prompt testing in the clinic with formal TVAMs.
Journal Article
Cognitive Level Enhancement through Vision Exams and Refraction (CLEVER): study protocol for a randomised controlled trial
2025
Background
Longitudinal observational studies have found an association between vision impairment and accelerated decline in cognition. However, no randomised trials have assessed the possible benefit of vision correction on cognitive change. We present the protocol for a three-year randomised controlled trial designed to assess the impact of spectacles for distance and/or near vision correction on cognitive change among community-dwelling elderly participants in India.
Methods
Cognitive Level Enhancement through Vision Exams and Refraction (CLEVER) is a single-centre, open-label, parallel-group, individually-randomised trial. Participants (760 total, 380 in each arm) aged ≥ 60 years with correctable vision impairment at distance and/or near (presenting visual acuity < 6/18 in the better-seeing eye and improving to > = 6/18 with spectacles and/or presenting near vision worse than N6 at 40 cm and improving to N6 with spectacles), normal hearing (able to repeat at least three out of six words whispered from a 50 cm distance in the better ear) and normal cognition (Hindi Mini-mental Status Examination score > 18/31) will be enrolled. After a comprehensive eye examination, intervention group participants will receive distance, near, or bifocal spectacles, while controls will receive a prescription and spectacles at the end of the trial. The primary outcome will be the three-year change in Longitudinal Aging Study in India–Diagnostic Assessment of Dementia (LASI DAD) global cognitive factor score, with and without adjustment for baseline score, age, gender, education and other potential confounders.
Conclusion
CLEVER is designed to assess the effectiveness of spectacles as a low-cost intervention to prevent or delay cognitive decline.
Trial registration
This trial is registered with ClinicalTrials.gov, number NCT05458323, February 15, 2023.
Journal Article
Digital therapeutics using virtual reality‐based visual perceptual learning for visual field defects in stroke: A double‐blind randomized trial
2024
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.
Journal Article
Mobility improvement of patients with peripheral visual field losses using novel see-through digital spectacles
by
Shousha, Mohamed Abou
,
Cook, Jane C.
,
Eleiwa, Taher K.
in
Algorithms
,
Augmented reality
,
Binocular vision
2020
To evaluate see-through Augmented Reality Digital spectacles (AR DSpecs) for improving the mobility of patients with peripheral visual field (VF) losses when tested on a walking track.
Prospective Case Series.
21 patients with peripheral VF defects in both eyes, with the physical ability to walk without assistance.
We developed the AR DSpecs as a wearable VF aid with an augmented reality platform. Image remapping algorithms produced personalized visual augmentation in real time based on the measured binocular VF with the AR DSpecs calibration mode. We tested the device on a walking track to determine if patients could more accurately identify peripheral objects.
We analyzed walking track scores (number of recognized/avoided objects) and eye tracking data (six gaze parameters) to measure changes in the kinematic and eye scanning behaviors while walking, and assessed a possible placebo effect by deactivating the AR DSpecs remapping algorithms in random trials.
Performance, judged by the object detection scores, improved with the AR DSpecs (P<0.001, Wilcoxon rank sum test) with an average improvement rate of 18.81%. Two gaze parameters improved with the activated algorithm (P<0.01, paired t-test), indicating a more directed gaze on the central path with less eye scanning. Determination of the binocular integrated VF with the DSpecs correlated with the integrated standard automated perimetry (R = 0.86, P<0.001), mean sensitivity difference 0.8 ± 2.25 dB (Bland-Altman).
AR DSpecs may improve walking maneuverability of patients with peripheral VF defects by enhancing detection of objects in a testing environment.
Journal Article
Optic disc haemorrhages at baseline as a risk factor for poor outcome in the Idiopathic Intracranial Hypertension Treatment Trial
by
Thurtell, Matthew J
,
Wall, Michael
in
Acetazolamide - therapeutic use
,
Adult
,
Carbonic Anhydrase Inhibitors - therapeutic use
2017
BackgroundThe risk of optic disc haemorrhages on visual outcome in idiopathic intracranial hypertension (IIH) is unknown. We report the type and frequency of optic disc haemorrhages and other funduscopic abnormalities at baseline in the study eye of the 133 subjects enrolled in the Idiopathic Intracranial Hypertension Treatment Trial completing 6 months of follow-up.MethodsWe reviewed optic disc photographs to tabulate the frequency and type of optic disc haemorrhages, other funduscopic abnormalities and papilloedema grades of the study eye at baseline and analyse if their presence is associated with a poor visual outcome.Results27.2% of subjects had nerve fibre layer haemorrhages in at least one eye. Five of seven, 71% of subjects that met criteria for treatment failure, had nerve fibre layer haemorrhages in at least one eye (Fisher's exact test: p=0.02). There was a good correlation between presence of nerve fibre layer haemorrhages and Frisén grade (Spearman's correlation, p=0.002; r=0.271). Subjects with nerve fibre layer haemorrhages had a higher cerebrospinal fluid pressure (40.0 mm water, p=0.04). There was poor correlation between nerve fibre layer haemorrhages at baseline and the perimetric mean deviation change at 6 months. Cotton wool spots were present in 4% of subjects, exudates in 3% and pseudodrusen in 4%.ConclusionsNerve fibre layer haemorrhages are common in patients with IIH with mild visual loss and correlate with the severity of the papilloedema. They occur more frequently in treatment failure subjects and therefore may be associated with poor visual outcomes.Trial registration number NCT01003639, Post-results.
Journal Article
Accommodative response in children with attention deficit hyperactivity disorder (ADHD): the influence of accommodation stimulus and medication
by
Barrett, Brendan T
,
Jiménez Raimundo
,
Redondo Beatríz
in
Attention deficit hyperactivity disorder
,
Binocular vision
,
Children
2020
BackgroundThere are claims that ocular accommodation differs in children with attention deficit hyperactivity disorder (ADHD) compared to typically developing children. We examined whether the accommodation response in ADHD children is influenced by changing the stimulus to accommodation in an attempt modify the level of attentional engagement or by medication for the condition.MethodsWe measured the accommodative response and pupil diameter using a binocular, open-field autorefractor in non-medicated and medicated children with ADHD (n = 22, mean age = 10.1 ± 2.4 years; n = 19; mean age = 11.0 ± 3.8 years; respectively) and in an age-matched control group (n = 22; mean age = 10.6 ± 1.9 years) while participants were asked to maintain focus on (i) a high-contrast Maltese cross, (ii) a frame of a cartoon movie (picture) and (iii) a cartoon movie chosen by the participant. Each stimulus was viewed for 180 s from a distance of 25 cm, and the order of presentation was randomised.ResultsGreater lags of accommodation were present in the non-medicated ADHD in comparison to controls (p = 0.023, lags of 1.10 ± 0.56 D and 0.72 ± 0.57 D, respectively). No statistically significant difference in the mean accommodative lag was observed between medicated ADHD children (lag of 1.00 ± 0.44D) and controls (p = 0.104) or between medicated and non-medicated children with ADHD (p = 0.504). The visual stimulus did not influence the lag of accommodation (p = 0.491), and there were no significant group-by-stimulus interactions (p = 0.935). The variability of accommodation differed depending on the visual stimulus, with higher variability for the picture condition compared to the cartoon-movie (p < 0.001) and the Maltese cross (p = 0.006). In addition, the variability yielded statistically significant difference for the main effect of time-on-task (p = 0.027), exhibiting a higher variability over time. However, no group differences in accommodation variability were observed (p = 0.935).ConclusionsChildren with ADHD have a reduced accommodative response, which is not influenced by the stimulus to accommodation. There is no marked effect of medication for ADHD on accommodation accuracy.
Journal Article
The effects of temporal pressure on obstacle negotiation and gaze behaviour in young adults with simulated vision loss
by
Pardhan, Shahina
,
Timmis, Matthew A.
,
Zult, Tjerk
in
692/499
,
692/698/1671/1811
,
692/699/3161/3178
2019
Individuals with vision loss adapt their locomotion and gaze behaviour to safely negotiate objects in temporally unconstrained situations. However, everyday activities are often performed under time-pressure. We investigated the effects of blur on anxiety, movement kinematics and gaze behaviour during the negotiation of a floor-based obstacle under three amounts of pressure: 1) no-pressure; 2) tonal-pressure: an intermittent tone was played at a constant frequency; 3) tonal + time pressure: the intermittent tone increased in frequency and participants had to walk 20% faster to reach the end of the lab. Irrespective of the amount of pressure, the blurred vs. normal vision group reported 32% more anxiety, lifted the lead foot 43% higher and 10% slower over the obstacle, and looked 6% longer and 6% more frequently ahead of the obstacle. In the tonal + time pressure vs. no-pressure condition, both groups were more anxious, showed adaptations in movement kinematics related to walking faster, and adopted a ‘checking strategy’ by shortening their fixation durations at the obstacle. These results show that irrespective of temporal pressure, the blurred vision group remained more cautious as to how the lead foot negotiated the obstacle, in order to reduce the chance of tripping during crossing.
Journal Article
The effect of visual support strategies on the quality of life of children with cerebral palsy and cerebral visual impairment/perceptual visual dysfunction in Nigeria: study protocol for a randomized controlled trial
2019
Background
Cerebral visual impairment (CVI), including perceptual visual dysfunction (PVD), is common in children with cerebral palsy (CP). Inventories of questions relating to practical aspects of visual perception in everyday life, in particular the closed-ended Insight Questions Inventory (IQI), can be used to assess CVI/PVD. Studies linking responses to the inventory with specific visual support strategies, aimed at modifying the child’s environment and/or behaviour to minimize the impact of the CVI/PVD, have been piloted. The IQI and tailored strategies have not been used in an African population, nor have they been tested in a controlled trial. This trial will compare the effectiveness of the IQI and linked visual support strategies versus general supportive treatments on the quality of life of children with CVI/PVD and CP through a randomized controlled trial.
Methods/design
This is a prospective, double-blind, parallel-arm, randomized controlled trial. The primary outcome is change in quality of life scores between the two arms of the trial at 6 weeks, assessed using the Paediatric Quality of Life Inventory (PedsQL) generic 4.0 and CP 3.0 module. All children will undergo baseline assessment including the Open Questions Inventory, IQI, PedsQL 3.0, PedsQL 4.0 generic, and the Strengths and Difficulties Questionnaire (SDQ). Eligible children with CP aged 4 years to < 16 years will be stratified and blocked by the age groups 4–9 and 10 to < 16 years and by Gross Motor Function Classification System (GMFCS) levels 1–3 and 4–5. Families in the intervention arm will receive tailored insight visual support strategies and telephone calls during the 6-week trial period. The control arm will receive standard treatment and the intervention after the 6-week trial period. Follow-up interviews will be performed in both arms at 6 weeks with a repeat administration of the PedsQL CP 4.0 and 3.0, the IQI and the SDQ. Secondary outcomes include a change in functional vision.
Discussion
This randomized controlled trial will provide evidence of the effectiveness of this intervention for children with CP in a resource-poor setting.
Trial registration
Pan African Clinical Trials Registration,
PACTR201612001886396
. Registered on 3 December 2016.
Journal Article