Validation of the brain injury associated visual impairment - impact questionnaire (BIVI-IQ).

PURPOSE: The Brain Injury associated Visual Impairment - Impact Questionnaire (BIVI-IQ) was developed to assess the impact of post-stroke visual impairment. The development of the questionnaire used robust methods involving stroke survivors and clinicians. The aim of this study was to assess the validity of the BIVI-IQ in a stroke population. METHODS: Stroke survivors with visual impairment were recruited from stroke units, outpatient clinics and non-healthcare settings. Participants were asked to complete questionnaire sets on three separate occasions; the BIVI-IQ at each visit with additional questionnaires at baseline and visit 2. Vision assessment and anchor questions from participants and clinicians were collected. The analysis included assessment of missing data, acceptability, Rasch model analysis, test-retest reliability, construct validity (NEI VFQ-25, EQ-5D-5L) and responsiveness to change. RESULTS: 316 stroke survivors completed at least one questionnaire of the 326 recruited. Mean age was 67 years and 64% were male. Adequate fit statistics to the Rasch model were reached (χ2 = 73.12, p = 0.02) with two items removed and thresholds of two adjusted, indicating validity and unidimensionality. Excellent test-retest reliability was demonstrated (ICC = 0.905) with a 3-month interval. Construct validity was demonstrated with a strong significant correlation to the NEI VFQ-25 (r = 0.837, p < 0.01). The BIVI-IQ also demonstrated responsiveness to change with significant differences identified between groups based on participant and clinician anchor questions (X2 = 23.29, p < 0.001; X2 = 24.56, p < 0.001). CONCLUSION: The BIVI-IQ has been shown to be valid and practical for 'everyday' use by clinicians and researchers to monitor vision-related quality of life in stroke survivors with visual impairment.

Behavioural performance improvement in visuomotor learning correlates with functional and microstructural brain changes.

A better understanding of practice-induced functional and structural changes in our brains can help us design more effective learning environments that provide better outcomes. Although there is growing evidence from human neuroimaging that experience-dependent brain plasticity is expressed in measurable brain changes that are correlated with behavioural performance, the relationship between behavioural performance and structural or functional brain changes, and particularly the time course of these changes, is not well characterised. To understand the link between neuroplastic changes and behavioural performance, 15 healthy participants in this study followed a systematic eye movement training programme for 30 min daily at home, 5 days a week and for 6 consecutive weeks. Behavioural performance statistics and eye tracking data were captured throughout the training period to evaluate learning outcomes. Imaging data (DTI and fMRI) were collected at baseline, after two and six weeks of continuous training, and four weeks after training ended. Participants showed significant improvements in behavioural performance (faster task completion time, lower fixation number and fixation duration). Spatially overlapping reductions in microstructural diffusivity measures (MD, AD and RD) and functional activation increases (BOLD signal) were observed in two main areas: extrastriate visual cortex (V3d) and the frontal part of the cerebellum/Fastigial Oculomotor Region (FOR), which are both involved in visual processing. An increase of functional activity was also recorded in the right frontal eye field. Behavioural, structural and functional changes were correlated. Microstructural change is a better predictor for long-term behavioural change than functional activation is, whereas the latter is superior in predicting instantaneous performance. Structural and functional measures at week 2 of the training programme also predict performance at week 6 and 10, which suggests that imaging data at an early stage of training may be useful in optimising practice environments or rehabilitative training programmes.

Health Inequalities Associated with Post-Stroke Visual Impairment in the United Kingdom and Ireland: A Systematic Review.

The aim of this study was to report on the health inequalities facing stroke survivors with visual impairments as described in the current literature. A systemic review of the literature was conducted to investigate the potential health inequalities facing stroke survivors with subsequent visual impairments. A quality-of-evidence and risk-of-bias assessment was conducted for each of the included articles using the appropriate tool dependent on the type of article. Only four articles discussed health inequalities affecting stroke survivors with visual impairment specifically. A further 23 articles identified health inequalities after stroke, and 38 reported on health inequalities within the visually impaired UK or Irish population. Stroke survivors with visual impairment face inconsistency in eye care provision nationally, along with variability in the assessment and management of visual disorders. The subgroups identified as most at risk were females; black ethnicity; lower socioeconomic status; older age; and those with lower education attainment. The issue of inconsistent service provision for this population must be addressed in future research. Further research must be conducted in order to firmly establish whether or not stroke survivors are at risk of the aforementioned sociodemographic and economic inequalities.

A pilot randomized controlled trial comparing effectiveness of prism glasses, visual search training and standard care in hemianopia.

OBJECTIVE: Pilot trial to compare prism therapy and visual search training, for homonymous hemianopia, to standard care (information only). METHODS: Prospective, multicentre, parallel, single-blind, three-arm RCT across fifteen UK acute stroke units. PARTICIPANTS: Stroke survivors with homonymous hemianopia. INTERVENTIONS: Arm a (Fresnel prisms) for minimum 2 hours, 5 days per week over 6 weeks. Arm b (visual search training) for minimum 30 minutes, 5 days per week over 6 weeks. Arm c (standard care-information only). INCLUSION CRITERIA: Adult stroke survivors (>18 years), stable hemianopia, visual acuity better than 0.5 logMAR, refractive error within ±5 dioptres, ability to read/understand English and provide consent. OUTCOMES: Primary outcomes were change in visual field area from baseline to 26 weeks and calculation of sample size for a definitive trial. Secondary measures included Rivermead Mobility Index, Visual Function Questionnaire 25/10, Nottingham Extended Activities of Daily Living, Euro Qual, Short Form-12 questionnaires and Radner reading ability. Measures were post-randomization at baseline and 6, 12 and 26 weeks. RANDOMIZATION: Randomization block lists stratified by site and partial/complete hemianopia. BLINDING: Allocations disclosed to patients. Primary outcome assessor blind to treatment allocation. RESULTS: Eighty-seven patients were recruited: 27-Fresnel prisms, 30-visual search training and 30-standard care; 69% male; mean age 69 years (SD 12). At 26 weeks, full results for 24, 24 and 22 patients, respectively, were compared to baseline. Sample size calculation for a definitive trial determined as 269 participants per arm for a 200 degree2 visual field area change at 90% power. Non-significant relative change in area of visual field was 5%, 8% and 3.5%, respectively, for the three groups. Visual Function Questionnaire responses improved significantly from baseline to 26 weeks with visual search training (60 [SD 19] to 68.4 [SD 20]) compared to Fresnel prisms (68.5 [SD 16.4] to 68.2 [18.4]: 7% difference) and standard care (63.7 [SD 19.4] to 59.8 [SD 22.7]: 10% difference), P=.05. Related adverse events were common with Fresnel prisms (69.2%; typically headaches). CONCLUSIONS: No significant change occurred for area of visual field area across arms over follow-up. Visual search training had significant improvement in vision-related quality of life. Prism therapy produced adverse events in 69%. Visual search training results warrant further investigation.

Clinical versus Evidence-based Rehabilitation Options for Post-stroke Visual Impairment.

The aim of this study was to identify which treatments for post-stroke visual impairment have a supportive evidence base, and which are being used in practice without supportive evidence. A systematic review of the literature reporting on the available treatment options was compared against the visual treatments used in the Vision In Stroke (VIS) study. Treatments were identified for visual field, visual neglect, visual perception and ocular motility disorders. Visual scanning therapies for hemianopia and neglect have an established evidence base. However, a number, such as typoscopes and advice options, have limited detail of their effectiveness and require further research.

A randomised controlled trial to compare the clinical and cost-effectiveness of prism glasses, visual search training and standard care in patients with hemianopia following stroke: a protocol.

INTRODUCTION: Homonymous hemianopia is a common and disabling visual problem after stroke. Currently, prism glasses and visual scanning training are proposed to improve it. The aim of this trial is to determine the effectiveness of these interventions compared to standard care. METHODS AND ANALYSIS: The trial will be a multicentre three arm individually randomised controlled trial with independent assessment at 6 week, 12 week and 26 week post-randomisation. Recruitment will occur in hospital, outpatient and primary care settings in UK hospital trusts. A total of 105 patients with homonymous hemianopia and without ocular motility impairment, visual inattention or pre-existent visual field impairment will be randomised to one of three balanced groups. Randomisation lists will be stratified by site and hemianopia level (partial or complete) and created using simple block randomisation by an independent statistician. Allocations will be disclosed to patients by the treating clinician, maintaining blinding for outcome assessment. The primary outcome will be change in visual field assessment from baseline to 26 weeks. Secondary measures will include the Rivermead Mobility Index, Visual Function Questionnaire 25/10, Nottingham Extended Activities of Daily Living, Euro Qual-5D and Short Form-12 questionnaires. Analysis will be by intention to treat. ETHICS AND DISSEMINATION: This study has been developed and supported by the UK Stroke Research Network Clinical Studies Group working with service users. Multicentre ethical approval was obtained through the North West 6 Research ethics committee (Reference 10/H1003/119). The trial is funded by the UK Stroke Association. Trial Registration: Current Controlled Trials ISRCTN05956042. Dissemination will consider usual scholarly options of conference presentation and journal publication in addition to patient and public dissemination with lay summaries and articles. TRIAL REGISTRATION: Current Controlled Trials ISRCTN05956042.

Accuracy of referrals for visual assessment in a stroke population.

PURPOSE: To evaluate accuracy of referrals from multidisciplinary stroke teams requesting visual assessments. PATIENTS AND METHODS: Multicentre prospective study undertaken in 20 acute Trust hospitals. Stroke survivors referred with suspected visual difficulty were recruited. Standardised screening/referral and investigation forms were used to document data on referral signs and symptoms, plus type and extent of visual impairment. RESULTS: Referrals for 799 patients were reviewed: 60% men, 40% women. Mean age at onset of stroke was 69 years (SD 14: range 1-94 years). Signs recorded by referring staff were nil in 58% and positive in the remainder. Symptoms were recorded in 87%. Diagnosis of visual impairment was nil in 8% and positive in the remainder. Sensitivity of referrals (on the basis of signs detected) was calculated as 0.42 with specificity of 0.52. Kappa statistical evaluation of agreement between referral and diagnosis of visual impairment was 0.428 (SE 0.017: 95% confidence interval of -0.048, 0.019). CONCLUSION: More than half of patient referrals were made despite no signs of visual difficulty being recorded by the referring staff. Visual impairment of varying severity was diagnosed in 92% of stroke survivors referred for visual assessment. Referrals were made based predominantly on visual symptoms and because of formal orthoptic liaison in Trusts involved.

Intervention for intermittent distance exotropia with overcorrecting minus lenses.

AIM: There are numerous treatment options for intermittent distance exotropia. The aim of this study is to evaluate the use of overcorrecting minus lenses as a primary treatment option for intermittent distance exotropia (IDEX) and determine ocular alignment status after 5 years from commencement of the study. METHODS: Prospective nonrandomised longitudinal cohort study in which 21 patients were recruited with a diagnosis of IDEX. Treatment was instigated with the minimum minus lens required to achieve control of the manifest deviation. The strength of lenses was reduced over time while monitoring the results of orthoptic measurements. The results were evaluated by nonparametric (Wilcoxon) and parametric (paired t-test) analysis. RESULTS: Thirteen female and eight male patients were recruited with a mean age of 5 years at the start of treatment. There was a significant reduction in angle of deviation after treatment. Overcorrecting lenses did not appear to induce myopia. Twenty-four per cent of the patients had a successful outcome, 28% had a good outcome, and 33% required surgery at a later date. CONCLUSIONS: Fifty-two per cent of the patients achieved a successful or good outcome with overcorrecting minus lenses alone, and this was maintained for at least 1 year follow-up. Those requiring surgery had been unable to wean out of lenses but had a successful outcome after one procedure. We recommend overcorrecting minus lenses as a primary treatment option for IDEX with the knowledge that surgery, if subsequently required, is safely delayed to an older age without prior loss of binocular vision.

Use of botulinum toxin in small-angle heterotropia and decompensating heterophoria: a review of the literature.

Botulinum toxin has been used extensively in strabismus management. However, less is published regarding its use in small-angled manifest deviations or decompensating heterophorias, where an alternative to surgery is required. The aim of this review is to look at the use and effectiveness of botulinum toxin in managing small-angled manifest deviations, both constant and intermittent, and decompensating heterophorias. These types of strabismus can prove difficult to manage, as the angle present is often too small for surgery to be advised, but it may still cause a cosmetic or symptom-producing problem. A search of the English speaking literature was undertaken using Medline facilities as well as a limited manual search of non-Medline journals and transactions. A brief overview is provided for mechanisms of action, complications and dose effects, and diagnostic and therapeutic uses of botulinum toxin. The main reported complications are those of ptosis, induced vertical deviation and subconjunctival haemorrhage. The higher the dose, the greater the risk of complications. In small-angle strabismus, botulinum toxin is reported as particularly useful in cases of acquired and acute-onset esotropia in aiding maintenance of binocular vision. It is useful for additional management of surgically under- or over-corrected esotropia, particularly for those with potential for binocular vision. Less effect is reported in primary exotropia versus primary esotropia. It is the management of choice for consecutive exotropia, particularly when patients have had previous multiple surgery and where there is a risk for postoperative diplopia. Botulinum toxin has a specific role in decompensated heterophoria, allowing the visual axes a chance to 'lock on' and subsequently maintain binocular vision. Successful outcomes are reported after 1-2 injections only but the results are best in cases of heterophoria with little near-distance angle disparity.

Long-term postoperative stability in infantile esotropia.

The purpose of this paper is to present the ocular motility status of a group of patients with infantile esotropia who underwent surgery before 2 years of age and were followed for a minimum period of 4 years until discharge from Ophthalmology and Orthoptic review. This retrospective review included 40 children with a diagnosis of infantile esotropia. There were 22 females and 18 males. The children were identified from surgical records between 1987 and 1992. Each child had surgery before the age of 2 years at an average age of 17 months (7 months to 22 months). Many patients (60%) achieved a small-angle (less than 20 prism dioptres), cosmetically acceptable strabismus. Nine patients (22.5%) achieved binocular vision postoperatively, five with microtropia, one with intermittent exotropia and three with bifoveal exophoria. The bifoveal patients did not exhibit high grade stereopsis, which may relate to the time of onset of infantile esotropia when development of cortical stereopsis is critical. Persistent amblyopia postoperatively was significantly associated with a poorer outcome and lack of binocular function.

The relationship between obesity and idiopathic intracranial hypertension.

OBJECTIVES: To evaluate the association between obesity and idiopathic intracranial hypertension (IIH) and establish whether there is a relationship with visual outcome. To calculate the prevalence and degree of obesity in a group of patients with IIH. METHODS: 34 patients (31 female and 3 male) were recruited between 1993 - 1997 with a diagnosis of IIH. Assessment included visual acuity, visual field assessment (Humphrey automated and Goldmann manual perimetry), fundus assessment and measurement of body mass index (BMI). Obesity was defined as a BMI of 30 kg/m2. RESULTS: 70.5% of patients were obese. The relative risk for obesity and IIH was significant at 8 (95%CI: 2,29). This increased to 17 (95%CI: 5,62) for obese females aged 16 to 24 years and 10 (95%CI: 3,35.5) for obese females aged 25 to 34 years. Morbid obesity (BMI > 40) was significantly associated with poor visual outcome. Serial obesity measures showed generally little change in weight over time and there was no correlation between weight change and visual improvement. CONCLUSIONS: This study has documented a relationship between obesity and IIH. A high degree of obesity was associated with a poor visual function and identified as a risk factor for poor outcome. Obesity may be an aetiological factor in this condition although it is unlikely to be the sole cause but more probably a precipitating factor. Weight loss is recommended although failure to lose weight is common. Any weight reduction programme must therefore be actively encouraged and monitored.

Assessment of visual function in idiopathic intracranial hypertension: a prospective study.

The visual function of 35 patients with a diagnosis of idiopathic intracranial hypertension was assessed prospectively over a 3 year period. In assessing the visual function of cases of idiopathic intracranial hypertension a number of tests were employed including visual field assessment with Humphrey and Goldmann perimeters and documentation of visual acuity and contrast sensitivity. Loss of visual function is the only serious complication and may occur early or late in the course of the condition. An appropriate and sensitive clinical assessment regime is therefore of importance in the outpatient situation. Visual field assessment was documented as the most sensitive to detection of visual loss, with statistically greater sensitivity in comparison with visual acuity and contrast sensitivity testing. Detection of asymptomatic visual loss indicates the necessity for visual monitoring to ensure detection of insidious visual loss. The types of visual field defects noted in this study were typical of anterior optic nerve pathology of raised intracranial pressure and commonly included arcuate defects, nasal steps and global constriction. Visual loss was noted at presentation and during follow-up in up to 87% of patients using Goldmann perimetry and up to 82% of patients using Humphrey perimetry. The visual status improved significantly throughout the follow-up period and the final visual outcome was excellent or good in 83% of patients.

Use of the distraction hearing test in children with congenital ocular motor apraxia.

Five of the 14 children with congenital ocular motor apraxia under Addenbrooke's Hospital Ophthalmology Department were assessed in tertiary audiology clinics. These referrals had been made after the children had failed to pass the 8-month hearing screen and second tier community-based assessment using distraction testing. In all cases they were found to have normal hearing on further assessment. The false positive response with the distraction test is likely to be due to the child's inability to initiate appropriate head and eye movements. We present a case report on a child with congenital ocular motor apraxia (COMA) at tertiary hearing assessment.