Characterizing the Randot Preschool stereotest: Testability, norms, reliability, specificity and sensitivity in children aged 2-11 years.

PURPOSE: To comprehensively assess the Randot Preschool stereo test in young children, including testability, normative values, test/retest reliability and sensitivity and specificity for detecting binocular vision disorders. METHODS: We tested 1005 children aged 2-11 years with the Randot Preschool stereo test, plus a cover/uncover test to detect heterotropia. Monocular visual acuity was assessed in both eyes using Keeler Crowded LogMAR visual acuity test for children aged 4 and over. RESULTS: Testability was very high: 65% in two-year-olds, 92% in three-year-olds and ~100% in older children. Normative values: In 389 children aged 2-5 with apparently normal vision, 6% of children scored nil (stereoblind). In those who obtained a threshold, the mean log threshold was 2.06 log10 arcsec, corresponding to 114 arcsec, and the median threshold was 100 arcsec. Most older children score 40 arcsec, the best available score. We found a small sex difference, with girls scoring slightly but significantly better. Test/retest reliability: ~99% for obtaining any score vs nil. Agreement between stereo thresholds is poor in children aged 2-5; 95% limit of agreement = 0.7 log10 arcsec: five-fold change in stereo threshold may occur without any change in vision. In children over 5, the test essentially acts only as a binary classifier since almost all non-stereoblind children score 40 arcsec. Specificity (true negative rate): >95%. Sensitivity (true positive rate): poor, <50%, i.e. around half of children with a demonstrable binocular vision abnormality score well on the Randot Preschool. CONCLUSIONS: The Randot Preschool is extremely accessible for even very young children, and is very reliable at classifying children into those who have any stereo vision vs those who are stereoblind. However, its ability to quantify stereo vision is limited by poor repeatability in children aged 5 and under, and a very limited range of scores relevant to children aged over 5.

ASTEROID: A New Clinical Stereotest on an Autostereo 3D Tablet.

PURPOSE: To describe a new stereotest in the form of a game on an autostereoscopic tablet computer designed to be suitable for use in the eye clinic and present data on its reliability and the distribution of stereo thresholds in adults. METHODS: Test stimuli were four dynamic random-dot stereograms, one of which contained a disparate target. Feedback was given after each trial presentation. A Bayesian adaptive staircase adjusted target disparity. Threshold was estimated from the mean of the posterior distribution after 20 responses. Viewing distance was monitored via a forehead sticker viewed by the tablet's front camera, and screen parallax was adjusted dynamically so as to achieve the desired retinal disparity. RESULTS: The tablet must be viewed at a distance of greater than ∼35 cm to produce a good depth percept. Log thresholds were roughly normally distributed with a mean of 1.75 log10 arcsec = 56 arcsec and SD of 0.34 log10 arcsec = a factor of 2.2. The standard deviation agrees with previous studies, but ASTEROID thresholds are approximately 1.5 times higher than a similar stereotest on stereoscopic 3D TV or on Randot Preschool stereotests. Pearson correlation between successive tests in same observer was 0.80. Bland-Altman 95% limits of reliability were ±0.64 log10 arcsec = a factor of 4.3, corresponding to an SD of 0.32 log10 arcsec on individual threshold estimates. This is similar to other stereotests and close to the statistical limit for 20 responses. CONCLUSIONS: ASTEROID is reliable, easy, and portable and thus well-suited for clinical stereoacuity measurements. TRANSLATIONAL RELEVANCE: New 3D digital technology means that research-quality psychophysical measurement of stereoacuity is now feasible in the clinic.

Treating childhood intermittent distance exotropia: a qualitative study of decision making.

BACKGROUND: Engaging patients (parents/families) in treatment decisions is increasingly recognised as important and beneficial. Yet where the evidence base for treatment options is limited, as with intermittent distance exotropia (X(T)), this presents a challenge for families and clinicians. The purpose of this study was to explore how decisions are made in the management and treatment of X(T) and what can be done to support decision-making for clinicians, parents and children. METHODS: This was a qualitative study using face to face interviews with consultant ophthalmologists and orthoptists, and parents of children with X(T). Interview data were analysed using the constant comparative method. RESULTS: The drivers for clinicians in treatment decision-making for X(T) were the proportion of time the strabismus is manifest and parents' views. For parents, decisions were influenced by: fear of bullying and, to a lesser degree, concerns around the impact of the strabismus on their child's vision. Uncertainty around the effectiveness of treatment options caused difficulties for some clinicians when communicating with parents. Parental understanding of the nature of X(T) and rationale for treatment often differed from that of the clinicians, and this affected their involvement in decision-making. Though there were good examples of shared decision-making and parent and child engagement some parents said the process felt rushed and they felt excluded. Parents reported that clinicians provided sufficient information in consultations but they had difficulties in retaining verbal information to convey to other family members. CONCLUSIONS: Overall parents were happy with the care their child received but there is scope for better parent and (where appropriate) child engagement in decision-making. There was an expressed need for written information about X(T) to reinforce what was given verbally in consultations and to share with other family members. Access could be via the hospital website, along with videos or blogs from parents and children who have undergone the various management options. A method of assisting clinicians to explain the treatment options, together with the uncertainties, in a clear and concise way could be of particular benefit to orthoptists who have the most regular contact with parents and children, and are more likely to suggest conservative treatments such as occlusion and minus lenses.

Effect of cataract surgery on cognition, mood, and visual hallucinations in older adults.

PURPOSE: To assess the impact of cataract surgery on cognition, mood, and visual hallucinations in a cohort of patients aged 75 years and older. SETTING: Secondary care ophthalmology unit in Northeast England. DESIGN: Prospective observational cohort study. METHODS: Participants aged 75 years or older with bilateral cataract and scheduled for cataract surgery were recruited consecutively. Participants were assessed preoperatively and followed for 1 year postoperatively. Cognition was assessed using the revised Addenbrooke's Cognitive Examination (ACE-R), mood was measured with the 15-item Geriatric Depression Scale, visual hallucinations were elicited using the North East Visual Hallucinations Inventory, and visual acuity was assessed using a logMAR chart. RESULTS: One hundred twelve participants were recruited at baseline; 91 (81%) completed 1 year of follow-up. Significant improvements in ACE-R scores were seen between baseline and 1 year postoperatively (95% confidence interval for improvement, 0.5-2.8; P = .005). Improved cognition did not correlate with improved visual acuity (r = -0.13, P = .22). No significant changes in mood were seen during the course of the study (P = .314, repeated-measures 1-way analysis of variance). Complete resolution of complex visual hallucinations occurred in 2 patients after surgery. CONCLUSIONS: Small improvements in cognition and reports of resolved complex visual hallucinations indicate that the benefits of cataract surgery might extend beyond visual improvement. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Surrendering control, or nothing to lose: Parents' preferences about participation in a randomised trial of childhood strabismus surgery.

BACKGROUND: Intermittent exotropia is the most common form of divergent strabismus (squint) in children. Evidence regarding its optimum management is limited. A pilot randomised controlled trial has recently been completed (Surgery versus Active Monitoring in Intermittent Exotropia trial) to determine the feasibility of a full randomised controlled trial. PURPOSE: To identify drivers for and barriers against parents' participation in Surgery versus Active Monitoring in Intermittent Exotropia and to seek their views on information received, the need for randomisation, and enhancing acceptability. METHODS: Multiple method qualitative study using semi-structured telephone interviews to explore parents' motivations and trial screening logs to provide an indication of common barriers. Exploratory thematic analysis identified key themes. RESULTS: A total of 48 interviews were conducted (14 participants; 34 non-participants). Barriers included no desire for surgery/preference to 'wait and see', wanting surgery immediately, feeling uncomfortable about 'surrendering control' over decision-making/being managed 'at random', lack of confidence in the effectiveness of surgery, believing the risks outweighed the benefits, and lack of trust. Drivers included desiring surgery, 'nothing to lose', benefits offsetting the risks, and being in a trial would result in better care. Some also mentioned 'doing their bit' for research. Suggestions for enhancing acceptability included allowing choice of treatment group, giving more time for decision-making, expanding on information given, and improving communication. Many felt the necessity of randomisation was adequately explained, but there was some indication that it was misunderstood. Information extracted from the screening logs of 80/89 eligible non-participants indicated the most prevalent barrier was not wanting surgery/preferring to observe (56%), followed by desiring surgery straightaway (15%). Opposition to randomisation/wanting to retain control was recorded in 9% of cases as was the belief that the child's squint was not severe enough to warrant surgery. LIMITATIONS: Interviews were not audio-recorded. Not all who consented to interview could be contacted, although the response/contact rate was good (48/62). A few parents did not provide reasons for refusing the trial. CONCLUSION: Opposition to surgery and concerns about surrendering control were common obstacles to participation, whereas parents keen for their child to undergo the operation but happy to defer tended to embrace a 'nothing to lose' attitude. Many non-participants would have consented if allowed to choose group, although most of these would have chosen observation. While most parents felt happy with information given and that randomisation was adequately explained, it is of concern that there may be some misunderstanding, which should be addressed in any trial. These findings will inform future trials in childhood exotropia, for example, consideration of preference arms and improving communication. Lessons learnt from the Surgery versus Active Monitoring in Intermittent Exotropia trial could prove valuable to paediatric and surgical trials generally.

A systematic review of the effectiveness of treatments in altering the natural history of intermittent exotropia.

Evidence of effectiveness of interventions for treatment of childhood intermittent exotropia, X(T), is unclear. We conducted a systematic review to locate, appraise and synthesise evidence of effectiveness, including twelve electronic databases, supplemented with hand searches and expert contact. We included randomised controlled trials, quasi-experimental and cohort studies with a comparison group examining interventions for divergence excess, simulated divergence excess or basic type X(T) in children, up to and including 18 years of age, followed for at least 6 months. Dual data extraction and critical appraisal were conducted and a narrative synthesis undertaken. Eleven studies satisfied the eligibility criteria. Seven examined the comparative effectiveness of two surgical procedures; four compared surgery with other interventions, including botulinum toxin A therapy, orthoptic exercises, occlusion, binocular vision training and watchful waiting. The evidence retrieved was of limited extent and quality with differences across studies in terms of outcome assessment and most appropriate time-point for measuring long-term outcomes. There were mixed outcomes when comparing unilateral recession/resection (R&R) with bilateral lateral rectus recession (BLR) on improving angle of deviation, which makes it difficult to recommend either surgical option with confidence. While non-surgical interventions appear less effective in terms of improving angle of deviation, they are rarely associated with adverse outcomes. Given the limited evidence base, better designed studies are required to address the question of the most effective management for treatment of childhood X(T). Importantly, consensus is required on what constitutes a successful outcome as well as agreement on how this should be measured.

A randomized trial of increasing patching for amblyopia.

OBJECTIVE: After treatment with refractive correction and patching, some patients have residual amblyopia resulting from strabismus or anisometropia. We conducted a clinical trial to evaluate the effectiveness of increasing prescribed daily patching from 2 to 6 hours in children with stable residual amblyopia. DESIGN: Prospective, randomized, multicenter clinical trial. PARTICIPANTS: A total of 169 children aged 3 to <8 years (mean, 5.9 years) with stable residual amblyopia (20/32-20/160) after 2 hours of daily patching for at least 12 weeks. INTERVENTION: Random assignment to continue 2 hours of daily patching or increase patching time to an average of 6 hours/day. MAIN OUTCOME MEASURES: Best-corrected visual acuity (VA) in the amblyopic eye after 10 weeks. RESULTS: Baseline VA was 0.44 logarithm of the minimum angle of resolution (logMAR) (20/50(-2)). Ten weeks after randomization, amblyopic eye VA had improved an average of 1.2 lines in the 6-hour group and 0.5 line in the 2-hour group (difference in mean VA adjusted for acuity at randomization = 0.6 line; 95% confidence interval, 0.3-1.0; P = 0.002). Improvement of 2 or more lines occurred in 40% of participants patched for 6 hours versus 18% of those who continued to patch for 2 hours (P = 0.003). CONCLUSIONS: When amblyopic eye VA stops improving with 2 hours of daily patching, increasing the daily patching dosage to 6 hours results in more improvement in VA after 10 weeks compared with continuing 2 hours daily.

The association between diagnosed glaucoma and cataract and cognitive performance in very old people: cross-sectional findings from the newcastle 85+ study.

PURPOSE: Common age-related eye diseases including glaucoma, cataract and age-related macular degeneration (AMD) have been proposed to be associated with dementia. Few studies have examined the relationship between cognition and cataract or glaucoma. We explored the association between cognition and cataract and glaucoma diagnoses in community-dwelling 85-year-olds. METHODS: Cross-sectional analysis of data from the Newcastle 85+ Study. Diagnoses of eye disease were extracted from family practice records. Cognitive performance was assessed by the standardized mini-mental state examination (sMMSE) and the sMMSE-blind (MMblind). Relationships between glaucoma diagnosis or cataract diagnosis and lower cognition were examined using ordinal logistic regression. RESULTS: Complete data were available for 839 participants. Of these, 36.0% (302/839) had recorded previous cataract surgery, 11.2% (94/839) untreated cataract and 7.9% (66/839) diagnosed glaucoma. Glaucoma diagnosis was associated with lower sMMSE results (odds ratio [OR] 1.76, 95% confidence interval [CI] 1.05-2.95); but not lower MMblind (OR 1.17, 95% CI 0.65-2.12). When compared to no cataract, cataract diagnosis (treated and untreated combined) was associated with higher sMMSE (OR 0.55, 95% CI 0.38-0.79) and MMblind (OR 0.51, 95% CI 0.34-0.76). Previously treated cataract was associated with higher sMMSE (OR 0.72, 95% CI 0.59-0.88) and MMblind (OR 0.68, 95% CI 0.55-0.85). Untreated cataract was not significantly associated with sMMSE (OR 0.65, 95% CI 0.36-1.19) or MMblind (OR 0.73, 95% CI 0.39-1.36). CONCLUSIONS: This large epidemiological study of 85-year-olds found that lower sMMSE but not MMblind was associated with glaucoma diagnosis, suggesting the association may be driven by poor vision. Cataract diagnosis was associated with higher sMMSE and MMblind. Reasons for this observation are unclear but may relate to enhanced help-seeking behavior in people with diagnosed cataract.

Visual exploration in Parkinson's disease and Parkinson's disease dementia.

Parkinson's disease, typically thought of as a movement disorder, is increasingly recognized as causing cognitive impairment and dementia. Eye movement abnormalities are also described, including impairment of rapid eye movements (saccades) and the fixations interspersed between them. Such movements are under the influence of cortical and subcortical networks commonly targeted by the neurodegeneration seen in Parkinson's disease and, as such, may provide a marker for cognitive decline. This study examined the error rates and visual exploration strategies of subjects with Parkinson's disease, with and without cognitive impairment, whilst performing a battery of visuo-cognitive tasks. Error rates were significantly higher in those Parkinson's disease groups with either mild cognitive impairment (P = 0.001) or dementia (P < 0.001), than in cognitively normal subjects with Parkinson's disease. When compared with cognitively normal subjects with Parkinson's disease, exploration strategy, as measured by a number of eye tracking variables, was least efficient in the dementia group but was also affected in those subjects with Parkinson's disease with mild cognitive impairment. When compared with control subjects and cognitively normal subjects with Parkinson's disease, saccade amplitudes were significantly reduced in the groups with mild cognitive impairment or dementia. Fixation duration was longer in all Parkinson's disease groups compared with healthy control subjects but was longest for cognitively impaired Parkinson's disease groups. The strongest predictor of average fixation duration was disease severity. Analysing only data from the most complex task, with the highest error rates, both cognitive impairment and disease severity contributed to a predictive model for fixation duration [F(2,76) = 12.52, P ≤ 0.001], but medication dose did not (r = 0.18, n = 78, P = 0.098, not significant). This study highlights the potential use of exploration strategy measures as a marker of cognitive decline in Parkinson's disease and reveals the efficiency by which fixations and saccades are deployed in the build-up to a cognitive response, rather than merely focusing on the outcome itself. The prolongation of fixation duration, present to a small but significant degree even in cognitively normal subjects with Parkinson's disease, suggests a disease-specific impact on the networks directing visual exploration, although the study also highlights the multi-factorial nature of changes in exploration and the significant impact of cognitive decline on efficiency of visual search.

Surgery versus Active Monitoring in Intermittent Exotropia (SamExo): study protocol for a pilot randomised controlled trial.

BACKGROUND: Childhood intermittent exotropia [X(T)] is a type of strabismus (squint) in which one eye deviates outward at times, usually when the child is tired. It may progress to a permanent squint, loss of stereovision and/or amblyopia (reduced vision). Treatment options for X(T) include eye patches, glasses, surgery and active monitoring. There is no consensus regarding how this condition should be managed, and even when surgery is the preferred option clinicians disagree as to the optimal timing. Reports on the natural history of X(T) are limited, and there is no randomised controlled trial (RCT) evidence on the effectiveness or efficiency of surgery compared with active monitoring. The SamExo (Surgery versus Active Monitoring in Intermittent Exotropia) pilot study has been designed to test the feasibility of such a trial in the UK. DESIGN: an external pilot patient randomised controlled trial. SETTING: four UK secondary ophthalmology care facilities at Newcastle NHS Hospitals Foundation Trust, Sunderland Eye Infirmary, Moorfields Eye Hospital and York NHS Trust. PARTICIPANTS: children aged between 6 months and 16 years referred with suspected and subsequently diagnosed X(T). Recruitment target is a total of 144 children over a 9-month period, with 120 retained by 9-month outcome visit.Randomisation: permuted blocks stratified by collaborating centre, age and severity of X(T). INTERVENTIONS: initial clinical assessment; randomisation (eye muscle surgery or active monitoring); 3-, 6- and 9-month (primary outcome) clinical assessments; participant/proxy completed questionnaire covering time and travel costs, health services use and quality of life (Intermittent Exotropia Questionnaire); qualitative interviews with parents to establish reasons for agreeing or declining participation in the pilot trial. OUTCOMES: recruitment and retention rates; nature and extent of participation bias; nature and extent of biases arising from crossover or loss to follow-up; reasons for agreeing/declining participation; variability of cure rates (to inform power calculations for a definitive RCT); completion rates of outcome measures. DISCUSSION: The SamExo pilot trial will provide important pointers regarding the feasibility of a full RCT of immediate surgery versus deferred surgery/active monitoring. The results of this pilot, including differences in cure rates, will inform the design of a definitive RCT. TRIAL REGISTRATION: ISRCTN44114892.

Surgical intervention in childhood intermittent exotropia: current practice and clinical outcomes from an observational cohort study.

PURPOSE: To describe surgical outcomes in intermittent exotropia (X(T)), and to relate these to preoperative and surgical characteristics. METHODS: 87 children (aged <11 years) underwent surgery in 18 UK centres; review data (mean 21 months post-surgery) were available for 72. The primary outcome measure was motor/sensory outcome (angle and stereoacuity). The secondary outcome measure was satisfactory control assessed by Newcastle Control Score (NCS). RESULTS: 35% of patients had excellent, 28% had fair and 37% had poor primary outcome. Preoperative and surgical characteristics did not influence primary outcome. Satisfactory control was achieved in 65% of patients, while X(T) remained/recurred in 20%. Persistent over-correction occurred in 15% of children. There was no relationship between over-correction and preoperative characteristics or surgical dose/type. Median angle improved by 12 prism dioptres (PD) at near and 19 PD at distance (p<0.001). Median NCS improved by 5 (p<0.001). 40% of those initially over-corrected remained so by last postoperative assessment; no relationship was found between an initial over-correction and good outcome. CONCLUSIONS: Whilst excellent motor/sensory outcome was achieved in one-third and satisfactory control in two-thirds of patients, the 37% poor outcome and 15% persistent over-correction rate is of concern. Surgical dose was similar in those under- and over-corrected, suggesting that over-corrections cannot be avoided merely by getting the dosage right: a randomised controlled trial (RCT) would shed light on this issue. Initial over-correction did not improve the chance of a good outcome, supporting the growing literature on this topic and further highlighting the need for randomised controlled trials of X(T) surgery.

The impact of visual impairment on Mini-Mental State Examination Scores in the Newcastle 85+ study.

BACKGROUND: cognitive test scores and visual acuity are strongly associated in older people. This may be due to poor vision limiting performance on cognitive tasks specifically requiring vision, or an association between visual and neurodegenerative disorders. OBJECTIVE: to explore, using data from the Newcastle 85+ cohort study, the impact of sight impairment (SI) on Mini-Mental State Examination (MMSE) scores and whether reduced scores among SI participants are limited to tasks requiring vision. RESULTS: of 839 participants aged 85 years, 44 (5.2%) were registered SI. Median (inter-quartile range) sMMSE scores were 25 (22-29) for SI and 28 (25-29) for non-SI participants (P=0.006). SI participants had lower subscale scores on tasks requiring vision (P<0.001 for each) but also for some subscale scores not obviously requiring vision: orientation (P=0.018) and repetition (P=0.030). Excluding visual items, there was no significant difference in MMSE scores between those with/without SI. CONCLUSION: SI may be an obstacle to older people completing cognitive assessments including tasks requiring vision. People with SI also scored lower on some tasks not obviously requiring vision. An association between cognitive impairment and SI may exist beyond simply being unable to see the test material in cognitive tests.

The improving outcomes in intermittent exotropia study: outcomes at 2 years after diagnosis in an observational cohort.

BACKGROUND: The purpose of this study was to investigate current patterns of management and outcomes of intermittent distance exotropia [X(T)] in the UK. METHODS: This was an observational cohort study which recruited 460 children aged < 12 years with previously untreated X(T). Eligible subjects were enrolled from 26 UK hospital ophthalmology clinics between May 2005 and December 2006. Over a 2-year period of follow-up, clinical data were prospectively recorded at standard intervals from enrolment. Data collected included angle, near stereoacuity, visual acuity, control of X(T) measured with the Newcastle Control Score (NCS), and treatment. The main outcome measures were change in clinical outcomes (angle, stereoacuity, visual acuity and NCS) in treated and untreated X(T), 2 years from enrolment (or, where applicable, 6 months after surgery). Change over time was tested using the chi-square test for categorical, Wilcoxon test for non-parametric and paired-samples t-test for parametric data. RESULTS: At follow-up, data were available for 371 children (81% of the original cohort). Of these: 53% (195) had no treatment; 17% (63) had treatment for reduced visual acuity only (pure refractive error and amblyopia); 13% (50) had non surgical treatment for control (spectacle lenses, occlusion, prisms, exercises) and 17% (63) had surgery. Only 0.5% (2/371) children developed constant exotropia. The surgically treated group was the only group with clinically significant improvements in angle or NCS. However, 8% (5) of those treated surgically required second procedures for overcorrection within 6 months of the initial procedure and at 6-month follow-up 21% (13) were overcorrected. CONCLUSIONS: Many children in the UK with X(T) receive active monitoring only. Deterioration to constant exotropia, with or without treatment, is rare. Surgery appears effective in improving angle of X(T) and NCS, but rates of overcorrection are high.

Use of the PedsQL in childhood intermittent exotropia: estimates of feasibility, internal consistency reliability and parent-child agreement.

PURPOSE: To evaluate the PedsQLs performance in children with intermittent exotropia (X[T]) in terms of feasibility, internal consistency, floor-ceiling effects and levels of parent-child agreement. METHODS: Children with X(T) aged <12 years were recruited from 26 UK Hospital Eye Clinics/Orthoptic Departments. QOL was assessed using child (n = 166) and proxy (n = 392) versions of the PedsQLv4. Feasibility was assessed by percentage of missing responses; internal consistency by Cronbach's alpha and agreement by Bland-Altman plots and intraclass correlations. Analyses included age and gender comparisons. RESULTS: Missing response rates were no higher than 1.8%. Cronbach's alpha reached ≥ 0.70 on all but one parent-rated scale and on most child-rated Total, Psychosocial Summary and Social Functioning scales, but was <0.70 on most child-rated Physical, Emotional and School Functioning scales. On parent-rated scales, there were no floor effects; ceiling effects reached 27-56% in parents' Physical, Social and School Functioning. On child-rated scales, there were 0-1% floor effects and 0-28% ceiling effects. Parent-child agreement was fair to poor and varied by child's gender. CONCLUSIONS: Proxy-rated PedsQLs demonstrated good internal consistency/feasibility in parents of children with X(T); child-rated reports appeared acceptable, although caution is advised regarding Physical, Emotional and School Functioning scales in younger children. Low-fair agreement between proxy and self-ratings is common in paediatric QOL assessment, reiterating the importance of obtaining both perspectives. We encourage future studies to explore the influence of child's age and gender, and the relationship of the proxy respondent.