Modelling the cost-effectiveness of a newborn hearing screening programme; usability and pitfalls.

OBJECTIVE: The EUSCREEN project concerns the study of European vision and hearing screening programmes. Part of the project was the development of a cost-effectiveness model to analyse such programmes. We describe the development and usability of an online tool to enable stakeholders to design, analyse or modify a newborn hearing screening (NHS) programme. DESIGN: Data from literature, from existing NHS programmes, and observations by users were used to develop and refine the tool. Required inputs include prevalence of the hearing impairment, test sequence and its timing, attendance, sensitivity, and specificity of each screening step. Outputs include the number of cases detected and the costs of screening and diagnostics. STUDY SAMPLE: Eleven NHS programmes with reliable data. RESULTS: Three analyses are presented, exploring the effect of low attendance, number of screening steps, testing in the maternity ward, or screening at a later age, on the benefits and costs of the programme. Knowledge of the epidemiology of a staged screening programme is crucial when using the tool. CONCLUSIONS: This study presents a tool intended to aid stakeholders to design a new or analyse an existing hearing screening programme in terms of benefits and costs.

Supervised dichoptic gaming versus monitored occlusion therapy for childhood amblyopia: Effectiveness and efficiency.

PURPOSE: To compare the effectiveness and efficiency of supervised dichoptic action-videogame play to occlusion therapy in children with amblyopia. METHODS: Newly diagnosed children with amblyopia aged 4-12 years were recruited, excluding strabismus >30PD. After 16 weeks of refractive adaptation children were randomized to gaming 1 h/week supervised by the researcher, or electronically monitored occlusion 2 h/day. The gaming group played a dichoptic action-videogame using virtual reality goggles, which included the task of catching a snowflake presented intermittently to the amblyopic eye. Contrast for the fellow eye was self-adjusted until 2 identical images were perceived. The primary outcome was visual acuity (VA) change from baseline to 24 weeks. RESULTS: We recruited 96 children, 29 declined and 2 were excluded for language or legal issues. After refractive adaptation, 24 of the remaining 65 no longer met the inclusion criteria for amblyopia, and 8 dropped out. Of 16 children treated with gaming, 7 (6.7 years) completed treatment, whereas 9 younger children (5.3 years) did not. Of 17 treated with occlusion, 14 (5.1 years) completed treatment and 3 (4.5 years) did not. Of 5 children with small-angle strabismus, 3 treated with occlusion completed treatment and 2 treated with gaming did not. Median VA improved by 0.30 logMAR (IQR 0.20-0.40) after gaming, 0.20 logMAR (0.00-0.30) after occlusion (p = 0.823). Treatment efficiency was 1.25 logMAR/100 h (range 0.42-2.08) with gaming, 0.08 (-0.19-0.68) with occlusion (p < 0.001). CONCLUSION: Dichoptic gaming seems a viable alternative for older children with refractive amblyopia after glasses adaptation. Treatment efficiency with gaming under continuous supervision was 15 times higher than with occlusion at home.

A population-level post-screening treatment cost framework to help inform vision screening choices for children under the age of seven.

PURPOSE/BACKGROUND: Visual acuity (VA) screening in children primarily detects low VA and amblyopia between 3 and 6 years of age. Photoscreening is a low-cost, lower-expertise alternative which can be carried out on younger children and looks instead for refractive amblyopia risk factors so that early glasses may prevent or mitigate the conditions. The long-term benefits and costs of providing many children with glasses in an attempt to avoid development of amblyopia for some of them needs clarification. This paper presents a framework for modeling potential post-referral costs of different screening models once referred children reach specialist services. METHODS: The EUSCREEN Screening Cost-Effectiveness Model was used together with published literature to estimate referral rates and case mix of referrals from different screening modalities (photoscreening and VA screening at 2, 3-4 years and 4-5 years). UK 2019-20 published National Health Service (NHS) costings were used across all scenarios to model the comparative post-referral costs to the point of discharge from specialist services. Potential costs were compared between a) orthoptist, b) state funded ophthalmologist and c) private ophthalmologist care. RESULTS: Earlier VA screening and photoscreening yield higher numbers of referrals because of lower sensitivity and specificity for disease, and a different case mix, compared to later VA screening. Photoscreening referrals are a mixture of reduced VA caused by amblyopia and refractive error, and children with amblyopia risk factors, most of which are treated with glasses. Costs relate mainly to the secondary care providers and the number of visits per child. Treatment by an ophthalmologist of a referral at 2 years of age can be more than x10 more expensive than an orthoptist service receiving referrals at 5 years, but outcomes can still be good from referrals aged 5. CONCLUSIONS: All children should be screened for amblyopia and low vision before the age of 6. Very early detection of amblyopia refractive risk factors may prevent or mitigate amblyopia for some affected children, but population-level outcomes from a single high-quality VA screening at 4-5 years can also be very good. Total patient-journey costs incurred by earlier detection and treatment are much higher than if screening is carried out later because younger children need more professional input before discharge, so early screening is less cost-effective in the long term. Population coverage, local healthcare models, local case-mix, public health awareness, training, data monitoring and audit are critical factors to consider when planning, evaluating, or changing any screening programme.

Implementation of Newborn Hearing Screening in Albania.

Newborn hearing screening (NHS) was implemented in Albania in four maternity hospitals in 2018 and 2019. Implementation outcome, screening outcome, and screening quality measures were evaluated. Infants were first screened by midwives and nurses before discharge from the maternity hospital and returned for follow-up screening. Acceptability, appropriateness, feasibility, adoption, fidelity, coverage, attendance, and stepwise and final-referral rates were assessed by onsite observations, interviews, questionnaires, and a screening database. A post hoc analysis was performed to identify reasons for loss to follow up (LTFU) in a multivariate logistic regression. In total, 22,818 infants were born, of which 96.6% were screened. For the second screening step, 33.6% of infants were LTFU, 40.4% for the third, and 35.8% for diagnostic assessment. Twenty-two (0.1%) were diagnosed with hearing loss of ≥40 dB, six unilateral. NHS was appropriate and feasible: most infants are born in maternity hospitals, hence nurses and midwives could perform screening, and screening rooms and logistic support were supplied. Adoption among screeners was good. Referral rates decreased steadily, reflecting increasing skill. Occasionally, screening was repeated during a screening step, contrary to the protocol. NHS in Albania was implemented successfully, though LTFU was high. It is important to have effective data tracking and supervision throughout the screening.

The cost-effectiveness of different visual acuity screening strategies in three European countries: A microsimulation study.

Childhood vision screening programmes in Europe differ by age, frequency and location at which the child is screened, and by the professional who performs the test. The aim of this study is to compare the cost-effectiveness for three countries with different health care structures. We developed a microsimulation model of amblyopia. The natural history parameters were calibrated to a Dutch observational study. Sensitivity, specificity, attendance, lost to follow-up and costs in the three countries were based on the EUSCREEN Survey. Quality adjusted life-years (QALYs) were calculated using assumed utility loss for unilateral persistent amblyopia (1%) and bilateral visual impairment (8%). We calculated the cost-effectiveness of screening (with 3.5% annual discount) by visual acuity measurement at age 5 years or 4 and 5 years in the Netherlands by nurses in child healthcare centres, in England and Wales by orthoptists in schools and in Romania by urban kindergarten nurses. We compared screening at various ages and with various frequencies. Assuming an amblyopia prevalence of 36 per 1,000 children, the model predicted that 7.2 cases of persistent amblyopia were prevented in the Netherlands, 6.6 in England and Wales and 4.5 in Romania. The cost-effectiveness was €24,159, €19,981 and €23,589, per QALY gained respectively, compared with no screening. Costs/QALY was influenced most by assumed utility loss of unilateral persistent amblyopia. For all three countries, screening at age 5, or age 4 and 5 years were optimal. Despite differences in health care structure, vision screening by visual acuity measurement seemed cost-effective in all three countries.

Quality of life during occlusion therapy for amblyopia from the perspective of the children and from that of their parents, as proxy.

BACKGROUND: Parents pity their amblyopic child when they think that they suffer from occlusion therapy. We measured health-related quality of life during occlusion therapy. METHODS: We developed the Amblyopia Parents and Children Occlusion Questionnaire (APCOQ). It was designed by a focus group of patients, orthoptists and ophthalmologists and consisted of twelve items concerning skin contact of patch, activities, contact with other children, emotions and awareness of necessity to patch. Parents filled out the Proxy Version shortly before the Child Version was obtained from their child. Child Version item scores were compared with Proxy Version item scores and related to the child's age, visual acuity, refraction, angle of strabismus, and cause of amblyopia. RESULTS: 63 children were recruited by orthoptists, and their parents agreed to participate. Three children were excluded: one child with Down-syndrome, one child with cerebral palsy, and one child who had been treated by occlusion therapy. Included were 60 children (mean age 4.57 ± 1.34 SD) and 56 parents. Children had occluded 128 ± 45 SD days at interview. Prior to occlusion, 54 children had worn glasses. Cronbach's α was 0.74 for the Child Version and 0.76 for the Proxy Version. Children judged their quality of life better than their parents did, especially pertaining to skin contact and activities like games and watching TV. Notably, 13 children with initial visual acuity ≥ 0.6 logMAR in the amblyopic eye experienced little trouble with games during occlusion. Quality of life in eight children with strabismus of five years and older correlated negatively (Spearman rank mean rho = -0.43) with angle of strabismus. Children with amblyopia due to both refractive error and strabismus (n = 14) had, relatively, lowest quality of life, also according to their parents, as proxy. Several children did not know why they wore a patch, contrary to what their parents thought. CONCLUSIONS: Children's quality of life during occlusion therapy is affected less than their parents think, especially regarding skin contact, playing games and watching TV during occlusion. Quality of life correlates negatively with the angle of strabismus in children five years and older. Children do not know why they wear a patch, contrary to what their parents think. Notably, children with low visual acuity in the amblyopic eye, had little difficulty playing games.

Barriers to successful dichoptic treatment for amblyopia in young children.

PURPOSE: In an ongoing randomised clinical trial comparing dichoptic VR video games with patching for amblyopia, we evaluated any potential barriers to successful use of this novel amblyopia treatment method. METHODS: From December 2017, all newly diagnosed amblyopic children were recruited. Excluded were children under age 4 and patients with strabismus exceeding 30PD. The video game was played for 1 h per week at the outpatient clinic under direct supervision. Records were kept of difficulties encountered during treatment and categorised into domains. Factors influencing the successful completion of this treatment were identified and related to patient characteristics. RESULTS: Ninety-one children were recruited for the trial, 20 parents refused participation before randomisation, because of the logistical challenges the outpatient dichoptic treatment would cause them. Of the 17 children who commenced dichoptic treatment (median age 6.2 years; IQR 4.9-8.4 years), 10 did not complete treatment. Children under age 5.5 years were unable to comprehend the game settings or the game itself. Older children (N = 7; 41%) were less willing to comply with the video game. Loss of interest in the game (N = 8; 47%) was found to be a limiting factor at all ages. CONCLUSION: Half of the children failed to complete VR dichoptic treatment, mainly due to young age. In countries with nationwide screening where amblyopia is detected before age 6, the applicability of such dichoptic treatment is limited.

Assessment of hearing screening programmes across 47 countries or regions III: provision of childhood hearing screening after the newborn period.

OBJECTIVE: To inventory provision and features of childhood hearing screening after the newborn period (CHS), primarily in Europe. DESIGN: From each participating country or region, experts provided information through an extensive questionnaire: implementation year, age at screening, test method, pass criteria, screening location, screener profession, and quality indicators: coverage, referral, follow-up and detection rates, supplemented by literature sources. STUDY SAMPLE: Forty-two European countries or regions, plus Russia, Malawi, Rwanda, India, and China. RESULTS: CHS was performed universally with pure-tone audiometry screening (PTS) in 17 countries or regions, whereas non-universal CHS was performed in eight with PTS or whisper tests. All participating countries with universal PTS had newborn hearing screening. Coverage rate was provided from three countries, detection rate from one, and referral and follow-up rate from two. In four countries, universal PTS was performed at two ages. Earliest universal PTS was performed in a (pre)school setting by nurses (n = 9, median age: 5 years, range: 3-7), in a healthcare setting by doctors and nurses (n = 7, median age: 4.5 years, range: 4-7), or in both (n = 1). CONCLUSIONS: Within universal CHS, PTS was mostly performed at 4-6 years by nurses. Insufficient collection of data and monitoring with quality indicators impedes evaluation of screening.

Assessment of hearing screening programmes across 47 countries or regions II: coverage, referral, follow-up and detection rates from newborn hearing screening.

OBJECTIVES: To assess the performance of newborn hearing screening (NHS) programmes, through selected quality measures and their relationship to protocol design. DESIGN: NHS coverage, referral, follow-up and detection rates were aggregated. Referral rates were compared to age at screening step 1, number of steps, and test method: OAE or aABR. STUDY SAMPLE: A questionnaire on existing hearing screening was completed by experts from countries in Europe, plus Russia, Malawi, Rwanda, India and China. RESULTS: Out of 47 countries or regions, NHS coverage rates were reported from 26, referral rates from 23, follow up from 12 and detection rates from 13. Median coverage rate for step 1 was 96%. Referral rate from step 1 was 6-22% where screening may be performed <24 h from birth, 2-15% for >24 h, and 4% for >72 h. Referral rates to diagnostic assessment averaged 2.1% after one to two steps using OAE only, 1.7% after two steps including aABR, and 0.8% after three to four steps including aABR. Median detection rate for bilateral permanent hearing impairment ≥40dB was 1 per 1000 infants. CONCLUSION: Referral rates were related to age, test method and number of screening steps. Quality measures were not available for many NHS programmes.

Assessment of hearing screening programmes across 47 countries or regions I: provision of newborn hearing screening.

OBJECTIVES: Newborn hearing screening (NHS) varies regarding number and type of tests, location, age, professionals and funding. We compared the provision of existing screening programmes. DESIGN: A questionnaire containing nine domains: demography, administration, existing screening, coverage, tests, diagnosis, treatment, cost and adverse effects, was presented to hearing screening experts. Responses were verified. Clusters were identified based on number of screening steps and use of OAE or aABR, either for all infants or for well and high-risk infants (dual-protocol). STUDY SAMPLE: Fifty-two experts completed the questionnaire sufficiently: 40 European countries, Russia, Malawi, Rwanda, India and China. RESULTS: It took considerable effort to find experts for all countries with sufficient time and knowledge. Data essential for evaluation are often not collected. Infants are first screened in maternity wards in most countries. Human development index and health expenditure were high among countries with dual protocols, three screening steps, including aABR, and low among countries without NHS and countries using OAE for all infants. Nationwide implementation of NHS took 6 years, on average. CONCLUSION: The extent and complexity of NHS programmes are primarily related to health expenditure and HDI. Data collection should be improved to facilitate comparison of NHS programmes across borders.

Long-term follow-up of an amblyopia treatment study: change in visual acuity 15 years after occlusion therapy.

PURPOSE: To determine change in visual acuity (VA) in the population of a previous amblyopia treatment study (Loudon 2006) and assess risk factors for VA decrease. METHODS: Subjects treated between 2001 and 2003 were contacted between December 2015 and July 2017. Orthoptic examination was conducted under controlled circumstances and included subjective refraction, best corrected VA, reading acuity, binocular vision, retinal fixation, cover-uncover and alternating cover test. As a measure for degree of amblyopia, InterOcular VA Difference (IOD) at the end of occlusion therapy was compared with IOD at the follow-up examination using Wilcoxon's signed-rank test. Regression analysis was conducted to determine the influence of clinical and socio-economic factors on changes in IOD. RESULTS: Out of 303 subjects from the original study, 208 were contacted successfully, 59 refused and 15 were excluded because of non-amblyopic cause of visual impairment. Mean IOD at end of therapy (mean age 6.4 years) was 0.11 ± 0.16 logMAR, and IOD at follow-up examination (mean age 18.3 years) was 0.09 ± 0.21 logMAR; this difference was not significant (p = 0.054). Degree of anisometropia (p = 0.008; univariable analysis), increasing anisometropia (p = 0.009; multivariable), eccentric fixation (p < 0.001; univariable and multivariable); large IOD (p < 0.001; univariable and multivariable) and non-compliance during therapy (p = 0.028; univariable) were associated with IOD increase. CONCLUSION: Long-term results of occlusion therapy were good. High or increasing anisometropia, eccentric fixation and non-compliance during occlusion therapy were associated with long-term VA decrease. Subjects with poor initial VA had a larger increase despite little patching, but often showed long-term VA decrease.

Increase in treatment of retinopathy of prematurity in the Netherlands from 2010 to 2017.

PURPOSE: Compare patients treated for Retinopathy of Prematurity (ROP) in two consecutive periods. METHODS: Retrospective inventory of anonymized neonatal and ophthalmological data of all patients treated for ROP from 2010 to 2017 in the Netherlands, subdivided in period (P)1: 1-1-2010 to 31-3-2013 and P2: 1-4-2013 to 31-12-2016. Treatment characteristics, adherence to early treatment for ROP (ETROP) criteria, outcome of treatment and changes in neonatal parameters and policy of care were compared. RESULTS: Overall 196 infants were included, 57 infants (113 eyes) in P1 and 139 (275 eyes) in P2, indicating a 2.1-fold increase in ROP treatment. No differences were found in mean gestational age (GA) (25.9 ± 1.7 versus 26.0 ± 1.7 weeks, p = 0.711), mean birth weight (791 ± 311 versus 764 ± 204 grams, p = 0.967) and other neonatal risk factors for ROP. In P2, the number of premature infants born <25 weeks increased by factor 1.23 and higher oxygen saturation levels were aimed at in most centres. At treatment decision, 59.6% (P1) versus 83.5% (P2) (p = 0.263) infants were classified as Type 1 ROP (ETROP classification). Infants were treated with laser photocoagulation (98 versus 96%) and intravitreal bevacizumab (2 versus 4%). Retreatment was necessary in 10 versus 21 (p = 0.160). Retinal detachment developed in 6 versus 13 infants (p = 0.791) of which 2 versus 6 bilateral (p = 0.599). CONCLUSION: In period 2, the number of infants treated according to the ETROP criteria (Type 1) increased, the number of ROP treatments, retinal detachments and retreatments doubled and the absolute number of retinal detachments increased. Neonatal data did not provide a decisive explanation, although changes in neonatal policy were reported.

Endophthalmitis after strabismus surgery: incidence and outcome in relation to age, operated eye muscle, surgical technique, scleral perforation and immune state.

PURPOSE: Identify risk factors for endophthalmitis after strabismus surgery (EASS) and relate these to incidence and outcome. METHODS: Ophthalmologists, who had operated, diagnosed or treated EASS, completed a case record form with 71 questions in six domains: Preoperative, Surgery, Perforation, Postoperative, Outcome and Experts' opinion. To estimate the age-specific incidence per number of strabismus operations in the Netherlands during 1994-2013, the age distribution of Dutch cases was compared with the age-specific rates of strabismus surgery in the Dutch Registry of Strabismus Operations and with population data. Exploratory data analysis was performed. The immune state was evaluated in six patients. Five enucleated eyes were studied histopathologically. RESULTS: None of the 26 patients (27 eyes with EASS) were between 9 and 65 years old, except for one patient with retinal haemorrhage followed by endophthalmitis. In the Netherlands during 1994-2013, the rate of EASS was approximately one per 11 000 strabismus operations, but one per 4300 for children aged 0-3 and one per 1000 for patients 65 and older. Endophthalmitis was diagnosed on postoperative day 1-4 in children aged 0-3. In all 15 children aged 0-5, the 16 affected eyes were phthisical, eviscerated or enucleated. The involved eye muscle had been recessed in 25 of 27 cases. It was a medial rectus in 15 of 16 children aged 0-6. It was a lateral (6), inferior (2) or medial (1) rectus in elderly. Scleral perforation went unnoticed in all children (no record in three) and in two of seven elderly (no record in two). Histopathology showed transscleral scarring compatible with scleral perforation in four patients but, in a two-year-old girl who had EASS together with a transient medial rectus palsy, the sclera underneath the former suture tract was not perforated but did contain the long posterior ciliary artery. CONCLUSIONS: Endophthalmitis after strabismus surgery (EASS) affects children and elderly, with a grave outcome in young children. It occurs after recession of the medial rectus muscle in children, and it may occur without scleral perforation. Age and perforation are key determinants that interact with other factors that determine the occurrence and fulminance of EASS.

Scope and costs of autorefraction and photoscreening for childhood amblyopia-a systematic narrative review in relation to the EUSCREEN project data.

BACKGROUND: Amblyopia screening can target reduced visual acuity (VA), its refractive risk factors, or both. VA testing is imprecise under 4 years of age, so automated risk-factor photoscreening appears an attractive option. This review considers photoscreening used in community services, focusing on costs, cost-effectiveness and scope of use, compared with EUSCREEN project Country Reports describing how photo- and automated screening is used internationally. METHODS: A systematic narrative review was carried out of all English language photoscreening literature to September 10th 2018, using publicly available search terms. Where costs were considered, a CASP economic evaluation checklist was used to assess data quality. RESULTS: Of 370 abstracts reviewed, 55 reported large-scale community photoscreening projects. Five addressed cost-effectiveness specifically, without original data. Photoscreening was a stand-alone, single, test event in 71% of projects. In contrast, 25 of 45 EUSCREEN Country Reports showed that if adopted, photoscreening often supplements other tests in established programmes and is rarely used as a stand-alone test. Reported costs varied widely and evidence of cost-effectiveness was sparse in the literature, or in international practice. Only eight (13%) papers compared the diagnostic accuracy or cost-effectiveness of photoscreening and VA testing, and when they did, cost-effectiveness of photoscreening compared unfavourably. DISCUSSION: Evidence that photoscreening reduces amblyopia or strabismus prevalence or improves overall outcomes is weak, as is evidence of cost-effectiveness, compared to later VA screening. Currently, the most cost-effective option seems to be a later, expert VA screening with the opportunity for a re-test before referral.

Implementation of a neonatal hearing screening programme in three provinces in Albania.

OBJECTIVES: The EUSCREEN study compares the cost-effectiveness of paediatric hearing screening programmes and aims to develop a cost-effectiveness model for this purpose. Alongside and informed by the development of the model, neonatal hearing screening (NHS) is implemented in Albania. We report on the first year. METHODS: An implementation plan was made addressing objectives, target population, screening protocol, screener training, screening devices, care pathways and follow up. NHS started January 1st, 2018 in four maternity hospitals: two in Tirana, one in Pogradec and one in Kukës, representing both urban and rural areas. OAE-OAE-aABR was used to screen well infants in maternity hospitals, whereas aABR-aABR was used in neonatal intensive care units and in mountainous Kukës for all infants. Screeners' uptake and attitudes towards screening and quality of screening were assessed by distributing questionnaires and visiting the maternity hospitals. The result of screening, diagnostics, follow up and entry into early intervention were registered in a database and monitored. RESULTS: Screeners were keen to improve their skills in screening and considered NHS valuable for Albanian health care. The number of "fail" outcomes after the first screen was high initially but decreased to less than 10% after eight months. In 2018, 11,507 infants were born in the four participating maternity hospitals, 10,925 (94.9%) of whom were screened in the first step. For 486 infants the result of screening was not registered. For the first screen, ten parents declined, eight infants died and one infant was discharged before screening could be performed. In 1115 (10.2%) infants the test either could not be performed or the threshold was not reached; 361 (32,4%) of these did not attend the second screen. For the third screen 31 (34.4%) out of 90 did not attend. Reasons given were: parents declined (124), lived too far from screening location (95), their infant died (11), had other health issues (7), or was screened in private clinic (17), no reason given (138). CONCLUSIONS: Implementation of NHS in Albania is feasible despite continuing challenges. Acceptance was high for the first screen. However, 32.4% of 1115 infants did not attend the second screen, after a "fail" outcome for the first test.

Prevalence of permanent neonatal hearing impairment: systematic review and Bayesian meta-analysis.

Objective: To investigate the variance in reported prevalence rates of permanent neonatal hearing impairment (HI) worldwide.Design: A systematic review and meta-analysis was performed on reported prevalence rates of sensorineural and permanent conductive or mixed HI worse than 40 dB in neonates, detected as a result of a screening programme or audiometric study.Study sample: For meta-analysis, 35 articles were selected, 25 from high-income countries and 10 from middle-income countries according to the world bank classification system.Results: The prevalence rate of permanent uni- and bilateral HI worse than 40 dB in neonates varied from 1 to 6 per 1000, the overall prevalence was 2.21 per 1000 [1.71, 2.8]. In NICU populations the prevalence rate was higher with a larger fraction of bilateral cases. Although not significant, prevalence rates were slightly higher in Asia compared to Europe and the number of infants lost to follow-up appeared higher in countries with lower gross national income.Conclusion: Substantial variations exist in prevalence rates of neonatal permanent HI across countries and regions. There is a strong need for more data from low-income countries to identify demographic factors that account for this variability in reported prevalence rates. Reporting these data in a uniform way is advocated.

Plusoptix photoscreener use for paediatric vision screening in Flanders and Iran.

PURPOSE: Photoscreening assesses risk factors for amblyopia, as an alternative to measurement of visual acuity (VA) to detect amblyopia, on the premise that its early correction could prevent development of amblyopia. We studied implementations of Plusoptix photoscreening in existing population-based screening in Flanders and Iran. METHODS: In Flanders, VA is measured at age 3, 4 and 6, photoscreening was added to existing screening at age 1 and 2.5 years in 2013. In Iran, VA is measured at ages 3-6 years, photoscreening was added at ages 3-6 years between 2011 and 2016. Plusoptix use was analysed in the literature for detection of risk factors for amblyopia and amblyopia itself, for ages 0-3 and for 4-6. A questionnaire, containing seven domains: existing vision screening, addition of photoscreening, implementation in screening program, training, attendance, diagnosis and treatment, and costs was distributed. In Iran, screening procedures were observed on site. RESULTS: Implementation of Plusoptix photoscreening was mainly analysed from questionnaires and interviews, its effectiveness from literature data. In Flanders, of 56 759 children photoscreened at age one (81% of children born in 2013), 9.2% had been referred, 13% of these were treated, mostly with glasses, resulting in an increase of 4-year-old children wearing glasses from 4.7% to 6.4%. In Iran, 90% of children aged 3-6 years participated in vision screening in 2016, but only those who failed the vision test were subjected to photoscreening. CONCLUSIONS: In Flanders, the use of Plusoptix photoscreening at ages 1 and 2.5 resulted in an increase of children wearing glasses, but it remains unknown how many cases of amblyopia have been prevented. Studies are needed to determine the relation between size and sort of refractive error and strabismus, and the increased chance to develop amblyopia.

Nystagmus in patients with congenital stationary night blindness (CSNB) originates from synchronously firing retinal ganglion cells.

Congenital nystagmus, involuntary oscillating small eye movements, is commonly thought to originate from aberrant interactions between brainstem nuclei and foveal cortical pathways. Here, we investigated whether nystagmus associated with congenital stationary night blindness (CSNB) results from primary deficits in the retina. We found that CSNB patients as well as an animal model (nob mice), both of which lacked functional nyctalopin protein (NYX, nyx) in ON bipolar cells (BCs) at their synapse with photoreceptors, showed oscillating eye movements at a frequency of 4-7 Hz. nob ON direction-selective ganglion cells (DSGCs), which detect global motion and project to the accessory optic system (AOS), oscillated with the same frequency as their eyes. In the dark, individual ganglion cells (GCs) oscillated asynchronously, but their oscillations became synchronized by light stimulation. Likewise, both patient and nob mice oscillating eye movements were only present in the light when contrast was present. Retinal pharmacological and genetic manipulations that blocked nob GC oscillations also eliminated their oscillating eye movements, and retinal pharmacological manipulations that reduced the oscillation frequency of nob GCs also reduced the oscillation frequency of their eye movements. We conclude that, in nob mice, synchronized oscillations of retinal GCs, most likely the ON-DCGCs, cause nystagmus with properties similar to those associated with CSNB in humans. These results show that the nob mouse is the first animal model for a form of congenital nystagmus, paving the way for development of therapeutic strategies.

High rate of failed visual-acuity measurements with the Amsterdam Picture Chart in screening at the age of 36 months.

PURPOSE: In the Netherlands, youth health care physicians and nurses screen all children for general health disorders at Child Health Care Centers. As part of this, the eyes are screened seven times, with the first visual acuity (VA) measurement at 36 months with the Amsterdam Picture Chart (APK). The suitability of the APK has been questioned. METHODS: Children born between July 2011 and June 2012 born in the provinces Drenthe, Gelderland and Flevoland and invited for screening at 36 months were eligible. Parents were sent the APK picture optotypes to practise with their children in advance. Data were collected from electronic screening records. The Dutch vision screening guideline prescribes that children with VA <5/6, or one line interocular difference (not logMAR, however) should be retested or referred. RESULTS: Of 10 809 eligible children, 1546 did not attend and 602 attended but had no VA measurement at age 36 months, 247 of these were under orthoptic treatment. Of the 8448 children examined, VA was sufficient in 5663 (67.0%) and insufficient in 1312 (15.5%). In 1400 (16.6%), the measurement of VA itself failed. In 73 (0.9%), data were missing. Of the 216 children with 2 failed VA measurements, 150 (69%) were not referred, and measurement of VA was deferred to the next general screening examination at 45 months. CONCLUSION: Although most parents had practised the APK picture optotypes at home with their children, the rate of failed APK measurements plus the measurements with insufficient VA was 32.1% at 36 months. Similar rates have previously been reported for Lea Symbols and HOTV, permitting the conclusion that measurement of VA at the age of 36 months cannot be recommended as a screening test in the general population.