Strabismus controversies that inspired the foundation of the Donders Society for Strabology and of the journal Strabismus.

The Donders Society for Strabology and the journal Strabismus were founded in 1984 and 1992 to (i) stimulate scientific exchange, (ii) bridge the gap between clinical strabismus and neurophysiology by covering the two fields in a single journal and (iii) provide a forum for multicenter studies. They were inspired by two controversies on the treatment of strabismus, whether accommodative esotropia should be treated with glasses or not and whether infantile esotropia should be operated in the first years of life to preserve or reinstate binocular vision. Key assumptions in the theory leading to the former controversy were that the angle between the oblique muscle plane and the sagittal plane was small in strabismus patients causing excyclotropia, that hemiretinal suppression occurred when the left and right halves of the visual fields were no longer aligned because of excyclotropia and that binasal or bitemporal suppression disturbed the balance of the optomotor reflexes and thereby caused esotropia or exotropia. Hemiretinal suppression also disturbed accommodation related to the development of hyperopia, which did not cause esotropia and could worsen by wearing glasses. The Donders Society for Strabismology was founded in 1984, and expanded with Flemish pediatric ophthalmologists and orthoptists two years later. A survey gauging the need for a European journal on strabismus and amblyopia in 1985 got favorable responses from strabismologists from continental Europe. However, a proposal by Aeolus Press to the European Strabismological Association to adopt or endorse such journal was turned down in 1989 and by the International Strabismological Association in 1990. In 1992 candidate editors were invited to start the journal Strabismus without adoption by a professional organization and founding meetings took place in April and May, 1992. Regarding the three goals set, it can be said that both the Donders Society for Strabology and the journal Strabismus have stimulated scientific exchange to a high degree, but they have bridged the gap between clinical strabismus and neurophysiology only modestly. Strabismus did successfully provide a forum for the multicenter Early vs. Late Infantile Strabismus Surgery Study.

Acceptability of childhood screening: a systematic narrative review.

OBJECTIVES: A systematic narrative literature review was undertaken to assess the acceptability of childhood screening interventions to identify factors to consider when planning or modifying childhood screening programs to maximize participation and uptake. STUDY DESIGN: This is a systematic narrative literature review. METHODS: Electronic databases were searched (MEDLINE, EMBASE, PsycINFO via Ovid, CINAHL, and Cochrane Library) to identify primary research studies that assessed screening acceptability. Studies were categorized using an existing theoretical framework of acceptability consisting of seven constructs: affective attitude, burden, ethicality, intervention coherence, opportunity costs, perceived effectiveness, and self-efficacy. A protocol was developed and registered with PROSPERO (registration no. CRD42018099763) RESULTS: The search identified 4529 studies, and 46 studies met the inclusion criteria. Most studies involved neonatal screening. Programs identified included newborn blood spot screening (n = 22), neonatal hearing screening (n = 13), Duchenne muscular dystrophy screening (n = 4), cystic fibrosis screening (n = 3), screening for congenital heart defects (n = 2), and others (n = 2). Most studies assessed more than one construct of acceptability. The most common constructs identified were affective attitude (how a parent feels about the program) and intervention coherence (parental understanding of the program, and/or the potential consequences of a confirmed diagnosis). CONCLUSIONS: The main acceptability component identified related to parental knowledge and understanding of the screening process, the testing procedure(s), and consent. The emotional impact of childhood screening mostly explored maternal anxiety. Further studies are needed to examine the acceptability of childhood screening across the wider family unit. When planning new (or refining existing) childhood screening programs, it is important to assess acceptability before implementation. This should include assessment of important issues such as information needs, timing of information, and when and where the screening should occur.

The history of the Ostschweizerische Pleoptik und Orthoptik Schule in St. Gallen.

In judging the achievements of Alfred Bangerter in treatment and research of amblyopia it is easy to conclude that his pleoptic exercises have been forgotten because occlusion therapy is more effective and cheaper. However, Bangerter introduced the visuscope to determine the point of fixation directly on the retina, he started the first "school" (exercise treatment facility) for pleoptics and orthoptics in St. Gallen only 18 years after Mary Maddox did so in London and he started a training program for orthoptists. In 1957 the Genossenschaft Ostschweizerische Pleoptik-und Orthoptik-Schule, the OPOS Society, was founded, that in the following years built a clinic especially for the treatment of amblyopia. The idea was to treat children not in a clinic but in a home for children that offered optimal treatment but also adequate lodging and care for the children with amblyopia. The Cantonal government contributed by donating a right to build on the premises of the Cantonal Hospital. The new OPOS Clinic measured more than 500 square meters, had 4 floors and a cellar, and contained outpatient treatment facilities, two operating theatres, patient bedrooms, pleoptic and orthoptic exercise rooms with many devices and classrooms for orthoptic students. There were 56 beds for children. After Bangerter retired as chief physician of the Eye Clinic in 1974, he continued and expanded his clinical and surgical activity in the OPOS Clinic next to the Eye Clinic. After his successor in the OPOS Clinic retired in 1987, the OPOS Foundation sold the OPOS Clinic to the Canton that reintegrated it into the Eye Clinic. In the meantime, Bangerter had continued to pursue his ideal of amblyopia treatment and built a new clinic in Heiden in the neighbouring Canton Appenzell Ausserrhoden, for pleoptics, orthoptics, strabismus surgery, plastic eye surgery, but also for controversial treatments for macular degeneration and other retinal disorders. This Rosenberg Clinic opened in 1982 but Bangerter already stepped down in April 1983 and opened a day clinic in the Rosenbergstrasse in St. Gallen some years later instead. Strangely enough, one of the reasons he had moved to the Rosenberg Clinic was that he insisted on lengthy clinical stays for the treatment of amblyopia, but exactly that was one of the main causes of financial problems.

Why did Donders, after describing pseudotorsion, deny the existence of ocular counterrolling together with Ruete, Volkmann, von Graefe and von Helmholtz, until Javal reconfirmed its existence?

After the rapid spread of strabismus surgery by total tenotomy, which had been proposed by the orthopedist Louis Stromeyer from Göttingen in 1838 and performed by the plastic surgeon Johann Friedrich Dieffenbach on October 26th and by the ophthalmologist Florent Cunier on October 29th, 1839, brilliant researchers studied the physiology of eye movements, resulting in the laws by Franciscus Cornelis Donders on pseudotorsion in tertiary positions of gaze and by Johann Benedict Listing that each eye position can be reached by rotation about an axis perpendicular to the primary and the new position of gaze. John Hunter had first described ocular counterrolling (OCR) with head tilt in 1786. The anatomist Alexander Friedrich von Hueck inferred from anatomical studies, however, that up to 28.6° OCR would be possible onhead-tilt to right or left shoulder in 1838, and estimated his own OCR seen in a mirror at approximately 25°. Donders, Christian Georg Theodor Ruete, Alfred Wilhelm Volkmann, Albrecht von Graefe and Hermann von Helmholtz subsequently denied the existence of OCR for many years and thought that only pseudotorsion existed. Louis Emile Javal had myopia and astigmatism, and he re-established the existence of OCR in 1867 when he noticed that, on head tilt to either shoulder, the axis of astigmatism of his eyes no longer coincided with the axis of astigmatism of his glasses.

The effect of omitting an early population-based vision screen in the Netherlands: A micro-simulation model approach.

Objective To estimate the effect of omitting an individual screen from a child vision screening programme on the detection of amblyopia in the Netherlands. A previous study (Rotterdam Amblyopia Screening Effectiveness Study) suggested that the three screens carried out between 6 and 24 months contributed little. Methods We developed a micro-simulation model that approximated the birth-cohort data from the previous study, in which 2964 children had completed follow-up at age 7, and 100 amblyopia cases were detected. Detailed data on screens, referrals, and orthoptic follow-up, including the cause of amblyopia, were available. The model predicted the number of amblyopia cases detected for each screen and for the entire screening programme, and the effect of omitting screens. Incidence curves for all types of amblyopia caused by strabismus, refractive anomalies or by both were estimated by approximation of the observational data, in conjunction with experts' estimations and the literature. Results We calculated mean actual sensitivity per screen per type of amblyopia, and the effect per screen. Screening at 24 months was found to be least effective. The impact on the screening programme, estimated by summing the effectiveness per screen, omitting the 24-month screen, was a reduction of 3.4% (57 vs. 59 cases) in the number of detected cases of amblyopia at age 5. Conclusion The effectiveness of the Dutch vision screening programme would hardly be affected by omission of the 24-month screening examination. A disinvestment study is warranted.

Implementation of an Educational Cartoon ("the Patchbook") and Other Compliance-Enhancing Measures by Orthoptists in Occlusion Treatment of Amblyopia.

PURPOSE: This implementation study evaluated orthoptists' use of an educational cartoon ("the Patchbook") and other measures to improve compliance with occlusion therapy for amblyopia. METHODS: Participating orthoptists provided standard orthoptic care for one year, adding the Patchbook in the second year. They attended courses on compliance and intercultural communication by communication skills training. Many other compliance-enhancing measures were initiated. Orthoptists' awareness, attitude, and activities regarding noncompliance were assessed through interviews, questionnaires, and observations. Their use of the Patchbook was measured. The study was performed in low socio-economic status (SES) areas and in other areas in the Netherlands. It was attempted to integrate education on compliance into basic and continuing orthoptic training. RESULTS: The Patchbook was used by all 9 orthoptists who participated in low-SES areas and 17 of 23 orthoptists in other areas. Courses changed awareness and attitude about compliance, but this was not sustained. Although orthoptists estimated compliance during patching at 70%, three-quarters never suspected noncompliance during a full day of observation in any of their patients. Explanations to parents who spoke Dutch poorly were short. In the second year, explanations to children were longer. Implementation of all 7 additional compliance-enhancing measures failed. Education on compliance was not integrated into orthoptists' training. CONCLUSION: Almost all orthoptists used the Patchbook and, as another study demonstrated, it proved to be very effective, especially in low-SES areas. Duration of explanation was inversely proportional to parents' fluency in Dutch. Noncompliance was rarely suspected by orthoptists. Although 7 additional compliance-enhancing measures had been conceived and planned with the best intentions, they were not realized. These required extra, unpaid time from the orthoptists, which is especially scarce in hospitals in low-SES areas where the educational cartoon is most needed.

Comparison of optotypes of Amsterdam Picture Chart with those of Tumbling-E, LEA symbols, ETDRS, and Landolt-C in non-amblyopic and amblyopic patients.

PURPOSE: To compare optotypes of the Amsterdam Picture Chart (APK) with those of Landolt-C (LC), Tumbling-E (TE), ETDRS and LEA symbols (LEA), to assess their reliability in measuring visual acuity (VA). METHODS: We recruited healthy controls with equal VA and amblyopes with ≥2 LogMAR lines interocular difference. New logarithmic charts were developed with LC, TE, ETDRS, LEA, and APK with identical size and spacing (four optotypes) between optotypes. Charts were randomly presented at 5 m under DIN EN ISO 8596 and 8597 conditions. VA was measured with LC (LC-VA), TE, ETDRS, LEA, and APK, using six out of ten optotypes answered correctly as threshold. RESULTS: In 100 controls aged 17-31, LC-VA was -0.207 ± SD 0.089 LogMAR. Visual acuity measured with TE differed from LC-VA by 0.021 (positive value meaning less recognizable), with ETDRS 0.012, with Lea 0.054, and with APK 0.117. In 46 amblyopic eyes with LC-VA <0.5 LogMAR, the difference was for TE 0.017, for ETDRS 0.017, for LEA 0.089, and for APK 0.213. In 13 amblyopic eyes with LC-VA ≥0.5 LogMAR, the difference was for TE 0.122, ETDRS 0.047, LEA 0.057, and APK 0.019. APK optotypes had a lower percentage of passed subjects at each LogMAR line compared to Landolt-C. The 11 APK optotypes had different thresholds. CONCLUSIONS: Small APK optotypes were recognized worse than all other optotypes, probably because of their thinner lines. Large APK optotypes were recognized relatively well, possibly reflecting recognition acuity. Differences between the thresholds of the 11 APK optotypes reduced its sensitivity further.

Outcome and quality of screening in a nationwide survey on retinopathy of prematurity in The Netherlands.

PURPOSE: Provide insight in natural history, screening and treatment policy of retinopathy of prematurity (ROP) in The Netherlands. METHODS: A multicentre, prospective, population-based study (NEDROP) included all preterm infants born in 2009 in The Netherlands fulfilling the inclusion criteria for ROP screening. Anonymised data from ophthalmologists, neonatologists and paediatricians were merged on identification number. RESULTS: Of 2033 reported infants, 1688 (83%) were screened for ROP. ROP stage was reported in 100%, zone in 94.4% and plus disease in 83%. ROP developed in 324 (19.2%), mild ROP (stage 1-2) in 294 (17.4%), severe ROP (stage 3 or more) in 30 (1.8%) and 17 (1%) were treated. The initial screening examination was not performed within the required 42 days in 641 (38%). Date for follow-up was recorded 1973 times and accomplished within 3 days from the planned date in 1957 (99.2%). The chance of not being screened increased from 12.9% without transfer to another hospital to 23.5, 18.5 and 25% after 1, 2, or 3 transfers, respectively. CONCLUSIONS: The incidence of severe ROP and infants treated was low. NEDROP emphasises that timing of initial examination and transfer to another hospital are issues of concern within the screening process.

Reduction in screening for retinopathy of prematurity through risk factor adjusted inclusion criteria.

AIMS: To develop a new national screening guideline for retinopathy of prematurity (ROP). METHODS: Included were infants of the 2009 prospective ROP inventory in The Netherlands with gestational age (GA) <32 weeks and/or birth weight (BW) <1500 g. Five models were studied, based on GA and BW in combination with no, one or a set of five risk factors for ROP. Risk factors were determined by logistic regression. In MEDLINE and EMBASE, additional risk factors were searched. A precondition was that no infants with severe ROP would be missed. Receiver operating characteristic curves or classical measures were used to determine diagnostic accuracy. RESULTS: The model including all infants with severe ROP comprised screening of infants with GA <30 weeks and/or BW <1250 g and a selection of infants with GA 30-32 weeks and/or BW 1250-1500 g, with at least one of the following risk factors: artificial ventilation (AV), sepsis, necrotising enterocolitis (NEC), postnatal glucocorticoids or cardiotonica. This model would not detect 4.8% (95% CI 2.5% to 8.0%) of infants with mild ROP and would reduce infants eligible for screening by 29%. CONCLUSIONS: In The Netherlands, screening may be safely reduced using a new guideline based on GA, BW, AV, sepsis, NEC, postnatal glucocorticoids and cardiotonica.

Randomised comparison of three tools for improving compliance with occlusion therapy: an educational cartoon story, a reward calendar, and an information leaflet for parents.

BACKGROUND: We previously demonstrated that compliance with occlusion therapy for amblyopia was improved by the use of an educational programme, especially in children of parents of foreign origin and who spoke Dutch poorly. The programme consisted of: (i) a cartoon story for amblyopic children that explained without words why they should patch, (ii) a calendar with reward stickers, and (iii) an information leaflet for parents. In the current study, we assessed the individual effect of each component on compliance. METHODS: We recruited 120 3- to 6-year-old children who lived in a low socio-economic status (SES) area in The Hague and were starting occlusion therapy for the first time. They were randomised to receive one of the components (three intervention groups), or a picture to colour (control group). The randomisation was blinded for treating orthoptist and researcher. Compliance was measured electronically using the Occlusion Dose Monitor (ODM). Primary outcome was percentage of compliance (actual/prescribed occlusion time). Secondary outcome was absolute occlusion hours per day. Parental fluency in Dutch was rated on a five-point scale. RESULTS: Compliance could be measured electronically in 88 of the 120 children; in 32 others, it failed for various reasons. Parental fluency in Dutch was moderate or worse in 36.4 % (p = 0.327). Average compliance was 55 % standard deviation (SD) 40 (n = 18) in the control group, 89 % SD 25 in the group receiving the educational cartoon (n = 25, P = 0.002 compared with control group), 67 % SD 33 (n = 24, P = 0.301) in the reward-calendar group and 73 % SD 40 (n = 21, P = 0.119) in the parent-information-leaflet group. On average, children in the control group occluded 1:46 SD1:19 hours/day, 2:33 SD 1:18 hours/day in the group receiving the educational cartoon, 1:59 SD 1:13 hours/day in the reward-calendar group and 2:18 SD 1:13 hours/day in the parent-information-leaflet group. No child who received the cartoon story occluded less than 1 hour per day, against seven in the reward-calendar group, five in the parent-information-leaflet group and five in the control group. CONCLUSIONS: Although all three components of the programme improved compliance with occlusion therapy in children in low-SES areas, the educational cartoon had the strongest effect, as it explained without words to a 4- to 5-year-old child why it should wear the eye patch.

Best age for surgery for infantile esotropia.

Infantile esotropia (IE) is defined as an esotropia before the age of 6 months, with a large angle, latent nystagmus, dissociated vertical deviation, limitation of abduction, and reduced binocular vision, without neurological disorder. Prematurity, low birth weight, and low Apgar scores are significant risk factors for IE. US standard age of first surgery is 12-18 months, in Europe 2-3 years. The only study to date with prospectively assigned early- and late-surgery groups and evaluation according to intention-to-treat, was the European Early vs. Late Infantile Strabismus Surgery Study (ELISSS). In that study 13.5% of children operated around 20 months vs. 3.9% (P = 0.001) of those operated around 49 months had gross stereopsis (Titmus Housefly) at age 6. The reoperation rate was 28.7% in children operated early vs. 24.6% in those operated late. Unexpectedly, 8% in the early group vs. 20% in the late group had not been operated at age 6, although all had been eligible for surgery at baseline at 11 SD 3.7 months. In most of these children the angle of strabismus decreased spontaneously. In a meta-regression analysis of the ELISSS and 12 other studies we found that reoperation rates were 60-80% for children first operated around age 1 and 25% for children operated around age 4. Based on these findings, the endpoints to consider when contemplating best age for surgery in an individual child with IE should be: (1) degree of binocular vision restored or retained, (2) postoperative angle and long-term stability of the angle and (3) number of operations needed or chance of spontaneous regression. IE is characterized by lack of binocular connections in the visual cortex that cannot develop, e.g. because the eyes squint, or do not develop, e.g. after perinatal hypoxia. As the cause of IE, whether motor or sensory, is a determinant of surgical outcome, a subdivision of IE according to cause is needed. As similarities exist between IE and cerebral palsy we propose to adapt the working definition formulated by the Surveillance of Cerebral Palsy in Europe and define IE as "a group of permanent, but not unchanging, disorders with strabismus and disability of fusional vergence and binocular vision, due to a nonprogressive interference, lesion, or maldevelopment of the immature brain, the orbit, the eyes, or its muscles, that can be differentiated according to location, extent, and timing of the period of development."

How Dutch orthoptists deal with noncompliance with occlusion therapy for amblyopia.

BACKGROUND: We previously found that compliance with occlusion therapy for amblyopia is poor, especially among children of non-native parents who spoke Dutch poorly and who were low educated. We investigated conception, awareness, attitude, and actions to deal with noncompliance among Dutch orthoptists. METHODS: Orthoptists working in non-native, low socioeconomic status (SES) areas and a selection of orthoptists working elsewhere in the Netherlands were studied. They were observed in their practice, received a structured questionnaire, and underwent a semi-structured interview. Finally, a short survey was sent to all working orthoptists in the Netherlands. RESULTS: Nine orthoptists working in non-native, low-SES areas and 23 working elsewhere in the Netherlands participated. One hundred and fifty-one orthoptists returned the short survey. Major discrepancies existed in conception, awareness, and attitude. Opinions differed on what should be defined as noncompliance and on what causes noncompliance. Some orthoptists found noncompliance annoying, unpleasant, and hard to imagine, others were more understanding. Many pitied the noncompliant child. Almost all thought that the success of occlusion therapy lies both with the parents and the orthoptist, but one third thought that noncompliance was not solely their responsibility. Patients' compliance was estimated at 69.3% in non-native, low-SES areas (electronically, 52% had been measured), at 74.1% by the other 23 orthoptists, and at 73.8% in the short survey. Actions to improve compliance were diverse; some increased occlusion hours whereas others decreased them. In non-native, low-SES areas, 22% spoke Dutch moderately to none; the allotted time for a patient's first visit was 21'; the time spent on explaining to the parents was 2'30" and to the child 10". In practices of the other 23 orthoptists, 6% spoke Dutch moderately to none (P<0.0001), the time for a patient's first visit was 27'24" (P=0.47), and the periods spent explaining were 2'51" (P=0.59) and 26" (P=0.17), respectively. CONCLUSION: Conception, awareness, attitude, and actions to deal with noncompliance varied among orthoptists. In non-native, low-SES areas, time spent on explanation was shorter, despite a lower fluency in Dutch among the parents.

Predictive value of age, angle, and refraction on rate of reoperation and rate of spontaneous resolution in infantile esotropia.

UNLABELLED: In the Early vs. Late Infantile Strabismus Surgery Study (ELISSS), 13.5% of children operated at 20 months vs. 3.9% of those operated at age 4 had gross binocular vision (Titmus Housefly). Reoperation rates were 28.7% in the former vs. 24.6% in the latter group and, although all were eligible for surgery at baseline at 11 SD 3.7 months, 8% in the early group vs. 20% in the late group were never operated, mostly because their angle decreased spontaneously. We assessed the predictive value of age, angle, and refraction in these matters. METHODS: The ELISSS reoperation rates were first compared with those found in nine series of consecutive cases in nine university clinics operated during one particular year, between 6 and 23 years previously. Logistic regression was used to estimate the effect of postoperative angle and clinic on the chance of reoperation. Secondly, a meta-regression analysis was done of these and other reported reoperation rates. The mean age at operation and the mean duration of follow-up were regressed on the logistically transformed reported reoperation rates. Finally, to estimate the chance of spontaneous decrease of the angle without surgery, a random-effects model was fitted on the 6-monthly orthoptic measurements of angle and refraction in the ELISSS that antedated surgery, loss to follow-up, or final examination. In the random-effects model (see online-only supplement link or visit, www.simonsz.net), for ELISSS patients the random effect was defined as the deviation of the average angle, the fixed effect. A vector was defined based on age and spherical equivalent of the patient. The variance around the prediction consisted of uncertainty in the estimations, random effects, and residuals. RESULTS: In the retrospective study, 204 patients who had been first operated between 6 and 23 years previously were eligible. A reoperation had been performed in 32 (19.3%) of the remaining 166 children who were 4.33 SD 1.35 years old at first surgery. The reoperation rate was 7.3% for those with a postoperative angle of -4° to +4° (N = 82), 25% for postoperative divergence > 5°, and 29% for postoperative convergence 10° to 14°. Strabismologists overestimated the reoperation rates at double. In the meta-regression analysis, 12 studies were included. Reoperation rates were between 60% and 80% for children first operated around age 1 and approximately 25% for children operated around age 4 (best fit: -0.221 Ln [age in months] + 1.1069; R(2) = 0.5725). Finally, in the predictions of random-effects model, a small angle at age 1 and hyperopia of approximately +4 increased the chance of spontaneous decrease of the angle into a microstrabismus. DISCUSSION: The benefit of early surgery for gross binocular vision is balanced by a higher reoperation rate and an occasional child being operated that would have had a spontaneous decrease into a microstrabismus without surgery. The fact that, in the ELISSS, hyperopia was associated with a decrease of the angle underscores the benefit of early refractive correction.

Nightblindness-associated transient tonic downgaze (NATTD) in infant boys with chin-up head posture.

Eleven infant boys presented with chin-up head posture, tonic downgaze and, on attempted upgaze, large-amplitude upward saccades with deceleration during the slow phase downward. The gaze-evoked upward saccades disappeared at the age of 2 or 3 years. In addition, they had high-frequency, small-amplitude horizontal pendular nystagmus that remained. Among these infant boys were 2 pairs of maternally related half-brothers, 2 cousins, and 2 siblings. Visual acuity ranged from 0.1 to 0.6, ERG-amplitudes (both A- and B-wave) were reduced, and severe myopia was found in 5 cases. Eight boys had CACNA1F mutations, and 1 boy had a NYX mutation, compatible with incomplete or complete congenital stationary nightblindness (iCSNB or cCSNB), respectively. This points to a defective synapse between the rod and the ON-bipolar cell causing the motility disorder: CACNA1F is located on the rod side of this synapse, whereas NYX is located on the side of the ON-bipolar cell. The coexistence of horizontal and vertical nystagmus has been previously described in dark-reared cats.

Psychological causes of non-compliance with electronically monitored occlusion therapy for amblyopia.

AIM: To analyse psychological causes for low compliance with occlusion therapy for amblyopia. METHOD: In a randomised trial, the effect of an educational programme on electronically measured compliance had been assessed. 149 families who participated in this trial completed a questionnaire based on the Protection Motivation Theory after 8 months of treatment. Families with compliance less than 20% of prescribed occlusion hours were interviewed to better understand their cause for non-compliance. RESULTS: Poor compliance was most strongly associated with a high degree of distress (p<0.001), followed by low perception of vulnerability (p = 0.014), increased stigma (p = 0.017) and logistical problems with treatment (p = 0.044). Of 44 families with electronically measured compliance less than 20%, 28 could be interviewed. The interviews confirmed that lack of knowledge, distress and logistical problems resulted in non-compliance. CONCLUSION: Poor parental knowledge, distress and difficulties implementing treatment seemed to be associated with non-compliance. For the same domains, the scores were more favourable for families who had received the educational programme than for those who had not.

A randomised comparison of bilateral recession versus unilateral recession-resection as surgery for infantile esotropia.

OBJECTIVE: Infantile esotropia, a common form of strabismus, is treated either by bilateral recession (BR) or by unilateral recession-resection (RR). Differences in degree of alignment achieved by these two procedures have not previously been examined in a randomised controlled trial. DESIGN: Controlled, randomised multicentre trial. SETTING: 12 university clinics. PARTICIPANTS AND INTERVENTION: 124 patients were randomly assigned to either BR or RR. Standardised protocol prescribed that the total relocation of the muscles, in millimetres, was calculated by dividing the preoperative latent angle of strabismus at distance, in degrees, by 1.6. MAIN OUTCOME MEASURE: Alignment assessed as the variation of the postoperative angle of strabismus during alternating cover. RESULTS: The mean preoperative latent angle of strabismus at distance fixation was +17.2 degrees (SD 4.4) for BR and +17.5 degrees (4.0) for RR. The mean postoperative angle of strabismus at distance was +2.3 degrees (5.1) for BR and +2.9 degrees (3.5) for RR (p = 0.46 for reduction in the angle and p = 0.22 for the within-group variation). The mean reduction in the angle of strabismus was 1.41 degrees (0.45) per millimetre of muscle relocation for RR and 1.47 (0.50) for BR (p = 0.50 for reduction in the angle). Alignment was associated with postoperative binocular vision (p = 0.001) in both groups. CONCLUSIONS: No statistically significant difference was found between BR and RR as surgery for infantile esotropia.