Prevalence and Risk Factors of Strabismus in a UK Multi-ethnic Birth Cohort

Nonsurgical Consecutive Exotropia Following Childhood Esotropia: A Multicentered Study

PURPOSE

Nonsurgical consecutive exotropia (NCX) occurs when an esotropia (ET) spontaneously converts to exotropia (XT) without surgical intervention. Although NCX is considered to occur in early-onset accommodative ET with high hyperopia, consensus on causation is lacking. We report the clinical characteristics of NCX and assess the response to conservative management.

DESIGN

Retrospective, multicenter, observational case series.

METHODS

Patients aged 6 months and older with an initial diagnosis of ET who converted to XT without surgical intervention. Sensory strabismus was excluded. Age, visual acuity, cycloplegic refraction, glasses prescriptions, deviation, and binocular vision were collected.

RESULTS

Forty-nine children were included with a mean age of 3.5 ± 1.6 years and 8.4 ± 3.6 years at the time of ET and NCX, respectively. Mean refractive error was +4.40 ± 2.13 diopters (D) and +4.05 ± 2.74 D at the time of ET and NCX, respectively. Accommodative ET occurred in 60% of cases, and only 35.7% were high hyperopes. All but 1 patient presented with XT at distance. In response to the XT, a mean decrease in hyperopic prescription of 1.55 ± 0.48 D was given (N = 17); only 1 case reverted to ET. Eventually, 43% underwent XT surgery, with similar rates between those who had refractive management and those who did not.

CONCLUSIONS

NCX occurs in both accommodative and nonaccommodative ET; high hyperopia is present in only one-third of cases. On average, drift to XT occurs within 5 years. Refractive management has a modest result. No predictive risk factors were identified. Our findings challenge hyperopia-linked theories of causation. Nonrefractive explanations, such as the role of the vergence system, deserve further study.

Gender differences in horizontal strabismus: Systematic review and meta-analysis shows no difference in prevalence, but gender bias towards females in the clinic

Background

Strabismus is a misalignment of the visual axis that affects 2-3% of the population and can lead to loss of binocular vision. It is currently controversial whether there is a gender difference in the most common form of visual misalignment: horizontal strabismus. Some studies claimed that more females than males have an outward deviation (exotropia), while others concluded that there is no significant gender difference. No previous work has systematically explored gender differences in horizontal strabismus or has compared the results of population-based studies with those of clinic-based studies.

Methods

We conducted a systematic review and meta-analysis of studies reporting the prevalence of horizontal strabismus. We included 73 population-based studies and compared their disclosed gender population with that in 141 comparable clinical-based studies. We analysed the data according to gender, strabismus type (esotropia, exotropia), and geographic region/ethnicity.

Results

Summary statistics showed a nearly identical prevalence of horizontal strabismus (2.558% for males, 2.582% for females), esotropia (1.386% males vs. 1.377% females), and of exotropia (1.035% males vs. 1.043% females). Meta-analysis results showed that these differences between males and females were not statistically significant (odds ratio (OR) = 1.01; 95% confidence interval (CI) = 0.97-1.10), but that females were significantly more frequent (by 7.50%) in clinic-based studies than males, with 5.00% more females for esotropia, and 12.20% more females for exotropia when adjusted for the population's sex ratio. The extent of the female gender bias differed between geographic regions/societies, with Asians having the lowest bias towards females and Latin American countries having the strongest bias.

Conclusions

Males and females have the same prevalence of horizontal strabismus, including exotropia. Females with strabismus seek health care or are brought to clinics significantly more often than males. This is an example of gender bias in health care in favour of females rather than males, apparently because parents - erroneously fearing only cosmetic consequences - are more concerned about strabismus in their daughters than their sons. Societal attitudes towards females, as well as economic factors (insurance status), appear to be relevant factors that determine the magnitude of the gender bias in horizontal strabismus.

A multimodal MRI study of functional and structural changes in concomitant exotropia

The present prospective study aimed to investigate the structural and functional changes in patients with concomitant exotropia using multimodal MRI. A total of 11 adult patients with concomitant exotropia (5 males and 6 females) and 11 healthy adult individuals (5 males and 6 females) were recruited and examined using multimodal MRI techniques. Near and distance exotropia deviation angles were measured. The structrual changes were evaluated using the gray matter volume. Functional reorganization was assessed using the amplitude of low-frequency fluctuation, regional homogeneity and resting-state functional connectivity (FC) on MRI. No significant differences could be found in terms of sex, age or body mass index between the two groups. However, the near and distance exotropia angles were significantly higer in the concomitant exotropia group compared with those in the normal control group (P<0.001). Compared with those in normal individuals, the bilateral thalamus, right middle temporal gyrus (MTG) and right cuneus had significantly reduced gray matter volumes in the concomitant exotropia group (false discovery rate corrected, P<0.05). Reduced FC was found between the bilateral thalamus and the bilateral precuneus, between the right MTG and the right medial superior frontal gyrus in addition to the right precuneus, and between the right cuneus and the right primary sensorimotor cortex (P<0.05, Gaussian random-field corrected) in the concomitant exotropia group compared with that in the normal individuals. In conclusion, the present study indicated that structural and functional reorganization occurs in specific brain regions of patients with concomitant exotropia. These reorganized areas appeared to mainly involve the subcortical structures and related cortices that process visual information.

Early post-operative angle as a predictor of surgical success in adult patients with intermittent exotropia

Purpose: Intermittent exotropia is a condition where divergent strabismus is present at certain times or fixation distances and is surgically treated with bilateral lateral rectus recession or unilateral lateral rectus recession with medial rectus resection. The main purpose of our study is to assess the relationship between the initial post-operative deviation and surgical outcomes in adult exotropes undergoing recess-resect surgery. Methods: A retrospective chart review was performed on adult patients who underwent unilateral recess-resect surgery for intermittent exotropia between March 2010 and February 2022 at a single institution with at least 3 months of follow-up. Based on their motor alignment at 2 weeks following surgery, they were categorized as having exodeviation, esodeviation within 10 PD and esodeviation exceeding 10 PD. Surgical success was defined as motor alignment within 10 PD of exotropia and 5 PD of esotropia at distance and near at final follow-up. Results: 93 patients were included, 55% female and average age was 37 years. At postoperative week 2, 26 patients demonstrated residual exodeviation (Group A), 53 patients demonstrated an esodeviation of within 10 PD (Group B) and 14 patients demonstrated an esodeviation greater than 10 PD (Group C). There were no significant differences in pre-operative and demographic factors between the group. At the final follow-up, surgical success was observed in 57 patients: 12 in Group A, 41 in Group B and 4 in Group C (P < .01). Conclusion: Overcorrection of within 10 PD at 2 weeks following surgery showed a more favorable surgical outcome compared to exodeviation or esodeviation exceeding 10 PD.

Expanding the phenotypic spectrum of Chromosome 16p13.11 microduplication: A multicentric analysis of 206 patients

INTRODUCTION

Recurrent chromosome 16p13.11 microduplication has been characterised in the literature as a cause of developmental delay, learning difficulties and behavioural abnormalities. It is a neurosusceptibility locus and has incomplete penetrance and variable expression. Other clinical features, such as cardiac abnormalities have also been reported. The duplicated region contains the MYH11 gene, which encodes the protein myosin-11 and is a component of the myosin heavy chain in smooth muscle. Recent literature has suggested 16p13.11 microduplication as one of the possible risk factors for thoracic aortic aneurysms and dissection (TAAD). Therefore, we studied the detailed phenotype of cases of chromosome 16p13.11 microduplication from seven centres in the United Kingdom (UK) to expand the phenotype, focusing on the cardiac abnormalities.

METHODS

All individuals with a chromosome 16p13.11 microduplication seen in Clinical Genetics prior to June 2017 in 6 centres (prior to 2018 in the seventh centre) were identified through the regional genetics laboratory databases. A Microsoft Excel® proforma was created and clinical data was collected retrospectively from clinical genetics databases from the seven genetics services in the UK. The data was collated and analysed collectively.

RESULTS

The majority of the individuals presented with (72%) developmental delay and (62%) behavioural abnormalities, in keeping with the published literature. 27% had some dysmorphic features, 14% had visual impairment and 8% had congenital cardiac abnormalities. Echocardiograms were performed in 50% of patients, and only 3.8% patients had aortic dilatation and no one had aortic dissection. 9.7% of patients were found to have a second genetic/chromosomal diagnosis, especially where there were additional phenotypic features.

CONCLUSION

16p13.11 microduplication is a neurosusceptibility locus and is associated with variable expression. It may be helpful to refer children with 16p13.11 microduplication for a cardiac review for congenital cardiac abnormalities and also for ophthalmological assessment. Further prospective studies with cardiac assessments are recommended in this cohort of patients to determine whether ongoing aortic surveillance is indicated. Guidelines about the frequency of surveillance are indicated, especially in individuals with normal cardiac findings. We also highlight the importance of considering a second diagnosis if the phenotype is inconsistent with that reported.

The Influence of Part-Time Occlusion Therapy on Control of Intermittent Exotropia: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Intermittent exotropia is the most prevalent subtype of exotropia in children. Part-time occlusion (PTO) as an anti-suppression therapy was applied for nonsurgical management of intermittent exotropia.

OBJECTIVE

The aim of the study was to compare the effectiveness of PTO therapy and observation in the treatment of intermittent exotropia.

METHOD

An exhaustive search of the literature from PubMed, Embase, Web of Science, and Cochrane Library databases was carried out until July 2022. No language restrictions were applied. The literature was rigorously screened against eligibility criteria. Weighted mean differences and 95% confidence interval (CI) were calculated.

RESULTS

A total of 4 articles with 617 participants were included in this meta-analysis. Our pooled results showed that PTO exhibited superior effects compared to observation, with greater decrease in exotropia control at distance and near (MD = -0.38, 95% CI: -0.57 to -0.20, p < 0.001; MD = -0.36, 95% CI: -0.54 to -0.18, p < 0.001); patients subjected to PTO therapy had greater decrease in distance deviations (MD = -1.95, 95% CI: -3.13 to -0.76, p = 0.001), and there was greater improvement in near stereoacuity among the PTO group in comparison with the observation group (p < 0.001).

CONCLUSIONS

The present meta-analysis indicated that PTO therapy showed a better effect in improving control and near stereopsis and decreasing distance exodeviation angle of children with intermittent exotropia in comparison with observation.

The Influence of Overminus Lens Therapy on Control of Intermittent Exotropia: A Meta-Analysis of Randomized Clinical Trials

BACKGROUND

Intermittent exotropia (IXT) is the most common type of strabismus, overminus lens (OML) therapy is frequently prescribed to treat IXT.

OBJECTIVES

The purpose of this study was to compare the effectiveness of OML and observation in the treatment of IXT.

METHOD

An exhaustive search of the literature in PubMed, Embase, Web of Science, and Cochrane Library databases was performed until July 2022. No language restrictions were used. The literature was rigorously screened according to eligibility criteria. Weighted mean differences and 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 4 articles with 561 participants were included in this meta-analysis. Our pooled results showed that OML demonstrated superior outcomes compared with observation, with greater decreases in distance and near exodeviation control (MD = -1.08, 95% CI: -1.96 to -0.20, p = 0.02; MD, -0.64, 95% CI: -1.15 to -0.13, p < 0.001). Patients who received OML therapy had a greater decrease in the deviation at both distance and near (MD = -4.00, 95% CI: -7.03 to -0.98, p < 0.001; MD = -4.79, 95% CI: -6.29 to -3.30, p < 0.001). There was no statistical difference between the two groups in terms of post-treatment proximal stereopsis (MD, 0.00, 95% CI: -0.08 to 0.08, p = 1.00).

CONCLUSIONS

The present meta-analysis indicated that OML therapy was effective in improving the control and decreasing exodeviation angle of IXT. However, it seemed not to be effective in improving the level of near stereopsis.

The effect of strabismus surgery on the learning abilities of school-aged children

PURPOSE

To evaluate whether strabismus surgery improves the learning performance - calculation, reading and drawing - of school-aged children.

METHODS

In a case-control study, patients between the ages of 7 and 10 years with horizontal strabismus, recommended for surgical correction, were prospectively included. Reading, calculating and drawing abilities were evaluated before and 3 months after corrective strabismus surgery using standardized tests. Cases were compared to control patients: patients with a surgical indication postponed due to the COVID lockdown.

RESULTS

Forty-two operated patients and 42 controls between the ages of 7 and 10 years with horizontal strabismus were included. The average reading speed was 65.8 words per minute pre-operatively compared to 80.6 words per minute post-operatively (p = 0.0038). The average drawing score was 71.1 pre-operatively compared to 84.3 post-operatively (p = 0.012). The average calculation score was 3.2 pre-operatively compared to 3.4 post-operatively (p = 0.363). Improvement given by strabismus surgery was confirmed avoiding the learning effect by comparison with the control group. The improvements observed were more significant in the youngest patients and esotropia.

CONCLUSIONS

This study highlights that strabismus surgery significantly improved the children's reading fluency and drawing task execution. These encouraging data should be taken into account when considering the indications for strabismus surgery.

Spectrum of ophthalmic diseases in children hospitalized in a tertiary ophthalmology hospital in China from 2010 to 2019

BACKGROUND

Describing the pattern of pediatric eye diseases is necessary for appropriate eye care in children. This study explored the spectrum and characteristics of pediatric ophthalmic diseases in a typical tertiary ophthalmology hospital in China.

METHODS

A retrospective study was conducted at a tertiary ophthalmology hospital between 2010 and 2019 in Guangzhou, China. This study included 44,552 inpatients who were younger than 18 years old. Demographic and diagnostic data were collected from the electronic medical record system. Multiphase regression analysis was used to estimate trends in the annual percentages of ten common ophthalmic diseases.

RESULTS

From 2010 to 2019, 44,552 inpatients met the inclusion criteria. The majority were male (61.9%), aged 7 to 12 years (30.3%) and self-paying (56.6%). The top ten conditions were refractive error (41.2%), strabismus (36.1%), cataract (13.6%), trauma (11.8%), congenital ptosis (8.8%), tumor (8.1%), amblyopia (7.1%), glaucoma (7.0%), entropion and trichiasis of eyelid (7.0%), and retinal detachment (6.5%). The annual percentage changes (APCs) for refractive error, strabismus, and retinal detachment were 9.3% (95% CI, 8.1-10.5%), 4.7% (95% CI, 3.8-5.6%) and - 2.8% (95% CI, - 5.1% to - 0.4%) respectively. For trauma, the average APC (AAPC = -9.2%, (95% CI, - 12.1% to - 6.2%) decreased gradually from 2010 to 2015 (APC = -4.2% (95% CI, - 8.8-0.7%)) and decreased rapidly from 2015 to 2019 (APC = -15.1% (95% CI, - 21.0% to - 8.7%)).

CONCLUSIONS

Pediatric ophthalmic diseases are common in China. Preventive strategies and health education aimed at the prevention of refractive error, strabismus, and entropion and trichiasis of eyelid will be crucial in reducing the burden of pediatric ophthalmic diseases on health care systems and human development.

Automated Mathematical Algorithm for Quantitative Measurement of Strabismus Based on Photographs of Nine Cardinal Gaze Positions

This study presents an automated algorithm that measures ocular deviation quantitatively using photographs of the nine cardinal points of gaze by means of deep learning (DL) and image processing techniques. Photographs were collected from patients with strabismus. The images were used as inputs for the DL segmentation models that segmented the sclerae and limbi. Subsequently, the images were registered for the mathematical algorithm. Two-dimensional sclera and limbus were modeled, and the corneal light reflex points of the primary gaze images were determined. Limbus recognition was performed to measure the pixel-wise distance between the corneal reflex point and limbus center. The segmentation models exhibited high performance, with 96.88% dice similarity coefficient (DSC) for the sclera segmentation and 95.71% DSC for the limbus segmentation. The mathematical algorithm was tested on two cranial nerve palsy patients to evaluate its ability to measure and compare ocular deviation in different directions. These results were consistent with the symptoms of such disorders. This algorithm successfully measured the distance of ocular deviation in patients with strabismus. With complementation in the dimension calculations, we expect that this algorithm can be used further in clinical settings to diagnose and measure strabismus at a low cost.

Functional changes in the visual cortex in preoperative and postoperative patients with intermittent exotropia: study protocol for a non-randomised case-control clinical trial

INTRODUCTION

Intermittent exotropia (IXT) is the most common type of divergent squint. IXT is primarily a cortical neurologic dysfunction disorder, occurring as a result of the insufficient maintenance of sensory and motor fusion. Recent reports have demonstrated the relationship between IXT and visual cortical impairment. We planned to assess blood oxygen level-dependent (BOLD)-functional magnetic resonance imaging (fMRI) in patients with IXT during the preoperative and postoperative follow-ups to evaluate the functional changes in the visual cortex.

METHODS AND ANALYSIS

A total of 90 Chinese subjects will be recruited, and their ages will be between 18 and 40 years old. The subjects will include the surgical treatment (ST) group (45 subjects with IXT who will undergo surgery) and the HC group (45 age-matched, sex-matched and education-matched healthy volunteers). The assessments will include the following aspects: fMRI and general ophthalmic examinations, optometry measurements and strabismus-related tests, such as the ocular deviation, binocular vision test and Newcastle Control Score (NCS). Each subject will complete the resting-state BOLD-fMRI, and the sequences will include echo planar imaging (EPI) pulse and 3-dimensional brain volume (3D-BRAVO) to acquire high-resolution images. The follow-up schedule will be 6 and 12 months after the surgery. The primary outcome will be determined by cortex changes in BOLD-fMRI in the ST group before and after surgery. We will also compare the HC group with the preoperative subjects in the ST group. The secondary outcomes will be changes in strabismus-related examinations, such as binocular visual function and NCS.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Medical Ethics Committee of Beijing Tongren Hospital. We plan to publish the results of this study in a peer-reviewed journal article.

TRIAL REGISTRATION NUMBER

ChiCTR2100048852.

Comparison of Botulinum toxin type A with surgery for the treatment of intermittent exotropia in children

Background

The aim of this study was to observe the effectiveness of botulinum toxin type A (BTA) in the treatment of intermittent exotropia (IXT) in children compared with strabismus surgery.

Methods

One hundred forty-four children with a clear diagnosis of IXT and an indication for surgery were eligible for inclusion. Subjects were divided into two groups based on parental decision: the BTA injection group (injection group) or the conventional surgery group (surgery group). All cases were followed up for 6 months. The primary outcome was a comparison of the success rate (deviation between − 10 and + 10 PD) between the two groups at 6 months after the initial treatment. Secondary outcomes included change in deviation, visual function, and post-surgical complications.

Results

Seventy-two patients were enrolled in each group. At 6-month follow-up, there was no significant difference in the success rate between the injection and surgery groups (52.8% vs 66.7%, P = 0.13; postoperative deviation − 12.22 ± 10.80 PD vs − 9.17 ± 10.30 PD, P = 0.09). The binocular Visual function, except for near stereoacuity, improved after treatment in both groups, while the fusion recovery rate was higher in the surgical group (68.1% vs 95.8%, P < 0.001). Transient complications in the injection group included diplopia, ptosis, and subconjunctival hemorrhage, whereas subconjunctival hemorrhage, conjunctival edema, foreign body sensation, pain, and diplopia were seen in the surgical group. The complications of BTA were relatively mild.

Conclusions

BTA is as effective as surgery in the treatment of IXT in children, but the recovery of the fusion is lower than surgery.

Trial registration

The study has completed the clinical registration on (ChiCTR-INR-17013777).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02285-2.

Commonly occurring genetic polymorphisms with a major impact on the risk of nonsyndromic strabismus: replication in a sample from Finland

PURPOSE

To replicate associations between polymorphisms in the WRB and TSPAN10 genes and strabismus in an independent Finnish cohort and to calculate their population attributable risk.

METHODS

Polymorphisms in the WRB (rs2244352) and TSPAN10 (rs6420484) genes were investigated in individuals from the FinnGen study group who had one of three categories of strabismus, with clinical diagnoses of (1) "strabismus-all subtypes" (3,515 cases and 173,384 controls), (2) "convergent concomitant strabismus" (ICD-10 code H50.0; 737 cases and 170,976 controls), and (3) "divergent concomitant strabismus" (ICD-10 code H50.1; 1,059 cases and 170,976 controls).

RESULTS

The WRB polymorphism was associated with "all subtypes" of strabismus (OR = 1.08; P = 0.008) and divergent strabismus (OR = 1.11; P = 0.046) but not with convergent strabismus (P = 0.41). The WRB polymorphism had a population attributable risk of 3.4% for all strabismus subtypes and 4.7% for divergent strabismus. The TSPAN10 polymorphism was associated with all three strabismus phenotypes: "all subtypes" (OR = 1.08; P = 0.002), convergent strabismus (OR = 1.19; P = 0.001) and divergent strabismus (OR = 1.20; P =7.21E-05). The population attributable risk for the TSPAN10 polymorphism was 6.0% for any strabismus, 13.3% for convergent strabismus, and 13.9% for divergent strabismus.

CONCLUSIONS

Genetic association with strabismus was replicated in a Finnish cohort for two common polymorphisms. Under the assumption that these polymorphisms are independent of other risk factors, they are responsible for up to 20% of isolated cases of strabismus in Finland, similar to estimates in other European populations.

Strabismus outcomes after surgery: the nationwide SOS France study

PURPOSE

To describe the types of strabismus operated on, the surgical procedures performed, and the 2-year reoperation rate in France.

METHODS

Entire population 5-year cross-sectional analysis of a national medico-administrative database in France between January 2013 and December 2017 included all patients who underwent a first strabismus surgery, with a 2-year follow-up. Patient identification was based on the diagnostic codes of the 10th International Classification of Diseases and surgical procedures on the codes of the Common Classification of Medical Acts. A subgroup analysis comparing non-paralytic and paralytic strabismus was performed.

RESULTS

Among the 56,654 patients included (women: 50.8%), 26,892 (47.5%) patients were under 10 years old. Overall, 52,711 (93%) were diagnosed with non-paralytic strabismus and 3,943 (7%) with paralytic strabismus. Among the non-paralytics, the most frequent diagnosis was esotropia (21,282, 37.6%), followed by exotropia (14,392, 25.4%) and vertical strabismus (2,017, 3.6%). Among the paralytics, fourth cranial nerve palsy (1,499, 2.6%) was more frequent than sixth cranial nerve palsy (691, 1.2%) and third cranial nerve palsy (431, 0.8%). The 2-year reoperation rate was 7.7% (4,362 patients), the lowest for non-paralytic (7.4%) and the highest for paralytic (11.4%).

CONCLUSION

This first French population-based study about strabismus will contribute to the evaluation of practices at a national level and permit comparisons between countries. Although the 2-year reoperation rate was found to be 1 out of 13 patients, it should be interpreted with caution. Long-term follow-up is still warranted due to considerable variability of the type and severity of strabismus as well as surgical practices.

Attitude and related factors towards strabismus among adults living in Gondar town, Northwest Ethiopia: a community-based cross-sectional study

Cultural belief in Ethiopia showed that strabismus can be caused by exposure to sunlight during infancy, an outrage from God, and looking sideways. In addition, Ethiopians also believe that strabismus can resolve by its self and is a sign of good luck. Due to these reasons many patients with strabismus come to eye care clinics after developing amblyopia. This study aimed to assess the level of attitude and related factors toward strabismus among adults living in Gondar town, Northwest Ethiopia. A community-based cross-sectional study was conducted on a sample size of 634 adults from April 9 to April 23, 2019. Data were collected using a pretested structured questionnaire through face-to-face interviews, and the study participants were chosen by applying a multistage random sampling technique. Data were entered with EPI info version 7 and imported into SPSS version 20 for analysis. Frequency, statistical summary, and cross-tabulations were used for the descriptive analysis of the entered data. Binary logistic regression was fitted, and all independent variables with a P-value of less than 0.2 in the bivariable analysis were entered into a multivariable binary logistic regression. Variables with a P-value of less than or equal to 0.05 were considered statistically significant. Respondents who answered greater than or equal to the median score of attitude-related questions were designated to have a favorable attitude toward strabismus. In this study, 602 adults were participated with a response rate of 94.9% and the median age of the participants was 33 ± 14 years. The overall proportion of favorable attitudes toward strabismus was 71.8%. Having secondary school as an educational status (AOR = 2.8 (95% CI: 1.2, 6.4)) and heard about strabismus (AOR = 7.4 (95%CI: 3.7, 14.9)) were positively whereas being unemployed (AOR = 0.3(95% CI: 0.1, 0.7)) and high monthly income (AOR = 0.5(95%CI: 0.3, 0.9)) were negatively associated with a favorable attitude regarding strabismus. Eighty-five percent (88.5%) of participants agreed that early treatment of strabismus had a better outcome. Besides, 57.6% of participants have agreed that untreated strabismus can cause amblyopia. About three fourth of the study participants had a favorable attitude toward strabismus. Educational status, heard about strabismus, occupation, and monthly income were significantly associated with a favorable attitude toward strabismus. Most of the study participants agreed that untreated strabismus can cause poor cosmoses. Fear of surgery and high cost were reported by study participants as the main barriers to seeking treatment of strabismus.

Observation on the Curative Effect of Microsurgery in 154 Children with Strabismus and Analysis of Its Influencing Factors

Strabismus is a common ophthalmic disease in the process of child body development, in which the two eyes cannot gaze at the target at the same time, and the incidence of this disease of children is higher. In children with esotropia, exotropia, and up and down strabismus and other typical symptoms, the cause is genetic, innerve, and refractive and regulated, and not receiving timely treatment may lead to stereo vision and diplopia and other phenomena, affecting their learning and life. Surgical treatment is the main treatment for strabismus at present. Traditional orthodontic surgery is performed by doctors under the naked eye, often due to improper operation or suture error and other factors, resulting in more postoperative complications, such as more tissue damage, conjunctival congestion, and muscle suture reaction, which seriously affect the clinical effect of surgical treatment. In recent years, with the continuous development of microsurgical technology, the correction of strabismus under a microscope has been widely carried out in clinic. The operation under the microscope makes the operation more delicate and accurate, overcomes the defects of traditional surgery, and highlights the advantages of minimally invasive surgery. The purpose of this study was to investigate the effect of microsurgical techniques in the treatment of strabismus in children and to analyze the factors influencing the outcome. The results showed that microsurgical strabismus correction in the treatment of strabismus children has short operation time, less intraoperative blood loss, short hospital stay, high efficiency, and less complications, which is worthy of popularization. Age, preoperative strabismus angle, refractive error, distance stereopsis injury, near stereoscopic injury, and duration of disease were all independent influencing factors of postoperative efficacy.

Subclinical markers of strabismus in children 5-18 years of age

PURPOSE

To report the prevalence of subclinical markers of strabismus from a community-based screening of children.

METHODS

A family history and ophthalmic examination (including six markers of strabismus: oblique muscle dysfunction, stereopsis <60 arcsec, monofixation, nasal-temporal pursuit asymmetry, dissociated strabismus, and anisometropia) were obtained from consecutive children, aged 5-18 years, in the local school system and the pediatric outpatient clinic of Mayo Clinic, Rochester, Minnesota.

RESULTS

A total of 1,000 children (498 males [49.8%]) were examined at a mean age of 10.6 years (range, 5-18.98). Of the 1,000, 57 (5.7%) had strabismus, and 130 (13%) had some form of phoria. Of the 943 children without strabismus, 103 (10.9%) had one or more of the six subclinical markers, including 43 (4.5%) with inferior oblique dysfunction, 37 (3.9%) with anisometropia, 34 (3.6%) with subnormal stereopsis, 6 (0.6%) with nasal-temporal pursuit asymmetry, 3 (0.3%) with monofixation, and none with dissociated strabismus. A subclinical marker of strabismus occurred in 20 (12.7%) of the 157 nontropic subjects who had a family history of either strabismus, amblyopia, or both and in 83 (10.6%) of the 786 nontropic children without a family history.

CONCLUSIONS

In this community-based screening of children, subclinical disorders of binocular vision occurred in 10%-13% of children without strabismus, of which inferior oblique muscle dysfunction, anisometropia, and subnormal stereopsis were most prevalent. Identifying these disorders among strabismic families may be useful in elucidating the genetic puzzle of childhood strabismus.

Surgery at early versus late for intermittent exotropia: a Meta-analysis and systematic review

AIM

To compare the outcomes between early surgery and late surgery for intermittent exotropia (IXT) with a Meta-analysis.

METHODS

Scientific databases including PubMed, Embase, Web of Science, Cochrane and China National Knowledge Infrastructure were searched prior to December 16, 2019. From this broad database search, we performed some Meta-analysis including eleven independent studies, to further evaluate the outcome(s) when comparing early versus late surgery for IXT. The boundaries between early and late surgery and the surgery methods were not inconsistent, so subgroup analyses were conducted by different boundaries of age at surgery and different surgical approaches. The pooled odds ratios (ORs) and the 95% confidence interval (CI) were estimated according to the random-effects model for high heterogeneity between studies.

RESULTS

Eleven retrospective studies were included in this Meta-analysis. No significant difference between early and late surgery was observed for IXT patients (OR_{First follow-up}=0.88, 95%CI 0.53-1.44, P=0.61; OR_{Final follow-up}=1.48, 95%CI 0.94-2.31, P=0.09). However, sensitivity analysis performed by sequentially omitting individual studies showed that the final follow-up result was not stable. Subgroup analyses revealed that an earlier surgical procedure could lead to a better outcome in the 4-year boundary subgroup as well as the bilateral lateral rectus recession (BLR) subgroup for the final follow-up (OR_4y=2.64, 95%CI 1.57-4.44, P=0.00; OR_BLR=2.25, 95%CI 1.36-3.74, P=0.00).

CONCLUSION

Early surgery for IXT provides a better long term follow-up outcome when patients are younger than 4 years old or choose the BLR surgical method.

Prevalence of Strabismus and Its Associated Factors Among School-Age Children Living in Bahir Dar City: A Community-Based Cross-Sectional Study

INTRODUCTION

Strabismus is a manifest deviation of the eye that exceeds the control of the fusional mechanism so that the eyes are misaligned under binocular conditions. Its prevalence reaches from 0.7% to 5% globally and 1.5% to 17.9% in Ethiopia.

OBJECTIVE

This study aimed to assess the prevalence of strabismus and its associated factors among school-age children living in Bahir Dar city.

METHODS

A community-based cross-sectional study was conducted from April 15 to May 25, 2019, in Bahir Dar city and a total of 632 participants were recruited using a multistage sampling technique. The data were collected with a face-to-face interview, Snellen acuity, prisms, pen torch, portable slit lamp, and ophthalmoscope. The collected data were entered into Epi Info version 7 and transposed to statistical package for social science version 20 for formal statistical analysis. Frequency (percentage), mean (standard deviation), tables and graphs were used to present the summary statistics. All variables with a p-value of less than 0.2 in bi-variable logistic regression were entered into multiple logistic regression and variables with a p-value of less than 0.05 were taken as significantly associated with strabismus. The strength of association between variables was shown with an odds ratio and a 95% confidence interval.

RESULTS

A total of 611 children participated with a response rate of 96.7% and a mean age of 12.3 (±3.25). The prevalence of strabismus was 31 (5.0%), 95% CI: (3.45, 6.97). Family history of strabismus (AOR= 3.9 (95% CI: 1.71, 11.22)), hyperopia ≥ +3.00 diopters sphere (AOR=5.3 (95% CI: 2.01, 10.77)), and not with exclusive breastfeeding (AOR= 2.9 (95% CI: 1.14, 4.71)) were the only risk factors found for strabismus.

CONCLUSION

The prevalence of strabismus was 5% among children living in Bahr Dar city. A family history of strabismus, not with exclusive breastfeeding, and hyperopia ≥ +3.00 diopters sphere were associated with strabismus.

An artificial intelligence platform for the diagnosis and surgical planning of strabismus using corneal light-reflection photos

Background

Strabismus affects approximately 0.8–6.8% of the world’s population and can lead to abnormal visual function. However, Strabismus screening and measurement are laborious and require professional training. This study aimed to develop an artificial intelligence (AI) platform based on corneal light-reflection photos for the diagnosis of strabismus and to provide preoperative advice.

Methods

An AI platform consisting of three deep learning (DL) systems for strabismus diagnosis, angle evaluation, and operation plannings based on corneal light-reflection photos was trained and retrospectively validated using a retrospective development data set obtained between Jan 1, 2014, and Dec 31, 2018. Corneal light-reflection photos were collected to train the DL systems for strabismus screening and deviation evaluations in the horizontal strabismus while concatenated images (each composed of two photos representing different gaze states) were procured to train the DL system for operative advice regarding exotropia. The AI platform was further prospectively validated using a prospective development data set captured between Sep 1, 2019, and Jun 10, 2020.

Results

In total, 5,797 and 571 photos were included in the retrospective and prospectively development data sets, respectively. In the retrospective test sets, the screening system detected strabismus with a sensitivity of 99.1% [95% confidence interval (95% CI), 98.1–99.7%], a specificity of 98.3% (95% CI, 94.6–99.5%), and an AUC of 0.998 (95% CI, 0.993–1.000, P<0.001). Compared to the angle measured by the perimeter arc, the deviation evaluation system achieved a level of accuracy of ±6.6º (95% LoA) with a small bias of 1.0º. Compared to the real design, the operation advice system provided advice regarding the target angle within ±5.5º (95% LoA). Regarding strabismus in the prospective test set, the AUC was 0.980. The platform achieved a level of accuracy of ±7.0º (95% LoA) in the deviation evaluation and ±6.1º (95% LoA) in the target angle suggestion.

Conclusions

The AI platform based on corneal light-reflection photos can provide reliable references for strabismus diagnosis, angle evaluation, and surgical plannings.

A randomized trial evaluating efficacy of overminus lenses combined with prism in the children with intermittent exotropia

BACKGROUND

To evaluate the efficacy of overminus lenses combined with prism spectacles in children of 3 to 6 years of age with intermittent exotropia (IXT).

METHODS

Sixty patients with IXT were randomly assigned to the treatment and observation groups. Each group included 30 IXT children aged 3 to 6 years. The treatment group was prescribed overminus lenses of - 2.50 D incorporated with the 2 PD base-in prisms on each side. Ocular alignment, the status of binocular vision, as well as the refraction changes were carried out and followed at 1, 3, 6, and 12 months. A revised form of the Newcastle Control Score (NCS) was used to evaluate the patients' ability to control their IXT.

RESULTS

After 12 months, the mean refractive error was 1.42 ± 1.25 D, and 1.43 ± 1.12 D for the observation and the treatment group, respectively (95% CI: - 0.61 to 0.62)); the mean exotropia control score was 5.72 ± 1.28 and 1.75 ± 1.18 in the observation and the treatment group, respectively (95% CI: - 4.63 to - 3.33); the mean near stereoacuity was 2.16 ± 0.42 log arcsec and 1.91 ± 0.26 log arcsec in the observation and the treatment group, respectively (95% CI: - 0.44 to - 0.06).

CONCLUSIONS

In our randomized clinical trial, overminus spectacles with prism significantly improved the control of IXT and stereopsis, by reducing the angle of strabismus in children with IXT. This treatment does not appear to cause myopia, at least in the manner used this series. A further randomized trial is warranted to assess the effect of overminus spectacles with prism after the treatment has been discontinued.

TRIAL REGISTRATION

This study adheres to CONSORT 2010 guidelines. Chinese Clinical Trial Registry, ChiCTR1900025243 . Registered 17 August 2019.

Fifteen-minute consultation: Managing a child with a new-onset squint

OBJECTIVE

To provide a systematic approach to the child with a new squint.

METHOD

Review of the current available literature.

CONCLUSION

Squint is a common presentation in the paediatric population. Although the parents' primary concern may be cosmetic, a new squint in childhood may be the first sign of a serious or life-threatening ocular or neurological pathology. Thorough assessment and timely referral are essential.

Knowledge towards Strabismus and Associated Factors among Adults in Gondar Town, Northwest Ethiopia

Introduction. Strabismus/squint is an ocular misalignment in which the eyes are not properly aligned with each other. It is an avoidable cause of blindness and has a global prevalence which ranges from 2% to 6%. Knowledge of eye diseases is important in encouraging people to seek early treatment, which further helps in reducing the burden of visual impairment. Studies in Ethiopia showed that the level of good knowledge was 37%. There is a lack of information regarding knowledge and related factors of strabismus in the study area and limited in Ethiopia at large. Objective. The aim of this study was to asses knowledge about strabismus and associated factors among adults in Gondar town, Northwest Ethiopia. Methods. Community-based cross-sectional study was conducted using a pretested structured questionnaire through face to face interview from April 17 to May 01, 2019. Using multistage random sampling, 553 participants were included. Data from the entire questionnaire were coded, entered into Epi info version 7, and exported to SPSS version 20 for processing and analysis. Binary logistic regression was fitted, and variables with P value <0.05 in the multivariable logistic regression were considered as statistically significant. Results. A total of 553 adults with a response rate of 93.25% participated in the study. The median age was 33 (IQR = 14) years. Among the participants, 52.3% (95% CI: 47.9–56.4) had good knowledge towards strabismus. Being a student (AOR = 2.15, (95% CI: 1.11–4.13) was positively associated, while monthly income >5000 birrs (AOR = 0.44, 95% CI: 0.26–0.76) was negatively associated with good knowledge about strabismus. Conclusion. Almost half of the participants had good knowledge. Occupation and monthly income had a significant association with knowledge about strabismus. Since the source of information (TV/radio and Internet) was extremely important for the reliability and the level of knowledge, it is better to have sufficient media coverage.

Eye Tracking Abnormalities in School-Aged Children With Strabismus and With and Without Amblyopia

PURPOSE

To detect eye tracking abnormalities in children with strabismus in the absence or presence of amblyopia.

METHODS

A total of 100 patients aged 7 to 17 years were enrolled prospectively for 2 years from the pediatric ophthalmology clinic of the American University of Beirut Medical Center: 50 children with strabismus (including 24 with amblyopia) and 50 age- and gender-matched controls. Eye tracking with different paradigms was performed.

RESULTS

Mean age was 10.66 ± 2.90 years in the strabismus group and 10.02 ± 2.75 years in the control group. Demographic characteristics were similar with respect to vision, gender, and refraction. Four paradigms were tested using the eye tracker: (1) distance/near paradigm: patients with strabismus showed a lower fixation count and longer fixation at both distances and a tendency for decreased latency and percentage of fixation in distant elements; (2) reading paradigm: the strabismus group had a higher fixation count and duration, especially those without amblyopia; (3) location identification paradigm: strabismus group without amblyopia fixated less and with shorter duration on the most flagrant element; and (4) video paradigm: no differences in eye movements were noted.

CONCLUSIONS

Significant eye movement deficits were demonstrated in patients with strabismus compared to controls while reading text and identifying prominent elements in a crowded photograph. This was significant in the non-amblyopic subgroup. [J Pediatr Ophthalmol Strabismus. 2019;56(5):297-304.].

Utility of Magnetic Resonance Imaging (MRI) in Children With Strabismus

PURPOSE

Magnetic resonance imaging (MRI) of the brain can provide valuable information about structural abnormalities in strabismus. The aim of this study was to evaluate the utility of MRI in this regard and to identify risk factors for abnormal MRI results in children with strabismus.

METHODS

A retrospective analysis of children <18 years of age presenting with strabismus, who underwent brain MRI at Pusan National University Hospital (Busan, Korea) between January 2012 and March 2017, was performed. Clinical characteristics, MRI results, and ophthalmologic findings were reviewed. Findings were classified as normal or abnormal according to MRI results. Additionally, patients were divided according to age to compare characteristics of infantile and childhood strabismus.

RESULTS

A total of 90 patients (47 [52.2%] male, 43 [47.8%] female; mean age, 2.19 ± 0.53 years) were enrolled. Of those, 64 (71.1%) presented with normal and 26 (28.9%) with abnormal MRI results. The age at presentation was lower and abnormal findings on fundus examination were more common in the abnormal MRI group (P = .002 and P = .008, respectively). Among the patients, 46 (51.1%) had infantile strabismus and 44 (48.9%) had childhood strabismus. Global developmental delays, speech delays, and MRI abnormalities were more common in patients with infantile than in those with childhood strabismus. Ptosis and headaches were more common in patients with childhood strabismus (P = .025, P = .025, respectively).

CONCLUSION

Brain MRI was helpful for accurate diagnosis and treatment of strabismus in younger children, those with abnormal findings on fundus examination, and infants with developmental, especially speech, delays.

Characterization of Intelligence in Children with Exotropia

The effect of exotropia on the intelligence of children is unknown. This study aimed to assess the intelligence in children with exotropia and investigate the influence of the main clinical indexes of strabismus on intelligence. Eighty-four participants aged 8–12 years were enrolled, including 37 patients with exotropia (exotropia group) and 47 normal individuals (normal group). Intelligence was assessed by the Wechsler Intelligence Scale for Children—Fourth Edition (WISC-IV), including the Verbal Comprehension Index (VCI), Perceptual Reasoning Index (PRI), Working Memory Index (WMI), Processing Speed Index (PSI), and Full-Scale Intelligence Quotient (FSIQ). The exotropia group had a significantly lower PRI score but a higher PSI score than the normal group. However, there was no significant difference in the WMI, VCI, and FSIQ between groups. Multiple linear regression showed that PRI–WMI and PRI–PSI differences were significantly lower in the exotropia group. Inter-subscale correlations analysis showed that the pattern of intelligence structure was different between groups. The type of exotropia, angle of deviation, duration of symptoms, and stereoacuity had no effect on the intelligence of children with exotropia. Children with exotropia had a relatively worse performance in the perceptual reasoning skill but a better processing speed and a different pattern of intelligence structure.

Transient Increase of Wavefront Aberrations after Horizontal Rectus Muscle Surgery in Exotropia

Aims: Wavefront aberration (WA) has become one of the important indicators for measuring the visual quality. Whether strabismus surgery affects the WA remain controversial. This study aims to investigate the postoperative alterations of WA in patients who underwent horizontal rectus muscle surgery.Methods: A total of 34 patients were enrolled and divided into two groups: bilateral lateral rectus recession (BLR) group and unilateral lateral rectus recession and medial rectus resection (R&R) group. The WA was examined 1 day before surgery, 3 days, and 6 weeks after surgery using the iTrace Visual Function Analyzer (Tracey Technologies).Results: Significant increases in total WA, lower-order aberration (LOA) and higher-order aberration (HOA) of both groups were detected in 3 days after surgery (P < 0.05), while no significant differences in 6 weeks after surgery. Significant increases in astigmatism, secondary astigmatism, and trefoil of both groups were detected in 3 days after surgery (P < 0.05), while no significant differences in individual order of LOA and HOA in 6 weeks postoperatively. Z₂², Z₃³, and Z₄² of both groups increased significantly 3 days after surgery (P < 0.05) and returned to baseline level 6 weeks after surgery, while the rest Zernike coefficients remained the same postoperatively. When comparing the differences between the two groups, there were no statistically significant differences in these parameters between baseline and each follow-up visit postoperatively.Conclusions: The increase of WA restored to pre-operative level in 6 weeks after surgery, indicating the influences of horizontal rectus muscle surgery to WA were transient and reversible.

Maternal smoking during pregnancy and the risk of strabismus in offspring: a meta-analysis

The effect of maternal smoking during pregnancy on strabismus in offspring remains unclear. We conducted a meta-analysis to summarize epidemiological evidences on the association between maternal smoking during pregnancy and the risk of offspring strabismus. Eligible studies were searched from the PubMed, Ovid, Embase and CNKI databases up to May 2018. The qualities of included articles were assessed with the Newcastle-Ottawa Scale and the assessment scale recommended by the Agency for Healthcare Research and Quality. Odds ratios (ORs) corresponding with its 95% confidence intervals (CIs) were pooled to estimate the effects of maternal cigarette smoking on the risk of offspring strabismus. Subgroup analyses and meta-regression were performed to explore the potential sources of heterogeneity. The Begg's test and Egger's test were used to assess the publication bias. Eleven articles involving 4,833 patients with strabismus were included. The pooled OR showed that maternal smoking during pregnancy was significantly associated with strabismus in offspring (OR = 1.46, 95% CI = 1.32-1.60). Compared with less than 10 cigarettes per day (OR = 1.17, 95% CI = 1.06-1.29), maternal smoking 10 cigarettes or more per day during pregnancy significantly increased the risk of offspring strabismus (OR = 1.79, 95% CI = 1.39-2.31). The risk of developing esotropia and exotropia for smoking pregnant women, respectively, increased by 65% (OR = 1.65, 95% CI = 1.31-2.09 and OR = 1.65, 95% CI = 1.24-2.19) than those who did not smoke during pregnancy. Additionally, the increased risk of maternity smoking associated with offspring strabismus was stable across all subgroup analyses. Overall, maternal smoking during pregnancy was associated with a significantly increased risk of offspring strabismus and the result was persistent in subgroup analyses, suggesting the importance in changing smoking habit or smoking cessation for women who are pregnant or preparing to.

Effects of bifocals on visual acuity in children with Down syndrome: a randomized controlled trial

Purpose

Children with Down syndrome (DS) typically have reduced visual acuity (VA) and accommodation lag, but it is unclear whether prescribed glasses should correct both distance VA (DVA) and near VA (NVA) due to the lack of RCTs. We therefore conducted a multicentre RCT to compare the effects of bifocals designed to correct both DVA and NVA with distance‐correcting unifocal glasses in children with DS.

Methods

A total of 119 children with DS, aged 2–16, were randomly allocated for bifocal or unifocal glasses (with full correction of refraction error in cycloplegia) in 14 Dutch hospitals and followed during 1 year. VA data were analysed in relation to baseline VA with ancova.

Results

Treatment groups showed no differences at baseline. Shortly after receiving new corrections (~6 weeks), uncrowded NVA (bifocals 0.18 ± 0.33 LogMar; unifocals 0.09 ± 0.19 LogMar) and crowded NVA with bifocals (bifocals 0.13 ± 0.36 LogMar; unifocals 0.08 ± 0.33 LogMar) were significantly better than at baseline, but these short‐term improvements in NVA were not significantly different between the two treatments (p > 0.151). The 1‐year treatment differences were as follows: significantly larger improvement for bifocals compared to unifocals in both uncrowded NVA (bifocals 0.23 ± 0.29 LogMar, unifocals 0.12 ± 0.30 LogMar, p = 0.045) and crowded NVA (bifocals 0.31 ± 0.28 LogMar; unifocals 0.16 ± 0.30 LogMar, p = 0.017). Improvements in DVA were comparable (bifocals 0.07 ± 0.21 LogMar, unifocals 0.08 ± 0.22 LogMar, p = 0.565). Children with poor baseline VA improved more. Accommodation lag stayed unchanged.

Conclusion

After one year, bifocals with full correction of ametropia led to significantly larger improvement of both uncrowded NVA and crowded NVA in children with DS with accommodation lag compared to unifocals.

Genome-Wide Association Study Identifies a Susceptibility Locus for Comitant Esotropia and Suggests a Parent-of-Origin Effect

Purpose

To identify genetic variants conferring susceptibility to esotropia. Esotropia is the most common form of comitant strabismus, has its highest incidence in European ancestry populations, and is believed to be inherited as a complex trait.

Methods

White European American discovery cohorts with nonaccommodative (826 cases and 2991 controls) or accommodative (224 cases and 749 controls) esotropia were investigated. White European Australian and United Kingdom cohorts with nonaccommodative (689 cases and 1448 controls) or accommodative (66 cases and 264 controls) esotropia were tested for replication. We performed a genome-wide case-control association study using a mixed linear additive model. Meta-analyses of discovery and replication cohorts were then conducted.

Results

A significant association with nonaccommodative esotropia was discovered (odds ratio [OR] = 1.41, P = 2.84 × 10-09) and replicated (OR = 1.23, P = 0.01) at rs2244352 [T] located within intron 1 of the WRB (tryptophan rich basic protein) gene on chromosome 21 (meta-analysis OR = 1.33, P = 9.58 × 10-11). This single nucleotide polymorphism (SNP) is differentially methylated, and there is a statistically significant skew toward paternal inheritance in the discovery cohort. Meta-analysis of the accommodative discovery and replication cohorts identified an association with rs912759 [T] (OR = 0.59, P = 1.89 × 10-08), an intergenic SNP on chromosome 1p31.1.

Conclusions

This is the first genome-wide association study (GWAS) to identify significant associations in esotropia and suggests a parent-of-origin effect. Additional cohorts will permit replication and extension of these findings. Future studies of rs2244352 and WRB should provide insight into pathophysiological mechanisms underlying comitant strabismus.

Surgical management of intermittent exotropia: do we have an answer for all?

Intermittent exotropia (X(T)) is one of the most common form of strabismus with surgery being the mainstay of treatment. The main goal of surgery is to preserve binocular vision and stereopsis and to prevent its further loss. The decision to operate is mainly based on four aspects: increasing angle of exodeviation, deteriorating control of X(T), decrease in stereopsis for near or distance and quality of life. Bilateral lateral rectus muscle recession and unilateral lateral rectus recession with medial rectus resection, are the two most common surgical procedures performed and have been studied extensively in basic, divergence excess and convergence insufficiency types of X(T). However, there is no consensus over the relative efficacy of the two procedures in terms of postoperative alignment, residual or recurrent exotropia and consecutive esotropia with widely variable results, which can be attributed to poor understanding of the natural course of the disease. Multiple demographic, clinical and anatomic features that may influence the surgical outcomes have been studied to explain this variability. Moreover, most of the evidence regarding surgical outcomes of X(T) is from retrospective studies and the ongoing randomised prospective trials can shed light on long-term efficacy of these procedures. The goal of this review is to give a comprehensive overview of the outcomes of various surgical techniques in the management of different types of X(T), the preoperative and postoperative factors that may affect the surgical outcomes and to discuss the dilemmas faced by the treating surgeons including the effective management of overcorrection and undercorrection.

Visual and vestibular functioning, and age and surgery effects on postural control in healthy children with vertical strabismus

Purpose:

To describe visual and vestibular functioning and the effects of age and surgery effects on postural control in healthy children with vertical strabismus.

Design:

This is a comparative case series.

Methods:

We evaluated participants at the Scientific Institute Eugenio Medea during routine clinical activities. We enrolled 30 consecutive children/adolescents (age range 4–13 years) with isolated vertical strabismus, with and without corrective surgery. Participants were split into four subgroups according to age (4–8 years versus 9–13 years) and ocular surgery (surgery versus no surgery). The clinical protocol included ophthalmological, orthoptic, neurological, physiatrical, otolaryngological, and vestibular evaluations, and the instrumental protocol included ocular cyclotorsions assessment, posturography, and vestibular myogenic-evoked potentials. Main outcome measures of the study were the prevalence of study-relevant orthopedic, ocular, vestibular, and posturographic abnormalities.

Results:

Among the overall largely variable findings across patients’ groups, we found some interesting trends: larger binocular vision and convergence disorders in younger children, smaller prevalence of asymmetric vestibular-evoked potentials in operated children, less posturographic abnormalities in younger children. No clear-cut beneficial effect of surgery was found on all clinical and instrumental parameters considered, despite good re-alignment of the eyes.

Conclusion:

The pathophysiology of postural control in vertical strabismus is extremely complex and above the potential of this study design and should be specifically addressed in deeper experimental studies.

Prevalence of, and risk factors for, presenting visual impairment: findings from a vision screening programme based on UK NSC guidance in a multi-ethnic population

PURPOSE

To determine presenting visual acuity levels and explore the factors associated with failing vision screening in a multi-ethnic population of UK children aged 4-5 years.

METHODS

Visual acuity (VA) using the logMAR Crowded Test was measured in 16,541 children in a population-based vision screening programme. Referral for cycloplegic examination was based on national recommendations (>0.20logMAR in one or both eyes). Presenting visual impairment (PVI) was defined as VA >0.3logMAR in the better eye. Multivariable logistic regression was used to assess the association of ethnicity, maternal, and early-life factors with failing vision screening and PVI in participants of the Born in Bradford birth cohort.

RESULTS

In total, 2467/16,541 (15%) failed vision screening, 732 (4.4%) had PVI. Children of Pakistani (OR: 2.49; 95% CI: 1.74-3.60) and other ethnicities (OR: 2.00; 95% CI: 1.28-3.12) showed increased odds of PVI compared to white children. Children born to older mothers (OR: 1.63; 95% CI: 1.19-2.24) and of low birth weight (OR: 1.52; 95% CI: 1.00-2.34) also showed increased odds. Follow-up results were available for 1068 (43.3%) children, 993 (93%) were true positives; 932 (94%) of these had significant refractive error. Astigmatism (>1DC) (44%) was more common in children of Pakistani ethnicity and hypermetropia (>3.0DS) (27%) in white children (Fisher's exact, p < 0.001).

CONCLUSIONS

A high prevalence of PVI is reported. Failing vision screening and PVI were highly associated with ethnicity. The positive predictive value of the vision screening programme was good, with only 7% of children followed up confirmed as false positives.

Strabismus, Strabismus Surgery, and Reoperation Rate in the United States: Analysis from the IRIS Registry

PURPOSE

To describe the rates of strabismus, strabismus surgery, and strabismus surgery reoperations among all age groups in the United States.

DESIGN

Retrospective analysis of electronic health record data.

PARTICIPANTS

Patients from the IRIS (Intelligent Research in Sight) Registry.

METHODS

Description of the types and rates of strabismus and strabismus surgery from 2013 to 2016 with subgroups by age, sex, race/ethnicity, and region of the United States.

MAIN OUTCOME MEASURE

The 1-year reoperation rate for strabismus surgery performed during 2013-2015 for all age groups.

RESULTS

A total of 30 827 185 unique patients were identified; 846 477 (2.75%) had a diagnosis of strabismus: 3.02% of male patients and 2.55% of female patients (difference = 0.47%, 95% confidence interval [CI], 0.46-0.48, P < 0.0001). Strabismus surgery was performed in 40 780 (0.13%) unique patients during the 4 years. The rate of surgery ranged from 1.99% for children birth to 5 years of age to 0.05% for adults 40 years of age and older. Horizontal surgical codes were reported 38 813 times, vertical surgery codes were reported 9304 times, and superior oblique codes were reported 711 times. Adjustable sutures were used for 3027 patients (7.42%). Cases with a code for repeat eye muscle surgery or restrictive myopathy were reported for 6098 patients (14.9%). Esotropia accounted for 30.06% and exotropia in 21.77% of diagnoses reported for surgery. The rate of undergoing a reoperation within 1 year of a strabismus surgery was 6.72%, lowest for the group 6 to 9 years of age (3.95%) and increasing with age (P < 0.001) to 11.5% for patients 65 years of age and older.

CONCLUSIONS

Strabismus is an uncommonly reported diagnosis in ophthalmologic practice. Overall, approximately 1 in 750 patients in the IRIS Registry received strabismus surgery (1 in 20 with a strabismus diagnosis) during a 4-year period. Reoperations during the first year after surgery were performed for 1 in 15 patients, increasing with age at surgery. "Big" data from clinical data registries represent real-world care that can be used to develop benchmarks for clinical outcomes and to identify areas for practice improvement and training program design.

Trends in Visual Health Inequalities in Childhood Through Associations of Visual Function With Sex and Social Position Across 3 UK Birth Cohorts

Importance

Despite the existing country-specific strategies tackling social inequalities in visual health in adults, little is known about trends in visual function in childhood and its association with social position.

Objective

To investigate the distribution of childhood visual function in the United Kingdom and associations with early-life social position between 1961 and 1986, a period of significant social change.

Design, Setting, and Participants

Longitudinal cohort study using harmonized data sets from the British 1946, 1958, and 1970 national birth cohorts. In total, 14 283 cohort members with complete data on visual acuity at age 15 or 16 years, measured in 1961, 1974, and 1986, respectively, for each cohort, and social position were assessed.

Main Outcomes and Measures

Using habitual distance visual acuity (with correction if prescribed), participants were assigned to a visual function category ranging from bilateral normal to visual impairment/severe visual impairment/blindness (International Statistical Classification of Diseases, Tenth Revision, Clinical Modification). Distribution of visual function over time and associations with social position (risk ratios [RRs] and 95% confidence intervals) were analyzed.

Results

Complete data were available for 3152 participants (aged 15 years; 53% boys [n = 1660]) in the 1946 Medical Research Council National Survey of Health and Development, 6683 participants (aged 16 years; 51% boys [n = 3420]) in the 1958 National Child Development Study, and 4448 participants (aged 16 years; 48% boys [n = 2156]) in the 1970 British Birth Cohort Study. The proportion of children with bilateral normal vision decreased by 1.3% (95% CI, -5.1% to 2.7%) in 1974 and 1.7% (95% CI, -5.9% to 2.7%) in 1986. The risk of overall impaired vision increased by 1.20 times (95% CI, 1.01-1.43) and the risk of visual impairment/severe visual impairment/blindness by 1.75 times (95% CI, 1.03-2.98) during this period. Girls were consistently at increased risk of all vision impairment categories. Higher social position at birth and in childhood was associated with reduced risk of visual impairment/severe visual impairment/blindness (RR, 0.58; 95% CI, 0.20-1.68) and unilateral impairment (RR, 0.89; 95% CI, 0.72-1.11), respectively.

Conclusions and Relevance

Our study provides evidence of temporal decline in childhood visual function between 1961 and 1986. Despite the limited power of the analysis owing to the small sample size of those with impaired vision, we found an emergence of a contribution of sociodemographic status to the cohort effect that may be the antecedent of the current picture of childhood blindness. Equally, early-life social position may also have contributed to the current social patterning in visual function in older adults in the United Kingdom. These findings highlight the potential value of targeting children in national ophthalmic public policies tackling inequalities.

Pedigree Analysis of Familial Primary Concomitant Horizontal Strabismus in Northern India

PURPOSE

Familial clustering of common forms of primary strabismus like esotropia (ET) and exotropia (XT) is observed in a proportion of the strabismus cohort. The genetic components of this remain unidentified. Linkage studies have demonstrated susceptibility locus for primary strabismus at the STBMS1 locus on 7p22.1 as well as other loci on 4q28.3 and 7q31.2. Recently next generation sequencing (NGS) technology has emerged as a powerful tool in discovery genomics and a large number of novel disease-causing variants are being reported. In this study, we recruited informative families for subsequent genetic analysis for disease-causing variant identification.

METHODS

All consecutive families with two or more affected members with primary concomitant horizontal strabismus were prospectively recruited at the ophthalmic outpatients department (OPD) of Lady Hardinge Medical College, New Delhi, from August 2014 to February 2017. Detailed phenotypic evaluation and pedigree documentation was performed.

RESULTS

Of the 39 recruited families of north Indian origin, 18 families each had affected family members demonstrating either ET or XT. 100% concordance of the phenotype in the affected family members was observed in these families. While vertical transmission was observed in 17/18 families with XT, 7 with ET had affected members across one generation, 2 demonstrated consanguineous pedigree, and 2 comprised identical twin families. In 3 families, a combination of ET and XT was noted. This comprised one family with the ET and XT patients being from 2 separate arms of the family related by marriage, one family where one sibling had XT and the other had ET, and another family where the maternal aunt of the affected proband with ET had XT.

CONCLUSIONS

Subjects with familial primary concomitant strabismus recruited in this study may provide a valuable resource to unravel the genetic determinants of this condition, which is a common disorder of early childhood with high ophthalmic morbidity.