Binocular Examination in Children

This chapter introduces the reader to tests commonly performed in a binocular vision examination to determine a child's binocular status. The testings introduced in this chapter are all chairside techniques that do not involve a significant amount of extra equipment or time. The binocular examination consists of determining the ocular position and then accommodation, vergence, and ocular motor statuses. The ocular position consists of determining where the eyes point in space and if they are correctly aligned. Evaluation of ocular alignment and the ability to move the eyes with coordination can be determined with various techniques, including Hirschberg, Krimsky, cover test, as well as Modified Thorington, motor testing, and vergence ranges. This chapter will familiarize the clinician with the basics of binocular vision testing and improve the reader's comfort with the various elements of the binocular vision examination.

Miopía y Astigmatismo miópico en escolares

Existe un aumento epidémico de miopía en distintas partes del mundo. En niños, la evidencia apunta hacia la falta de exposición a luz natural. En Chile, la situación poblacional de miopía en niños se desconoce.Objetivo: Estimar la tendencia de miopía y astigmatismo miópico en escolares de 1º y 6º básico del sistema público de educación de Chile.Sujetos y Método: Estudio ecológico en base a las confirmaciones diagnósticas del Programa Servicios Médicos de JUNAEB, periodo 2012-2018. Se estimó prevalencia anual de miopía y astigmatismo del país, por región y según sexo. La evaluación en el tamizaje contempló agudeza visual usando tabla Snellen E Abreviada, rojo pupilar, test de Hirschberg, test de Titmus, Cover test, motilidad ocular y examen de segmento anterior. Se utilizó chi2 y regresión logística para evaluar diferencias y regresión lineal para estimar cambio promedio anual.Resultados: En 2012-2018, la miopía y astigmatismo miópico tuvieron presentación geográfica heterogénea. La miopía y astigmatismo miópico ≥ 3 dioptrías aumentaron a un promedio anual de 0,11% (R2 0,67) y 1,21% (R2 0,90) en 1º básico y a 0,2% (R2 0,65) y 8,7% (R2 0,79) en 6º básico. La miopía < 3 dioptrías declinó 0,13% promedio anual (R2 0,45) en 1º básico y el astigmatismo miópico < 3 dioptrías, 0,5% (R2 0,53) en 6º básico. El astigmatismo miópico alto afectó más a hombres y la miopía < 3 dioptrías a mujeres de 6º básico.Discusión: En los escolares del sistema público de educación, la miopía y astigmatismo miópico ≥ 3 dioptrías tienden al aumento. El efecto protector de miopía que otorga la luz natural, demostrado en estudios longitudinales y experimentales, es evidencia a considerar para fomentar el tiempo de los niños al aire libre.

Effects of Orthoptic Therapy in Children with Intermittent Exotropia After Surgery: Study Protocol for a Randomized Controlled Trial

Background Intermittent exotropia (IXT) is the most common type of exotropia in China. Surgery is usually required to align the eye deviation to maintain or obtain better binocular visual function. However, there is a high rate of exodrift or recurrence in surgically treated patients. Orthoptic therapy is sometimes recommended for IXT patients after surgery. However, there is a lack of high-quality randomized controlled trials to prove that orthoptic therapy could be an effective supplement to surgical treatment for IXT patients. This study was designed to confirm such an application. This report describes the design and methodology of the Intermittent Exotropia Post-operative Treatment Clinical Trial, which is the first large-sample, blank-controlled, randomized clinical trial. Methods A total of 136 IXT patients (aged 7 to 17 years) will be enrolled and assigned to the orthoptic therapy group or blank control group according to a simple randomization scheme. Patients in the orthoptic therapy group will receive at least 2 months of orthoptic therapy, such as anti-suppression, vergence, and accommodation training. Patients in the blank control group will receive only refractive correction. All enrolled patients will need regular follow-up observation until 2 years after surgery. The primary outcome will be the proportion of participants meeting suboptimal surgical outcomes in this 2-year follow-up, which is defined as (1) exodeviation of 10 prism diopters (PD) at distance or near using the simultaneous prism and cover test (SPCT) or (2) loss of 2 or more octaves of stereoacuity from baseline, at any masked follow-up visit examination. The secondary outcomes will be the exodeviation at distance and near using the simultaneous prism and alternate cover test (PACT), magnitude of fusional convergence, stereoacuity, and accommodation. Measurements will be taken at baseline and at the 6-, 12-, 18-, and 24-month follow-ups. Discussion To the best of our knowledge, this will be the first prospective, randomized controlled study of binocular training in IXT patients after surgery. The aim of this work is to confirm the efficacy of orthoptic therapy in reducing the proportion of recurrence among IXT patients after surgery and improving binocular vision function. Trial registration: Chinese Clinical Trial Registry ChiCTR1900026891. Registered on 25 October 2019.

Refractive Errors and Binocular Vision Anomalies among Young University Students

It has been reported that refractive errors (RE) and binocular vision (BV) anomalies are common among university students. In this study we aimed to assess RE and BV status among university students in Saudi Arabia, and its relation to the academic performance. We recruited 109 participants (aged from 18 to 21 years). Visual acuity (VA) and objective refraction were used to assess the refractive status. Cover test, near-point convergence (NPC) and stereopsis tests were used to assess the BV status. Convergence insufficiency symptom survey (CISS) was applied to quantify near-work related symptoms. Mann-Whitney U test (p value was set as p &lt; 0.05) was used to compare VA, CISS, NPC and the academic performance between the groups who had heterophoria versus orthophoria. We found that there was only 38% emmetrope, while the percentage of heterophoria was 45.8%. The academic performance was not statistically different among the two groups, but CISS and stereopsis scores were significantly different (p &lt; 0.03). We concluded that RE and BV anomalies were common among university students in Saudi Arabia, but did not affect the academic performance. More studies are warranted to understand the low scores of CISS and stereoacuity, and their association with RE and BV anomalies.

Congenital dysplasia involving both medial and inferior recti: clinical features and surgical outcomes

AIM: To investigate the clinical features and surgical outcomes of congenital dysplasia involving both inferior recti (IR) and medial recti (MR) muscles. METHODS: A retrospective review was conducted including cases of simultaneous congenital dysplasia of IR and MR that were diagnosed and surgically treated at the Zhongshan Ophthalmic Center, Sun Yat-sen University, China, from July 2009 to November 2019. Ocular motility, ocular alignment at distance (6 m) and near (33 cm) by prism alternating cover test and stereoacuity were assessed in all patients before and after surgery. RESULTS: A total of five patients (four males and one female; three with right eye and two with left eye congenital dysplasia) were included in this review. The patients ranged in age from 10 to 42y (21±13.4y). The main clinical findings were hypertropia and exotropia of the affected eye, along with motility limitations in adduction and depression. Lateral rectus (LR) recession/transposition combined with IR resection was performed in one case. Two scheduled surgeries were performed in four cases, with one involving superior rectus recession and IR resection and the others LR recession and MR resection. Mean±SD pre-surgical exotropia of 51.0±31.11 prism diopter (PD) and hypertropia of 29.20±7.12 PD in the primary position were decreased to 3.6±12.90 and 3.2±10.09 PD, respectively, at two years after surgery, with a success rate of 60% and an under-correction rate of 40%. CONCLUSION: The main clinical features associated with simultaneous MR/IR congenital dysplasia are hypertropia and exotropia of the affected eye along with motility limitations in adduction and depression. Scheduled two-stage surgeries achieved a success rate of 60%.

Automated alternate cover test for ‘HINTS’ assessment: a validation study

Objective The alternate cover test (ACT) in patients with acute vestibular syndrome is part of the ‘HINTS’ battery test. Although quantitative, the ACT is highly dependent on the examiner’s experience and could theoretically vary greatly between examiners. In this study, we sought to validate an automated video-oculography (VOG) system based on eye tracking and dedicated glasses. Methods We artificially induced a vertical strabismus to simulate a skew deviation on ten healthy subjects, aged from 26 to 66, using different press-on Fresnel prisms on one eye while recording eye position with VOG of the contralateral eye. We then compared the system’s performance to that of a blinded trained orthoptist using conventional, semi-quantitative method of skew measurement known as the alternate prism cover test (APCT) as a gold standard. Results We found a significant correlation between the reference APCT and the Skew VOG (Pearson’s R2 = 0.606, p < 0.05). There was a good agreement between the two tests (intraclass correlation coefficient 0.852, 95 CI 0.728–0.917, p < 0.001). The overall accuracy of the VOG was estimated at 80.53% with an error rate of 19.46%. There was no significant difference in VOG skew estimations compared with the gold standard except for very small skews. Conclusions VOG offers an objective and quantitative skew measurement and proved to be accurate in measuring vertical eye misalignment compared to the ACT with prisms. Precision was moderate, which mandates a sufficient number of tests per subject.

To measure the amount of ocular deviation in strabismus patients with an eye-tracking virtual reality headset

Purpose To investigate the accuracy of a newly developed, eye-tracking virtual reality (VR)-based ocular deviation measurement system in strabismus patients. Methods A VR-based ocular deviation measurement system was designed to simulate the alternative prism cover test (APCT). A fixation target was made to alternate between two screens, one in front of each eye, to simulate the steps of a normal prism cover test. Patient’s eye movements were recorded by built-in eye tracking. The angle of ocular deviation was compared between the APCT and the VR-based system. Results This study included 38 patients with strabismus. The angle of ocular deviation measured by the VR-based system and the APCT showed good to excellent correlation (intraclass correlation coefficient, ICC = 0.897 (range: 0.810–0.945)). The 95% limits of agreement was 11.32 PD. Subgroup analysis revealed a significant difference between esotropia and exotropia (p < 0.001). In the esotropia group, the amount of ocular deviation measured by the VR-based system was greater than that measured by the APCT (mean = 4.65 PD), while in the exotropia group, the amount of ocular deviation measured by the VR-based system was less than that of the APCT (mean = − 3.01 PD). The ICC was 0.962 (range: 0.902–0.986) in the esotropia group and 0.862 (range: 0.651–0.950) in the exotropia group. The 95% limits of agreement were 6.62 PD and 11.25 PD in the esotropia and exotropia groups, respectively. Conclusions This study reports the first application of a consumer-grade and commercial-grade VR-based device for assessing angle of ocular deviation in strabismus patients. This device could provide measurements with near excellent correlation with the APCT. The system also provides the first step to digitize the strabismus examination, as well as the possibility for its application in telemedicine.

PREVELANCE OF HORIZONTAL STRABISMUS FOUND IN PEDIATRIC POPULATION IN A TERTIARY CARE EYE HOSPITAL IN EASTERN NEPAL

PURPOSE:To determine the prevalence of horizontal strabismus in patients less than 15 years of age. METHODS:A retrospective analysis of data of children attending pediatric OPD from January 2016 to December 2020 was done. A proforma was made and following information was entered information : history, clinical presentation, ocular examination including visual acuity, anterior and posterior segment evaluation,extraocular motility, cover tests, Prism bar cover test,worth four dot test,Bagolini's striated glasses test,Lang test,cycloplegic refraction. RESULTS: A total of 1,17,700 attended the pediatric OPD in 5 year period, prevalence of horizontal strabismus was 1.43%. Exotropia was more common than esotropia. Concomitant deviation was more common than incomitant deviation. CONCLUSION: strabismus is frequently encountered in pediatric clinics now. Proper training of pediatric ophthalmologists is required to give excellent care to these children.