Binocular Function Research Articles

NEIVATECH pilot study: immersive virtual reality training in older amblyopic children with non-compliance or non-response to patching.

Immersive virtual reality (VR) is recently being explored as a therapeutic alternative for the treatment of amblyopia. This pilot study aimed to evaluate the preliminary efficacy, safety, usability and satisfaction obtained with the use of a novel VR system (NEIVATECH) to provide binocular vision training in previously treated older amblyopic children with non-compliance or non-response to patching. A prospective, multicentre, open-label, single-arm, pilot study was conducted in which the intervention under study was 9h of therapy with the NEIVATECH system, distributed in 18 half-hour sessions spread over 1 month. A comprehensive visual assessment was conducted before and after the intervention, and at the end of the intervention the safety and usability of the system and patient satisfaction were evaluated. After therapy, statistically significant differences were observed in the near best-corrected visual acuity (BCVA) of the dominant (p = 0.022) and non-dominant (p = 0.022) eye, in stereopsis based on the Binocular Function Score (p = 0.045) and in the break (p = 0.012) and recovery (p = 0.009) points of negative fusional vergence for distance vision. The safety and usability of the system and patient satisfaction with the therapy were adequate. These findings support further investigation of this treatment option in future studies incorporating a control group with which to compare the results obtained. Trial registration: NCT04819386.

Visual quality following FS-LASIK with Q-value-guided optimized monovision in patients with myopia and presbyopia: Custom-Q in treating myopia and presbyopia

PurposeTo evaluate the objective and subjective visual quality 3 months after femtosecond laser‐assisted laser in situ keratomileusis (FS-LASIK) performed with Q-value–guided optimized monovision scheme (Custom-Q) for correction of myopia with or without astigmatism and compensate for age-related accommodation deficiency. DesignProspective before-and-after study. MethodsPatients who had Custom-Q FS-LASIK for myopia with age-related accommodation deficiency were included in this prospective study. Distance, intermediate, and near visual acuities; refraction; Q value; corneal higher-order aberrations (HOAs); accommodative and binocular function measurements; defocus curve; contrast sensitivity and a subjective questionnaire assessing near visual ability and visual discomforts were evaluated before and after surgery. ResultsClinical data of 48 cases were analyzed. The mean age was 42.73 ± 2.67 years (40 to 50 years). At the 3-month follow-up, there were 100% (48/48), 92% (44/48), and 56% (27/48) patients who achieved a binocular uncorrected distance, intermediate and near visual acuity (UDVA, UIVA, UNVA) not less than 20/20 separately. Defocus curves revealed better results postoperatively at – 1.00 D and – 1.50 D. The Q value in the dominant eyes was more positive postoperatively (P<0.001), and in the non-dominant eyes, the Q value and corneal spherical aberration (SA) became more negative (P<0.05). The accommodative amplitude (AA) and relative accommodation improved binocularly (P<0.001). The questionnaire demonstrated high patient satisfaction with near vision, and patients’ perceptions of visual discomforts had no significantly difference compare with preoperative. ConclusionFor myopic patients with age-related accommodation deficiency, the Custom-Q ablation could improve near vision without compromising distance vision. It also led to minimal changes in objective optical quality, coordination of accommodative and binocular functions, contrast sensitivity, and subjective visual discomforts perceptions.

A preliminary exploration of quantitative models for evaluating binocular visual perception impairments among patients diagnosed with stroke.

The objective of this study is to formulate and implement graded biological models pertaining to binocular visual perception function with the use of computer algorithms. We aim to quantitatively assess the location, severity, and degree of impairment in binocular visual perception among patients who have suffered stroke, thereby providing valuable insights into the repercussions of cerebral tissue damage on the visual system. To overcome the shortcomings of previous instruments used to assess binocular function in terms of stereoscopic effects and the challenges posed by physiological and psychological interference during examinations, this study optimized its approach by integrating polarized stereovision technology with computer graphic modeling techniques. This study employed computer models to assess binocular visual perception function in stroke patients. Computer models refer to psychophysical testing methods used to measure binocular visual perception function, including various assessment tasks such as recognizing inverted letters and assessing stereopsis during high-speed movements. The cross-into-circle test was used as a means to quantify perceptual eye position. Subsequently, the collected data was analyzed to assess the magnitude of impairment in binocular visual perception. The results of the study revealed a spectrum of binocular visual perception impairment among patients diagnosed with stroke, demonstrating discernible variations in the recognition of inverted letters and stereopsis across different movement speeds. Importantly, perceptual eye position measurements offered valuable insights into ocular misalignment. The computational models effectively quantified both the spatial distribution and severity of these identified impairments. Damage to brain tissue resulting from a stroke can give rise to notable impairments in binocular visual perception function. Graded biological models, formulated through computer algorithms, provide a systematic framework for the comprehensive evaluation and quantification of these impairments. The comprehension of the nature and extent of visual impairments observed in patients with stroke establishes a basis for the development of personalized visual perception learning methodologies. Based on such tailored approaches, we aim to facilitate the recovery of impaired visual function, thereby contributing to the broader objective of neural system rehabilitation.

Acute Acquired Comitant Esotropia

Acute acquired comitant esotropia (AACE) is an infrequent presentation of esotropia, characterized by sudden onset eye misalignment and diplopia. The purpose of this article is to review four cases of children diagnosed with AACE. We present 4 cases (children 610 years) of AACE. All of them suddenly developed diplopia and esotropia, with largeangle. After complete ophthalmological and neurological examinations in three cases out of four, strabismus surgery was conducted. In one case heterogenous neoplasm was detected and sent to an oncologist and neurosurgeon for evaluation and morphological verification. Bilateral medial rectus recession in two cases and unilateral recession of the medial rectus and resection of the lateral rectus in one case were performed. After strabismus surgery fully recovered binocular vision and was no longer noticeable diplopia. Neurological examinations and neuroimaging should be performed to exclude any potential intracranial disease. Surgery should be taken into consideration 6 months after the onset of the esotropia, if the deviation is stable. Strabismus surgery of AACE has good motor and sensory results and can successfully restore good binocular function The excessive use of smartphones may be associated with developing and increasing AACE.

Significance of binocular fusion in enhancing visual acuity during amblyopia treatment.

Currently, the exploration of amblyopia treatment methods is gradually shifting to the restoration of binocular visual perceptual function. Binocular fusion function, as an important component of binocular visual function, mainly reflects the patient's ability to integrate the signals received from both eyes. In this study, we investigated the relationship between binocular fusion function and improvement in visual acuity during amblyopia treatment. A retrospective analysis was conducted on a cohort of patients with amblyopia, aged 3-14 years old, who visited an outpatient clinic in Shenzhen Eye Hospital between May 2021 and January 2023. The investigation included 105 patients (210 eyes) with isometropic or anisometropic amblyopia. All participants underwent cycloplegic refraction examination and binocular fusion function measurement. All patients underwent standard amblyopia treatment, and those with the best-corrected visual acuity (BCVA) of 0.6 or higher in the amblyopic eye of both eyes received binocular fusion training using a computer platform. A statistically significant negative correlation (-0.263, P=0.007) was observed between the absolute difference in binocular BCVA and binocular fusion function at the start of treatment (baseline). Linear regression analysis revealed that the improvement in BCVA in the amblyopic eye exhibited correlations with several factors, including the baseline binocular BCVA difference, baseline BCVA of the amblyopic eye, improvement in binocular fusion function, and the number of fusion training sessions (regression coefficients: -0.463, -0.771, 0.007, and 0.063, respectively; all P<0.05). Two patterns of binocular fusion function development during treatment were identified using group-based trajectory modeling (GBTM): the slow growth pattern and the rapid growth pattern. The results of a multivariate logistic regression model indicated a statistically significant link between fusion training and the development pattern of binocular fusion function [odds ratio (OR): 5.219, 95% confidence interval (CI): 2.045-13.323]. Enhancing binocular fusion function may result in an improvement of BCVA in the amblyopic eye of patients with amblyopia. The frequency of binocular fusion training is crucial for rapid improvement in binocular fusion function.

Comparison of Three Clinical Stereoscopic Methods for Measuring Binocular Visual Function During Amblyopic Treatment in Unilateral Amblyopia.

This study aimed to compare the measuring stereopsis results of unilateral amblyopia during amblyopic treatment by employing some of the most widely used clinical tests. Thirty-four individuals with previously untreated unilateral amblyopia, aged 8.4 ± 2.7 years, were included in the study. Monocular (best corrected visual acuity [BCVA] at distance) and binocular (including Titmus, Random-dot, and Frisby stereopsis) visual functions were measured at baseline and 2-month and 6-month visits after synthetical treatment. We found that Titmus stereopsis was always significantly better than Random-dot stereopsis (p < 0.001). Frisby stereopsis was also always significantly better than Random-dot stereopsis (p < 0.001). However, there was no significant difference between Titmus stereopsis and Frisby stereopsis (p = 0.562). However, interestingly, there was no significant difference in the mean improvement of the three stereopsis methods from baseline to the 2-month visit, F = 1.158, p = 0.318. Similarly, a significant difference was also lacking in the mean improvement of the three stereopsis methods from baseline to the 6-month visit, F = 0.302, p = 0.740. We conclude that there will be different results obtained from different stereopsis measuring methods used to measure amblyopia in patients. We recommend performing at least two types of stereoscopic measurements to evaluate each case of amblyopia. However, for observing therapeutic effects, each measurement method has the same performance for clinical results during amblyopic treatment.

Visual Performance of People With Albinism Assessed With Generalizable and Adaptive AIM and FInD Methods.

People with albinism (PwA) are known to have visual impairments; however, little is known about whether these functions are disrupted across earlier and later stages of the visual pathway. We investigated distinct perceptual functions and fixation stability within each observer and compared the data with age- (±5years) and sex-matched controls. Twenty-one self-reported PwA and twenty-one controls were recruited. Angular-indication measurement (AIM) and foraging-interactive-D-prime (FInD) psychophysical methods were deployed to measure OS, OD, and OU near visual acuity, spatial contrast sensitivity function (CSF), temporal contrast sensitivity (tCS; 0.5 c/°; horizontal grating: 0, 1, 2, 4, and 8Hz), OU glare acuity, threshold-versus-contrast (2c/° vertical grating), long, medium, and short wavelength cone-isolated color detection, color discrimination, stereoacuity across spatial frequencies (1c/°, 2c/°, 4c/°, 8c/°), horizontal, circular, radial pattern and motion coherence, and equivalent-noise motion detection. Thresholds were determined by AIM and FInD and compared using N-ANOVAs, t-tests, planned multi-comparisons, correlations, and unsupervised, agglomerative hierarchical cluster analysis for each group. We found significant differences between groups for most visual functions except for simple and complex form-coherence (two way-ANOVAs, P > 0.05) and complex motion coherence. Correlations between outcomes revealed more significant correlations for PwA and differences in the specific correlates between groups. Unsupervised hierarchical clustering revealed different functional clusters between groups. AIM and FInD successfully interrogated visual deficits in PwA. Overall, PwA showed impaired performance in achromatic, chromatic, temporal, and binocular functions, and had higher intrinsic noise levels. Midlevel vision was comparable between groups. Unsupervised cluster analysis and correlation between outcomes revealed a difference in functional outcome clusters between groups. The results may help to increase the efficiency of screening and identify target deficits for rehabilitation.

Evaluation of Early Accommodation Outcomes Following Femtosecond Laser-Assisted in situ Keratomileusis and Small Incision Lenticule Extraction

ABSTRACT Purpose The aim of this study is to assess the changes and differences in early postoperative binocular accommodative function following femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE). Methods In this retrospective study, 120 patients (240 eyes) diagnosed with low-to-moderate and high myopia, who underwent either FS-LASIK or SMILE procedures were included. The assessment encompassed measurements of accommodative facility, accommodation time, relaxation time, and accommodation-to-relaxation ratio using a smart flipper. Measurements were taken preoperatively, as well as at 1 day, 1 week, and 1 month postoperatively. Additionally, the visual fatigue scale score was assessed and compared at the 1 month mark post-surgery. Changes in parameters were quantified by calculating the difference between preoperative values and those recorded at each postoperative time point. Results At 1 month post-surgery, both FS-LASIK and SMILE procedures demonstrated potential for recovery or even improvement in accommodative facility, accommodation time, relaxation time, and accommodation-to-relaxation ratio compared to preoperative levels. The FS-LASIK group exhibited a greater magnitude of change in accommodative facility postoperatively compared to the SMILE group. In the low-to-moderate myopia subgroup, the FS-LASIK group exhibited lower changes in accommodation time and visual fatigue scale score at 1 month post-surgery compared to the SMILE group, with all associated p-values <0.05. Conclusions Early postoperative recovery of accommodation function was slower following SMILE compared to FS-LASIK. Additionally, the severity of visual fatigue at 1 month post-surgery was greater in the SMILE group than in the FS-LASIK group. This difference in visual fatigue levels may be attributed to the delayed recovery observed in postoperative SMILE procedures.

Changes to Binocular Vision Function in Exophoric Patients After Experiencing Virtual Reality

Changes to Binocular Vision Function in Exophoric Patients After Experiencing Virtual Reality

Case report: Topical pilocarpine ameliorated the accommodation loss and pupillary dilation after micropulse transscleral laser treatment

BackgroundThe present study elucidates a common significant postoperative complication of micropulse transscleral laser treatment (mTLT) and explores its potential management strategies for younger patients with good central vision.Case presentationThree younger Chinese glaucoma patients with good central vision maintained high intraocular pressures (IOPs) (36, 25, and 30 mmHg) on maximally tolerated topical anti-glaucoma medications. All patients were treated with mTLT because of a higher risk of complications with filtering surgery. After the procedure, their best-corrected visual acuities were not significantly changed, IOPs were significantly decreased, and the number of topical anti-glaucoma medicines was gradually decreased. However, all patients complained about reduced near visual acuity (NVA) for 1–5 months. Slit-lamp examination revealed pupillary dilation, and binocular accommodative function examination indicated accommodation loss. After treatment with 2% topical pilocarpine, all patients reported an improvement in NVA. Among them, we could observe pupillary constriction, recovery of accommodation function, and improved NVA, even discontinuation of pilocarpine in Patient 2.ConclusionIn younger patients with good central vision, topical pilocarpine might ameliorate accommodation loss and pupillary dilation after mTLT.

Visual Performance of Children with Amblyopia after 6 Weeks of Home-Based Dichoptic Visual Training.

This study was aimed at analyzing the efficacy on the improvement of the visual function of a dichoptic online cloud-based platform for the treatment of amblyopia in anisometropic children. A quasi-experimental (pretest-post-test) study was conducted in 23 subjects with ages from 5 to 15 years old with anisometropic amblyopia combined with additional presence (2 subjects) or not (21 subjects) of microtropia. A total of 30 home-based training sessions of 30 min per session with Bynocs® platform were prescribed for 6 weeks. Amblyopic eye logMAR visual acuity (VA) significantly improved from 0.28 ± 0.24 to 0.13 ± 0.20 after the 6-week treatment (p < 0.001). At baseline, 60.9% of participants had VA in amblyopic eye of 0.20 logMAR or worse, whereas this percentage decreased to 21.7% after treatment. Binocular function (BF) significantly improved from 2.82 ± 1.11 to 2.32 ± 0.94 (p < 0.001). Mean compliance was 92%, 87% and 93% at 2, 4 and 6 weeks of treatment, respectively. In conclusion, home-based dichoptic training with the digital platform evaluated is an effective method to improve amblyopic VA and stereoacuity in children with anisometropic amblyopia combined or not with microtropia.

Stability of the angle of deviation in basic intermittent exotropia (IXT) following surgical correction: a retrospective observational study from southern India

ABSTRACT Introduction: Intermittent exotropia (IXT) is commonly seen in areas with more sunlight, females and Asians. Surgical alignment is recommended to improve binocular function, but a high recurrence rate has been reported. This study aimed to assess the stability of ocular alignment and factors contributing to exodrift post-surgery for IXT over 6-month follow-up. Methods: We retrospectively reviewed the medical records of patients with IXT who underwent unilateral recess resect procedures and attended follow-up examinations for at least six months post-surgery. A significant exodrift was defined as exodrift of more than 10PD at distance and near. Ocular deviation, binocularity, and stereopsis at one and six-month post-operative visits were studied to assess the incidence of exodrift post-surgery and the probable factors causing such drift. Results: Of the 50 patients studied, 26 (52%) were males, 42 (84%) were <20 years. The median age at surgery was 10 years (range 6–14), and the median preoperative angle of deviation was 37 PD. Majority of patients (62%) had exodrift within six months of surgery, and about a quarter of the study population had significant exodrift >10 PD. No clinical factors were found to contribute significantly to exodrift in this study.16 (61.5%) patients attained near and distance BSV post-surgery (p-value: <0.001). Six (12%) and 10 (20%) patients with subnormal near and distance stereopsis, respectively, attained normal stereopsis post-surgery. Conclusion: Over half of the patients operated for IXT had some Exodrift, and one-fourth had significant exodrift within six months post-surgery. Despite improved BSV, many patients failed to attain normal stereopsis with just motor alignment.

Prevalence and associated factors of myopia among adolescents aged 12–15 in Shandong Province, China: a cross-sectional study

Myopia is a growing concern worldwide, especially among adolescents. This study aimed to investigate the prevalence and associated factors of myopia in adolescents aged 12–15 in Shandong Province, China. This cross-sectional study adhered to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines and involved stratified random cluster sampling of 128,678 students from 186 middle schools across 17 cities in Shandong Province. Data collection was conducted from March to April 2024. We excluded students with organic eye diseases, abnormal binocular vision functions, or a history of eye injuries or surgeries. Myopia was assessed using the standard logarithmic visual acuity chart and autorefractor without inducing ciliary muscle paralysis. A comprehensive questionnaire survey was conducted to gather demographic characteristics and daily life behaviors. With the chi-squared test for univariable analysis and multivariable logistic regression for identifying significant factors. This study included 126,375 participants, with a gender distribution of 51.02% male and 48.98% female. The overall prevalence of myopia was 71.34%. Higher prevalence was observed in girls (72.26%) compared to boys (70.45%), and the prevalence increased with age, peaking at 73.12% in 15-year-olds. Urban residents had a higher prevalence (71.86%) than rural (70.39%). Factors such as increased frequency of eye usage while lying down or leaning forward, frequent use of eyes while walking or riding in a car, prolonged screen time, and extended homework duration were associated with higher odds of developing myopia. Conversely, higher frequency of outdoor exercise, maintaining proper posture during reading and writing, greater distance from eyes to screen, and longer sleep duration were associated with lower odds. Additionally, female gender, older age, urban residence, and parental history of myopia increased the risk. The high prevalence of myopia among adolescents in Shandong Province was influenced by a combination of demographic, behavioral, and environmental factors. The study highlighted the importance of lifestyle modifications, such as increasing outdoor activities and maintaining proper visual habits, limiting the duration of screen exposure and homework sessions, and extending sleep duration, to mitigate the risk of developing myopia. These findings underscored the need for targeted public health interventions and educational campaigns to address this significant public health issue.

Association of smartphones use, ocular symptoms and binocular dysfunctions in adolescents: a hospital-based cross-sectional study

ABSTRACT Purpose Given the current scenario of increased smartphone use in youth, this study aims to evaluate the proportion of ocular symptoms and binocular dysfunction and their association with smartphone use in adolescents through a hospital-based cross-sectional study. Methods The participants were asked to fill out questionnaires related to smartphone use and symptoms of eyestrain experienced (Balik et al. and Kucer). They were asked about the following seven symptoms: blurring of vision, redness, visual disturbance, secretion, inflammation, lacrimation, and dryness. Each symptom out of the 7, was scored on a scale of 0–1 and was used to calculate an Ocular Symptom Score (OSS) by summing the scores of each symptom.Depending upon the duration of smartphone usage, the participants were classified into four groups: <2 hours/day, 2–4 hours/day, 4–6 hours/day, and >6 hours/day. Binocular functions were assessed using near point of convergence (NPC), near point of accommodation (NPA), Accommodative convergence/Accommodation (AC/A) ratio, dissociated heterophoria, and binocular accommodative facility (BAF). Results A total of 123 smartphone user adolescents, aged 10–19 years were included in this study. The mean age of the study population was 16.58 + 2.8 years, out of which 52.03% were males. Prevalence of ocular symptoms was higher in groups with greater duration of smartphone use (2 to 4, 4 to 6, and >6 hours/day as compared to <2 hours/day: 90.48%, 94.74%, 100% vs. 75% respectively). The mean of NPC was 8.51, it was highest in subjects using smartphones for >6 hours. (p-value = .001). The mean AC/A ratio was 2.83 + 1.03: 1. A low AC/A ratio was associated with a longer duration of smartphone usage (p-value = .0001). The mean of BAF was 7.4 + 3.18 cycles/min, only 30 (24.4%) participants had BAF beyond the normal range (<5 cycles/min). The mean of BAF was lowest in the group with >6 hours/day of smartphone use (p-value < .0001). No significant change was found in NPA and dissociated heterophoria with the duration of smartphone usage. Conclusion Higher duration of smartphone use (>2 hours/day) is associated with various ocular symptoms and binocular dysfunction. However, additional research is necessary to authenticate the results of the study.

Review: Binocular double vision in the presence of visual field loss.

Binocular double vision in strabismus is marked by diplopia (seeing the same object in two different directions) and visual confusion (seeing two different objects in the same direction). In strabismus with full visual field, the diplopia coexists with visual confusion across most of the binocular field. With visual field loss, or with use of partial prism segments for field expansion, the two phenomena may be separable. This separability is the focus of this review and offers new insights into binocular function. We show that confusion is necessary but is not sufficient for field expansion. Diplopia plays no role in field expansion but is necessary for clinical testing of strabismus, making such testing difficult in field loss conditions with confusion without diplopia. The roles of the three-dimensional structure of the real world and the dynamic of eye movements within that structure are considered as well. Suppression of one eye's partial view under binocular vision that develops in early-onset (childhood) strabismus is assumed to be a sensory adaption to diplopia. This assumption can be tested using the separation of diplopia and confusion.

Impact of Online Video Game-Based Dichoptic Training on Binocular Vision Rehabilitation in Post-surgical Patients with Intermittent Exotropia.

Dichoptic training has emerged as a promising rehabilitation approach for improving binocular visual function in patients with strabismus. A prospective observational study design was employed to assess the effectiveness of online video game-based dichoptic training in rehabilitating binocular visual function in patients who had undergone anoperation for intermittent exotropia. A total of 64 patients who had undergone anoperation for intermittent exotropia were recruited and divided into the training group and the control group based on whether they would receive the dichoptic training. The dichoptic training was conducted for 3 months in the training group and the control group would not accept any form of orthoptic therapy. Assessments of binocular visual functions and deviation were conducted at baseline, 3-month and 6-month follow-up. Twenty-nine participants in the training group (mean 9.69 ± 2.66years old) and 26 participants in the control group (mean 8.41 ± 2.64years old) completed follow-up. At both 3- and 6-month follow-ups, the training group showed superior distance stereopsis compared to the control group, with near stereopsis only showing significant difference at the 6-month follow-up. Additionally, the training group exhibited significantly less distance exo-deviation drift than the control group at these times, and no significant difference was observed in near exo-deviation drift between the groups. The control group had a significantly higher rate of suboptimal surgical outcomes at both the 3- and 6-month follow-up. However, no significant differences were observed in simultaneous perception and fusion functions between the two groups. Online video game-based dichoptic training has the potential to become a novel postoperative rehabilitation strategy for patients with intermittent exotropia.

High Magnesium Promotes the Recovery of Binocular Vision from Amblyopia via TRPM7.

Abnormal visual experience during the critical period can cause deficits in visual function, such as amblyopia. High magnesium (Mg2+) supplementary can restore ocular dominance (OD) plasticity, which promotes the recovery of amblyopic eye acuity in adults. However, it remains unsolved whether Mg2+ could recover binocular vision in amblyopic adults and what the molecular mechanism is for the recovery. We found that in addition to the recovery of OD plasticity, binocular integration can be restored under the treatment of high Mg2+ in amblyopic mice. Behaviorally, Mg2+-treated amblyopic mice showed better depth perception. Moreover, the effect of high Mg2+ can be suppressed with transient receptor potential melastatin-like 7 (TRPM7) knockdown. Collectively, our results demonstrate that high Mg2+ could restore binocular visual functions from amblyopia. TRPM7 is required for the restoration of plasticity in the visual cortex after high Mg2+ treatment, which can provide possible clinical applications for future research and treatment of amblyopia.

SPEctacle Correction for the TReatment of Amblyopia (SPECTRA): study protocol for a prospective non-randomised interventional trial in adults with anisometropic/mixed mechanism amblyopia

IntroductionAmblyopia is a neurodevelopmental vision disorder typically affecting one eye, resulting in compromised binocular function. While evidence-based treatments exist for children, there are no widely accepted treatments for adults. This...

The relationship between accommodative and binocular function with myopia progression in myopic children undergoing orthokeratology

PurposeTo determine the relationship between changes in accommodative and binocular function with myopia progression in myopic children over a two-year follow-up period, and to determine when changes in visual functions stabilized after switching from spectacles to orthokeratology (Ortho-K). MethodsThis prospective, self-controlled study followed thirty-six participants (aged 8–14 years) for two years after they switched from spectacles to Ortho-K. Accommodative and binocular function were assessed prior to and 1, 3, 6, 12, 18 and 24 months after commencing Ortho-K. Measurements included accommodative amplitude, accommodative response, accommodative facility, accommodative convergence/accommodation (AC/A), ocular alignment, positive relative accommodation (PRA), negative relative accommodation (NRA), horizontal vergence range, reading ability and stereoacuity. Myopia progression was quantified by the change in axial length. ResultsOcular alignment, monocular and binocular accommodative facility, and PRA stabilized after 1 month. The distance blur point in the convergence range, the distance break and recovery point in the divergence range, accommodative amplitude, calculated AC/A, stereoacuity and reading ability stabilized within 6 months. After two years of Ortho-K, NRA significantly increased (p = 0.044), while it showed no significant difference after one-year of lens wear (p = 0.49). The distance break point in the convergence range showed no significant difference (p = 0.20), but significantly decreased after one-year (p = 0.005). There were no significant correlations between the change in axial length with changes in accommodative or binocular function (p > 0.05). ConclusionAccommodative and binocular function changed significantly after switching from spectacles to Ortho-K and most of the parameters stabilized within the first 6 months. There was no association between the change in accommodative or binocular function and myopia progression.

Experience with Strabologic Surgery on Pediatric Patients with Divergence Excess Exotropia.

This retrospective clinical study evaluates the results of surgical treatment of patients diagnosed with intermittent exotropia of the divergence excess type. The study compares the results of surgery delayed due to the Covid-19 pandemic (patients underwent the surgery after the age of eight), versus a group of younger children. The objective angle of deviation and quality of binocular functions were examined. The follow-up period was six months after surgery. The patients were divided into two groups according to age: 4-7 years and 8-13 years. Each group included 20 patients. The second group comprised patients whose surgery was postponed due to restrictions on elective surgery during the ongoing pandemic. The surgery took place at the University Hospital in Pilsen. Angle of deviation and binocular functions were examined before surgery, postoperatively, and three and six months after surgery. Data were collected retrospectively and statistically processed. The main values were plotted in charts. Accordance between the angle of deviation before surgery in both groups was statistically demonstrated. During the six-month follow-up period, the median angle of deviation was statistically without proof of disparity between the groups. Six months after surgery, an objective angle of deviation within the limit ±5 degrees was achieved in 65% of patients from the first group and in 75% from the second group. Binocular vision before surgery was statistically without proof of difference between both groups. However the statistical processing demonstrated a difference between the two groups six months after the surgery. Better binocular functions were achieved by the younger children in the first group. The objective deviation angle was comparable in both study groups prior to surgery as well as six months after the surgery. The first group of younger patients attained a higher quality of binocular functions within the six-month follow-up period compared to children operated on after the age of eight. This claim was statistically verified.