Binocular Function Research Articles

Effect of Atropine Eye Drops Combined with VR-Based Binocular Visual Function Balance Training for Prevention and Control of Juvenile Myopia.

Purpose This study mainly analyzes the efficacy of 0.01% atropine eye drops (low-dose atropine (LDA)) combined with virtual reality (VR)-based binocular visual function (BVF) balance training in the prevention and control of juvenile myopia. Methods One hundred and thirty-six juvenile myopia patients admitted between November 2018 to November 2021 were selected, including 76 cases (research group) receiving LDA + VR-based BVF balance training and 60 cases (control group) treated by LDA intervention alone. Visual acuity (VA; naked vision), ocular parameters (pupil diameter (PD), axial length (AXL), and diopter), intraocular pressure (IOP), accommodation facility, clinical efficacy, and incidence of adverse reactions were observed, compared, and analyzed in both groups. Results After analysis, it was found that the research group showed significantly higher naked vision and PD while statistically lower D after intervention than the corresponding preinterventional parameters than the control group. While AXL showed no statistical difference between the groups and within groups. The IOP also differed insignificantly between groups, but the post-treatment accommodation facility was better in the research group compared with the baseline (before treatment) and control group. In terms of curative effects, an obviously higher total effective rate was determined in the research group. In addition, the two groups showed no significant difference in the incidence of adverse reactions. Conclusions LDA + VR-based BVF balance training deserves clinical popularization, as it can prevent and control myopia among teenagers, with better adjusting effects on eye function and certain safety.

Analysis of the Changes and Possible Reasons in Aberrations before and after Surgery in Patients with Concomitant Exotropia.

Objective The objective is to observe the changes in aberrations before and after surgery in patients with common horizontal strabismus and to analyze the possible reasons for the changes. Methods Forty eyes of 40 cases with concomitant exotropia who underwent strabismus correction at the Ophthalmology Department of Nantong University Hospital from October 2020 to July 2021 were included in this study, all of whom underwent unilateral lateral rectus recession combined with a medial rectus resection in the same eye. Aberration parameters were measured 1 day before surgery and 1 week, 1 month, 3 months, and 6 months after surgery. Differences in the indicators at each time period were compared by analysis of variance (ANOVA) of repeated measures data for a single factor, and data were analyzed using SPSS 25.0 statistical application software. Results 5 mm pupil diameter: the preoperative and postoperative RMS of total aberration showed statistically significant difference (P < 0.01). Postoperation test (Bonferroni method) and preoperative comparison at each period after surgery showed statistically significant differences between 6 months after surgery (P=0.002) and preoperative comparison. The preoperative and postoperative comparison of RMS in LOAs was statistically significant (P < 0.01); postoperative test (Bonferroni method) and preoperative comparison showed that there were statistically significant differences between 1 week (P=0.033) and 6 months (P=0.002) after operation. The difference of RMS of defocus before and after operation was statistically significant (P < 0.01); postoperation test (Bonferroni method) and preoperative comparison showed that there was statistically significant difference between 6 months after operation (P=0.007) and preoperative comparison. There was statistically significant difference in preoperative and postoperative RMS of HOAs (P=0.013). Postoperative test (Bonferroni method) and preoperative comparison showed that there was statistically significant difference 6 months after surgery (P=0.03). The RMS of secondary astigmatism showed a statistically significant difference before and after operation (P=0.001), and the postoperation test (Bonferroni method) showed a statistically significant difference 6 months after operation (P=0.002). In 5 mm pupil diameter, the preoperative and postoperative RMS of total aberration showed statistically significant difference (P < 0.01), postoperative test (Bonferroni method) was used to compare each period after surgery with that before surgery, and there were statistically significant differences between 1 week after surgery (P=0.034), 3 months after surgery (P=0.033), and 6 months after surgery (P=0.003). The preoperative and postoperative comparison of RMS in LOAs was statistically significant (P < 0.01), postoperative test (Bonferroni method) was used to compare each period after surgery with that before surgery, and there were statistically significant differences between 1 week after surgery (P=0.04), 3 months after surgery (P=0.034), and 6 months after surgery (P=0.004). The difference of RMS of defocus before and after surgery was statistically significant (P=0.002), and the comparison between postoperation test (Bonferroni method) and preoperation showed that the difference was statistically significant 6 months after surgery (P=0.027). The RMS of astigmatism showed statistically significant difference before and after operation (P=0.002), and the postoperation test (Bonferroni method) showed statistically significant difference between 6 months after operation (P=0.009) and before operation. Conclusion We found that horizontal rectus surgery had a transient effect on LOAs and almost no effect on HOAs. Long-term follow-up is recommended after strabismus surgery to observe eye position and binocular visual function. Because of the high prevalence of strabismus in adolescents, long-term observation of the eye axis and aberration is recommended.

Binocular Summation of Visual Acuity at High and Low Contrast in Early Glaucoma.

This study examined the integrity of binocular summation function in patients with mild glaucoma. We found that binocular summation of visual acuity is preserved in these patients, despite their reduced monocular inputs. Binocular summation represents superiority of binocular to monocular performance. In this study we examined the integrity of binocular summation function in patients with early glaucoma who had structural glaucomatous changes but otherwise had no significant interocular acuity asymmetry or other functional deficit detected with standard clinical measures. Participants included 48 patients with early glaucoma according to Hodapp, Anderson, and Parrish 2 (HAP2) criteria (age 65±12y) and 42 healthy controls (age 60±12y), matched for stereoacuity. Visual acuity was assessed binocularly and monocularly at high (95%) and low (25%) contrast using the Early Treatment Diabetic Retinopathy Study (ETDRS) charts at 6m. Binocular acuity summation was evaluated utilizing a binocular ratio (BR). Overall, binocular and monocular visual acuity of the control group was better than that of the glaucoma group for both contrast levels, P =0.001. For the glaucoma group, there was a significant difference between BRs at high and low contrast, 0.01±0.05 and 0.04±0.06 ( P =0.003), respectively. For the control group, the difference between BR at high and low contrast was not statistically significant, 0.00±0.07 and 0.02±0.06 ( P =0.25), respectively. For patients with early glaucoma, binocular summation function for visual acuity was preserved at both contrast levels. This suggests an adaptation of the visual system in early stages of glaucoma that allows for normal binocular summation in the presence of reduced monocular visual input.

Amblyopia and fixation eye movements

Amblyopia is a neurodevelopmental disorder caused by abnormal visual experience in early life that affects 3–5% of the population. Amblyopia results in a host of monocular and binocular visual afferent function deficits including reduced visual acuity, contrast sensitivity, depth perception, interocular suppression, and efferent function abnormalities such as unstable and inaccurate fixation. Conventional treatments such as patching therapy and newer dichoptic treatments are not always successful as 30–40% of patients experience recurrence/regression of amblyopia. There are numerous review articles focused on visual afferent function deficits and treatment modalities and outcomes in amblyopia. Recently, the advent of high spatial and temporal resolution eye trackers has spurred studies on fixation eye movements (FEMs) in healthy controls and neurologic and ophthalmic disorders. In this focused review, we will summarize studies evaluating FEM abnormalities in amblyopia. We will first describe the common devices and techniques used to quantify fixation abnormalities, and then highlight the importance of systematically evaluating the eye movements under different viewing conditions and describe the parameters crucial in assessing FEM abnormalities in amblyopia. We will summarize the evidence suggesting that FEM abnormalities are not limited to the amblyopic eye only but also affects the fellow eye and that FEM abnormalities can serve as biomarkers to predict the impact of amblyopia on visual functions. Beyond diagnosis, we will discuss the treatment and prognostic implications of the evaluation of FEM abnormalities in clinical practice.

Stereopsis in the Infant Aphakia Treatment Study: comparison between ages 4½ and 10½

Infants born with a unilateral congenital cataract (UCC) are frequently unable to perceive depth based on binocular cues because of the patching regimen employed to ensure optimal vision in the treated eye, as well as the disparity in acuity between their eyes. At the 4½ year visual assessment approximately 25% of the IATS patients demonstrated some level of binocular functioning. We determined that retesting stereopsis at age 10½ years would provide valuable information.

Pattern Strabismus in a Tertiary Hospital in Southern China: A Retrospective Review.

Background and objectives: To analyze demographic and clinical features of pattern strabismus patients and assess the relationship among these clinical variables and risk factors. Materials and Methods: Medical records of pattern strabismus patients who had undergone strabismus surgery at our center between 2014 and 2019 were retrospectively reviewed. Data collected included gender, age at onset, age at surgery, refraction, Cobb angle, pre- and post-operative deviations in the primary position, up- and downgaze, angle of ocular torsion, type/amount of pattern, grade of oblique muscle function and presence/grade of binocular function. To verify the clinical significance of the Cobb angle, 666 patients who had undergone surgery within one week after ocular trauma between 2015 and 2021 were enrolled as controls. Results: Of the 8738 patients with horizontal strabismus, 905 (507 males and 398 females) had pattern strabismus, accounting for 10.36%. Among these 905 patients, 313 showed an A-pattern and 592 showed a V-pattern. The predominant subtype was V-exotropia, followed by A-exotropia, V-esotropia and A-esotropia. Over half of these patients (54.6%) manifested an A- or V-pattern in childhood. The overall mean ± SD Cobb angle was 5.03 ± 4.06° and the prevalence of thoracic scoliosis was 12.4%, both of which were higher than that observed in normal controls (4.26 ± 3.36° and 7.8%). Within A-pattern patients, 80.2% had SOOA and 81.5% an intorsion, while in V-pattern patients, 81.5% had IOOA and 73.4% an extorsion. Patients with binocular function showed decreases in all of these percent values. Only 126 (13.9%) had binocular function, while 11.8% of A-pattern and 15.1% of V-pattern patients still maintained binocular function. Pre-operative horizontal deviation was negatively correlated with binocular function (r = −0.223, p < 0.0001), while the grade of oblique muscle overaction was positively correlated with the amount of pattern (r = 0.768, p < 0.0001) and ocular torsion (r = 0.794, p < 0.0001). There were no significant correlations between the Cobb angle and any of the other clinical variables. There were 724 patients (80.0%) who had received an oblique muscle procedure and 181 (20.0%) who received horizontal rectus muscle surgery. The most commonly used procedure consisted of horizontal rectus surgery plus inferior oblique myectomy (n = 293, 32.4%), followed by isolated horizontal rectus surgery (n = 122, 13.4%). Reductions of pattern were 14.67 ± 6.93 PD in response to horizontal rectus surgery and 18.26 ± 7.49 PD following oblique muscle surgery. Post-operative deviations were less in V- versus A-pattern strabismus. Post-operative binocular function was obtained in 276 of these patients (30.5%), which represented a 16.6% increase over that of pre-operative levels. The number of patients with binocular function in V-pattern strabismus was greater than that of A-pattern strabismus (p = 0.048). Conclusions: Of patients receiving horizontal strabismus surgery, 10.36% showed pattern strabismus. In these patients, 54.6% manifested an A- or V-pattern in childhood, and V-exotropia was the most frequent subtype. Pattern strabismus patients showed a high risk for developing scoliosis. Cyclovertical muscle surgery was performed in 724 of these patients (80.0%), and horizontal rectus surgery was effective in correcting relatively small levels of patterns. Binocular function represented an important factor as being involved with affecting the occurrence and development of pattern strabismus.

Binocular treatment for individual with amblyopia: A systematic review and meta-analysis.

Objective:To assess the efficacy of binocular treatment for individual with amblyopia.Methods:In this meta-analysis, a comprehensive search of literatures was performed from PubMed, Embase, Cochrane Library and Web of Science databases up to December 21, 2020. Sensitivity analysis was performed for all outcomes. The Begg’s test was used to assess the publication bias. Heterogeneity test was conducted for each effect indicator. Indicators were analyzed by random-effects model when the heterogeneity statistic I2 ≥ 50%, on the contrary, indicators were analyzed by fixed-effect model. Standard mean difference (SMD) or weighted mean difference (WMD) was adopted as effect indicators, and the effect amount was expressed as 95% confidence intervals (CIs).Results:A total of 13 literatures including 1146 participants were finally enrolled, with 595 in the intervention group and 551 in the control group. The results indicated that the improvement of amblyopic eye visual acuity [SMD: 0.882, 95%CI: (0.152, 1.613), P = 0.018] in binocular treatment group was better than that in control group. And binocular treatment could improve stereo acuity in individual with amblyopia [WMD: 0.138, 95%CI: (0.068, 0.208), P < 0.001].Conclusion:Binocular treatment may be beneficial to visual acuity, stereo acuity and binocular function improvement for individual with amblyopia. In clinical practice, binocular treatment can be used as one of the treatments for individual with amblyopia.

Long-Term Efficacy of the Combination of Active Vision Therapy and Occlusion in Children with Strabismic and Anisometropic Amblyopia.

This retrospective study was conducted to evaluate the efficacy of the combined treatment of occlusion and active vision therapy in a total of 27 amblyopic children, including 14 strabismic and 13 anisometropic cases. For such purpose, changes in distance and near visual acuity as well as in the binocular function was evaluated during a two-year follow-up. In both amblyopia groups, significant improvements were found in distance and near visual acuity in the non-dominant eye (p < 0.001). In the strabismic amblyopia group, the percentage of patients with binocular function score (BF) > 3.3 decreased significantly from a baseline value of 64.3% to a two-year follow-up value of 7.1% (p < 0.001). In the anisometropic amblyopia group, this percentage also decreased significantly from a baseline value of 15.4% to a two-year follow-up value of 0.0% (p < 0.001). No recurrences were observed in the anisometropic amblyopia group, whereas recurrence occurred in two cases of the strabismic amblyopia group after finishing the vision rehabilitation process. In conclusion, the combined approach of the treatment evaluated is efficacious for providing an improvement in visual acuity and binocular function in both anisometropic and strabismic amblyopia, which was maintained over time.

Visual disorders in patients with dyslexia (literature review)

Background.The ability to read is the key to successful education of schoolchildren and students. At the same time, according to various authors, from 5–10 to 20–30% of the population experience difficulties, characterized as “reading below the level of language proficiency”, “reading difficulties” and “dyslexia”. This work is devoted to the analysis of modern Russian and foreign literature in the field of aetiopathogenesis, diagnosis, clinical manifestations and functional correction of visual disorders in dyslexia.Aim:to study the literature data on visual impairment in patients with dyslexia.Materials and methods.The literature analysis of publications available on PubMed, eLibrary, CyberLeninka and Crossref Metadata Search was carried out.Results.The conducted analysis demonstrates the importance of effective detection of visual disorders in patients with dyslexia, which is necessary for a correct comprehensive assessment of this condition, as well as understanding the causes and nature of difficulties experienced by a child with dyslexia in the process of learning to read. The results of the analysis of studies reveal the possibilities of positive dynamics in the development of reading skills in patients with dyslexia in the process of functional treatment aimed at developing binocular visual functions, improving the functioning of the oculomotor system and the accommodation.Conclusion.The authors conclude that an in-depth ophthalmic examination and treatment of the identified ophthalmic pathology is of great importance in the overall complex of diagnostic and corrective measures in patients with dyslexia.

Most nonpathological eyes present a small area of hyperreflective Henle's fiber layer on pupil-centered optical coherence tomography.

Henle's fiber layer (HFL) is hyporeflective and indistinct on pupil-centered optical coherence tomography (OCT). However, a small area of HFL is also found to be hyperreflective on pupil-centered OCT. This study characterized the hyperreflective HFL of healthy eyes on pupil-centered OCT and investigated the possible physiological and functional relationship of hyperreflective HFL. Subjects with different degrees of ametropia underwent a complete ophthalmologic examination, including binocular function by synoptophore and Titmus test, ocular axial length, refractions, and pupil-centered OCT angiography coupled with OCT. The area of hyperreflective HFL was manually plotted and calculated using the Optovue AngioVue system technology. The possible ocular physiological and functional relationship with the area of hyperreflective HFL was investigated. A total of 111 subjects (222 eyes) without other ocular diseases were enrolled, of which 164 eyes (74%) presented hyperreflective HFL. The average area of hyperreflective HFL was 0.71 ± 0.07mm2. The area of hyperreflective HFL was significantly related to spherical diopters (P = 0.032). The average binocular area of hyperreflective HFL was 1.38 ± 0.17mm2. The binocular area of hyperreflective HFL was significantly related to the angle of superposition and far stereoacuity (P = 0.013 and 0.038, respectively). Most healthy eyes present a small area of hyperreflective HFL, which might be due to alternation of the orientation of some Henle fibers by ametropia during the development of visual function postpartum. The small area of hyperreflective HFL may serve as a marker in identifying the boundary of HFL on OCT.

Multi-modal Treatment Approach Incorporating Vision Therapy and Syntonics for Combined Organic and Functional Amblyopia

Background: Amblyopia is characterized by reduced visual acuity along with compromised binocular visual function. Form deprivation amblyopia is obstruction of light which prevents visual development. It is has traditionally been managed at an early stage of life through occlusion therapy. Case Summary: A 32-year-old male was diagnosed with acquired form deprivation strabismic amblyopia. Ocular trauma resulted in post pupilloplasty with membranectomy surgery of the right eye, and pseudophakia of the right eye, while the posterior segment was within normal limits. Stereopsis was absent. In-office and home vision therapy was implemented, which included syntonic phototherapy, space fixator, and monocular fixation in binocular field and Ambi-iNet. Conclusion: A multi-modality approach in treatment improved vision and stereopsis for an adult with acquired form deprivation strabismic amblyopia secondary to traumatic cataract, occlusio pupillae, and traumatic angle closure glaucoma.

Prismatic treatment of acute acquired concomitant esotropia of 25 prism diopters or less

BackgroundThis study aimed to assess the efficacy of prismatic treatment in a step-by-step manner to reduce prismatic strength in acute acquired concomitant esotropia (AACE) of 25 prism diopters (PD) or less.MethodsIn this retrospective comparative study, 36 patients with AACE with deviation angle ≤ 25 PD were treated with Fresnel prism in a step-by-step manner to reduce prismatic strength. The patients were divided into two groups according to whether they regained orthophoria and were weaned off the press-on prisms within 1 year: (1) the treatment-success group, which consisted of patients who had their esotropia eliminated and were weaned off the press-on prisms within 1 year after prism correction, and (2) the treatment-continuing group, which comprised patients who needed to continue wearing a Fresnel prism at 1 year after the beginning of prismatic correction because diplopia and esotropia still existed. Clinical characteristics and cooperation were analyzed and compared between groups.ResultsFourteen of 36 patients (38.9%) were weaned off the prism and regained orthophoria and binocular single vision within 1 year after prismatic treatment. Compared with the treatment-continuing group, the treatment-success group showed smaller deviation at near and distant fixations (P = 0.024 and P = 0.006, respectively) measured at the beginning of prismatic correction, a shorter time from onset to prismatic treatment (P = 0.02), and a greater percentage of patients exhibiting good cooperation (P < 0.001).ConclusionsPrismatic treatment in a step-by-step manner to reduce prismatic strength can lead to good outcomes of motor alignment and binocular function in patients with AACE of 25 PD or less. Patients showing good cooperation, smaller angle of esotropia, and shorter duration from onset to treatment tend to eliminate esotropia and be weaned off press-on prisms within 1 year after prismatic correction.

Evaluation of the Efficacy of a New Dichoptic Digital Platform to Treat the Anisometropic and Isometropic Amblyopia.

The aim of the current study was to evaluate the results of a novel dichoptic training program using an online platform in a group of subjects with refractive amblyopia, performing a comparative analysis of unilateral and bilateral amblyopic cases. For this purpose, a retrospective study analysis of data of 161 children (4–13 years) who underwent dichoptic treatment with the Bynocs® platform (Kanohi Eye Pvt. Ltd., Mumbai, India) was performed. In all cases, the therapy protocol consisted of sessions of training of 30 min daily 5 times a week for 6 weeks. Best corrected visual acuity (BCVA) in the non-dominant eye improved significantly with the treatment, with a mean change of 0.39 logMAR in the whole sample (p < 0.001). Regarding binocularity, the binocular function (BF) score also experienced a significant improvement (p < 0.001), with a mean change of 1.55 with therapy in the whole sample. The BCVA of the dominant eye only improved significantly (p < 0.001) in the isometropic amblyopic subgroup. In conclusion, the use of the dichoptic therapy with the digital platform evaluated allows an effective restoration of visual acuity and binocular function in children with anisometropic and isometropic amblyopia.

Changes in Accommodative and Binocular Function following Phakic Intraocular Lens for High and Low-to-Moderate Myopia.

The aim was to evaluate accommodative and binocular function of phakic intraocular lens implantable collamer lens (ICL) in high and low-to-moderate myopia. Prospective comparative cohort study with 38 myopic patients who underwent ICL implantation were divided into two groups of 19 patients, each one based on the spherical equivalent (SE): high-power (SE ≤ −6 D) and low-to-moderate (SE > −6 D). The push-up amplitude of accommodation (AA), monocular accommodative facility (MAF), distance and near ocular deviation, near convergence amplitude, near point convergence (NPC), stereopsis, and accommodative convergence/accommodation (AC/A) ratio were assessed before surgery and 1 week and 1 month postoperatively. The mean residual refractive error at 1 month after surgery improved in both groups, 0.18 ± 0.34 D and 0.09 ± 0.26 D, respectively (p < 0.001). There was a significant decrease in AA in both groups between preoperatively and at 1-week (p = 0.001; p = 0.008, respectively) and 1-month follow-up (p = 0.001; p = 0.008). For the rest of the binocular measurements, no statistically significant postoperative changes were found in any group. This finding suggests follow-up studies on amplitude of accommodation in phakic intraocular lens ICL implantation.

Correlating Ocular Physiology and Visual Function with Mild Cognitive Loss in Senior Citizens in Taiwan.

Purpose: The transition of Taiwan from an aging to a super-aging society has come with a cost as more elderly now suffer from cognitive impairment. The main purpose of our study was to investigate if early detection can be developed so that timely intervention can be instituted. We analyzed the correlation of cognitive function with ocular physiology and visual functions between senior citizens aged 60 years or older in Taiwan. Methods: Thirty-six healthy subjects were recruited for the study. Addenbrooke’s cognitive examination III (ACE-III), binocular functions (including objective and subjective refraction, distance and near dissociated phoria, stereopsis, contrast sensitivity, adult developmental eye movement (ADEM), and ocular physiology (by using optical coherence tomography, OCT, and macular pigment measurement, MPS) were performed, and the data were analyzed via independent t-test, chi-square test, Pearson correlation, linear regression, and ROC (receiver operating characteristic) curve. Results: Data analysis showed that (1) patients with poor eye movement had a strong correlation with the total score and all dimensions of cognitive functions, (2) the thickness of the macula had a strong correlation with attention and memory, and (3) patients with poor eye movement and poor stereopsis in combination with thinner inferior macula appeared to have lower cognitive abilities. Discussion and Conclusions: Cognitive dysfunction is not readily identified during the early stage of cognitive decline. The use of simple and inexpensive ADEM or stereopsis test and comparing the OCT results that are popular in optometry clinics for reference can be diagnostic in identifying patients with mild cognitive impairments. With the combined use of macular pigment density or retinal thickness measurements, it was possible to effectively predict the early degradation of cognition.

Recent understanding of binocular vision in the natural environment with clinical implications.

Technological advances in recent decades have allowed us to measure both the information available to the visual system in the natural environment and the rich array of behaviors that the visual system supports. This review highlights the tasks undertaken by the binocular visual system in particular and how, for much of human activity, these tasks differ from those considered when an observer fixates a static target on the midline. The everyday motor and perceptual challenges involved in generating a stable, useful binocular percept of the environment are discussed, together with how these challenges are but minimally addressed by much of current clinical interpretation of binocular function. The implications for new technology, such as virtual reality, are also highlighted in terms of clinical and basic research application.

Binocular Function in Different Gaze Positions.

PurposeTo evaluate varied aspects of binocular function in multiple gaze positions.MethodsIn 2018, this cross-sectional study was conducted on 21 participants (male = 11) with an age range of 19–25 years. Having emmetropia and 10/10 visual acuity in both eyes were conditions of the inclusion criteria for the cross-sectional study. The following aspects of binocular function including amplitude of accommodation (AA), near point of convergence, near phoria, and monocular accommodative facility were evaluated in five gazes (primary, upward, downward, left, and right) for all subjects.ResultsNear point of convergence values showed significant differences in all gaze positions (P 0.001). The lowest near point of convergence value was seen in the primary gaze (2.69 cm) and the downward gaze (3.47 cm) and the highest near point of convergence value was seen in the left gaze (7.5 cm). There was also a significant difference in the amplitude of accommodation among the upward, downward, and the primary gaze (P 0.001) positions but no difference was observed among the temporal, nasal, and the primary gaze positions. There was a significant difference in near phoria between the upward gaze and the primary gaze (P = 0.008) while no significant differences were observed among the other gazes. There was no significant variance in the monocular accommodative facility among the different gaze positions (P = 0.175).ConclusionThe results of this study indicated variations that exist in the convergence and accommodation reflex functions in multiple gaze positions, which proved to be more prominent in the convergence system. Although the accommodative sufficiency evaluation was inconsistent among the multiple gaze positions, the accommodative facility evaluation was consistent in all gazes.

Measuring aniseikonia and investigating neuroplasticity and image factors in amblyopia (MAGNIFY): study protocol for a randomised clinical trial

BackgroundAniseikonia represents a potential barrier to neuroplasticity which may limit visual outcomes in children with anisometropic amblyopia. Full correction of refractive error is the first step in standard amblyopia treatment, which corrects for image focus but neglects image size differences.MethodsThe MAGNIFY study is a double-masked, randomised clinical trial investigating the effectiveness of aniseikonia correcting lenses in children at first diagnosis of significant anisometropia. We hypothesis that aniseikonia correction lenses will improve image clarity and reduce the retinal size differences producing better visual acuity and stereoacuity improvements after 15 weeks of optical treatment for children with anisometropia. Eligible children will be randomly allocated to the treatment group (aniseikonia-correcting spectacle lenses) or control group (standard spectacle lenses). Visual acuity and binocular functions will be assessed every 5 weeks during the 15-week optical treatment phase according to standard amblyopia treatment protocol.DiscussionIt is possible that correcting aniseikonia along with anisometropia at first diagnosis will promote binocularity as well as increase spectacle adherence by reducing visual discomfort, improving optical treatment outcomes. This could then reduce the need for additional amblyopia treatment such as patching or atropine, reducing the burden on hospital eye departments and potentially improving visual outcomes for children with amblyopia.Trial registrationAustralian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12620000061932. Registered on 24 January 2020. Protocol 15th November 2019, version one.

Virtual reality-based vision therapy versus OBVAT in the treatment of convergence insufficiency, accommodative dysfunction: a pilot randomized controlled trial

BackgroundVirtual reality is being increasingly applied in vision therapy. However, the differences in effectiveness, optimal treatment cycle, and prognosis between virtual reality-based vision therapy and traditional therapies remain unknown. The purpose of this study was to compare the effectiveness of virtual reality-based vision therapy and office-based vergence/accommodative therapy in young adults with convergence insufficiency or accommodative dysfunction.MethodsThe patients were randomly assigned to either the virtual reality-based vision therapy group or the office-based vergence/accommodative therapy group. The vision therapy lasted 12 weeks (1 h/week) in both groups. Binocular visual functions (vergence and accommodation) were measured and a subjective questionnaire-based assessment was performed at baseline and after 6 and 12 weeks of therapy.ResultsIn total, 33 patients with convergence insufficiency and 30 with accommodative dysfunction completed the study. After 12 weeks of treatment for convergence insufficiency, the Convergence Insufficiency Symptom Survey score (F2,31 = 13.704, P < 0.001), near point of convergence (F2,31 = 21.774, P < 0.001), positive fusional vergence (F2,31 = 71.766, P < 0.001), and near horizontal phoria (F2,31 = 16.482, P < 0.001) improved significantly in both groups. Moreover, the monocular accommodative amplitude (F2,25 = 22.154, P < 0.001) and monocular accommodative facility (F2,25 = 86.164, P < 0.001) improved significantly in both groups after 12 weeks of treatment. A statistically significant difference was observed in monocular accommodative facility (F1,25 = 8.140, P = 0.009) between the two groups, but not in other vergence and accommodative functions (0.098 < P < 0.687).ConclusionVirtual reality-based vision therapy significantly improved binocular vision functions and symptoms in patients with convergence insufficiency and accommodative dysfunction, thereby suggesting its effectiveness as a new optional or additional treatment for young adults with these conditions.Trial registrationThis study was registered at the Chinese Clinical Trials Registry on 16/04/2019 (identifier: ChiCTR1900022556).

The influence of contact lenses with different optical designs on the binocular vision and visual behavior of young adults

Theoretically, contact lenses change the accommodation and vergence demands of the eyes and directly or indirectly influence binocular vision. The purpose of this study was to investigate the influence of different optical designs of contact lenses on binocular vision and visual behavior among young adults. In this randomized, single-blinded experimental study, visual behavioral performance (VBP) and Ocular Surface Disease Index questionnaires were used for preliminary screening. Nineteen myopic subjects aged 20–26 years (21.59 ± 1.40 years) participated in the study. Baseline values for subjective refraction and binocular visual functions were evaluated. All the subjects were randomly grouped to wear different optical designs of single-vision, progressive, and bifocal contact lenses. Eye examinations were performed on the first day (CL baseline), 2nd week, and 4th week of wearing the lenses. In addition, subjects completed the VBP and visual quality questionnaire again at the end of the examination. Single-vision contact lenses (Lens 1) increased accommodative lag, negative relative accommodation, and distant and near vergence; however, vergence facilities, accommodative facilities, heterophoria, and the comfort and posture balance dimensions in the VBP questionnaire were improved. Progressive contact lenses (Lens 2) reduced the lag of accommodation and near vergence; in addition, vergence facilities and accommodative facilities were also improved. Bifocal contact lenses (Lens 3) affected negative and positive relative accommodation, but vergence facilities and accommodative facilities also progressed. Furthermore, both progressive (Lens 2) and bifocal (Lens 3) contact lenses enhanced overall visual behavioral performance. In terms of visual quality, single-vision contact lenses (Lens 1) were the most comfortable, progressive and bifocal contact lenses reduced distant visual acuity and stability, progressive contact lenses (Lens 2) had more complaints about halos at night, and bifocal contact lens (Lens 3) users were more likely to have double vision. Compared with single-vision contact lenses, progressive and bifocal contact lenses relaxed accommodation, reduced the lag of accommodation, and improved visual behavioral performance. Although the vergence function showed a significant change, it did not show worse trends when wearing contact lenses. Contact lenses with different optical designs have a great influence on binocular vision and visual behavioral performance.