Results of fusional vergence therapy in managing consecutive esotropia: A case series

Purpose: To analyze the efficacy of fusional vergence therapy (FVT) in management of consecutive esotropia with diplopia after intermittent exotropia (IXT) surgery. The current study is carried on how FVT affects the duration of treatment, sensory fusion, and exotropic drift. Methods: This was a retrospective study for the medical record of 11 patients with consecutive esotropia after IXT surgery of 543 patients over the period of 5 year, with mean surgery age of 9.5 (range: 4–33 y). FVT was planned after minimum 6 weeks of surgery and was considered for maximum 24 weeks. Patients underwent a combination of office-based and home-based FVT. Successful outcome of therapy was considered where diplopia resolves in free space and achieves sensory fusion, stereopsis with no manifest deviation. Results: Record of 543 patients who had horizontal muscle surgery for IXT were identified and reviewed. Records of 11 patients who showed consecutive esotropia of 10 prism diopter (PD) or more with normal retinal correspondence, with or without diplopia complaint, after 6 week of surgery and had undergone vision therapy management were reviewed. A successful outcome of binocular single vision with good sensory and motor fusion with no manifest deviation or prism requirement was achieved with in the mean duration of 4.8 month of therapy. With a mean duration of 4 weeks of therapy, the mean angle of deviation reduced by 53% for distance (17 PD to 8 PD) and 27% for near (11 PD to 8 PD) and mean stereopsis improvement by 80% with 94% patients demonstrating sensory fusion on Bagolini test and 94% of patients having no symptoms of diplopia or squint. Conclusion: With nonsurgical management involving refractive error correction, FVT, and prism, consecutive esotropia was resolved in 74% cases. Management of consecutive esotropia with FVT can result in satisfactory sensory fusion and successful motor alignment.

Vergencias fusionales. Exploración e importancia en la práctica clínica / Fusion Vergences. Exploration and Importance in Clinical Practice

La vergencia fusional se define como la vergencia estimulada por la disparidad retiniana que genera un movimiento vergencial para mantener la visión binocular simple, son movimientos binoculares disyuntivos en los que ambos ojos se dirigen en la misma dirección para fijar un objeto y a la vez se desplazan en sentido opuesto. La amplitud de fusión desempeña un importante papel en mantener una visión binocular simple. Los valores fuera de la norma son significativos en el diagnóstico de posibles disfunciones binoculares no estrábicas. Con este artículo se pretende mostrar los diferentes criterios relacionados con la evaluación de la amplitud de las reservas fusionales, cual es la prueba más usada y los rangos considerados dentro de límites normales, para lo que se realizó una búsqueda en diferentes publicaciones y textos de la especialidad(AU)

Fusional vergence is defined as the vergence stimulated by retinal disparity that generates a vergence movement to maintain simple binocular vision, they are disjunctive binocular movements in which both eyes are directed in the same direction to fix an object and at the same time they move in opposite way. Fusion amplitude plays an important role in maintaining single binocular vision. Values outside the norm are significant in the diagnosis of possible non-strabismic binocular dysfunctions. This article aims to show the different criteria related to the evaluation of the amplitude of fusional reserves, which is the most used test and the ranges considered within normal limits, for which a search was carried out in different publications and texts of the specialty(AU)

Non - strabismic binocular vision anomalies among students of a Malaysian private university uses visual display unit / 国际眼科杂志(Guoji Yanke Zazhi)

?AIM: To determine the status of non - strabismic binocular vision anomalies ( NSBVA) among students of a Malaysian private university uses visual display units ( VDU) .?METHODS: A cross- sectional study was conducted among university students who use VDU 3h or more from January 2019 to May 2019. A convenient sampling method was utilized. All subjects had gone through primary eye-examinations to satisfy the inclusion criteria. Those who satisfy the inclusion criteria, further gone through the NSBVA assessment. The descriptive analysis was done to rule out the percentage of NSBVA and Chi-square test of independence was carried out to observe the association of NSBVA with age, gender and hours of VDU usage.?RESULTS: A total of 140 students including 88 females ( 62. 9％) and 52 males ( 37. 1％) participated in this study. The mean age of the participants was 22. 54 ± 1. 48 years and the mean VDU usage hours were 5. 76 ± 2. 49h. The percentage of NSBVA is 40％ among the students those who use VDU. The occurrence of accommodative and vergence anomalies among the VDU users is 17. 86％ and 22. 14％ respectively. There was a moderate association between gender and NSBVA (P=0. 010). However, there was no significant association observed for age ( P =0. 334) and hours of VDU usage ( P=0. 835) with NSBVA.?CONCLUSION:NSBVA is 40％ among the students of a Malaysian private university uses VDU. Accommodation insufficiency ( 15％) and convergence insufficiency ( 10％) is more common among all NSBVA for VDU users.

Non-strabismic binocular vision anomalies among students of a Malaysian private university uses visual display unit / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To determine the status of non-strabismic binocular vision anomalies(NSBVA)among students of a Malaysian private university uses visual display units(VDU).<p>METHODS: A cross-sectional study was conducted among university students who use VDU 3h or more from January 2019 to May 2019. A convenient sampling method was utilized. All subjects had gone through primary eye-examinations to satisfy the inclusion criteria. Those who satisfy the inclusion criteria, further gone through the NSBVA assessment. The descriptive analysis was done to rule out the percentage of NSBVA and Chi-square test of independence was carried out to observe the association of NSBVA with age, gender and hours of VDU usage.<p>RESULTS: A total of 140 students including 88 females(62.9%)and 52 males(37.1%)participated in this study. The mean age of the participants was 22.54±1.48 years and the mean VDU usage hours were 5.76±2.49h. The percentage of NSBVA is 40% among the students those who use VDU. The occurrence of accommodative and vergence anomalies among the VDU users is 17.86% and 22.14% respectively. There was a moderate association between gender and NSBVA(<i>P</i>=0.010). However, there was no significant association observed for age(<i>P</i>=0.334)and hours of VDU usage(<i>P</i>=0.835)with NSBVA. <p>CONCLUSION: NSBVA is 40% among the students of a Malaysian private university uses VDU. Accommodation insufficiency(15%)and convergence insufficiency(10%)is more common among all NSBVA for VDU users.

Binocular vision problems associated with refractive surgery and the use of risk screening / 中华实验眼科杂志

Although binocular vision problems do not appear to be one of the common complications of refractive surgery, the available evidence suggests that these problems can occur after refractive surgery, and preoperative binocular vision status may predict the risk of postoperative binocular vision anomalies.Furthermore, because ophthalmologists usually do not clearly recognize binocular vision, or they do not pay enough attention to it, the existing literature may underestimate the actual prevalence of binocular vision problems after refractive surgery.This paper discusses the existing literature on refractive surgery-related binocular vision anomalies and recommends a screening protocol and risk stratification.It also discusses the expected results of binocular vision testing, the diagnostic criteria for common binocular vision problems, and strategies for treating these anomalies before and after refractive surgery.

Binocular vision problems associated with refractive surgery and the use of risk screening / 中华实验眼科杂志

Although binocular vision problems do not appear to be one of the common complications of refractive surgery,the available evidence suggests that these problems can occur after refractive surgery,and preoperative binocular vision status may predict the risk of postoperative binocular vision anomalies.Furthermore,because ophthalmologists usually do not clearly recognize binocular vision,or they do not pay enough attention to it,the existing literature may underestimate the actual prevalence of binocular vision problems after refractive surgery.This paper discusses the existing literature on refractive surgery-related binocular vision anomalies and recommends a screening protocol and risk stratification.It also discusses the expected results of binocular vision testing,the diagnostic criteria for common binocular vision problems,and strategies for treating these anomalies before and after refractive surgery.

Non-strabismic binocular vision anomalies among students of a Malaysian private university uses visual display unit / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To determine the status of non-strabismic binocular vision anomalies(NSBVA)among students of a Malaysian private university uses visual display units(VDU).<p>METHODS: A cross-sectional study was conducted among university students who use VDU 3h or more from January 2019 to May 2019. A convenient sampling method was utilized. All subjects had gone through primary eye-examinations to satisfy the inclusion criteria. Those who satisfy the inclusion criteria, further gone through the NSBVA assessment. The descriptive analysis was done to rule out the percentage of NSBVA and Chi-square test of independence was carried out to observe the association of NSBVA with age, gender and hours of VDU usage.<p>RESULTS: A total of 140 students including 88 females(62.9%)and 52 males(37.1%)participated in this study. The mean age of the participants was 22.54±1.48 years and the mean VDU usage hours were 5.76±2.49h. The percentage of NSBVA is 40% among the students those who use VDU. The occurrence of accommodative and vergence anomalies among the VDU users is 17.86% and 22.14% respectively. There was a moderate association between gender and NSBVA(<i>P</i>=0.010). However, there was no significant association observed for age(<i>P</i>=0.334)and hours of VDU usage(<i>P</i>=0.835)with NSBVA. <p>CONCLUSION: NSBVA is 40% among the students of a Malaysian private university uses VDU. Accommodation insufficiency(15%)and convergence insufficiency(10%)is more common among all NSBVA for VDU users.

Test-Retest Reliability of Functional Magnetic Resonance Imaging Activation for a Vergence Eye Movement Task / 神经科学通报·英文版

Vergence eye movements are the inward and outward rotation of the eyes responsible for binocular coordination. While studies have mapped and investigated the neural substrates of vergence, it is not well understood whether vergence eye movements evoke the blood oxygen level-dependent signal reliably in separate experimental visits. The test-retest reliability of stimulus-induced vergence eye movement tasks during a functional magnetic resonance imaging (fMRI) experiment is important for future randomized clinical trials (RCTs). In this study, we established region of interest (ROI) masks for the vergence neural circuit. Twenty-seven binocularly normal young adults participated in two functional imaging sessions measured on different days on the same 3T Siemens scanner. The fMRI experiments used a block design of sustained visual fixation and rest blocks interleaved between task blocks that stimulated eight or four vergence eye movements. The test-retest reliability of task-activation was assessed using the intraclass correlation coefficient (ICC), and that of spatial extent was assessed using the Dice coefficient. Functional activation during the vergence eye movement task of eight movements compared to rest was repeatable within the primary visual cortex (ICC = 0.8), parietal eye fields (ICC = 0.6), supplementary eye field (ICC = 0.5), frontal eye fields (ICC = 0.5), and oculomotor vermis (ICC = 0.6). The results demonstrate significant test-retest reliability in the ROIs of the vergence neural substrates for functional activation magnitude and spatial extent using the stimulus protocol of a task block stimulating eight vergence eye movements compared to sustained fixation. These ROIs can be used in future longitudinal RCTs to study patient populations with vergence dysfunctions.

Comparison of torsional amplitudes between emmetropes and myopes using after-image slides

Purpose: To describe the influence of corrected refractive error on measured torsional fusional amplitudes (TA) by comparing the TA between emmetropes and spectacle corrected myopes, using the after-image slides of the synoptophore, as targets. Methods: Fifty emmetropes (Group I) and 50 myopes (Group II) with best-corrected acuity of 6/6 in each eye were included in the study. Near point of convergence (NPC), near point of accommodation (NPA), and horizontal fusional amplitudes (HFA) were assessed in all the subjects. After-image slides, both horizontally aligned, were used as targets (without the bright flashes). One of the slides was rotated inwards, till cyclo-diplopia was reported by the subject; the procedure was repeated with the slide rotated outwards. The sum of the two readings was taken as TA. NPC, NPA, HFA, and TA were analyzed. Results: There was no significant difference in the NPC, NPA, and HFA between the two groups. The emmetropic subjects had significantly better torsional amplitude (8.4 ± 1.4 degrees) compared to myopes (7.7 ± 1.5 degrees, P = 0.03). We postulate that this difference may be due to perceived image minification, which brings the edges of retinal image of the targets closer to the fovea, thus rendering the myopes lesser tolerant to cyclodiplopia than emmetropes. Conclusion: Refractive error, corrected with spectacles, influences the measured TA. Myopic subjects have lesser torsional fusional amplitude than emmetropes.

Effects of persistent viewing of 3D TV on human visual function / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To comprehensively identify the effects of persistent viewing of 3D TV on visual function and find out the relationship between different visual functional parameters.<p>METHODS: The following four visual functional parameters: accommodation(accommodative response; accommodative microfluctuation; accommodative facility; PRA, positive relative accommodation; NRA, negative relative accommodation; gradient AC/A, the gradient accommodative convergence to accommodation ratio), vergence(DBI, distance base-in; DBO, distance base-out; NBI, near base-in; NBO, near base-out), phoria(distance and near lateral phoria), and stereopsis were measured for nineteen health participants before and after viewed 2D TV for 90min and 3D TV for 90min.<p>RESULTS: Both compared with the baseline data and the data after 2D viewing, increased near accommodative responses, decreased convergence, changed phoria(more exophoric)at distance were detected after 3D TV viewing(all <i>P</i> <0.05).<p>CONCLUSION: Prolonged viewing of 3D TV will influence human visual function, especially the disruption of the natural relationship between binocular convergence and accommodation induced by conflicting stimulus. Manufacturers and the public should consider the parameters of accommodation, vergence, and phoria as main indicators for detecting the safety of 3D TV.

Application of examinations of visual function in clinic and research / 国际眼科杂志(Guoji Yanke Zazhi)

@#Examinations of visual function have been widely performed with the increasing awareness of visual function recently. In addition to regular examinations in Ophthalmology and Optometry, examinations of visual function are also very important in clinic. Nowadays, they are considered as the basis of some diagnosis, and mainly divided into two methods: regular examinations of visual function and examinations based on psychophysics. In order to serve clinic and research better, the combination of them is highly required.

Convergence-Retraction Nystagmus: Analysis with 3-dimensional Oculography

BACKGROUND AND OBJECTIVES:Convergence-retraction oscillations are rhythmic or arrhythmic jerks of dysjunctive eye movements associated with backward displacement of the eyeballs during the convergence phase. Oscillations in convergence-retraction oscillations have been proposed to be consisted of opposed adducting saccades immediately followed by slow abducting glissades without latency. However, dynamic characteristics of convergence oscillations accompanying retraction have not been studied, and pathomechanism of these eye movements remains to be elucidated. This study was to get insights on the pathomechanisms of convergence-retraction oscillations by using 3-dimensional recording of eye movements. In particular, we intended to clarify whether the nystagmus originates from instability of vergence eye movement or of saccades. MATERIALS AND METHOD:Seven consecutive patients with convergence-retraction oscillations were recruited. All the patients received full neurological and neuro-ophthalmological evaluation by the senior author. Some of the patients underwent 3-dimensional recordings of convergence-retraction oscillations with video-oculography or magnetic search coil technique. RESULTS:Wave forms of convergence-retraction oscillations were varied. The onset of convergent eye movements was either synchronous or asynchronous between both eyes. The initial directions of eye movement was same (conjugate) or opposite (disjunctive). In some, vergence eye movements occurred only in one eye (unilateral). Convergence phase of one eye was commonly consisted of multiple steps while the other eye attained final position with a single step. The following divergent eye movements commonly overshoot the orbital midposition and were followed by correcting convergent eye movements. The velocity-amplitude relationship of convergent eye movements, which was analyzed in typical pairs of vergence oscillations, did not differ between both eyes. Divergent eye movements are slower than convergent eye movements. The both convergent and divergent eye movements were slower than the microsaccades of similar amplitudes. CONCLUSION:Quantitative analyses of convergence-retraction oscillations revealed various patterns of wave forms. The amplitude-velocity relationships of the disjunctive eye movements suggest that the slowed saccades may be due to co-contraction of the agonist and antagonist, or due to enhanced vergence eye movements by the accompanying saccades.

The Influence of Fusional Vergence on the Postoperative Ocular Alignment in Intermittent Exotropia

The purpose of this study was to evaluate the influence of fusional vergence on the ocular alignment after surgery in intermittent exotropia. We evaluated fusional convergence and divergence with rotary prism. We examined 44 patients with intermittent exotropia who were followed up postoperatively for at least 6 months from January 1995 to June 1998. The angle of deviation was measured preoperatively, 1 week after surgery and on the last follow-up day. We evaluated the break and recovery point of fusional convergence and divergence at near and far at each measurement of angle of deviation. The subjects were divided into two groups according to the deviation at the last visit : Orthophoria group and Undercorrection group. Orthophoria group was defined as having the deviation equal to or less than 15 delta of exodeviation, and undercorrection group was defined as having the deviation more than 15 delta of exodeviation. In Orthophoria group, break point and recovery point of convergence were 28.07 delta and 26.34 delta at near, 25.52 delta and 22.55 delta at far. The break point and recovery point of divergence were 18.21 delta and 12.38 delta at near, 12.70 delta and 7.73 delta at far. In Undercorrection group, break point and recovery point of convergence were 25.86 delta and 24.71 delta at near, 25.20 delta and 25.80 delta at far. The break point and recovery point of divergence were 18.86 delta and 13.29 delta at near, 17.90 delta and 15.40 delta at far. There was no significant difference between two groups. According to the change from deviation at postoperative 1 week to final deviation, the subjects were divided into four groups. We evaluated the difference of fusional convergence and divergence, according to the change of angle of deviation between postoperative 1 week and the last follow-up day, but there was no significant difference. In conclusion, we can not find any significant influence of fusional vergence on the ocular alignment after surgery in intermittent exotropia.