Query: Convergence Insufficiency

title: Receiver operating characteristic curve analysis of clinical signs for screening of convergence insufficiency in young adults
abstract: Convergence insufficiency (CI) is a dysfunction of binocular vision that is associated with various signs and symptoms in near work. However, CI screening is performed less frequently in adults than in children. We aimed to evaluate the ability of screening tests to discriminate CI from other binocular vision anomalies and normal binocular vision in young adults. One hundred eighty four university students (age, 18 28 years) who underwent an eye examination due to ocular discomfort were included. Near point of convergence (NPC) phoria, accommodative amplitude, fusional vergence, the ratio of accommodative convergence to accommodation, relative accommodation, binocular accommodative facility, vergence facility, and the values corresponding to Sheard's and Percival's criteria were evaluated. Receiver operating characteristic (ROC) curve analysis for each test was also performed. The prevalence of CI ranged from 10.3% to 21.2% depending on the signs and the presence of CI associated with accommodative disorders. Assessments based on NPC, Sheard's criterion, and Percival's criterion showed high discriminative ability, with the ability being higher between the CI and normal binocular vision groups than between the CI and non CI groups. Sheard's criterion showed the highest diagnostic performance in discriminating CI with three signs from the non CI group. The cut off values were 7.2 cm for NPC, 0.23 to 1.00 for Sheard's criterion, and 4.00 to 2.33 for Percival's criterion. Our results suggest that the use of Sheard's criterion with NPC shows high performance for screening of CI.

title: Treatment and compliance with virtual reality and anaglyph based training programs for convergence insufficiency
abstract: Convergence insufficiency may be treated by visual exercises designed to increase convergence while maintaining single, clear, binocular vision. However, compliance with treatment is problematic, as patients often cease treatment when symptoms start to improve and before treatment is complete. The purpose of the present study was to assess the feasibility of using gamification of vision training to: (a) treat convergence insufficiency; and (b) improve compliance to treatment in comparison to a conventional treatment over a six week treatment period.

title: Factor structure of the convergence insufficiency symptom survey questionnaire
abstract: The purpose of this study is to analyze the factorial structure of the Convergence Insufficiency Symptom Survey questionnaire with 15 items, in order to identify latent dimensions that can contribute to a more focused implementation. The questionnaire was self administered in paper by 183 university students, in the age span of 18 to 30. Both Kaiser Meyer Olkin measure and Bartlett's sphericity test were performed to ensure the validity of the factorization. In order to analyze the principal components, factors which obtained eigenvalues greater than 1 were chosen. The extraction of factors was performed after computing a Promax rotation and a Kaiser criterion. In each extracted factor, the internal consistency was used to prove its reliability. Bartlett's sphericity test was statistically significant (p <0.001) and the Both Kaiser Meyer Olkin test was 0.89, confirming the factorization of this instrument. Exploratory factor analysis followed by a Promax rotation and scree plots graphic, extracted three factors that explained 62.1% of the total variance. The composition of each factor suggests the following meanings: Factor 1 (somatic sensation) includes 8 of 15 items; Factor 2 (impaired vision) includes 3 of 15 items; Factor 3 (cognitive performance) includes 4 of 15 items. Cronbach's alpha coefficient demonstrated good internal consistency (a> 0.75) in three dimensions. The multivariate statistical analysis of the Convergence Insufficiency Symptom Survey revealed a three factor structure, so new forms of questionnaire analysis can be designed in order to obtain gains in the management of a symptomatic patient, using 3 subscores, one for each factor, instead of a total score. The factorial structure of the questionnaire can be used with a high level of confidence in future investigations, which aim to assess which dimensions are most affected in each type of visual changes and develop more targeted therapeutic performances.

title: Central Mini plication of the Medial Rectus for Convergence Insufficiency
abstract: Five cases with a mean SD) age of 61 (12.02) years are described to study the outcomes of treatment with central mini plication of the medial rectus (MR) muscles in adult convergence insufficiency with diplopia and near exotropia: mean preoperative deviation: 18 2) pd. Surgical outcome was considered to be favorable when diplopia and symptoms were resolved and final exotropia at near was =8 pd at the end of follow up. A central mini plication of the medial rectus (MR) muscles was performed in 5 patients (4 unilateral) Overcorrection at distance vision was recorded in 3 cases; this resolved by 3 months postoperatively. There was not overcorrection at near vision in any case. None of the cases operated on had overcorrection at the end of follow up. The final horizontal deviation was =8 pd at near vision, except for 1 case. Symptoms and diplopia resolved in every case but 2/5 required reoperations. The mean follow up was 8 (2.12) months. Central mini plication of 1 or 2 medial rectus muscles can improve the symptoms and signs of exotropia associated with convergence insufficiency when exercises and the prisms are rejected by the patients and when these approaches have not solved the problem.

title: Psychometric Assessment of the Persian Version of the Revised Convergence Insufficiency Symptom Survey in Young Adults with Convergence Insufficiency
abstract: To translate the Convergence Insufficiency Symptom Survey (CISS) to Persian and to assess its validity and reliability in a group of young adult Iranian patients with convergence insufficiency (CI)  The questionnaire was translated in backward and forward phases. Face validity was measured using a 6 point scale (very weak, weak, moderate, good, very good, best) and a score of =4 for each item indicated an acceptable face validity. The content validity was assessed using three indices of relevancy, clarity, and comprehensiveness. Relevancy and clarity were checked for each item and for the whole scale using a 4 point scale (1 undesirable, 2 relatively desirable, 3 desirable, 4 completely desirable) and Item Content Validity Index (I CVI) and Scale Content Validity Index (S CVI) were calculated for the above indices. Comprehensiveness was measured at the scale level using a 4 point scale (1 incomprehensive, 2 relatively comprehensive, 3 comprehensive, 4 totally comprehensive) and S CVI was calculated. The internal consistency and test retest reliability were assessed using Cronbach's alpha coefficient and interclass correlation coefficient (ICC) respectively. To evaluate discriminant validity, CI was categorized into mild, moderate, and severe stages, and the mean overall CISS score was compared between these groups.  Thirty CI patients aged 18 34 years participated in this study. On face validity assessment, all items finally had a score of =4. As for relevancy and clarity, I CVI was above 80% for all items, and S CVI was 98.8% and 96.6% respectively. The S CVI was 100% for comprehensiveness. The overall Cronbach's coefficient and ICC were 0.77 and 0.95, respectively. There was a significant difference in the overall score between the three severity groups.  The Persian CISS is a valid and reliable tool for clinical and research applications.

title: Convergence Insufficiency Neuro mechanism in Adult Population Study Randomized Clinical Trial: Clinical Outcome Results
abstract: These data confirm the effectiveness of office based vergence/accommodative therapy for improving the near point of convergence and positive fusional vergence in young adults with symptomatic convergence insufficiency within a double masked longitudinal randomized clinical trial.  This study aimed to report changes in clinical signs and symptoms of convergence insufficiency from a randomized clinical trial evaluating the effectiveness of office based vergence/accommodative therapy for young adults with symptomatic convergence insufficiency.  In this double masked, randomized clinical trial, convergence insufficiency patients (n 50; average age, 21 3 years; range, 18 to 32 years) were randomized to either office based vergence/accommodative therapy or office based placebo therapy. Improvements in (1) near point of convergence, (2) positive fusional vergence, and (3) self reported symptoms (Convergence Insufficiency Symptom Survey [CISS] score) were evaluated after twelve 1 hour sessions of treatment within the office comparing the results from the vergence/accommodative therapy and the placebo therapy groups.  The mean near point of convergence improved by 6.0 and 3.1 cm in the vergence/accommodative and placebo therapy groups, respectively (mean difference of 2.9 cm; 95% confidence interval [CI] 4.6 to 1.0 cm; P .01) The mean positive fusional vergence increased by 17.3 and 7.4D in the vergence/accommodative and placebo therapy groups, respectively (mean difference of 9.9D; 95% CI, 4.9 to 16.0D; P .001) The mean CISS score improved by 12.4 and 10.1 points in the vergence/accommodative and placebo therapy groups, respectively (mean difference of 2.3 points; 95% CI, 8.3 to +4.6 points; P .56) CONCLUSIONS Our results demonstrate that office based vergence/accommodative therapy is effective for improving the near point of convergence and positive fusional vergence in young adults with symptomatic convergence insufficiency. However, given that both treatment groups had a similar reduction in self reported symptoms, we recommend that the CISS be revised if it is to be used as an outcome measure in future studies of convergence insufficiency.

title: Changing vergence function in persons with Parkinson's disease and convergence insufficiency.
abstract: Individuals with Parkinson's disease and convergence insufficiency were assigned vergence training. After two months, average positive fusional vergence increased and average near point of convergence decreased. Vergence can be improved with training in persons with Parkinson's disease who also have convergence insufficiency.

title: Effectiveness of vergence/accommodative therapy for accommodative dysfunction in children with convergence insufficiency
abstract: To determine the effectiveness of office based vergence/accommodative therapy for improving accommodative amplitude and accommodative facility in children with symptomatic convergence insufficiency and accommodative dysfunction.

title: Reflexive Fusional Vergence and Its Plasticity Are Impaired in Convergence Insufficiency
abstract: We compared the adaptive capacities of reflexive fusional convergence and divergence in 10 participants with untreated convergence insufficiency (CI) to 10 age matched binocularly normal controls (BNCs) in an effort to elucidate the functional basis of CI.  Vergence responses were monitored binocularly at 250 Hz using video based infrared oculography, while single and double step disparity stimuli were viewed dichoptically. The double step stimuli were designed to induce an adaptive increase in the convergence or divergence reflexive fusional response dynamics.  As expected, convergence responses in the CI population were significantly slower at baseline (BNC 12.0 1.8deg/s vs. CI 7.4 2.5deg/s; P 0.001) but divergence response velocities were similar between groups (P 0.38) Critically, we observed an impaired adaptive change in convergence peak velocities in the CI group when compared to BNCs 18.2% 27.3% vs. 25.4% 9.8% P 0.001) Adaptive changes in reflexive fusional divergence responses were similar between groups (P 0.5) and significantly less robust when compared to BNC convergence.  The results support the hypothesis that the adaptive capacities of vergence are related to the strength of the underlying reflexive fusional response. Combined, the evidence suggests that the clinical condition of convergence insufficiency is underpinned by an underdeveloped or perturbated reflexive fusional vergence response mechanism. We relate these observations to different clinical guidelines for the management and treatment of this condition.

title: Association between convergence insufficiency and temporomandibular disorder cross sectional study
abstract: Evaluate whether there is an association between convergence insufficiency and temporomandibular disorder (TMD) and whether there is an association between pain and range of motion in different degrees of TMD.  We evaluated 138 individuals with TMD and 46 without TMD using the Research Diagnostic Criteria for temporomandibular disorders, the Fonseca Anamnestic Index (FAI) Numeric Pain Rating Scale, and the measurement of mandibular range of motion (ROM) Convergence insufficiency was diagnosed using the convergence test and Convergence Insufficiency Symptom Survey. Analysis of variance was used to compare age and mandibular ROM. The Kruskal Wallis was used to compare mandibular ROM and pain between groups. The chi square test was used to evaluate associations between TMD subgroups and the FAI, sex, and ocular convergence.  The majority of individuals without TMD did not exhibit convergence insufficiency. The frequency convergence insufficiency was significantly higher among individuals with severe TMD p 0.003) Mean pain severity differed between individuals with and without TMD. Mandibular ROM diminished with the increase in TMD severity.  Convergence insufficiency, age, the increase in pain, and the reduction in mandibular range of motion were associated with the degrees of TMD severity. Despite the significant associations between convergence insufficiency and both pain and TMD severity, these variables cannot be indicated as predictive factors due to the low variability in the linear regression analysis  The present findings can assist in decision making regarding the treatment of severe TMD and the evaluation of ocular convergence.