Efficacy of vision therapy in children with learning disability and associated binocular vision anomalies

Clinical features of Sudanese patients presenting with binocular vision anomalies: A hospital-based study

Binocular vision anomalies are major causes of asthenopia symptoms, particularly among the younger population. This study aimed to report the clinical characteristics of Sudanese patients with binocular disorders who attended the orthoptic clinic at Al-Neelain Eye Hospital. In this retrospective hospital-based study, we analyzed data from 304 patients with binocular vision anomalies who visited the orthoptic clinic between October 2020 and June 2021. We collected information on demographics, symptoms, and eye tests such as visual acuity (VA), refractive error (RE), angle of deviation, and the assessment of fusional vergence. Our findings indicated that exophoria was the most common binocular vision anomaly, affecting 79.8% of males and 71.6% of females (p=0.731). Children between 6 and 17 years old showed the highest prevalence of exophoria (75.9%) (p=0.0001). Among patients with exophoria, 100% reported itching associated with tearing during fixation, while 89.5% experienced difficulty in fixation. Refractive error varied by the type of binocular vision disorders (p=0.0001), with higher hyperopia observed in cases of unilateral esotropia and alternate esotropia (+3.571±1.238 D and +3.023±1.553 D, respectively). Positive fusional vergence (PFV) differed by types of binocular vision disorders (p=0.0001) with high PFV in esophoria (18.063±6.848∆) compared to low PFV in exophoria (12.80±5.313∆). The most common types of exophoria were convergence weakness exophoria (45.39%), followed by convergence insufficiency (20.39%). The study concluded that exophoria was the most common binocular vision anomaly among Sudanese patients, with convergence weakness and convergence insufficiency being the predominant anomalies. Headache was commonly prevalent among patients with binocular vision problems. Higher hyperopia was found in esodeviation, while low PFV was associated with exodeviation.

Translation and validation of convergence insufficiency symptom survey to Italian: Psychometric results

PURPOSE

This study aimed to translate the Convergence Insufficiency Symptom Survey (CISS) into the Italian language and assess psychometric properties of the translated questionnaire (CISS_I).

METHODS

The CISS_I was arranged according to guidelines for a comprehensive multistep methodologic process for translating, adapting, and validating psychometric instruments in health care research. The CISS_I questionnaire was administered to 103 volunteers (21.8 ± 2.2 years), students in higher education, at two different times. A complete optometric evaluation was performed including subjective refraction, best corrected visual acuity, near point of convergence, prism fusional ranges to blur, diplopia and recovery, TNO stereo test and prism cover test for measurement of heterophoria.

RESULTS

The performance of the CISS_I in terms of validity showed some points of weakness. Sensitivity was 42%, specificity was 74%, positive predictive value was 27% and negative predictive value was 85%. The area under the ROC curve was 0.672. On the contrary, the results showed good internal consistency of the CISS_I (Cronbach's alpha - α=0.89) and good test-retest reliability (ICC = 0.92). Rasch analysis showed good model fit (all items, except one, with infit and outfit mean square between 0.7 and 1.3), good measurement precision (person separation = 2.66) and good targeting -0,81 logits but also some evidence of multidimensionality.

CONCLUSIONS

The CISS_I showed some point of weakness in terms of validity but also good psychometric properties and has been shown to be applicable to an Italian speaking population to quantify the visual discomfort associated with near vision in higher education students. The results show that high CISS_I score is not necessarily linked to convergence insufficiency, while low scores can exclude the presence of this anomaly. The CISS_I can help in interpreting and monitoring convergence insufficiency symptoms in already identified subjects, but it is not suitable for screening a general population of young adults.

Measures of accommodative function in secondary school year 9 and year 13: a 4-year longitudinal study

Purpose

To characterize accommodative function in secondary school children in year 9 and year 13 and assess the possible relationship between daily working conditions (number of near work hours and distances) and accommodation variables related to accommodative excess.

Methods

This was a prospective study. Participants were 43 subjects who were first examined in year 9 and then again when they were in year 13. The accommodation variables measured in each session were as follows: accommodation amplitude (AA), accommodative response (AR), monocular and binocular accommodation flexibility (MAF and BAF), negative relative accommodation (NRA), and positive relative accommodation (PRA). Other data recorded were the number of hours spent working at near vision tasks and the distances used for these tasks. Participants were classified as those with accommodation variables within the normal range (NA) and those with variables suggesting accommodative excess (AE).

Results

Several accommodative function variables were below normative values in both year 9 and year 13. The number of subjects classified as having AE went from 27.9% in year 9 to 58.1% in year 13 according to AR (p < 0.005) and from 23.3 to 46.5% according to MAF (p = 0.024). More near work was reported in year 13 (44.6 h/week) than year 9 (32.7 h/week) (p < 0.001). It emerged that subjects in year 13 spent more hours working at near if they had AE than if they were assigned to the NA group. No differences were detected in near work distances used by subjects in the NA and AE groups in both years.

Conclusions

In both school years, values outside the norm were detected in several accommodative function measures. Also, devoting more hours to near work was linked to a greater extent of accommodative excess. We would therefore recommend regular accommodative function assessment in secondary school children.

The Changes in Visual Acuity Values of Japanese School Children during the COVID-19 Pandemic

The coronavirus disease 2019 (COVID-19) pandemic may result in a greater decrease in visual acuity (VA) among Japanese children. Our study aimed to examine Japanese children’s VA during the pandemic. VA data were collected using standard eye tests during school health check-ups conducted in 2019 and 2020 on 5893 children, in seven public elementary schools and four public junior high schools in Tokyo, Saitama, Kanagawa, and Shizuoka. VA changes were statistically analyzed. The relationship between the survey year and poor VA yielded a significant regression coefficient for the surveyed years in elementary and junior high school students. The 2019 VA value and VA change from 2019 to 2020 demonstrated a significant regression coefficient in elementary school students with VAs of “B (0.7−0.9)” and “C (0.3−0.6)”, and junior high school students with VAs of “B”, “C”, and “D (<0.3)”. An analysis of the relationship between the survey year and eye laterality of VA yielded a significant regression coefficient in the surveyed years for elementary (OR, 1.516; 95% CI, 1.265−1.818) and junior high school students (OR, 1.423; 95% CI, 1.136−1.782). Lifestyle changes during the COVID-19 pandemic might have affected VA and eye laterality in Japanese children.

Distribution of Visual and Oculomotor Alterations in a Clinical Population of Children with and without Neurodevelopmental Disorders

A prospective, non-randomized comparative study was conducted to compare the distribution of oculomotor and visual alterations in children with neurodevelopmental disorders and healthy children without such disorders. Sixty-nine children (aged 6-13 years) were enrolled and divided into three groups: a control group (CG) of 23 healthy children; a group of 18 healthy children with oculomotor abnormalities (OAG); and a group of 28 children with a neurodevelopmental disorder (NDDG), with 15 cases of dyslexia, 7 cases of developmental coordination disorder (DCD) and 6 cases of attention deficit/hyperactivity disorder (ADHD). Significantly worse near stereopsis was found in NDDG compared with CG (p < 0.001) and OAG (p = 0.001). Likewise, a significantly lower amplitude of accommodation was found in NDDG compared with CG in both the right (p = 0.001) and left eyes (p < 0.001). No statistically significant differences between groups were found in the measurement of near and distance phoria (p ≥ 0.557), near point of convergence (p = 0.700) and fusional vergences (p ≥ 0.059). Significantly impaired oculomotor test scores were found in NDDG compared with CG (p < 0.001), with no significant differences between OAG and NDDG (p ≥ 0.063). The comparison between the three types of neurodevelopmental disorders included revealed the presence of a significantly lower amplitude of accommodation in children with DCD compared with dyslexics. Furthermore, less exophoria at near was present in children with dyslexia compared with children with ADHD (p = 0.018) and DCD (p = 0.054). In conclusion, children with dyslexia, ADHD and DCD show an altered oculomotor pattern and a more reduced amplitude of accommodation, not always compatible with the diagnostic criteria of an accommodative insufficiency. Accommodative and binocular vision problems are not always present in these children and cannot be considered an etiologic factor.

Headache and musculoskeletal pain in school children are associated with uncorrected vision problems and need for glasses: a case-control study

Musculoskeletal pain and headache are leading causes of years lived with disability, and an escalating problem in school children. Children spend increasingly more time reading and using digital screens, and increased near tasks intensify the workload on the precise coordination of the visual and head-stabilizing systems. Even minor vision problems can provoke headache and neck- and shoulder (pericranial) pain. This study investigated the association between headaches, pericranial tenderness, vision problems, and the need for glasses in children. An eye and physical examination was performed in twenty 10–15 year old children presenting to the school health nurse with headache and pericranial pain (pain group), and twenty age-and-gender matched classmates (control group). The results showed that twice as many children in the pain group had uncorrected vision and needed glasses. Most children were hyperopic, and glasses were recommended mainly for near work. Headache and pericranial tenderness were significantly correlated to reduced binocular vision, reduced distance vision, and the need for new glasses. That uncorrected vision problems are related to upper body musculoskeletal symptoms and headache, indicate that all children with these symptoms should have a full eye examination to promote health and academic performance.

Interventions for convergence insufficiency: a network meta-analysis

BACKGROUND

Convergence insufficiency is a common binocular vision disorder in which the eyes have a strong tendency to drift outward (exophoria) with difficulty turning the eyes inward when reading or doing close work.

OBJECTIVES

To assess the comparative effectiveness and relative ranking of non-surgical interventions for convergence insufficiency through a systematic review and network meta-analysis (NMA).

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, PubMed and three trials registers up to 20 September 2019.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) examining any form of non-surgical intervention versus placebo, no treatment, sham treatment, or other non-surgical interventions. Participants were children and adults with symptomatic convergence insufficiency.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology. We performed NMAs separately for children and adults.

MAIN RESULTS

We included 12 trials (six in children and six in adults) with a total of 1289 participants. Trials evaluated seven interventions: 1) office-based vergence/accommodative therapy with home reinforcement; 2) home-based pencil/target push-ups; 3) home-based computer vergence/accommodative therapy; 4) office-based vergence/accommodative therapy alone; 5) placebo vergence/accommodative therapy or other placebo intervention; 6) prism reading glasses; and 7) placebo reading glasses. Six RCTs in the pediatric population randomized 968 participants. Of these, the Convergence Insufficiency Treatment Trial (CITT) Investigator Group completed four RCTs with 737 participants. All four CITT RCTs were rated at low risk of bias. Diagnostic criteria and outcome measures were identical or similar among these trials. The four CITT RCTs contributed data to the pediatric NMA, incorporating interventions 1, 2, 3 and 5. When treatment success was defined by a composite outcome requiring both clinical measures of convergence to be normal, and also show a pre-specified magnitude of improvement, we found high-certainty evidence that office-based vergence/accommodative therapy with home reinforcement increases the chance of a successful outcome, compared with home-based computer vergence/accommodative therapy (risk ratio (RR) 1.96, 95% confidence interval (CI) 1.32 to 2.94), home-based pencil/target push-ups (RR 2.86, 95% CI 1.82 to 4.35); and placebo (RR 3.04, 95% CI 2.32 to 3.98). However, there may be no evidence of any treatment difference between home-based computer vergence/accommodative therapy and home-based pencil/target push-ups (RR 1.44, 95% CI 0.93 to 2.24; low-certainty evidence), or between either of the two home-based therapies and placebo therapy, for the outcome of treatment success. When treatment success was defined as the composite convergence and symptom success outcome, we found moderate-certainty evidence that participants who received office-based vergence/accommodative therapy with home reinforcement were 5.12 (95% CI 2.01 to 13.07) times more likely to achieve treatment success than those who received placebo therapy. We found low-certainty evidence that participants who received office-based vergence/accommodative therapy with home reinforcement might be 4.41 (95% CI 1.26 to 15.38) times more likely to achieve treatment success than those who received home-based pencil push-ups, and 4.65 (95% CI 1.23 to 17.54) times more likely than those who received home-based computer vergence/accommodative therapy. There was no evidence of any treatment difference between home-based pencil push-ups and home-based computer vergence/accommodative therapy, or between either of the two home-based therapies and placebo therapy. One RCT evaluated the effectiveness of base-in prism reading glasses in children. When base-in prism reading glasses were compared with placebo reading glasses, investigators found no evidence of a difference in the three outcome measures of near point convergence (NPC), positive fusional vergence (PFV), or symptom scores measured by the Convergence Insufficiency Symptom Survey (CISS). Six RCTs in the adult population randomized 321 participants. We rated only one RCT at low risk of bias. Because not all studies of adults included composite success data, we could not conduct NMAs for treatment success. We thus were limited to comparing the mean difference (MD) between interventions for improving NPC, PFV, and CISS scores individually using data from three RCTs (107 participants; interventions 1, 2, 4 and 5). Compared with placebo treatment, office-based vergence accommodative therapy was relatively more effective in improving PFV (MD 16.73, 95% CI 6.96 to 26.60), but there was no evidence of a difference for NPC or the CISS score. There was no evidence of difference for any other comparisons for any outcomes. One trial evaluated base-in prism glasses prescribed for near-work activities and found that the prism glasses group had fewer symptoms compared with the placebo glasses group at three months (MD -8.9, 95% CI -11.6 to -6.3). The trial found no evidence of a difference with this intervention in NPC or PFV. No adverse effects related to study treatments were reported for any of the included studies. Excellent adherence was reported for office-based vergence/accommodative therapy (96.6% or higher) in two trials. Reported adherence with home-based therapy was less consistent, with one study reporting decreasing adherence over time (weeks 7 to 12) and lower completion rates with home-based pencil/target push-ups.

AUTHORS' CONCLUSIONS

Current research suggests that office-based vergence/accommodative therapy with home reinforcement is more effective than home-based pencil/target push-ups or home-based computer vergence/accommodative therapy for children. In adults, evidence of the effectiveness of various non-surgical interventions is less clear.

Evaluation of a Novel Quality of Life Scale for Schoolchildren with Nonstrabismic Binocular Vision Anomalies

BACKGROUND

The professional Quality of Life Scale (QLS) can provide a valuable reference for the diagnosis of visual function anomalies. In the present study, we aimed to design a novel QLS to specially quantify the life quality of schoolchildren with nonstrabismic binocular vision anomalies (NSBVAs) in China.

METHODS

The novel QLS, named QOL-CVF20, was established based on classical vision-related scales and the administration of the questionnaire to 116 schoolchildren with NSBVAs and 100 healthy schoolchildren in China. The diagnostic reference value between QOL-CVF20 and VF-14 was evaluated on the questionnaires to 240 schoolchildren with NSBVAs and 238 healthy schoolchildren.

RESULTS

All the subjects could complete the QOL-CVF20 questionnaires independently. QOL-CVF20 had good structural validity, content validity, and discriminant validity, when it was applied in Chinese schoolchildren. The average score of the NSBVA group was significantly lower than that of the control group (49.0 ± 6.9 vs. 69.7 ± 6.7, respectively; P < 0.01). Moreover, the average score of cured NSBVA schoolchildren after treatment (61.8 ± 22.6) was significantly improved (P < 0.01). Receiver operating characteristic curve analysis showed that QOL-CVF20 reflected strong separation between the NSBVA and healthy groups (AUC = 0.901). Meanwhile, QOL-CVF20 could detect individuals with NSBVAs with specificity of 0.847 and sensitivity of 0.846. The critical value of 58.50 in QOL-CVF20 could be effectively applied for quality of life assessment in schoolchildren with NSBVAs.

CONCLUSIONS

QOL-CVF20 could quantify the life quality of schoolchildren with NSBVAs and might be served as a valuable reference for early diagnosis and clinical evaluation of NSBVAs.

Bibliometric study of scientific research on optometric visual therapy

PURPOSE

To analyze scientific research in the field of visual therapy through a bibliometric study.

METHODS

The database used in this bibliometric study was SCOPUS, the largest abstract and citation database of peer-reviewed literature, covering scientific journals, books, and conference proceedings. Using remote downloading techniques, articles published between 1946 and 2017 were selected by entering the main descriptors: "optometric vis* training", "optometric vis* therapy", "vis* therapy", "vis* training" limited to the title, key words and/or abstract. We applied the following bibliometric indicators: Price's index, doubling time and annual growth rate, Price's transience index, Lotka's Law, h factor, and Bradford's zones.

RESULTS

The authors retrieved 294 original articles from the temporal interval 1946-2017 (articles, reviews, letters to the director, etc.), discarding 15 of them for not meeting the study requirements. Annual growth rate was 39.62%, the timeframe 1987-1983 containing the most number of documents. United States was the country with the highest production, with more than 60% of the records. The most productive institutions are State University of New York System, SUNY State College of Optometry, and Southern California College of Optometry. Classification of authors based on productivity is strongly concentrated in small producers, with a transient index of 80.53. The total number of authors was 488, representing a co-authorship index of 1.75.

CONCLUSION

Bibliometric studies have become essential tools for assessing scientific publications.

Access to primary and community health-care services for people 16 years and over with intellectual disabilities: a mapping and targeted systematic review

Background

In 2015, approximately 2.16% of adults were recorded as having intellectual disabilities. UK government policy is that adults with intellectual disabilities should access mainstream health services. However, people with intellectual disabilities experience challenges when accessing primary and community health services that can lead to inequalities and shorter life expectancy.

Objectives

To map and review the evidence on access to primary and community health-care services for adults with intellectual disabilities and their carers. To identify influencing factors for gaining access to primary and community health-care services. To determine which actions, interventions or models of service provision improve entry access to these services for people with intellectual disabilities and their carers. Finally, to identify the gaps in evidence and provide implications for health care and recommendations for research.

Data sources

MEDLINE, The Cochrane Library, Web of Science, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Applied Social Sciences Index and Abstracts (ASSIA) and Education Resources Information Center (ERIC) were searched from 2002 to 2018.

Review methods

The mapping review methodology included an extensive literature search, article selection and data extraction of relevant abstracts. Findings from the mapping review informed the scope of the targeted systematic review. Methodology for the targeted systematic review included an extensive literature search informed by the mapping review, article selection, data extraction, quality appraisal and narrative synthesis.

Results

The mapping review included 413 studies with data extraction completed on abstracts. The targeted systematic review synthesised the evidence from 80 studies reported in 82 publications. During the review process, the team identified three key points at which people with intellectual disabilities potentially interacted with primary and community health-care services: identifying needs, accessing services and interaction during a consultation. In addition, there were a number of papers about interventions or innovations to improve access. Evidence from the studies was synthesised within the four clusters. Influencing factors were identified: staff knowledge/skills, joint working with learning disability services, service delivery model, uptake, appointment making, carer/support role, relationship with staff, time, accessible information and communication. The influencing factors were cross-cutting through the literature, with certain factors having more importance in certain clusters.

Limitations

The main limitation was the weak evidence base. The studies generally had small samples, had study designs that were open to potential biases and measured only short-term outcomes.

Conclusions

Health checks were found to help identify health needs and improve the care of long-term conditions. Important factors for accessing health services for adults with intellectual disabilities were consistency of care and support, staff training, communication skills and time to communicate, and provision of accessible information. Health professionals need to ensure that there is joint working between different services, clear communication and accurate record-keeping. Future research questions centre on the need to develop and value creative study designs capable of addressing the complex issues identified in the findings of the review for this complex population.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 5. See the NIHR Journals Library website for further project information.

Near Points of Convergence and Accommodation in a Population of University Students in Iran

Purpose

To determine the distribution of the near point of convergence (NPC) and near point of accommodation (NPA) in a young student population in Iran.

Methods

The subjects were selected using a cluster sampling method. All students underwent optometry tests, including visual acuity measurement, refraction, and cover test, as well as ophthalmic examinations. The NPC and NPA were measured using an accommodative target (near Snellen chart).

Results

Of 1,595 students, the data of 1,357 were analyzed. The mean NPC and NPA in the total sample were 7.25 cm (95% confidence interval [CI], 7.02 to 7.48) and 9.99 cm (95% CI, 9.69 to 10.29), respectively. Older age was associated with an increase in the NPC, which increased from 6.98 cm in 18-20 years olds to 9.51 cm in those over 30 years. The NPA was significantly associated with age and refractive errors in the multiple linear regression model, increasing from 9.92 cm in 18-20 years olds to 11.44 cm in those over 30 years ( P = 0.003). Hyperopic eyes had lower NPA than myopic and emmetropic eyes ( P = 0.001). In younger age groups, the mean accommodation amplitude was lower than the mean Hofstetter value. Moreover, with age, especially after 30 years, the mean values surpassed those determined using the Hofstetter formula.

Conclusion

The NPC values in this study were lower than those previously reported for identical age groups. The Hofstetter formula is not always an accurate predictor of the accommodation amplitude in the Iranian adult population.

Frequency of Visual Deficits in Children With Developmental Dyslexia

Importance

Developmental dyslexia (DD) is a specific learning disability of neurobiological origin whose core cognitive deficit is widely believed to involve language (phonological) processing. Although reading is also a visual task, the potential role of vision in DD has been controversial, and little is known about the integrity of visual function in individuals with DD.

Objective

To assess the frequency of visual deficits (specifically vergence, accommodation, and ocular motor tracking) in children with DD compared with a control group of typically developing readers.

Design, Setting, and Participants

A prospective, uncontrolled observational study was conducted from May 28 to October 17, 2016, in an outpatient ophthalmology ambulatory clinic among 29 children with DD and 33 typically developing (TD) children.

Main Outcomes and Measures

Primary outcomes were frequencies of deficits in vergence (amplitude, fusional ranges, and facility), accommodation (amplitude, facility, and accuracy), and ocular motor tracking (Developmental Eye Movement test and Visagraph eye tracker).

Results

Among the children with DD (10 girls and 19 boys; mean [SD] age, 10.3 [1.2] years) and the TD group (21 girls and 12 boys; mean [SD] age, 9.4 [1.4] years), accommodation deficits were more frequent in the DD group than the TD group (16 [55%] vs 3 [9%]; difference = 46%; 95% CI, 25%-67%; P < .001). For ocular motor tracking, 18 children in the DD group (62%) had scores in the impaired range (in the Developmental Eye Movement test, Visagraph, or both) vs 5 children in the TD group (15%) (difference, 47%; 95% CI, 25%-69%; P < .001). Vergence deficits occurred in 10 children in the DD group (34%) and 5 children in the TD group (15%) (difference, 19%; 95% CI, -2.2% to 41%; P = .08). In all, 23 children in the DD group (79%) and 11 children in the TD group (33%) had deficits in 1 or more domain of visual function (difference, 46%; 95% CI, 23%-69%; P < .001).

Conclusions and Relevance

These findings suggest that deficits in visual function are far more prevalent in school-aged children with DD than in TD readers, but the possible cause and clinical relevance of these deficits are uncertain. Further study is needed to determine the extent to which treating these deficits can improve visual symptoms and/or reading parameters.

Vision status of children aged 7-15 years referred from school vision screening in Norway during 2003-2013: a retrospective study

BACKGROUND

Undetected vision problems is an important cause of reduced academic achievement, performance in everyday life and self-esteem. This receives little attention in national health care services in Norway even though most of these vision problems are easily correctable. There are no published data on how many Norwegian schoolchildren are affected by correctable vision problems. This study aims to determine the vision status in primary and secondary schoolchildren referred from vision screening during the 10 year period of 2003-2013.

METHODS

Of the 1126 children (15%) aged 7-15 years referred to the university eye clinic by the school screening program, all 782 who attended the eye clinic were included in the study. Patient records were retrospectively reviewed with regard to symptoms, refractive error, best corrected visual acuity (BCVA) of logMAR, binocular vision, ocular health and management outcomes.

RESULTS

Previously undetected vision problems were confirmed in 650 (83%) of the children. The most frequent outcomes were glasses (346) or follow-up (209), but types of treatment modalities varied with age. Mean refractive errors were hyperopic for all age groups but reduced with age (ANOVA, p < 0.001). Overall, 51% were hyperopic, 32% emmetropic and 17% myopic. Refractive errors did not change across the decade (linear regression, all p > 0.05). Mean logMAR BCVAs were better than 0.0 and improved with age (ANOVA, p < 0.001). The most prevalent symptoms were headaches (171), near vision problems (149) and reduced distance vision (107).

CONCLUSIONS

The vision screening identified children with previously undetected visual problems. This study shows that the types of visual problems varied with age and that most problems could be solved with glasses. Our results stress the importance of regular eye examinations and that vision examinations should be included in primary health care services. Furthermore, there is a need for raised awareness among parents and teaching staff regarding vision problems in children.

Nonstrabismic binocular dysfunctions and cervical complaints: The possibility of a cross-dysfunction

The aim of this study is to establish a relationship between non-strabismic binocular dysfunction and neck pain. One hundred twelve participants underwent binocular vision assessment by evaluating horizontal heterophoria, horizontal and vertical fusional vergence ranges and vergence facility. The subjects were classified into two groups: binocular anomalies and normal binocular function. Neck complaints were measured with the Neck Disability Index, visual analogue scale, cervical range of motion, deep-flexor muscle activation score (AS) and performance index (PI). Our results showed that participants with low AS had significantly altered values of lateral phoria (near) (mean = -6.99 SD ± 6.96 PD) and PFV (near) blur (mean = 9.49 SD ± 5.45 PD) against those who presented normal AS (lateral phoria (near) mean = -3.64 SD ± 6.37 PD; PFV (near) blur mean = 12.84 SD ± 6.20 PD). In addition, participants with NFV (near) recovery outside the norm had a significantly lower right side-bending (mean = 35.63 SD ± 8.35 PD) than those within the standard (mean = 39.64 SD ± 9 PD). The subjects with binocular vision impairment showed a diminished response to the deep cervical musculature, with low AS and PI, as well as a tendency to suffer from cervicalgia of more than three months’ evolution and a lower range of motion.