Prevalence of general binocular dysfunctions among rural schoolchildren in South Korea

BACKGROUND/PURPOSE

To assess the prevalence of nonstrabismic accommodative and vergence dysfunctions among primary schoolchildren in Hampyeong, a rural area of South Korea.

METHODS

Five hundred and eighty-nine primary schoolchildren, 8-13 years old, were each given a thorough eye examination, including binocular-vision testing, near point of convergence, horizontal phoria measurement by von Graefe, and negative and positive vergence amplitudes with prism bar, to determine any form of accommodative or vergence dysfunctions.

RESULTS

Of the 589 participants examined, 168 (28.5%) primary schoolchildren presented some form of nonstrabismic accommodative or vergence dysfunctions. The prevalence of accommodative dysfunctions and vergence dysfunctions was 13.2% and 9%, respectively. Convergence insufficiency (10.3%) was more prevalent than convergence excess (1.9%), and accommodative insufficiency (5.3%) was more prevalent than accommodative excess (1.2%).

CONCLUSION

This study suggests that nonstrabismic accommodative and vergence dysfunctions are prevalent in the rural area of South Korean primary schoolchildren, and convergence insufficiency was the most prevalent.

Characterization of Visual Symptomatology Associated with Refractive, Accommodative, and Binocular Anomalies

Purpose. To characterize the symptomatology of refractive, accommodative, and nonstrabismic binocular dysfunctions and to assess the association between dysfunctions and symptoms. Methods. 175 randomised university students were examined. Subjects were given a subjective visual examination with accommodative and binocular tests, evaluating their symptomatology. Accommodative and binocular dysfunctions (AD, BD) were diagnosed according to the number of existing clinical signs: suspect AD or BD (one fundamental clinical sign), high suspect (one fundamental + 1 complementary clinical sign), and definite (one fundamental + 2 or more complementary clinical signs). A logistic regression was conducted in order to determine whether there was an association between dysfunctions and symptoms. Results. 78 subjects (44.6%) reported any kind of symptoms which were grouped into 18 categories, with “visual fatigue” being the most frequent (20% of the overall complaints). Logistic regression adjusted by the presence of an uncorrected refractive error showed no association between any grade of AD and symptoms. Subjects with BD had more likelihood of having symptoms than without dysfunction group (OR = 3.35), being greater when only definite BD were considered (OR = 8.79). Conclusions. An uncorrected refractive error is a confusion factor when considering AD symptomatology. For BD, the more the number of clinical signs used the greater the likelihood suffering symptoms.

A review of non-strabismic accommodative-vergence anomalies in school-age children. Part 1: Vergence anomalies

Comfortable reading and the performance of near point activities involve efficient accommodative and vergence systems. However, accommodative and vergence anomalies are associated with various symptoms that impair efficient near point tasks. Although several studies investigated accommodative-vergence anomalies in school-age populations, their findings were diverse owing to differences in diagnostic techniques and the criteria used to define the variables. The aim of this paper is to derive prevalence and distribution estimates of vergence anomalies in school-age children and address variations in the study methods and findings. Despite variations in the study methods and findings, accommodativevergence anomalies were common in school-age populations. Variations and limitations of previous studies are discussed and recommendations for improving future studies are suggested.

A review of non-strabismic accommodative and vergence anomalies in school-age children. Part 2: Accommodative anomalies

Comfortable reading and the performance of related near point activities involve efficient accommodative and vergence systems. However, accommodative and convergence anomalies are associated with various symptoms of asthenopia that impair efficient near point tasks. In Part 1 of this two-part article, studies on vergence anomalies were reviewed. In the current paper (Part 2), anomalies of accommodation are reviewed. The aims of the latter paper were to derive the prevalence and distribution estimates of anomalies of accommodation in school-age children and address variations in the study methods and findings. Despite variations in the study methods and findings, anomalies of accommodation are prevalent among school-age populations. Variations and limitations of previous studies are discussed and recommendations for improving future studies are suggested.

Symptomatology associated with accommodative and binocular vision anomalies

PURPOSE

To determine the symptoms associated with accommodative and non-strabismic binocular dysfunctions and to assess the methods used to obtain the subjects' symptoms.

METHODS

We conducted a scoping review of articles published between 1988 and 2012 that analysed any aspect of the symptomatology associated with accommodative and non-strabismic binocular dysfunctions. The literature search was performed in Medline (PubMed), CINAHL, PsycINFO and FRANCIS. A total of 657 articles were identified, and 56 met the inclusion criteria.

RESULTS

We found 267 different ways of naming the symptoms related to these anomalies, which we grouped into 34 symptom categories. Of the 56 studies, 35 employed questionnaires and 21 obtained the symptoms from clinical histories. We found 11 questionnaires, of which only 3 had been validated: the convergence insufficiency symptom survey (CISS V-15) and CIRS parent version, both specific for convergence insufficiency, and the Conlon survey, developed for visual anomalies in general. The most widely used questionnaire (21 studies) was the CISS V-15. Of the 34 categories of symptoms, the most frequently mentioned were: headache, blurred vision, diplopia, visual fatigue, and movement or flicker of words at near vision, which were fundamentally related to near vision and binocular anomalies.

CONCLUSIONS

There is a wide disparity of symptoms related to accommodative and binocular dysfunctions in the scientific literature, most of which are associated with near vision and binocular dysfunctions. The only psychometrically validated questionnaires that we found (n=3) were related to convergence insufficiency and to visual dysfunctions in general and there no specific questionnaires for other anomalies.

The Effect of an On-Site Vision Examination on Adherence to Vision Screening Recommendations

Vision screenings are intended to efficiently identify students with possible visual impairment and initiate a referral for diagnosis and treatment. In many cases, at-risk students do not access the recommended care or experience delays in receiving care. The purpose of this article is to report the effect on adherence to vision screening recommendations by providing the eye examination at the students’ school and at no cost. Of the 1,306 students screened, 382 (29.2%) were identified with possible visual impairment. Parental consent for examination was obtained for 198 (51.8%) students. Our vision screening and examination program yielded similar adherence to follow-up as stand-alone vision screening programs. Future program considerations should address perceptual barriers that may be contributing to parental nonadherence to vision screening recommendations.

Diagnostic validity of clinical signs associated with a large exophoria at near

Purpose. To analyze the diagnostic validity of accommodative and binocular tests in a sample of patients with a large near exophoria with moderate to severe symptoms. Methods. Two groups of patients between 19 and 35 years were recruited from a university clinic: 33 subjects with large exophoria at near vision and moderate or high visual discomfort and 33 patients with normal heterophoria and low visual discomfort. Visual discomfort was defined using the Conlon survey. A refractive exam and an exhaustive evaluation of accommodation and vergence were assessed. Diagnostic validity by means of receiver operator characteristic (ROC) curves, sensitivity (S), specificity (Sp), and positive and negative likelihood ratios (LR+, LR-) were assessed. This analysis was also carried out considering multiple tests as serial testing strategy. Results. ROC analysis showed the best diagnostic accuracy for receded near point of convergence (NPC) recovery (area = 0.929) and binocular accommodative facility (BAF) (area = 0.886). Using the cut-offs obtained with ROC analysis, the best diagnostic validity was obtained for the combination of NPC recovery and BAF (S  =  0.77, Sp = 1, LR+ = value tending to infinity, LR- = 0.23) and the combination of NPC break and recovery with BAF (S  =  0.73, Sp = 1, LR+ = tending to infinity, LR- = 0.27). Conclusions. NPC and BAF tests were the tests with the best diagnostic accuracy for subjects with large near exophoria and moderate to severe symptoms.

Patient-reported outcome measures (PROMs) in paediatric ophthalmology: a systematic review

AIM

To identify patient-reported outcome measures (PROMs) specifically developed and used to assess the impact of ophthalmic disorders in children and to systematically assess their quality as a basis for recommendations about their use in clinical and research settings.

METHODS

A systematic review of the literature was performed in MEDLINE, EMBASE, PsychINFO, CINAHL and AMED, supplemented by a grey literature search. Papers reporting development and validation of questionnaire instruments for assessing patient-reported outcomes of an ophthalmic disorder in patients aged 2-18 years were included. Quality was assessed by examining the purpose and psychometric properties of the instruments. Strengths and limitations were summarised with recommendations regarding use.

RESULTS

Search identified 17 instruments. Of these, 11 were condition-specific and six were intended for a broader population of children and young people with visual impairment regardless of the ophthalmic condition. Three were developed for use in a specific trial and two are still in development.

CONCLUSIONS

Paediatric ophthalmology PROM development and application is a developing field and new instruments are needed. There is scope for improvement in this area through (a) clarity of definitions of the underlying constructs intended to be measured at the onset of development of new instruments, (b) application of child-centred approaches and (c) adherence to extant guidance and best practice in questionnaire instrument development.

COVD-QOL questionnaire: An adaptation for school vision screening using Rasch analysis

Purpose

To adapt the College of Optometrist in Vision Development (COVD-QOL) questionnaire as a vision screening tool for primary school children.

Methods

An interview session was conducted with children, teachers or guardians regarding visual symptoms of 88 children (45 from special education classes and 43 from mainstream classes) in government primary schools. Data was assessed for response categories, fit items (infit/outfit: 0.6–1.4) and separation reliability (item/person: 0.80). The COVD-QOL questionnaire results were compared with vision assessment in identifying three categories of vision disorders: reduce visual acuity, accommodative response anomaly and convergence insufficiency. Analysis on the screening performance using the simplified version of the questionnaire was evaluated based on receiver-operating characteristic analysis for detection of any type of target conditions for both types of classes. Predictive validity analysis was used a Spearman rank correlation (>0.3).

Results

Two of the response categories were underutilized and therefore collapsed to the adjacent category and items were reduced to 14. Item separation reliability for the simplified version of the questionnaire was acceptable (0.86) but the person separation reliability was inadequate for special education classes (0.79) similar to mainstream classes (0.78). The discriminant cut-off score of 9 (mainstream classes) and 3 (special education classes) from the 14 items provided sensitivity and specificity of (65% and 54%) and (78% and 80%) with Spearman rank correlation of 0.16 and 0.40 respectively.

Conclusion

The simplified version of COVD-QOL questionnaire (14-items) performs adequately among children in special education classes suggesting its suitability as a vision screening tool.

Effectiveness of vision therapy for convergence dysfunctions and long-term stability after vision therapy

BACKGROUND

Symptomatic convergence insufficiency (CI) is a common binocular dysfunction. It is often associated with accommodative insufficiency (AI). Optimum therapy for this condition was recently shown to be in-clinic vision therapy (VT). More scientific studies are needed to assess the effectiveness of VT and verify these evidence-based results.

METHODS

Fifty-seven children aged 9-13 years were diagnosed with symptomatic CI (n = 27) or combined symptomatic CI and AI (n = 30). They were independently divided into a treatment and a control group, matched by age and gender. The treatment group received 12 weeks of VT while the control group received no therapy. A quality of life instrument documented the symptomatic patients and charted improvement in symptoms after therapy. Clinical aspects were also assessed to determine the treatment effects on clinical findings. Twenty children in the treatment group completed a 1 year follow-up examination.

RESULTS

Symptom scores and clinical measures of the treatment and control groups were not significantly different at baseline (p > 0.05), but showed significant differences after completion of 12 weeks of treatment (p < 0.001). No significant changes of either symptoms or signs were evident for the control group. One year follow-up examination revealed that most children maintained the improved symptom and clinical measures after VT.

CONCLUSION

This study supports the notion that VT is a successful method of treating CI and CI combined with AI.

Disorders of vergence eye movements

PURPOSE OF REVIEW

The aim is to re-interpret disorders of vergence in the light of recent studies that view disjunctive eye movements as but one component of three-dimensional gaze control.

RECENT FINDINGS

Most natural eye movements combine vergence with saccades, pursuit and vestibular eye movements. Electrophysiological studies in epileptic patients, as well as evidence from monkeys, indicate that frontal and parietal cortex govern vergence as a component of three-dimensional gaze. Clinicians apply Hering's law of equal innervation to interpret disjunctive movements as the superposition of conjugate and vergence commands. However, electrophysiological studies indicate that disjunctive saccades are achieved by programming each eye's movement independently. Patients with internuclear ophthalmoplegia (INO) may have preserved vergence, which can be recruited to compensate for loss of conjugacy. Vergence may also enable gaze shifts in saccadic palsy. Some forms of nystagmus suppress or change with convergence; co-contraction of the horizontal rectus muscles does not appear to be the explanation. Rather, effects of near viewing on central vestibular mechanisms or differential activation of specific types of extra-ocular muscle fiber may be responsible.

SUMMARY

Interpretation of disorders of vergence is aided by applying a scheme in which their contributions to three-dimensional gaze control is considered.

An analysis of vision screening data from New York City public schools

OBJECTIVE

This study compares different vision screening batteries and documents the failure rates of different vision tests in children who receive periodic vision screenings.

METHODS

Vision screenings were conducted on 1,992 preschool through fifth grade children attending schools in lower socioeconomic areas in New York City. The screening battery incorporated visual acuity, retinoscopy, cover test, stereopsis, near point of convergence, ocular motility, accommodation, color vision, and ocular health.

RESULTS

Slightly less than one third (30%) of the children screened failed the State University of New York (SUNY) battery and were referred for a comprehensive examination, of which 249 (41%) children actually passed distance visual acuities. The referral rate for distance visual acuity alone was 19%. The referral rate for the Modified Clinical Technique (MCT) was 22%. A greater percentage (33%) of the children in grades kindergarten through fifth were referred compared with the preschoolers (20%). Only a small percentage (8%) of the children wore corrective lenses at the time of testing. There was a significant increase in the prevalence of binocular vision problems found in children from grades kindergarten through 5.

CONCLUSIONS

Poor visual acuity and binocular vision problems exist in schoolchildren despite ongoing vision screenings. The results provide evidence for the necessity of periodic rescreening starting in kindergarten and the importance of screening for hyperopia and binocular vision problems in addition to distance visual acuities.