Maintenance of normal fusion in intermittent exotropia

PURPOSE

To evaluate the reliability of the Bagolini filter bar and striated lenses for measuring the fusion maintenance score, which is the ability of participants with intermittent exotropia to maintain normal sensorimotor fusion.

METHODS

Thirty-two Chinese participants aged 7-20 years with intermittent exotropia (excluding the convergence insufficiency type) were enrolled in this prospective study. At the eligibility screening, visual acuity, cover test and assessment of the office control score were performed. At study visit 1, eligible participants underwent negative and positive fusional vergence tests at far and near, eye dominance test and the fusion maintenance test. All eligible participants returned for study visit 2 on the same day (2-4 h later) and the testing was repeated. The primary outcome measure was the intra-class correlation coefficient of the fusion maintenance score between the two study visits.

RESULTS

The intra-class correlation coefficient of the fusion maintenance score was 0.84, indicating good reliability. There was no significant difference (mean difference = 0.05, p = 0.95) between the fusion maintenance scores for the first (5.62) and second study visits (5.57). The coefficient of repeatability and the smallest detectable change for the fusion maintenance scores were 7.6 and 6.3, respectively. The fusion maintenance score was significantly associated with the distance (Spearman correlation -0.57, p < 0.001) and near (Spearman correlation -0.4, p = 0.02) office control scores.

CONCLUSION

These data demonstrate that the fusion maintenance score is a reliable tool to evaluate sensorimotor fusion in intermittent exotropia. These results suggest that the fusion maintenance score may be a useful outcome measure in future clinical trials to evaluate the effectiveness of treatments for intermittent exotropia.

Prevalence of heterophoria in a population of school children in central China: the Anyang Childhood Eye Study

AIM

To investigate the prevalence of heterophoria and the relationship between heterophoria and refractive error in a school-based study conducted in central China.

METHODS

A total of 2363 7^th-grade children were recruited into the cross-sectional school-based Anyang Childhood Eye Study (ACES) by cluster sampling method. Heterophoria was examined using alternate cover and cover-uncover testing. The Maddox rod and prism test were conducted at 33 cm and 6 m distance fixation. Uncorrected viual acuity (UCVA) and best-corrected viual acuity (BCVA) were recorded as logarithm of the minimum angle of resolution (logMAR) with cycloplegic autorefraction by administrating of Mydrin-P and 1.0% cyclopentolate. Hyperopia was defined as the spherical equivalent (SE) refraction of +0.50 D or greater, and higher hyperopia was defined as +2.00 D or greater. Emmetropia was defined as the SE refraction in the range of -0.49 to +0.49 D, and myopia was in the SE refraction range from -0.50 D to less.

RESULTS

Totally 2260 students in grade 7 were examined. Response rate among eligible children was 95.64%. Totally 486 children, 22.66% of the population, were diagnosed with heterophoria in which 479 were diagnosed with exophoria at near distance, and 6 with esophoria. Totally 89 (4.15%) children were diagnosed with heterophoria in which 82 had exophoria, and 7 had esophoria at far distance. Exophoria was common at near fixation (22.33%). Myopia was examined to be related to exophoria at near distance (OR 3.03, 95%CI 2.33-3.95) and far distance fixation (OR 1.90, 95%CI 1.09-3.32).

CONCLUSION

Exophoria is a predominant heterophoria for 7^th-grade junior school in central China. Significant associations are discovered between heterophoria and refractive error. Hyperopia is associated with esophoria, and myopia is associated with exophoria.

Distance associated heterophoria measured with polarized Cross test of MKH method and its relationship to refractive error and age

PURPOSE

Due to the expansion of modern optotype liquid crystal display with the help of positive polarization, measurement of heterophorias (HTFs) by means of polarization, and thus partial dissociation of perceptions, has become more and more accessible. Our aims were to establish the prevalence of distance associated HTF by measuring with polarized Cross test of MKH [measuring and correcting methodology after H-J Haase] method and its association with age and refractive error in clinical population of wide age range.

METHODS

A cross-sectional study was carried out with 170 clinical subjects aged 15-78 years with an average age of 40.7±16.62 years. All the participants had best-corrected visual acuity better than 20/25, stereopsis ≤60 second of arc, no heterotropia, not undergone vision therapy, and had no eye disease. The distance associated HTF was measured with the Cross test of the MKH methodology. The quantification of associated HTF was acquired by means of Risley rotary prism.

RESULTS

The occurrence of distance associated HTF was found in 71.2% of participants. Of the total, 36.5% of the cases had esophoria (EP), 9.4% EP and hyperphoria, 10.6% exophoria (XP), 7.1% XP and hyperphoria, 7.6% hyperphoria, and 28.8% orthophoria. The mean distance horizontal associated HTF was +0.76±2.38 Δ. With EP, the mean value was +2.47±2.18 Δ, and with XP, -2.1±1.72 Δ. There was no correlation observed between the amount of distance associated HTF and age. There was no effect of the type and amount of a refractive error on the amount of distance associated HTF.

CONCLUSION

A high occurrence of distance associated HTF was revealed while performing the polarized Cross test of MKH method. The relationship between the degree of associated HTF and refractive error and age was not proved.

Variability of Fusion Vergence Measurements in Heterophoria

PURPOSE

The aims of this study were to compare fusional vergence measurements between orthophoria, esophoria, and exophoria, and to determine the strength of correlations between fusional convergence and divergence and angle of deviation.

METHODS AND MATERIALS

A cross-sectional study was performed in children with best-corrected visual acuity of 0.0 LogMAR in either eye, compensated heterophoria within 10 prism diopters (PD), full ocular rotations, presence of fusional vergence, and stereopsis (60 seconds of arc or better). Fusional amplitudes were compared between orthophoric and heterophoric children. The fusion reserve ratio was determined as compensating vergence divided by alternating cover test.

RESULTS

Five hundred and thirty children (7.66±1.20 years) were recruited to this study. The most common heterophoria was exophoria (n=181, 34.2% for near; n=20, 3.8% for distance). Exophoric children had significant lower mean positive fusional vergences (exophoria-orthophoria: P=0.003; exophoria-esophoria: P=0.035) for near (19.54±5.23 base-out) compared with children with orthophoria (20.48±4.83 base-out) and esophoria (22.27±5.60 base-out). Smaller convergence fusion amplitudes were associated with larger angles of deviation at near (rs=-0.115; P=0.008) and lower fusion reserve ratios were associated with larger angles of deviation at distance (rs=-0.848; P<0.001) and at near (rs=-0.770; P<0.001).

CONCLUSIONS

Exophoric children have reduced convergence break points when compared with orthophoric and esophoric children. Vergence measurements, taking into consideration the baseline heterophoria, give important information about the ability of the patient to increase their vergence demand and maintain ocular alignment.

Relief of asthenopic symptoms with orthoptic exercises in convergence insufficiency is achieved in both adults and children

Background

Asthenopic symptoms associated with convergence insufficiency (CI) may compromise a person's ability to work or study. We investigated the effectiveness of orthoptic exercises in relieving symptoms related to CI and long-time results in adults and children.

Methods

The data were retrospectively gathered from the patient clinical files. A total of 135 patients met the inclusion criteria of suffering asthenopic symptoms and CI but had not received prior strabismus surgery or orthoptic exercises.

Results

The mean age was 26 ± 17 years, 74% of them were female. The patients (N = 135) suffered from CI and had at least one of the following symptoms: eyestrain, blurring of vision, problems in reading and while doing work-up at close distance or headache. In the two-year follow-up time, 4% of the patients needed to be retreated and 3% of the patients required strabismus surgery. There were no significant differences between adults and children in near point of convergence (NPC), number of visits needed or fusional vergence at the end of treatment nor did the outcome depend on the number of visits. 59.5% of children vs. 51.9% of adults were free of symptoms when completing the exercises.

Conclusions

In conclusion orthoptic exercises are effective in relieving asthenopic symptoms in adults and children. The effects of orthoptic exercises on NPC and fusional vergence were equal in adults and in children and not dependent on the number of visits needed for successful outcome. With orthoptic exercises it is possible to achieve longstanding relief on the symptoms of CI.

Randomized clinical trial of treatments for symptomatic convergence insufficiency in children

OBJECTIVE

To compare home-based pencil push-ups (HBPP), home-based computer vergence/accommodative therapy and pencil push-ups (HBCVAT+), office-based vergence/accommodative therapy with home reinforcement (OBVAT), and office-based placebo therapy with home reinforcement (OBPT) as treatments for symptomatic convergence insufficiency.

METHODS

In a randomized clinical trial, 221 children aged 9 to 17 years with symptomatic convergence insufficiency were assigned to 1 of 4 treatments.

MAIN OUTCOME MEASURES

Convergence Insufficiency Symptom Survey score after 12 weeks of treatment. Secondary outcomes were near point of convergence and positive fusional vergence at near.

RESULTS

After 12 weeks of treatment, the OBVAT group's mean Convergence Insufficiency Symptom Survey score (15.1) was statistically significantly lower than those of 21.3, 24.7, and 21.9 in the HBCVAT+, HBPP, and OBPT groups, respectively (P < .001). The OBVAT group also demonstrated a significantly improved near point of convergence and positive fusional vergence at near compared with the other groups (P

CONCLUSIONS

Twelve weeks of OBVAT results in a significantly greater improvement in symptoms and clinical measures of near point of convergence and positive fusional vergence and a greater percentage of patients reaching the predetermined criteria of success compared with HBPP, HBCVAT+, and OBPT. Application to Clinical Practice Office-based vergence accommodative therapy is an effective treatment for children with symptomatic convergence insufficiency.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00338611.

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Key Words

• convergence insufficiency
• asthenopia
• vision therapy
• orthoptics
• vergence/accommodative therapy
• pencil push-ups
• computer vergence/accommodative therapy
• placebo therapy
• exophoria
• eyestrain
• symptom survey

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MESH Headings

• Adolescent
• Child
• Confidence Intervals
• Convergence, Ocular
• Female
• Home Nursing
• Humans
• Male
• Multivariate Analysis
• Ocular Motility Disorders/diagnosis
• Ocular Motility Disorders/therapy
• Office Visits
• Ophthalmology/methods
• Orthoptics/methods
• Patient Compliance
• Probability
• Recovery of Function
• Reference Values
• Sensitivity and Specificity
• Severity of Illness Index
• Strabismus/diagnosis
• Strabismus/therapy
• Treatment Outcome
• Vision, Binocular
• Visual Acuity

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Grants

• U10 EY014712 NEI NIH HHS
• U10 EY014676-02 NEI NIH HHS
• U10 EY014712-04 NEI NIH HHS
• U10 EY014659-03 NEI NIH HHS
• U10 EY014676-01A1 NEI NIH HHS
• U10 EY014713-01A2 NEI NIH HHS
• U10 EY014713-02 NEI NIH HHS
• U10 EY014715-01A1S1 NEI NIH HHS
• U10 EY014716-04 NEI NIH HHS
• U10 EY014710-04 NEI NIH HHS
• U10 EY014676 NEI NIH HHS
• U10 EY014706-01A1S1 NEI NIH HHS
• U10 EY014713 NEI NIH HHS
• U10 EY014709 NEI NIH HHS
• U10 EY014659-01A2 NEI NIH HHS
• U10 EY014715-04 NEI NIH HHS
• U10 EY014712-01A1 NEI NIH HHS
• U10 EY014713-03 NEI NIH HHS
• U10 EY014706-01A1 NEI NIH HHS
• U10 EY014715-02 NEI NIH HHS
• U10 EY014709-03 NEI NIH HHS
• U10 EY014715-03 NEI NIH HHS
• U10 EY014676-04 NEI NIH HHS
• U10 EY014715 NEI NIH HHS
• U10 EY014716-03 NEI NIH HHS
• U10 EY014710-02 NEI NIH HHS
• U10 EY014709-04 NEI NIH HHS
• U10 EY014716-02 NEI NIH HHS
• U10 EY014716-02S1 NEI NIH HHS
• U10 EY014706-02 NEI NIH HHS
• U10 EY014713-04 NEI NIH HHS
• U10 EY014709-02 NEI NIH HHS
• U10 EY014712-03 NEI NIH HHS
• U10 EY014706-04 NEI NIH HHS
• U10 EY014710-01A1S1 NEI NIH HHS
• U10 EY014710-01A1 NEI NIH HHS
• U10 EY014659-04 NEI NIH HHS
• U10 EY014676-03 NEI NIH HHS
• U10 EY014712-01A1S1 NEI NIH HHS
• U10 EY014659-02 NEI NIH HHS
• U10 EY014676-01A1S1 NEI NIH HHS
• U10 EY014716-01A1 NEI NIH HHS
• U10 EY014709-01A1 NEI NIH HHS
• U10 EY014706-03 NEI NIH HHS
• U10 EY014716-01A1S1 NEI NIH HHS
• U10 EY014716 NEI NIH HHS
• U10 EY014715-01A1 NEI NIH HHS
• U10 EY014709-01A1S1 NEI NIH HHS
• U10 EY014712-02 NEI NIH HHS
• U10 EY014710-03 NEI NIH HHS
• U10 EY014659 NEI NIH HHS

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