Walking strategies in subjects with congenital or early onset strabismus

The effect of strabismus surgery on the dynamic balance in children with strabismus

Purpose: To evaluate the effect of strabismus surgery on dynamic balance by using computerized dynamic posturography in children with strabismus. Methods: This study was designed as a prospective observational study. Hearing tests and complete ophthalmological examinations were performed for all subjects. Patients with moderate and severe amblyopia, hearing loss at any level, and/or any suspicion of balance impairment were excluded from the study. Postural stability evaluation was performed by computerized dynamic posturography including sensory organization test, adaptation test, and rhythmic weight shift test. All tests were applied preoperatively and in the postoperative 1st and 3rd months, respectively. Results: Fifteen female and twelve male pre-adolescents aged between 7 and 12 (9.67 ± 1.62 years) were included in the current study. In the sensory organization test, the preoperative visual ratio percentages (73.19 ± 14.95%) improved statistically significantly at the postoperative 1st and 3rd months (78.59 ± 16.21% and 81.44 ± 14.18; p = .026, p = .021, respectively). The preoperative toes up (110.66 ± 33,48) and toes down (81.46 ± 28.36) adaptation tests improved statistically significantly in the postoperative 3rd month (88.74 ± 20.94 and 63.36 ± 16.03; p < .001, p = .001, respectively). In the Rhythmic Weight Shift test, the postoperative 3rd-month directional control (forward-backward) value (74.25 ± 11.51%) was statistically significantly higher compared to the preoperative directional control (forward-backward) value (67.76 ± 11.38%) (p = .011). The postoperative 3rd-month directional control (forward-backward) value (74.25 ± 11.51%) was statistically significantly higher compared to the postoperative 1st-month directional control (forward-backward) value (68.43 ± 14.00%) (p = .028). Conclusion: Surgical treatment resulted in an improvement in the maintenance of dynamic balance in children with strabismus.

Strabismus Surgery Decreases the Risk of Injuries in Pediatric Patients in the OptumLabs Data Warehouse

PURPOSE

Previous studies have shown an association between injury risk and strabismus in aged Medicare beneficiaries and children. The injury prevalence in strabismic children was 30% in a study of >10 million patients in the OptumLabs Data Warehouse. The purpose of this study was to determine whether strabismus surgery decreases the risk of injury.

DESIGN

Retrospective cohort study.

METHODS

The OptumLabs Data Warehouse is a deidentified, longitudinal health database that was queried for strabismic patients aged <19 years. The patients who underwent strabismus surgery were compared with those strabismic patients who did not undergo surgery for injury. Injury risk (fractures, musculoskeletal injuries, and head injuries) during their insurance enrollment was calculated in the nonsurgical patients after their first strabismus claim and compared with the risk in surgical patients postoperatively.

RESULTS

There were 344,794 patients with strabismus. Surgery was performed in 26,459 (7.7%). Esotropia was the most common diagnosis (n = 181,195, 52.6%) followed by exotropia (n = 161,712, 46.9%) and hypertropia (n = 43,831, 12.7%). Within these groups, patients with hypertropia were significantly more likely to undergo surgery (24.2%) compared with patients with esotropia and exotropia (10.2% and 9.6%, respectively). Injuries were diagnosed after the first strabismus claim in 94,960 (29.8%) nonsurgical patients vs 5790 (21.9%) postsurgical patients (P < .001) with a mean follow-up of 4.3 ± 3.1 vs 3.8 ± 3.1 years, respectively. The adjusted hazard ratio for injuries was 0.85 (95% confidence interval [CI]: 0.83-0.87) for the risk of any injury after strabismus surgery. The hazard ratio was significantly decreased after surgery for each type of strabismus: esotropia (0.91, 95% CI: 0.88-0.94), exotropia (0.82, 95% CI: 0.80-0.85), and hypertropia (0.89, 95% CI: 0.85-0.93).

DISCUSSION

Strabismus surgery was associated with a 15% decrease in the risk of physical injury over approximately 4 years of follow-up. Surgery may be a factor in decreasing injury risk in strabismic patients, particularly in exotropia. Given the large number of children with strabismus in the United States, further assessment of strategies such as strabismus surgery to reduce injuries in children with strabismus is needed.

Deficient vergence prism adaptation in subjects with decompensated heterophoria

Vergence prism adaptability was evaluated in subjects with high symptomatic and asymptomatic heterophoria and compared to individuals with a heterophoria within normal range (the control group). A computer haploscope was used to measure phoria values and changes in the eye position after introducing 6 prism diopters base out in front of the right eye. Phoria values were measured with a nonius paradigm every minute for a period of 10 minutes during adaptation. The results showed that subjects with symptomatic heterophoria are characterized by a lower rate of prism adaptation and adapted to a smaller extent with respect to the control group. The group with high but asymptomatic heterophoria showed prolonged adaptation time but after several minutes of binocular viewing the subjects were able to adapt to the prism to a level similar to the control group. These findings suggest that an impairment in the slow vergence control system may be responsible for the inability to fully reduce vergence effort, which results in poor vergence ranges and asthenopic symptoms during prolonged viewing.

Balance in subjects with congenital or early onset strabismus: Influence of age

Few studies have investigated the relationship between strabismus and balance, and those that do exist focused on patients within a limited age range, while no studies on possible age-related changes have yet been conducted. Therefore, the aim of our study was to investigate whether the balance strategies adopted by patients with congenital or early onset strabismus change with age. Forty strabismic patients and 36 healthy subjects were enrolled in the study. Both patients and healthy subjects were divided into three subgroups according to age (children, adolescents, and adults) and underwent a stabilometric evaluation. When we compared the whole group of strabismic patients with the group of healthy subjects, we found that the center of pressure area and the trunk oscillations in the former were significantly different from those in the latter; when we considered the three age groups separately, only values in children with strabismus were different from those in the age-matched control group of healthy subjects. Strabismus was found to affect balance in children by inducing a postural strategy characterized by a reduction in physiological trunk oscillations. Gaining a better insight into postural control in strabismic subjects and its evolution with age may be crucial to improving rehabilitation in such patients and planning tailored rehabilitation treatment.