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

Short-Term Effect of Spinal Manipulation on the Magnitude of Exophoria in Adults Who Are Asymptomatic: A Randomized Controlled Trial

OBJECTIVE

This study aimed to assess the immediate and short-term effects of cervical spinal manipulation (SM), compared with a placebo, on the magnitude of near and distance exophoria in adults with asymptomatic exophoria.

METHODS

In this single-blind, randomized controlled trial, individuals with a clinical diagnosis of horizontal exophoria confirmed with the prism alternating cover test (PACT) were allocated to a single intervention session using a high-velocity, low-amplitude cervical SM technique or a sham intervention (manual contact under the head). Outcomes were the magnitude of horizontal heterophoria, as a measure of binocular vision efficiency at near (40 cm) or distance (4 m) fixation, using the PACT. Evaluations were made at baseline, immediately after intervention, and at a 1-week follow-up.

RESULTS

From May to September 2021, 44 volunteers (23 women), with a mean age of 35 (SD = 9.5) years, were recruited and equally distributed into the study groups. All participants completed follow-up assessments, and no adverse events were reported. There was a significant time × group interaction for exophoria at near vision, but not at distance fixation. The SM group showed a significant decrease of near exophoria compared with the control group at the 1-week follow-up (mean difference = -1.09 prism diopters; 95% CI = -0.20 to -1.98 prism diopters).

CONCLUSION

The use of cervical SM therapy resulted in a significant reduction of the magnitude of horizontal exophoria at near vision (medium effect size), compared with the placebo, in young adults who are asymptomatic. However, these effects were not observed at distance fixation and should be considered cautiously due to the pre-post design with a single intervention session and the short-term follow-up.

IMPACT

The findings suggest short-term benefits of SM therapy can manage undiagnosed ocular convergence disorders, although changes were not clinically relevant.

Horizontal Heterophoria Modifications by Means of Thin Proprioceptive Stimulations Applied on the Foot Sole: A Randomised Study

Some authors have demonstrated that proprioceptive stimuli applied on the feet soles can interfere on the ocular muscles. However, these studies do not clarify possible functional differences between the dominant eye and the non-dominant eye. The purpose of this randomised study is to establish if the positioning of an Internal Heel Wedge (IHW) and an External Heel Wedge (EHW) can modify horizontal heterophoria, determine dissimilar behaviours between the dominant eye and the non-dominant eye. Forty-two healthy subjects, with a right dominant eye, were tested. The 1.5 mm-thick proprioceptive stimuli were shaped out of a cork half-moon. The experimental group was divided into two groups: IHW group and EHW group. Both groups performed the "Baseline" (without mechanical stimulation) and "After 15'" (following a fitting period of 15 minutes on a treadmill with mechanical stimulation) trials. The control group performed the same trials without any podalic stimulation. Meaningful changes were observed on the horizontal heterophoria of the non-dominating eye with an IHW. Non-statistically significant variations were observed with an EHW and in the Control group. A thin heel wedge applied on the foot sole was able to generate functional changes in the non-dominant eye and could help health professionals develop increasingly personalised rehabilitation programmes.

Prevalence of binocular vision dysfunctions in professional football players

CLINICAL RELEVANCE

The extent of binocular vision dysfunction in elite soccer players needs to be determined as it may impact performance.

BACKGROUND

The purpose of the study was to investigate the prevalence of binocular vision dysfunctions in elite soccer players.

METHODS

One hundred and seven professional soccer players were evaluated. Refractive error was measured and the following binocular vision parameters were assessed: horizontal and vertical phoria for distance and near vision, the values of break and recovery for negative and positive fusional vergences at distance and near vision, vergence facility at distance and near vision, monocular accommodative facility at near vision, and near point of convergence (break and recovery points). All the athletes were men with a mean age of 24.4 ± 4.8 years.

RESULTS

No athlete was diagnosed with divergence excess, divergence insufficiency, or basic exophoria. About 13.0% of the athletes have binocular vision dysfunctions related to esophoria (0.9% with esophoria at near vision and 12.1% with esophoria at distance and near vision). About 10.3% have convergence insufficiency and 2.8% were diagnosed with fusional vergence dysfunction. The only accommodation-related parameter analysed was accommodative infacility, and 6.5% of the athletes had this dysfunction. Vertical phoria was present in 3.7% of the athletes. No statistically significant differences were found based on in athletes with respect to ethnicity, position occupied on the field, age, ametropia or laterality.

CONCLUSION

The overall prevalence of binocular vision dysfunction in elite soccer players was 36.4%. The most prevalent dysfunctions are related to the presence of esophoria (13.0%). The values found point out the need to include binocular vision assessment protocols in the visual assessment routine for athletes.

Effect of corneal refractive surgery on accommodative and binocular dysfunctions among civilian pilots in Southwest China

Background

To analyze whether corneal refractive surgery (CRS) is associated with the distribution of different accommodative dysfunctions (ADs) and binocular dysfunctions (BDs) in civilian pilots. A further aim was to analyze the percentages and visual symptoms associated with ADs and/or BDs in this population.

Methods

One hundred and eight civilian pilots who underwent CRS from January 2001 to July 2012 (age: 30.33 ± 4.60 years) were enrolled, the mean preoperative SE was − 1.51 ± 1.15 D (range: − 1.00- − 5.00 D). Ninety-nine emmetropic civilian pilots (age: 29.64 ± 3.77 years) who were age- and sex-matched to the CRS group were also enrolled. Refractive status, accommodative and binocular tests of each subject were performed. Visually related symptoms were quantified using the 19-item College of Optometrists in Vision Development Quality of Life (COVD-QOL) questionnaire. The 19 items were summed to obtain visual symptom scores that might indicate visual dysfunctions. The chi-square test was used to analyze differences in percentages of ADs and/or BDs between the CRS and emmetropic groups. The Mann-Whitney U test was used to compare visual symptom scores between pilots with ADs and/or BDs and pilots with normal binocular vision.

Results

No significant difference was observed between the CRS and emmetropic groups in the overall prevalence of ADs and BDs (15.7% and 15.2% in the CRS and emmetropic groups, respectively; P = 0.185). ADs were present in 4.63% and 3.03% of the CRS and emmetropic group, respectively. BDs were observed in 11.1% and 12.1% of the CRS and emmetropic group, respectively, yielding no significant differences between the groups in the prevalence of ADs or BDs (AD: P = 0.094; BD: P = 0.105). Pilots with ADs and/or BDs had significantly more visual symptoms than pilots with normal binocular vision (p < 0.001).

Conclusions

CRS for civilian pilots with low-moderate myopia might not impact binocular functions. ADs and/or BDs commonly occur in both emmetropia pilots and pilots who undergo CRS, and pilots with ADs and/or BDs are associated with increased symptoms. This study confirms the importance of a full assessment of binocular visual functions in detecting and remedying these dysfunctions in this specific population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01855-0.

Visual Binocular Disorders and Their Relationship with Baropodometric Parameters: A Cross-Association Study

The aim of this study was to establish a relationship between nonstrabismic binocular dysfunction and baropodometric parameters. A total of 106 participants underwent binocular vision assessment by evaluating horizontal heterophoria, horizontal and vertical fusional vergence ranges, and vergence facility. Posturography was measured using the FreeMED baropodometric platform. Among the variables that the software calculates are foot surface, foot load, and foot pressure. Our results showed that in the participants with positive fusional vergence (PFV) (near) blur and recovery values outside the norm, there are statistically significant differences between the total foot area (p < 0.05), forefoot area (p < 0.05), forefoot load (p < 0.05), and rearfoot load (p < 0.05), in all of the cases of left foot vs. right foot. In the group of subjects who did not meet Sheard's criterion (distance), that is, those with unstable binocular vision, there was a statistically significant difference (p < 0.01) between maximum left and right foot pressure. In conclusion, our results establish a relationship between nonstrabismic binocular dysfunctions and some baropodometric parameters.