Effectiveness of vergence/accommodative therapy for accommodative dysfunction in children with convergence insufficiency

Effects of Two Vision Therapy Approaches on Accommodative Insufficiency and Post-therapy Stability

PURPOSE

To evaluate the effect of the EYEPORT II vision training system (Bernell) on accommodation in cases of accommodative insufficiency.

METHODS

The experimental study was conducted in a binocular vision clinic. Of 230 patients, 36 were eligible and willing to participate in office-based therapy. Participants were randomly divided into two groups: control and EYEPORT. The control group received conventional therapy and the EYEPORT group received conventional therapy combined with the EYEPORT II vision training device. The therapy lasted for 1 hour daily over 6 days in a week, with 24 sessions administered over 4 weeks. Accommodative parameters were reevaluated 2 weeks, 4 weeks, and 3 months after treatment.

RESULTS

The study included 19 men and 17 women, with a median age of 27.50 years. After 24 sessions of vision therapy, accommodative parameters improved significantly, with more pronounced results compared with baseline measurements, as demonstrated by the Wilcoxon signed-rank test (P < .05). The Mann-Whitney U test indicated a significant (P < .05) improvement in treatment outcomes for the EYEPORT group using the EYEPORT device together with conventional therapy. The median accommodation amplitude increased by 6.95 diopters (D), the accommodation lag decreased by -0.25 D, the positive relative accommodation improved by -1.63 D, and the accommodative facility increased by 13 cycles/minute. After 3 months without therapy, the treatment outcome was maintained.

CONCLUSIONS

Office-based vision therapy can effectively treat accommodative insufficiency. Both groups showed improvement in the accommodative amplitude and other parameters. The EYEPORT group was more stable at 3 months. [J Pediatr Ophthalmol Strabismus. 20XX;XX(X):XXX-XXX.].

Professional perspective of vision therapy worldwide among optometrists and ophthalmologists

CLINICAL RELEVANCE

Perception of optometrists and ophthalmologists of vision therapy (VT) as well as their methods for performing the sessions is of great importance for understanding the problems that professionals face and what should be improved in their clinical practice.

BACKGROUND

The objective of this study was to determine the perception of VT and protocols used by eye care professionals globally.

METHODS

A cross-sectional study was performed among eye care professionals internationally. The participants completed via online (Google Forms) a questionnaire of 40 questions on their perception and clinical practice of VT. The survey only permitted one answer per email address and was only collected if professionals gave their consent to participate.

RESULTS

A total of 205 professionals from 43 countries answered the questionnaire (171 optometrists and 34 ophthalmologists). Accommodation and convergence problems were the main indication reported for VT (47.8%), followed by amblyopia (26.3%). The principal negative factor associated to VT was the limited number of professionals dedicated to this field (55.6%). The most common program of VT was the combination of VT sessions at home and at office (85.5%), with a great variability in terms of duration. Few professionals made use of the new technologies when programming VT, such as eye trackers (2.7%) or virtual reality (6.4%). European professionals surveyed had a more negative perception of VT (p < 0.031).

CONCLUSIONS

Eye care professionals globally perceive VT as a scientifically based procedure. Overall, they believe that it has low recognition and prestige, especially ophthalmologists. A great variability in the programming of VT sessions was found, which highlights the need for standardised protocols that professionals could follow in their clinical practice.

Accommodative-vergence disorders in a paediatric ophthalmology clinical setting in Argentina

PURPOSE

To determine the frequency of potential non-strabismic accommodative-vergence anomalies (NSAVA) and investigate associations between NSAVA, refractive errors and age among children attending a paediatric ophthalmology clinic.

METHODS

This study included children and adolescents aged 5-19 years attending an ophthalmology clinic with at least two follow-up visits. At their first visit, children had a comprehensive ophthalmic examination, including refractive error measurement by cycloplegic autorefraction and spectacles were prescribed if necessary. At the second visit, children had an examination of best-corrected visual acuity, convergence and accommodation to identify potential NSAVA. The relationship between age, sex, heterophoria and refractive error and potential NSAVA was assessed by a multivariable logistic regression model.

RESULTS

A total of 384 children and adolescents were evaluated. Their mean age was 10.97 ± 3.07 years and 58.9% were females. Forty-two per cent of children failed the NSAVA tests and 34.1% had myopia (≤-0.50 D). Children who failed NSAVA tests self-reported a higher proportion of reading problems (73.7%) compared to those who passed the tests (26.3%; p < 0.001). Children with self-reported reading problems were more likely to have accommodative infacility (57.9%) compared with children without (42.1%; p < 0.001). Refractive error and age were not associated with failure in NSAVA tests (p > 0.05).

CONCLUSIONS

NSAVA was a frequent cause of vision problems found in a sample of children from an ophthalmology paediatric clinic. Thus, further research is necessary to understand the potential of public health policies to prevent, refer, diagnose and treat those conditions.

Impact of accommodative insufficiency and accommodative/vergence therapy on ciliary muscle thickness in the eye

PURPOSE

Recent evidence suggests that the ciliary muscle apical fibres are most responsive to accommodative load; however, the structure of the ciliary muscle in individuals with accommodative insufficiency is unknown. This study examined ciliary muscle structure in individuals with accommodative insufficiency (AI). We also determined the response of the ciliary muscle to accommodative/vergence therapy and increasing accommodative demands to investigate the muscle's responsiveness to workload.

METHODS

Subjects with AI were enrolled and matched by age and refractive error with subjects enrolled in another ciliary muscle study as controls. Anterior segment optical coherence tomography was used to measure the ciliary muscle thickness (CMT) at rest (0D), maximum thickness (CMTMAX) and over the area from 0.75 mm (CMT0.75) to 3 mm (CMT3) posterior to the scleral spur of the right eye. For those with AI, the ciliary muscle was also measured at increasing levels of accommodative demand (2D, 4D and 6D), both before and after accommodative/vergence therapy.

RESULTS

Sixteen subjects with AI (mean age = 17.4 years, SD = 8.0) were matched with 48 controls (mean age = 17.8 years, SD = 8.2). On average, the controls had 52-72 μm thicker ciliary muscles in the apical region at 0D than those with AI (p = 0.03 for both CMTMAX and CMT 0.75). Differences in thickness between the groups in other regions of the muscle were not statistically significant. After 8 weeks of accommodative/vergence therapy, the CMT increased by an average of 22-42 μm (p ≤ 0.04 for all), while AA increased by 7D (p < 0.001).

CONCLUSIONS

This study demonstrated significantly thinner apical ciliary muscle thickness in those with AI and that the ciliary muscle can thicken in response to increased workload. This may explain the mechanism for improvement in signs and symptoms with accommodative/vergence therapy.

Using evidence-based psychological approaches to accommodation anomalies

INTRODUCTION

Accommodation anomalies are frequently caused or exacerbated by psychological problems such as anxiety. Patients share many features with those with other anxiety based somatic symptoms such as stomach-ache, palpitations and headaches. They can be difficult to treat, and the ophthalmic literature rarely goes beyond diagnosis and ocular treatment. This study reports characteristics and outcomes of a short case series of patients with accommodation spasms and weaknesses assessed objectively, and outlines a psychological approach to treatment.

METHODS

23 patients (13 severe accommodative weakness or "paralysis," 10 accommodative spasm) aged between 8-30 years, were referred to our laboratory after diagnosis by their referring clinician and exclusion of pathology or drug-related causes. Their accommodation and convergence were assessed objectively with a laboratory photorefractive method, as well as by conventional orthoptic testing and dynamic retinoscopy. All interactions with the patients used an evidence-based psychological approach, to give them insight into how stress and anxiety can cause or exacerbate eye symptoms and help them to break a vicious cycle of anxiety and risk of deterioration.

RESULTS

83% were female and 57% had previously diagnosed anxiety or dyslexia (with many more acknowledging being "worriers"). Inconsistency of responses was the rule and all showed normal responses at some time during their visit. Responses were poorly related to the visual stimuli presented and objective responses often differed from subjective. Dissociation between convergence and accommodation was more common, compared to our large, previously reported, control groups. No participant had true paralysis of accommodation. Responses often improved dramatically within one session after discussion and explanation of the strong relationship between anxiety and accommodative anomalies. None have returned for further advice or treatment.

CONCLUSIONS

Our approach explicitly addresses psychological factors in causing, or worsening, accommodation (and co-existing convergence) anomalies. Many of these patients do not realize that a certain amount of blur is normal in everyday life. Ocular symptoms are often a sign of anxiety, not the primary problem. By recognizing this, patients can be helped to address the triggering issues and symptoms often subside or resolve spontaneously. Well-meaning professionals, offering only ocular treatments, can deflect attention away from the real cause and can unwittingly be making things worse.

Vergence/accommodative therapy for symptomatic convergence insufficiency in children: Time course of improvements in convergence function

PURPOSE

To evaluate the time course of improvements in clinical convergence measures for children with symptomatic convergence insufficiency treated with office-based vergence/accommodative therapy.

METHODS

We evaluated convergence measures from 205, 9- to 14-year-old children with symptomatic convergence insufficiency randomised to office-based vergence/accommodative therapy in the Convergence Insufficiency Treatment Trial - Attention and Reading Trial (CITT-ART). Near-point of convergence (NPC) and near-positive fusional vergence (PFV) were measured at baseline and after 4, 8, 12 and 16 weeks of therapy; mean change in NPC and PFV between these time points were compared using repeated measures analysis of variance. Rates of change in NPC and PFV from: (1) baseline to 4 weeks and (2) 4-16 weeks were calculated. For each time point, the proportion of participants to first meet the normal criterion for NPC (<6 cm), PFV blur (break if no blur; >15Δ and >2 times the exodeviation) and convergence composite (NPC and PFV both normal) were calculated.

RESULTS

The greatest change in NPC and PFV (7.6 cm and 12.7 Δ) and the fastest rate of improvement in NPC and PFV (1.9 cm/week and 3.2 Δ/week, respectively) were both found during the first 4 weeks of therapy, with both slowing over the subsequent 12 weeks. After 12 weeks of therapy, the NPC, PFV and convergence composite were normal in 93.2%, 91.7% and 87.8% of participants, respectively, and normalised with another 4 weeks of therapy in 4.4%, 2.0% and 4.4% of participants, respectively.

CONCLUSION

Although the greatest improvements in NPC and PFV occurred in the first 4 weeks of therapy, most participants had weekly improvements over the subsequent 12 weeks of treatment. While most children with convergence insufficiency obtained normal convergence following 12 weeks of therapy, an additional 4 weeks of vergence/accommodative therapy may be beneficial for some participants.

Virtual reality-based vision therapy versus OBVAT in the treatment of convergence insufficiency, accommodative dysfunction: a pilot randomized controlled trial

Background

Virtual reality is being increasingly applied in vision therapy. However, the differences in effectiveness, optimal treatment cycle, and prognosis between virtual reality-based vision therapy and traditional therapies remain unknown. The purpose of this study was to compare the effectiveness of virtual reality-based vision therapy and office-based vergence/accommodative therapy in young adults with convergence insufficiency or accommodative dysfunction.

Methods

The patients were randomly assigned to either the virtual reality-based vision therapy group or the office-based vergence/accommodative therapy group. The vision therapy lasted 12 weeks (1 h/week) in both groups. Binocular visual functions (vergence and accommodation) were measured and a subjective questionnaire-based assessment was performed at baseline and after 6 and 12 weeks of therapy.

Results

In total, 33 patients with convergence insufficiency and 30 with accommodative dysfunction completed the study. After 12 weeks of treatment for convergence insufficiency, the Convergence Insufficiency Symptom Survey score (F_2,31 = 13.704, P < 0.001), near point of convergence (F_2,31 = 21.774, P < 0.001), positive fusional vergence (F_2,31 = 71.766, P < 0.001), and near horizontal phoria (F_2,31 = 16.482, P < 0.001) improved significantly in both groups. Moreover, the monocular accommodative amplitude (F_2,25 = 22.154, P < 0.001) and monocular accommodative facility (F_2,25 = 86.164, P < 0.001) improved significantly in both groups after 12 weeks of treatment. A statistically significant difference was observed in monocular accommodative facility (F_1,25 = 8.140, P = 0.009) between the two groups, but not in other vergence and accommodative functions (0.098 < P < 0.687).

Conclusion

Virtual reality-based vision therapy significantly improved binocular vision functions and symptoms in patients with convergence insufficiency and accommodative dysfunction, thereby suggesting its effectiveness as a new optional or additional treatment for young adults with these conditions.

Trial registration

This study was registered at the Chinese Clinical Trials Registry on 16/04/2019 (identifier: ChiCTR1900022556).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02393-z.

Study of the Immediate Effects of Autostereoscopic 3D Visual Training on the Accommodative Functions of Myopes

Purpose

Stereoscopic viewing has an impact on ocular dynamics, but its effects on accommodative functions are not fully understood, especially for autostereoscopic viewing. This study aimed to investigate the changes in dynamic accommodative response, accommodative amplitude, and accommodative facility of myopes after autostereoscopic visual training.

Methods

We enrolled 46 adults (men = 22 and women = 24; age = 21.5 ± 2.5 [range = 18–25] years, spherical equivalent: −4.52 ± 1.89 [−8.88 to −1.75] diopters [D]) who visited the Eye & ENT Hospital of Fudan University. The study population was randomly divided into three-dimensional (3D) and two-dimensional (2D) viewing groups to watch an 11-minute training video displayed in 3D or 2D mode. Dynamic accommodative response, accommodative facility, and accommodative amplitude were measured before, during, and immediately after the training. Accommodative lag and the variability of accommodation were also analyzed. Visual fatigue was evaluated subjectively using a questionnaire.

Results

Accommodative lag decreased from 0.54 ± 0.29 D to 0.42 ± 0.32 D (P = 0.004), whereas accommodative facility increased from 10.83 ± 4.55 cycles per minute (cpm) to 13.15 ± 5.25 cpm (P < 0.001) in the 3D group. In the 2D group, there was no significant change in the accommodative lag (P = 0.163) or facility (P = 0.975), but a decrease in accommodative amplitude was observed (from 13.88 ± 3.17 D to 12.71 ± 2.23 D, P = 0.013). In the 3D group, the accommodative response changed with the simulated target distance. Visual fatigue was relatively mild in both groups.

Conclusions

The immediate impact of autostereoscopic training included a decrease in the accommodative lag and an increase in the accommodative facility. However, the long-term effects of autostereoscopic training require further exploration.

Does coexisting accommodative dysfunction impact clinical convergence measures, symptoms and treatment success for symptomatic convergence insufficiency in children?

PURPOSE

To determine whether coexisting accommodative dysfunction in children with symptomatic convergence insufficiency (CI) impacts presenting clinical convergence measures, symptoms and treatment success for CI.

METHODS

Secondary data analyses of monocular accommodative amplitude (AA; push-up method), monocular accommodative facility (AF; ±2.00 D lens flippers) and symptoms (CI Symptom Survey [CISS]) in children with symptomatic CI from the Convergence Insufficiency Treatment Trial (N = 218) and CITT-Attention and Reading Trial (N = 302) were conducted. Decreased AA was defined as more than 2D below the minimum expected amplitude for age (15 - ¼ age); those with AA < 5 D were excluded. Decreased AF was defined as <6 cycles per minute. Mean near point of convergence (NPC), near positive fusional vergence (PFV) and symptoms (CISS) were compared between those with and without accommodative dysfunction using analysis of variance and independent samples t-testing. Logistic regression was used to compare the effect of baseline accommodative function on treatment success [defined using a composite of improvements in: (1) clinical convergence measures and symptoms (NPC, PFV and CISS scores) or (2) solely convergence measures (NPC and PFV)].

RESULTS

Accommodative dysfunction was common in children with symptomatic CI (55% had decreased AA; 34% had decreased AF). NPC was significantly worse in those with decreased AA (mean difference = 6.1 cm; p < 0.001). Mean baseline CISS scores were slightly worse in children with coexisting accommodative dysfunction (decreased AA or AF) (30.2 points) than those with normal accommodation (26.9 points) (mean difference = 3.3 points; p < 0.001). Neither baseline accommodative function (p ≥ 0.12 for all) nor interaction of baseline accommodative function and treatment (p ≥ 0.50) were related to treatment success based on the two composite outcomes.

CONCLUSIONS

A coexisting accommodative dysfunction in children with symptomatic CI is associated with worse NPC, but it does not impact the severity of symptoms in a clinically meaningful way. Concurrent accommodative dysfunction does not impact treatment response for CI.

Investigation of the Relationship Between Subjective Symptoms of Visual Fatigue and Visual Functions

Purpose

To investigate whether the severity of symptoms of visual fatigue might be associated with clinical visual measures and basic visual functions, such as accommodation, vergence, and contrast sensitivity.

Methods

In this study, 104 students were recruited (25 males, 79 females, Age 23.4 ± 2.5) for this study. Those with high myopia, strabismus, anisometropia, eye disease or history of ophthalmological surgery were excluded. The included subjects completed a questionnaire that assesses the severity of visual fatigue. Then, binocular accommodative facility, vergence facility and contrast sensitivity using a quick contrast sensitivity function approach were measured in a random sequence. Next, the correlations between each symptom of visual fatigue in the questionnaire and accommodative facility, vergence facility and contrast sensitivity were examined.

Results

Factor analysis indicated that visual fatigue, as captured by the scores of a subset of the questionnaire items, could be strongly related to binocular accommodative facility and binocular contrast sensitivity, but not to vergence facility. We also found that binocular accommodative facility and contrast sensitivity at high spatial frequencies are related.

Conclusion

Our findings suggest that visual fatigue is related to the ability of human observers to encode visual details through their binocular vision.