Visual Fatigue and Accommodative Dynamics in Asymptomatic Individuals

A Novel Bluetooth-Based Automated Flipper for Measuring Accommodative Facility: a Comparison with Conventional Manual Flipper

Purpose

To evaluate the diagnostic accuracy of a Bluetooth-based automated flipper for measuring accommodative facility (AF) in children.

Design

A cross sectional study with crossover design.

Participants

Children aged 8 to 12 years were enrolled and randomly divided into 2 groups (A and B).

Methods

Initially, group A participants used the manual flipper to measure monocular (MAF) and binocular (BAF) AF, whereas participants in group B used the automated flipper. Subsequently, the groups underwent a crossover, exchanging the methods to measure AF. The diagnostic accuracy of the automated flipper was evaluated against gold standard, which defined inadequate AF as <7 cycles per minute (cpm) for MAF and <5 cpm for BAF, as measured with the manual flipper.

Main Outcome Measures

Accommodative facility measured using automated and manual flipper. Area under the receiver operating characteristic curve for automated flipper; sensitivity and specificity at the optimal cutoff (maximal Youden index).

Results

The average age of the 129 participants was 10.50 ± 1.42 years. The MAF and BAF values obtained using automated flipper were significantly correlated with those from the manual flipper (correlation coefficients of 0.819 and 0.813, respectively, both P < 0.001). The mean MAF and BAF measured with the automated flipper were 9.30 ± 2.30 cpm and 9.13 ± 2.34 cpm, respectively, significantly higher than the manual flipper's measurements (8.53 ± 2.16 cpm and 8.33 ± 2.22 cpm, respectively), even after adjusting for the learning effect associated with multiple measurements using analysis of variance for crossover design. The area under the curve for the automated flipper in diagnosing inadequate MAF and BAF was 0.911 (cutoff value = 9 cpm, sensitivity = 71.11%, specificity = 97.44%) and 0.920 (cutoff value = 7 cpm, sensitivity = 85.34%, specificity = 84.62%), respectively.

Conclusions

The automated flipper showed a strong correlation with the manual flipper, and demonstrated satisfactory sensitivity and specificity in diagnosing inadequate AF. It is recommended that the Bluetooth-based automated flipper be adopted as a novel tool to enhance the accuracy of AF testing in children.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Accommodative response and visual fatigue following a non-congruent visual task in non-asthenopic and asthenopic individuals

PURPOSE

Asthenopia is related to near vision activities or visual tasks that dissociate accommodation from vergence. Since the results of previous studies using objective measures to diagnose asthenopia are inconsistent, this study compared optometric tests and objective metrics of accommodation in non-asthenopic and asthenopic young adults before and after a visual fatigue task.

METHODS

The accommodative response was recorded objectively for 6 min at a 3.33 D accommodative demand using an autorefractor, before and after a 5-min non-congruent visual task. Accommodation was disassociated from vergence with a ±2.00 D accommodative flipper while reading at the same distance. Optometric tests and subjective evaluations of asthenopia were performed before and after the task. Twenty-six non-presbyopic adults (23.15 ± 2.56 years) were included and identified as asthenopic (n = 14) or non-asthenopic (n = 12) based on their score on the Computer Vision Syndrome Questionnaire.

RESULTS

A mixed ANOVA found no significant difference between the groups for objective (accommodative response) or subjective metrics (feeling of fatigue, optometric tests), although all participants reported greater visual fatigue after the task. A significant effect of time (before and after the non-congruent task) was identified for the overall sample for mean accommodative lag (+0.10 D, p = 0.01), subjective visual fatigue (+1.18, p < 0.01), negative relative accommodation (-0.20 D, p = 0.02) and near negative fusional reserve (blur: +2.46Δ, p < 0.01; break: +1.89Δ, p < 0.01; recovery: +3.34Δ, p = 0.02).

CONCLUSIONS

The task-induced asthenopia, measured both objectively and subjectively, was accompanied by a change in accommodative lag, greater visual fatigue and a decrease in negative relative accommodation. Conversely, near negative fusional reserves seem to adapt to the task. No significant differences were found between the two groups with respect to accommodative metrics (objective) or subjective and optometric tests.

Cognitive workload affects ocular accommodation and pupillary response

SIGNIFICANCE

Cognitive involvement in reading causes variations in the tonus of autonomic nerve system. The aim of this study was to examine the effect of short-term cognitive load on accommodation and pupils' absolute values and temporal variability in test persons performing three different types of tasks.

PURPOSE

We aimed to show how cognitive tasks of different type and difficulty level affect accommodation and pupil behavior during a short time interval.

METHODS

Participants (n = 58; mean age 16.4 years, SD = 0.56) performed reading from a 10-inch LCD screen placed at 40 cm distance. Three different types of tasks (numerical, textual, and the Stroop task), each at three different levels of cognitive load were introduced. Participants had 90 s to complete each task. Accommodative and pupillary responses were measured with videoretinoscope Power Refractor 3 at 50 Hz.

RESULTS

Pupil size was largest in the Stroop task (M = 5.20 mm, SD = 0.75 mm), followed by the numerical tasks (M = 5.02 mm, SD = 0.72 mm) and textual tasks (M = 4.78 mm, SD = 0.71 mm). Accommodative fluctuations - measured as accommodation SD - were largest in the textual tasks (M = 0.67 D, SD = 0.34 D), followed by the numerical tasks (M = 0.61 D, SD = 0.40 D) and the Stroop task (M = 0.52 D, SD = 0.21 D).

CONCLUSIONS

In our experiment, short-term cognitive load was associated with altered pupillary and accommodative response to near tasks. In conflicting tasks (Stroop) or in performing continuing calculations, the pupils were larger; in tasks requiring logical reasoning, the accommodative fluctuations were greater. These effects can potentially be associated with current near-point stress and myopia growth models.

Dynamics of the accommodative response and facility with dual-focus soft contact lenses for myopia control

OBJECTIVE

To assess the impact of using dual-focus soft contact lenses for myopia control on the dynamics of the accommodative response and facility.

METHODS

24 young adult myopes were fitted with dual-focus soft contact lenses for myopia control (MiSight®) and single-vision soft contact lenses (Proclear®). The WAM-5500 open-field autorefractor was used to measure the dynamics of the accommodative response (magnitude and variability) in binocular conditions, with accommodative data being gathered from the dominant eye, at three viewing distances (500 cm, 40 cm, and 20 cm) during 90 s. Also, the binocular accommodative facility was assessed with the WAM-5500 autorefractor. All participants performed the same experimental protocol with the dual-focus (MiSight) and single-vision (Proclear) soft contact lenses, with both experimental sessions being carried in two different days and following a counterbalanced order.

RESULTS

This study showed greater lags of accommodation with the MiSight than the Proclear lenses at near distances (40 cm: 1.27 ± 0.77 vs. 0.68 ± 0.37 D, corrected p-value = 0.002, Cohen-d = 0.90; and 20 cm: 1.47 ± 0.84 vs. 1.01 ± 0.52 D, corrected p-value = 0.007, Cohen-d = 0.75), whereas a higher variability of accommodation was observed with the dual-focus than the single-vision lenses at 500 cm (0.53 ± 0.11 vs. 0.23 ± 0.10 D), 40 cm (0.82 ± 0.31 vs. 0.68 ± 0.37 D), and 20 cm (1.50 ± 0.56 vs. 1.15 ± 0.39 D) (corrected p-value < 0.001 in all cases, and Cohen-ds = 0.67-2.33). Also, a worse quantitative (27.75 ± 8.79 vs. 34.29 ± 10.08 cycles per minute, p = 0.029, Cohen-d = 0.48) and qualitative (23.68 ± 7.12 vs. 28.43 ± 7.97 score, p = 0.039, Cohen-d = 0.45) performance was observed with the MiSight when compared to the Proclear lenses.

CONCLUSIONS

The use of dual-focus soft contact lenses for myopia control alters the dynamics of accommodative response and facility in the short-term. Although this optical design has demonstrated its effectiveness for myopia control, eye care specialists should be aware of the acute effects of these lenses on accommodation performance.

Less is more: optimal recording time for measuring the steady-state accommodative response

Clinical Relevance Background: Steady-state accommodation is frequently evaluated with open-field autorefractors; however there is no consensus regarding the optimal test duration. Our results allow us to standardise the procedure followed for the assessment of the steady-state accommodative response in clinical and laboratory settings and may be of great relevance in time-constrained situations.

BACKGROUND

The present study aims to determine the optimal recording time to assess the magnitude and variability of the accommodative response with a binocular open-field autorefractor.

METHODS

The steady-state accommodative response of 84 healthy undergraduate students was dynamically measured using the Grand Seiko WAM-5500 autorefractor at 500 cm, 40 cm and 20 cm for 90 s while participants maintained focus on a stationary target. We examined the reliability and level of agreement between four time intervals (the first 10-s, 30-s, 60-s and 90-s) at three accommodative demands (0.2D, 2.5D and 5D).

RESULTS

The magnitude of accommodation showed an excellent level of reliability (intraclass correlation coefficient [ICC]> 0.90) for the comparisons between the 90-s, 60-s and 30-s time intervals at the three viewing distances tested. However, when including the 10-s interval, there was a moderate reduction of the reliability indices and an increase of the mean difference between two time intervals (intra-class correlation [ICC] ranging from 0.89 to 0.97; and ESs ranging from 0.16 to 0.42). For the variability of accommodation, we observed an excellent reliability for the comparisons of the 90-s and 60-s measures at the three accommodative demands (ICC: 0.95-0.96), whereas for the rest of comparisons we observed from moderate to good levels of reliability.

CONCLUSION

Our data indicate that of 30-s and 60-s are enough to accurately assess the magnitude and variability of the accommodative response with the WAM-5500 autorefractor, respectively.

Association between ADHD and vision problems. A systematic review and meta-analysis

AIM

To conduct the first systematic review and meta-analysis assessing whether attention-deficit/hyperactivity disorder (ADHD) is associated with disorders of the eye, and/or altered measures of visual function.

METHOD

Based on a pre-registered protocol (PROSPERO: CRD42021256352), we searched PubMed, Web of Knowledge/Science, Ovid Medline, Embase and APA PsycINFO up to 16th November 2021, with no language/type of document restrictions. We included observational studies reporting at least one measure of vision in people of any age meeting DSM/ICD criteria for ADHD and in people without ADHD; or the prevalence of ADHD in people with and without vision disorders. Study quality was assessed with the Appraisal tool for Cross-Sectional Studies (AXIS). Random effects meta-analyses were used for data synthesis.

RESULTS

We included 42 studies in the narrative synthesis and 35 studies in the meta-analyses (3,250,905 participants). We found meta-analytic evidence of increased risk of astigmatism (OR = 1.79 [CI: 1.50, 2.14]), hyperopia and hypermetropia (OR = 1.79 [CI: 1.66, 1.94]), strabismus (OR = 1.93 [CI: 1.75, 2.12]), unspecified vision problems (OR = 1.94 [CI: 1.38, 2.73]) and reduced near point of convergence (OR = 5.02 [CI: 1.78, 14.11]); increased lag (Hedge's g = 0.63 [CI: 0.30, 0.96]) and variability (Hedge's g = 0.40 [CI: 0.17, 0.64]) of the accommodative response; and increased self-reported vision problems (Hedge's g = 0.63 [CI: 0.44, 0.82]) in people with ADHD compared to those without ADHD (with no significant heterogeneity). We also found meta-analytic evidence of no differences between people with and without ADHD on retinal nerve fiber layer thickness (Hedge's g = -0.19 [CI: -0.41, 0.02]) and refractive error (Hedge's g = 0.08 [CI: -0.26, 0.42]) (with no significant heterogeneity).

DISCUSSION

ADHD is associated with some self-reported and objectively ascertained functional vision problems, but not with structural alterations of the eye. Further studies should clarify the causal relationship, if any, between ADHD and problems of vision.

TRIAL REGISTRATION

PROSPERO registration: CRD42021256352.

Dynamics of the accommodative response after smoking cannabis

PURPOSE

Cannabis is the most widely consumed illicit drug worldwide. It has been suggested that cannabis could generate blurred vision during reading tasks. The goal of this study was to objectively assess the acute effects of smoking cannabis on the dynamics of ocular accommodation. The influence of other factors, including target distance and the direction of accommodation, as well as personal characteristics, were also analysed.

METHODS

Nineteen young people who were occasional cannabis users participated in the study (mean age 22.53 [3.12] years). Their usage profiles were evaluated by means of the Cannabis Use Disorders Identification Test-revised (CUDIT-r). The dynamics of the accommodative response were evaluated using an open-field auto refractor (Grand Seiko WAM-5500). The participants completed two different experimental sessions, one week apart, and in random order (baseline session and after smoking cannabis). During these sessions, the amplitude of the response (D), mean velocity (D/s), peak velocity (D/s), response time (s), accommodative lag (D) and accommodation variability (D) were measured.

RESULTS

The results indicated that cannabis use had a significant main effect on the mean accommodation/disaccommodation velocity (F_1,13  = 7.21; p = 0.02; η p 2  = 0.396). Cannabis consumption also interacted significantly with other factors. Response time showed a significant two-way interaction between condition × target distance (F_1,13  = 11.71; p = 0.005; η p 2  = 0.474) and condition × accommodation direction (F_1,13  = 8.71; p = 0.01; η p 2  = 0.401). For mean velocity, two-way interactions were found between condition × age (F_1,13  = 6.03; p = 0.03; η p 2  = 0.354), condition × CUDIT-r score (F_1,13  = 6.03; p = 0.03; η p 2  = 0.356) and condition × target distance (F_1,13  = 7.20; p = 0.02; η p 2  = 0.396).

CONCLUSIONS

These findings suggest that cannabis use can alter the accommodation process, although further studies should be carried out to explore the role of attention deficits. According to these results, certain daily activities that depend on an accurate accommodative function may be affected by cannabis use.

Capturing attention improves accommodation: An experimental study in children with ADHD using multiple object tracking

The present study was aimed at assessing the impact of manipulating the attentional load using a multiple object tracking (MOT) task on the dynamics of the accommodative response in children with attention deficit hyperactivity disorder (ADHD). The pupil size was recorded to assess the effectiveness of the experimental manipulation, and the role of ADHD medication was also explored. The accommodative and pupil dynamics (magnitude and variability) were monitored with an open-field autorefractometer (WAM-5500) in 41 children with ADHD (24 non-medicated and 17 medicated) and 21 non-ADHD controls, while they performed the MOT task with four different levels of complexity (i.e., tracking zero, one, two, or three targets). We found that increasing the attentional load caused a heightened accommodative response, showing a negative association between MOT complexity and accommodative lag in children with ADHD and non-ADHD controls. Complementarily, the pupil size increased as a function of task complexity, confirming a successful experimental manipulation. The stability of accommodation was insensitive to the attentional manipulation, but it differed between groups. Specifically, non-medicated children with ADHD exhibited a greater variability of accommodation in comparison to controls. Increasing the attentional load is associated with a reduction in the accommodative lag in children with ADHD and controls. Our findings show that the allocation of attention plays an important role in the dynamics of the accommodative response, which may be of relevance in the diagnosis and treatment of accommodative deficits in children with and without ADHD.

Effects of a blue-blocking screen filter on accommodative accuracy and visual discomfort

INTRODUCTION

The prescription of blue-blocking (B-B) filters for the management of visual symptoms and signs associated with the use of electronic devices is routinely performed by eye care specialists. However, the utility of B-B filters is a matter of debate and discussion by the scientific community due to the lack of evidence supporting their use. Here, we aimed to determine the effects of using B-B filters on the dynamics of the accommodative response and pupil size and perceived levels of visual discomfort, while performing a 30-min reading task at a close distance in subjects who routinely use electronic devices.

METHODS

Nineteen healthy young adults (22.0 ± 2.7 years) read two 30-min passages on a computer screen placed at 50 cm, either while using a commercially available B-B filter or without any filter on two different days. The magnitude and variability of both the accommodative response and pupil size were dynamically measured for 60 s using the WAM-5500 open field autorefractometer at 4-5, 9-10, 14-15, 19-20, 24-25, and 29-30 min into the trial. The perceived levels of visual discomfort were also obtained.

RESULTS

The lag and variability of accommodation were insensitive to the blue light level (p = 0.34 and 0.62, respectively). There was a time-on-task effect for the variability of accommodation, showing greater instability over time regardless of the blue light level. The use of the B-B filter was associated with improved reading speed (p = 0.02), with an increase of 16.5 words per minute. However, it was not associated with any significant change in pupil dynamics or the perceived levels of visual discomfort (p> 0.05 in both cases).

CONCLUSIONS

Our data showed that the use of a B-B filter had no effect on accommodative dynamics or visual symptomatology. Based on these findings, there is no support for the prescription of B-B filters to attenuate the visual symptoms and signs associated with the use of electronic devices in healthy young adults.

Functional Neuroanatomy of the Human Accommodation Response to an "E" Target Varying from -3 to -6 Diopters

Background: We aimed to identify the functional brain networks involved in the regulation of visual accommodation by contrasting the cortical functional areas evoked by foveal fixation to an "E" target, which were subservient to the accommodation responses to a -3/-6 diopter stimulus. Methods: Neural activity was assessed in healthy volunteers by changes in blood oxygen level-dependent (BOLD) signals measured with functional magnetic resonance imaging (fMRI). Twenty-five right-handed subjects viewed the "E" target presented in a hierarchical block design. They participated in two monocular tasks: (i) sustained foveal fixation upon an "E" target on a white background at 33 cm (-3.03D accommodative demand); and (ii) sustained fixation through an attached -3D concave lens (-6D accommodative demand) in front of the fixated eye; each condition cycled through a standard alternating 30-s eye open/30-s eye closed design to provide the BOLD contrast. The total sustained period was 480 s. Results: The contrast between the -3D and the rest condition revealed activation in the occipital lobe (Lingual gyrus, Cuneus, Calcarine_L, and Calcarine_R); cerebellum (Cerebellum_Crus1_L and Cerebellum_6_L); precentral lobe (Precentral_R); frontal lobe (Frontal_Inf_Oper_R and Frontal_Mid_R); and cingulate cortex (Cingulum_Ant_L). With the -3D concave lenses (-6D accommodative demand) in front of the fixated eye, the voxel size and peak intensity of activation in the occipital lobe and cerebellum were greater than with the -3D accommodative demand; emergent activated brain areas included the parietal lobe (bilateral precuneus gyrus and right supramarginal gyrus); the precentral lobe and cingulate cortex failed to reach the threshold in the -6D vs. rest contrast. In the -3D and -6D contrast comparison, the frontal lobe (Frontal_Sup_Medial_L) and parietal lobe (Precuneus_L and Precuneus_R) passed the significance threshold of cluster-level family-wise error (FWE) correction. The mean activation in the -3D and -6D contrast revealed an incremental summation of the activations than that found in the previous -3D vs. rest and -6D vs. rest comparisons. Conclusions: Neural circuits were selectively activated during the -3D/-6D accommodative response to blur cues. Cognitive-perceptual processing is involved in signal regulation of ocular accommodative functions.

Factors Affecting Recovery Trajectories in Pediatric Female Concussion

OBJECTIVE

Up to one-third of children with concussion have persistent postconcussion symptoms lasting beyond 4 weeks. Females have been shown to have prolonged concussion recovery compared with males. This study examined characteristics in pediatric athletes with concussion to investigate the underlying factors that may contribute to this difference and their relation to recovery trajectories in females compared with males.

DESIGN

A retrospective cohort study of pediatric patients with sports-related concussion (SRC).

SETTING

A subspecialty pediatric concussion program.

SUBJECTS

One hundred ninety-two records were reviewed, 75 females and 117 males, ages 7 to 18 years old.

ASSESSMENT OF RISK FACTORS

Sex of patient, time to presentation to specialty care after injury, presence of vision, and vestibular deficits on initial clinical examination.

MAIN OUTCOME MEASURES

The main outcome of interest was time to clinical recovery, defined by resolution of symptoms, recovery of physical examination deficits, including vision and vestibular examination, recovery of neurocognitive function, and return to school, exercise, and sport.

RESULTS

Pediatric females, on average, presented later to specialty care for evaluation after SRC than males. Females also took longer to recover on 5 markers of recovery: time to return to school without accommodations, time to return to noncontact exercise, time to return to full sport, time to recovery of neurocognitive function on computerized testing, and time to clinical recovery of vision and vestibular deficits on examination including smooth pursuits, saccades, gaze stability, near point of convergence, and balance. These sex-based differences in recovery disappeared when controlling for time to presentation to specialty care.

CONCLUSIONS

In this cohort of pediatric patients, ages 7 to 18 years old with SRC, females took longer to recover than males. Our results indicate, however, that a modifiable extrinsic factor, time to presentation to specialty care, may contribute to this difference in recovery between the sexes.

Stimulus Unpredictability in Time, Magnitude, and Direction on Accommodation

SIGNIFICANCE

The effect of predictability in changes of time, magnitude, and direction of the accommodation demand on the accommodation response latency and its magnitude are insignificant, which suggests that repetitive accommodative tasks such as the clinical accommodative facility test may not be influenced by potential anticipation effects.

PURPOSE

The purpose of this study was to investigate the effect of stimulus' time, magnitude, and direction predictability, as well as their interactions, on accommodation latency and response magnitude.

METHODS

Monocular accommodative response and latency were measured in 12 young subjects for nine different conditions where the stimulus accommodative demand changed several times in a steplike fashion for a period of 120 seconds. Each change in accommodative demand could have different time duration (i.e., 1, 2, or 3 seconds), magnitude (1, 2, or 3 diopters), and/or direction (i.e., accommodation or disaccommodation). All conditions were created permuting the factors of time, magnitude, and direction with two levels each: random and not random. The baseline condition was a step signal from 0 to 2 diopters persisting for 2 seconds in both accommodative demands. After each condition, subjects were asked to provide a score from 1 to 5 in their perceived predictability.

RESULTS

Friedman test conducted on the perceived predictability of each condition resulted in statistically significant differences between the nine conditions (χ = 56.57, P < .01). However, repeated-measures analysis of variance applied to latency and accommodative response magnitude did not show significant differences (P > .05). In addition, no correlation was found between the perceived predictability scores and both latency and accommodative response magnitudes between the most predictable and the most unpredictable conditions.

CONCLUSIONS

Subjects were able to perceptually notice whether the stimulus was predictable or not, although our results indicate no significant effect of stimuli predictability on either the accommodation latency or its magnitude.

Is 25Hz enough to accurately measure a dynamic change in the ocular accommodation?

BACKGROUND

Accommodation is often recorded at a low sampling rate using devices such as autorefractors that are designed to measure the static refractive error. It is therefore important to determine if that resolution is sufficient to accurately measure the dynamic properties of accommodation. The current study provides both theoretical and empirical evidence on the ideal sampling rate necessary to measure a dynamic response.

METHODS

Accommodative and disaccommodative step stimuli ranging from 1-3D (1D steps) were presented using a Badal optical system. Responses from 12 children (8-13 years) and 6 adults (20-35 years) were recorded using a dynamic photorefractor (DPR). Fast Fourier transformation was applied to the unsmoothed dynamic responses including position, velocity and acceleration. Also, velocity and acceleration main sequence (MS) characteristics were compared between three photorefractor conditions on 3 subjects.

RESULTS

The Nyquist sampling limit necessary to accurately estimate position, velocity and acceleration was at least 5, 10 and 70Hz, respectively. Peak velocity and acceleration were significantly underestimated at a lower rate (p<0.5). However, the slope of MS remained invariant with sampling rate (p>0.5).

CONCLUSION

Contrary to the previous findings, a dynamic accommodative response exhibited frequencies larger than 10Hz. Stimulus direction and amplitude had no influence on the frequencies present in the dynamic response. Peak velocity and acceleration can be significantly underestimated when sampled at a lower rate. Taken as a whole, low sampling rate instruments can accurately estimate static accommodation, however, caution needs to be exercised when using them for dynamic accommodation.

Random Changes of Accommodation Stimuli: An Automated Extension of the Flippers Accommodative Facility Test

PURPOSE

To study the accommodative dynamics for predictable and unpredictable stimuli using manual and automated accommodative facility tests Materials and Methods: Seventeen young healthy subjects were tested monocularly in two consecutive sessions, using five different conditions. Two conditions replicated the conventional monocular accommodative facility tests for far and near distances, performed with manually held flippers. The other three conditions were automated and conducted using an electro-optical system and open-field autorefractor. Two of the three automated conditions replicated the predictable manual accommodative facility tests. The last automated condition was a hybrid approach using a novel method whereby far and near-accommodative-facility tests were randomly integrated into a single test of four unpredictable accommodative demands.

RESULTS

The within-subject standard deviations for far- and near-distance-accommodative reversals were (±1,±1) cycles per minute (cpm) for the manual flipper accommodative facility conditions and (±3, ±4) cpm for the automated conditions. The 95% limits of agreement between the manual and the automated conditions for far and near distances were poor: (-18, 12) and (-15, 3). During the hybrid unpredictable condition, the response time and accommodative response parameters were significantly (p < 0.05) larger for accommodation than disaccommodation responses for high accommodative demands only. The response times during the transitions 0.17/2.17 D and 0.50/4.50 D appeared to be indistinguishable between the hybrid unpredictable and the conventional predictable automated tests.

CONCLUSIONS

The automated accommodative facility test does not agree with the manual flipper test results. Operator delays in flipping the lens may account for these differences. This novel test, using unpredictable stimuli, provides a more comprehensive examination of accommodative dynamics than conventional manual accommodative facility tests. Unexpectedly, the unpredictability of the stimulus did not to affect accommodation dynamics. Further studies are needed to evaluate the sensitivity of this novel hybrid technique on individuals with accommodative anomalies.

Vestibular Deficits following Youth Concussion

OBJECTIVE

To characterize the prevalence and recovery of pediatric patients with concussion who manifest clinical vestibular deficits and to describe the correlation of these deficits with neurocognitive function, based on computerized neurocognitive testing, in a sample of pediatric patients with concussion.

METHODS

This was a retrospective cohort study of patients ages 5-18 years with concussion referred to a tertiary pediatric hospital-affiliated sports medicine clinic from July 1, 2010 to December 31, 2011. A random sample of all eligible patient visits was obtained, and all related visits for those patients were reviewed.

RESULTS

A total of 247 patients were chosen from 3740 eligible visits for detailed review and abstraction; 81% showed a vestibular abnormality on initial clinical examination. Those patients with vestibular signs on the initial examination took a significantly longer time to return to school (median 59 days vs 6 days, P=.001) or to be fully cleared (median 106 days vs 29 days, P=.001). They additionally scored more poorly on initial computerized neurocognitive testing, and it took longer for them to recover from neurocognitive deficits. Those patients with 3 or more previous concussions had a greater prevalence of vestibular deficits, and it took longer for those deficits to resolve.

CONCLUSION

Vestibular deficits in children and adolescents with a history of concussion are highly prevalent. These deficits appear to be associated with extended recovery times and poorer performance on neurocognitive testing. Further studies evaluating the effectiveness of vestibular therapy on improving such deficits are warranted.

Characteristics of prolonged concussion recovery in a pediatric subspecialty referral population

OBJECTIVE

To identify pre-existing characteristics associated with prolonged recovery from concussion in a sample of patients referred to a pediatric sports medicine clinic.

STUDY DESIGN

This was a retrospective, exploratory cohort study of 247 patients age 5-18 years with concussion referred to a tertiary pediatric hospital-affiliated sports medicine clinic from July 1, 2010, through December 31, 2011. A random sample of all eligible patient visits (3740) was chosen for further review and abstraction. Statistical comparisons between subsets of patients were conducted using exact χ(2) tests, logistic regression, quantile regression, and Kaplan-Meier survival curves.

RESULTS

The median time until returning to school part-time was 12 days (IQR 6-21); until returning to school full-time without accommodations was 35 days (IQR 11-105); until becoming symptom-free was 64 days (IQR 18-119); and until being fully cleared to return to sports was 75 days (IQR 30-153). Furthermore, 73% of all patients were symptomatic for >4 weeks, 73% were prescribed some form of school accommodation, and 61% reported a decline in grades. Characteristics associated with a prolonged recovery included a history of depression or anxiety; an initial complaint of dizziness; abnormal convergence or symptom provocation following oculomotor examination on physical examination; and history of prior concussion.

CONCLUSIONS

Pediatric and adolescent patients with concussion may experience cognitive and emotional morbidity that can last for several months following injury. Clinicians should consider specific pre-existing characteristics and presenting symptoms that may be associated with a more complicated recovery for concussion patients.