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Cerebrovascular reactivity (CVR) is routinely measured as a predictor of stroke in people with a high risk of ischemic attack. Neuroimaging techniques such as emission tomography, magnetic resonance imaging, and transcranial doppler are frequently used to measure CVR even though each technique has its limitations. Functional near-infrared spectroscopy (fNIRS), also based on the principle of neurovascular coupling, is relatively inexpensive, portable, and allows for the quantification of oxy- and deoxy-hemoglobin concentration changes at a high temporal resolution. This study examines the relationship between age and CVR using fNIRS in 45 young healthy adult participants aged 18–41 years (6 females, 26.64 ± 5.49 years) performing a simple breath holding task. Eighteen of the 45 participants were scanned again after a week to evaluate the feasibility of fNIRS in reliably measuring CVR. Results indicate (a) a negative relationship between age and hemodynamic measures of breath holding task in the sensorimotor cortex of 45 individuals and (b) widespread positive coactivation within medial sensorimotor regions and between medial sensorimotor regions with supplementary motor area and prefrontal cortex during breath holding with increasing age. The intraclass correlation coefficient (ICC) indicated only a low to fair/good reliability of the breath hold hemodynamic measures from sensorimotor and prefrontal cortices. However, the average hemodynamic response to breath holding from the two sessions were found to be temporally and spatially in correspondence. Future improvements in the sensitivity and reliability of fNIRS metrics could facilitate fNIRS-based assessment of cerebrovascular function as a potential clinical tool.

Purpose The purpose of this study was to compare changes in phoria adaptation between young adult binocularly normal controls (BNCs) and participants with symptomatic convergence insufficiency (CI), who were randomized to either office-based vergence accommodative therapy (OBVAT) or office-based placebo therapy (OBPT). Methods In the double-masked randomized clinical trial, 50 BNC and 50 CI participants were randomized to the following therapeutic interventions: OBVAT or OBPT with home reinforcement for 12 one-hour office sessions. A 6∆ base-out and 6∆ base-in phoria adaptation experiment at near (40 cm) was conducted using the flashed Maddox rod technique at baseline and at outcome. Measurements included the rate and the magnitude of phoria adaptation. Results At baseline, BNC and CI participants had significantly different rates and magnitudes of base-in and base-out phoria adaptation (P < 0.001). When comparing the outcome to baseline measurements, significant main effect differences in longitudinal measurements were observed for the magnitude and the rate of phoria adaptation for both base-out and base-in experiments (P < 0.05). For the magnitude and rate of phoria adaptation, post hoc analyses using paired t-tests revealed that the CI group administered the OBVAT intervention exhibited a significant increase in the magnitude and rate of phoria adaptation compared to baseline for both base-in and base-out phoria adaptation (P < 0.01) but not for those administered OBPT. Conclusions Phoria adaptation is significantly different at baseline between those with normal binocular vision and symptomatic CI participants. OBVAT significantly improves the rate and magnitude of both base-out and base-in phoria adaptation at near compared to OBPT. Results have clinical implications for new therapeutic interventions.

PURPOSE: To describe the design and methodology of the Convergence Insufficiency Neuro-mechanism in Adult Population Study (CINAPS), the first randomized clinical trial (RCT) studying young adults with symptomatic convergence insufficiency (CI) using a combination of traditional clinical tests, objective eye movement recordings, and functional brain activities as outcome measures. METHODS: In this double-masked RCT, binocularly normal controls (BNC) (N=50) and CI patients (N=50) are randomized into office-based vergence/accommodative therapy (OBVAT) or office-based placebo therapy (OBPT). Outcome measures included clinical signs and symptoms, phoria adaptation, forced fixation disparity curves, binocular rivalry, vergence and saccadic objective eye movements, and task-induced functional brain activities. This study is registered on ClinicalTrials.gov . RESULTS: No significant baseline differences are observed between the BNC (p>0.4) or CI (p>0.3) participants assigned to OBVAT or OBPT for age, near point of convergence (NPC), positive fusional vergence (PFV), phoria at distance and near, amplitude of accommodation, or the Convergence Insufficiency Symptom Survey (CISS). Significant differences are observed between the CI and BNC cohorts at baseline measurements for NPC, PFV, difference in phoria from far to near, amplitude of accommodation, and CISS (p

The Vergence Endurance Test (VET), a quantitative and objective eye movement assessment, was utilized to differentiate control from concussed subjects. Nine symptomatic concussed (2 male; 30.8 ± 11 years) and 9 asymptomatic control (6 male; 25.1 ± 1.4 years) subjects participated in the VET. Symmetrical disparity vergence step targets were presented with and without visual distractors. A masked data analyst measured vergence latency, peak velocity, response amplitude, settling time, and the percentage of trials which contained blinks. A Binocular Precision Index (BPI) and a Binocular Accuracy Index (BAI) were calculated to quantify the changes that occur in the vergence parameters over the duration of the VET. Convergence and divergence peak velocity, divergence response amplitude, the percentage of trials that contained blinks during the transient portion of the response, and the BAI were significantly (p

SIGNIFICANCE This study establishes normative data and a testing procedure for the oculomotor assessment tool. The oculomotor assessment tool standardizes visual targets for the Vestibular/OculoMotor Screening assessment and provides additional metrics that may aid in the differentiation between those with normal and those with abnormal oculomotor function potentially caused by a concussion. PURPOSE This study aimed to assess the oculomotor endurance of healthy participants with no self-reported history of concussions using the oculomotor assessment tool. METHODS Healthy participants (n = 376, average age of 20.4 years, range of 11 to 34 years, with no self-reported history of concussions) were recruited to perform the following three tasks for 60 seconds each: (1) horizontal saccades, (2) vertical saccades, and (3) vergence jumps. The participants were instructed to alternate visual fixation between two targets for each of the tasks as fast as they could without overshooting or undershooting the visual target. The differences in the number of eye movements between the initial and latter 30 seconds of the 1-minute test were analyzed. RESULTS A statistical difference (P < .001) was observed in the number of eye movements for all three tasks (horizontal saccades [70 ± 15 for initial 30 seconds, 63 ± 13 for latter 30 seconds], vertical saccades [68 ± 14, 63 ± 13], and vergence jumps [43 ± 11, 39 ± 10]) between the initial and latter 30 seconds. No significant differences were identified in the number of eye movements or the change in eye movements between the initial and latter 30 seconds based on sex. CONCLUSIONS These results establish a normative database for various eye movements. These data could potentially be used to compare different patient populations who have binocular endurance dysfunctions potentially due to traumatic brain injury, such as patients with concussion(s).

Background: Traumatic brain injury (TBI)-induced attention deficits are among the most common long-term cognitive consequences in children. Most of the existing studies attempting to understand the neuropathological underpinnings of cognitive and behavioral impairments in TBI have utilized heterogeneous samples and resulted in inconsistent findings. The current research proposed to investigate topological properties of the structural brain network in children with TBI and their relationship with post-TBI attention problems in a more homogeneous subgroup of children who had severe post-TBI attention deficits (TBI-A). Materials and Methods: A total of 31 children with TBI-A and 35 group-matched controls were involved in the study. Diffusion tensor imaging-based probabilistic tractography and graph theoretical techniques were used to construct the structural brain network in each subject. Network topological properties were calculated in both global level and regional (nodal) level. Between-group comparisons among the topological network measures and analyses for searching brain-behavioral were all corrected for multiple comparisons using Bonferroni method. Results: Compared with controls, the TBI-A group showed significantly higher nodal local efficiency and nodal clustering coefficient in left inferior frontal gyrus and right transverse temporal gyrus, whereas significantly lower nodal clustering coefficient in left supramarginal gyrus and lower nodal local efficiency in left parahippocampal gyrus. The temporal lobe topological alterations were significantly associated with the post-TBI inattentive and hyperactive symptoms in the TBI-A group. Conclusion: The results suggest that TBI-related structural re-modularity in the white matter subnetworks associated with temporal lobe may play a critical role in the onset of severe post-TBI attention deficits in children. These findings provide valuable input for understanding the neurobiological substrates of post-TBI attention deficits, and have the potential to serve as quantitatively measurable criteria guiding the development of more timely and tailored strategies for diagnoses and treatments to the affected individuals. IMPACT STATEMENT: This study provides a new insight into the neurobiological substrates associated with post-traumatic brain injury attention deficits (TBI-A) in children, by evaluating topological alterations of the structural brain network. The results demonstrated that relative to group-matched controls, the children with TBI-A had significantly altered nodal local efficiency and nodal clustering coefficient in temporal lobe, which strongly linked to elevated inattentive and hyperactive symptoms in the TBI-A group. These findings suggested that white matter structural re-modularity in subnetworks associated with temporal lobe may serve as quantitatively measurable biomarkers for early prediction and diagnosis of post-TBI attention deficits in children.

Convergence insufficiency (CI) is the most common binocular vision problem, associated with blurred/double vision, headaches, and sore eyes that are exacerbated when doing prolonged near work, such as reading. The Convergence Insufficiency Neuro-mechanism Adult Population Study (NCT03593031) investigates the mechanistic neural differences between 50 binocularly normal controls (BNC) and 50 symptomatic CI participants by examining the fast and slow fusional disparity vergence systems. The fast fusional system is preprogrammed and is assessed with convergence peak velocity. The slow fusional system optimizes vergence effort and is assessed by measuring the phoria adaptation magnitude and rate. For the fast fusional system, significant differences are observed between the BNC and CI groups for convergence peak velocity, final position amplitude, and functional imaging activity within the secondary visual cortex, right cuneus, and oculomotor vermis. For the slow fusional system, the phoria adaptation magnitude and rate, and the medial cuneus functional activity, are significantly different between the groups. Significant correlations are observed between vergence peak velocity and right cuneus functional activity (p = 0.002) and the rate of phoria adaptation and medial cuneus functional activity (p = 0.02). These results map the brain-behavior of vergence. Future therapeutic interventions may consider implementing procedures that increase cuneus activity for this debilitating disorder.

Deficits of disparity divergence found with objective eye movement recordings may not be apparent with standard clinical measures of negative fusional vergence (NFV) in children with symptomatic convergence insufficiency.This study aimed to determine whether NFV is normal in untreated children with symptomatic convergence insufficiency and whether NFV improves after vergence/accommodative therapy.This secondary analysis of NFV measures before and after office-based vergence/accommodative therapy reports changes in (1) objective eye movement recording responses to 4° disparity divergence step stimuli from 12 children with symptomatic convergence insufficiency compared with 10 children with normal binocular vision (NBV) and (2) clinical NFV measures in 580 children successfully treated in three Convergence Insufficiency Treatment Trial studies.At baseline, the Convergence Insufficiency Treatment Trial cohort's mean NFV break (14.6 ± 4.8Δ) and recovery (10.6 ± 4.2Δ) values were significantly greater (P.001) than normative values. The post-therapy mean improvements for blur, break, and recovery of 5.2, 7.2, and 1.3Δ, respectively, were statistically significant (P.0001). Mean pre-therapy responses to 4° disparity divergence step stimuli were worse in the convergence insufficiency group compared with the NBV group for peak velocity (P.001), time to peak velocity (P = .01), and response amplitude (P.001). After therapy, the convergence insufficiency group showed statistically significant improvements in mean peak velocity (11.63°/s; 95% confidence interval [CI], 6.6 to 16.62°/s), time to peak velocity (-0.12 seconds; 95% CI, -0.19 to -0.05 seconds), and response amplitude (1.47°; 95% CI, 0.83 to 2.11°), with measures no longer statistically different from the NBV cohort (P.05).Despite clinical NFV measurements that seem greater than normal, children with symptomatic convergence insufficiency may have deficient NFV when measured with objective eye movement recordings. Both objective and clinical measures of NFV can be improved with vergence/accommodative therapy.

Traumatic brain injury (TBI)-induced attention deficits are among the most common long-term cognitive consequences in children. Most of the existing studies attenpting to understand the neuropathological underpinnings of cognitive and behavioral impairments in TBI have utilized heterogeneous samples and resulted in inconsistent findings. The current research proposed to investigate topological properties of the structural brain network in children with TBI and their associations with TBI-induced attention problems in a more homogeneous subgroup of children who had severe post-TBI attention deficits (TBI-A).A total of 31 children with TBI-A and 35 group-matched controls were involved in the study. Diffusion tensor imaging-based probabilistic tractography and graph theoretical techniques were used to construct the structural brain network in each subject. Network topological properties were calculated in both global level and regional (nodal) level. Between-group comparisons among the topological network measures and analyses for searching brain-behavioral associations were all corrected for multiple comparisons using Bonferroni method.Compare to controls, the TBI-A group showed significantly higher nodal local efficiency and nodal clustering coefficient in left inferior frontal gyrus and right transverse temporal gyrus, while significantly lower nodal clustering coefficient in left supramarginal gyrus as well as lower nodal local efficiency in left parahippocampal gyrus. The temporal lobe topological alterations were significantly associated with the post-TBI inattentive and hyperactive symptoms in the TBI-A group.The results suggest that TBI-related structural re-modularity in the WM subnetworks associated with temporal lobe may play a critical role in the onset of severe post-TBI attention deficits in children. These findings provide valuable input for understanding the neurobiological substrates of TBI-A, and have the potential to serve as a biomarker guiding the development of more timely and tailored strategies for diagnoses and treatments to the affected individuals.

Significance This first report of the use of objective measures of disparity vergence as outcome measures for symptomatic convergence insufficiency in children provides additional information that is not accessible with clinical tests. The study results also demonstrate that objective measures of vergence could be used in future randomized clinical trials of binocular vision disorders with children. Purpose This study was designed to evaluate changes in objective measures of disparity vergence after office-based vergence/accommodative therapy (OBVAT) for convergence insufficiency in children 12 to 17 years old. Methods In this prospective trial, we recruited 10 participants with normal binocular vision and 12 with convergence insufficiency. All participants with convergence insufficiency were treated with 12 weeks of OBVAT. The primary outcome measure was average peak velocity for 4° symmetrical convergence steps. Other objective outcome measures of disparity vergence included time to peak velocity, latency, and accuracy. Changes in clinical measures (near point of convergence, positive fusional vergence at near) and symptoms were evaluated. Results There was a statistically significant increase in peak velocity and more accurate response amplitude to 4° symmetrical convergence step stimuli after OBVAT compared with baseline measurements. Near point of convergence, positive fusional vergence, and symptoms also statistically significantly improved after OBVAT. Ten of the 12 participants met clinical success criteria. Conclusions In this prospective study on the treatment of symptomatic convergence insufficiency in children in which both clinical and objective eye movement measurements were used to evaluate the results of treatment, significant changes were found in symptoms and both clinical and objective measures of disparity vergence after completion of OBVAT in children with symptomatic convergence insufficiency.

Attention deficit/hyperactivity disorder (ADHD) is a highly prevalent and impairing neurodevelopmental disorder that persists into adulthood in a sizeable portion of afflicted children. The persistence of ADHD elevates the risk for adverse outcomes that result in substantial individual and societal burden. The objective of this study is to assess neurobiological substrates associated with variability of clinical outcomes in childhood ADHD, which has considerable value for the development of novel interventions that target mechanisms associated with recovery. A total of 36 young adults who were diagnosed with ADHD combined-type during childhood and 33 group-matched controls were involved in the study. Adults with childhood ADHD were further divided into 17 persisters and 19 remitters based on DSM-5 criteria. Functional magnetic resonance imaging data during a cue-evoked attention task were collected from each subject. The cue-evoked attention processing network was constructed using graph theoretic techniques. Network properties, including global-, local-, and nodal-efficiency, and network hubs were computed. Group comparisons of the network properties were conducted. Significantly lower nodal efficiency in right inferior frontal gyrus and reduced left side frontal-parietal functional interactions were observed in both remitters and persisters relative to the controls. The ADHD persisters showed a unique pattern of significantly lower nodal efficiency in right middle frontal gyrus (MFG) and hyper-interactions between bilateral MFG. This study suggests that right MFG functional impairments may relate to inactive fronto-parietal functional interactions for sensory and cognitive information processing and symptom persistence in young adults with childhood ADHD.

People develop presbyopia as part of the normal aging process. Most presbyopes adapt to progressive additive lens (PALs), while others do not. This investigation sought to determine whether the ability to modify disparity vergence or phoria was correlated to PALs adaptation. In experiment 1, a double-step paradigm quantified the ability to modify convergence responses in sixteen presbyopes. In experiment 2, thirty-one incipient presbyopes participated in a 5-minute sustained fixation task to evoke phoria adaptation where the magnitude and rate of phoria adaptation were measured. Then, the experiment was repeated after wearing PALs for one month. Linear regression analyses were conducted between the following parameters: near point of convergence, positive fusional vergence at near, vergence facility, net change in the magnitude of phoria adaptation, and the rate of phoria adaptation. The ability to change convergence average peak velocity was significantly greater (p p

Office-Based Vergence/Accommodative Therapy (OBVAT) is an effective treatment for convergence insufficiency (CI) and remediates symptoms in about 75% of patients. Hence, the study of CI patients can serve as a systems-level model to understand the neural mechanisms evoked from rehabilitation. Symptomatic young adult CI patients (N=25) participated in 12 hours of OBVAT and were compared to 25 binocularly normal controls (BNC) using unpaired t-tests. CI patients have significantly lower near point of convergence and positive fusional vergence and were more symptomatic compared to BNC (p; 0.0001). Using paired t-tests, significant differences (p; 0.0001) were observed between CI patients' baseline and post-OBVAT measurements where the near point of convergence decreased, positive fusional vergence increased, and the results from the Convergence Insufficiency Symptom Survey (CISS) decreased. Using paired t-tests, the mean beta weights of the functional activity significantly increased for the frontal eye fields (p; 0.01) and the oculomotor vermis (p; 0.05) for CI patients post-OBVAT compared to baseline measurements. These data demonstrate that OBVAT increases functional activity within the brain and improves clinical function and visual symptoms in CI patients.

This study investigates the underlying physiological mechanisms that may lead to improved outcomes for symptomatic convergence insufficiency (CI) patients after 12 weeks of office-based vergence/accommodation therapy (OBVAT) by evaluating the change in the main sequence of vergence and saccadic eye movements. In this prospective trial, 12 participants with symptomatic CI were recruited and treated with 12 weeks of OBVAT. Outcome measures included the objective assessment of the following: peak velocity, time to peak velocity, latency, response amplitude, and clinical changes in the near point of convergence (NPC), positive fusional vergence (PFV) and symptoms via the Convergence Insufficiency Symptom Survey (CISS). Ten of the twelve participants (83%) were categorized as “successful” and two were “improved” based on pre-determined published criteria (CISS, NPC, PFV). There were statistically significant changes in peak velocity, time to peak velocity, and response amplitude for both 4° and 6° symmetrical convergence and divergence eye movements. There was a significant change in the main sequence ratio for convergence post-OBVAT compared to baseline measurements (P=0.007) but not for divergence or saccadic responses. Phasic/step vergence movements adjust the underlying neural control of convergence and are critical within a vision therapy program for CI patients.

Highlights • Features of nodal efficiency in right IFG, right MFG-IPL functional connectivity, and right amygdala volume for discrimination between ADHD probands and controls. • Higher nodal efficiency of right MFG greatly contributed to symptom remission. • Higher right MFG-IPL functional connectivity strongly linked to symptom persistence. • ELT-based classifiers were superior to the basic machine learning classifiers. • ELT may have the potential to identify more reliable neurobiological markers for neurodevelopmental disorder., Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent and heterogeneous neurodevelopmental disorder, which is diagnosed using subjective symptom reports. Machine learning classifiers have been utilized to assist in the development of neuroimaging-based biomarkers for objective diagnosis of ADHD. However, existing basic model-based studies in ADHD report suboptimal classification performances and inconclusive results, mainly due to the limited flexibility for each type of basic classifier to appropriately handle multi-dimensional source features with varying properties. This study applied ensemble learning techniques (ELTs), a meta-algorithm that combine several basic machine learning models into one predictive model in order to decrease variance, bias, or improve predictions, in multimodal neuroimaging data collected from 72 young adults, including 36 probands (18 remitters and 18 persisters of childhood ADHD) and 36 group-matched controls. All currently available optimization strategies for ELTs (i.e., voting, bagging, boosting and stacking techniques) were tested in a pool of semifinal classification results generated by seven basic classifiers. The high-dimensional neuroimaging features for classification included regional cortical gray matter (GM) thickness and surface area, GM volume of subcortical structures, volume and fractional anisotropy of major white matter fiber tracts, pair-wise regional connectivity and global/nodal topological properties of the functional brain network for cue-evoked attention process. As a result, the bagging-based ELT with the base model of support vector machine achieved the best results, with significant improvement of the area under the receiver of operating characteristic curve (0.89 for ADHD vs. controls and 0.9 for ADHD persisters vs. remitters). Features of nodal efficiency in right inferior frontal gyrus, right middle frontal (MFG)-inferior parietal (IPL) functional connectivity, and right amygdala volume significantly contributed to accurate discrimination between ADHD probands and controls; higher nodal efficiency of right MFG greatly contributed to inattentive and hyperactive/impulsive symptom remission, while higher right MFG-IPL functional connectivity strongly linked to symptom persistence in adults with childhood ADHD. Considering their improved robustness than the commonly implemented basic classifiers, findings suggest that ELTs may have the potential to identify more reliable neurobiological markers for neurodevelopmental disorders.

Background: Concussions are one of the most common head injuries acquired within the pediatric population. While sport-related concussions are well documented, concussions within other aspects of a child&rsquo, s life are not as well researched. The purpose of this study is to examine the incidence of a large pediatric concussion population in a broad range of daily activities. Methods: Patients&rsquo, gender and nature of injury were extracted from 1408 medical records of patients who were diagnosed with a concussion at Saint Peter&rsquo, s Sports Medicine Institute. Statistical analyses were conducted for activities and environmental settings using chi-squared tests. Results: Concussions were most prevalent in organized sports (53.3%), followed by injuries within the following settings: school (16.5%), recreational (6.7%), motor vehicle collisions (6.6%), home (5.5%), and other (11.3%). Specifically, soccer (12.9%), school physical education (PE) class (10.6%), and football (9.8%) subcategories recorded the most incidences of concussion. For the PE class cohort (n = 149), significantly more females were diagnosed with a concussion compared to males (p &lt, 0.001). Conclusions: PE-related concussions had the second highest incidence rate after organized sports. A significant gender difference was observed in PE class. Awareness about concussions and methods to reduce the risk of concussion is suggested for PE classes.

Aims This study aimed at understanding the neurobiological mechanisms associated with inattention induced by traumatic brain injury (TBI). To eliminate the potential confounding caused by the heterogeneity of TBI, we focused on young adults postsports-related concussion (SRC). Methods Functional near-infrared spectroscopy (fNIRS) data were collected from 27 young adults post-SRC and 27 group-matched normal controls (NCs), while performing a visual sustained attention task. Task responsive cortical activation maps and pairwise functional connectivity among six regions of interest were constructed for each subject. Correlations among the brain imaging measures and clinical measures of attention were calculated in each group. Results Compared to the NCs, the SRC group showed significantly increased brain activation in left middle frontal gyrus (MFG) and increased functional connectivity between right inferior occipital cortex (IOC) bilateral calcarine gyri (CG). The left MFG activation magnitude was significantly negatively correlated with the hyperactive/impulsive symptom severity measure in the NCs, but not in the patients. The right hemisphere CG-IOC functional connectivity showed a significant positive correlation with the hyperactive/impulsive symptom severity measure in patients, but not in NCs. Conclusion The current data suggest that abnormal left MFG activation and hyper-communications between right IOC and bilateral CG during visual attention processing may significantly contribute to behavioral manifestations of attention deficits in patients with TBI.

This study assessed the prevalence of convergence insufficiency (CI) with and without simultaneous vision dysfunctions within the traumatic brain injury (TBI) sample population because although CI is commonly reported with TBI, the prevalence of concurrent visual dysfunctions with CI in TBI is unknown.A retrospective analysis of 557 medical records from TBI civilian patients was conducted. Patients were all evaluated by a single optometrist. Visual acuity, oculomotor function, binocular vision function, accommodation, visual fields, ocular health, and vestibular function were assessed. Statistical comparisons between the CI and non-CI, as well as inpatient and outpatient subgroups, were conducted using χ and Z tests.Approximately 9% of the TBI sample had CI without the following simultaneous diagnoses: saccade or pursuit dysfunction; third, fourth, or sixth cranial nerve palsy; visual field deficit; visual spatial inattention/neglect; vestibular dysfunction; or nystagmus. Photophobia with CI was observed in 16.3% (21 of 130), and vestibular dysfunction with CI was observed in 18.5% (24 of 130) of the CI subgroup. Convergence insufficiency and cranial nerve palsies were common and yielded prevalence rates of 23.3% (130 of 557) and 26.9% (150 of 557), respectively, within the TBI sample. Accommodative dysfunction was common within the nonpresbyopic TBI sample, with a prevalence of 24.4% (76 of 314). Visual field deficits or unilateral visual spatial inattention/neglect was observed within 29.6% (80 of 270) of the TBI inpatient subgroup and was significantly more prevalent compared with that of the outpatient subgroup (p0.001). Most TBI patients had visual acuities of 20/60 or better in the TBI sample (85%; 473 of 557).Convergence insufficiency without simultaneous visual or vestibular dysfunctions was observed in about 9% of the visually symptomatic TBI civilian population studied. A thorough visual and vestibular examination is recommended for all TBI patients.

Purpose: This study examined the relationship between the near dissociated phoria and disparity vergence eye movements. Convergence insufficiency (CI) patients before vergence therapy were compared to: (1) the same patients after vergence therapy; and (2) binocularly normal controls (BNC). Methods: Sixteen subjects were studied—twelve BNC and four with CI. Measurements from the CI subjects were obtained before and after 18 h of vergence eye movement therapy. The near dissociated phoria was measured using the flashed Maddox rod technique. Vergence responses were stimulated from 4° symmetrical disparity vergence step stimuli. The peak velocity of the vergence response and the magnitude of the fusion initiating component (FIC) from an independent component analysis (ICA) were calculated. A linear regression analysis was conducted studying the vergence peak velocity as a function of the near dissociated phoria where the Pearson correlation coefficient was computed. Results: Before vergence therapy, the average with one standard deviation FIC magnitude of convergence responses from CI subjects was 0.29° ± 0.82 and significantly less than the FIC magnitude of 1.85° ± 0.84 for BNC (p < 0.02). A paired t-test reported that the FIC and near dissociated phoria before vergence therapy for CI subjects significantly increased to 1.49° ± 0.57 (p < 0.04) and became less exophoric to 3.5Δ ± 1.9 exo (p < 0.02) after vergence therapy. A significant correlation (r = 0.87; p < 0.01) was observed between the near dissociated phoria and the vergence ratio of convergence peak velocity divided by divergence peak velocity. Conclusion: The results have clinical translational impact in understanding the mechanism by which vergence therapy may be changing the vergence system leading to a sustained reduction in visual symptoms.

Purpose To evaluate the Proview Eye Pressure Monitor as a medical instrument and as a technique for enabling a patient to obtain an accurate measure of his or her intraocular pressure (IOP). Design An experimental laboratory evaluation and an independent prospective clinical study to test the reproducibility and accuracy of the Proview technique relative to Goldmann applanation tonometry. Participants For the laboratory study, we analyzed 3 tonometers, each packaged as a Proview Eye Pressure Monitor by Bausch & Lomb. In the independent prospective experimental study, 137 subjects participated, consisting of healthy volunteers and glaucoma patients. Methods For laboratory testing, we held each tonometer with a micrometer to assure controlled positioning and pressed its sensing tip against a force meter that produced a calibrated, digital force reading. For clinical testing, we taught subjects (n = 137) to use the Proview technique in accordance with the manufacturer's instructions. Each subject obtained 5 measurements with each of the 5 different Proview devices. A clinician measured the IOP using Goldmann applanation tonometry. Main outcome measures We measured the absolute value, linearity, and repeatability of the force meter readings on the tonometers during the instrument laboratory evaluation. The accuracy was evaluated by comparing the Proview measurements to the Goldmann applanation measurements. Reproducibility of clinical Proview measurements was also measured. All measurements were in mmHg during the clinical evaluation. Results Laboratory: There was a linear relationship between the pressures read by the Proview tonometers and known forces. The Proview tonometers read the maximum pressure applied. Clinical: The Proview technique is simple to use because it was comfortable and reproducible, with an average variance of the measurements by the same patient of 3.4 mmHg 2 . Other variables besides IOP seem to affect the Proview pressure measurements, as seen in the large scatter in our data, measured by our correlation coefficient of r = 0.41. The sensitivity of the Proview technique to detect patients with high IOP (which we defined as a Goldmann pressure of ≥22 mmHg) is low; the Proview pressure identified only 18% (4/22) of these patients. Conclusions The Proview instrument and technique were reproducible. However, the Proview tonometer seems not to be reliable as an indicator of IOP. The sensitivity for detecting high IOP was low in this cohort, and the agreement with Goldmann applanation was poor for some individuals. This brings into question the underlying assumption that a force proportional to the IOP generates phosphenes.

Convergence insufficiency (CI) is a prevalent binocular vision disorder with symptoms that include double/blurred vision, eyestrain, and headaches when engaged in reading or other near work. Randomized clinical trials support that Office-Based Vergence and Accommodative Therapy with home reinforcement leads to a sustained reduction in patient symptoms. However, the underlying neurophysiological basis for treatment is unknown. Functional activity and vergence eye movements were quantified from seven binocularly normal controls (BNC) and four CI patients before and after 18 h of vergence training. An fMRI conventional block design of sustained fixation vs. vergence eye movements stimulated activity in the frontal eye fields (FEF), the posterior parietal cortex (PPC), and the cerebellar vermis (CV). Comparing the CI patients' baseline measurements to the post-vergence training data sets with a paired t-test revealed the following: (1) the percent change in the BOLD signal in the FEF, PPC, and CV significantly increased (p < 0.02), (2) the peak velocity from 4° symmetrical convergence step responses increased (p < 0.01) and (3) patient symptoms assessed using the CI Symptom Survey (CISS) improved (p < 0.05). CI patient measurements after vergence training were more similar to levels observed within BNC. A regression analysis revealed the peak velocity from BNC and CI subjects before and after vergence training was significantly correlated to the percent BOLD signal change within the FEF, PPC, and CV (r = 0.6; p < 0.05). Results have clinical implications for understanding the behavioral and neurophysiological changes after vergence training in patients with CI, which may lead to the sustained reduction in visual symptoms.

While a body of literature relating cognition and oculomotor performance exists, a better understanding of these processes would help facilitate the development of effective treatments for patients suffering various neurological disorders, such as Multiple Sclerosis (MS), Huntington's Disease, or a traumatic brain injury. To examine the relationship between the two, we sought to measure cognition and oculomotor functioning simultaneously, through a modification of a commonly used neuropsychological test, the Symbol Digit Modalities Test (SDMT). Measurement includes monitoring of eye movements in two dimensions with the aid of infrared tracking. This paper presents preliminary data and an overview of analytical methods to be performed in the future on patients with neurological disorders. Correlations between eye movements and the mSDMT were verified using signal characterization. Furthermore, saccadic velocity was shown to remain relatively constant in healthy controls.

While fMRI has identified which regions of interests (ROI) are functionally active during a vergence task (the inward or outward rotation of eyes), the functional connectivity between ROIs is less understood. This study tested the following hypotheses: 1) significant functional connectivity would be observed between the frontal eye fields (FEF), the posterior parietal cortex (PPC) and the cerebellar vermis (CV), 2) significantly more functional activity and connectivity would be observed in binocularly normal controls (BNC) compared to patients with convergence insufficiency (CI), and 3) after vergence training, the functional activity and connectivity would improve in CI subjects compared to their baseline measurements. A block design of sustained fixation versus vergence eye movements stimulated activity in the FEF, PPC and CV. FMRI data from four CI subjects before and after vergence training were compared to seven BNC. Functional activity was assessed using the BOLD percent signal change. Functional connectivity was assessed using a seed-based functional connectivity analysis, which revealed significant correlation between the FEF, PPC and CV ROIs.

This research quantified clinical measurements and functional neural changes associated with vision therapy in subjects with convergence insufficiency (CI).Convergence and divergence 4° step responses were compared between 13 control adult subjects with normal binocular vision and four CI adult subjects. All CI subjects participated in 18 h of vision therapy. Clinical parameters quantified throughout the therapy included: nearpoint of convergence, recovery point of convergence, positive fusional vergence at near, near dissociated phoria, and eye movements that were quantified using peak velocity. Neural correlates of the CI subjects were quantified with functional magnetic resonance imaging scans comparing random vs. predictable vergence movements using a block design before and after vision therapy. Images were quantified by measuring the spatial extent of activation and the average correlation within five regions of interests (ROI). The ROIs were the dorsolateral prefrontal cortex, a portion of the frontal lobe, part of the parietal lobe, the cerebellum, and the brain stem. All measurements were repeated 4 months to 1 year post-therapy in three of the CI subjects.Convergence average peak velocities to step stimuli were significantly slower (p = 0.016) in CI subjects compared with controls; however, significant differences in average peak velocities were not observed for divergence step responses (p = 0.30). The investigation of CI subjects participating in vision therapy showed that the nearpoint of convergence, recovery point of convergence, and near dissociated phoria significantly decreased. Furthermore, the positive fusional vergence, average peak velocity from 4° convergence steps, and the amount of functional activity within the frontal areas, cerebellum, and brain stem significantly increased. Several clinical and cortical parameters were significantly correlated.Convergence peak velocity was significantly slower in CI subjects compared with controls, which may result in asthenopic complaints reported by the CI subjects. Vision therapy was associated with and may have evoked clinical and cortical activity changes.

Glaucoma is the degeneration of the optic nerve head caused by elevated intraocular pressure (IOP) and diurnal variations. It is the second leading cause of blindness. Proper treatment requires IOP to be monitored and maintained. Goldmann applanation tonometry is the clinical gold standard measured in the physician's office quarterly for those who are glaucoma suspects. It requires a local anesthetic administered to the cornea. Hence, this procedure cannot be utilized for patient home monitoring. The proposed tonometer to be used by a patient at home will use a sensor that measures force through the eye lid (transpalpebral) with a portable microcontroller device. The microcontroller will digitize data to be stored and transferred for offline analysis as well as display a single reading to an LCD display.

Presbyopia is part of the aging process where the eye losses the ability to focus at different depths. Progressive additive lenses (PALs) are routinely prescribed to facilitate the accommodation system for those with presbyopia. However, it is unknown why some individuals are more likely to adapt to PALs compared to others. Eighteen subjects who had all tried PALs participated in a vergence motor learning experiment. Peak velocity was measured. A generalized morphological component analysis (GMCA) was applied to ensemble vergence response data to dissect responses into their preprogrammed transient and feedback controlled sustained component. Results show that subjects with a greater peak velocity were more likely to adapt to progressive lenses. The transient component from GMCA was highly correlated to peak velocity suggesting that the larger the magnitude of the transient component the more likely a presbyope was to adapt to PALs.

Convergence insufficiency is a vision dysfunction in which people have difficulties performing visual tasks close to them such as reading. Symptoms include headaches, eye strain, blurred and double vision, and visual fatigue. Four subjects participated in 18 hours of vision rehabilitation consisting of home and laboratory sessions. During a longitudinal study, subjects performed a simple vergence oculomotor learning task during an fMRI experiment. Spatial extent and average correlation were quantified in the following regions of interest: the frontal lobe, parietal lobe, cerebellum, and brainstem. Preliminary data suggest improved neuronal synchronization and recruitment quantified through average correlation and spatial extent respectively when comparing the blood oxygenation level dependent signal before versus after rehabilitation. These changes were sustained during a follow-up session.

This study investigated the underlying components of vergence responses in binocularly healthy individuals and subjects with convergence insufficiency (CI). Convergent and divergent eye movements were recorded from seven subjects using step stimuli. In addition, four CI subjects participated in six weeks of vision rehabilitation. The goal of this study was to use an independent component analysis (ICA) algorithm to dissect the vergence responses into two underlying components (transient and sustained) for comparison. Preliminary data suggest the healthy controls have greater peak velocity and the magnitude of the transient component was larger compared to patients with CI. After training, the peak velocity and magnitude of the transient component increased for the CI patients and these behaviors were maintained after the training. Data suggest that training modifies the cortical signal responsible for generating the transient component signal and these changes are sustained post rehabilitation.

Presbyopia is a universal vision problem caused by the aging process. Progressive addition lenses (PALs) are a preferred solution; however, some patients can not adapt to the lenses. The acceptability is not well understood. Sixteen presbyopic subjects (9 subjects adapted to progressive lenses (PL) and 7 subjects who could not adapt to progressive lenses (PD) ) participated in a motor learning study. The motor learning experiment recorded baseline and modification responses where the dynamics of the 4° step responses were compared. Results show that both baseline and modified convergence dynamics were significantly greater in PLs compared to PDs. An adaptive neural network (ANN) classification technique using the baseline and modification velocity parameters with a linear classifier resulted in 94% correct classification. Therefore, baseline 4° convergence dynamics and its modification rate may be used as indicators to predict progressive addition lens acceptability among presbyopes.

Convergence insufficiency (CI) is a prominent vergence dysfunction. The purpose of this study is to investigate the underlying components of vergence responses in CI patients. Two, four and six degree convergent steps at two different initial positions and four degree divergent step stimuli were presented to three CI subjects. The goal was to use an independent component analysis (ICA) algorithm to dissect the vergence responses into two components (the transient and sustained) for comparison. Preliminary data show that the transient component of the vergence system is modified after six weeks of optometric vision training. Data suggest that neuroplasticity is evoked via optometric vision training implying training modifies a portion of the brain responsible for generating the transient component signals.

Diffusion tensor imaging (DTI) analysis is performed on a subject that exhibits visual dysfunction as a result of mild traumatic brain injury (TBI). A comparison is made of the subject's DTI data before and after undergoing vision training in order to quantify any differences in the subject's fractional anisotropy (FA) and white matter fiber tracts. A marked increase is seen in the FA values of the designated regions of interest (ROI) as well as in the number of fibers that are present in the ROIs.

All humans will become presbyopic as part of the aging process where the eye losses the ability to focus at different depths. Progressive additive lenses (PALs) allow a person to focus on objects located at near versus far by combing lenses of different strengths within the same spectacle. However, it is unknown why some patients easily adapt to wearing these lenses while others struggle and complain of vertigo, swim, and nausea as well as experience difficulties with balance. Sixteen presbyopes (nine who adapted to PALs and seven who had tried but could not adapt) participated in this study. This research investigated vergence dynamics and its adaptation using a short-term motor learning experiment to asses the ability to adapt. Vergence dynamics were on average faster and the ability to change vergence dynamics was also greater for presbyopes who adapted to progressive lenses compared to those who could not. Data suggest that vergence dynamics and its adaptation may be used to predict which patients will easily adapt to progressive lenses and discern those who will have difficulty.

Adaptation is critical to the survival of any species and is present in many systems within the brain. Rehabilitation can evoke neuroplasticity through adaptive mechanisms. Four subjects with the vision dysfunction of convergence insufficiency where two have mild traumatic brain injury and two were congenital participated in 18 hours of vision training. Clinical, behavioral, functional imaging and diffusion tensor imaging (DTI) are measured before and after therapy. Clinical parameters show improvement. Vergence eye-movements show an increase in peak velocity where independent component analysis revealed an increase in the magnitude of the preprogrammed transient component. Functional imaging using an oculomotor learning task shows increased area and intensity of activation suggesting neuronal recruitment and synchronization. DTI shows an increase in fractional anisotropy and an increase in the number of fibers suggesting changes in structural connectivity. Preliminary data suggest that neuroplasticity from vision training results in a change in behavioral oculomotor neural control through an increased magnitude of the preprogrammed disparity transient component potentially caused in part by neuronal recruitment, synchronization and improved structural connectivity.

Presbyopia, a degenerative condition, which decreases accommodation, sets in approximately at the age of forty. One approach to correct presbyopia is the use of bifocal or progressive lenses. Naturally, some people are more prone to adapt to wearing progressive lenses than others. The vergence system, which controls the inward and outward turning of the eyes, is a system which supports viewing objects in depth. Identifying the two components (transient and sustained components) of a pure vergence eye movement is possible with ICA (independent component analysis). Preliminary results suggest a correlation with the magnitude of the transient component and whether or not a person can adapt to wearing progressive lenses or not. Furthermore, the transient component of vergence is hypothesized to be an index of how flexible the vergence system is in adapting to new environments.

Presbyopia occurs from the aging process where accommodation decreases due to ciliary muscle weakness and loss of elasticity in the crystalline lens. People begin to have symptoms such as blurred vision, approximately at 40 years of age. To facilitate vision, presbyopes will wear multiple glasses, bifocals or progressive lenses. Progressive lenses can be difficult to adapt or learn how to wear. To date, patients are given little to no instruction on how to wear progressive lenses. The goal of this research is to predict who will have difficulties wearing the lenses and who will not. Other biomedical studies have shown that entropy which quantifies the energy content in physiological time-series data can be an indicator for how a person will adapt to changes or stress within the environment. Four degree convergence eye movement data (the inward turning of the eyes) from 10 people (4 Non-Presbyopes, 3 Presbyopes who have tried to wear the lenses but could not adjust, and 3 Presbyope who wear the lenses daily) were collected over 3 seconds and analyzed using sample entropy. Entropy values were obtained for each second of the response (0 tol, 1 to 2. and 2 to 3) and for the entire response (0 to 3 sec). Results were compared using a T-test and categorized using a clustering algorithm. The results showed that Sample Entropy classified the presbyopes who could adapt to the lenses compared to those who could not with 83% accuracy where the difference in entropy resulted in a P value of 0.1059.

Presbyopia, a degenerative condition, which decreases accommodation, sets in approximately at the age of forty. One approach to correct presbyopia is the use of bifocal or progressive lenses. Naturally, some people are more prone to adapt to wearing progressive lenses than others. The vergence system, which controls the inward and outward turning of the eyes, is a system which supports viewing in depth. Identifying the two components (transient and sustained components) of a pure vergence eye movement is possible with ICA (Independent Component Analysis). Preliminary results suggest a correlation with the magnitude of the transient component and whether or not a person can adapt to wearing progressive lenses or not. Furthermore, the transient component of vergence is hypothesized to be an index of how flexible the vergence system is in adapting to new environments.

Research suggests that fluctuations in diurnal intraocular pressure (IOP) are a significant independent risk for glaucoma progression. An effective self-tonometer and a clinical method for its use by the patient at home would help the management of glaucoma. We describe a prototype of a new tonometer that may prove useful for non-invasive self-tonometry. Preliminary data suggests that the device is locating the area of IOP by calculating the force required. to deform the cornea at a given time.

Many people are hindered by vision dysfunctions. One of the most prominent vergence dysfunctions in society is convergence insufficiency (CI) affecting 7% of the population. This study inspects the dynamics of convergence movements in both CI and normal binocular vergence subjects. Two stimulus types, a four degree and six degree step, were presented to an subjects. The goal was to determine if the dynamics of CI subjects were different compared to subjects with normal binocular vergence. Using the main sequence analysis, data show the dynamics of CI subjects were in the normal range as those who had normal binocular vergence, but were on the lower end. This study shows the dynamics of Cl subjects, whom have not had vision therapy, are slower when initiating a convergence movement.

PURPOSE: To assess the potential peak velocity asymmetry between the left-eye and right-eye movement responses stimulated by symmetrical vergence steps in those with normal binocular vision and those with convergence insufficiency (CI) before and after vergence training. This study also evaluated whether vergence training influenced convergence peak velocity and the prevalence of saccades within the first second of the response. METHODS: The peak velocities of the left-eye, right-eye, and combined vergence response evoked from symmetrical 2°, 4°, and 6° convergence step stimuli were assessed in 10 controls and 7 CI subjects. Four of the CI subjects participated in vergence training. An asymmetry ratio was calculated as the peak velocity of the slower eye movement response divided by the peak velocity of the faster eye movement response. RESULTS: Controls were significantly more symmetrical (left-eye peak velocity was approximately equal to right-eye peak velocity) compared to CI subjects (P < 0.001). After vergence training, the CI subjects' left-eye and right-eye movements became significantly more symmetrical, convergence peak velocity increased, and the prevalence of saccades within the first 1 second decreased (P < 0.01). Peak convergence velocity was significantly correlated to the prevalence of saccades observed within the first second of the response (r = 0.8; P < 0.05). CONCLUSIONS: Data suggest that vergence training improves the symmetry between the left-eye and right-eye movements, increases convergence peak velocity, and decreases the prevalence of saccades within the first second of the response, which facilitates binocular coordination in CI patients. Saccades may be a compensatory mechanism used by CI subjects when convergence peak velocity is reduced.

Most patients with glaucoma exhibit elevated intraocular pressure (IOP). A cost effective device that allows the patient to measure IOP at regular intervals may reduce vision loss. This research tested the Bausch & Lomb Proview self tonometer against a calibrated force meter. It further compared the Proview tonometer with results from the clinical gold standard, the Goldmann tonometer. Results show that the Proview tonometer has inaccuracies in calibration and uncertainties in clinical applications. If the Proview's calibration is corrected (using our results, e.g.), and the inaccuracies can be reduced, a device like the Proview has the potential to be clinically useful.