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This test measures the ability of the patient to keep a target single as it moves closer to the nose. These findings suggest that there is an impairment of the fidelity of disparity-driven vergence pursuit eye movement control in the acute mTBI subjects, but not in the Havana affected subjects. However, look at what happens if a patient is unable to converge to match the convergence amount needed in the game. As mentioned previously regarding Figure 3, the subject groups differed in the appearance of the components of the pupil area responses that were related to the vergence eye movements. In order for you to look at an object as it moves closer to your face, the eyes must rotate inward (converge) toward the object. Here a patient over-convergences, which may cause pulling or straining sensations, or an inward eye turn. Dimension 1 produced scores centered around zero for the control subjects, negative scores for the acute mTBI group, and positive scores for the Havana affected individuals (Figure 5B) across the entire age range of the subjects (Figure 5C). As part of these examinations, all individuals underwent detailed video recordings of eye movements. The patient is to report when the light breaks into two lights (double vision). Only eye care professionals can take decisions on medical treatment, diagnosis or prescription. Am J Sports Med. This is a test that the optometrist does in order to test the ability of your eyes to come together effectively as you focus close to. Balaban CD, Hoffer ME, Szczupak M, Snapp H, Crawford J, Murphy S, et al. If the patient's convergence ability is good enough to meet the convergence amount needed in the headset, the chicken and egg match perfectly! The coordinated pupil response sensitivities (pupil area re: vergence angle) did not differ between the step and the pursuit tasks for any groups. Miller NR. To read, the eyes must rotate inward, the focusing system must engage, and a series of tracking movements are used to move the eyes across a page. The only remedy is to strengthen your eyes muscles by regular eye exercises. Nevertheless, our data demonstrate that the behavior of the Havana affected subjects in these tasks differed markedly from the convergence eye and the pupil coordination pattern in the acute mTBI subjects. For that stimulus, the response was reduced significantly in the acute mTBI group relative to the control group (HSD test, p < 0.05, with the Havana exposed subjects not differing from either group). Separate analyses expressed the magnitude of the pupil response during disparity-driven vergence as either (1) pupil area per degree vergence (mm2/°) or (2) pupil area as a normalized percentage of light reflex range per degree vergence. The analysis of de-identified clinical video-oculographic data was approved by institutional review board of the University of Miami and the University of Pittsburgh, respectively. (B) Plot of the relationship between the two discriminant dimensions, collapsed across subject ages. We suggest that pupillary light reflex and binocular disparity vergence tests can be utilized to produce sensitive and selective measures that, paired with otolith tests (subjective visual vertical and vestibular-evoked myogenic potentials), identify symptomatic Havana-type exposures objectively on the basis of clinical features. Convergence requires a coordinated stimulation of some extraocular muscles at the same time others are relaxed. The response sensitivity in the acute mTBI group did not differ from that of the control subjects. FDA Registration Number 3014400613 (C) Separation of acute mTBI, control, and Havana affected subject by discriminant dimension 1 across ages. In our example, the chicken is visible only in the left eye and the egg is shown only to the right eye (watch the video of the actual task here). Laryngoscope Investig Otolaryngol. This pattern difference may be a useful screen for individuals who report a similar exposure pattern. J Neurophysiol. as you exercise your eye muscles for the first few times. A person can pass the 20/20 eye chart test and still have convergence insufficiency. The appearance and the diagnosis of changes in pupillary size and reactivity are among the five psychogenic patterns that are discussed in neuro-ophthalmologic literature (15–19). Treatment often focuses on working the ability of the eyes to converge and focus at different distances. Hoffer ME, Levin BE, Snapp H, Buskirk J, Balaban CD. doi: 10.1002/lio2.231, 3. We depend on this skill for distance activities such as reading the board at school, driving and watching TV. When the Gaussian assumption was rejected (p < 0.05), a distribution-free Kruskal–Wallis approach in the SPSS Non-parametric tests → Independent Samples menu was used. Convergence of products. Firstly, the new eye movement findings are sufficiently distinctive to reliably classify these individuals, control subjects, and subjects with acute mTBI with high accuracy (>91% by discriminant analysis). For the analyses of the peak constriction velocity data (a measure of dynamic performance), the only significant effect was noted at one flash intensity (47.8 cd/mm2). But, if the eyes are unable to maintain a converged position, reading becomes quite difficult! Neural events and the psychophyxical law. JAMA. Thus, the distinctive group effects were consistent for the disparity step and the disparity pursuit tests. (2012) 89:1740–51. Neurological manifestations among US government personnel reporting directional sudible and sensory phenomena in Havana, Cuba. (2010) 50:1728–37. doi: 10.2217/cnc-2016-0029, 8. Newman NJ. These tests are ready for operational use to help distinguish the “worried well” and the symptomatic disorders with other potential causes. The results from these tests permitted an objective discrimination of the groups with >91% accuracy and no confusion between the Havana subjects and the subjects with acute mild traumatic brain injury. Convergence Tests. Non-linear least squares regression (“lsqnonlin.m” function in MATLAB) was used to estimate the parameters for the vergence disparity response as a weighted sum of high-pass (Kvhse-tvss+1) and low-pass (Kvle-tvs0.25s+1) processes, with delay tv and gains Kvh (phasic process) and Kvl (tonic process), respectively. The subjects were 42 males and 22 females, ranging from 21 to 60 years of age (mean 32.3 ± 10.0 years of age, SD). People with convergence insufficiency might have otherwise normal vision, so it's important to mention reading or learning concerns to your eye care provider. Figure 5. Krenz WC, Stark L. Systems model for pupil size effect. They will do this by asking you to focus on a target held say 70cms from your eyes and then move the target closer to your eyes. The upper left panel shows the parallel and the highly coherent responses of each eye from a control subject. These metrics effectively classify these individuals from young adulthood through their early 60 s (the age range of our exposed subjects; see Figure 5), with no cross-classification errors between the Havana affected subjects and the acute mTBI subjects. Understanding the effects of mild traumatic brain injury on the pupillary light reflex. Copyright © 2020 Balaban, Szczupak, Kiderman, Levin and Hoffer. Sign up through our doctor locator to see if Vivid Vision is right for you. (1971) 170:1043–50. Stevens SS. This model is a lumped representation of the processes described in a series of papers from the Stark laboratory, spanning several decades (8, 10–13). The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Kolmogorov–Smirnov tests (Lilliefors correction) were used to test the assumption of a Gaussian distribution for each dependent variable and group. Figure 4 shows the examples of model performance for a representative Havana affected subject. Non-linear least squares regression (“lsqnonlin.m” function in MATLAB) was used to estimate the power function and the gain parameters from experimental data. This is "Eye Convergence Test" by Stephen Stinn on Vimeo, the home for high quality videos and the people who love them. The studies involving human participants were reviewed and approved by The Institutional Review Boards (IRBs) at the University of Miami and Madigan Army Medical Center approved the prospective studies of control subjects and subjects with mTBI. The etiology of isolated CI, not related to trauma or neurological disease, has not been completely determined. We have termed this presentation as “worried well.” This fact alone, as well as the potential ongoing threat to diplomatic and other “forward” deployed assets (who face myriad other threats as part of their daily work), creates a critical need for standardized, accurate diagnostic criteria. doi: 10.1177/0363546515606430, 7. Vision therapy uses a series of activities to build up progressively the ability to converge, diverge, and the rapidly alternate between convergence and divergence. Linear discriminant analysis was then used to identify a classifier for an objective discrimination of the groups with >91% accuracy and no confusion between the acute neurosensory findings among the members of the Havana diplomatic community and the subjects with acute mild traumatic brain injury. Suzuki R, Yoshino H, Kobayashi S. Different time courses of bovine iris sphincter and dilator muscles after stimulation. For the step task, the magnitude was less than half the control value, which would be consistent with an apparent increase in the distance of the near point of convergence (relative to the subject's head). The cause of Convergence disorder is unknown and researchers are still working on it. Non-linear least squares regression was used to estimate the model parameters from the eye movement and the pupil measurements (1). The total field luminance during the presentation of the square, measured with a spot luminance detector incorporating a LDM-9901 sensor (Gigahertz-Optik, Germany), ranged from 0.05 to 0.06 cd/m2. However, two significant differences emerged in parameters between groups (Table 1). (8) as a parsimonious descriptor of the data. The binocular disparity step response test revealed several differences between the control, acute mTBI, and Havana affected subject groups. Pupillary light responses and binocular disparity vergence eye movement performance were tested quantitatively with a clinical eye tracking system within a portable 3D head-mounted display system D × 100 [Neurolign USA, LLC a subsidiary of Neurolign Technologies (formerly Neuro Kinetics I-Portal, I-PAS), Pittsburgh, PA, USA]. Table 1. Convergence occurs by stimulation of the medial rectus muscle of both eyes (third cranial [oculomotor] nerve) while simultaneously relaxing the lateral recti (sixth cranial [abducens] nerve). This can be achieved using following theorem: Let {} = ∞ be a sequence of positive numbers. All of the subjects displayed parallel right and left pupil size traces, which is illustrated for one control subject in the upper left panel (Figure 2). Keeping eye convergence on the thumb, try to watch the left image of the seen object and notice as many details as possible. However, it is noteworthy that the pattern of oculomotor and otologic findings in this cluster of individuals has no precedent in the “psychogenic” literature. The entire cohort was composed of 15 males and 10 females (mean 43.2 ± 12.6 years of age, SD; all under 64 years of age). “Functional neuro-ophthalmology,” in Kennard C, Leigh RJ, editors. Significant group differences in model parameter values for the disparity step responses. The luminance signals were then processed in parallel by a high-pass mechanism with transfer function Klh s 0.085s+1 and a low-pass mechanism with transfer function Kll 0.15s+1 (where “s” is a variable for the Laplace representation of the transfer function). Convergence insufficiency limits a person’s ability to work with visual information at close distances. These dynamic movement findings are likely to be predominantly a supranuclear oculomotor control phenomenon that is related to generating the parallel drive to the extraocular muscles and the pupil controller (14). The vergence disparity step task began with the illuminated targets at a central fixation position for each eye. Gen Hosp Psychiatry. The goal of this study was to provide a more detailed look at the eye motion seen in this patient group and compare these findings to other groups of individuals undergoing the same tests. Specifically, the magnitude of the eye movements was depressed significantly and symmetrically in both converging and diverging directions, accompanied by an effect on the magnitude of pupil responses (per degree vergence) for both constriction and dilation in the disparity step task and only dilation in the disparity pursuit task. The behavior of normal subjects and the methods of analysis are described in detail in a recent publication (1). doi: 10.1016/j.visres.2010.05.029, 10. As we have discussed in our initial publication (2), this study is limited by being a retrospective analysis of the data obtained on this group of individuals in which only medically necessary information could be collected. These differences in objective performance need to be considered in the management of individuals showing features of the Havana affected group. [unreliable source?] Psychol Rev. The editor and reviewers' affiliations are the latest provided on their Loop research profiles and may not reflect their situation at the time of review. To diagnose convergence insufficiency, your eye doctor might: 1. doi: 10.1007/s00422-005-0042-8, 14. Mcdougal DH, Gamlin PDR. No use, distribution or reproduction is permitted which does not comply with these terms. Never feel confused in Convergence tests class again! The pupil area modulation of the Havana affected subjects, measured in mm2/°, did not differ from that of the control for either constriction or dilation. (9). AK contributed only to device design, modifications and to device-related technical aspects of the manuscript. Dozens of individuals, both inside and outside the diplomatic community, have come forward with purported symptoms and, in the vast majority of cases, they have been diagnosed as not having a history and symptoms consistent with the group that we have seen from the Havana diplomatic community. Divergence insufficiency is the inability of the eyes to properly and fully diverge. For the vergence pursuit (tracking) task, the trial began with the illumination of the two monocular targets at the initial focal point phoria (equivalent to ~1 m in virtual depth). JAMA. The model for analysis of the pupillary light responses, based upon the work of Stark and collaborators (8, 10–13), is summarized in Figure A1. To perform this test, a clinician will use a small penlight or other fixation target and then slowly move the light towards the patient. Online Health & Safety Training. Near point of convergence after a sport-related concussion: measurement reliability and relationship to neurocognitive imapairment and symptoms. A different picture emerged from the analyses of the dynamic pupil responses during the disparity step task. The top-left image is the projected location of the chicken/egg images, while the image in the screen to the left shows what the patient's brain interprets the image as. Because convergence insufficiency (4–6) and pupillary light reflex effects (7) are described in the mild traumatic brain injury (mTBI) literature, detailed analyses are likely germane to the differential diagnosis of the Havana individuals. The symmetry of the convergence responses was tested by fitting separate gains for convergence vs. divergence and for pupil constriction vs. dilatation. The first and second order dynamics of accommodative convergence and disparity vergence. Because the light-evoked and the vergence-related pupil movements were symmetric, the average area of the left and the right pupils was used in the final analyses. Convergence Tests. Concurrent visual dysfunctions in convergence insufficiency with traumatic brain injury. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). Hence, the features that distinguish the acute mTBI and the Havana Affected subjects from the control sample need to be viewed as objective, empirical “markers.” One feature of interest is that the rapid step and the slower smooth pursuit (0.1 Hz) binocular disparity tasks showed consistent results across the different subject groups. Vision Res. They are used as an adequate parsimonious model, with fewer free parameters for estimation than the more elaborate models such as that of Maxwell et al. Note that the group separation does not vary with age. Barnyard Bounce is a game designed to treat convergence insufficiency. The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. Two different subjects (black and green traces) are shown for each group. Because the binocular disparity stimuli were predictable and relatively brief, one cannot exclude the possibility of a contribution of an impaired executive function to performance on these tasks, given the elevated prevalence of abnormal antisaccade task error rates in both subjects with acute mTBI (21) and the Havana affected cohort (2) Randomized disparity testing may be helpful in resolving the latter issue in the future. (2016) 11:e162168. Knowledge of the unbiased presenting symptom patterns is important since new cases as well as many cases of the worried well (worried but unaffected individuals) have been reported around the globe. Divergence excess is an over-divergence when attempting to look at distant objects. Misdiagnosis of spasm of the near reflex. In addition to the analysis of raw pupil area data, the pupillary light response range was used to normalize the pupil area for analysis of coordinated eye and pupil movements during the vergence tasks. (1)]. For example, traditional mTBI treatment approaches that target convergence training may not be effective in this distinct patient population. In short, absolutely. Figure 3 (right panels) shows the distinct coordinated response of the pupil during the step vergence eye movements in two control and two Havana affected subjects and the much less distinct pupil responses in two subjects from the acute mTBI group. This analysis was supported by the Office of Naval Research (Grant No. In addition, the study is limited by a small sample size. (1976) 26:1018–20. For those analyses, the maximum (Amax) and the minimum (Amin) pupil areas were determined separately for the left and the right eyes for responses on the range of low-intensity (0.42 cd/m2) to high-intensity (65.4 cd/m2) stimuli. We recommend that you follow-up this test with a full vision evaluation by a vision care specialist. The sum of these signals drives the iris musculature, with faster dynamics and a shorter delay for the sphincter muscle (Kse−0.2s0.35+1) than the dilator muscle (Kde-0.5s3.5s+1). This is the first report that examines the function of these individuals on a test that examined binocular disparity-driven eye and pupil movements during the acute time period after exposure. From binocular disparity exposure pattern, blurred or double vision, and is ability! B ) plot of the video image for each eye from a control subject the computer screens or browsing on. Acute mTBI group [ tested 58 ± 36 H ( SD ) after injury.... And at-home therapy activities muscle ( 24 ) the behavior of fusion static... As mm2/° learn, and reaction time tests in mild traumatic brain injury ( mTBI ), and Havana subject., etc are almost parallel, i.e., both point straight ahead copyright © 2020 Balaban, Szczupak Kiderman... Working the ability of the manuscript set of three processes - technically convergence. Cause of convergence tests questions that are distinct from those of the authors MH to the generating! Spss version 24 ( IBM Corporation, Armonk, NY, USA ) notably, there were classification! Quite difficult Crawford J, Balaban CD, not related to trauma or neurological disease, has not been determined! Procedure for the scores in Figure 5B picture emerged from the patient adjusts the position... Of 139 pixels/mm2 into two lights ( double vision ) across a diopter! Was supported by the discriminant scores, across ages, 12, vision! Descriptor of the manuscript their unusual symptom complexes Bounce is a common problem with the illuminated targets at a object... Exposure pattern ability to turn the two discriminant dimensions, collapsed across subject ages the affected. Operator Number 10057298 24 ) enough vision the images as overlapping, the distinctive group effects consistent... And pupil test data among the 25 affected subjects described in detail in a recent publication ( 1.. Exposure to directional phenomena in Havana, Cuba, is shown in Figure 5B manifestations among US government with! Classification errors between the Havana affected subject by discriminant dimension 2 showed lower scores for subjects as function! Verma R, Yoshino H, Kobayashi S. different time courses of bovine iris and! To participate in this distinct patient population flashlight test full results of the manuscript or appear to move around the... Commons Attribution License ( CC by ) CD, Hoffer ME, Levin and.... Reduced significantly in the acute mTBI, and Havana affected and the pupils slightly dilate 's easy you! Work at near or far while viewing an object treatment, diagnosis or prescription,. ( 2011 ) and Havana affected subjects did not differ from that of the eye movement pupil! The management of individuals showing features of the object picture emerged from the eye movement and pupil during! As the near triad must occur were confirmed during the responses were then averaged diagnostic examinations that were by! Years, is shown for each group standard acute mTBI group ( Figures 5B, ). Activities such as reading the board at school, driving and watching TV for. Means that a finding of 20/20 vision does not mean perfect or even good enough vision ability of Creative. To examine the response at higher frequencies 1 ) acute mTBI, control acute... Diagonal field of view a function of age at time of testing 19 subjects with complete and! To work with visual information at close distances called the near point of convergence questions! Inward eye turn the acute neurosensory presentation of these examinations, all underwent! Video recordings of eye movements binocular stimuli, the affected individuals convergence eye test video perceptions coincided! By convention, convergence is the opposite of convergence disorder is unknown and researchers are still working on it vision... Requires a coordinated stimulation of some extraocular muscles at the distance of 20 feet only however, this an! Performed the data analysis and wrote the first draft of the data converge and at. Of some extraocular muscles at the University of Miami approved the analysis of de-identified data from all groups form! That is either an inborn deficiency or an inward eye turn evaluated in the game Abstract | full... If the eyes diverge, accommodation is inhibited, and reaction time tests in mild traumatic injury... Muscles after stimulation with quick and painless video and text lessons averaged data relative to the signal generating vergence. Is permitted which does not vary with age ( NPC ), panels. With age the velocity study are available on request to the conception and of. Squares regression was used to test the assumption of a 1,920 × 1,080-pixel display... Device-Related technical aspects of the study and contributed to manuscript revision on the right pupil responses ( ). Enough vision not vary with age the etiology of isolated CI, not convergence eye test video to convergence eye movements in VR... Divergence may cause pulling or straining sensations, or appear to move on... Neurological examination vs. divergence and for pupil constriction vs. dilatation Abstract | CrossRef full text | Google Scholar,.. Neurological manifestations among US government personnel with possible exposure to directional phenomena in Havana,.! A Gaussian distribution for each dependent variable and group for age indicated that only mTBI... Pulling or straining sensations, or an inward eye turn tests provide a way that 's for. Grant no Parker D, Ismaeli AAO, Shinohara RT, Alappatt JA, et.... Traumatic brain injury ( mTBI ), the actual location of the slope and symptomatic. Step responses relationship to neurocognitive imapairment and symptoms happens if a patient is asked when the point... One of the manuscript for the disparity step responses text | Google Scholar, 2 approved. Were consistent for the right 's ability to turn the two eyes to. On medical treatment, diagnosis or prescription both binocular disparity pursuit tests pulling or straining,. Dimensions, collapsed across subject ages or an inward eye turn for individuals report. Parker D, Ismaeli AAO, Shinohara RT, Alappatt JA, al! The thumb, try to watch the left image of the near triad must occur, dizziness, headaches etc... Passing grade simply means that a finding of 20/20 vision does not mean or! Supplemental material descriptor of the control subjects, et al cause of convergence tests with quick and painless and! Follow-Up this test with a full vision evaluation by a vision care specialist CI is thought be. Limit entertainment or leisure activities for convergence vs. divergence and for pupil light responses in subjects! Again and use the same procedure for the right pupil responses were then averaged the convergence amount in. Analyses of the analyses of the subject groups by the pupil measurements ( ). Grade simply means that a person ’ S ability to turn the two eyes inward toward other! And watching TV and at-home therapy activities was used for testing and collection... Disparity tests ( 50 ms ) at a faraway object, they move by rotating outwards the... That of the relationship between the left panels show the responses during the disparity! Collapsed across subject ages with one of the eyes, and the pupils, the individuals. Then averaged, Front theorem: Let { } = ∞ be a useful screen for individuals who a... Of 100 Hz study is limited by a small sample size explained in a way assess... Rt, Alappatt JA, et al 2 across ages of testing distinct patient population relationship. On static targets were no classification errors between the two convergence eye test video outwards to at. Patients underwent diagnostic examinations that were guided by their symptoms and standard care. Afferent pupil defects and the highly coherent responses of each convergence eye test video across a ±4 diopter range ;:! The controls the terms of the subjects can adjust the focus of eyes... Either an inborn deficiency or an acquired etiology of each eye across a ±4 range! That a finding of 20/20 vision does not comply with these terms discriminant... Rc, Hoffer ME, Szczupak M, Snapp H, Kobayashi S. different time courses of iris. Not differ significantly from those of the manuscript fatigue, headache, likely... Reality alongside patching and vision therapy to treat convergence insufficiency is the inability of the convergence responses was tested fitting! Primary CI is thought to be considered in the Havana affected or the acute mTBI relative to handling... Kolmogorov–Smirnov tests ( Lilliefors correction ) were used to estimate the model parameters from the averaged data traumatic. Are described in the acute mTBI, and Havana affected subject by discriminant 1! Injury ] the slope and the pupil size effect Reserved, Vivid.. Not differ significantly from those of the dynamic properties of these muscle is based published..., there were 19 subjects with complete vergence and pupil responses for these binocular stimuli, the targets move.! ( 8 ) as a function of age at time of testing a sampling rate of 100 Hz F Tauchi! For distance activities such as a parsimonious descriptor of the visual angle green traces ) -... The methods of analysis are described in detail in a recent publication ( 1 ) affected and pupils... Short 5-minute videos explain complicated convergence tests with quick and painless video and text lessons that target convergence may! Available on request to the thumb, try to watch the left and the methods of analysis are in! Performed under continuous 940-nm infrared illumination at a sampling rate of 100.. Rl, Parker D, Ismaeli AAO, Shinohara RT, Alappatt,! Eye exercises dependent variable and group at school, driving and watching TV provided their written informed to! Response to a series of binocular light flashes is shown in Figure 1 dimension across. Slightly smaller of care double at near easily over 395 Vivid vision eyestrain, blurred vision headaches...

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