Eye tonometry : Procedures and assessments video series
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ABSTRACT:
SUBMITTER: Garcia-Rodriguez J
PROVIDER: S-EPMC3576944 | biostudies-literature |
REPOSITORIES: biostudies-literature
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| S-EPMC3625085 | biostudies-literature
Project description:Pavlovian eye blink conditioning (EBC) has been extensively studied in humans and laboratory animals, providing one of the best-understood models of learning in neuroscience. EBC has been especially useful in translational studies of cerebellar and hippocampal function. We recently reported a novel extension of EBC procedures for use in sheep, and now describe new advances in a digital video-based system. The system delivers paired presentations of conditioned stimuli (CSs; a tone) and unconditioned stimuli (USs; an air puff to the eye), or CS-alone "unpaired" trials. This system tracks the linear distance between the eyelids to identify blinks occurring as either unconditioned (URs) or conditioned (CRs) responses, to a resolution of 5 ms. A separate software application (Eye Blink Reviewer) is used to review and autoscore the trial CRs and URs, on the basis of a set of predetermined rules, permitting an operator to confirm (or rescore, if needed) the autoscore results, thereby providing quality control for accuracy of scoring. Learning curves may then be quantified in terms of the frequencies of CRs over sessions, both on trials with paired CS-US presentations and on CS-alone trials. The latency to CR onset, latency to CR peak, and occurrence of URs are also obtained. As we demonstrated in two example cases, this video-based system provides efficient automated means to conduct EBC in sheep and can facilitate fully powered studies with multigroup designs that involve paired and unpaired training. This can help extend new studies in sheep, a species well suited for translational studies of neurodevelopmental disorders resulting from gestational exposure to drugs, toxins, or intrauterine distress.
| S-EPMC5418117 | biostudies-literature
Project description:PurposeTonometry is widely used as the main screening tool supporting glaucoma diagnosis. Still, its accuracy could be improved if full knowledge about the variation of the corneal biomechanical properties was available. In this study, Optical Coherence Tomography (OCT) speckle statistics are used to infer the organisation of the corneal micro-structure and hence, to analyse its influence on intraocular pressure (IOP) measurements.MethodsFifty-six subjects were recruited for this prospective study. Macro and micro-structural corneal parameters as well as subject age were considered. Macro-structural analysis included the parameters that are associated with the ocular anatomy, such as central corneal thickness (CCT), corneal radius, axial length, anterior chamber depth and white-to-white corneal diameter. Micro-structural parameters which included OCT speckle statistics were related to the internal organisation of the corneal tissue and its physiological changes during lifetime. The corneal speckle obtained from OCT was modelled with the Generalised Gamma (GG) distribution that is characterised with a scale parameter and two shape parameters.ResultsIn macro-structure analysis, only CCT showed a statistically significant correlation with IOP (R2 = 0.25, p<0.001). The scale parameter and the ratio of the shape parameters of GG distribution showed statistically significant correlation with IOP (R2 = 0.19, p<0.001 and R2 = 0.17, p<0.001, respectively). For the studied group, a weak, although significant correlation was found between age and IOP (R2 = 0.053, p = 0.04). Forward stepwise regression showed that CCT and the scale parameter of the Generalised Gamma distribution can be combined in a regression model (R2 = 0.39, p<0.001) to study the role of the corneal structure on IOP.ConclusionsWe show, for the first time, that corneal micro-structure influences the IOP measurements obtained from noncontact tonometry. OCT speckle statistics can be employed to learn about the corneal micro-structure and hence, to further calibrate the IOP measurements.
| S-EPMC5417684 | biostudies-literature
Project description:PurposeModern cataract surgery is generally considered to bring about modest and sustained intraocular pressure (IOP) reduction. However, the pathophysiological mechanism for this remains unclear. Moreover, a change in ocular biomechanical properties after surgery can affect the measurement of IOP. The aim of the study is to investigate ocular biomechanics, before and following cataract surgery, using Corvis ST tonometry (CST).Patients and methodsFifty-nine eyes of 59 patients with cataract were analyzed. IOP with Goldmann applanation tonometry (IOP-G), axial length, corneal curvature and CST parameters were measured before cataract surgery and, up to 3 months, following surgery. Since CST parameters are closely related to IOP-G, linear modeling was carried out to investigate whether there was a change in CST measurements following cataract surgery, adjusted for a change in IOP-G.ResultsIOP-G significantly decreased after surgery (mean±standard deviation: 11.8±3.1 mmHg) compared to pre-surgery (15.2±4.3 mmHg, P<0.001). Peak distance (the distance between the two surrounding peaks of the cornea at the highest concavity), maximum deformation amplitude (the movement of the corneal apex from the start of deformation to the highest concavity) and A1/A2 velocity (the corneal velocity during inward or outward movement) significantly increased after cataract surgery (P<0.05) while radius (the central curvature radius at the highest concavity) was significantly smaller following cataract surgery (P<0.05). Linear modeling supported many of these findings, suggesting that peak distance, maximum deformation amplitude and A2 velocity were increased, whereas A2 deformation amplitude and highest concavity time were decreased (after adjustment for IOP change), following cataract surgery.ConclusionCorneal biomechanical properties, as measured with CST, were observed to change significantly following cataract surgery.Trial registrationJapan Clinical Trials Registry UMIN000014370.
| S-EPMC5319737 | biostudies-literature
Project description:Using measures of reflex impairment and injury to quantify an aquatic organism's vitality have gained popularity as survival predictors of discarded non-target fisheries catch. To evaluate the robustness of this method with respect to 'rater' subjectivity, we tested inter- and intra-rater repeatability and the role of 'expectation bias'. From video clips, multiple raters determined impairment levels of four reflexes of beam-trawled common sole (Solea solea) intended for discard. Raters had a range of technical experience, including veterinary students, practicing veterinarians, and fisheries scientists. Expectation bias was evaluated by first assessing a rater's assumption about the effect of air exposure on vitality, then comparing their reflex ratings of the same fish, once when the true air exposure duration was indicated and once when the time was exaggerated (by either 15 or 30 min). Inter-rater repeatability was assessed by having multiple raters evaluate those clips with true air exposure information; and intra- and inter-rater repeatability was determined by having individual raters evaluate a series of duplicated clips, all with true air exposure. Results indicate that inter- and intra-rater repeatability were high (intra-class correlation coefficients of 74% for both), and were not significantly affected by background type nor expectation bias related to assumed impact from prolonged air exposure. This suggests that reflex impairment as a metric for predicting fish survival is robust to involving multiple raters with diverse backgrounds. Bias is potentially more likely to be introduced through subjective reflexes than raters, given that consistency in scoring differed for some reflexes based on rater experience type. This study highlights the need to provide ample training for raters, and that no prior experience is needed to become a reliable rater. Moreover, before implementing reflexes in a vitality study, it is important to evaluate whether the determination of presence/absence is subjective.
| S-EPMC7043772 | biostudies-literature
Project description:Purpose:Video games provide a promising platform for rehabilitation of speech disorders. Although video games have been used to train speech perception in foreign language learners and have been proposed for aural rehabilitation, their use in speech therapy has been limited thus far. We present feasibility results from at-home use in a case series of children with velopharyngeal dysfunction (VPD) using an interactive video game that provided real-time biofeedback to facilitate appropriate nasalization. Method:Five participants were recruited across a range of ages, VPD severities, and VPD etiologies. Participants completed multiple weeks of individual game play with a video game that provides feedback on nasalization measured via nasal accelerometry. Nasalization was assessed before and after training by using nasometry, aerodynamic measures, and expert perceptual judgments. Results:Four participants used the game at home or school, with the remaining participant unwilling to have the nasal accelerometer secured to his nasal skin, perhaps due to his young age. The remaining participants showed a tendency toward decreased nasalization after training, particularly for the words explicitly trained in the video game. Conclusion:Results suggest that video game-based systems may provide a useful rehabilitation platform for providing real-time feedback of speech nasalization in VPD. Supplemental Material:https://doi.org/10.23641/asha.5116828.
| S-EPMC5544406 | biostudies-other
Project description:BackgroundStress echocardiography is a cost-effective tool for the modern noninvasive diagnosis of coronary artery disease. Several physical and pharmacological stresses are used in combination with echocardiographic imaging, usually exercise, dobutamine and dipyridamole. The safety of a stress is (or should be) a major determinant in the choice of testing. Although large scale single center experiences and multicenter trial information are available for both dobutamine and dipyridamole stress echo testing, complications or side effects still can occur even in the most experienced laboratories with the most skilled operators.Case presentationWe decided to present a case collection of severe complications during pharmacological stress echo testing, including a ventricular tachycardia, cardiogenic shock, transient ischemic attack, torsade de pointe, fatal ventricular fibrillation, and free wall rupture.ConclusionWe believe that, in this field, every past complication described is a future complication avoided; what happens in your lab is more true of what you read in journals; and Good Clinical Practice is not "not having complications", but to describe the complications you had.
| S-EPMC1224859 | biostudies-literature
Project description:Experienced teachers pay close attention to their students, adjusting their teaching when students seem lost. This dynamic interaction is missing in online education. We hypothesized that attentive students follow videos similarly with their eyes. Thus, attention to instructional videos could be assessed remotely by tracking eye movements. Here we show that intersubject correlation of eye movements during video presentation is substantially higher for attentive students and that synchronized eye movements are predictive of individual test scores on the material presented in the video. These findings replicate for videos in a variety of production styles, for incidental and intentional learning and for recall and comprehension questions alike. We reproduce the result using standard web cameras to capture eye movements in a classroom setting and with over 1,000 participants at home without the need to transmit user data. Our results suggest that online education could be made adaptive to a student's level of attention in real time.
| S-EPMC7865179 | biostudies-literature
Project description:IntroductionParkinson's disease (PD) research is hampered by slow, inefficient recruitment and burdensome in-person assessments that may be challenging to conduct in a world affected by COVID-19. Fox Insight is an ongoing prospective clinical research study that enables individuals to participate in clinical research from their own homes by completing online questionnaires. To date, over 45,000 participants with and without PD have enrolled. We sought to validate self-reported PD diagnosis in the Fox Insight cohort, assess the validity of other self-reported health information, and evaluate the willingness of participants to participate in video-based research studies.MethodsIndividuals with and without self-reported PD enrolled in Fox Insight were invited to participate in this virtual research study. Participants completed online questionnaires and two virtual visits, during which we conducted standard cognitive and motor assessments. A movement disorder expert determined the most likely diagnosis, which was compared to self-reported diagnosis.ResultsA total of 203 participants from 40 U.S. states, 159 with remote clinician-determined PD and 44 without, completed the study (59% male, mean (SD) age 65.7 (9.8)). Level of agreement between self-reported PD diagnosis in Fox Insight and clinician-determined diagnosis was very good ((kappa = 0.85, 95% CI 0.76-0.94). Overall, 97.9% of participants were satisfied with the study, 98.5% were willing to participate in a future observational study with virtual visits, and 76.1% were willing to participate in an interventional trial with virtual visits.ConclusionAmong the Fox Insight cohort, self-reported diagnosis is accurate and interest in virtual research studies is high.
| S-EPMC8299965 | biostudies-literature
Project description:ImportanceAccurate determination of intraocular pressure (IOP) is crucial for the diagnosis and management of glaucoma. Objective clinical evaluation of the correction equations for Goldmann applanation tonometry (GAT) is lacking.ObjectivesTo investigate the difference between corrected and conventional GAT and Pascal dynamic contour tonometry (DCT) measurements, as well as the correlation between discordant IOP values and stage of glaucoma.Design, setting, and participantsThis prospective cross-sectional case series was conducted at the Department of Ophthalmology, University Hospital Zurich, and Talacker Eye Center between July 1, 2011, and May 31, 2016, among 112 white patients with glaucoma.InterventionsIntraocular pressure measurements were performed with GAT and DCT in a randomized order. Goldmann applanation tonometry measurements were modified with 5 correction equations.Main outcomes and measuresThe primary end point was degree of concordance between corrected or uncorrected GAT and DCT measurements. The secondary end point was association between discordant IOP measurements and the stage of glaucoma, as assessed by the Glaucoma Severity Score.ResultsAmong the 112 patients (67 women and 45 men; mean [SD] age, 66.3 [13.1] years), 63 of the eyes in the study (56.3%) were left eyes and 85 patients (75.9%) were taking ocular antihypertensive medications. Mean (SD) IOP was 20.3 (4.5) mm Hg (95% CI, 19.4-21.1) as measured by DCT and 17.0 [4.1] mm Hg (95% CI, 16.3-17.8) as measured by GAT. The mean (SD) discordance between DCT and GAT measurements was -3.3 (2.0) mm Hg (95% CI, 2.9-3.6). The 5 corrected GAT values ranged from -2.7 to -5.4 mm Hg compared with DCT. The mean (SD) result of the Dresdner correction formula (17.6 [4.1] mm Hg) was closer to the DCT measurement than the original GAT measurement. The mean (SD) Glaucoma Severity Score was 4.7 (3.4) (95% CI, 4.1-5.4). The uncorrected discordance IOPDCT - IOPGAT showed a positive correlation with the Glaucoma Severity Score (rs = 0.33; P < .001) and a negative correlation with central corneal thickness (rs = -0.22; P = .02).Conclusions and relevanceIn comparison with DCT measurements, these data suggest that GAT values are significantly discordant in eyes with thin corneas and advanced glaucoma. Application of GAT-based correction formulas involves a possible risk of creating an even greater number of unpredictable measurement errors. Hence, we advise with caution, especially pertaining to eyes with thin corneas, to not place reliance on GAT readings, and abandon any correction formula.Trial registrationclinicaltrials.gov Identifier: NCT01474070.
| S-EPMC5540028 | biostudies-literature