Objective Eye Tracking Metrics of Vision and Autonomic Dysfunction Distinguish Adolescents With Acute Concussion and Those with Persistent Post-Concussion Symptoms from Uninjured Controls

ObjectiveTo explore the utility of an eye-tracking assessment in distinguishing binocular alignment, saccadic movement, and pupillary dynamics among uninjured adolescents, acute cases (= 28 days since concussion), and persistent cases (>28 days since concussion).BackgroundVisual and autonomic system disturbances are common sequelae of concussion. Quantification of visual and autonomic dysfunction via an eye tracking device could provide an objective method of acute diagnosis and subacute identification of ongoing injury.Design/MethodsWe compared 347 eye tracking metrics, derived from a 220 seconds eye-tracking assessment, among 132 uninjured adolescents (mean age: 15.3, 56.2% female), 110 acute cases (mean days since injury: 12.5, mean age: 15.4, 46.4% female), and 95 persistent cases (mean days since injury: 53.6, mean age: 15.4, 70.2% female) using Kruskal-Wallis tests with Bonferroni corrections to account for multiple comparisons.ResultsNine eye-tracking metrics were significantly associated with injury status. One measure of binocular alignment (acute v. control: p = 0.003, persistent v. control: p = 0.001) and one measure of saccadic movement (acute v. persistent: p = 0.03, acute v. control: p = 0.03, persistent v. control: p < 0.001) were worse in cases. Cases had larger left and right mean and median pupil size than uninjured adolescents (acute v. control, p < 0.001; persistent v. control, p < 0.001). Cases had greater differences in mean (acute v. control: p < 0.001, persistent v. control: p < 0.001), median (acute v. control, p < 0.001, persistent v. control, p = 0.003), and variance of (acute v. control: p < 0.001, persistent v. control: p < 0.001) left and right pupil size. Eight of these metrics distinguished female cases from uninjured adolescents, but similar differences were not observed in male participants.ConclusionsObjective eye tracking technology can identify vision and pupillary disturbances after concussion. These metrics could be integrated into clinical practice to monitor recovery in a heterogeneous adolescent concussion population and may identify sex-specific differences in autonomic dysfunction.

Saccadic movement effects on intraocular drug delivery for a wet-AMD clinical case

Nowadays, intravitreal injections are the gold standard for the treatment of age-related macular degeneration (AMD). The prediction of the transport mechanism for the injected anti vascular endothelial growth factor (anti-VEGF) is needed in order to understand its distribution and consumption after each injection. Thus, this study aims at implementing a full model of vitreous drug delivery. The main novelty of this work is the coupling between an experimental evaluation of the scleral permeability and a numerical analysis of the saccadic dependency of the transport phenomena.

Investigation of Saccadic Eye Movement Effects on the Fluid Dynamic in the Anterior Chamber

The aqueous humor (AH) flow in the anterior chamber (AC) due to saccadic movements is investigated in this research. The continuity, Navier-Stokes and energy equations in 3D and unsteady forms are solved numerically and the saccadic motion was modeled by the dynamic mesh technique. Firstly, the numerical model was validated for the saccadic movement of a spherical cavity with analytic solutions and experimental data where excellent agreement was observed. Then, two types of periodic and realistic saccadic motions of the AC are simulated, whereby the flow field is computed for various saccade amplitudes and the results are reported for different times. The results show that the acting shear stress on the corneal endothelial cells from AH due to saccadic movements is much higher than that due to normal AH flow by buoyancy induced due to temperature gradient. This shear stress is higher on the central region of the cornea. The results also depict that eye saccade imposes a 3D complicated flow field in the AC consist of various vortex structures. Finally, the enchantment of heat transfer in the AC by AH mixing as a result of saccadic motion is investigated.