Two tests to measure fusional vergence amplitudes objectively were developed and validated against the two conventional clinical tests. Forty-nine adults participated in the study. Participants’ negative (BI, base in) and positive (BO, base out) fusional vergence amplitudes at near were measured objectively in an haploscopic set-up by recording eye movements with an EyeLink 1000 Plus (SR Research). Stimulus disparity changed in steps or smoothly mimicking a prim bar and a Risley prism, respectively. Break and recovery points were determined offline using a custom Matlab algorithm for the analysis of eye movements. Fusional vergence amplitudes were also measured with two clinical tests using a Risley prism and a prism bar. A better agreement between tests was found for the measurement of BI than for BO fusional vergence amplitudes. The means ± SD of the differences between the BI break and recovery points measured with the two objective tests were -1.74 ± 3.35 PD and -1.97 ± 2.60 PD, respectively, which were comparable to those obtained for the subjective tests. For the BO break and recovery points, although the means of the differences between the two objective tests were small, high variability between subjects was found (0.31 ± 6.44 PD and -2.84 ± 7.01 PD, respectively). This study showed the feasibility to measure fusional vergence amplitudes objectively and overcome limitations of the conventional subjective tests. However, these tests cannot be used interchangeably due to their poor agreement.

Eye movement control is impaired in some neurological conditions, but the impact of COVID-19 on eye movements remains unknown. This study aims to investigate differences in oculomotor function and pupil response in individuals who suffer post-COVID-19 condition (PCC) with cognitive deficits. Saccades, smooth pursuit, fixation, vergence and pupillary response were recorded using an eye tracker. Eye movements and pupil response parameters were computed. Data from 16 controls, 38 COVID mild (home recovery) and 19 COVID severe (hospital admission) participants were analyzed. Saccadic latencies were shorter in controls (183 ± 54 ms) than in COVID mild (236 ± 83 ms) and COVID severe (227 ± 42 ms) participants (p = 0.017). Fixation stability was poorer in COVID mild participants (Bivariate Contour Ellipse Area of 0.80 ± 1.61°² vs 0.36 ± 0.65 °² for controls, p = 0.019), while percentage of pupil area reduction/enlargement was reduced in COVID severe participants (39.7 ± 12.7%/31.6 ± 12.7% compared to 51.7 ± 22.0%/49.1 ± 20.7% in controls, p < 0.015). The characteristics of oculomotor alterations found in PCC may be useful to understand different pathophysiologic mechanisms.

To compare the performance in the Developmental Eye Movement test (DEM) and the Test of Visual Perceptual Skills (TVPS) between three groups: individuals with strabismus and amblyopia, patients with binocular and accommodative dysfunctions, and subjects with normal binocular and accommodative function. A multicentric, retrospective study including 110 children aged 6-14 years old was conducted to investigate the potential impact of strabismus, amblyopia, and different binocular conditions in DEM results (adjusted time in vertical and horizontal parts) and TVPS (percentiles in the seven sub-skills). No significant differences were found in the different subtests of the vertical and horizontal DEM and all the sub-skills in the TVPS between the three groups of the study. We found high variability of performance in the DEM test between participants with strabismus and amblyopia compared with binocular and accommodative problems. DEM and TVPS scores have not been found to be influenced by the presence of strabismus with or without amblyopia, nor by binocular and accommodative dysfunctions. A slightly correlation tendency with horizontal DEM and degree of exotropia deviation was observed.

Action video game (AVG) players have been reported to demonstrate improved perceptual, cognitive, and motor skills, as well as enhanced eye movements such as saccade latency and accuracy. This study examined if these improvements are also observed in two common clinical eye movement assessments, the Developmental Eye Movement (DEM) and King–Devick tests. Ninth and tenth graders (15–16 years old) without learning disabilities or oculomotor dysfunctions, and who do not regularly play ball sports were tested in the DEM and King–Devick tests in random order. Those playing AVG ≥ 5 hours per week were included in the AVG group, and those playing ≤ 1 h per week were included in the non-video game group (NVG). Participants were asked to read quickly while reading speed and errors were recorded. Two DEM subtests were read vertically and one subtest was read from left to right. All King–Devick subtests were read from left to right. Forty participants (20 AVG, 20 NVG, 15 girls, mean age: 15.7 ± 0.1 years) were included. AVG players were significantly faster in their horizontal DEM times (AVG: 26 ± 5, NVG: 34 ± 7 sec, p < 0.001) and King–Devick times (AVG: 14 ± 2, NVG: 16 ± 4 sec, p = 0.034), but not in their vertical DEM times (AVG: 26 ± 3, NVG: 28 ± 5 sec p = 0.063). King-Devick and horizontal DEM times were significantly correlated for the entire sample (p < 0.01). Teenagers who regularly played AVGs performed better on the DEM and King–Devick tests, indicating that regularly playing this genre of AVGs may enhance oculomotor skills and visual processing speed. Clinicians should take this into account when interpreting results of these clinical tests.

Introduction: Vision therapy is an effective treatment option for binocular vision and accommodative anomalies. However, its effect on typical binocular vision is less documented. The aim of this study was to evaluate objectively the change in near fusional vergence amplitudes in adults with typical binocular vision after performing a vision therapy protocol. Methods: Thirty‐four adults were randomly classified into an experimental group (EG), who underwent a vision therapy protocol for 12 weeks, and a control group (CG), who received a placebo treatment for 12 weeks (Phase 1). In Phase 2, the CG performed the same therapy protocol as the EG. Fusional vergence amplitudes were measured objectively in a haploscopic set‐up using smooth and step fusional vergence tests. The break points of positive and negative fusional vergence (PFV and NFV, respectively) were determined using a custom algorithm. Results: After Phase 1, there were no significant differences between the groups for fusional vergences. After Phase 2, PFV and NFV increased significantly as measured with the smooth and step tests ( p = 0.002 and p < 0.001 for NFV and p = 0.03 and p = 0.02 for PFV, respectively). These improvements were maintained after 1 month without any further intervention (all p > 0.05). Conclusion: Based on these results, clinicians should consider that the vergence system cannot be trained beyond 2 and 5 Δ for NFV and PFV, respectively, when aiming to enhance vergence skills with vision therapy in patients without binocular dysfunctions.

Introduction: Fusional reserves differ with the method of measurement. The goal of this study was to compare the subjective and objective responses during the measurement of positive and negative fusional reserves using both step and ramp methods. Methods: A haploscopic system was used to measure fusional reserves. Eye movements were recorded using an EyeLink 1000 Plus eye tracker (SR Research). The stimulus disparity was changed to either mimic a prism bar (steps) or a Risley prism (ramp). Subjective responses were obtained by pressing a key on the keyboard, whereas objective break and recovery points were determined offline using a custom algorithm coded in Matlab. Results: Thirty‐three adults participated in this study. For the ramp method, the subjective and objective responses were similar for the negative (break and recovery points ( t (32) = −0.82, p = 0.42) and ( t (32) = 0.42, p = 0.67), respectively) and positive fusional reserves (break and recovery points ( U = −1.34, p = 0.18) and t (19) = −0.25, p = 0.81), respectively). For the step method, no significant differences in positive fusional reserves were observed when measured subjectively and objectively for the break ( t (32) = 1.27, p = 0.21) or the recovery point ( U = −2.02, Bonferroni‐adjusted p = 0.04). For the negative fusional reserve, differences were not significant for either the break or recovery points ( U = −0.10, p = 0.92 and t (19) = 1.17, p = 0.26, respectively). Conclusion: Subjective and objective responses exhibited good agreement when measured with the ramp and step methods.