Clinical reading-related oculomotor assessment in visual snow syndrome / Evaluación oculomotora clínica relacionada con la lectura en el síndrome de nieve visual

Purpose: Visual snow syndrome (VSS) is a complex neurological condition presenting with an array of sensory, motor, and perceptual dysfunctions and related visual and non-visual symptoms. Recent laboratory studies have found subtle, basic, saccadic-based abnormalities in this population. The objective of the present investigation was to determine if saccadic-related problems could be confirmed and extended using three common clinical reading-related eye movement tests having well-developed protocols and normative databases. Methods: This was a retrospective analysis of 32 patients (ages 16–56 years) diagnosed with VSS in the first author's optometric practice. There was a battery of three reading-related tests: the Visagraph Reading Eye Movement Test, the Developmental Eye Movement (DEM) Test, and the RightEye Dynamic Vision Assessment Test, all performed using their standard documented protocols and large normative databases. Results: A high frequency of oculomotor deficits was found with all three tests. The greatest percentage was revealed with the Visagraph (56%) and the least with the RightEye (23%). A total of 77% of patients failed at least one of the three tests. Conclusion: The present findings confirm and extend earlier investigations revealing a high frequency of saccadic-based oculomotor problems in the VSS population, now including reading-related tasks. This is consistent with the more general oculomotor/motor problems found in these individuals.(AU)

Distance horizontal fusional facility (DFF): A new diagnostic vergence test for the acquired brain injury (ABI) population

Purpose To report the retrospectively-based, clinical diagnostic findings for the horizontal, distance, fusional facility (DFF) test in the non-TBI (traumatic brain inury), ABI (acquired brain injury) population. Methods The DFF test (4 pd base-out/2 pd base-in) was assessed and compared retrospectively in the first author's optometric practice in three clinical populations: (1) post-mTBI, visually-symptomatic (n = 52), (2) post-ABI, non-mTBI, visually-symptomatic (n = 34), and (3) visually-normal, visually asymptomatic (n = 44). Results The DFF values in each group were significantly different from each other (p < 0.05). The mean non-TBI, ABI group value was significantly lower than found in the mTBI group, and both were significantly lower than the mean found in the normal cohort (p < 0.05). There was a significant reduction in DFF with increased age (p < 0.001). ROC values for the AUC ranged from excellent to acceptable (0.94–0.74). Conclusion The DFF test is a new and useful way to assess horizontal, distance, dynamic, fusional facility in those with presumed non-mTBI, ABI neurological conditions to assist in its diagnosis. (AU)

Distance horizontal fusional facility (DFF): A new diagnostic vergence test for the acquired brain injury (ABI) population.

PURPOSE: To report the retrospectively-based, clinical diagnostic findings for the horizontal, distance, fusional facility (DFF) test in the non-TBI (traumatic brain inury), ABI (acquired brain injury) population. METHODS: The DFF test (4 pd base-out/2 pd base-in) was assessed and compared retrospectively in the first author's optometric practice in three clinical populations: (1) post-mTBI, visually-symptomatic (n = 52), (2) post-ABI, non-mTBI, visually-symptomatic (n = 34), and (3) visually-normal, visually asymptomatic (n = 44). RESULTS: The DFF values in each group were significantly different from each other (p < 0.05). The mean non-TBI, ABI group value was significantly lower than found in the mTBI group, and both were significantly lower than the mean found in the normal cohort (p < 0.05). There was a significant reduction in DFF with increased age (p < 0.001). ROC values for the AUC ranged from excellent to acceptable (0.94-0.74). CONCLUSION: The DFF test is a new and useful way to assess horizontal, distance, dynamic, fusional facility in those with presumed non-mTBI, ABI neurological conditions to assist in its diagnosis.

Clinical reading-related oculomotor assessment in visual snow syndrome.

PURPOSE: Visual snow syndrome (VSS) is a complex neurological condition presenting with an array of sensory, motor, and perceptual dysfunctions and related visual and non-visual symptoms. Recent laboratory studies have found subtle, basic, saccadic-based abnormalities in this population. The objective of the present investigation was to determine if saccadic-related problems could be confirmed and extended using three common clinical reading-related eye movement tests having well-developed protocols and normative databases. METHODS: This was a retrospective analysis of 32 patients (ages 16-56 years) diagnosed with VSS in the first author's optometric practice. There was a battery of three reading-related tests: the Visagraph Reading Eye Movement Test, the Developmental Eye Movement (DEM) Test, and the RightEye Dynamic Vision Assessment Test, all performed using their standard documented protocols and large normative databases. RESULTS: A high frequency of oculomotor deficits was found with all three tests. The greatest percentage was revealed with the Visagraph (56%) and the least with the RightEye (23%). A total of 77% of patients failed at least one of the three tests. CONCLUSION: The present findings confirm and extend earlier investigations revealing a high frequency of saccadic-based oculomotor problems in the VSS population, now including reading-related tasks. This is consistent with the more general oculomotor/motor problems found in these individuals.

Intraocular Pressure and Myopia Progression, Axial Length Elongation in Rural Chinese Children.

SIGNIFICANCE: This study reported the relationship between intraocular pressure (IOP) and myopia progression, which helps to understand more comprehensively whether IOP can be an important reference factor to intervene in the progression of myopia. PURPOSE: This study aimed to investigate the association between IOP and myopia progression as well as axial length elongation in rural Chinese children. METHODS: A total of 598 (598 of 878 [68.1%]) children (6 to 17 years) from the baseline Handan Offspring Myopia Study who completed a 3.5-year follow-up vision examination were included. Ocular examinations at both visits included cycloplegic autorefraction, IOP, and axial length measurements. RESULTS: Children with myopia had the highest baseline IOP of the three refractive groups (14.13 ± 1.31, 13.78 ± 1.71, and 13.59 ± 1.64 mmHg in myopes, emmetropes, and hyperopes, respectively, P = .002). However, IOPs showed no significant difference between eyes with or without newly developed myopia (13.63 ± 1.68 vs. 13.89 ± 1.68, P = .16), with or without faster myopia progression (13.75 ± 1.61 vs. 13.86 ± 1.63, P = .46), or with axial length elongation (13.80 ± 1.61 vs. 13.76 ± 1.64, P = .80). The multivariate regression analysis demonstrated that neither baseline refractive error ( ß = -0.082, P = .13) nor baseline axial length ( ß = -0.156, P = .08) was associated with baseline IOP. CONCLUSIONS: Myopic eyes have slightly higher IOP compared with emmetropic and hyperopic eyes, although it was not clinically significant. However, IOP was not found to be associated with either myopia progression or axial length elongation in this cohort sample of rural Chinese children.

Historical, Diagnostic, and Chromatic Treatment in Visual Snow Syndrome: A Retrospective Analysis.

PURPOSE: This study aimed to determine the historical, diagnostic, and treatment aspects in patients with documented visual snow syndrome/visual snow in an academic, optometric setting. METHODS: A retrospective analysis was performed in patients (N = 40, aged 12 to 55 years) with documented visual snow syndrome/visual snow examined over a 4-year period. Information was collected by a detailed case history and the Visual Snow Syndrome Symptom Survey. Treatment assessment was performed using the Intuitive Colorimeter, and a wide selection of chromatic tints was assessed under the most provocative/exacerbating and other conditions. RESULTS: Visual snow was typically constant and monochromatic, with it being present on average 6.43 years. Bright and dark surfaces were the most provocative/exacerbating/revealing conditions, along with the viewing of computer screens. The most common etiology was mild traumatic brain injury. The most common primary and secondary symptoms were photosensitivity and tinnitus, respectively. There was a high frequency of occurrence of oculomotor deficits, especially accommodative and vergence insufficiency (~40 to 50%). Eighty percent of the patients were prescribed a chromatic tint with subjective visual reduction of visual snow ranging from 15 to 100% (mean, 45%). CONCLUSIONS: The present information will help in understanding this unusual medicoperceptual condition, especially with respect to simple treatment frequently using readily available chromatic tints.

Pupillary Light Response Deficits in 4-Week-Old Piglets and Adolescent Children after Low-Velocity Head Rotations and Sports-Related Concussions.

Neurological disorders and traumatic brain injury (TBI) are among the leading causes of death and disability. The pupillary light reflex (PLR) is an emerging diagnostic tool for concussion in humans. We compared PLR obtained with a commercially available pupillometer in the 4 week old piglet model of the adolescent brain subject to rapid nonimpact head rotation (RNR), and in human adolescents with and without sports-related concussion (SRC). The 95% PLR reference ranges (RR, for maximum and minimum pupil diameter, latency, and average and peak constriction velocities) were established in healthy piglets (N = 13), and response reliability was validated in nine additional healthy piglets. PLR assessments were obtained in female piglets allocated to anesthetized sham (N = 10), single (sRNR, N = 13), and repeated (rRNR, N = 14) sagittal low-velocity RNR at pre-injury, as well as days 1, 4, and 7 post injury, and evaluated against RRs. In parallel, we established human PLR RRs in healthy adolescents (both sexes, N = 167) and compared healthy PLR to values obtained <28 days from a SRC (N = 177). In piglets, maximum and minimum diameter deficits were greater in rRNR than sRNR. Alterations peaked on day 1 post sRNR and rRNR, and remained altered at day 4 and 7. In SRC adolescents, the proportion of adolescents within the RR was significantly lower for maximum pupil diameter only (85.8%). We show that PLR deficits may persist in humans and piglets after low-velocity head rotations. Differences in timing of assessment after injury, developmental response to injury, and the number and magnitude of impacts may contribute to the differences observed between species. We conclude that PLR is a feasible, quantifiable involuntary physiological metric of neurological dysfunction in pigs, as well as humans. Healthy PLR porcine and human reference ranges established can be used for neurofunctional assessments after TBI or hypoxic exposures (e.g., stroke, apnea, or cardiac arrest).

Biometric and refractive changes following the monocular application of peripheral myopic defocus using a novel augmented-reality optical system in adults.

The prevalence of myopia is growing at an alarming rate and is associated with axial elongation of the eye. The cause of this undesirable physiological change involves multiple factors. When the magnitude of myopia approaches high levels, this accompanying mechanical effect increases the risk of developing other clinical conditions associated with permanent vision loss. Prior work has investigated how we may halt or reverse this process of axial elongation associated with myopic progression when we expose the eye to a peripheral myopic defocus stimulus. Specifically, the known, short-term response to myopic defocus stimulation is promising and demonstrates the possibility of establishing more permanent effects by regulating the axial length of the eye with specific defocus stimulation. However, how to directly convert these known, short-term effects into more long-term, permanent changes to effectively prevent these unfavourable physiological and refractive changes over time is yet to be understood. Here, we show for the first time that we can produce sustained, long-term reductions in axial length and refractive endpoints with cumulative short-term exposure to specific myopic defocus stimuli using a novel optical design that incorporates an augmented reality optical system. We believe that this technology will have the potential to improve the quality of vision in mankind.

Accommodative and pupillary dysfunctions in concussion/mild traumatic brain injury: A Review.

BACKGROUND: Visual dysfunctions are common in individuals following concussion/mild traumatic brain injury (C/mTBI). Many deficits have been uncovered in their oculomotor system, such as in the pupil and accommodation. OBJECTIVE: To describe the static and dynamic abnormalities in the pupillary and accommodative systems in those with C/mTBI. This includes both diagnostic and therapeutic aspects, with emphasis on objectively-based test findings, as well as their basic and clinical ramifications. METHODS: PubMed, Google Scholar, and Semantic Scholar databases were searched from 1980-2020, using key words of accommodation, pupil, vision therapy, vision rehabilitation, and objective testing, for peer-reviewed papers, as well as related textbooks in the area, in those with C/mTBI. RESULTS: For both systems, most static and dynamic response parameters were abnormal: they were typically reduced, slowed, delayed, and/or more variable. Most of the abnormal accommodative parameters could be significantly improved with vision therapy. CONCLUSIONS: For both systems, most response parameters were abnormal, which could explain their visual symptoms and related problems. For accommodation, the improvements following vision therapy suggest the presence of considerable visual system plasticity, even in older adults with chronic brain injury.

Objectively-based vergence and accommodative dynamics in mild traumatic brain injury (mTBI): A mini review.

Vergence and accommodation have been critical areas of investigation in those with mild traumatic brain injury (mTBI). In this mini-review, the major laboratory studies in the area using objective assessment of vergence and accommodative dynamics in this population are discussed. These include the basic findings, their diagnostic and therapeutic implications, potential study limitations, and suggested future research directions. All studies provided important new information, and insights, into the area. There were two key outcomes of the reviewed studies common to both the vergence and accommodative systems in those with mTBI. First, most dynamic parameter's responsivity at baseline was abnormal: it was slowed, delayed, and/or inaccurate as compared to the normative control data. Second, most of the abnormal dynamic parameter's responsivity could be remediated, at least in part, following a short period of oculomotor-based vision therapy, thus demonstrating considerable residual neuroplasticity in the damaged, human brain.

Refractive change and incidence of myopia among rural Chinese children: the Handan Offspring Myopia Study.

PURPOSE: To assess the refractive change and incidence of myopia, as well as their risk factors, among Chinese rural children aged 6-17 years. METHODS: Children who completed the baseline vision examination of the Handan Offspring Myopia Study were re-examined, including both cycloplegic and non-cyloplegic autorefraction, with a mean follow-up time of 42.4±1.47 months. RESULTS: A total of 601 children (68.5%) who completed both baseline and the follow-up examinations were enrolled. The cumulative refractive change and axial length change were -0.53±1.03 diopter and 0.39±0.46 mm (-0.15 diopter/year and 0.11 mm/year), respectively. A hundred and five out of the 469 non-myopic children at baseline become myopic at the follow-up, yielding a cumulative myopia incidence of 22.4% (95% CI: 18.6% to 26.2%), or annual myopia incidence of 6.3%. After adjustment, younger age (ß=0.08, p<0.001), more myopic baseline refraction (ß=0.31, p<0.001), larger difference between cycloplegic and non-cycloplegic refraction (ß=-0.20, p=0.007) and more myopic paternal refraction (ß=0.09, p=0.007) were found to be associated with more rapid myopic refractive change. More myopic baseline refraction (relative risk (RR), 95% CI: 0.19, 0.13-0.28, p<0.001) and more myopic paternal refraction (RR, 95% CI: 0.92, 0.84-1.00, p=0.039) were also associated with myopia incidence. CONCLUSION: Relatively low myopic refractive change and myopia incidence were found in this study cohort. Children's refraction and paternal refraction were associated with both myopic refractive change and myopia incidence. Such information will be helpful for further comparisons in other rural versus urban areas of China, and other countries.

Visual Performance as a Function of Clear Central Aperture Diameter with a Defocused Myopic Periphery.

SIGNIFICANCE: Visual performance is affected least by a 15° radial aperture surrounded by peripheral myopic defocus. This finding has important applications for spectacle and contact lens designs and myopia control optimization. PURPOSE: The purpose of this study was to assess the effect of clear central apertures of different diameters with a defocused retinal periphery, using a range of visual performance tasks. METHODS: Thirty visually normal subjects (mean age, 24.4 ± 3.3 years; 20 females; mean spherical equivalent of -1.28 D) were enrolled. Subjects wore five different spectacles during testing, all corrected for distance refraction, in random order: three single-vision spectacles with clear central apertures of 10, 12.5, and 15° radii with the periphery defocused using Fresnel "press-on" lenses (+3.5 D sphere), progressive addition lens (PAL) spectacles with a +3.5 D addition, and single-vision lens (SVL) spectacles with no peripheral defocus. Static and kinetic visual field sensitivities, reading rate and comprehension, head movements, global saccadic tracking, and saccadic visual search were evaluated. RESULTS: Reading rate and comprehension did not differ across the five test conditions; however, increased head movement was found with the smallest aperture compared with the PAL condition with adjusted P < .05. Static visual field sensitivity was reduced for all three apertures in eccentric regions when compared with the SVL and PAL conditions with adjusted P < .05, whereas kinetic sensitivity did not differ for any lens condition. The 15° aperture was superior to the 10 and 12.5° apertures based on its similarity to the SVL and PAL spectacle conditions in head movement during reading, the Michigan Tracking Test, and the vertical results of the Developmental Eye Movement Test. CONCLUSIONS: Visual performance is least affected adversely by a 15° aperture surrounded by a peripheral myopic defocus. This finding has important applications for spectacle and contact lens designs to optimize myopia treatment with minimal impact on visual performance.

Developmental Effects on Pattern Visual Evoked Potentials Characterized by Principal Component Analysis.

Purpose: Peak amplitude and peak latency in the pattern reversal visual evoked potential (prVEP) vary with maturation. We considered that principal component analysis (PCA) may be used to describe age-related variation over the entire prVEP time course and provide a means of modeling and removing variation due to developmental age. Methods: PrVEP was recorded from 155 healthy subjects ages 11 to 19 years at two time points. We created a model of the prVEP by identifying principal components (PCs) that explained >95% of the variance in a "training" dataset of 40 subjects. We examined the ability of the PCs to explain variance in an age- and sex-matched "validation" dataset (n = 40) and calculated the intrasubject reliability of the PC coefficients between the two time points. We explored the effect of subject age and sex upon the PC coefficients. Results: Seven PCs accounted for 96.0% of the variability of the training dataset and 90.5% of the variability in the validation dataset with good within-subject reliability across time points (R > 0.7 for all PCs). The PCA model revealed narrowing and amplitude reduction of the P100 peak with maturation, and a broader and smaller P100 peak in male subjects compared to female subjects. Conclusions: PCA is a generalizable, reliable, and unbiased method of analyzing prVEP. The PCA model revealed changes across maturation and biological sex not fully described by standard peak analysis. Translational Relevance: We describe a novel application of PCA to characterize developmental changes of prVEP in youths that can be used to compare healthy and pathologic pediatric cohorts.

Cone parameters in different vision levels from the adaptive optics imaging.

ABSTRACT: To investigate the relationship between visual resolution and cone parameters in eyes with different levels of best corrected visual acuity (BCVA).Seventeen eyes of 10 volunteers with BCVA of 20/12.5 or better (group 1) and 16 eyes of 10 volunteers with BCVA of 20/16 (group 2) were investigated in the study. Images of the cone photoreceptors at 1.5° from the fovea were obtained using an adaptive optics (AO) retinal camera. The BCVA was obtained following a subjective refraction using a standardized logMAR visual acuity chart.The mean cone density (29,570.96 ±â€Š2489.94 cells/mm2) at 1.5° from the fovea in group 1 (BCVA ≥ 20/12.5, n = 17) was significantly greater (P < .001) than that (22,963.59 ±â€Š2987.92 cells/mm2) in group 2 (BCVA = 20/16, n = 16). The cone spacing at 1.5° from the fovea in group 1 was 6.45 ±â€Š0.28 µm (mean ±â€ŠSD), which was significantly smaller (P < .001) than 7.36 ±â€Š0.50 µm (mean ±â€ŠSD) in group 2. In the stepwise regression analysis, greater angular cone density (odds ratio [OR], 4.48; P = .005) and smaller angular cone spacing (OR, 0.60; P = .007) at 1.5° from the fovea were significantly associated with the better BCVA.The greater cone density and smaller cone spacing at the parafovea were found in eyes with BCVA of 20/12.5 or better, as compared to that in eyes with BCVA of 20/16. Knowledge of cone distribution for different BCVA levels may be beneficial for different clinical conditions.

The association between nearwork-induced transient myopia and progression of refractive error: A 3-year cohort report from Beijing Myopia Progression Study

PURPOSE: To investigate the natural change of nearwork-induced transient myopia (NITM), and its association with the progression of refractive error. METHODS: Students of the Beijing Myopia Progression Study were examined at baseline and follow-up examinations, which included cycloplegic autorefraction. Initial NITM and its decay were assessed objectively immediately after binocularly-viewing and performing a sustained 5-minute near task (20 cm). RESULTS: There were 223 students with both NITM and cycloplegic refractive data enrolled. There were 142 myopic (63.7%), 32 emmetropic (14.4%), and 49 hyperopic (22.0%) students according to their baseline cycloplegic refraction. The annual refractive change was -0.45 (-0.73, -0.21) D. From the baseline to the one-year and two-year follow-up periods, the initial NITM (median) increased significantly in the myopic students (0.16, 0.21, and 0.20D, p = 0.01, respectively). The overall proportion of NITM decay types shifted significantly from none being induced at baseline (non-induced: 17.0%, complete decay 57.4%, incomplete decay 25.6%) to incomplete decay at the 2-year follow-up (non-induced: 6.7%, complete decay 65.0%, incomplete decay 28.3%, p = 0.01). For the hyperopic students, after adjusting for risk factors, for every 1 diopter increase in the initial NITM at baseline, there was approximately a -1.48 diopter more relative myopic refractive progression (p = 0.01). No significant association was found between refractive change and the NITM parameters for either the myopic or emmetropic students after adjusting for the same confounders. However, this relation was significant in the hyperopes (p = 0.01). CONCLUSION: NITM was only found to be significantly associated with the progression of a myopic refractive shift among the hyperopes

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The association between nearwork-induced transient myopia and progression of refractive error: A 3-year cohort report from Beijing Myopia Progression Study.

PURPOSE: To investigate the natural change of nearwork-induced transient myopia (NITM), and its association with the progression of refractive error. METHODS: Students of the Beijing Myopia Progression Study were examined at baseline and follow-up examinations, which included cycloplegic autorefraction. Initial NITM and its decay were assessed objectively immediately after binocularly-viewing and performing a sustained 5-minute near task (20 cm). RESULTS: There were 223 students with both NITM and cycloplegic refractive data enrolled. There were 142 myopic (63.7%), 32 emmetropic (14.4%), and 49 hyperopic (22.0%) students according to their baseline cycloplegic refraction. The annual refractive change was -0.45 (-0.73, -0.21) D. From the baseline to the one-year and two-year follow-up periods, the initial NITM (median) increased significantly in the myopic students (0.16, 0.21, and 0.20D, p = 0.01, respectively). The overall proportion of NITM decay types shifted significantly from none being induced at baseline (non-induced: 17.0%, complete decay 57.4%, incomplete decay 25.6%) to incomplete decay at the 2-year follow-up (non-induced: 6.7%, complete decay 65.0%, incomplete decay 28.3%, p = 0.01). For the hyperopic students, after adjusting for risk factors, for every 1 diopter increase in the initial NITM at baseline, there was approximately a -1.48 diopter more relative myopic refractive progression (p = 0.01). No significant association was found between refractive change and the NITM parameters for either the myopic or emmetropic students after adjusting for the same confounders. However, this relation was significant in the hyperopes (p = 0.01). CONCLUSION: NITM was only found to be significantly associated with the progression of a myopic refractive shift among the hyperopes.