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.

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.

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.

Near work, outdoor activity, and myopia in children in rural China: the Handan offspring myopia study.

BACKGROUND: The near work and outdoor activity are the most important environmental risk factors for myopia. However, data from Chinese rural children are relatively rare and remain controversial. Therefore, the purpose of this study was to evaluate the relationship of both near work and outdoor activities with refractive error in rural children in China. METHODS: In this cross-sectional study, 572 (65.1%) of 878 children (6-18 years of age) were included from the Handan Offspring Myopia Study (HOMS). Information from the parents on these children, as well as the parent's non-cycloplegic refraction, were obtained from the database of the Handan Eye Study conducted in the years 2006-2007. A comprehensive vision examination, including cycloplegic refraction, and a related questionnaire, were assessed on all children. RESULTS: The overall time spent on near work and outdoor activity in the children was 4.8 ± 1.6 and 2.9 ± 1.4 h per day, respectively. Myopic children spent more time on near work (5.0 ± 1.7 h vs.4.7 ± 1.6 h, p = 0.049), while no significant difference was found in outdoor activity hours (2.8 ± 1.3 h vs. 3.0 ± 1.4 h, p = 0.38), as compared to non-myopic children. In the multiple logistic analysis, in general, no association between near work and myopia was found after adjusting for the children's age, gender, parental refractive error, parental educational level, and daily outdoor activity hours [odds ratio (OR), 95% confidence interval (CI): 1.10, 0.94-1.27]. However, a weak protective effect of the outdoor activity on myopia was found (OR, 95% CI: 0.82, 0.70-0.96), after adjusting for similar confounders. CONCLUSIONS: In general, no association between near work and myopia was found, except for the high near work subgroup with moderate outdoor activity levels. A weak protective effect of outdoor activity on myopia in Chinese rural children was observed.

Evaluation of the SVOne Handheld Autorefractor in a Pediatric Population.

PURPOSE: The SVOne is a portable, Hartmann-Shack wavefront aberrometer, which can be attached to a smartphone to determine the refractive error of the eye objectively. Previous results have shown the device to provide measurements equivalent to those of standard clinical techniques in young, healthy adults. The aim of the present study was to compare the findings of the SVOne with retinoscopy, subjective refraction, and two commercially available autorefractors (Retinomax-3 and WAM-5500) in a pediatric population. METHOD: The refractive error of the right eye was assessed both without and with cycloplegia in 40 visually normal children between 5 and 17 years of age (mean age = 11.3 years) using the five techniques described above. Further, to assess repeatability of the instruments, the entire procedure was repeated in a subgroup of five subjects. All data were analyzed in terms of power vectors (M, J0, and J45). RESULTS: No significant difference was observed between the mean values of M (spherical equivalent) for the different techniques. Retinoscopy showed the best agreement with subjective refraction, both without and with cycloplegia, followed by the open-field WAM-5500. The most repeatable procedures, when measured without and with cycloplegia, were the WAM-5500 and retinoscopy, respectively. Measurements with the SVOne showed a decline in repeatability under cycloplegia. CONCLUSIONS: The results indicate that the SVOne provides measurements of refractive error in a normal, pediatric population that are not significantly different from other subjective and objective procedures. Accurate alignment along the visual axis, especially when measuring through a dilated pupil, is critical. This instrument is valuable for vision screenings, for examinations taking place outside the clinical office, and a starting point for the refractive assessment.

The difference between cycloplegic and non-cycloplegic autorefraction and its association with progression of refractive error in Beijing urban children.

PURPOSE: To investigate the difference between cycloplegic and non-cycloplegic autorefraction and its association with the progression of refractive error in Beijing urban children. METHODS: A total of 386 children aged 6-17 years were enrolled in the baseline investigation of the Beijing Myopia Progression Study in 2010. They were invited for follow-up vision examinations in the years 2011, 2012, and 2013, including cycloplegic (cyclopentolate 1%, three times) autorefraction. We investigated the difference between the cycloplegic spherical equivalent (SE) and the non-cycloplegic SE (DSE) provided by autorefraction and its association with refractive error progression. The progression of refractive error was defined as the difference between the cycloplegic SE at follow-up and at baseline. RESULTS: Two hundred and nineteen children (57%) with completed refractive data (mean ± standard deviation: -1.36 ± 2.44 D at baseline) were ultimately enrolled. The DSE reduced from 0.51 ± 0.72 D at baseline to 0.19 ± 0.43 D in the third year of follow-up (p = 0.01). The baseline DSE was positively associated with the children's baseline cycloplegic refraction (ß = 0.193 dioptre dioptre-1 , p < 0.001). After further divided by refractive status, the DSE was consistently higher in the hyperopic group than in either the emmetropic or myopic groups at each follow-up (all p < 0.001). In the multivariate regression analysis, the myopic children with larger baseline DSE (ß = -0.404 dioptre dioptre-1 , p = 0.01) exhibited more myopic refractive change. However, baseline DSE was not found to be a significant risk factor (relative risk, 95% confidence interval: 1.06, 0.79-1.41) for those with newly developed myopia. CONCLUSION: In this sample, the children's DSE was found to be increased as the hyperopic refraction increased. Furthermore, greater the DSE was associated with the progression of refractive error among the myopic children, but not with the onset of myopia.

The influence of near work on myopic refractive change in urban students in Beijing: a three-year follow-up report.

PURPOSE: To investigate the influence of daily activities on myopic refractive change and myopic onset in Chinese urban students. METHODS: The Beijing Myopia Progression Study was a 3-year cohort study. Cycloplegic refraction and a daily activity questionnaire were assessed at baseline and at follow-up examinations. Refractive change was defined as the difference in cycloplegic spherical equivalent (SE) between the final follow-up and baseline. 386 students were initially enrolled in the baseline study. RESULTS: At the final follow-up, 222 students (57.5 %) with completed refractive error and daily activity data were analyzed. These students spent 0.32 ± 2.33 h/day more on near work (p = 0.04), and 0.21 ± 1.31 h/day less on outdoor leisure (p = 0.02), than they did at baseline. In the multivariate analysis, the younger among the secondary students (ß = 0.06, p < 0.001), and those with more near work hours at baseline (ß = -0.028, p = 0.033), exhibited more myopic refractive change. However, myopic refractive change was not found to be significantly associated with near work hours in the primary students, or with time spent outdoors, in either school level. After stratifying the activity hours into quartile groups, students with a greater near work load at baseline (trend P = 0.03) exhibited a greater myopic refractive change and had a higher risk to develop myopia (hazard ratio, 95 % confidence interval: 5.19, 1.49-18.13), after adjusting for the confounders. However, no significant association was found related to outdoor activity. CONCLUSIONS: In this cohort, children with a greater near work load at baseline exhibited more myopic refractive change and were also more likely to develop myopia. The protective effect of outdoor activity on myopic refractive change was not observed.

Comparison of pupillary dynamics to light in the mild traumatic brain injury (mTBI) and normal populations.

PURPOSE: To determine if mTBI adversely affects the pupillary light reflex (PLR). METHODS: The PLR was evaluated in mTBI and compared to normal individuals under a range of test conditions. Nine pupil parameters (maximum, minimum and final pupil diameter, latency, amplitude and peak and average constriction and dilation velocities) and six stimulus conditions (dim pulse, dim step, bright pulse, bright step, bright red step and bright blue step) were assessed in 32 adults with mTBI (21-60 years of age) and compared to 40 normal (22-56 years of age). The Neuroptics, infrared, DP-2000 binocular pupillometer was used (30 Hz sampling rate; 0.05 mm resolution) with binocular stimulation and recording. RESULTS: Different test conditions allowed for discrimination of different parameters. For any of the given six test conditions, five-to-eight of the nine pupillary parameters were statistically different (p < 0.05) between the two diagnostic groups. The most promising parameters for diagnostic differentiation were constriction latency, all pupillary diameters, average constriction velocity and peak dilation velocity. CONCLUSIONS: MTBI adversely affects the PLR. This suggests an impairment of the autonomic nervous system. The findings suggest the potential for quantitative pupillary dynamics to serve as an objective mTBI biomarker.

Quantifying pupillary asymmetry through objective binocular pupillometry in the normal and mild traumatic brain injury (mTBI) populations.

INTRODUCTION: Little is known about human inter-ocular pupillary asymmetry (IOPA). Thus, the purpose of the present investigation was to assess objectively static and dynamic IOPA in normals and in individuals with mild traumatic brain injury (mTBI). METHODS: The pupillary light reflex (PLR) was assessed in an adult population of normals and in those with mTBI using the Neuroptics DP-2000 binocular pupillometer. Four stimulus conditions were used to optimize the assessment. Two aspects of the pupil were assessed: baseline diameter prior to light stimulation and the dynamic amplitude of constriction following light stimulation. RESULTS: There was no statistical difference in either the static or dynamic IOPA between the two groups. Thus, the data were combined for a better global parameter estimate. The mean average static IOPA was 0.26 mm (SD = ± 0.20 mm) or 4.17% (± 3.29%). The mean average dynamic IOPA was dependent on the light stimulus condition, with the average across all four test conditions being 0.11 mm (± 0.10 mm) or 1.84% (± 1.70%). DISCUSSION: The inter-ocular pupillary effects of mTBI appear to be symmetrical rather than asymmetrical in nature. The findings provide clinicians and researchers a useful quantitative guideline to assess normal vs abnormal static and dynamic inter-ocular pupillary asymmetry (IOPA) in these two populations.

Eye exercises of acupoints: their impact on myopia and visual symptoms in Chinese rural children.

BACKGROUND: Chinese traditional "eye exercises of acupoints" have been advocated as a compulsory measure to reduce visual symptoms, as well as to retard the development of refractive error, among Chinese students for decades. The exercises are comprised of a 5-min, bilateral eye acupoint self-massage. This study evaluated the possible effect of these eye exercises among Chinese rural students. METHODS: Eight hundred thirty-six students (437 males, 52.3 %), aged 10.6 ± 2.5 (range 6-17) years from the Handan Offspring Myopia Study (HOMS) who completed the eye exercises and vision questionnaire, the convergence insufficiency symptom survey (CISS) questionnaire, and had a cycloplegic refraction were included in this study. RESULTS: 121 (14.5 %) students (64 males, 52.9 %) performed the eye exercises of acupoints in school. The multiple odds ratio (OR) and 95 % confidence interval (CI) for those having a "serious attitude" towards performing the eye exercises (0.12, 0.03-0.49) demonstrated a protective effect for myopia, after adjusting for the children's age, gender, average parental refractive error, and the time spent on near work and outdoor activity. The more frequently, and the more seriously, the students performed the eye exercises each week, the less likely was their chance of being myopic (OR, 95 % CI: 0.17, 0.03-0.99), after adjusting for the same confounders. However, neither the "seriousness of attitude" of performing the eye exercises (multiple ß coefficients: -1.58, p = 0.23), nor other related aspects of these eye exercises, were found to be associated with the CISS score in this sample. CONCLUSIONS: The traditional eye exercises of acupoints appeared to have a modest protective effect on myopia among these Chinese rural students aged 6-17 years. However, no association between the eye exercises and near vision symptoms was found.

Objective Assessment of Eye Dominance Using the VEP: A Pilot Study.

OBJECTIVES: To develop a clinical protocol for the determination of eye dominance using an objective method (i.e., the visual evoked potential [VEP]), and furthermore to determine the correlation of these objective findings with clinical subjective tests of eye dominance to provide guidance in clinical monovision refractive correction. METHODS: The Diopsys NOVA-TR system was used to record the VEP amplitude and latency of 10 visually-normal, presbyopic, adult subjects aged 50 to 70 years ((Equation is included in full-text article.)=60, SEM=0.17 years). First, eye dominance was assessed in two ways: a sensory-based "sensitivity to blur task" and a motor-based "sighting task." Next, while monocularly defocused, subjects binocularly viewed a black-and-white checkerboard (20-min arc size), pattern-reversal stimulus under 7 different test conditions: (1) baseline, (2) dominant (DE) eye blurred +1 diopter (D), (3) nondominant (NDE) eye blurred +1 D, (4) DE +2 D, (5) NDE +2 D, (6) DE +3 D, and (7) NDE +3 D. RESULTS: Under nearly all conditions (22/24=92%), the amplitude and latency were significantly different from baseline with any amount of defocus (P<0.05). Monocular defocus decreased, and increased, the mean binocular VEP amplitude and latency, respectively. There were no significant differences in either the binocular VEP amplitude or latency values when comparing defocused dominant vs. nondominant eyes. CONCLUSIONS: Eye dominance type (i.e., sensory or motor) and status (i.e., DE or NDE) did not provide a differential effect with respect to the VEP findings. Thus, the VEP technique does not show promise as an objective adjunct in the fitting of monovision correction.

Evaluation of the SVOne: A Handheld, Smartphone-Based Autorefractor.

PURPOSE: The SVOne is a portable Hartmann-Shack wavefront aberrometer that can be attached to a smartphone to determine the refractive error of the eye objectively. The aim of the present study was to compare the findings of the SVOne with retinoscopy, subjective refraction, and two commercially available autorefractors (Topcon KR-1W and Righton Retinomax-3). METHODS: Refractive error was assessed both with and without cycloplegia in 50 visually normal, young adults using the five techniques described above. Further, to assess repeatability of the instruments, the entire procedure was repeated in a subgroup of 10 subjects. All data were analyzed in terms of power vectors (M, J0, and J45). RESULTS: No significant difference was observed between the mean values of M (spherical equivalent) for the different techniques. However, a significantly higher mean value of precyclopegic J0 was recorded for the SVOne, which also had the highest limits of agreement for both the J0 and J45 astigmatic components. Retinoscopy and subjective refraction showed the best repeatability (in terms of M values) for precycloplegic and postcycloplegic measurements, respectively. High and significant linear correlations were observed between the subjective findings and the other four techniques. CONCLUSIONS: The results indicate that the SVOne handheld aberrometer provides measurements of refractive error in normal, young individuals that are not significantly different from other subjective and objective procedures. This instrument is valuable for vision screenings, as well as examinations taking place outside the clinical office. It may also serve as an adjunct in the standard optometric examination.

Short-term persistence of oculomotor rehabilitative changes in mild traumatic brain injury (mTBI): A pilot study of clinical effects.

PRIMARY OBJECTIVE: In our earlier published studies, oculomotor therapy (OMT) was performed in 15 individuals with mild traumatic brain injury (mTBI) and over 90% of the clinical oculomotor parameters abnormal at baseline significantly improved immediately following the OMT. There was no placebo (P) effect on any of the parameters. The purpose of the present pilot study was to assess the short-term persistence of the previously obtained positive OMT findings. RESEARCH DESIGN: Upon completion of the OMT, clinical oculomotor parameters were re-assessed at 3-month and 6-month periods. No subsequent training was performed during this 6-month period. METHODS AND PROCEDURES: Clinical measures were repeated in eight of the 15 subjects who subsequently completed both the 3-month and 6-month follow-up assessments. All measures were assessed using conventional clinical testing methods. MAIN OUTCOMES AND RESULTS: Eight of the 13 (62%) clinical oculomotor parameters exhibited either persistence of, or delayed, improvement at the 3 and 6 month follow-up intervals. CONCLUSIONS: Findings demonstrate both the presence and persistence of oculomotor-based changes, suggestive of neural plasticity even in the adult, compromised brain. Further studies are warranted to confirm and extend the present pilot findings.

Pupillary responses to light in chronic non-blast-induced mTBI.

PURPOSE: To evaluate objectively and quantitatively human pupillary responses to a light stimulus under photopic conditions in individuals with non-blast-induced, chronic, mild traumatic brain injury (mTBI). METHODS: Seventeen individuals with chronic, non-blast-induced mTBI and 15 visually-normal (VN) controls were tested (aged 21-45 years). Pupillary responsivity to a brief step-input light stimulus was assessed objectively in each eye for 5 seconds using the Neuroptics PLR-200 monocular, hand-held pupillometer with its pre-set and automated eight parameter analysis. RESULTS: Five of the eight parameters assessed were significantly reduced (p ≤ 0.05) in the mTBI group as compared to the VN control group: maximum (or peak) constriction velocity, average constriction velocity, average dilation velocity, maximum diameter and amplitude of constriction. The remaining three parameters were similar in each group (p > 0.05): constriction latency, 75% dilation recovery time and minimum diameter. CONCLUSIONS: The slowed dilation dynamics and reduced maximum pupillary diameter in mTBI suggest deficiency primarily of the sympathetic control system. The reduced peak velocities and related amplitudes suggest subtle parasympathetic involvement.

Objective assessment of visual attention in mild traumatic brain injury (mTBI) using visual-evoked potentials (VEP).

PURPOSE: To quantify visual attention objectively using the visual-evoked potential (VEP) in those having mild traumatic brain injury (mTBI) with and without a self-reported attentional deficit. RESEARCH DESIGN AND METHODS: Subjects were comprised of 16 adults with mTBI: 11 with an attentional deficit and five without. Three test conditions were used to assess the visual attentional state to quantify objectively the VEP alpha band attenuation ratio (AR) related to attention: (1) pattern VEP; (2) eyes-closed; and (3) eyes-closed number counting. The AR was calculated for both the individual and combined alpha frequencies (8-13 Hz). The objective results were compared to two subjective tests of visual and general attention (i.e. the VSAT and ASRS, respectively). RESULTS: The AR for both the individual and combined alpha frequencies was found to be abnormal in those with mTBI having an attentional deficit. In contrast, the AR was normal in those with mTBI but without an attentional deficit. The AR correlated with the ASRS, but not with the VSAT, test scores. CONCLUSIONS: The objective and subjective tests were able to differentiate between those having mTBI with and without an attentional deficit. The proposed VEP protocol can be used in the clinic to detect and assess objectively and reliably a visual attentional deficit in the mTBI population.

Effect of luminance on the visually-evoked potential in visually-normal individuals and in mTBI/concussion.

PURPOSE: To assess quantitatively the effect of luminance on VEP amplitude and latency in visually-normals (VN) and patients with mild traumatic brain injury (mTBI). METHODS: VN individuals (n = 20) and those with mTBI (n = 19) participated. Those with mTBI were assessed 1-10 years post-injury (mean = 4.97 years), with the exception of one subject. Pattern VEP testing was employed using the DIOPSYS™ NOVA-TR system, with a 74 cd m-2 baseline luminance. Luminance levels were reduced with five different neutral density (ND) filters (0.5, 1.0, 1.5, 2.0 and 2.5) and compared to the baseline response. All testing was performed under binocular-viewing conditions with full refractive correction in place. RESULTS: In both groups, mean VEP amplitude reduced with decrease in luminance (p < 0.05). At each luminance level, the mean VEP amplitude was significantly lower in mTBI than in the VN population (p < 0.05). In both groups, the mean VEP latency increased progressively with reduction in luminance (p < 0.05), with it being significantly higher in mTBI than in the VN population (p < 0.05). CONCLUSIONS: High luminance levels produced an optimal VEP response in both populations. VEP amplitude was robust, whereas latency progressively increased in both groups as luminance decreased. The latency increase with decreased luminance was significantly larger in those with mTBI, thus suggesting that latency can be used to differentiate reliably between VN individuals and those with mTBI.

Near work, outdoor activity, and their association with refractive error.

PURPOSE: To assess the relationship between near work, outdoor activity, and refractive error in schoolchildren in Beijing. METHODS: The Beijing Myopia Progression Study is a hospital-based myopia study, in which 386 students from primary (aged 6 to 12 years) and secondary (aged 13 to 17 years) schools in the inner city of Beijing were enrolled. Cycloplegic refraction and a detailed questionnaire probing near, intermediate, and distance visual activities were completed. RESULTS: Three hundred seventy (95.9%) of 386 students with complete cycloplegic autorefraction and myopia questionnaire data were enrolled in this study. Children with more near work time did not exhibit a significantly more myopic refraction in both the primary and secondary school levels after adjusting for the children's gender, outdoor activity time, and average parental refractive error. A significant association between outdoor activity time (in hours per day) and the children's spherical equivalent (in diopters) was found in the primary school students (ß = 0.27, p = 0.03) but not in the secondary school students (ß = 0.04, p = 0.70) after adjusting for similar confounders. The time spent on outdoor sports and outdoor leisure in the primary school students was also significantly associated with the children's spherical equivalent (ß = 0.46, p = 0.04 and ß = 0.31, p = 0.02, respectively). Primary school students with more time outdoors exhibited relatively less myopic refraction than their peers (ptrend = 0.0003), but this relation was not demonstrated in the secondary school children (ptrend = 0.53) after adjusting for similar confounders. CONCLUSIONS: Higher levels of outdoor activity were associated with less myopic refraction in primary school students in the inner city of Beijing. Near work activity was not found to be associated with refraction at either school level.

Versional eye tracking in mild traumatic brain injury (mTBI): effects of oculomotor training (OMT).

OBJECTIVE: To evaluate a range of objective measures of versional eye movements before and after oculomotor training (OMT) in individuals with mTBI. The results were compared with placebo (P) training. METHODS: Twelve individuals with mTBI (mean age = 29 ± 3 years) having oculomotor-based near-vision symptoms participated in the study. Versional eye movements were recorded objectively before and after OMT (fixation, predictable saccades, simulated reading) and P training (6 weeks each, two sessions/week, 45 minutes/session). RESULTS: Following OMT, there was a significant (p < 0.05) reduction in the horizontal fixational error. Saccadic gain increased both horizontally and vertically (p < 0.05). The saccade ratio for the simulated reading, multiple-line paradigm reduced significantly (p < 0.05). None of the measures changed significantly following the P training. CONCLUSIONS: The versional-based OMT had a significant, positive effect on most aspects of versional tracking. These findings are suggestive of improved rhythmicity, accuracy and sequencing of saccades following OMT in mTBI as a result of oculomotor learning.

Effect of binasal occlusion (BNO) and base-in prisms on the visual-evoked potential (VEP) in mild traumatic brain injury (mTBI).

PURPOSE: To assess quantitatively the effect and relative contribution of binasal occlusion (BNO) and base-in prisms (BI) on visually-evoked potential (VEP) responsivity in persons with mild traumatic brain injury (mTBI) and the symptom of visual motion sensitivity (VMS), as well as in visually-normal (VN) individuals. RESEARCH DESIGN AND METHODS: Subjects were comprised of 20 VN adults and 15 adults with mTBI and VMS. There were four test conditions: (1) conventional pattern VEP, which served as the baseline comparison condition; (2) VEP with BNO alone; (3) VEP with 2 pd BI prisms before each eye; and (4) VEP with the above BNO and BI prism combination. RESULTS: In mTBI, the mean VEP amplitude increased significantly in nearly all subjects (∼90%) with BNO alone. In contrast, in VN, it decreased significantly with BNO alone in all subjects (100%), as compared to the other test conditions. These objective findings were consistent with improvements in visual impressions and sensorimotor tasks in the group with mTBI. Latency remained within normal limits under all test conditions in both groups. CONCLUSIONS: Only the BNO condition demonstrated significant, but opposite and consistent, directional effects on the VEP amplitude in both groups. The BNO-VEP test condition may be used clinically for the objectively-based, differential diagnosis of persons suspected of having mTBI and VMS from the VNs.