By means of continuous visual stimulation to simulate the motion-in-depth course where object was approaching to observer gradually, we studied the event-related potentials (ERP) response in that course. This article was directed to the effect of object size factor on the ERP of motion-in-depth perception. The subjects recruited were 9 health men, aged 22-29 years. The results illustrated that, in motion-in-depth course, the main components were P80, N100, P140, N220, P300, N350, and P400. They mainly appeared in the frontal area, occipital area and occipital-parietal area; some of them showed near by the parietal-temporal or occipital-temporal area. Among these components, N220 was most closely related to the perception of motion-in-depth. From the data analysis in 500 ms, bigger object led to earlier and stronger response.
Adult ; Cognition ; physiology ; Depth Perception ; physiology ; Electroencephalography ; Evoked Potentials ; physiology ; Humans ; Male ; Motion Perception ; physiology ; Photic Stimulation ; methods ; Young Adult

In this study, we explored the neural mechanism underlying impaired stereopsis and possible functional plasticity after strabismus surgery. We enrolled 18 stereo-deficient patients with intermittent exotropia before and after surgery, along with 18 healthy controls. Functional magnetic resonance imaging data were collected when participants viewed three-dimensional stimuli. Compared with controls, preoperative patients showed hypoactivation in higher-level dorsal (visual and parietal) areas and ventral visual areas. Pre- and postoperative activation did not significantly differ in patients overall; patients with improved stereopsis showed stronger postoperative activation than preoperative activation in the right V3A and left intraparietal sulcus. Worse stereopsis and fusional control were correlated with preoperative hypoactivation, suggesting that cortical deficits along the two streams might reflect impaired stereopsis in intermittent exotropia. The correlation between improved stereopsis and activation in the right V3A after surgery indicates that functional plasticity may underlie the improvement of stereopsis. Thus, additional postoperative strategies are needed to promote functional plasticity and enhance the recovery of stereopsis.
Humans ; Exotropia/surgery* ; Depth Perception/physiology* ; Strabismus/surgery* ; Oculomotor Muscles/surgery*

PURPOSE: Stereopsis in normal subjects aged between 7 and 76 years was compared to examine changes in stereopsis with age. METHODS: Eighty subjects with no ocular disease were divided into 8 groups by age. Near stereopsis was evaluated with the TNO, Titmus, and Randot tests; distance stereopsis with the Mentor B-VAT II video acuity tester. RESULTS: The results of all 4 tests showed decreased stereopsis with increasing age (p< 0.05). Compared to the stereoacuity of 7 to 10-year-old group, both the TNO and distance stereopsis test results were significantly decreased for the 6th, 7th, and 8th decade groups, while both the Titmus and Randot test results were significantly decreased for the 8th decade group (p< 0.05). CONCLUSIONS: Overall, both near and distance stereopsis decreased with increasing age. Thus, decreased stereopsis should be taken into account when performing the stereopsis test.
Adolescent ; Adult ; Aged ; Aging/*physiology ; Child ; Depth Perception/*physiology ; Female ; Humans ; Male ; Middle Aged ; Reference Values ; Visual Acuity/*physiology

BACKGROUNDScreening for amblyopia at earliest is important for early treatment and better prognosis. This study aimed to evaluate the validity of uncorrected distant and near visual acuity (VA) and stereoacuity for screening amblyopia in grade-1 students in primary school in central China.

METHODSBy stratified cluster sampling, 3112 grade-1 students from 11 Anyang primary schools were selected for the study. All the participants underwent uncorrected distant and near VA, stereopsis test, cycloplegic refraction, best corrected VA (BCVA), cover test, and ocular movement examination. VA was measured with a logarithm of the minimum angle of resolution (logMAR) chart. Stereoacuity was measured with the Lang II stereo card and TNO test. Amblyopia was defined as the BCVA less than or equal to 0.1 logMAR units of any eye in the absence of significant pathological abnormalities. The sensitivity, specificity, and positive and negative predictive value of uncorrected VA and stereoacuity for amblyopia were analyzed.

RESULTSOut of the 3112 eligible students, 2893 (92.96%) completed the examinations. The average age of the students was (7.10 ± 0.41) years. Screened by distant VA with low cutoff (logMAR 0.1), high cutoff (logMAR 0.0), and near VA (logMAR 0.0), 31.64%, 73.18%, and 50.23% students were abnormal, respectively. Screened by stereopsis test, only 4.69% students were abnormal. Diagnosed by a senior pediatric ophthalmologist, 61 students had amblyopia. The sensitivities of distant VA with low/high cutoff and near VA were 92.31%, 100%, and 80.77%, respectively, whereas that of stereoacuity by TNO test was 15.38%. Simultaneous testing of either two of the three tests improved the sensitivity.

CONCLUSIONSDistant VA test of high cutoff alone displays a high sensitivity but a low specificity. Simultaneous testing of distant VA of low cutoff and stereoacuity is a better choice to balance between sensitivity and specificity.

Amblyopia ; diagnosis ; physiopathology ; Child ; Child, Preschool ; China ; Depth Perception ; Female ; Humans ; Male ; Schools ; Vision Screening ; Visual Acuity ; physiology

PURPOSE: To evaluate the effect of acrylic refractive prism and Fresnel membrane prism on stereoacuity in intermittent exotropia. MATERIALS AND METHODS: Stereoacuities of fifty-two patients (mean age, 12.4 years; range 6 to 45 years) with intermittent exotropia were measured using the Titmus and TNO stereotests, while they wore prisms of varying power on nonfixating eye or evenly on each eye. RESULTS: Stereoacuities were significantly reduced with increasing prism power for both prisms, ranging from 8 to 25 prism dipotres. The effects on stereoacuity in single acrylic prism and single Fresnel prism were similar, whereas spilt Fresnel prisms reduced stereoacuity more than spilt acrylic prisms. Spilt prisms were found to have much less effect on stereoacuity than single prisms for both acrylic and Fresnel prisms. CONCLUSION: The use of acrylic refractive prism shared evenly on each eye would be optimal method to minimize the reduction of stereoacuity during the prismatic therapy for intermittent exotropia.
Adolescent ; Adult ; Child ; Depth Perception/*physiology ; Exotropia/physiopathology/*therapy ; *Eyeglasses ; Female ; Humans ; Male ; Refraction, Ocular/physiology ; Visual Acuity/*physiology ; Young Adult

PURPOSE: To investigate the effect of watching 3-dimensional (3D) television (TV) on refractive error in children. METHODS: Sixty healthy volunteers, aged 6 to 12 years, without any ocular abnormalities other than refractive error were recruited for this study. They watched 3D TV for 50 minutes at a viewing distance of 2.8 meters. The image disparity of the 3D contents was from -1 to 1 degree. Refractive errors were measured both before and immediately after watching TV and were rechecked after a 10-minute rest period. The refractive errors before and after watching TV were compared. The amount of refractive change was also compared between myopes and controls. The refractive error of the participants who showed a myopic shift immediately after watching TV were compared across each time point to assure that the myopic shift persisted after a 10-minute rest. RESULTS: The mean age of the participants was 9.23 ± 1.75 years. The baseline manifest refractive error was -1.70 ± 1.79 (-5.50 to +1.25) diopters. The refractive errors immediately after watching and after a 10-minute rest were -1.75 ± 1.85 and -1.69 ± 1.80 diopters, respectively, which were not different from the baseline values. Myopic participants (34 participants), whose spherical equivalent was worse than -0.75 diopters, also did not show any significant refractive change after watching 3D TV. A myopic shift was observed in 31 participants with a mean score of 0.29 ± 0.23 diopters, which resolved after a 10-minute rest. CONCLUSIONS: Watching properly made 3D content on a 3D TV for 50 minutes with a 10-minute intermission at more than 2.8 meters of viewing distance did not affect the refractive error of children.
Accommodation, Ocular/*physiology ; Child ; Depth Perception/*physiology ; Disease Progression ; Female ; Humans ; Imaging, Three-Dimensional/*adverse effects ; Male ; Refractive Errors/*physiopathology ; *Television ; Vision, Binocular/*physiology

PURPOSE: To investigate the association between binocular function and vision after cataract removal and primary posterior chamber intraocular lens (PC-IOL) implantation in children with unilateral cataract and to identify visual function differences according cataract type. METHODS: Clinical records of 2- to 6-year-old patients with unilateral cataract removal and primary PC-IOL implantation were reviewed retrospectively. Visual acuity and ocular alignment were measured. Sensory fusion was assessed with the Worth 4-dot test, and stereoacuity with the Titmus stereo test. Cataracts were classified according to cause, lens opacity location, age at onset, and presence of strabismus. Clinical characteristics of patients who obtained good visual function were identified. RESULTS: Forty-seven patients were included. Among 22 (46.8%) with good vision (20/40 or better), only 6 (27.3%) achieved good binocular function (the presence of fusion and 100 seconds of arc or better of stereoacuity). Visual acuity was better in eyes with good binocular function (p=0.002). No other variables were significant for achieving good binocular function. CONCLUSIONS: The removal of unilateral cataract in a visually immature child can result in a combination of good visual acuity and binocular function. Good binocular function is closely related to good visual acuity.
Cataract/genetics/pathology ; Cataract Extraction/*methods ; Child, Preschool ; Depth Perception/*physiology ; Female ; Follow-Up Studies ; Humans ; Infant ; Infant, Newborn ; Lens Implantation, Intraocular/*methods ; Male ; Postoperative Period ; Retrospective Studies ; Treatment Outcome ; Visual Acuity/*physiology

Existing methods of stereoacuity testing need specific glasses or optical device for use. We have designed a new stereoacuity test for the digitalized, random-dot stereogram and researched its clinical usefulness. A digitalized, random-dot, stereoacuity test card was created with a computer program that used a preferred symbol and the designed system was tested along with the Randot preschool stereoacuity, Titmus-fly and Lang tests to compare their sensitivity and specificity. The mean success rate of the digitalized, random-dot test was 98.2%, while the rates of the Randot preschool stereoacuity, Titmus-fly and Lang tests were 89.3%, 74.2% and 86.1%, respectively. Sensitivity and specificity of the new test were 100% and 95.3%, respectively, which were not that different from those of the Randot preschool stereoacuity, Titmus-fly and Lang tests. We found that the digitalized, random-dot, stereoacuity test has a high success rate and can be appropriately used in medical examinations and follow-up tests for strabismus patients.
Age Distribution ; Child, Preschool ; Comparative Study ; Computer Graphics ; Depth Perception/*physiology ; Female ; Humans ; Male ; Reproducibility of Results ; Research Support, Non-U.S. Gov't ; Sensitivity and Specificity ; Software ; Vision Disorders/*diagnosis ; Vision Tests/*instrumentation/methods ; Vision, Binocular

PURPOSE: To investigate horizontal image disparity in three-dimensional (3-D) perception using 3-D animations in normal control patients and patients with intermittent exotropia, anisometropic amblyopia, and partially accommodative esotropia. MATERIALS AND METHODS: A total of 133 subjects were included. Stereopsis was measured using the Titmus Stereo test (Stereo Optical Inc., Chicago, IL, USA) and a 3-D stereopsis test with a 15 inch 3-D display laptop, adjusting 3-D parameters of 0 mm horizontal disparity to 15 mm horizontal disparity. RESULTS: When compared with normal controls, the average threshold of the 3-D stereopsis test was significantly reduced for esotropia patients (p<0.001) and for anisometric amblyopia patients (p<0.001), compared to normal controls. No significant difference was observed between normal controls and intermittent exotropia patients (p=0.082). The 3-D stereopsis test was correlated with the Titmus Stereo test (Spearman's rho=0.690, p<0.001). Mean difference in stereoacuity was 1.323 log seconds of arc (95% limits of agreement: 0.486 to 2.112), and 125 (92.5%) patients were within the limits of agreement. CONCLUSION: This study demonstrated that a 3-D stereopsis test with animation is highly correlated with the Titmus Stereo test; nevertheless, 3-D stereopsis with animations generates more image disparities than the conventional Titmus Stereo test. The 3-D stereopsis test is highly predictive for estimating real stereopsis in a 3-D movie theater.
Adult ; Aged ; Amblyopia/diagnosis ; Anisometropia/diagnosis ; *Depth Perception ; Esotropia/diagnosis ; Female ; Humans ; Imaging, Three-Dimensional/*instrumentation ; Male ; Middle Aged ; *Perceptual Disorders ; Software ; *Vision Disparity ; Vision, Binocular ; Visual Acuity/*physiology