OBJECTIVES: To study the virtual reality-pattern visual evoked potential (VR-PVEP) P100 waveform characteristics of monocular visual impairment with different impaired degrees under simultaneous binocular perception and monocular stimulations. METHODS: A total of 55 young volunteers with normal vision (using decimal recording method, far vision ≥0.8 and near vision ≥0.5) were selected to simulate three groups of monocular refractive visual impairment by interpolation method. The sum of near and far vision ≤0.2 was Group A, the severe visual impairment group; the sum of near and far vision <0.8 was Group B, the moderate visual impairment group; and the sum of near and far vision ≥0.8 was Group C, the mild visual impairment group. The volunteers' binocular normal visions were set as the control group. The VR-PVEP P100 peak times measured by simultaneous binocular perception and monocular stimulation were compared at four spatial frequencies 16×16, 24×24, 32×32 and 64×64. RESULTS: In Group A, the differences between P100 peak times of simulant visual impairment eyes and simultaneous binocular perception at 24×24, 32×32 and 64×64 spatial frequencies were statistically significant (P<0.05); and the P100 peak time of normal vision eyes at 64×64 spatial frequency was significantly different from the simulant visual impairment eyes (P<0.05). In Group B, the differences between P100 peak times of simulant visual impairment eyes and simultaneous binocular perception at 16×16, 24×24 and 64×64 spatial frequencies were statistically significant (P<0.05); and the P100 peak time of normal vision eyes at 64×64 spatial frequency was significantly different from the simulant visual impairment eyes (P<0.05). In Group C, there was no significant difference between P100 peak times of simulant visual impairment eyes and simultaneous binocular perception at all spatial frequencies (P>0.05). There was no significant difference in the P100 peak times measured at all spatial frequencies between simulant visual impairment eyes and simultaneous binocular perception in the control group (P>0.05). CONCLUSIONS VR-PVEP can be used for visual acuity evaluation of patients with severe and moderate monocular visual impairment, which can reflect the visual impairment degree caused by ametropia. VR-PVEP has application value in the objective evaluation of visual function and forensic clinical identification.
Humans ; Evoked Potentials, Visual ; Vision, Ocular ; Vision, Binocular/physiology* ; Vision Disorders/diagnosis* ; Virtual Reality

Aiming at the medical service robot used in the indoor environment, this study proposes a method to test the pose accuracy of its working surface based on the binocular vision system. This method uses a binocular vision coordinate system to measure targets fixed on the working surface of the service robot, aligns the measurement system with the robot base coordinate system through the nonlinear least squares method, and integrates the multi-eye image data to achieve the accuracy test of the working surface. Finally, the vision test program was tested and verified on a mobile service robot model ABIR X8. According to the accuracy index given in GB/T 38124 Service Robot Performance Test Method, the test results of its pose accuracy were obtained.
Optical Devices ; Robotics ; Vision, Binocular

In robot-assisted eye surgery, such as retinal vascular bypass surgery, precise positioning of operating points is required. In this study, a binocular vision-based 3D reconstruction method is proposed to locate the incision points on retinal vessels. Vessels in the image were extracted by CLAHE algorithm to remove the influence of background, then stereo matching was performed. Finally, the retinal vessel image was reconstructed by using the principle of parallax in binocular vision. Experimental results show that this method can accurately locate the incision points on retinal vessels and meet the requirements of ophthalmic surgery.
Algorithms ; Humans ; Imaging, Three-Dimensional ; Ophthalmologic Surgical Procedures ; Retinal Vessels/diagnostic imaging* ; Robotic Surgical Procedures ; Vision, Binocular

Strabismus is a pathologic condition in which the eyes do not properly align with each other forming different images on the corresponding retinal points. Early diagnosis and appropriate management of strabismus in the sensitive period of visual maturation is critical for the development of normal binocular vision in children. Therefore, it is important to perform ophthalmologic examinations including cycloplegic refraction and ocular alignment as early as possible to detect risk factors for amblyopia and strabismus. Strabismus could also be a sign of intraocular pathology, brain diseases or myasthenia gravis which may require urgent treatment. Strabismus can be treated by surgical and non-surgical methods. The first step in the management of strabismus is to correct amblyogenic refractive errors and prescribe glasses if necessary. Bifocal lenses, prism glasses, occlusion therapy, and botulinum toxin injection could also be considered. Surgery is usually performed if non-surgical treatments are unsuccessful. Making an accurate diagnosis and setting practical goals and limitations of treatment is the key to success in the treatment of strabismus.
Amblyopia ; Botulinum Toxins ; Brain Diseases ; Child ; Diagnosis ; Early Diagnosis ; Eyeglasses ; Glass ; Humans ; Myasthenia Gravis ; Pathology ; Refractive Errors ; Retinaldehyde ; Risk Factors ; Strabismus ; Vision, Binocular

PURPOSE: To investigate the long-term clinical course of intermittent exotropia after surgical treatment to determine whether and when postoperative exo-drift stabilizes, and the required postsurgery follow-up duration in cases of intermittent exotropia. METHODS: We retrospectively reviewed the medical records of patients diagnosed with intermittent exotropia who underwent surgical treatment between January 1992 and January 2006 at Yeungnam University Hospital and postoperatively performed regular follow-up examinations for up to 7 years. We also analyzed the difference in exo-drift stabilization, according to surgical procedure. RESULTS: A total of 101 patients were enrolled in the study. Thirty-one patients underwent lateral rectus recession and medial rectus resection (R&R) and 70 patients underwent bilateral lateral rectus recession (BLR). The postoperative angles of deviation increased significantly during the initial 36 months, but no subsequent significant changes were observed for up to 84 months. Follow-ups for 7 years revealed that more than 50% of the total amount of exo-drift was observed within the first postoperative year. In addition, the angles of deviation at 1 year correlated with those at 7 years postoperatively (Pearson correlation coefficient r = 0.517, p < 0.001). No significant exo-drift was observed after 36 months in patients who underwent BLR, whereas after 18 months in patients who underwent R&R. CONCLUSIONS: The minimum postoperative follow-up required after surgical treatment to ensure stable results is 36 months. In particular, careful follow-up is necessary during the first postoperative year to detect rapid exo-drift. Patients who underwent BLR required a longer follow-up than those who underwent R&R to ensure stable postoperative alignment.
Child ; Child, Preschool ; Exotropia/*physiopathology/surgery ; Female ; Follow-Up Studies ; Humans ; Male ; Oculomotor Muscles/*physiopathology/surgery ; *Ophthalmologic Surgical Procedures ; Postoperative Complications/*physiopathology ; Retrospective Studies ; Vision, Binocular/physiology ; Visual Acuity/physiology

PURPOSE: To compare postoperative exodrift of the first unilateral lateral rectus (ULR) muscle recession with the exodrift of the second contralateral ULR muscle recession in patients with recurrent small-angle exotropia (XT). METHODS: We evaluated the results of a second ULR muscle recession in 19 patients with recurrent XT with deviation angles under 25 prism diopter (PD), following a first procedure of ULR muscle recession for small-angle XT. Recession of the lateral rectus muscle ranged from 8 to 9 mm. The postoperative motor alignment and degree of exodrift were investigated after the first ULR muscle recession and the second ULR muscle recession in the same patients. RESULTS: Observed differences in postoperative ocular alignment between the first ULR muscle recession and the second ULR muscle recession were statistically significant at follow-up periods of six months (7.84 +/- 4.43 vs. 3.89 +/- 3.47 PD), one year (9.58 +/- 4.97 vs. 5.21 +/- 4.94 PD), and at a final follow-up (21.11 +/- 2.98 vs. 7.52 +/- 4.06 PD) after surgery (p = 0.006, 0.013, and 0.000). Postoperative exodrift was statistically different between the first and second ULR muscle recessions at three to six months (2.89 +/-3.75 vs. 0.63 +/- 3.45 PD) and one year to final follow-up (11.52 +/- 5.50 vs. 2.32 +/- 3.53 PD) (p = 0.034 and 0.000). All of the first ULR muscle recession patients showed XT with deviation angles of more than 15 PD at the final follow-up. Regardless, the surgical success rate (<8 PD) after the second ULR recession was 63.16% (12 patients) among the total amount of patients with recurrent XT. CONCLUSIONS: This study shows that changes in exodrift after a second ULR muscle recession are less than changes after the first URL muscle recession among patients with recurrent XT. A second ULR muscle recession may be a useful surgery for small-angle XT patients with deviation angles of 25 PD or less after a first ULR muscle recession.
Child ; Child, Preschool ; *Exotropia/etiology/physiopathology/surgery ; Female ; Follow-Up Studies ; Humans ; Male ; Oculomotor Muscles/physiopathology/*surgery ; *Ophthalmologic Surgical Procedures ; *Postoperative Complications ; Recurrence ; Retrospective Studies ; Vision, Binocular/physiology

PURPOSE: To report a case of tamoxifen-induced retinopathy diagnosed using spectral domain optical coherence tomography (SD-OCT). CASE SUMMARY: A 44-year-old female presented with metamorphopsia in the left eye and binocular vision loss which started 5 months prior. She had no record of external trauma, diabetes or high blood pressure; however, she had been taking 21.9 g tamoxifen (20 mg/day) since October 2012 after a surgery of her left breast due to cancer. On the initial visit, fundus photography showed crystalline dot-like deposits in both parafoveae. Additionally, fluorescence angiography revealed a small leakage around the macular area. Optical coherence tomography (OCT) was obtained to differentiate from other diseases because fundus photography showed crystalline retinopathy. The OCT revealed a normal right eye but the left macula had a microcystic lesion. Based on the diagnosis of tamoxifen-induced retinopathy, the patient stopped taking tamoxifen. Three months after discontinuation of tamoxifen, fundus photography showed slightly decreased crystalline deposits in the parafoveal area and visual acuity of the right eye was slightly improved. However, SD-OCT showed a slightly aggravated disruption of the outer retina in both eyes. CONCLUSIONS: Although retinopathy caused by treatment with tamoxifen occurs infrequently, to prevent complications and irreversible damage, patients who take tamoxifen for medical purposes need to undergo a regular ophthalmologic examination.
Adult ; Breast ; Crystallins ; Diagnosis ; Female ; Fluorescein Angiography ; Humans ; Hypertension ; Photography ; Retina ; Tamoxifen ; Tomography, Optical Coherence* ; Vision Disorders ; Vision, Binocular ; Visual Acuity

PURPOSE: The purpose of this study is to compare the magnitude and axis of astigmatism induced by a combined inferior oblique (IO) anterior transposition procedure with lateral rectus (LR) recession versus LR recession alone. METHODS: Forty-six patients were retrospectively analyzed. The subjects were divided into two groups: those having concurrent inferior oblique muscle overaction (IOOA) and intermittent exotropia (group 1, 20 patients) and those having only intermittent exotropia as a control (group 2, 26 patients). Group 1 underwent combined anterior transposition of IO with LR recession and group 2 underwent LR recession alone. Induced astigmatism was defined as the difference between preoperative and postoperative astigmatism using double-angle vector analysis. Cylinder power, axis of induced astigmatism, and spherical equivalent were analyzed at 1 week, 1 month, and 3 months after surgery. RESULTS: Larger changes in the axis of induced astigmatism were observed in group 1, with 4.5° incyclotorsion, than in group 2 at 1 week after surgery (axis, 84.5° vs. 91°; p < 0.001). However, there was no statistically significant inter-group difference thereafter. Relaxation and rapid regression in the incyclotorsion of induced astigmatism were observed over-time. Spherical equivalent significantly decreased postoperatively at 1 month in both groups, indicating a myopic shift (p = 0.011 for group 1 and p = 0.019 for group 2) but did not show significant differences at 3 months after surgery (p = 0.107 for group 1 and p = 0.760 for group 2). CONCLUSIONS: Combined IO anterior transposition procedures caused an increased change in the axis of induced astigmatism, including temporary incyclotorsion, during the first week after surgery. However, this significant difference was not maintained thereafter. Thus, combined IO surgery with LR recession does not seem to produce a sustained astigmatic change, which can be a potential risk factor of postoperative amblyopia or diplopia compared with LR recession alone.
Astigmatism/diagnosis/*etiology/physiopathology ; Child ; Exotropia/diagnosis/physiopathology/*surgery ; Eye Movements/*physiology ; Female ; Follow-Up Studies ; Humans ; Male ; Oculomotor Muscles/*surgery ; Ophthalmologic Surgical Procedures/*methods ; Retrospective Studies ; Treatment Outcome ; Vision, Binocular/*physiology

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: The purpose of this study is to compare the surgical outcomes and near stereoacuities after unilateral medial rectus (MR) muscle resection and lateral rectus (LR) recession according to deviation angle in basic intermittent exotropia, X(T). METHODS: Ninety patients with basic type X(T) were included in this study. They underwent unilateral recession of the LR and resection of the MR and were followed postoperatively for at least 12 months. Patients were divided into three groups according to their preoperative deviation angle: group 1 < or =20 prism diopter (PD), 20 PD< group 2 <40 PD, and group 3 > or =40 PD. Surgical outcomes and near stereoacuities one year after surgery were evaluated. Surgical success was defined as having a deviation angle range within +/-10 PD for both near and distance fixation. RESULTS: Among 90 patients, groups 1, 2, and 3 included 30 patients each. The mean age in groups 1, 2, and 3 was 9.4 years, 9.4 years, and 11.0 years, respectively. The surgical success rates one year after surgery for groups 1, 2, and 3 were 80.0%, 73.3%, and 73.3% (chi-square test, p = 0.769), respectively. The undercorrection rates for groups 1, 2, and 3 were 16.7%, 23.3%, and 26.7%, and the overcorrection rates were 3.3%, 3.3%, and 0%, respectively. The mean preoperative near stereoacuities for groups 1, 2, and 3 were 224.3 arcsec, 302.0 arcsec, and 1,107.3 arcsec, and the mean postoperative near stereoacuities were 218.3 arcsec, 214.7 arcsec, and 743.0 arcsec (paired t-test; p = 0.858, p = 0.379, p = 0.083), respectively. CONCLUSIONS: In basic X(T) patients, the amount of angle deviation has no influence on surgical outcomes in unilateral LR recession and MR resection. The near stereoacuities by one year after LR recession and MR resection for intermittent X(T) were not different among patient groups separated by preoperative deviation angle.
Child ; Exotropia/physiopathology/*surgery ; Female ; Follow-Up Studies ; Humans ; Male ; Oculomotor Muscles/physiopathology/*surgery ; *Ophthalmologic Surgical Procedures ; Retrospective Studies ; Treatment Outcome ; Vision, Binocular/physiology ; Visual Acuity/physiology