Exposure to a high altitude hypoxia environment has significant negative effects on human central nervous system. Many previous studies have explored the influence of the high altitude environment on human color perception in a simulated high altitude environment or in an environment acutely exposed to high altitude, but little has been done in migrators and natives exposed to high altitude and low oxygen for a long period of time. In this study, the minimal-change method was used to examine whether the color perception of red, green, blue and yellow was affected by the high altitude in 30 plain residents, 30 Han migrators who have lived in the high altitude for 2 years, and 28 high-altitude-adapted Tibetan natives. The results showed that long-term high altitude exposure had the most significant effect on the blue and red color perception in the natives and the migrators, with the effect on the blue color being significantly greater than that on the red color. However, the effects on green color processing only happened to the natives. The results suggest that there is an internal correlation between blood supply and selectivity changes of visual color processing caused by exposure to the plateau environment.
Altitude ; China ; Color Perception ; physiology ; Humans ; Hypoxia ; Oxygen ; metabolism

PURPOSE: To analyze the effect of stereopsis and contrast sensitivity on the quality of life and to evaluate the relationship between integrated binocular visual field (IVF) and binocular visual function in bilateral normal tension glaucoma (NTG) patients. METHODS: Stereopsis and contrast sensitivity tests were performed and compared among 44 NTG patients and 32 normal subjects. The IVF was integrated using the best location method. The correlation between visual function and subscales of the National Eye Institute Visual Function Questionnaire 25 (NEI VFQ-25) was evaluated using univariate linear regression. RESULTS: Stereopsis and contrast sensitivity for the bilateral NTG patients were decreased compared to the normal controls. Stereopsis and contrast sensitivity exhibited a significant correlation with social functions related to vision and color vision among subscales of NEI VFQ-25. IVF mean deviation (MD) and better eye MD showed a significant correlation with stereopsis and contrast sensitivity, while worse eye MD showed no association. CONCLUSIONS: Deterioration of stereopsis and contrast sensitivity in NTG patients affects their quality of life related to social functions and color vision. Both IVF and better eye MDs are correlated with stereopsis and contrast sensitivity in NTG patients.
Color Vision ; Contrast Sensitivity ; Depth Perception ; Humans ; Linear Models ; Low Tension Glaucoma* ; Methods ; National Eye Institute (U.S.) ; Quality of Life* ; Telescopes* ; Visual Fields

PURPOSE: The purpose of this study was to compare the optical properties of pre-colored dental monolithic zirconia ceramics of various thicknesses sintered in a microwave and those in a conventional furnace. MATERIALS AND METHODS: A2-shade of pre-colored monolithic zirconia ceramic specimens (22.0 mm × 22.0 mm) in 3 thickness groups of 0.5, 1.0, and 1.5 mm were divided into 2 subgroups according to the sintering methods (n=9): microwave and conventional sintering. A spectrophotometer was used to obtain CIELab color coordinates, and translucency parameters and CIEDE2000 color differences (ΔE 00) were measured. The relative amount of monoclinic phase (X(m)) was estimated with x-ray diffraction. The surface topography was analyzed by atomic force microscope and scanning electron microscope. Statistical analyses were conducted with two-way ANOVA (α=.05). RESULTS: There were small interaction effects on CIE L*, a*, and TP between sintering method and thickness (P<.001): L* (partial eta squared η(p)²=0.115), a* (η(p)²=0.136), and TP (η(p)²=0.206), although higher b* values were noted for microwave sintering regardless of thickness. Color differences between two sintering methods ranged from 0.52 to 0.96 ΔE(00) units. The X(m) values ranged from 7.03% to 9.89% for conventional sintering, and from 7.31% to 9.17% for microwave sintering. The microwave-sintered specimen demonstrated a smoother surface and a more uniform grain structure compared to the conventionally-sintered specimen. CONCLUSION: With reduced processing time, microwave-sintered pre-colored dental monolithic zirconia ceramics can exhibit similar color perception and translucency to those by conventional sintering.
Ceramics* ; Clothing ; Color Perception ; Methods ; Microwaves* ; Spectrophotometry ; X-Ray Diffraction

PURPOSE: Our objective was to estimate the maximum color contrast sensitivity (MCCS) thresholds in individuals with chiasma opticum damage. METHODS: The pilot study tested 41 people with pituitary adenoma (PA) and 100 age- and gender-matched controls. Patients were divided into two groups according to PA size, PA ≤1 cm or PA >1 cm. A new MCCS test program was used for color discrimination. RESULTS: The mean total error score (TES) of MCCS was 1.8 in the PA ≤1 cm group (standard deviation [SD], 0.38), 3.5 in the PA >1 cm group (SD, 0.96), and 1.4 in the control group (SD, 0.31; p < 0.001). There was a positive correlation between tumor size and MCCS result (r = 0.648, p < 0.01). In the group that had PA-producing hormones, the TES was 2.5 (SD, 1.09), compared to 4.2 value in the non-functioning PA group of patients that did not have clinically significant hormone excess (SD, 3.16; p < 0.01). In patients with normal visual acuity (VA) or visual field MCCS, the TES was 3.3 (SD, 1.8), while that in patients with VA <0.00 was 4.6 (SD, 2.9). CONCLUSIONS: Results of the MCCS test TES were 1.9 times better in patients with PA ≤1 cm compared to patients with PA >1 cm (p < 0.01). In PA patients with normal VA, the TES was 2.35 times worse than that of healthy persons (p < 0.01).
Adenoma/*complications/diagnosis ; Adolescent ; Adult ; Aged ; Color Perception/physiology ; Color Perception Tests/*methods ; Contrast Sensitivity/*physiology ; *Early Diagnosis ; Female ; Humans ; Male ; Middle Aged ; *Optic Chiasm ; Pilot Projects ; Pituitary Neoplasms/*complications/diagnosis ; Time Factors ; Vision Disorders/*diagnosis/etiology/physiopathology ; Visual Fields ; Young Adult

PURPOSE: To investigate patterns of functional magnetic resonance imaging (fMRI) activation during sentence reading before and after wearing color-tinted lenses. METHODS: A total of 15 Meares-Irlen syndrome patients with a mean age of 23.4 years (range, 13 to 42 years) with no history of neurological or psychiatric disorders were scanned using a 3T MR scanner (Siemens, Tim-Trio, Germany). Each patient underwent two sessions of fMRI imaging (before and after MISViS color-tinted lens application). The fMRI paradigm included a block design of 20 seconds of rest (cross), 20 seconds of activation (sentence reading), and ten blocks (a total of 200 echo-planar image volumes) repeated for each session. Data preprocessing and analyses were performed using the SPM8 software package. RESULTS: The reading speed of patients improved more than 20% while wearing the selected lenses. When compared to the before-lens session, the after-lens session identified significant regions of activation in the left middle and superior temporal gyri (paired t-test; maximal z score, 5.38; Montreal Neurological Institute coordinate, -60 / -39 / 0; threshold at p < 0.05; corrected for multiple comparisons using family-wise error). No region of activation at the same threshold was found in the before-lens session as compared to the after-lens session. CONCLUSIONS: In the current study, we confirmed activation in the left middle and superior temporal gyri during sentence reading after wearing color-tinted lenses. These results could explain the effectiveness of color-tinted lenses in patients with Meares-Irlen syndrome.
Adolescent ; Adult ; Brain/*pathology/physiopathology ; Color Perception/*physiology ; Dyslexia/*diagnosis/physiopathology ; *Eyeglasses ; Female ; Humans ; Magnetic Resonance Imaging/*methods ; Male ; Perceptual Disorders/*diagnosis/physiopathology ; Pilot Projects ; Reading ; Syndrome ; Vision Disorders/*diagnosis/physiopathology ; Young Adult

Cerebral achromatopsia, which refers to a loss of color vision, is a rare complication of posterior circulation stroke. We report two patients who presented with achromatopsia and dyschromatopsia (incomplete form of achromatopsia) respectively after acute posterior cerebral artery infarction. Lingual and fusiform gyri within the occipito-temporal area are known to be responsible for color perception.
Color Perception ; Color Vision ; Color Vision Defects ; Humans ; Infarction, Posterior Cerebral Artery ; Posterior Cerebral Artery ; Stroke

PURPOSE: To report a case of compressive optic neuropathy due to a giant unruptured aneurysm of a distal internal carotid artery. CASE SUMMARY: A 68-year-old female presented with a one-week history of visual disturbance in her left eye. The patient had no underlying disease except hypertension. Best corrected visual acuity was 20/20 in the right eye and 8/20 in the left eye. The color perception test showed abnormal findings in the left eye. Slit lamp examination showed no abnormal finding except incipient cataract in both eyes. Additionally, fundus examination showed no abnormal finding. Brain MRI and MRA revealed a 2.4 x 2.2 x 3.0-cm-sized unruptured giant aneurysm on the left internal carotid artery. CONCLUSIONS: A giant aneurysm should be considered as a cause for acute or subacute optic neuropathy in a patient with hypertension.
Aged ; Aneurysm ; Brain ; Carotid Artery, Internal ; Cataract ; Color Perception Tests ; Eye ; Female ; Humans ; Hypertension ; Optic Nerve Diseases ; Visual Acuity

Dynamic color is an important carrier that takes information in some special occupations. However, up to the present, there are no available and objective tests to evaluate dynamic color processing. To investigate the characteristics of dynamic color processing, we adopted two patterns of visual stimulus called "onset-offset" which reflected static color stimuli and "sustained moving" without abrupt mode which reflected dynamic color stimuli to evoke event-related brain potentials (ERPs) in primary color amblyopia patients (abnormal group) and subjects with normal color recognition ability (normal group). ERPs were recorded by Neuroscan system. The results showed that in the normal group, ERPs in response to the dynamic red stimulus showed frontal positive amplitudes with a latency of about 180 ms, a negative peak at about 240 ms and a peak latency of the late positive potential (LPP) in a time window between 290 and 580 ms. In the abnormal group, ERPs in response to the dynamic red stimulus were fully lost and characterized by vanished amplitudes between 0 and 800 ms. No significant difference was noted in ERPs in response to the dynamic green and blue stimulus between the two groups (P>0.05). ERPs of the two groups in response to the static red, green and blue stimulus were not much different, showing a transient negative peak at about 170 ms and a peak latency of LPP in a time window between 350 and 650 ms. Our results first revealed that some subjects who were not identified as color blindness under static color recognition could not completely apperceive a sort of dynamic red stimulus by ERPs, which was called "dynamic red blindness". Furthermore, these results also indicated that low-frequency ERPs induced by "sustained moving" may be a good and new method to test dynamic color perception competence.
Adult ; Color Perception ; physiology ; Color Vision Defects ; diagnosis ; physiopathology ; Event-Related Potentials, P300 ; physiology ; Evoked Potentials, Visual ; physiology ; Female ; Humans ; Male ; Pattern Recognition, Visual ; physiology ; Young Adult

PURPOSE: To report a case of compressive optic neuropathy due to breast cancer metastasis to the periorbital lesion 26 years after the treatment of primary cancer. CASE SUMMARY: A 64-year-old female presented with headache, facial pain and visual disturbance in her left eye for four months. The patient had received chemotherapy and radiotherapy after left breast modified radical mastectomy for invasive ductal carcinoma 26 years previously, and right breast wide resection with axillary dissection nine years earlier. Best corrected visual acuity was 20/20 in the right eye and 8/20 in the left eye. The color perception test showed abnormal findings in the left eye. MRI and PET-CT revealed an enhancing mass in the left periorbital area that was compressing the optic nerve. Partial resection of the tumor and left orbital wall was performed. Adjuvant chemotherapy and radiotherapy was performed after the operation. After two months later, the best corrected visual acuity was 20/20 in the left eye, and the color perception test showed normal findings, which have been maintained for one year. CONCLUSIONS: Prompt management can result in visual recovery in patients with compressive optic neuropathy caused by breast cancer metastasis.
Breast ; Breast Neoplasms ; Carcinoma, Ductal ; Chemotherapy, Adjuvant ; Color Perception Tests ; Eye ; Facial Pain ; Female ; Headache ; Humans ; Mastectomy, Modified Radical ; Middle Aged ; Neoplasm Metastasis ; Optic Nerve ; Optic Nerve Diseases ; Orbit ; Visual Acuity

PURPOSE: To evaluate a customized, portable Farnsworth-Munsell 100 (FM 100) hue viewing booth for compliance with colour vision testing standards and to compare it with room illumination in subjects with normal colour vision (trichromats), subjects with acquired colour vision defects (secondary to diabetes mellitus), and subjects with congenital colour vision defects (dichromats). METHODS: Discrete wavelengths of the tube in the customized booth were measured using a spectrometer using the normal incident method and were compared with the spectral distribution of sunlight. Forty-eight subjects were recruited for the study and were divided into 3 groups: Group 1, Normal Trichromats (30 eyes); Group 2, Congenital Colour Vision Defects (16 eyes); and Group 3, Diabetes Mellitus (20 eyes). The FM 100 hue test performance was compared using two illumination conditions, booth illumination and room illumination. RESULTS: Total error scores of the classical method in Group 2 as mean+/-SD for room and booth illumination was 243.05+/-85.96 and 149.85+/-54.50 respectively (p=0.0001). Group 2 demonstrated lesser correlation (r=0.50, 0.55), lesser reliability (Cronbach's alpha, 0.625, 0.662) and greater variability (Bland & Altman value, 10.5) in total error scores for the classical method and the moment of inertia method between the two illumination conditions when compared to the other two groups. CONCLUSIONS: The customized booth demonstrated illumination meeting CIE standards. The total error scores were overestimated by the classical and moment of inertia methods in all groups for room illumination compared with booth illumination, however overestimation was more significant in the diabetes group.
Adolescent ; Adult ; Color Perception Tests/*instrumentation/*methods/standards ; Color Vision Defects/congenital/*diagnosis/etiology ; Diabetes Complications ; Equipment Design ; Humans ; *Lighting ; Middle Aged ; Young Adult