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Biomedical Physics & Engineering Express Jan 2021Color Vision Deficiency (CVD) is one of the most common types of vision deficiency. People with CVD have difficulty seeing color spectra depending on what types of...
Color Vision Deficiency (CVD) is one of the most common types of vision deficiency. People with CVD have difficulty seeing color spectra depending on what types of retina photoreceptors are impaired. In this paper, the Ishihara test with 38 plates was used to examine the Electroencephalogram (EEG) of ten subjects with CVD plus ten healthy individuals. The recording was performed according to the 10-20 international system. The C-based software was programmed so that subjects could select the number or path in each test plate in the software options while recording EEG. Frequency features in different frequency bands were extracted from the EEG signals of the two groups during the Ishihara test. Statistically significant differences (P < 0.05) between features were assessed by independent samples t-test with False Discovery Rate (FDR) correction. Also, the K-nearest neighbor classifier (KNN) was used to classify the two groups. The results revealed that the most significant difference between the two groups in the Ishihara test images occurred for the electrodes located in the right temporoparietal areas (P4 and T6) of the brain in the Delta, Theta, Beta1, and Beta2 frequency bands. The KNN classifier, using the signals that reported the greatest statistical difference between the two groups, showed that the two groups were distinguishable with 85.2% accuracy. In this way, images from the Ishihara test that would provide the most accurate classification were identified. In conclusion, this research provided new insights into EEG signals of subjects with CVD and healthy subjects based on the Ishihara color vision test.
Topics: Cardiovascular Diseases; Color Perception Tests; Color Vision; Color Vision Defects; Electroencephalography; Humans
PubMed: 33445166
DOI: 10.1088/2057-1976/abdbbc -
Optometry and Vision Science : Official... Oct 2015To compare the static and dynamic accommodative responses measured with the WAM-5500 and the PowerRef-II autorefractors. (Comparative Study)
Comparative Study
PURPOSE
To compare the static and dynamic accommodative responses measured with the WAM-5500 and the PowerRef-II autorefractors.
METHODS
The dynamic and static monocular accommodative responses were measured with the WAM-5500 and the PowerRef-II instruments in 30 pre-presbyopic patients (23.66 [±3.19] years). The spherical equivalent was measured at 0.00, 2.50, and 5.00 diopters (D) of accommodative stimulation for the static measurements. The subjective refraction was also determined. Dynamic accommodation was measured for abrupt changes of stimulus vergence of 2.00 D. Mean and peak velocities of accommodation and disaccommodation were evaluated. For the PowerRef-II, dynamic measurements were calculated for sampling frequencies of 5 and 25 Hz.
RESULTS
For far distance static results, the differences between subjective and WAM-5500 measurements were 0.07 (±0.21) D (p = 0.093) and those between subjective and PowerRef-II measurements were 0.70 (±0.47) D (p = 0.001). The difference in the response measured with both instruments was 0.08 (±0.32) D (p = 0.194) for 2.50 D and -0.32 (±0.48) D (p = 0.001) for 5.00 D of stimulation. For the dynamic mode, the PowerRef-II at 25 Hz measured faster mean and peak velocities of accommodation and disaccommodation than the WAM-5500, with statistically significant (p < 0.05) differences of 0.68 (±1.01), 0.67 (±0.98), 1.26 (±1.19), and 1.42 (±1.53) D/s, respectively. With a sampling frequency of 5 Hz for the PowerRef-II, these differences, which were statistically significant (p < 0.05), were reduced to 0.52 (±0.90), 0.49 (±0.91), 0.83 (±1.07), and 0.83 (±1.31) D/s, respectively.
CONCLUSIONS
There is good agreement between subjective refraction and WAM-5500 measurements. In contrast, the PowerRef-II produced more hyperopic results. There were no differences among instruments at 2.50 D of static stimulation; however, differences were found at 5.00 D. In the dynamic measurements, the PowerRef-II measured faster velocities, partly attributed to the difference in the sampling frequency.
Topics: Accommodation, Ocular; Adult; Female; Humans; Male; Prospective Studies; Refractive Errors; Vision Tests; Visual Acuity; Young Adult
PubMed: 26258276
DOI: 10.1097/OPX.0000000000000685 -
Military Medicine Mar 2017Army vision standards have varied little from Aviation's nominal birth. On the basis of classic Snellen acuity, we simply cannot predict threshold skill levels of any...
BACKGROUND
Army vision standards have varied little from Aviation's nominal birth. On the basis of classic Snellen acuity, we simply cannot predict threshold skill levels of any one individual(s). A growing number of Army Flight Surgeons, clinicians, and vision scientists have argued for the inclusion of contrast acuity metrics within flight physical standards.
METHODS
Previous monitoring of operational contact lens utility in 223 Apache pilots, visual acuity data were gathered under two conditions: high illuminance; low illuminance combined with low contrast. Spectacle, contact lens, and aging influences were evaluated.
RESULTS
The high-contrast Snellen acuities clustered at 20/15 and 20/20. Low-contrast acuities stretched from 20/25 to 20/125. LogMAR analysis highlighted statistical significance between the two acuity sets (p < 0.001) to an unanticipated data spread. The known underlying mechanisms possibly related to this effect are poorly documented; all such variables collectively explain <30% of the known variation in low-illuminance vision.
DISCUSSION
Some pilots possessed the capacity to resolve 20/25 lettering under obfuscating conditions; others were adversely influenced by those same conditions. Snellen acuity involves target recognition; contrast acuity detects threshold differences; both aspects can be important.
CONCLUSION
Prescreening under both vision assessment conditions will help identify and select superior vision performers. The validity and predictability of documenting this effect is targeted within planned future research efforts.
Topics: Adult; Aviation; Biological Variation, Population; Contrast Sensitivity; Humans; Military Personnel; Patient Selection; Vision Tests; Visual Acuity; Workforce
PubMed: 28291480
DOI: 10.7205/MILMED-D-16-00208 -
International Ophthalmology Mar 2022Visual acuity is the most used method to assess visual function in children. Contrast sensitivity complements the information provided for visual acuity, but it is not...
KEY MESSAGES
Visual acuity is the most used method to assess visual function in children. Contrast sensitivity complements the information provided for visual acuity, but it is not commonly used in clinical practice. Digital devices are increasingly used as a method to evaluate visual function, due to multiple advantages. Testing with these devices can improve the evaluation of visual development in children from a few months of age. Visual acuity and contrast sensitivity tests, using eye tracking technology, are able to measure visual function in children across a wide range of ages, objectively, quickly and without need of an experienced examiner.
PURPOSE
To report age-normative values for grating visual acuity and contrast sensitivity in healthy children using a digital device with eye tracking technology and to validate the grating acuity test.
METHODS
In the first project of the study, we examined healthy children aged between 6 months and 7 years with normal ophthalmological assessment. Grating visual acuity (VA) and contrast sensitivity (CS) were assessed using a preferential gaze paradigm with a DIVE (Device for an Integral Visual Examination) assisted with eye tracking technology to provide age norms. For the validation project, we compared LEA grating test (LGT) with DIVE VA in a group of children aged between 6 months and 4 years with normal and abnormal visual development.
RESULTS
Fifty-seven children (2.86 ± 1.55 years) were examined with DIVE VA test and 44 successfully completed DIVE CS test (3.06 ± 1.41 years). Both, VA and CS values increased with age, mainly along the first two years of life. Sixty-nine patients (1.34 ± 0.61 years) were included in the DIVE VA test validation. The mean difference between LGT and DIVE VA was - 1.05 ± 4.54 cpd with 95% limits of agreement (LoA) of - 9.95-7.84 cpd. Agreement between the two tests was higher in children younger than 1 year with a mean difference of - 0.19 ± 4.02 cpd.
CONCLUSIONS
DIVE is an automatic, objective and reliable tool to assess several visual function parameters in children, and it has good agreement with classical VA tests, especially for the first stage of life.
Topics: Child; Contrast Sensitivity; Eye-Tracking Technology; Humans; Infant; Ophthalmology; Vision Tests; Visual Acuity
PubMed: 34622374
DOI: 10.1007/s10792-021-02040-4 -
European Review For Medical and... Jun 2023This study aimed to evaluate the diagnostic accuracy of the intelligent flipper (IFLIP) system in identifying binocular vision anomalies.
OBJECTIVE
This study aimed to evaluate the diagnostic accuracy of the intelligent flipper (IFLIP) system in identifying binocular vision anomalies.
PATIENTS AND METHODS
This study comprised 70 participants aged 18 to 22. Participants underwent comprehensive eye assessments, including measurement of visual acuity, refraction, far and near cover test, stereopsis, and worth four dot test. The manual accommodation amplitude and facility, as well as the IFLIP system test, were also evaluated. The correlation between the indices of the IFLIP and manual accommodation tests was analyzed using multiple regression models, and the diagnostic ability of the IFLIP was characterized using Receiver Operating Curve (ROC) analysis. The significance level was 0.05.
RESULTS
The mean age of the 70 participants was 20.03±0.78 years. The mean manual and IFLIP accommodation facilities were 12.00±3.70 cycle per minute (CPM) and 10.01±2.77 CPM, respectively. No correlation was found between the indices of the IFLIP system and manual accommodative amplitude. However, the regression model showed that the contraction/relaxation ratio of the IFLIP system was positively correlated to the manual accommodation facility, and the average contraction time was negatively correlated with the manual accommodation facility. The ROC analysis proposed a cut-off of 10.15 CPM monocularly for the IFLIP accommodation facility assessment.
CONCLUSIONS
This study indicated that the parameters obtained by the IFLIP system and the manual accommodation facility were comparable, and the IFLIP system had good sensitivity and specificity in the assessment of the accommodation facility, thus may serve as a promising tool for screening and diagnosis of binocular visual function anomalies in clinical and community settings.
Topics: Humans; Young Adult; Adult; Vision, Binocular; Vision Tests; Visual Acuity; Accommodation, Ocular; Sensitivity and Specificity
PubMed: 37401300
DOI: 10.26355/eurrev_202306_32802 -
Translational Vision Science &... Aug 2020To test the validity of the ASTEROID stereotest as a clinical test of depth perception by comparing it to clinical and research standard tests.
PURPOSE
To test the validity of the ASTEROID stereotest as a clinical test of depth perception by comparing it to clinical and research standard tests.
METHODS
Thirty-nine subjects completed four stereotests twice: the ASTEROID test on an autostereo 3D tablet, a research standard on a VPixx PROPixx 3D projector, Randot Circles, and Randot Preschool. Within 14 days, subjects completed each test for a third time.
RESULTS
ASTEROID stereo thresholds correlated well with research standard thresholds ( = 0.87, < 0.001), although ASTEROID underestimated standard threshold (mean difference = 11 arcsec). ASTEROID results correlated less strongly with Randot Circles ( = 0.54, < 0.001) and Randot Preschool ( = 0.64, < 0.001), due to the greater measurement range of ASTEROID (1-1000 arcsec) compared to Randot Circles or Randot Preschool. Stereo threshold variability was low for all three clinical stereotests (Bland-Altman 95% limits of agreement between test and retest: ASTEROID, ±0.37; Randot Circles, ±0.24; Randot Preschool, ±0.23). ASTEROID captured the largest range of stereo in a normal population with test-retest reliability comparable to research standards (immediate = 0.86 for ASTEROID vs. 0.90 for PROPixx; follow-up = 0.68 for ASTEROID vs. 0.88 for PROPixx).
CONCLUSIONS
Compared to clinical and research standards for assessing depth perception, ASTEROID is highly accurate, has good test-retest reliability, and measures a wider range of stereo threshold.
TRANSLATIONAL RELEVANCE
The ASTEROID stereotest is a better clinical tool for determining baseline stereopsis and tracking changes during treatment for amblyopia and strabismus compared to current clinical tests.
Topics: Child, Preschool; Depth Perception; Humans; Reproducibility of Results; Vision Tests; Vision, Binocular; Visual Acuity
PubMed: 32879785
DOI: 10.1167/tvst.9.9.29 -
Translational Vision Science &... Dec 2022Unaddressed near vision impairment (NVI) affects more than 500 million people. Testing near vision is necessary to identify those in need of services. To make such...
PURPOSE
Unaddressed near vision impairment (NVI) affects more than 500 million people. Testing near vision is necessary to identify those in need of services. To make such testing readily accessible, we have developed and validated a new smartphone-based near visual acuity (NVA) test: Peek Near Vision (PeekNV).
METHODS
Two forms of the PeekNV test were developed: (1) quantitative measurement of NVA, and (2) binary screening test for presence or absence of NVI. The validity study was carried out with 483 participants in Sagarmatha Choudhary Eye Hospital, Lahan, Nepal, using a conventional Tumbling "E" Near Point Vision Chart as the reference standard. Bland-Altman limits of agreement (LoA) were used to evaluate test agreement and test-retest repeatability. NVI screening was assessed using Cohen's kappa coefficient, sensitivity, and specificity.
RESULTS
The mean difference between PeekNV and chart NVA results was 0.008 logMAR units (95% confidence interval [CI], -0.005 to 0.021) in right eye data, and the 95% LoA between PeekNV and chart testing were within 0.235 and -0.218 logMAR. As a NVI screening tool, the overall agreement between tests was 92.9% (κ = 0.85). The positive predictive value of PeekNV was 93.2% (95% CI, 89.6% to 96.9%), and the negative predictive value 92.7% (95% CI, 88.9% to 96.4%). PeekNV had a faster NVI screening time (11.6 seconds; 95% CI, 10.5 to 12.6) than the chart (14.9 seconds; 95% CI, 13.5 to 16.2; P < 0.001).
CONCLUSIONS
The PeekNV smartphone-based test produces rapid NVA test results, comparable to those of an accepted NV test.
TRANSLATIONAL RELEVANCE
PeekNV is a validated, reliable option for NV testing for use with smartphones or digital devices.
Topics: Humans; Visual Acuity; Vision Tests
PubMed: 36583912
DOI: 10.1167/tvst.11.12.18 -
Progress in Retinal and Eye Research Jul 2024Patients who suffer from sight-threatening eye diseases share a desire to regain a comfortable reading ability. In light of the modern advances achieved in ophthalmic... (Review)
Review
Patients who suffer from sight-threatening eye diseases share a desire to regain a comfortable reading ability. In light of the modern advances achieved in ophthalmic diagnosis and therapy, and because a significant lack of comparability between reading charts still exists, there is an increasing need for a worldwide standard in the form of a norm for diagnostic reading charts. Already, applied advancements such as digital print, which allow a calibration of the print sizes of reading charts in correctly progressing geometric proportions by using the actual height of a lower case "x" in millimeters (x-height), and psychophysically standardizing reading charts and their test items by applying modern statistical methods have significantly contributed to establishing a norm for reading charts. In 2020, a proposal of the British delegation was accepted by the International Organization for Standardization (ISO) group "Visual Optics and Optical Instruments," and a working group was established. Bearing in mind the efforts of the ISO with regard to an international norm, this review article is intended to (a) give an overview of the historical background and related normative approaches for diagnostic reading tests used in ophthalmology and optometry, (b) explain psychophysical and technical concerns, and (c) discuss the possibilities and limits of concepts that seem relevant to developing a modern standard for reading charts.
Topics: Humans; Reading; Vision Tests; Visual Acuity; Ophthalmology; Reference Standards
PubMed: 38574851
DOI: 10.1016/j.preteyeres.2024.101262 -
Journal of Binocular Vision and Ocular... 2021: Age norms and testability for 3-5 year old children have been reported for the PASS III stereotest using a pointing response. We aimed to expand the normative data to...
: Age norms and testability for 3-5 year old children have been reported for the PASS III stereotest using a pointing response. We aimed to expand the normative data to children as young as 6 months, assess testability, and evaluate validity use of the PASS III as a preferential-looking test for younger children and children with special needs. : 68 control children, 362 children with eye conditions, and 167 children with special needs were tested with the PASS III. Percent testable was calculated for children with and without special needs, normal tolerance limits were determined, and test validity was assessed. : In controls, mean PASS III stereoacuity improved from 371 arcsec at 12 months to 174 arcsec at 24 months, and 87 arcsec at 36 months. Testability in the 12, 24, and 36 months age groups were 81%, 87%, and 97% respectively and 92% for special needs children. Comparison to previously published norms and testing in a known nil stereoacuity cohort supported PASS III test validity. Compared to gold standard stereoacuity tests, accuracy of the PASS was 89%. : Overall, preferential-looking tests using the PASS III provide a sensitive and specific measure of stereoacuity with high testability for young children and children with special needs.
Topics: Child, Preschool; Cohort Studies; Depth Perception; Humans; Physical Examination; Vision Tests; Visual Acuity
PubMed: 33555995
DOI: 10.1080/2576117X.2021.1874776 -
Games For Health Journal Aug 2017Gamification has been incorporated into vision tests and vision therapies in the expectation that it may increase the user experience and engagement with the task. The...
OBJECTIVE
Gamification has been incorporated into vision tests and vision therapies in the expectation that it may increase the user experience and engagement with the task. The current study aimed to understand how gamification affects the user experience, specifically during the undertaking of psychophysical tasks designed to estimate vision thresholds (chromatic and achromatic contrast sensitivity).
METHODS
Three tablet computer-based games were developed with three levels of gaming elements. Game 1 was designed to be a simple clinical test (no gaming elements), game 2 was similar to game 1 but with added gaming elements (i.e., feedback, scores, and sounds), and game 3 was a complete game. Participants (N = 144, age: 9.9-42 years) played three games in random order. The user experience for each game was assessed using a Short Feedback Questionnaire.
RESULTS
The median (interquartile range) fun level for the three games was 2.5 (1.6), 3.9 (1.7), and 2.5 (2.8), respectively. Overall, participants reported greater fun level and higher preparedness to play the game again for game 2 than games 1 and 3 (P < 0.05). There were significant positive correlations observed between fun level and preparedness to play the game again for all the games (p < 0.05). Engagement (assessed as completion rates) did not differ between the games.
CONCLUSION
Gamified version (game 2) was preferred to the other two versions. Over the short term, the careful application of gaming elements to vision tests was found to increase the fun level of users, without affecting engagement with the vision test.
Topics: Adolescent; Adult; Child; Computers, Handheld; Female; Humans; Male; Surveys and Questionnaires; User-Computer Interface; Video Games; Vision Tests
PubMed: 28691854
DOI: 10.1089/g4h.2016.0100