-
Eye (London, England) Jun 2023Keratoconus is associated with thinning and anterior protrusion of the cornea resulting in the symptoms of blurry and distorted vision. The commonly used clinical vision...
BACKGROUND
Keratoconus is associated with thinning and anterior protrusion of the cornea resulting in the symptoms of blurry and distorted vision. The commonly used clinical vision tests such as visual acuity and contrast sensitivity may not reflect the symptoms experienced in keratoconus and there are no quantitative tools to measure visual distortion. In this study, we used a quantitative test based on vernier alignment and field matching techniques to quantify visual distortion in keratoconus and assess its relation to corneal structural changes.
METHODS
A total of 50 participants (25 keratoconus and 25 visually normal) completed the experiment where they aligned supra-threshold white target circles in opposite field in reference to guidelines and circles to complete a square structure monocularly. The task was repeated five times and the global distortion index (GDI) and global uncertainty index (GUI) were calculated as the mean and standard deviation respectively of local perceived misalignment of target circles over five trials.
RESULTS
Both GDI and GUI were higher in participants with keratoconus compared to controls (p < 0.01). Both parameters correlated with the best corrected visual acuity, maximum corneal curvature (K), topographical keratoconus classification (TKC) and central corneal thickness (CCT).
CONCLUSION
Our findings show that the quantitative measure of distortion could be a useful tool for behavioural assessment of progressive keratoconus.
Topics: Humans; Keratoconus; Corneal Topography; Cornea; Visual Acuity; Vision, Ocular
PubMed: 36104521
DOI: 10.1038/s41433-022-02240-x -
Eye (London, England) Dec 2023Home visual acuity tests could ease pressure on ophthalmic services by facilitating remote review of patients. Home tests may have further utility in giving service...
BACKGROUND
Home visual acuity tests could ease pressure on ophthalmic services by facilitating remote review of patients. Home tests may have further utility in giving service users frequent updates of vision outcomes during therapy, identifying vision problems in an asymptomatic population, and engaging stakeholders in therapy.
METHODS
Children attending outpatient clinics had visual acuity measured 3 times at the same appointment: Once by a registered orthoptist per clinical protocols, once by an orthoptist using a tablet-based visual acuity test (iSight Test Pro, Kay Pictures), and once by an unsupervised parent/carer using the tablet-based test.
RESULTS
In total, 42 children were recruited to the study. The mean age was 5.6 years (range 3.3 to 9.3 years). Median and interquartile ranges (IQR) for clinical standard, orthoptic-led and parent/carer-led iSight Test Pro visual acuity measurements were 0.155 (0.18 IQR), 0.180 (0.26 IQR), and 0.300 (0.33 IQR) logMAR respectively. The iSight Test Pro in the hands of parents/carers was significantly different from the standard of care measurements (P = 0.008). In the hands of orthoptists. There was no significant difference between orthoptists using the iSight Test Pro and standard of care (P = 0.289), nor between orthoptist iSight Test Pro and parents/carer iSight Test Pro measurements (P = 0.108).
CONCLUSION
This technique of unsupervised visual acuity measures for children is not comparable to clinical measures and is unlikely to be valuable to clinical decision making. Future work should focus on improving the accuracy of the test through better training, equipment/software or supervision/support.
Topics: Humans; Child; Child, Preschool; Prospective Studies; Vision Tests; Visual Acuity; Research Design
PubMed: 37328509
DOI: 10.1038/s41433-023-02597-7 -
Investigative Ophthalmology & Visual... Jan 2022To assess whether monocular contrast sensitivity and stereoacuity impairments remain when visual acuity is fully recovered in children with refractive amblyopia.
PURPOSE
To assess whether monocular contrast sensitivity and stereoacuity impairments remain when visual acuity is fully recovered in children with refractive amblyopia.
METHODS
A retrospective review of 487 patients diagnosed with refractive amblyopia whose visual acuity improved to 0.08 logMAR or better in both eyes following optical treatment was conducted. Measurements of monocular contrast sensitivity and stereoacuity had been made when visual acuity normalized. All patients had been treated with refractive correction for approximately 2 years following diagnosis. No other treatments were provided. Monocular contrast sensitivity was measured using the CSV-1000E chart for children 6 years of age or younger and a psychophysical technique called the quick contrast sensitivity function in older children. Stereoacuity was measured using the Random Dot Test that includes monocular cues and the Randot Stereoacuity Test that does not have monocular cues.
RESULTS
Statistically significant interocular differences in contrast sensitivity were observed. These differences tended to occur at higher spatial frequencies (12 and 18 cycles per degree). Stereoacuity within the age-specific normal range was achieved by 47.4% of patients for the Random Dot Test and only 23.1% of patients for the Randot Stereoacuity Test.
CONCLUSIONS
Full recovery of visual acuity following treatment for refractive amblyopia does not equalize interocular contrast sensitivity or restore normal stereopsis. Alternative therapeutic approaches that target contrast sensitivity and/or binocular vision are required.
Topics: Amblyopia; Child; Child, Preschool; Contrast Sensitivity; Depth Perception; Eyeglasses; Female; Humans; Hyperopia; Male; Myopia; Retrospective Studies; Sensory Deprivation; Vision Tests; Vision, Binocular; Visual Acuity
PubMed: 34989762
DOI: 10.1167/iovs.63.1.6 -
Journal of Safety Research Feb 2020The present study proposes to validate the Driver Ecological Glare Test (DEGT), a test developed to measure the benefit of a headlight glare Advanced Driver Assistance...
INTRODUCTION
The present study proposes to validate the Driver Ecological Glare Test (DEGT), a test developed to measure the benefit of a headlight glare Advanced Driver Assistance System (ADAS), by comparing it to a laboratory glare test.
METHOD
Twenty-four participants, aged from 55 to 70 years, were recruited to complete a visual examination, including monocular halo size measurement for both eyes using Vision Monitor device (MonCv3; Metrovision). An on-field evaluation took place at night at the UTAC CERAM test track to obtain disability glare measures using the DEGT.
RESULTS
A significant correlation was found between the two glare tests and Bland-Altman analysis reveals a good agreement with a bias of 73.7 arcmin between the halo size measurements obtained from the DEGT and Vision Monitor. The results of the present study demonstrate that the DEGT is a valid method to test halo size and is adapted to evaluate the benefits of an antiglare device for drivers in an ecological situation.
Topics: Aged; Automobile Driving; Female; France; Glare; Humans; Male; Middle Aged; Safety; Vision Tests; Visual Acuity
PubMed: 32199556
DOI: 10.1016/j.jsr.2019.12.007 -
Scientific Reports Apr 2024Primary congenital glaucoma is a rare disease that occurs in early birth and can lead to low vision. Evaluating affected children is challenging and there is a lack of...
Primary congenital glaucoma is a rare disease that occurs in early birth and can lead to low vision. Evaluating affected children is challenging and there is a lack of studies regarding color vision in pediatric glaucoma patients. This cross-sectional study included 21 eyes of 13 children with primary congenital glaucoma who were assessed using the Farnsworth D-15 test to evaluate color vision discrimination and by spectral domain optical coherence tomography to measure retinal fiber layer thickness. Age, visual acuity, cup-to-disc ratio and spherical equivalent data were also collected. Global and sectional circumpapillary and macular retinal fiber layer thicknesses were measured and compared based on color vision test performance. Four eyes (19%) failed the color vision test with diffuse dyschromatopsia patterns. Only age showed statistical significance in color vision test performance. Global and sectional circumpapillary and macular retinal fiber layer thicknesses were similar between the color test outcomes dyschromatopsia and normal. While the color vision test could play a role in assessing children with primary congenital glaucoma, further studies are needed to correlate it with damage to retinal fiber layer thickness.
Topics: Humans; Female; Male; Child; Cross-Sectional Studies; Tomography, Optical Coherence; Glaucoma; Child, Preschool; Color Vision; Visual Acuity; Adolescent; Color Vision Defects; Color Perception; Retina; Color Perception Tests
PubMed: 38664551
DOI: 10.1038/s41598-024-60320-2 -
Clinical & Experimental Optometry Apr 2022Measuring reading ability is a crucial part of assessing patients who complain of reduced vision. Foreign language versions of such charts need to be developed and...
CLINICAL RELEVANCE
Measuring reading ability is a crucial part of assessing patients who complain of reduced vision. Foreign language versions of such charts need to be developed and validated.
BACKGROUND
It is difficult to measure or predict Korean reading ability due to a lack of a representative reading charts in Korean, and previous charts have limited capacity to detect deficits in reading ability among Korean patients with eye diseases.
METHODS
Two printed versions of the reading chart were created. Thirty-four patients with no change in vision in the last three months and no expected change in vision in the next four weeks were included in this study. The results were validated by testing 13 normal-sighted adults (group 1), 14 patients with various macular diseases whose visual acuity was equal or better than 0.5 logarithm of the minimum angle of resolution (logMAR) (group 2), and seven patients with various macular diseases whose visual acuities were between 1.3 logMAR and 0.5 logMAR (group 3). Inter-chart and intra-subject repeatabilities were assessed for maximum reading speed (MRS) and critical print size (CPS).
RESULTS
A total of 38 sentences were tested on 34 adults in three groups. Groups 1 and 2 did not differ significantly in terms of MRS and CPS. The MRS was lower in group 3, for each chart and between visits. The CPS was larger in group 3, for each chart and between visits, with the exception of chart 2 during visit one. With regard to test-retest reliability, the intraclass correlation co-efficients (ICCs) for chart 1 and chart 2 were more than 0.900. With regard to inter-chart reliability, the ICCs were more than 0.892, respectively.
CONCLUSION
The reading chart developed in this study was reliable in producing consistent results among a normal Korean population and patients with various macular diseases.
Topics: Adult; Humans; Language; Reading; Reproducibility of Results; Republic of Korea; Vision Tests
PubMed: 33941049
DOI: 10.1080/08164622.2021.1908821 -
Radiography (London, England : 1995) May 2020Deterioration of visual acuity (VA) and visual impairment has been linked to age-related subtle changes, gender, and a correlation to socioeconomic status. This study...
INTRODUCTION
Deterioration of visual acuity (VA) and visual impairment has been linked to age-related subtle changes, gender, and a correlation to socioeconomic status. This study aimed to assess first-year diagnostic radiography students' visual functional abilities by applying the International Classification of Impairments, Disabilities and Handicaps (ICIDH) recommendations of functional VA screening and health-related quality of life questionnaire (HRQOL).
METHODS
The design followed the World Health Organisation (WHO) electronic VA testing of monocular sight using LogMAR charts and binocular vision using Snellen charts, and an HRQOL questionnaire assessing for reduced ability of visual-based tasks in activities of daily living (ADL). The data was evaluated in correlation to the participant's visual correction, age, gender, and socioeconomic background.
RESULTS
Seventy students were recruited, all meeting the WHO standard level for visual ability, with 100% (n = 70/70) met or achieved above normal binocular vision, correlating to expected normal population results from published studies for age. The monocular vision demonstrated 74% (n = 52/70) for the right eye, and 80% (n = 56/70) for the left eye for normal vision levels. The results did not differ significantly between each eye (p = 0.21), gender variations between the left eye (p = 0.27) and the right eye (p = 0.10) results were affected by sample ratio of females (80%; n = 56/70) to males (20%; n = 14/70), the visual correction did not impair binocular VA. The HRQOL assessment indicated no significant functional VA issues in the study sample. The study demonstrated no association between the participant's socioeconomic background that may influence their VA ability.
CONCLUSION
The results provided normative binocular and monocular data on visual function in a sample of student radiographers and indicated that their thresholds align to normal (or near-normal) VA standards.
IMPLICATIONS FOR PRACTICE
The visual health data was reviewed for subgroup comparison and trend analysis, and did not identify risk factors within this sample group that their VA and visual functioning would impact upon radiography clinical placement tasks and activities. The sample is not generalisable to the wider population; further studies are recommended.
Topics: Activities of Daily Living; Adult; Female; Humans; Male; Quality of Life; Students, Health Occupations; Technology, Radiologic; Vision Tests; Vision, Binocular; Vision, Monocular; Visual Acuity
PubMed: 32052772
DOI: 10.1016/j.radi.2019.10.012 -
Military Medicine Jan 2023Color vision deficiency (CVD) is a disqualifying condition for military special duty occupations. Color vision testing and standards vary slightly among the U.S....
INTRODUCTION
Color vision deficiency (CVD) is a disqualifying condition for military special duty occupations. Color vision testing and standards vary slightly among the U.S. military branches. Paper-based pseudoisochromatic plates (PIPs) remain a screening tool. Computer-based color vision tests (CVTs), i.e., the Cone Contrast Test (CCT), the Colour Assessment and Diagnosis (CAD) test, and the Waggoner Computerized Color Vision Test (WCCVT), are now replacing the Farnsworth Lantern Test (FALANT) and its variants to serve as a primary or secondary test in the U.S. Armed Forces. To maintain consistency in recruitment, performance, and safety, the study objectives were to examine military color vision testing, passing criteria, and color discrimination performance.
METHODS
Study participants were 191 (17% female) students, faculty, and staff of the U.S. Air Force Academy and the Naval Aerospace Medical Institute. All subjects performed six CVTs, and 141 participants completed two additional military relevant color discrimination tasks. Friedman non-parametric test and Wilcoxon signed-rank post hoc test with Bonferroni adjusted P values were used to compare CVTs and standards. Analysis of variance and Bonferroni adjusted post hoc test were used to describe effects on color discrimination performance.
RESULTS
The Heidelberg Multicolor-Moreland and Rayleigh (HMC-MR) anomaloscope diagnosed 58 CVD (30.4%). There were no statistically significant differences in identifying red-green CVD by the HMC-MR, CCT, CAD, WCCVT, and PIP tests (P = .18), or classifying deutan, protan, and normal color vision (CVN) by the HMC-MR and the CVT (P = .25). Classification of tritan CVD was significantly different depending on which CVT was used (P < .001). Second, overall passing rates were 79.1% on the CAD (≤6 standard normal unit (SNU)), 78.5% on the combined PIP/FALANT, 78.0% on the CCT (≥55%), and 75.4% on the WCCVT (mild) military standards. The CVTs and the PIP/FALANT standards were not significantly different in number of personnel selected, but CAD and CCT passed significantly more individuals than WCCVT (P = .011 and P = .004, respectively). The previous U.S. Air Force standard (CCT score ≥75%) passed significantly fewer individuals relative the U.S. Navy pre-2017 PIP/FALANT or the current CVT standards (P ≤ .001). Furthermore, for those who failed the PIP (<12/14), the FALANT (9/9 or ≥16/18) agreed with the CVTs on passing the same CVN (n = 5); however, it also passed moderate-to-severe CVD who did not pass WCCVT (n = 6), CCT (n = 3), and CAD (n = 1). Lastly, moderate/severe CVD were significantly slower and less accurate than the "mild" CVD or CVN in the two color discrimination tasks (P < .001). In comparison to CVN in the in-cockpit display color discrimination task, mild CVD (CCT ≥55% and <75%) were significantly slower by 1,424 ± 290 milliseconds in reaction time (P < .001) while maintaining accuracy.
CONCLUSIONS
CVTs are superior to paper-based PIP in diagnosing, classifying, and grading CVD. Relative to the PIP/FALANT standard in personnel selection, the current U.S. military CVT passing criteria offer comparable passing rates but are more accurate in selecting mild CVD. Nevertheless, military commanders should also consider specific operational requirements in selecting mild CVD for duty as reduced job performance may occur in a complex color critical environment.
Topics: Humans; Female; Male; Color Vision; Color Perception Tests; Military Personnel; Color Vision Defects; Cardiovascular Diseases
PubMed: 35352814
DOI: 10.1093/milmed/usac080 -
BMC Ophthalmology Mar 2022To assess dynamic visual acuity (DVA) under different defocus statuses and explore the assessment of dynamic vision accommodation.
BACKGROUND
To assess dynamic visual acuity (DVA) under different defocus statuses and explore the assessment of dynamic vision accommodation.
METHODS
Twenty subjects (6 males and 14 females) aged 18 to 35 were recruited. Nonmydriatic subjective refraction (sphere and cylinder) and accommodative tests including negative relative accommodation (NRA), positive relative accommodation (PRA), binocular cross cylinder (BCC) and accommodative facility using a flipper were performed. Binocular static visual acuity (SVA) and DVA at 40 degrees per second (dps) were measured under different defocus statuses (+1.5D to -4D in -0.5D steps) based on the refractive error fully corrected. Static and dynamic defocus curves were plotted. The area under the curve (AUC) and corrected dynamic vision accommodation (CDVAc) were calculated.
RESULTS
The study showed that the dynamic defocus curve fitted the cubic curve properly (p<0.001). DVA was significantly worse than SVA at all defocused statuses (p<0.001), and the difference was more significant at greater defocus diopters. Single factor analysis indicated that CDVAc was significantly correlated with NRA-PRA (p=0.012) and AUC (p<0.001). Significant associations were observed between AUC and PRA (p=0.013) as well as NRA-PRA (p=0.021). Meanwhile, DVA was positively correlated with PRA at 0D, -1.0D, -1.5D, -2.5D and -3.0D (p<0.05) and with NRA-PRA at 0D, -1.0D, -1.5D, -2.0D and -2.5D (p<0.05). Multiple factor regression analysis indicated that CDVAc (0D ~ -3.5D) and SVA (+1.5D ~ +1.0D & -2.5D ~ -4.0D) were significant influential factors for defocused DVA (p<0.05).
CONCLUSIONS
Our study demonstrated that DVA had a defocus curve similar to that of SVA. CDVAc was feasible for the assessment of dynamic vision accommodative function. The dynamic defocus curve test could efficiently be applied in the evaluation of dynamic visual performance under different defocus statuses.
Topics: Accommodation, Ocular; Adolescent; Adult; Female; Humans; Male; Refractive Errors; Vision Tests; Vision, Binocular; Visual Acuity; Young Adult
PubMed: 35248018
DOI: 10.1186/s12886-022-02335-9 -
Vision Research May 2020The current study explored the effects of contrast adaptation on the accommodation response (AR), using low- and high-pass filtered video clips as stimuli. Ten young...
The current study explored the effects of contrast adaptation on the accommodation response (AR), using low- and high-pass filtered video clips as stimuli. Ten young myopic (mean ± standard deviation: -2.91 ± 1.36D) and 10 near emmetropic subjects (-0.19 ± 0.14D) participated in the study. The AR was monitored under monocular viewing conditions using an eccentric infrared photorefractor. A 2-stage procedure was used: (1) the minimum spatial frequency content necessary to produce a proper individual AR; and (2) the AR was compared before and after adaptation to low-pass (s = -0.5), control (s = 0) and high-pass (s = +0.5) filtered videos. We found that (1) the average threshold Sinc-blur of both myopes and emmetropes necessary to evoke accommodation was (mean ± standard deviation) λ = 7.40 ± 4.05 cpd. Myopes required a higher Sinc blur (average, 10.00 ± 4.05 cpd) compared to emmetropes (average, 4.80 ± 1.60 cpd). (2) Adaptation to low-pass filtered videos increased the AR by 0.41 ± 0.33D in the myopic group and reduced it in the emmetropic group by 0.31 ± 0.25D. Adaptation to high pass-filtered videos induced similar changes in both refractive groups (an increase of 0.41 ± 0.40D and 0.46 ± 0.29D for myopes and emmetropes, respectively). Our measurements show that the human AR can be modified by spatial frequency selective contrast adaptation although these were short-term effects. The perhaps most striking finding was that adaptation to low pass filtered videos had opposite effects on the AR in emmetropes and myopes. It remains to be studied whether these differences were a consequence of myopia or a contributing factor in myopia development.
Topics: Accommodation, Ocular; Adaptation, Physiological; Emmetropia; Humans; Myopia; Vision Tests
PubMed: 32217367
DOI: 10.1016/j.visres.2020.03.003