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Journal of Optometry 2022Why myopia develops, why it is reaching epidemic proportions and what is its cause are questions that puzzle many people. There is an answer to these questions and it is... (Review)
Review
Why myopia develops, why it is reaching epidemic proportions and what is its cause are questions that puzzle many people. There is an answer to these questions and it is a simple one. This paper makes the connection between ametropic and in particular myopic development and theory to come with a summary of what we know about myopia and its governing equation. Key experiments, involving myopia and the effect of lenses in humans and animals have been done with unmistakable results. The observed effect of lenses implies a feedback mechanism. Feedback theory explains those results with mathematical precision. Disruption of emmetropization, is the mechanism behind ametropia and particularly myopia. Feedback theory for emmetropization was derived by observation of the input and output of the emmetropization feedback system in many patients. We show that it has the same equation as it is derived here independently from simple homeostasis principles. Classical observations and recent clinical studies have shown the association of many variables with myopia. They include near work, atropine, lenses, blur and outdoors versus indoors activities. We propose that human refractive development is controlled by homeostasis and based on that alone we derive the equation for the calculation of refraction for any patient and the effect of lenses. We provide software to calculate the refraction of any individual at any time. The editor of this journal makes the following statement: "This manuscript is intended for scientific discussion rather than clinical application. The present work does not intend to promote clinical under correction or no correction of myopia. Instead, clinicians should follow current clinical myopia management guidelines."
Topics: Animals; Humans; Myopia; Refraction, Ocular; Refractive Errors; Vision Tests
PubMed: 34600857
DOI: 10.1016/j.optom.2021.08.001 -
Seminars in Pediatric Neurology Oct 2019The complete assessment of vision-related abilities should consider visual function (the performance of components of the visual system) and functional vision (visual... (Review)
Review
The complete assessment of vision-related abilities should consider visual function (the performance of components of the visual system) and functional vision (visual task-related ability). Assessment methods are highly dependent upon individual characteristics (eg, the presence and type of visual impairment). Typical visual function tests assess factors such as visual acuity, contrast sensitivity, color, depth, and motion perception. These properties each represent an aspect of visual function and may impact an individual's level of functional vision. The goal of any functional vision assessment should be to measure the visual task-related ability under real-world scenarios. Recent technological advancements such as virtual reality can provide new opportunities to improve traditional vision assessments by providing novel objective and ecologically valid measurements of performance, and allowing for the investigation of their neural basis. In this review, visual function and functional vision evaluation approaches are discussed in the context of traditional and novel acquisition methods.
Topics: Behavior; Brain Mapping; Contrast Sensitivity; Humans; Vision Disorders; Vision Tests; Visual Acuity
PubMed: 31548022
DOI: 10.1016/j.spen.2019.05.006 -
Indian Journal of Ophthalmology Oct 2023In Humphrey visual field analyzer, the false-positive (FP) responses imply that the patient has pressed the response button despite no stimulus being seen at the time of...
BACKGROUND
In Humphrey visual field analyzer, the false-positive (FP) responses imply that the patient has pressed the response button despite no stimulus being seen at the time of response and FP rates >15% are flagged. The classical "Trigger happy" visual field has increased fixation loss, very high threshold retinal sensitivity with the values in supernormal range, "white scotoma" on grayscale map, high positive mean deviation (MD), glaucoma hemifield test (GHT) gives classification of "abnormally high sensitivity, 'Excessive high false positive' message is displayed," and pattern deviation probability plot has more defects than total deviation probability plot known as "reverse cataract pattern." However, these classical findings are not seen in all the cases of FP as the same thumb rule cannot be applied to all the visual fields with high FP.
PURPOSE
This video emphasizes the significance of careful examination of all the parameters in a visual field printout of high FP to interpret the test results and the caution needed when an FP response is seen in a patient with advanced glaucoma.
SYNOPSIS
The video presents some interesting visual fields in normal and glaucoma patients and the effect of high FP responses on MD, the different classification messages displayed for GHT, patterns of total deviation probability plot and pattern deviation probability plot, and how to identify the hidden FP.
HIGHLIGHTS
This video highlights the importance of careful examination of all the parameters in a visual field printout to interpret the test results. One should be especially cautious when an FP response is noted in a patient with advanced glaucoma, as the retinal sensitivity values may not be in supernormal range but are significantly affected by the increased FP. Clinician should be able to identify this and repeat the test as high FP reponses can lead to underestimation of visual field loss.
VIDEO LINK
https://youtu.be/T2SGZf16UzA.
Topics: Humans; Visual Field Tests; Visual Fields; Glaucoma; Scotoma; Vision Disorders
PubMed: 37787253
DOI: 10.4103/IJO.IJO_601_23 -
Translational Vision Science &... Dec 2020To investigate contrast sensitivity measures in glaucoma eyes with moderate to severe glaucoma.
PURPOSE
To investigate contrast sensitivity measures in glaucoma eyes with moderate to severe glaucoma.
METHODS
The study included 50 eyes of 47 pseudophakic patients with moderate or severe glaucoma who were seen at a tertiary center from 2017 to 2020. Assessment of contrast sensitivity using the Spaeth/Richman contrast sensitivity (SPARCS) test and the Pelli-Robson (PR) chart was compared in eyes with mean deviation (MD) < -12 decibels (dB) and > -20 dB (group 1), MD < -20 dB and > -30 dB (group 2), or MD < -30 dB (group 3). Multivariate regression analysis was used to analyze the association of visual field MD with SPARCS/PR scores and various clinical variables, including age, diagnosis, and logMar visual acuity.
RESULTS
SPARCS total scores and quadrant-wise scores were significantly different in all of the quadrants, whereas central scores and PR contrast sensitivity were similar across groups. The total SPARCS scores predicted the change in MD (β = 0.5, < 0.001, = 61.8%) with minimal association of other quadrantic or PR scores. Total SPARCS scores of <45 and <38 predicted severe glaucoma with MD crossing -20 dB (sensitivity, 70.5%; specificity, 80.9%) and -30 dB (sensitivity, 79.3%; specificity, 77.7%), respectively. The logMar visual acuity did not correlate with any contrast sensitivity measure or clinical variables in this study.
CONCLUSIONS
The total SPARCS score may be used in staging glaucoma severity and to assess visual function in eyes with severe glaucoma.
TRANSLATIONAL RELEVANCE
The SPARCS test is a useful tool for assessing visual function in advanced glaucoma beyond MD worse than -20 dB or -30 dB.
Topics: Contrast Sensitivity; Glaucoma; Humans; Prospective Studies; Vision Tests; Visual Fields
PubMed: 33384893
DOI: 10.1167/tvst.9.13.39 -
Translational Vision Science &... Dec 2020To evaluate the test-retest reliability and validity of the MNREAD test for use in children with vision impairment (VI) and to compare their performance on the test to...
PURPOSE
To evaluate the test-retest reliability and validity of the MNREAD test for use in children with vision impairment (VI) and to compare their performance on the test to that of normally sighted children.
METHODS
Children with VI ( = 62) and without VI ( = 40) were administered the MNREAD test and the Basic Reading Inventory (BRI) on two study visits, 1 to 3 weeks apart. The maximum reading rate, critical print size, and reading acuity were determined for the MNREAD test, and test-retest reliability was evaluated. The reading rate for the MNREAD test was compared to the BRI results.
RESULTS
Strong correlations between visits were found for all MNREAD parameters (0.68-0.99). Older, but not younger, children with VI read significantly more slowly on both the MNREAD and the BRI than children with normal vision ( < 0.05). Reading rates between the two tests were strongly correlated ( = 0.88). For the MNREAD test, the reading rate increased 4.4 words per minute (wpm) per year for VI and 10.6 wpm/y for those with normal vision. For the BRI, the reading rate increased by 5.9 wpm/y for VI and 9.7 wpm/y for those with normal vision. Poorer visual acuity was associated with slower reading rates on the MNREAD test but not on the BRI, as the MNREAD relies largely on visual factors but the BRI also relies on linguistic and grammar skills.
CONCLUSIONS
The MNREAD test are reliable and valid for use in children with vision impairment.
TRANSLATIONAL RELEVANCE
The MNREAD test can be utilized by clinicians, as they are a quick, easy-to-administer method for evaluating reading vision in children with VI.
Topics: Child; Humans; Reading; Reproducibility of Results; Vision Tests; Vision, Low; Visual Acuity
PubMed: 33384883
DOI: 10.1167/tvst.9.13.25 -
Optometry and Vision Science : Official... Sep 2021The Ohio Contrast Cards are a repeatable test of contrast sensitivity, and they reveal higher contrast sensitivity for low-vision patients than is shown by the...
SIGNIFICANCE
The Ohio Contrast Cards are a repeatable test of contrast sensitivity, and they reveal higher contrast sensitivity for low-vision patients than is shown by the Pelli-Robson chart.
PURPOSE
This study aimed to compare the contrast sensitivity results and test/retest ±limits of agreement for the Ohio Contrast Cards and the Pelli-Robson letter contrast sensitivity chart on two challenging groups of participants, and to compare the Ohio Contrast Card results with grating acuity and the Pelli-Robson results with letter acuity.
METHODS
The Ohio Contrast Card and Pelli-Robson tests were each performed twice by two different examiners within one visit on 40 elder patients in Primary Vision Care (>65 years old) and 23 to 27 low-vision school-aged students. Grating acuity was measured using the Teller Acuity Cards (all participants), and letter acuity was measured using ClearChart (elders) or the Bailey-Lovie chart (students).
RESULTS
The ±95% limits of agreement were similar for the Ohio Contrast Cards and the Pelli-Robson chart. The elders' limits of agreement were ±0.27 (Ohio Contrast Cards) and ±0.28 (Pelli-Robson); the students' limits of agreement were ±0.42 (Ohio Contrast Cards) and ±0.51 (Pelli-Robson). However, Ohio Contrast Card results were 0.41 log10 Michelson units more sensitive than the Pelli-Robson chart (over one line on the Pelli-Robson chart) for the elders and 0.90 log10 Michelson units (three lines on the Pelli-Robson chart) more sensitive for the elders (0.11 and 0.6 log10 Weber units, respectively). The Pelli-Robson results were correlated with letter acuities and Ohio Contrast Card results for both groups, and the Ohio Contrast Card results were correlated with Teller Acuity Card acuities for the elders.
CONCLUSIONS
The Ohio Contrast Cards and Pelli-Robson chart are similarly repeatable. Both contrast sensitivity tests can provide additional clinical information that is not available through visual acuity testing, and Ohio Contrast Card may provide additional information not available from the Pelli-Robson chart.
Topics: Aged; Child; Contrast Sensitivity; Humans; Ohio; Vision Tests; Vision, Low; Visual Acuity
PubMed: 34570031
DOI: 10.1097/OPX.0000000000001771 -
PloS One 2023For a good vision screening battery to quickly and accurately reflect the status of the human visual system it should be relevant, reliable, and streamlined. Because the...
For a good vision screening battery to quickly and accurately reflect the status of the human visual system it should be relevant, reliable, and streamlined. Because the early visual system has limited functional architecture, many simple measurements of the visual system may in fact be measuring the shared computations and parallel processes of other visual functions, making much of the measurement process redundant. This can make a screening battery repetitious and therefore inefficient. The purpose of this research is to investigate these redundancies in a large occupational screening dataset using factor analysis. 192 subjects participated in the Operational Based Vision Assessment (OBVA) Laboratory Automated Vision Testing (AVT) procedure. The AVT includes digital tests for visual acuity, luminance and cone contrast sensitivity, motion coherence, stereopsis, and binocular motor function. Psychometric thresholds and fusional ranges were collected from each subject and a factor analysis was utilized to investigate independent latent variables in the dataset. A promax rotation revealed 5 factors that explained 74% of the total variance: (1) medium and high spatial frequency vision, (2) stereoacuity and horizontal fusional range, (3) cone contrast sensitivity, (4) motion perception, and (5) low spatial frequency vision. Practically, these results suggest that the screening battery can be reduced to 5 independent measurements that capture much of the variance in the dataset. Furthermore, the factors predicted operational and vocational aptitude better than any single variable. More interestingly, these relationships also reiterate known computational processes within the human visual system, such as the parallel processing of low and high spatial frequency content.
Topics: Humans; Vision Screening; Aptitude; Depth Perception; Visual Acuity; Vision, Ocular; Vision Tests; Vision, Binocular
PubMed: 37256907
DOI: 10.1371/journal.pone.0286513 -
Annali Di Igiene : Medicina Preventiva... 2021Data were collected through a nationwide survey conducted in 2018. All maternity wards active in Italy in 2017 were included.
MATERIALS AND METHODS
Data were collected through a nationwide survey conducted in 2018. All maternity wards active in Italy in 2017 were included.
BACKGROUND
The aims of this paper were to present data on the implementation and coverage of simultane-ous Universal Neonatal Hearing and Vision Screening programmes and to evaluate the organization and management of these healthcare procedures in Italy.
CONCLUSIONS
Our results show that implementation of simultaneous hearing and vision screening increased the coverage of both screening tests and is a new multi-disciplinary approach to sensorineural disability. The use of both ABR and TEOAE tests in the hearing screening decreases the number of newborns sent for audiological evaluation, with a notable reduction of costs. The consideration that ocular problems are two to three times more common in deaf and hearing impaired children than their in hearing peers, confirms the importance of establishing guidelines for simultaneous hearing and vision screening, that favors the formation of a multi-disciplinary team (pediatrician, audio-logist, ophthalmologist).
RESULTS
HEARING SCREENING. Overall 427,365 newborns out of 448,386 (95.3%) received the hearing screening test (first level) in 391 out of the 409 maternity hospitals (95.5%), with a national mean referral rate of 3.63% (SD ± 4.58). A statistically significant increase (p<0.034) of newborns sent to audiological examination was found in maternity hospitals with Neonatal Intensive Care Unit (NICU) with "TEOAE only" protocol (9.32% SD ± 7.57), compared to those with "TEOAE/AABR" (3.0% SD ± 3.29). VISION SCREENING. Overall 335,262 newborns out of 448,386 (74.7%) received vision screening (Red Reflex test) for vision impairment in 302 out of 409 maternity hospitals (73.8%), before nursery discharge. The mean referral rate, recorded in only 22 maternity hospitals out of 302 (7.2%), was 0.48% with a rate of lost to follow up of 0.75 %.
Topics: Child; Female; Hearing; Hearing Tests; Humans; Infant, Newborn; Italy; Neonatal Screening; Pregnancy; Vision Screening
PubMed: 33300945
DOI: 10.7416/ai.2020.2401 -
Journal of Optometry 2021To evaluate whether tobacco affects color vision in young moderate smokers.
PURPOSE
To evaluate whether tobacco affects color vision in young moderate smokers.
METHODS
Chromatic mechanisms of 13 moderate smokers (10-20 cigarettes/day and at least 5 years smoking) and 17 non-smokers in the 18-35 age range were assessed with the Farnsworth-Munsell 100-hue (FM100h) test and short wavelength automated perimetry (SWAP).
RESULTS
FM100h Total Error Scores (TES) were higher for smokers, and although differences were not significant (p = 0.14), a linear model with principal component analysis was able to explain 95% of the variance in TES and red-green partial error scores, though not in blue-yellow partial error scores (p = 0.07), using the number of years as smokers and the number of cigarettes/day as predictors. SWAP sensitivity values were globally worse (p = 0.002) for smokers (25.7 + 6.2 dB) than for non-smokers (26.7 + 6.2 dB). In the upper visual hemifield sensitivity, total deviation and pattern deviation values were worse for smokers (p < 0.001). Differences in mean defect and pattern standard deviation were not significant (p > 0.05 in both cases). The number of out-of-limits points in the total difference and pattern difference map were significantly larger for smokers. After correcting for multiple comparisons, only the differences in the upper visual hemifield were significant.
CONCLUSIONS
This pilot study suggests that even young moderate smokers show small sensitivity loss in the blue-yellow mechanism, it is statistically significant, restricted to the upper visual hemifield. This corresponds to a retinal region where literature reports a lower density of retinal ganglion cells and where, therefore, the chromatic mechanisms would be more fragile.
Topics: Adolescent; Adult; Color Perception; Humans; Linear Models; Pilot Projects; Retinal Ganglion Cells; Smokers; Visual Field Tests; Young Adult
PubMed: 32868243
DOI: 10.1016/j.optom.2020.06.006