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Translational Vision Science &... Dec 2023The purpose of this study was to determine changes in spatial and depth vision with increasing severity of keratoconus and to model the structure-function relationship...
PURPOSE
The purpose of this study was to determine changes in spatial and depth vision with increasing severity of keratoconus and to model the structure-function relationship to identify distinct phases of loss in visual function with disease severity.
METHODS
Best-spectacle corrected, monocular high-contrast visual acuity, contrast sensitivity function (CSF) and stereoacuity of 155 cases (16-31 years) with mild to advanced bilateral keratoconus was determined using standard psychophysical tests. Disease severity was quantified using the multimetric D-index. The structure-function relationship was modeled using linear, positive exponential, negative exponential, and logistic nonlinear regression equations.
RESULTS
The logistic regression model explained the highest proportion of variance for spatial vision, without bias in the residual plots (R2 ≥ 66%, P < 0.001). Visual acuity showed a distinct ceiling phase and a steeper loss rate with increasing D-index (1.8 units/D-index) in this model. The area under the CSF lacked this ceiling phase and had a shallower loss rate (0.28 units/D-index). Stereoacuity loss with D-index was poorly explained by all models tested (P ≤ 0.2). Cases with lower and bilaterally symmetric D-index had better stereoacuity (181.6-376 arc seconds) than those with higher D-index (>400 arc second); both were significantly poorer than controls (approximately 30 arc second).
CONCLUSIONS
Vision loss in keratoconus varies with the visual function parameter tested. Contrast sensitivity may be an earlier indicator of spatial vision loss than visual acuity. Depth perception is significantly deteriorated from very early stages of the disease.
TRANSLATIONAL RELEVANCE
The study outcomes may be used to forecast longitudinal vision loss in keratoconus and to apply appropriate interventions for timely preservation/enhancement of vulnerable visual functions.
Topics: Humans; Keratoconus; Visual Acuity; Structure-Activity Relationship
PubMed: 38149965
DOI: 10.1167/tvst.12.12.21 -
Ophthalmic Epidemiology Aug 2023Poor eye-health knowledge and health literacy are pervasive, contributing to worse outcomes. This study aims to examine short- and long-term eye-health knowledge...
PURPOSE
Poor eye-health knowledge and health literacy are pervasive, contributing to worse outcomes. This study aims to examine short- and long-term eye-health knowledge retention following eye-health education interventions in adults.
METHODS
Vision Detroit was an outreach vision screening program that integrated a 5-Point Teaching Intervention (5PTI), at a Southwest Community Center (SW-CC) from 2015-2017. The 5PTI consists of eye-health learning points developed to verbally educate patients. During vision screenings, eye-health knowledge tests were administered before and after 5PTI (Test 1 and Test 2, respectively). In 2016, Community Eye-Health Education Interventions (CHEI) were initiated at the SW-CC. During CHEI, bilingual healthcare students taught voluntary SW-CC members the 5PTI learning points, regardless of participant interest to attend future screenings. CHEI sessions occurred on separate dates prior to vision screening events. Test 1 and Test 2 scores were compared for all participants. Test 1 scores were compared for those who underwent CHEI prior to vision screening (CHEI positive) versus those who did not (CHEI negative).
RESULTS
Two-hundred-seventeen adult patients met inclusion criteria, with 75.8% women, 82.6% Hispanic, mean age 50.4 ± 16.2 years, 74.6% had high school or less education, and 49.2% had health insurance. Test 1 to Test 2 scores improved after 5PTI (71.2 ± 26.4% vs. 97.2 ± 9.9%, p < .00001). Forty-eight participants attended CHEI and subsequent vision screening. Test 1 scores were higher among those CHEI positive versus CHEI negative (81.1 ± 2.1% vs. 68.3 ± 3.4%, p = .0027).
CONCLUSION
Simple eye-health education interventions, delivered during vision screenings and via community-based education, can improve eye-health knowledge.
Topics: Adult; Humans; Female; Middle Aged; Aged; Male; Vision, Ocular; Vision Screening; Delivery of Health Care; Health Education
PubMed: 36177537
DOI: 10.1080/09286586.2022.2127785 -
Eye (London, England) Jan 2024After going into the etymology of the word "optotype", this article covers some tasks in ancient times that required good visual acuity (VA). Around 300 BCE, Euclid... (Review)
Review
After going into the etymology of the word "optotype", this article covers some tasks in ancient times that required good visual acuity (VA). Around 300 BCE, Euclid formulated the existence of a visual cone with a minimal visual angle at its tip. Trials to test VA appeared AD 1754. Around that time, texts were introduced by opticians in order to be able to prescribe more reliably. In the early nineteenth century, the need for VA tests in ophthalmology resulted in German and English test charts. Numerous variants emerged after the first edition of Snellen's optotypes in 1862 in The Netherlands. However, 100 years later there was still no standard optotype to reliably test VA. Multidisciplinary approaches between ophthalmology, linguistics, psychology and psychophysics improved optotypes and VA testing, which led to the more reliable LogMAR charts. Recent advances in aids and therapies for the blind and severely visually handicapped, necessitate further development of new and standardized VA tests.
Topics: Humans; Ophthalmology; Vision Tests; Visual Acuity
PubMed: 35922542
DOI: 10.1038/s41433-022-02180-6 -
Indian Journal of Ophthalmology Apr 2024This review analyzed all pertinent articles on keratoconus (KCN) and cataract surgery. It covers preoperative planning, intraoperative considerations, and postoperative... (Review)
Review
This review analyzed all pertinent articles on keratoconus (KCN) and cataract surgery. It covers preoperative planning, intraoperative considerations, and postoperative management, with the aim of providing a simplified overview of treating such patients. Preoperatively, the use of corneal cross-linking, intrastromal corneal ring segments, and topo-guided corneal treatments can help stabilize the cornea and improve the accuracy of biometric measurements. It is important to consider the advantages and disadvantages of traditional techniques such as penetrating keratoplasty and deep anterior lamellar keratoplasty, as well as newer stromal augmentation techniques, to choose the most appropriate surgical approach. Obtaining reliable measurements can be difficult, especially in the advanced stages of the disease. The choice between toric and monofocal intraocular lenses (IOLs) should be carefully evaluated. Monofocal IOLs are a better choice in patients with advanced disease, and toric lenses can be used in mild and stable KCN. Intraoperatively, the use of a rigid gas permeable (RGP) lens can overcome the challenge of image distortion and loss of visual perspective. Postoperatively, patients may need updated RGP or scleral lenses to correct the corneal irregular astigmatism. A thorough preoperative planning is crucial for good surgical outcomes, and patients need to be informed regarding potential postoperative surprises. In conclusion, managing cataracts in KCN patients presents a range of challenges, and a comprehensive approach is essential to achieve favorable surgical outcomes.
Topics: Humans; Keratoconus; Lens Implantation, Intraocular; Visual Acuity; Lenses, Intraocular; Cataract; Astigmatism; Refraction, Ocular
PubMed: 38389251
DOI: 10.4103/IJO.IJO_1241_23 -
Journal of Translational Medicine Mar 2024Global myopia prevalence poses a substantial public health burden with vision-threatening complications, necessitating effective prevention and control strategies....
BACKGROUND
Global myopia prevalence poses a substantial public health burden with vision-threatening complications, necessitating effective prevention and control strategies. Precise prediction of spherical equivalent (SE), myopia, and high myopia onset is vital for proactive clinical interventions.
METHODS
We reviewed electronic medical records of pediatric and adolescent patients who underwent cycloplegic refraction measurements at the Eye & Ear, Nose, and Throat Hospital of Fudan University between January 2005 and December 2019. Patients aged 3-18 years who met the inclusion criteria were enrolled in this study. To predict the SE and onset of myopia and high myopia in a specific year, two distinct models, random forest (RF) and the gradient boosted tree algorithm (XGBoost), were trained and validated based on variables such as age at baseline, and SE at various intervals. Outputs included SE, the onset of myopia, and high myopia up to 15 years post-initial examination. Age-stratified analyses and feature importance assessments were conducted to augment the clinical significance of the models.
RESULTS
The study enrolled 88,250 individuals with 408,255 refraction records. The XGBoost-based SE prediction model consistently demonstrated robust and better performance than RF over 15 years, maintaining an R exceeding 0.729, and a Mean Absolute Error ranging from 0.078 to 1.802 in the test set. Myopia onset prediction exhibited strong area under the curve (AUC) values between 0.845 and 0.953 over 15 years, and high myopia onset prediction showed robust AUC values (0.807-0.997 over 13 years, with the 14th year at 0.765), emphasizing the models' effectiveness across age groups and temporal dimensions on the test set. Additionally, our classification models exhibited excellent calibration, as evidenced by consistently low brier score values, all falling below 0.25. Moreover, our findings underscore the importance of commencing regular examinations at an early age to predict high myopia.
CONCLUSIONS
The XGBoost predictive models exhibited high accuracy in predicting SE, onset of myopia, and high myopia among children and adolescents aged 3-18 years. Our findings emphasize the importance of early and regular examinations at a young age for predicting high myopia, thereby providing valuable insights for clinical practice.
Topics: Adolescent; Child; Child, Preschool; Humans; Myopia; Refraction, Ocular
PubMed: 38494492
DOI: 10.1186/s12967-024-05075-0 -
Vision Research Jul 2024Studies in animal models and humans have shown that refractive state is optimized during postnatal development by a closed-loop negative feedback system that uses... (Review)
Review
Studies in animal models and humans have shown that refractive state is optimized during postnatal development by a closed-loop negative feedback system that uses retinal image defocus as an error signal, a mechanism called emmetropization. The sensor to detect defocus and its sign resides in the retina itself. The retina and/or the retinal pigment epithelium (RPE) presumably releases biochemical messengers to change choroidal thickness and modulate the growth rates of the underlying sclera. A central question arises: if emmetropization operates as a closed-loop system, why does it not stop myopia development? Recent experiments in young human subjects have shown that (1) the emmetropic retina can perfectly distinguish between real positive defocus and simulated defocus, and trigger transient axial eye shortening or elongation, respectively. (2) Strikingly, the myopic retina has reduced ability to inhibit eye growth when positive defocus is imposed. (3) The bi-directional response of the emmetropic retina is elicited with low spatial frequency information below 8 cyc/deg, which makes it unlikely that optical higher-order aberrations play a role. (4) The retinal mechanism for the detection of the sign of defocus involves a comparison of defocus blur in the blue (S-cone) and red end of the spectrum (L + M-cones) but, again, the myopic retina is not responsive, at least not in short-term experiments. This suggests that it cannot fully trigger the inhibitory arm of the emmetropization feedback loop. As a result, with an open feedback loop, myopia development becomes "open-loop".
Topics: Humans; Myopia; Emmetropia; Retina; Refraction, Ocular; Animals; Feedback, Physiological
PubMed: 38705024
DOI: 10.1016/j.visres.2024.108402 -
Ophthalmic & Physiological Optics : the... Sep 2023Vision standards for driving are typically based on visual acuity, despite evidence that it is a poor predictor of driving safety and performance. However, visual motion...
INTRODUCTION
Vision standards for driving are typically based on visual acuity, despite evidence that it is a poor predictor of driving safety and performance. However, visual motion perception is potentially relevant for driving, as the vehicle and surroundings are in motion. This study explored whether tests of central and mid-peripheral motion perception better predict performance on a hazard perception test (HPT), which is related to driving performance and crash risk, than visual acuity. Additionally, we explored whether age influences these associations, as healthy ageing impairs performance on some motion sensitivity tests.
METHODS
Sixty-five visually healthy drivers (35 younger, mean age: 25.5; SD 4.3 years; 30 older adults, mean age: 71.0; SD 5.4 years) underwent a computer-based HPT, plus four different motion sensitivity tests both centrally and at 15° eccentricity. Motion tests included minimum displacement to identify motion direction (D ), contrast detection threshold for a drifting Gabor (motion contrast), coherence threshold for a translational global motion stimulus and direction discrimination for a biological motion stimulus in the presence of noise.
RESULTS
Overall, HPT reaction times were not significantly different between age groups (p = 0.40) nor were maximum HPT reaction times (p = 0.34). HPT response time was associated with motion contrast and D centrally (r = 0.30, p = 0.02 and r = 0.28, p = 0.02, respectively) and with D peripherally (r = 0.34, p = 0.005); these associations were not affected by age group. There was no significant association between binocular visual acuity and HPT response times (r = 0.02, p = 0.29).
CONCLUSIONS
Some measures of motion sensitivity in central and mid-peripheral vision were associated with HPT response times, whereas binocular visual acuity was not. Peripheral testing did not show an advantage over central testing for visually healthy older drivers. Our findings add to the growing body of evidence that the ability to detect small motion changes may have potential to identify unsafe road users.
Topics: Humans; Aged; Adult; Motion Perception; Visual Acuity; Visual Perception; Vision, Ocular; Reaction Time; Automobile Driving
PubMed: 37306319
DOI: 10.1111/opo.13180 -
Survey of Ophthalmology 2024In phakic patients Descemet stripping automated endothelial keratoplasty (DSAEK) or Descemet membrane endothelial keratoplasty (DMEK) are frequently combined with... (Review)
Review
In phakic patients Descemet stripping automated endothelial keratoplasty (DSAEK) or Descemet membrane endothelial keratoplasty (DMEK) are frequently combined with phacoemulsification and intraocular lens (IOL) implantation (triple procedure). This surgery might cause a refractive shift difficult to predict. Early DMEK and DSAEK results have shown a tendency toward a hyperopic shift. Myopic postoperative refraction is typically intended to correct this postoperative refractive defect and to bring all eyes as close to emmetropia as possible. We sought to understand the mechanism underlying the hyperopization and to identify predictive factors for poorer refractive outcomes, the most suitable target refraction and IOL calculation methods in patients undergoing combined cataract extraction and lamellar endothelial corneal transplantation (DSAEK or DMEK) for endothelial dysfunctions. Of the 407 articles analyzed, only 18 were included in the analysis. A myopic target between -0.50 D and -0.75 was the most common (up to -1.50 for DSAEK triple procedures), even though no optimum target was found. Hyperopic surprises appeared more frequently in corneas that were flatter in the center than in the periphery (oblate posterior profile). Among the numerous IOL calculation formulas, there was no apparent preference.
Topics: Humans; Refraction, Ocular; Descemet Stripping Endothelial Keratoplasty; Lens Implantation, Intraocular; Phacoemulsification; Visual Acuity
PubMed: 38309315
DOI: 10.1016/j.survophthal.2024.01.003 -
European Journal of Ophthalmology Mar 2024Practical advancements in phacoemulsification techniques and intraocular lenses and the wide availability of phacoemulsification machines have led refractive lens...
Practical advancements in phacoemulsification techniques and intraocular lenses and the wide availability of phacoemulsification machines have led refractive lens exchange (RLE) to increase in popularity. Ethical boundaries in RLE have subsequently been pushed to include patients at higher risk of complications. In this editorial, we consider RLE outcomes and complications per type of refractive error, together with preoperative, intraoperative and postoperative ethical obligations for refractive surgeons. In the conclusions section, we propose an algorithm for ethics-guided indications to RLE.
Topics: Humans; Visual Acuity; Astigmatism; Lens Implantation, Intraocular; Refraction, Ocular; Lenses, Intraocular; Phacoemulsification
PubMed: 38062638
DOI: 10.1177/11206721231218909 -
Optometry and Vision Science : Official... Dec 2023The Waggoner PIP24 is a pseudoisochromatic test with a pattern similar to the Ishihara test. This study determined that the W-PIP24 can be used clinically to yield...
SIGNIFICANCE
The Waggoner PIP24 is a pseudoisochromatic test with a pattern similar to the Ishihara test. This study determined that the W-PIP24 can be used clinically to yield screening results (or sensitivity and specificity) comparable with the Ishihara.
PURPOSE
This study aimed to determine whether the W-PIP24 is equivalent to the Ishihara 38 edition pseudoisochromatic test in detecting red-green color vision defects. Also, the performance of each plate of the W-PIP24 in detecting the color vision defects relative to the Ishihara test was determined.
METHODS
Sixty-three individuals with congenital red-green color vision defects and 57 with normal trichromacy were recruited. Participants were tested with both the Ishihara and W-PIP24. The first-order agreement coefficients were calculated for the Ishihara and W-PIP24. The results were also analyzed using specificity, sensitivity, efficiency, and predictive pass and fail values.
RESULTS
The agreement between the W-PIP24 and Ishihara test using the recommended criterion of using all plates was perfect. The sensitivity, specificity, predictive pass, and predictive fail were 1.00 (95% confidence interval, 0.94 to 1.00).
CONCLUSIONS
This study showed that the W-PIP24 using a failure criterion of three or more errors on screening plates 1 to 15 is equivalent to the Ishihara test while screening for red-green color vision deficiency using a failure criterion of three or more errors on screening plates 1 to 17 of the Ishihara 38 edition.
Topics: Humans; Color Vision Defects; Color Perception Tests; Color Vision; Sensitivity and Specificity; Color Perception
PubMed: 38019937
DOI: 10.1097/OPX.0000000000002087