Ophthalmic and Physiological Optics最新文献

Purpose: Individuals with convergence insufficiency (CI) encounter challenges in turning their eyes inward during near work. It is unclear how this relates to brain structural and functional alterations. This study aimed to explore the neural mechanism underlying CI using multimodal brain magnetic resonance imaging (MRI).

Methods: Thirty-four CI participants and 35 healthy controls (HC) were recruited, who underwent visual examinations and brain MRI scanning. Structural MRI data were analysed to calculate cortical thickness, volume and surface area. Fractional amplitude of low-frequency fluctuation (fALFF) and seed-based functional connectivity were obtained from resting-state functional MRI data. The brain structural and functional metrics were compared between the two groups followed by correlation analyses between clinical measurements and significant brain features.

Results: Relative to HC, individuals with CI had lower grey matter volume (GMV) and surface area in the right frontal eye fields, parietal eye fields and left medial orbitofrontal cortex, higher GMV and surface area in the right middle frontal and inferior temporal gyri and higher fALFF of the left cerebellum and functional connection between bilateral cerebellums. GMV of the right middle frontal gyrus and fALFF in the left cerebellum were positively correlated with the near point of convergence in all participants.

Conclusions: Lower structural metrics in the visual and oculomotor cortices and higher functional activity in the cerebellum may underpin convergence dysfunction and visual fatigue, while higher structural metrics in the right middle frontal and inferior temporal gyri reflect partial compensation for the visual and oculomotor cortex defects, thereby maintaining attention and parallax information processing. This study may enhance understanding of the neural mechanism of CI by revealing the impact of abnormal visual experiences of CI on the brain with disassociated structural and functional alterations in the vergence system.

Introduction: Multisegment (MS) spectacles are intended to slow myopia progression by modifying images falling on the peripheral retina. Some published optical treatments of these lenses assume normal incidence of light at the surfaces, but images falling on the peripheral retina are usually associated with oblique ray pencils. Here, we model representative images of point objects produced by the Hoya MiyoSmart MS spectacle lens when oblique ray pencils are used.

Methods: Various imaging aspects of the MS lens alone and in combination with a suitable accommodating eye model for a 4D myope were evaluated using the Optical Design program Ansys Zemax OpticStudio. Configurations studied included object points at vergences of zero and -4 D, with the objects being either on the lens axis or at a field angle of about 30°. The effect on foveal vision of rotating the axis of the eye with respect to that of the lens was also considered. Images of point objects were described in terms of spot diagrams and fast Fourier transform point-spread functions.

Results: Symmetry and overall optical quality of images decreased with the obliquity of the ray pencils, due to the increased off-axis aberrations of the lens and the eye. Images of near object points were strongly affected by the level of accommodation: optimal retinal image quality occurred when accommodation brought the carrier lens focus close to the retina, rather than that of the lenslets.

Conclusions: Attempts to understand why MS lenses slow myopia progression need to consider the way in which through-focus retinal image quality changes with obliquity of the ray pencils across the visual field and the possible effects of ocular accommodation.

Purpose: This study evaluated newly designed tests to measure near heterophoria, comparing them to the Maddox Wing and Howell card, and assessed whether accommodative responses differed between the different heterophoria test targets.

Methods: Near horizontal heterophoria of 20 visually normal young adults was measured using the Maddox Wing, Howell Card and two versions of a newly designed Huddersfield Heterophoria Test (HHT) card. The HHT cards are based on the Prentice method, either with or without an additional spatially defined grating superimposed on the scale. The addition of a spatially defined grating has been suggested to control accommodation better. A single examiner was used to take measurements on two separate occasions, presenting each test in a random order. Monocular accommodative responses to each heterophoria target were also obtained in a separate session by another examiner.

Results: Heterophoria measurements between the four tests were not significantly different, neither clinically nor statistically. Differences in test-retest measurements between test and retest conditions were small and not significantly different. Mean accommodative responses were also not significantly different between the test targets.

Conclusions: Differences in target configurations in the Maddox Wing, Howell card or new HHT cards did not influence accommodative responses in a sample of young adults. The newly designed HHT cards (or other variations of the Prentice method) may be used to measure near horizontal heterophoria in a young adult population either with or without additional horizontal lines superimposed on the scale.

Purpose: The purpose of this study was to compare the perception and understanding of the information provided by ChatGPT regarding myopia among optometry students, optometrists undertaking a Master degree and practicing optometrists.

Methods: This was a cross-sectional descriptive study using a structured questionnaire distributed via Wooclap to 225 participants (125 optometry students, 21 Masters student and 79 practicing optometrists). All participants evaluated the responses generated by ChatGPT Version 4.0 using a five-point scale: very poor, poor, acceptable, good and very good. Data were analysed using SPSS, applying descriptive analysis and chi-squared tests to assess the significance of differences observed between the groups.

Results: Practicing optometrists, with an average age of 39.7 ± 11.0 and 15.2 ± 7.5 years of professional experience, rated the information provided by ChatGPT on myopia complications more positively than the optometry and Masters student, highlighting the importance of clinical experience (p < 0.001). Alternatively, this may indicate a difference in awareness, knowledge and training, with younger students potentially being more speculative in their evaluations. The perceptions about myopia prevention among the groups were similar (p = 0.28). At the same time, the perceptions of the effectiveness of treatments such as contact lenses and pharmaceutical agents showed differences, with optometrists rating these treatments more positively (p < 0.001 and p = 0.004, respectively).

Conclusions: This study showed differences in the perception and interpretation of the information provided by ChatGPT about myopia depending on the level of education. While AI plays an important role in education, practicing optometrists trust the information extracted by ChatGPT more than optometry students.

Introduction: Previous research suggests that the electroretinogram (ERG) is reduced and delayed in non-pathological myopia. However, the invasive nature of the electrode and cumbersome equipment required has prevented the widescale uptake of ERG measures. This study investigated whether previously reported changes to the ERG response in myopia are also observable when measured using non-invasive skin electrodes and a hand-held ERG device.

Method: Monocular flash ERGs were measured using the RETeval® device according to the 'ISCEV 6 Step Dark First cd' protocol in 46 participants with non-pathological myopia (spherical equivalent refraction [SER] -0.50 to -11.25 D, median -3.75 D, median axial length [AL] 25.4 mm) and 47 non-myopic controls (SER +2.00 to -0.25 D, median +1.00 D, median AL 23.6 mm). Measures were performed under pupil mydriasis with Sensor Strip skin electrodes.

Results: The median implicit time for all dark-adapted (DA) components was longer among myopes. Following Holm-Bonferroni correction, this difference reached statistical significance (p < 0.05) for the DA 3.0 A-wave, DA 10.0 A-wave and B-waves, and DA Oscillatory potentials 1 and 2. There were no significant differences between median light-adapted (LA) implicit times nor response amplitudes between refractive groups. For all DA components, there was a significant, positive correlation between AL and implicit time (all p < 0.05).

Conclusions: The RETeval®, used with skin electrodes, did not detect the reduction in ERG amplitude reported in myopic eyes using traditional ERG setups, potentially due to high inter-subject variability and/or anatomical confounders associated with the use of a skin electrode. The RETeval® with skin electrodes did detect subtle delays to DA implicit times previously reported in myopia, with a positive relationship observed between AL and implicit time for all DA components. In contrast, no significant differences were observed for LA implicit times, which may indicate underlying differences in the dark-adaptation process and/or scotopic visual pathways in myopia.

Objective: The present study evaluated the correlation between ocular sagittal height and lens sagittal depth, specifically focusing on the sagittal difference (δ-sag) that defines an optimal lens fit.

Methods: The ocular sagittal height (spanning a 14.2-mm chord in the ocular surface flattest meridian) of 30 subjects was measured using the Oculus Pentacam HR. Participants were fitted with eight different standard daily disposable soft contact lenses, each having a known sagittal depth. To evaluate the fit, both objective methods (using ImageJ software) and subjective assessments (by two experienced eye care professionals [ECPs]) were employed. Descriptive statistics were obtained for different δ-sag, and correlations and a regression model were applied to determine the δ-sag range indicative of a satisfactory lens fit, based on the objective and subjective evaluations.

Results: The δ-sag achieved in most cases ranged between 200 and 600 μm. Participants reported high comfort levels independently of δ-sag (H = 8.99; p = 0.25) and type of contact lens (χ² = 1.47; p = 0.98). Significant correlations were found between δ-sag and objective assessments of lens centration (inferior, nasal and temporal) and movement (nasal lag). The regression model, based on the subjective assessment conducted by the ECPs, yielded a δ-sag of between 120 and 280 μm for a score considered as good.

Conclusions: Objective and subjective assessments showed significant associations with δ-sag. A standard cast-moulded disposable soft contact lens whose sagittal depth exceeded the ocular sagitta corresponding to the chord equivalent to the total contact lens diameter by 120-280 μm would most likely result in an optimal fit. These findings could help improve fitting accuracy and reduce dropout rates, thereby enhancing patient experience and ocular health.

Purpose: To evaluate the sensitivity and specificity of the PlusOptix S12C device in detecting amblyopia risk factors (ARFs) in children aged 2-7 years, in accordance with the 2020 Israeli Ministry of Health (MOH) directives and the 2021 American Association for Pediatric Ophthalmology and Strabismus (AAPOS) guidelines.

Methods: A cross-sectional, observational study was conducted at a tertiary care hospital. Children presenting for vision testing were screened using the PlusOptix S12C device, and results were compared with the gold standard cycloplegic refraction and cover test. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for the overall population and subpopulations based on ARFs.

Results: A total of 196 children aged 24-84 months were screened (46.4% boys, mean age: 56.94 ± 17.52 months). The PlusOptix S12C demonstrated an overall sensitivity and specificity of 85.5% and 82.3%, respectively. Sensitivity for hyperopia (>4.00 D) was lower (47.7%), while specificity was 81.7%. For strabismus (>8 Δ), sensitivity and specificity were 67.8% and 91.1%, respectively. The device failed to produce readings in 21.9% of children, primarily those with significant refractive errors or strabismus.

Conclusions: The PlusOptix S12C demonstrated good overall sensitivity and specificity for detecting ARFs, making it a valuable tool for large-scale paediatric vision screening, including in very young children. However, its inherent limitations in detecting high hyperopia and strabismus, combined with the high prevalence of these conditions in the untestable group, highlight the need for supplementary evaluation. Children who receive a 'no result' or 'unable-to-read' outcome on the device should be referred for a full examination, including cycloplegic refraction, to ensure ARFs are not missed. While the device aligns well with the 2021 AAPOS and MOH guidelines, careful attention to its limitations in high-risk subpopulations is essential to optimise screening efficacy and outcomes.

Purpose: To quantify objectively the influence of brightness artefacts inherent in Scheimpflug tomography on corneal densitometry (CD) estimates.

Methods: Fifty-seven healthy participants aged 30.9 ± 13.7 years (range 17-60 years) were examined with a Ziemer Galilei G2 Scheimpflug tomographer. Images were automatically segmented to isolate the cornea, iris, crystalline lens and corneoscleral lateral brightness regions. CD was calculated as the corneal mean pixel intensity (MPI). Statistical analysis explored the relationship between brightness artefacts and CD across different corneal layers, while also considering age and biometric parameters such as anterior chamber depth and pupil size.

Results: Brightness artefacts accounted for 6.56 ± 1.93% of the pixels in the images, with lateral brightness being the largest source of noise (4.19 ± 0.97%). A strong positive correlation was found between CD and overall brightness artefacts (r = 0.57, p < 0.001). Age was also significantly correlated with both CD (r = 0.65, p < 0.001) and brightness (r = 0.29, p = 0.01). Mediation analysis revealed that age accounts for 60.0% of CD variability, while brightness artefacts contributed 40.0%. Brightness artefacts had the strongest effect on the corneal periphery beyond 7.5 mm as well as the stromal layer.

Conclusion: Brightness artefacts significantly influence CD estimates, particularly in the peripheral cornea. Accurate quantification of these artefacts is essential for proper clinical assessment of corneal transparency, especially in older populations. Future research should focus on identifying the specific sources of artefacts to refine CD measurement techniques.

Purpose: To report the repeatability and accuracy of viewing distance and ambient illumination measured with the Vivior and Clouclip wearable sensors in a controlled laboratory setting and while young adults performed different near visual tasks.

Methods: For Study 1, viewing distance and ambient illumination were measured repeatedly for 2 days with two sensors mounted on a mannequin. Results were compared with standard measures (ruler, lux meter) using linear regression and Bland-Altman analysis. In Study 2, viewing distances were captured in 13 young adults while they performed four near tasks for 20 min each (reading a printed article, reading an article on an iPad, typing on a laptop or watching videos on an iPad) under three illuminations (500, 250 and 25 lux). Results were compared between the devices and with a standard ruler and differences tested statistically using ANOVA and Tukey's multiple comparison tests.

Results: In Study 1, a positive linear relationship was observed between viewing distances measured by each sensor and the standard ruler (mean [SD] difference of -0.12 cm [0.23] for Vivior, -0.18 cm [0.51] for Clouclip), with good repeatability (mean [SD] difference between 2 days was 0.02 cm [0.24] for Vivior, -0.14 cm [0.35] for Clouclip). A positive linear relationship was also observed between illumination measured by each sensor and the luxmeter (mean [SD] difference of -16.85 lux [325.5] for Vivior, 39.12 lux [335.6] for Clouclip). In Study 2, the viewing distances during the four near tasks were not significantly different between the three methods used. Shorter working distances were measured with all methods when reading a printed article compared to typing on a laptop and watching a video on the iPad (all p < 0.05).

Conclusion: Vivior and Clouclip are recommended for real-time capture of near vision duration, distance and light exposure in future studies aiming to understand the effect of habitual visual environment.

Purpose: Part 1 of the study investigated image quality associated with oblique incidence of light on a multisegment lens (Hoya MiyoSmart) intended to treat myopia development. Part 2 investigates power corrections associated with oblique incidence.

Methods: Modelling and ray tracing were carried out with lenses of -4 D distance power and, to a lesser extent, +0.25 D. Ray tracing simulations were done for the lens by itself, an eye model by itself and the combination. These simulations were for the static situation of peripheral vision when the eye looks through the lens centre and for central (foveal) vision when the eye rotates to look at objects away from the lens optical axis. The outcome was power correction of the optics, that is, the difference between the nominal power of the distance correction provided by the carrier lens under specific conditions and the actual power. This was determined across the field to about 45° and across the pupil for certain field angles. Most investigations were performed for distance vision, but some were for near objects with an accommodating version of the model eye.

Results: Ignoring intended multisegment effects, the quality of optics associated with peripheral vision was poor. There was considerable astigmatism (cylinder) across the field and high variation in astigmatism across the pupil. The added effects of the lens and eye were similar to those of their combination. For the accommodated eye model with an object at 250 mm, results were similar to those obtained with the unaccommodated model viewing a distant object. For foveal vision with the rotating eye, optics were relatively good with lower levels of astigmatism than for peripheral vision.

Conclusion: The results of Part 1, finding considerable effects of the obliquity of incidence associated with peripheral vision and with foveal vision for the rotating eye, were supported by the power corrections.