Ophthalmic and Physiological Optics最新文献

Purpose: The aim of this study was to investigate, using a power vector approach, whether corneal astigmatism follows a mirror symmetry pattern considering both the magnitude and axis, and whether age, sex and spherical equivalent refractive error can influence the pattern.

Methods: The IOLMaster 700 optical biometer was used to measure the radii of curvature of the anterior corneal surface. Refractive error was determined by non-cycloplegic subjective refraction. Descriptive statistical analyses and inferential logistic regression were applied over the dichotomous variable of mirror symmetry using J₀ and J₄₅ power vector components. An evaluation was carried out based on the subject's age, sex and spherical equivalent refractive error.

Results: A total of 2974 Caucasian adults were evaluated. This cross-sectional study revealed that axis orientation follows the isorule symmetry pattern, and in terms of both magnitude and axis orientation, mirror symmetry was present in 70.9% of cases. Age, sex and spherical equivalent refractive error were not significant factors and did not contribute to the clinical improvement of the model despite its statistical significance (refractive error, p = 0.001; age and sex, p = 0.23 and 0.36, respectively).

Conclusions: Among an adult Caucasian population, the prevalence of corneal astigmatism mirror symmetry was 70.9% and isorule symmetry was the most common pattern considering axis orientation only. The inclusion of age, sex and spherical equivalent refractive error did not improve the model.

Purpose: To propose a novel artificial intelligence (AI)-based virtual assistant trained on tabular clinical data that can provide decision-making support in primary eye care practice and optometry education programmes.

Method: Anonymised clinical data from 1125 complete optometric examinations (2250 eyes; 63% women, 37% men) were used to train different machine learning algorithm models to predict eye examination classification (refractive, binocular vision dysfunction, ocular disorder or any combination of these three options). After modelling, adjustment, mining and preprocessing (one-hot encoding and SMOTE techniques), 75 input (preliminary data, history, oculomotor test and ocular examinations) and three output (refractive, binocular vision status and eye disease) features were defined. The data were split into training (80%) and test (20%) sets. Five machine learning algorithms were trained, and the best algorithms were subjected to fivefold cross-validation. Model performance was evaluated for accuracy, precision, sensitivity, F1 score and specificity.

Results: The random forest algorithm was the best for classifying eye examination results with a performance >95.2% (based on 35 input features from preliminary data and history), to propose a subclassification of ocular disorders with a performance >98.1% (based on 65 features from preliminary data, history and ocular examinations) and to differentiate binocular vision dysfunctions with a performance >99.7% (based on 30 features from preliminary data and oculomotor tests). These models were integrated into a responsive web application, available in three languages, allowing intuitive access to the AI models via conventional clinical terms.

Conclusions: An AI-based virtual assistant that performed well in predicting patient classification, eye disorders or binocular vision dysfunction has been developed with potential use in primary eye care practice and education programmes.

Purpose: Visual acuity (VA) is a primary outcome measure that defines the success of clinical interventions for retinal diseases such as age-related macular degeneration (AMD) or diabetic macular oedema (DME). These conditions can lead to the presence of subretinal fluid, causing substantial photoreceptor layer elevation. Hyperopic defocus then occurs, affecting the VA measurements. In this study, we simulated the induced hyperopic shift for real-world values of photoreceptor layer elevation and measured the effect on VA measurements.

Methods: To simulate the hyperopic shift, we used a four-surface eye model. To measure the effect of defocus on VA, normally sighted adults (N = 44, mean [SD] age = 32 [13.0] year, range: 21-71 year) performed four test conditions, that is, defocus of 0.00, +0.75, +1.50 and +2.25 D. For each subject, mean VA and SD obtained from a cumulative normal fit to the VA data provided the coefficient of variation (CV) and 95% confidence interval (CI).

Results: Refractive error induced by photoreceptor layer elevation was maximum for hyperopic error conditions, followed by emmetropic and myopic refractive error conditions. The 76% threshold VA worsened with increasing defocus conditions. The 95% CI was significantly larger for +0.75, +1.50 and +2.25 D defocus compared to no defocus (p = 0.04, 0.02 and 0.01, respectively). The CI for the +2.25 D defocus condition was larger (3-10 letters) compared with no defocus (3-6 letters).

Conclusions: Photoreceptor layer elevation causes a hyperopic shift sufficient for clinically meaningful changes: worse VA and more variable measurements.

This study was aimed at assessing the effects of a 6-week intervention within a training environment that uses special lighting conditions targeted to slow down the visual processing speed of visual and visuomotor performance in professional soccer players. Twenty-four soccer players (age = 21.8 ± 4.8 years, 50% women) from the under 18 and under 23 men's teams, and 1st Women's team of the Sunderland Association Football Club participated in this study. Participants were randomly assigned to the intervention and control groups, with the intervention group performing 2-weekly 30-min sessions of specific soccer tasks with specific lighting conditions using the Okkulo system (Okkulo™, okkulo.com), whereas the control group performed the same training under normal lighting conditions. The intervention group showed significant improvements in dynamic visual acuity (p < 0.001), recognition time (p = 0.002), sensory reaction time (p < 0.001), motor reaction time (p = 0.002) and peripheral identification accuracy (p < 0.001), whereas no significant effects were obtained for stereopsis (p = 0.05), peripheral identification speed (p = 0.17) and anticipation (p = 0.22). In conclusion, a 6-week training intervention using the Okkulo system improved several visual and visuomotor skills in professional soccer players. Future studies will assess the transfer effects of using this technology to on-field performance.

Purpose: To compare the parameters and indices of a novel swept-source optical coherence tomography device (SS-OCT, ANTERION) with those of a rotating Scheimpflug camera (RSC)-based tomograph (Pentacam) in normal and keratoconic (KC) eyes.

Methods: This prospective, monocentric, cross-sectional study included individuals with unoperated normal and KC eyes, selecting one eye per subject. Ectasia-specific parameters analysed with the SS-OCT were difference in mean keratometry (K_mean) in the inferior and superior meridians, maximum keratometry value (K_max), elevation of the posterior surface at the thinnest point, screening corneal objective risk of ectasia (SCORE) and thinnest point thickness. With the RSC, parameters determined were Belin/Ambrosio total deviation value (BAD-D), index of height decentration and index of vertical asymmetry. KC classification with the SS-OCT was based on the anterior and posterior radii of curvature and thinnest point thickness according to the ABCD classification of the RSC system.

Results: This study included 117 individuals with healthy eyes and 335 eyes with KC. The indices with the highest diagnostic discriminatory ability between the two cohorts were SCORE, difference of K_mean in the inferior and superior meridians and posterior elevation of the thinnest point (SS-OCT), as well as the index of height decentration, index of vertical asymmetry and BAD-D (RSC). The classifications using SS-OCT defined mild-stage KC as K_max, posterior elevation of the thinnest point and thinnest point thickness as ≤50.9 D, ≤30 and ≥472 μm, respectively. Moderate stage values were 51-55.9 D, 31-69 and 471-438 μm, respectively, while respective advanced stage were ≥56 D, ≥70 and ≤437 μm.

Conclusion: The diagnostic capabilities for both devices were found to be comparable. KC classification using SS-OCT can be independently based on the anterior surface, posterior surface and corneal thickness.

Purpose: Cerebral visual impairment (CVI) is a brain-based condition which can be exacerbated by clutter. This study aimed to explore the relation between clutter and visual fatigue in children with CVI and evaluate the effectiveness of clutter algorithm metrics in assessing visual clutter in photographs of children's play areas and the relation to visual fatigue.

Methods: Visual clutter was measured using algorithmic metrics, subjective observations by a clinical researcher (who also observed visual fatigue) and a Qualtrics survey.

Results: Seventy-two children (mean performance age = 7 years 4 months) were included. Visual fatigue was present in over 90% of children. Results revealed a relation between clutter and visual fatigue observations (r_s = 0.29; p = 0.01) and between visual clutter observations from researchers and Qualtrics participants (r_s = 0.32; p = 0.02). Certain metrics were correlated with visual clutter observations (r_s ranging from -0.30 to 0.51, p-values ranging from <0.001 to 0.03), but not with visual fatigue.

Conclusions: Children with CVI presented with visual fatigue, particularly in cluttered environments. Therefore, parents, caregivers, teachers and clinicians should be attentive to visual fatigue signs, as early recognition and intervention can help address the child's needs more effectively. Algorithms that effectively quantify visual clutter are valuable tools that can be integrated to enhance the assessment of clutter and its relation with visual fatigue to advance CVI research methodology. However, a clinician is required to assess visual fatigue and to obtain detailed information on environmental clutter, which algorithms alone may not fully capture. Finally, we recognise that visual fatigue and the impact of clutter should be integrated into psychoeducation and the comprehensive assessment of individuals with CVI.

The Maddox rod is a staple in the assessment of strabismus. However, its optics mechanism is puzzling. How is it that an orthogonal line focus is formed? Surprisingly, few texts offer an explanation and those that do either provide insufficient detail, contain misleading information or are difficult to follow. There is a prevalent misconception that multiple cylinders are required for the orthogonal line focus to appear. However, this is untrue; Maddox himself only used a single cylinder when he first described the phenomenon. Herein, we review the optics explanations provided in a sample of texts and offer an accurate explanation using the biplanar principle of astigmatic refraction.

Purpose: To explore the longitudinal changes in retinal and choroidal thickness and their relation with the onset of type 1 diabetes mellitus (T1DM) in children.

Methods: Thirty-eight children with T1DM and 71 healthy controls were included in this 3-year longitudinal study. Ophthalmic and systemic examinations were conducted on each participant. Retinal and choroidal thickness were measured by optical coherence tomography. Baseline values and changes in retinal and choroidal thickness were compared with DR onset, diabetics without DR and healthy controls. Logistic regression was used to explore the association with DR development.

Results: Six children developed DR during the follow-up period (15.79%) and five of them developed microaneurysms in the parapapillary temporal quadrant. During follow-up, greater retinal thickening occurred in subjects with DR compared with diabetic participants without DR (p = 0.03) and healthy controls (p = 0.02) in the parapapillary outer temporal section. Compared with the control group, greater retinal thickening was observed in DR subjects in the averaged parapapillary outer ring (p = 0.01), the macular inner temporal section (p = 0.03) and several macular sections (all p < 0.05). Additionally, greater retinal thickening was observed in several parapapillary regions in non-DR T1DM participants compared with healthy controls (all p < 0.05). The thickness change in the outer temporal parapapillary section was independently associated with DR onset (OR = 1.33, 95% CI 1.01-1.73, p = 0.04).

Conclusion: Children with T1DM showed a significant or a trend of increasing retinal and choroidal thickness compared with normal controls over a 3-year period. The change of retinal thickness in the parapapillary outer temporal section was associated with the development of DR in children with T1DM, suggesting that it could serve as a biomarker for predicting and screening DR in these individuals.

Purpose: To assess longitudinal changes in optical quality across the periphery (horizontal meridian, 60°) in young children who are at high (HR) or low risk (LR) of developing myopia, as well as a small subgroup of children who developed myopia over a 3-year time frame.

Methods: Aberrations were measured every 6 months in 92 children with functional emmetropia at baseline. Children were classified into HR or LR based on baseline refractive error and parental myopia. Zernike polynomials were calculated for 4 mm pupils, accounting for the elliptical shape of the pupil in the periphery. Various metrics were computed, including Strehl Ratios with only high-order aberrations (HO-SR). Primary spherical aberration (SA), horizontal coma and defocus were also analysed given their relevance in emmetropisation. The areas under the image quality metrics for various regions of interest were computed.

Results: HO-SR were higher in children at HR and children with myopia, even when SA was removed from the Strehl Ratio (SR) calculation. SA was less positive in children at HR and children with myopia. Defocus was more negative in children at HR and children with myopia at all eccentricities and was even more negative when computed relative to the fovea, an effect that increased in the mid periphery. Relative peripheral defocus also became more negative over time in children at HR and children with myopia at the mid temporal retina. The other aberrations showed no significant changes in time overall.

Conclusions: This longitudinal study showed differences in HO-SR, SA and defocus in the central and near-peripheral retina (±20°) of young children at HR before they develop myopia compared with children at LR for myopia. The results may indicate these eccentricities are significant in providing signals for emmetropisation. The small changes noted over time may indicate that the differences are a cause of myopia development.