Ophthalmic and Physiological Optics最新文献

Purpose: To assess the ability of the Dolphin air-pulse aesthesiometer to present multiple stimuli, which are separated temporally (in sequence) or spatially (simultaneously).

Methods: Two studies were performed to explore the cooling effects induced by double air-puff stimuli generated by a novel aesthesiometer composed of two micro-blower integrated units. The stimuli were delivered sequentially or simultaneously at the same or different spatial locations to an in vitro eye model monitored using thermography. The model eye was based on a 2-cm LED dome light mounted on a circuit board with an 8-V supply producing a baseline 32°C temperature. Single and repeated air-pulse stimuli varying in intensity, duration, inter-stimulus delay and stimulus location were presented to the model. The cooling effect produced was observed using a thermal camera and quantified using image analysis software.

Results: The instrument can deliver single stimuli, repeated single stimuli with a variable time delay or multiple stimuli either simultaneously or with a time delay between them. The thermal effects of stimuli were evaluated by measuring (relative to pre-stimulus baseline) the local temperature change and the diameter of the model eye surface region with ≥1°C reduction. Repeated stimuli at the same location produced a significantly greater effect than a single stimulus of the same intensity (larger area of cooling after the second stimulus compared to the first [|M|{SE} = 1.48 mm {0.06}, p < 0.001]). Spatially separated stimuli produced separate cooling zones, with the amount of cooling relative to stimulus intensity (rm-ANOVA, F_2,8 = 276.01, p < 0.001, $\omega$ ² = 0.96).

Conclusions: The combined use of two micro-blower units allows increased options for modification of stimulus intensity and timing of delivery that enables the production of alternative stimulus presentations and intensity compared to a single stimulus. This adaptability may enable future in vivo study of corneal sensory nerve summation.

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.

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: 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.

Introduction: To evaluate the long-term effect of corneal transplantation on mental health outcomes and to assess potential predictors of these outcomes.

Methods: For this multicentre prospective cohort study, patients awaiting corneal transplantation were recruited from 11 (academic) hospitals and eye clinics in the Netherlands. Participants (n = 238) completed the Centre for Epidemiological Studies Depression scale (CES-D), the Hospital Anxiety and Depression Scale-Anxiety subscale (HADS-A) and the Dutch ICF Activity Inventory Emotional Health subscale (DAI-EH) and Fatigue subscale (DAI-F) 1 month prior and 3, 6, 12 and 24 months after corneal transplantation. Sociodemographic and clinical characteristics, as well as coping styles as measured with the Utrecht Coping List, were considered as potential predictors for mental health outcomes (depression, anxiety, emotional health problems and fatigue). Linear mixed models were used to analyse and predict symptoms of depression, anxiety, emotional health problems and fatigue over time.

Results: Scores on the CES-D and HADS-A improved significantly from baseline to 24-months (mean scores CES-D: 8.6 vs. 7.7, p = 0.03; mean scores HADS-A: 3.7 vs. 3.2, p = 0.002). Scores on the DAI-EH and DAI-F also improved significantly from baseline to 24-months (mean scores DAI-EH: 10.7 vs. 7.5, p < 0.001; mean scores DAI-F: 17.4 vs. 11.3, p < 0.001). Male sex and Fuchs' dystrophy were important predictors of better mental health outcomes, whereas comorbidity, (dry) eye complaints and a passive reacting coping style were important predictors of worse mental health outcomes.

Conclusion: Corneal transplantation had a positive impact on mental health outcomes and important predictors were identified. This study may improve the understanding of patients and eyecare practitioners about the effects of corneal transplantation, leading to realistic communication about corneal transplantation expectations.

Purpose: The present study aimed to determine the potential impact of scleral lenses on intraocular pressure (IOP) by analysing the Bruch's membrane opening-minimum rim width (BMO-MRW) while the lenses are worn, in a population with keratoconus.

Methods: Participants were required to have keratoconus and be successfully fitted with scleral lenses for at least 3 months. A new pair of optimised scleral lenses was provided before the study. During the first session, corneal biomechanics was assessed using an air tonometer, coupling Scheimpflug technology. Then, a scan of the optic nerve was carried out using optical coherence tomography (OCT) at 2 h intervals for 6 h. Particular attention was paid to identifying the BMO-MRW, which represents the smallest distance between the BMO and the internal limiting membrane. These tests were repeated, respecting the time at which the initial measurements were taken, while the scleral lens was worn. Results from only one eye were analysed.

Results: A statistically significant change of 10.5 ± 3.6 μm (95% CI [241.3-473.1]; p = 0.02) in BMO-MRW was observed after 6 h of scleral lens wear, compared to measurements without lenses (4.8 ± 3.4 μm; 95% CI [285.1-439.7]; p = 0.18). The fluctuation was greater in participants with keratoconus than found in a previous study of regular corneas.

Conclusion: BMO-MRW became significantly thinner after 6 h of scleral lens wear compared with measurements without lenses. These variations may be associated with a rise in IOP during lens wear. Close monitoring for optic head changes should be carried out for patients at risk. These results should be compared with future longer-term studies including a larger cohort of patients.

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: This case-control study investigated whether defects in visual field contrast sensitivity are associated with exposure to occupational levels of pesticides in agricultural workers.

Methods: Twenty-seven individuals exposed to occupational levels of pesticides (exposed group) from 14 agricultural systems and 27 non-exposed individuals (non-exposed group) were measured using standard automated perimetry (30-2 full threshold). Visual sector analysis, targeting regions of the optic nerve head, was performed to examine for potential region-specific sensitivity differences. Participants also underwent comprehensive assessments, including general optometric examinations and demographic surveys. Symptoms and signs of neurotoxicity were assessed using the modified Q16 neurotoxic symptom questionnaire and biological testing for abnormal levels of Substance P in tears (an inflammatory marker associated with chemical exposure) and cholinesterase (which is inhibited by pesticides) in blood samples.

Results: Signs of chemical exposure were found as indicated by significantly higher levels of neurotoxic symptoms, higher concentrations of Substance P and lower levels of cholinesterase in the exposed group. Visual field global indices showed differences in contrast sensitivity between the exposed and non-exposed groups, with the exposed group demonstrating significantly lower means and larger pattern-standard deviations. Notably, visual field sector analysis revealed comparatively lower contrast sensitivity at nasal locations surrounding the optic nerve head in the exposed group.

Conclusion: This study found deficits in visual field contrast sensitivity to be associated with pesticide exposure, and selective loss at nasal locations centred on the optic nerve head may indicate retinal toxicity. These findings suggest the utility of visual field assessment as a potential method to evaluate pesticide-related health implications. The results highlight the need for ongoing monitoring and protective measures for agricultural workers exposed to pesticides to prevent potential visual and neurological damage.

Purpose: The aim of this study was to investigate changes in the light-adapted (LA) electroretinogram (ERG) associated with paediatric amblyopia.

Method: A total of 220 eyes from 81 postoperative paediatric cataract patients and 29 healthy children were enrolled in four groups, namely controls, unilaterally amblyopic eyes, non-amblyopic fellow eyes and bilaterally affected eyes. Differences in LA ERG variables (peak time and amplitude of a- and b-waves and photopic negative response [PhNR]) were compared across groups, as well as their associations with visual acuity and changes in axial length.

Results: The peak time of both the a-wave (p < 0.001) and b-wave (p < 0.001), as well as the amplitude of the b-wave (p < 0.001) and the PhNR (p = 0.04) differed significantly across groups. Compared to controls, affected eyes in both unilateral and bilateral groups showed significantly lower b-wave amplitude and longer a- and b-wave peak times (p < 0.008, Bonferroni-corrected). Additionally, fellow eyes in the unilateral group exhibited significantly longer b-wave peak times (p = 0.008). For all eyes, poorer visual acuity was associated with a longer peak time for both the a- (p = 0.006) and b-waves (p = 0.003), as well as lower amplitudes of the b-wave (p = 0.006) and PhNR (p = 0.02).

Conclusions: Changes in LA ERG components suggest alteration of retinal physiology in deprivation amblyopia. Thus, the LA ERG may provide additional information to help understand the mechanisms underlying deprivation amblyopia.