Search Results (33)

Background: Patients with primary angle-closure disease (PACD), those with no history of acute angle-closure glaucoma or laser iridotomy, rarely present with prominent corneal endothelial cell density (CECD) loss. To identify factors associated with decreased CECD in PACD, anterior segment parameters were compared in patients with PACD and normal CECD and patients with PACD and decreased CECD, using anterior segment optical coherence tomography (AS-OCT). Patients and Methods: Ten patients with PACD and CECD of less than 1500/mm² without a history of cataract surgery, acute angle-closure glaucoma, or prior laser glaucoma procedures were identified at the Kyorin Eye Center from January 2018 to July 2023. Patients with an obvious corneal guttata or apparent corneal edema were also excluded. Seventeen patients with PACD and normal CECD (normal CECD group) were used as the control. Simultaneous biometry of all anterior segment structures, including the cornea, anterior chamber, and iris, were assessed using a swept-source AS-OCT system. Results: Corneal curvature radius was significantly larger in the decreased CECD group compared with the corneal refractive power in the normal CECD group (p = 0.022, Mann–Whitney test). However, no significant differences were detected in other anterior segment morphology parameters. Multiple regression analysis with CECD as the dependent variable revealed that a large corneal curvature radius was a significant explanatory variable associated with corneal endothelial loss. Conclusions: Flattened corneal curvature may be a risk factor for corneal endothelial loss in patients with PACD. Full article

(1) Background: The early diagnosis of keratoconus is critical for prognosis. Traditional methods like ORA and Corvis ST measure overall corneal biomechanics but lack regional specificity and are affected by intraocular pressure. In contrast, Brillouin microscopy assesses regional corneal biomechanics without such limitations; (2) Methods: In total, 25 keratoconus patients and 28 healthy controls were included in this study. Corneal biomechanics were measured using the BOSS system (Brillouin Optical Scanning System) in a 10-point mode within an 8 mm diameter, and included the mean, maximum, minimum and standard Brillouin shift. The Corvis ST parameters extracted included the CBI (Corneal Biomechanical Index), CCBI (Corvis Biomechanical Index for Chinese populations), SSI (Stress–Strain Index), DA (Deformation Amplitude), IIR (Inverse Integrated Radius), and SP-A1 (Stiffness Parameter at First Applanation); (3) Results: BOSS showed significant differences in the inferior nasal region (p = 0.004) and central region (p = 0.029) between groups, but not in peripheral regions (p = 0.781). In a comparison of the Brillouin frequency shifts measured between groups, there was no difference in the Mean (p = 0.452) and Max (p = 0.487), but the Min (p = 0.003), Standard (p = 0.000), and Max–Min (p = 0.006) all showed differences. Corvis ST identified significant differences in six parameters (CBI, CCBI, SSI, DA, IIR, and SP-A1) between groups (p < 0.001). Correlations were found between the BOSS and Corvis ST results, with moderate correlations in the inferior nasal region; (4) Conclusions: The BOSS Brillouin microscope can provide an accurate diagnostic evaluation for the corneal biomechanical differences between normal eyes and keratoconus, independent of IOP (Intraocular Pressure) and CCT (Central Corneal Thickness), with a good correlation with Corvis ST, especially in assessing regional biomechanics. Full article

The impact of prematurity has been reported to affect ocular development during infancy and childhood. Research into long-term ocular outcomes in adults born preterm is highly relevant due to a possible impact on the development of age-related ocular diseases such as macular degeneration. The aim was to review the currently available literature regarding outcomes of prematurity on ocular morphology in adults to provide a summary of the long-term effects of prematurity and associated factors such as low birth weight (BW) and retinopathy of prematurity (ROP) and its treatment. Adults formerly born preterm have a higher prevalence of refractive error, lower visual acuity, a higher prevalence of strabismus, shorter axial length, a steeper corneal radius, increased macular thickness, and a thinner peripapillary retinal nerve fiber layer thickness (RNFL), as well as changes in vessel anatomy and the foveal avascular zone. Adults who suffered from ROP have a high risk of myopic refractive error, amblyopia, shallower anterior chambers and thicker crystalline lenses, higher corneal aberrations, thinner RNFL thickness, and foveal hypoplasia. Individuals with advanced ROP requiring treatment also have higher rates of astigmatism, an increased temporal RNFL thickness, altered macular curvature, and reduced visual acuity. Prematurity leads to lifelong ocular morphological and functional changes, suggesting that fetal origins may contribute to age-related ocular diseases. This could have implications for ophthalmologic monitoring and the frequency of check-ups in adulthood. Full article

Background and Objectives: Scleral lenses are widely used for visual rehabilitation in keratoconus patients, but their long-term effects on corneal tomography remain unclear. This study aims to evaluate the impact of 12-month scleral lens wear on corneal tomography in keratoconus patients through a case-controlled design. Materials and Methods: This retrospective study included 220 keratoconus patients, of whom 10 eyes were treated with SoClear (Brighten Optix Corporation, Taipei, Taiwan) mini-scleral lenses for over one year (SL group). A control group of 14 eyes was matched using Mahalanobis distance matching based on anterior maximum keratometry (K_max) and age. Both groups were evaluated at baseline and 12 months. Corneal tomography was assessed using the Pentacam HR (Oculus, Wetzlar, Germany), analyzing parameters such as anterior and posterior corneal curvature, thinnest corneal thickness (TCT), and higher-order aberrations. Generalized estimating equations (GEEs) were employed to assess the time-by-treatment effect between the two groups. Results: The SL group included 10 eyes from eight patients (seven males, one female; mean age 30.40 ± 6.52 years), while the control group included 14 eyes from 11 patients (three males, wight females; mean age 27.43 ± 8.11 years). Best corrected visual acuity with spectacles improved significantly with scleral lenses (p = 0.011) and remained stable (p = 0.044) at 12 months. Significant interaction effects were found in Ambrósio relational thickness (p = 0.006), posterior radius curvature (p = 0.047), posterior mean keratometry (p = 0.019), posterior flat keratometry (p = 0.023), and thinnest corneal thickness angle (p = 0.023); the SL group demonstrated less progression in these parameters compared to the control group. Conclusions: This case-controlled study highlights the 12-month impact of scleral lenses on keratoconus, showing improved visual acuity compared to spectacles, stabilized posterior corneal curvature, and maintained corneal thickness. Further prospective studies with larger cohorts are needed to assess scleral lens effect on keratoconus progression. Full article

Background/Objectives: The prevalence of myopia is increasing globally, including in Spain. The early detection of ocular biometric parameters associated with myopia development is crucial for implementing control strategies. This study aims to describe the normative biometric values in a Spanish school-aged population and compare them with previously established reference data. Methods: A cross-sectional, observational, and analytical study was conducted on 558 students aged 6 to 12 years from the Educare Valdefuentes School in Madrid. Ocular biometric parameters, including axial length (AL), corneal curvature (CR), anterior chamber depth (ACD), crystalline lens thickness (LT), corneal thickness (CCT), and posterior vitreous depth (PVD), were measured using IOLMaster 700. The axial length/corneal radius (AL/CR) ratio was calculated. Percentile growth curves were generated, and the results were statistically analyzed using IBM SPSS 29. Results: AL significantly increased with age (p < 0.001), and boys had longer AL than girls. The AL/CR ratio showed a moderate correlation with myopia risk (ρ = 0.647, p < 0.001). Compared to previous European studies, no significant differences were found, except for minor variations in AL and CR. Conclusions: These percentile-based biometric values provide a useful reference for monitoring ocular growth and assessing myopia risk in Spanish children. The AL/CR ratio remains a strong predictor of myopia development, supporting its role in early detection strategies. Full article

Background/Objectives: The evaluation of the differences in corneal epithelial thickness profiles in healthy eyes and eyes with mild and moderate stages of keratoconus, using optical coherence tomography (OCT). Methods: Fifty-two healthy eyes (group 0), forty-one eyes with mild keratoconus (group I), and thirty eyes with moderate keratoconus (group II) were included in this study. Only one of the patient’s eyes was enrolled, and they were divided into groups using the Amsler–Krumeich (A–K) classification—stage I and II. All patients underwent a visual acuity assessment, slit-lamp examination, corneal tomography, and automatic mapping of corneal thickness and epithelial thickness on a diameter of 9 mm. Corneal tomography with a Placido/Scheimpflug instrument (Sirius, CSO, Florence, Italy) and OCT with a corneal adaptor module (Avanti RTVue XR, Optovue, Lombard, IL, USA) were used. Results: Minimum corneal epithelium thickness was 49.5, 43, and 40 µm in groups 0, I, and II, respectively (Kruskal–Wallis test, p < 0.001). A moderate correlation was found between minimum epithelial thickness and the apex curvature (Pearsons’s coefficient r = −0.62, p < 0.001) and posterior radius of central corneal curvature (Pearsons’s coefficient r = 0.62, p < 0.001). The difference between minimum and maximum epithelial thickness showed a high correlation (r = −0.770, p < 0.001). In groups I and II, on corneal epithelial thickness maps the thinnest sector, located inferiorly and temporally to the center, was surrounded by sectors with increased thickness. Conclusions: At the apex of the cone, the corneal epithelium becomes thinner, and a thicker ring forms around the cone. Although there is a moderate-to-strong correlation to parameters linked with the severity of keratoconus, and minimum epithelial thickness as well as the minimum–maximum difference, it is not possible to establish cut-off values for stages I and II in the Amsler–Krumeich (A–K) classification. Full article

Objective: To analyse variations in axial length (AL), corneal radius (CR) and the AL/CR ratio over one year in eight-year-old schoolchildren, considering sex, ethnicity and refractive error. Methods: Vision screenings were conducted in 16 schools in Terrassa (Barcelona, Spain) with eight-year-old children as part of the CISViT project. Measurements included ocular biometrics (AL and CR) and non-cycloplegic autorefraction for refractive error. Parental questionnaires provided demographic data (birth date, ethnicity). The same procedures were repeated after one year. Results: Ocular biometric parameters differed by sex and ethnicity. Boys and children of Maghreb descent had longer AL and flatter CR than girls and Caucasian children (p < 0.001 for both visits). The AL/CR ratio was higher in boys than girls (p = 0.002 in the initial visit and p = 0.011 in the follow-up visit) but consistent across ethnicities (p = 0.291 and p = 0.390). AL and AL/CR ratio differed significantly by refractive error status (p < 0.001 in both visits), increasing in more myopic children, while CR showed no significant difference. In myopic children, the AL/CR ratio exceeded 3.0, and typical sex-based biometric differences diminished. Growth rates for AL and AL/CR ratio were similar across sex and ethnicity, indicating minimal demographic influence. Conclusions: AL and CR differ significantly by sex and ethnicity, with demographic differences evident in baseline measurements but not in growth rates over one year. The consistency of the AL/CR ratio across ethnicities, despite sex-based differences, supports its utility as a reliable metric for assessing refractive development in diverse populations. Full article

Gaze tracking and estimation are essential for understanding human behavior and enhancing human–computer interactions. This study introduces an innovative, cost-effective solution for real-time gaze tracking using a standard webcam, providing a practical alternative to conventional methods that rely on expensive infrared (IR) cameras. Traditional approaches, such as Pupil Center Corneal Reflection (PCCR), require IR cameras to capture corneal reflections and iris glints, demanding high-resolution images and controlled environments. In contrast, the proposed method utilizes a convolutional neural network (CNN) trained on webcam-captured images to achieve precise gaze estimation. The developed deep learning model achieves a mean squared error (MSE) of 0.0112 and an accuracy of 90.98% through a novel trajectory-based accuracy evaluation system. This system involves an animation of a ball moving across the screen, with the user’s gaze following the ball’s motion. Accuracy is determined by calculating the proportion of gaze points falling within a predefined threshold based on the ball’s radius, ensuring a comprehensive evaluation of the system’s performance across all screen regions. Data collection is both simplified and effective, capturing images of the user’s right eye while they focus on the screen. Additionally, the system includes advanced gaze analysis tools, such as heat maps, gaze fixation tracking, and blink rate monitoring, which are all integrated into an intuitive user interface. The robustness of this approach is further enhanced by incorporating Google’s Mediapipe model for facial landmark detection, improving accuracy and reliability. The evaluation results demonstrate that the proposed method delivers high-accuracy gaze prediction without the need for expensive equipment, making it a practical and accessible solution for diverse applications in human–computer interactions and behavioral research. Full article

Purpose: This study aimed to employ the incremental digital image correlation (DIC) method to obtain displacement and strain field data of the cornea from Corvis ST (CVS) sequences and access the performance of embedding these biomechanical data with machine learning models to distinguish forme fruste keratoconus (FFKC) from normal corneas. Methods: 100 subjects were categorized into normal (N = 50) and FFKC (N = 50) groups. Image sequences depicting the horizontal cross-section of the human cornea under air puff were captured using the Corvis ST tonometer. The high-speed evolution of full-field corneal displacement, strain, velocity, and strain rate was reconstructed utilizing the incremental DIC approach. Maximum (max-) and average (ave-) values of full-field displacement V, shear strain γxy, velocity VR, and shear strain rate γxyR were determined over time, generating eight evolution curves denoting max-V, max-γxy, max-VR, max-γxyR, ave-V, ave-γxy, ave-VR, and ave-γxyR, respectively. These evolution data were inputted into two machine learning (ML) models, specifically Naïve Bayes (NB) and Random Forest (RF) models, which were subsequently employed to construct a voting classifier. The performance of the models in diagnosing FFKC from normal corneas was compared to existing CVS parameters. Results: The Normal group and the FFKC group each included 50 eyes. The FFKC group did not differ from healthy controls for age (p = 0.26) and gender (p = 0.36) at baseline, but they had significantly lower bIOP (p < 0.001) and thinner central cornea thickness (CCT) (p < 0.001). The results demonstrated that the proposed voting ensemble model yielded the highest performance with an AUC of 1.00, followed by the RF model with an AUC of 0.99. Radius and A2 Time emerged as the best-performing CVS parameters with AUC values of 0.948 and 0.938, respectively. Nonetheless, no existing Corvis ST parameters outperformed the ML models. A progressive enhancement in performance of the ML models was observed with incremental time points during the corneal deformation. Conclusion: This study represents the first instance where displacement and strain data following incremental DIC analysis of Corvis ST images were integrated with machine learning models to effectively differentiate FFKC corneas from normal ones, achieving superior accuracy compared to existing CVS parameters. Considering biomechanical responses of the inner cornea and their temporal pattern changes may significantly improve the early detection of keratoconus. Full article

(1) Background: Our previous data indicated that disturbance of the Transforming Growth Factor beta (TGFB) signaling pathway via its Type-2 Receptor (TGFBR2) can cause a Corneal Ectasia (CE)-like phenotype. The purpose of this study is to elucidate whether the SMAD4-dependent signaling pathway is involved in the TGFBR2-related CE-like pathogenesis. (2) Methods: Smad4 was designed to be conditionally knocked out from keratocytes. Novel triple transgenic mice, Kera^rtTA; Tet-O-Cre; Smad4^flox/flox (Smad4^kera-cko), were administered with doxycycline (Dox). Optical Coherence Tomography (OCT) was performed to examine Central Corneal Thickness (CCT), Corneal Radius, Anterior Chamber and CE-like phenotype and compared to the littermate Control group (Smad4^Ctrl). (3) Results: The OCT revealed normal cornea in the Smad4^Ctrl and a CE-like phenotype in the Smad4^kera-cko cornea, in which the overall CCT in Smad4^kera-cko was thinner than that of Smad4^Ctrl at P42 (n = 6, p < 0.0001) and showed no significant difference when compared to that in Tgfbr2^kera-cko. Furthermore, the measurements of the Anterior Chamber and Corneal Radius indicated a substantial ectatic cornea in the Smad4^kera-cko compared to Smad4^Ctrl. The H&E staining of Smad4^kera-cko mimics the finding in the Tgfbr2^kera-cko. The positive immunostaining of cornea-specific marker K12 indicating the cell fate of cornea epithelium remained unchanged in Smad4^kera-cko and the Proliferating Cell Nuclear Antigen (PCNA) immunostaining further indicated an enhanced proliferation in the Smad4^kera-cko. Both immunostainings recapitulated the finding in Tgfbr2^kera-cko. The Masson’s Trichrome staining revealed decreased collagen formation in the corneal stroma from both Smad4^kera-cko and Tgfbr2^kera-cko. The collagen type 1 (Col1a1) immunostaining further confirmed the reduction in collagen type 1 formation in Smad4^kera-cko. (4) Conclusions: The aforementioned phenotypes in the Smad4^kera-cko strain indicated that the SMAD4-dependent signaling pathway is involved in the pathogenesis of the CE-like phenotype observed in Tgfbr2^kera-cko. Full article

Purpose: To evaluate changes in the ocular surface microbiome (OSM) between pre- and post-haemopoietic stem cell transplant (HSCT) in the same patient, and to assess the potential impact of these changes in ocular graft-versus-host disease (o)GVHD development. Methods: Lower fornix conjunctival swabs of 24 patients were obtained before and after HSCT and subjected to DNA extraction for amplification and sequencing of the V3-V4 regions of the bacterial 16S rRNA gene. The obtained reads were reconstructed, filtered, and clustered into zero-radius operational taxonomic units (zOTUs) at 97% identity level before taxonomic assignment, and biodiversity indexes were calculated. Transplant characteristics were recorded, and dry eye was diagnosed and staged 1–4 according to the Dry Eye WorkShop (DEWS) score. Results: No significant difference in OSM alpha diversity between pre- and post-transplant was found. A significant difference in beta diversity was observed between patients with a DEWS score of 1 versus 3 (p = 0.035). Increased corneal damage between pre- and post-HSCT was significantly associated with a decrease in alpha diversity. The changes in OSM were not associated with oGVHD, nor with any transplant parameter. Conclusions: This preliminary study is the first study to analyse changes in the OSM before and after HSCT longitudinally. No trend in OSM biodiversity, microbial profile, or overall composition changes before and after HSCT was significant or associated with oGVHD onset. The great variability in the observed OSM profiles seems to suggest the absence of a patient-specific OSM “signature”. Full article

In this study, the severity of eye pain (EP) and associated objective findings were evaluated in aqueous-deficient dry eye (ADDE) patients using PainVision^®, a quantitative pain-measuring device. This study involved 53 eyes of 53 ADDE patients (6 males and 47 females; mean age: 64.4 ± 13.4 [mean ± SD] years). Of those, 18 eyes of 18 patients underwent punctal occlusion, and EP and objective findings in those patients were evaluated before and after treatment. In all patients, the severity of EP as measured by PainVision^® was assessed using the Pain Degree (PD). The median PD for the 53 patients was 30.6 µA/µA (interquartile range, 16.9–93.2), and the nasal and central corneal staining score and the upper lid-wiper epitheliopathy score were significantly correlated with PD (R = 0.33, 0.33, and 0.28, respectively) (all: p < 0.05). Using the least squares method, the central corneal staining score most significantly affected PD. In the 18 cases that underwent punctal occlusion, PD was significantly reduced (median PD: 24.8 to 7.1 µA/µA; p < 0.0001). Using the least squares method, the central corneal staining score and tear meniscus radius were significantly more influential as factors contributing to PD before and after treatment, and central corneal epithelial damage was the factor most associated with ADDE-related EP. Full article

Punctal occlusion (PO) is considered to improve both tear-film instability and increased friction during blinking and may consequently affect blinks. The purpose of this study was to investigate the effect of PO on blinks. This study involved 16 eyes of 16 severe aqueous deficient dry eye (ADDE) patients (mean age: 65.7 years). In all eyes, tear meniscus radius (TMR), spread grade (SG) of the tear-film lipid layer (i.e., SG 1-5: 1 being the best), fluorescein break-up time (FBUT), corneal epithelial damage score (CED), conjunctival epithelial damage score, corneal filament (CF) grade, lid-wiper epitheliopathy (LWE) grade, and superior limbic keratoconjunctivitis (SLK) grade were evaluated at before and at more than 1-month after PO. Moreover, using a custom-made high-speed blink analyzer, palpebral aperture height, blink rate, upper-eyelid closing-phase amplitude/duration/maximum velocity, and upper-eyelid opening-phase amplitude/duration/maximum velocity were measured at the same time point. After PO, TMR, SG, FBUT, CED, and the CF, LWE, and SLK grades were significantly improved, and upper-eyelid opening/closing-phase amplitude and maximum velocity significantly increased (all p < 0.04). The findings of this study suggest that PO improves ocular surface lubrication and that blink-related parameters can reflect the friction that occurs during blinking in eyes with severe ADDE. Full article

The aim of this study was to evaluate the biomechanical changes in the cornea after wearing soft contact lenses (CLs) in healthy myopic patients measured with a Corvis ST^® (CST, Oculus Optikgeräte GmbH, Wetzlar, Germany) analyser. This prospective, cross-sectional, single-centre study was performed on twenty-two Caucasian patients aged between 19 and 24 years (20.64 ± 1.21 years) range. Five device-specific biomechanical parameters, the central corneal thickness (CCT), and biomechanically corrected intraocular pressure (bIOP) were measured prior to fitting and one month after CL wear. Differences between the means of the deflection amplitude ratio (DA Ratio) and the standard deviation of the DA Ratio (SD DA Ratio) pre- and post-CL wear were found to be significant (p value = 0.002 in both cases). Significant differences were found between pre- and post-CL wear values in CCT (p value = 0.013). For all other biomechanical measures, no significant differences were observed before and after treatment. A significant association was found between changes in bIOP and classification according to changes in Int. Radius (p value = 0.047) and SSI (p value = 0.026) standard deviations. The corneal biomechanical indices provided by CST demonstrate that the fitting of soft CLs is a safe optical compensation method for the stability of corneal stiffness. No significant differences were found pre- and post-CL wear in the assessment of bIOP. Full article

The aim of this work was to compare an enhanced monofocal (RayOne EMV RAO200E, Rayner) and standard monofocal (RayOne RAO600C Aspheric, Rayner) intraocular lenses (IOLs) for three nominal powers (+10.00 D, +20.00 D and +30.00 D) as a function of the optical aperture diameter (pupil diameter) using a commercial Schlieren phase-shifting deflectometer NIMO TR1504 (Lambda-X, Belgium). From the wavefront maps measured by this instrument, the radial power profiles, the spherical aberration coefficients of the Zernike polynomial expansion (as a function of the optical aperture radius), and the root-mean-square (RMS) of the high-order aberrations (HOAs) were obtained and analyzed by comparing the two models. The results showed that the effective added power that could be obtained with the enhanced model depended directly on the pupil size and the power of the IOL implanted. The higher additions were achieved with the higher nominal IOL powers. The relationship between the pupil diameter, the corneal aberration of the patients and the power profile of these IOLs could have a crucial implication on the far distance and the final effective addition. However, it is important to note that these findings should be clinically validated through the implantation of these models in patients’ lenses. Full article