Translational Vision Science & Technology最新文献

Purpose: We present RetOCTNet, a deep learning tool to segment the retinal nerve fiber layer (RNFL) and total retinal thickness automatically from optical coherence tomography (OCT) scans in rats following retinal ganglion cell (RGC) injury.

Methods: We created unilateral RGC injury by ocular hypertension (OHT) or optic nerve crush (ONC), and contralateral eyes were not injured. We manually segmented the RNFL and total retina of 3.0-mm radial OCT scans (1000 A-scans per B-scan, 20 frames per B-scan) as ground truth (n = 192 scans). We used these segmentations for training (80%), testing (10%), and validation (10%) to optimize the F1 score. To determine the generalizability of RetOCTNet, we tested it on volumetric scans of a separate cohort at baseline and 4, 8, and 12 weeks post-ONC.

Results: RetOCTNet's segmentations achieved high F1 scores relative to the ground-truth segmentations created by human annotators: 0.88 (RNFL) and 0.98 (retinal thickness) for control eyes, 0.84 and 0.98 for OHT eyes, and 0.78 and 0.96 for ONC eyes, respectively. On volumetric scans 12 weeks post-ONC, RetOCTNet calculated thinning of 29.49% and 10.82% in the RNFL and retina at the optic nerve head (ONH) and thinning of 38.34% and 9.85% in the RNFL and retina superior to the ONH.

Conclusions: RetOCTNet can segment the RNFL and total retinal thickness of both radial and volume OCT scans. RetOCTNet can be applied to longitudinally monitor RNFL in rodent models of RGC injury.

Translational relevance: This tool automates RNFL and retinal thickness measurement for rat OCT scans following RGC injury, reducing analysis time and increasing the consistency between studies.

Purpose: The purpose of this study was to develop an artificial intelligence (AI)-based intraocular lens (IOLs) power calculation formula for improving the accuracy of IOLs power calculations in patients with congenital ectopia lentis (CEL).

Methods: A total of 651 eyes with CEL that underwent IOLs implantation surgery were included in this study. An AI-based ensemble formula-the Jiang Formula, was developed using a training dataset of 520 eyes and evaluated on a testing dataset of 131 eyes. A five-fold cross-validation and a two-layer ensemble learning model were constructed. The formula was then tested in a test set and compared against five current classic formulas.

Results: The cohort included young patients (mean age = 14.38 ± 13.35 years). The Jiang Formula showed the lowest prediction error (PE; = 0.08 ± 1.01 diopters [D]), absolute error (AE; = 0.77 ± 0.65 D), median absolute error (MedAE; = 0.66 D), and root mean square error (RMSE; = 1.02 D) among six formulas (P < 0.001). Moreover, 68.00% of the eyes in the test set had AE within 1.0 D in the Jiang Formula.

Conclusions: AI-integrated two-layer ensemble learning model demonstrates promising applications in IOLs power calculations for patients with CEL, not only providing higher predictive accuracy than current classic formulas but also accommodating extreme values and variations in surgical techniques.

Translational relevance: The Jiang Formula, an AI-integrated two-layer ensemble learning model, enhances IOLs power calculation accuracy in patients with CEL, ultimately improving surgical outcomes and supporting more effective, personalized treatment in this unique patient group.

Purpose: The retinal pigment epithelium (RPE) is crucial for photoreceptor function, and its dysfunction is associated with several retinal degenerative diseases. This study examines how different sugars in preservation media affect the viability of RPE cells, highlighting the need for effective storage solutions for cell transplantation.

Methods: Human RPE cells were cultured and suspended in modified media with various sugars. The survival rate was measured for cells cultured under adhesion for 3 weeks and for those stored at 37°C for 24 hours. Metabolism was evaluated using liquid chromatography, whereas the responses to hypoxia were assessed with specific markers.

Results: Fructose-containing media significantly enhanced RPE cell survival, even under hypoxic conditions. In adherent cultures, fructose showed higher survival rates compared to galactose, which had a notably low survival rate. Chromatography results indicated that fructose played a role in non-anaerobic metabolism, helping to explain its effectiveness. In suspension, fructose maintained higher cell viability than glucose and suppressed hypoxia markers, suggesting increased resistance to hypoxic stress.

Conclusions: The study highlights the critical role of sugar composition in preservation media on RPE cell survival, positioning fructose as a potential enhancer. Its antioxidative properties suggest fructose could be effective in suspension preservation. These findings indicate that fructose-containing media are promising for preserving RPE cells and could have broader applications in preserving various cell types and tissues.

Translational relevance: The results of this study may allow for longer-term storage of RPE cells, potentially increasing the versatility of cell transplantation therapy.

Purpose: To elucidate the relationship between diabetic retinopathy (DR) and frailty and investigate genetic correlations and causality.

Methods: We analyzed data from the US National Health and Nutrition Examination Survey, which included 1003 individuals with diabetes. DR was evaluated via nonmydriatic retinal imaging, and frailty was measured using a 49-item frailty index. The association between DR and frailty was assessed using survey-weighted logistics regression adjusted for multiple covariates, including age, sex, race, education level, family income-to-poverty ratio, marital status, and Healthy Eating Index. Genetic correlations and causal relationships were investigated through linkage disequilibrium score regression and bidirectional Mendelian randomization.

Results: DR was significantly associated with higher odds of frailty after full adjustment (odd ratio [OR] = 4.25; 95% confidence interval [CI], 1.08-16.67; P = 0.040). The association was robust and did not significantly differ across age (P interaction = 0.080), sex (P interaction = 0.216), or race (P interaction = 0.749) groups. DR exhibited a moderate but significant genetic correlation with frailty (rg = 0.27, standard error = 0.04; P = 2.43 × 10-10). Genetically inferred DR was significantly associated with a greater frailty index (β = 0.03; 95% CI, 0.01-0.05; P < 0.001), whereas frailty was not associated with DR risk (OR = 1.20; 95% CI, 0.80-1.81; P = 0.376).

Conclusions: Our findings suggest that DR is associated with an increased risk of frailty, indicating that DR not only impairs vision but also accelerates physical decline.

Translational relevance: This study highlights the critical need for integrated care approaches that incorporate frailty screening and proactive management in individuals with DR to prevent further health deterioration and improve both quality of life and long-term outcomes.

Purpose: Continuous visual stimulus tracking could be used as an easy alternative to standard automated perimetry (SAP) for visual function screening. With continuous visual stimulus tracking, we simplified the perimetric task to following a moving dot on a screen with the eyes. Here, we determined whether tracking performance (the agreement between gaze and stimulus position) enables the detection and quantification of glaucomatous visual function loss (in terms of SAP), and whether it shows a learning effect.

Methods: We evaluated the tracking performance of 36 cases with early, moderate, or severe glaucoma (median with interquartile range [IQR] age = 70 [67-74] years) and 36 controls (median = 70, IQR = 67-72 years). All participants monocularly tracked a moving stimulus (Goldmann size III) at 3 Weber contrast levels: 40, 160, and 640%, while their eye movements were recorded.

Results: Glaucoma decreased the tracking performance, with the most severe reduction in the severe glaucoma cases. A distinction between groups was possible, but depended on the contrast level: tracking performance of early glaucoma cases was significantly different from controls only at 40% contrast. Within the cases, glaucomatous visual function loss (SAP Mean Sensitivity [MS]) was best correlated with tracking performance when using 160% contrast. There was no significant learning effect.

Conclusions: Overall, the data indicate that it is possible to detect and quantify glaucomatous visual function loss with continuous visual stimulus tracking.

Translational relevance: Continuous visual stimulus tracking is an easy, fast, and intuitive technique that has the potential for diagnostic applications in detection of new glaucoma cases and monitoring of previously diagnosed cases.

Purpose: A human model able to simulate the manifestation of corneal endothelium decompensation could be advantageous for wound healing and future cell therapy assessment. The study aimed to establish an ex vivo human cornea endothelium wound model where endothelium function can be evaluated by measuring corneal thickness changes.

Methods: The human cornea was maintained in an artificial anterior chamber, with a continuous culture medium infusion system designed to sustain corneal endothelium and epithelium simultaneously. The corneal thickness was used to assess corneal endothelial cell function. Immunostaining was used to evaluate cell viability and endothelial cell marker expression, ZO-1 and Na/K ATPase.

Results: Human corneas with intact corneal endothelium were maintained in the ex vivo model for 28 days, showing normal corneal thickness with a clear and transparent appearance. Corneal endothelial cells were alive and expressed ZO-1 and Na/K ATPase at the end of the organ culture. The endothelium wounded corneas showed persistent corneal edema with an increase in corneal thickness at 654.6 ± 31.7 µm. Staining results showed that no cells migrated to cover the wound and no expression of ZO-1 and Na/K ATPase on the posterior surface of the cornea was found.

Conclusions: This study provided a novel method to establish an ex vivo human cornea organ culture model, where corneal endothelium function can be evaluated by accessing the corneal thickness.

Translational relevance: The ex vivo model established in this study can provide an alternative to the animal model in studying corneal endothelium decompensation.

Purpose: To characterize frequency-dependent wave speed dispersion in the human cornea using microliter air-pulse optical coherence elastography (OCE), and to evaluate the applicability of Lamb wave theory for determining corneal elastic modulus using high-frequency symmetric (S0) and anti-symmetric (A0) guided waves in cornea.

Methods: Wave speed dispersion analysis for transient (0.5 ms) microliter air-pulse stimulation was performed in four rabbit eyes ex vivo and compared to air-coupled ultrasound excitation. The effects of stimulation angle and sample geometry on the dispersion were evaluated in corneal phantoms. Corneal wave speed dispersion was measured in 36 healthy human eyes in vivo.

Results: Air-pulse-induced dispersion was comparable to ultrasound-induced dispersion between 0.7 and 5 kHz (mean-difference ± 1.96 × SD: 0.006 ± 0.5 m/s) in ex vivo rabbit corneas. Stimulation 0° relative to the surface normal generated A0 Lamb waves in corneal tissue phantoms, while oblique stimulation (35° and 65°) generated S0 waves. Stimulating normal to the human corneal apex in vivo (0°) induced A0 waves, plateauing at 10.87 to 13.63 m/s at 4 kHz, and when obliquely stimulated at the periphery (65°), produced S0 waves, plateauing at 13.10 to 15.98 m/s at 4 kHz.

Conclusions: Air-pulse OCE can be used to measure human corneal Lamb wave dispersion of A0 and S0 propagation modes in vivo. These modes are selectively excited by changing the stimulation angle. Accounting for wave speed dispersion enables reliable estimation of corneal elastic modulus in vivo.

Translational relevance: This work demonstrates the feasibility of air-pulse stimulation for robust OCE measurements of corneal stiffness in vivo for disease detection and therapy evaluation.

Purpose: The purpose of this study was to evaluate the correlation between axial length (AL) and retinal oxygen dynamic parameters in adult patients.

Methods: This was an observational cross-sectional study with 79 Chinese adults with myopia aged 18 to 37 years. All participants underwent AL measurements, cycloplegic refraction, and other ophthalmic examinations. Additionally, the retinal oxygen kinetics imaging and analysis (ROKIA) system was utilized to obtain the retinal oxygen dynamic parameters of all patients. Simple and multiple linear regression tests were used to assess the correlation between various oxygen dynamic parameters and AL.

Results: The mean age, AL, and spherical equivalent (SE) of subjects were 26.32 ± 5.4 years, 25.78 ± 1.06 mm, and -5.13 ± 2.1 diopters (D), respectively. The Pearson correlation coefficients among AL and retinal oxygen delivery (DO2) and retinal oxygen metabolism (MO2) were -0.44 (95% confidence interval = -0.24 to -0.60, P < 0.001), -0.26 (95% confidence interval = -0.04 to -0.46, P = 0.02), respectively. The group with high myopia exhibited lower DO2 and higher oxygen extraction fraction (OEF) compared with the group with moderate myopia, and no significant difference was observed in MO2 between the two groups. In multivariate analyses adjusting for age, sex, intraocular pressure (IOP), and anterior chamber depth (ACD), a longer AL was significantly associated with decreased DO2 (standardized regression coefficient B = -0.47, P < 0.001).

Conclusions: Retinal oxygen dynamic parameters, including DO2 and MO2, were decreased with longer AL in myopic eyes. Patients with high myopia demonstrated an elevated OEF than those with moderate myopia.

Translational relevance: This study demonstrated that the retinal oxygen metabolism changes in myopia, as confirmed using a novel device that quantifies retinal oxygen dynamic parameters and provides a new monitoring approach for other hypoxic retinal diseases.

The introduction of optical coherence tomography (OCT) in the 1990s revolutionized diagnostic ophthalmic imaging. Initially, OCT's role was primarily in the adult ambulatory ophthalmic clinics. Subsequent advances in handheld form factors, integration into surgical microscopes, and robotic assistance have expanded OCT's utility and impact outside of its initial environment in the adult outpatient ophthalmic clinic. In this review, we cover the use of OCT in the neonatal intensive care unit (NICU) environment with a handheld OCT, recent developments in intraoperative OCT for data visualization and measurements, and recent work and demonstration of robotically aligned OCT systems outside of eye clinics. Of note, advances in these areas are a legacy of our colleague, the late Joseph Izatt. OCT has been an important innovation for ocular diagnostics, and these advances have helped it continue to extend in new directions.

Purpose: Although the lens undoubtedly plays a major role in presbyopia, altered lens function could be in part secondary to age-related changes of the ciliary muscle. Ciliary muscle changes with accommodation have been quantified using optical coherence tomography, but so far these studies have been limited to quantifying changes in ciliary muscle thickness, mostly at static accommodative states. Quantifying ciliary muscle thickness changes does not effectively capture the dynamic anterior-centripetal movement of the ciliary muscle during accommodation. To address this issue, we present a method to quantify the movement of the ciliary muscle during accommodation using trans-scleral optical coherence tomography images obtained dynamically.

Methods: An image processing framework including distortion correction, geometric transformation, and Procrustes analysis, was used to quantify the anterior-centripetal movement of the ciliary muscle apex and centroid during accommodation. The method was applied in a preliminary study to quantify ciliary muscle displacement and its relation to lens thickness change with accommodation on two young adults and two prepresbyopes.

Results: The magnitude and the direction relative to the pupil plane of the apex/centroid displacement in response to a two diopters (2D) stimulus were 0.16/0.20 mm at 11.3°/30.5° and 0.26/0.34 mm at 6.6°/33.2° for the young adults and 0.20/0.20 mm at 29.7°/40.6° and 0.24/0.40 mm at 33.0°/31.7° for the prepresbyopes, respectively.

Conclusions: This study demonstrates the feasibility of quantifying dynamic anterior-centripetal movement of the ciliary muscle during accommodation using optical coherence tomography. The method better captures the functional response of the muscle than the quantification of thickness changes.

Translational relevance: We provide a method that holds potential to better understand the age-related changes of the ciliary muscle on presbyopia.