Profiles, Distribution, and Functions of Gamma Delta T Cells in Ocular Surface Homeostasis and Diseases.

The ocular surface microenvironment, containing the cornea, conjunctiva, and lacrimal gland, constitutes the mucosal frontline of the eye and houses a myriad of immune cells. As a part of unconventional T cells, gamma delta (γδ) T cells differ in the development and functions from canonical alpha beta (αß) T cells. They are predominantly situated in mucosal sites throughout the body, including ocular surface tissues. Recent research has elucidated that γδ T cells serve as the primary interleukin-17A (IL-17A) source in the conjunctiva. They play a pivotal role in preserving ocular surface homeostasis and exhibit both protective and pathogenic roles in ocular surface diseases. This review delves into the general profiles of γδ T cells, their distribution in ocular surface tissues, and consolidates current insights into their functions in different conditions including dry eye disease, infectious keratitis, corneal wound healing, anterior chamber-associated immune deviation, allergic conjunctival disease, and diabetic ocular surface disease. The aim is to provide a systemic perspective on γδ T cells in the ocular surface microenvironment and outline potential directions for future studies.

Prevalence data for total corneal astigmatism in cataract patients.

PURPOSE: To report the prevalence data for total corneal astigmatism (TCA) in cataract patients. METHODS: The authors retrospectively collected and analyzed the preoperative biometric data of the patients who underwent cataract surgery in the Department of Ophthalmology, Peking University Third Hospital, from January 2019 to May 2023. RESULTS: The mean age of the 10817 patients was 71 ± 10 years; the male/female ratio was 4653/6164. The mean TCA obtained by the IOLMaster 700 (Carl Zeiss Meditec AG, Jena, Germany), the Abulafia-Koch (AK) formula, and the Barrett toric calculator was 1.11 ± 0.81 diopter (D), 1.13 ± 0.75 D, and 1.12 ± 0.74 D respectively, which was significantly greater than the mean standard keratometric (K) astigmatism (0.99 ± 0.75 D) obtained by IOLMaster 700. Against-the-rule (ATR) astigmatism was dominant in all the TCA measurements, and its proportion increased with age. TCA measurements by different methods exhibit high variability, with a total of 1574 (8.9%) data sets from 1016 (9.4%) patients showing a difference larger than 0.5 D in at least one pair of TCA measurements. CONCLUSION: The use of TCA rather than K astigmatism significantly influenced the choice of intraocular lenses (IOLs) as more patients would be candidates for toric IOLs. It was essential to carefully compare and select TCA obtained with multiple methods for optimal postoperative visual quality.

Protocol to examine immune subpopulations in murine conjunctiva and lacrimal gland using flow cytometry.

Here, we present a protocol for the examination of immune cells in the murine conjunctiva and lacrimal gland using flow cytometry. We describe steps for dissection, preparation of high-quality single-cell suspensions, utilization of comprehensive staining panels, and optimization of flow cytometry voltage. We then detail procedures for compensation adjustments and the implementation of effective gating strategies. For complete details on the use and execution of this protocol, please refer to Ma et al.1.

Ocular Biometry Features and Their Relationship with Anterior and Posterior Segment Lengths among a Myopia Population in Northern China.

Objectives: The study aims to explore the ocular biometry of a myopic population in Northern China, focusing specifically on anterior and posterior segment lengths. Methods: This is a cross-sectional study. The medical records of 3458 myopic patients who underwent refractive surgery were evaluated. Axial length (AL), anterior chamber depth (ACD), lens thickness (LT) and other biometric parameters were measured using the IOL Master 700. The study determined the anterior segment length (ASL = ACD + LT), the posterior segment length (PSL = AL - ASL) and the ratio of ASL to PSL (ASL/PSL). Results: This study included 3458 eyes from 3458 myopic patients (1171 men and 2287 women). The mean age was 27.38 ± 6.88, ranging from 16 to 48 years old. The mean ASL was 7.35 ± 0.27 mm, and the mean PSL was 18.39 ± 1.18 mm. The ASL and PSL trends demonstrate an age-related increase for both genders, with notable gender-specific variations. Across most age groups, males typically exhibited higher ASLs and PSLs than females, with the exception of the 35-40 and 40-45 age groups. The ASL and PSL consistently increased with a rising AL. The AL strongly correlates with the PSL and negatively correlates with the ASL/PSL ratio. The ACD and LT moderately correlate with the ASL, but an increased LT does not imply a longer posterior segment. The CCT and SE show little correlation with axial eye parameters. Conclusions: Among Chinese myopic patients, a longer ASL and PSL were correlated with older age and the male gender. The AL strongly correlates positively with the PSL and negatively correlates with the ASL/PSL ratio. An elongation of the posterior segment may primarily account for an eyeball's lengthening.

Interpretable Detection of Diabetic Retinopathy, Retinal Vein Occlusion, Age-Related Macular Degeneration, and Other Fundus Conditions.

Diabetic retinopathy (DR), retinal vein occlusion (RVO), and age-related macular degeneration (AMD) pose significant global health challenges, often resulting in vision impairment and blindness. Automatic detection of these conditions is crucial, particularly in underserved rural areas with limited access to ophthalmic services. Despite remarkable advancements in artificial intelligence, especially convolutional neural networks (CNNs), their complexity can make interpretation difficult. In this study, we curated a dataset consisting of 15,089 color fundus photographs (CFPs) obtained from 8110 patients who underwent fundus fluorescein angiography (FFA) examination. The primary objective was to construct integrated models that merge CNNs with an attention mechanism. These models were designed for a hierarchical multilabel classification task, focusing on the detection of DR, RVO, AMD, and other fundus conditions. Furthermore, our approach extended to the detailed classification of DR, RVO, and AMD according to their respective subclasses. We employed a methodology that entails the translation of diagnostic information obtained from FFA results into CFPs. Our investigation focused on evaluating the models' ability to achieve precise diagnoses solely based on CFPs. Remarkably, our models showcased improvements across diverse fundus conditions, with the ConvNeXt-base + attention model standing out for its exceptional performance. The ConvNeXt-base + attention model achieved remarkable metrics, including an area under the receiver operating characteristic curve (AUC) of 0.943, a referable F1 score of 0.870, and a Cohen's kappa of 0.778 for DR detection. For RVO, it attained an AUC of 0.960, a referable F1 score of 0.854, and a Cohen's kappa of 0.819. Furthermore, in AMD detection, the model achieved an AUC of 0.959, an F1 score of 0.727, and a Cohen's kappa of 0.686. Impressively, the model demonstrated proficiency in subclassifying RVO and AMD, showcasing commendable sensitivity and specificity. Moreover, our models enhanced interpretability by visualizing attention weights on fundus images, aiding in the identification of disease findings. These outcomes underscore the substantial impact of our models in advancing the detection of DR, RVO, and AMD, offering the potential for improved patient outcomes and positively influencing the healthcare landscape.

Evaluation of biometric indicators of anterior segment parameters after ICL implantation by swept-source optical coherence tomography.

BACKGROUND: To evaluate anterior segment structural alterations after implantable collamer lens (ICL) implantation in myopic patients using swept-source quantitative optical coherence tomography (SS-OCT). METHODS: This prospective study included 47 eyes in 24 patients with preoperative spherical equivalent ≥ -3.00 D. Patients underwent ICL implantation at Department of Ophthalmology, Peking University Third Hospital, from May 2021 to December 2022. SS-OCT was used to measure anterior chamber width (ACW), angle opening distance (AOD), angle recess area (ARA), trabecular-iris area (TISA), trabecular-iris angle (TIA), iridotrabecular contact (ITC) area, and ITC Index before ICL implantation surgery and at 1 month follow-up. The correlations among the ITC index, vault, and angle parameters were analysed. Receiver operating characteristic (ROC) analysis was used to explore the ability of the vault to identify eyes with suspected angle-closure. RESULTS: At one month following ICL implantation, the ITC area was 0.396 ± 0.37 mm2, and the ITC index is 8.143 ± 5.439%. All angle parameters, except ACW, showed a statistically significant reduction on SS-OCT (P < 0.05). Mean AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500, and TIA750 values at one month postoperatively decreased by 60.0%, 60.4%, 58.1%, 59.2%, 57.3%, 58.7%, 48.8%, and 50.7%, respectively. The vault was positively correlated with the ITC index and percent change in anterior chamber angle parameters. A vault of > 0.659 mm was found to be optimal for angle-closure suspect with a sensitivity of 85.2% and a specificity of 53.9%. CONCLUSIONS: Anterior chamber angle parameters decreased one month after ICL implantation, and their percentage changes and ITC index correlated with the vault. When the vault is larger than 0.659 mm, it is necessary to be alert to possible closed angle suspicion.

Mapping Resident Immune Cells in the Murine Ocular Surface and Lacrimal Gland by Flow Cytometry.

BACKGROUND: The ocular surface and lacrimal gland have a frontline position in mucosal immunology. However, there have been few updates to the immune cell atlas of these tissues in recent years. PURPOSE: To map the immune cells in murine ocular surface tissues and lacrimal gland. METHODS: Central and peripheral corneas, conjunctiva, and lacrimal gland were dissociated into single cell suspensions, followed by flow cytometry. Discrepancy of immune cells between the central and peripheral corneas was compared. In the conjunctiva and lacrimal gland, myeloid cells were clustered by tSNE and FlowSOM based on the expression of F4/80, Ly6C, Ly6G, and MHC II. ILCs, type 1 immune cells, and type 3 immune cells were analyzed. RESULTS: The number of immune cells in peripheral corneas was about 16 folds of that in central corneas. B cells accounted for 8.74% of immune cells in murine peripheral corneas. In the conjunctiva and lacrimal gland, most myeloid cells tended out to be monocytes, macrophages, and classical dendritic cells (cDCs). ILC3 were 6.28% and 3.63% of ILCs in the conjunctiva and lacrimal gland, respectively. Th1, Tc1, and NK cells were predominant type 1 immune cells. γδ T17 cells and ILC3 outnumbered Th17 cells among type 3 T cells. CONCLUSION: B cells resident in murine corneas were reported for the first time. Additionally, we proposed a strategy of clustering myeloid cells to better understand their heterogeneity in the conjunctiva and lacrimal gland based on tSNE and FlowSOM. Furthermore, we identified the ILC3 in the conjunctiva and lacrimal gland for the first time. Compositions of type 1 and type 3 immune cells were summarized. Our study provides a fundamental reference and novel insights for ocular surface immune homeostasis and diseases.

Prospective clinical study of retinal microvascular alteration after ICL implantation.

Purpose: To evaluate the retinal microvascular alteration after implantable collamer lens (ICL) implantation in moderate to high myopia patients using quantitative optical coherence tomography angiography (OCTA). Methods: This prospective cohort study included 50 eyes of 25 patients with preoperative spherical equivalent ≥ -3.00 D. Patients underwent bilateral ICL implantation at the Department of Ophthalmology, Peking University Third Hospital, from November 2018 to July 2019. OCTA was used to image the superficial and deep retinal capillary plexuses before ICL implantation surgery and at 3 months follow-up. Results: There was no significant difference in the microvascular density within each annular zone and all quadrantal zones of the superficial and deep layers found in myopia patients before and after ICL surgery. Conclusion: Levels of microvascular density in retinal capillary plexuses were stable, as detected by the OCTA, showing the high security of ICL implantation, which would not leave adverse effects on retinal microvasculature in myopia patients.

Progress of Bulbar Conjunctival Microcirculation Alterations in the Diagnosis of Ocular Diseases.

Bulbar conjunctival microcirculation is a microvascular system distributed in the translucent bulbar conjunctiva near the corneal limbus. Multiple ocular diseases lead to bulbar conjunctival microcirculation alterations, which means that bulbar conjunctival microcirculation alterations would be potential screening and diagnostic indicators for these ocular diseases. In recent years, with the emergence and application of a variety of noninvasive observation devices for bulbar conjunctiva microcirculation and new image processing technologies, studies that explored the potential of bulbar conjunctival microcirculation alterations in the diagnosis of ocular diseases have been emerging. However, the potential of bulbar conjunctival microcirculation alterations as indicators for ocular diseases has not been exploited to full advantage. The observation devices, image processing methods, and algorithms are not unified. And large-scale research is needed to concrete bulbar conjunctival microcirculation alterations as indicators for ocular diseases. In this paper, we provide an update on the progress of bulbar conjunctival microcirculation alterations in the diagnosis of ocular diseases in recent five years (from January 2017 to March 2022). Relevant ocular diseases include contact lens wearing, dry eye, conjunctival malignant melanoma, conjunctival nevus, and diabetic retinopathy.