Noninvasive Imaging of Conjunctival Goblet Cells as a Method for Diagnosing Dry Eye Disease in an Experimental Mouse Model.

Purpose: The purpose of this study was to evaluate a noninvasive conjunctival goblet cell (GC) imaging method for assessing dry eye disease (DED) in an experimental mouse model. Methods: Moxifloxacin-based fluorescence microscopy (MBFM) was used to examine GCs noninvasively in 56 mice. Forty-two (42) DED-induced mice were divided into 2 groups and treated topically for 14 days with cyclosporine (CsA) or normal saline (NS). In vivo MBFM imaging and clinical DED evaluations were performed and goblet cell density (GCD) and goblet cell area (GCA) were obtained and compared with histological GCD using periodic acid-Schiff (PAS) staining. Correlation and receiver operating characteristic (ROC) analyses showed MBFM's high diagnostic value. Results: The GCD and GCA of the DED mice obtained from in vivo MBFM imaging were highly correlated with clinical DED parameters and GCD obtained from PAS histology. The therapeutic effect of CsA, as observed by in vivo MBFM, was significant with respect to that of NS treatment. The ROC curves derived from in vivo MBFM showed high diagnostic value in assessing DED. Conclusions: The proposed noninvasive method has high diagnostic value in assessing the severity of DED and the effect of treatment for this disease. Translational Relevance: A noninvasive imaging method using moxifloxacin-based fluorescence microscopy was evaluated for assessing DED in an experimental mouse model. The method showed high diagnostic value in assessing the severity of DED and the effect of treatment, bridging the gap between basic research and clinical treatment. The study provides a promising tool for diagnosing and monitoring DED.

Lymphangiectasia Hemorrhagica Conjunctivae Regression with Bleomycin Sclerotherapy on Anterior-Segment Optical Coherence Tomography.

This case report discusses treatment of lymphangiectasia hemorrhagica conjunctivae with bleomycin sclerotherapy in a patient aged 47 years with a history of recurrent subconjunctival hemorrhage.

Non-invasive hemoglobin estimation from conjunctival images using deep learning.

Hemoglobin, a crucial protein found in erythrocytes, transports oxygen throughout the body. Deviations from optimal hemoglobin levels in the blood are linked to medical conditions, serving as diagnostic markers for certain diseases. The hemoglobin level is usually measured invasively with different devices using the blood sample. In the physical interpretation, some signs are traditionally used. These signs are the palms, face, nail beds, pallor of the conjunctiva, and palmar wrinkles. Studies have shown that conjunctival pallor can yield more effective results in detecting anemia than the pallor of the palms or nail beds. This study is aimed to predict the hemoglobin level by deep learning method, non-invasive, cheap, fast, high accuracy, and without creating medical waste. In this context, conjunctival images and age, weight, height, gender, and hemoglobin values were collected from 388 people who donated blood to the Turkish Red Crescent. A dataset was generated by augmenting the gathered data with body mass index data. Within the scope of this investigation, the limits of agreement (LoA) value at a 95% confidence interval was computed to be 1.23 g/dL, while the bias was established as 0.26 g/dL. The mean absolute percentage error (MAPE) values were determined to be 3.4%, and the root mean squared error (RMSE) was calculated to be 0.68 g/dL. These findings exhibit a successful outcome compared to similar investigations, signifying that this non-invasive method can be employed for hemoglobin level estimation. Furthermore, the estimated hemoglobin levels could aid in diagnosing several hemoglobin-related ailments.

The association between conjunctival and scleral thickness and ocular surface ultraviolet autofluorescence.

Ultraviolet autofluorescence (UVAF) imaging is used to visualise ocular surface changes due to sunlight exposure and so is considered to be a biomarker for UV damage. The conjunctival and scleral thicknesses of participants with and without ocular surface UVAF were measured to examine the UVAF associated tissue thicknesses. The presence of UVAF on the ocular surface was associated with significant differences in tissue thickness including thinner conjunctival epitheliums and thicker scleras but predominantly thickening of the conjunctival stroma. Participants were also classified into four groups according to the presence and absence of UVAF on both the temporal and nasal conjunctivas. It was noted that for those that had only nasal UVAF, the temporal conjunctival stroma was significantly thicker even without the presence of UVAF. Some participants with temporal UVAF had signs of pinguecula observed with slit lamp examination and some had OCT SLO enface imaging darkening. These findings highlight the potential of techniques other than slit lamp examination, including tissue thickness measurement and UVAF photography, in the detection of early UV-related changes to the ocular surface.

Anterior segment optical coherence tomography and ultrasound biomicroscopy in the diagnosis of subconjunctival mycosis mimicking nodular scleritis.

A female patient in her 20s presented with a bulbar conjunctival mass lesion that was diagnosed as nodular scleritis. It was treated with topical and oral steroids in another hospital. Imaging was done using anterior segment optical coherence tomography and ultrasound biomicroscopy, which helped to rule out scleritis and subconjunctival cysticercosis. Histopathology of the excision biopsy specimen revealed fungal filaments. Topical antifungals were started, and the condition resolved without recurrence after therapy. Although rare, infections should be considered in the differential diagnosis of conjunctival mass lesions. Imaging can help to rule out other entities and guide towards appropriate management.

[Bleb morphology using optical coherence tomography : After primary implantation of XEN gel stent and open conjunctival revision]. / Morphologie des Sickerkissens mittels optischer Kohärenztomographie : Nach primärer Implantation von XEN-Gel-Stent und offener Bindehautrevision.

BACKGROUND: The implantation of a XEN gel stent is an innovative method for filtration surgery using an ab interno approach. The morphological evaluation of the resulting bleb is decisive for surgical success. Bleb revision is frequently needed after XEN implantation and might affect the bleb morphology. Aim of this study was to examine bleb morphology using anterior segment OCT (AS-OCT) and analyze the morphological differences of blebs after primary XEN implantation and after bleb revision. MATERIAL AND METHODS: Included were eyes that underwent XEN implantation (Pr-X) or bleb revision after XEN (Re­X group). An AS-OCT of blebs was performed and images were classified using a novel classification system (the Jenaer bleb grading system, JBGS). Frequency of different tomographic patterns (M) and their correlation with intraocular pressure (IOP) were analyzed. RESULTS AND DISCUSSION: A total of 69 eyes (40 in the Pr­X and 29 in the Re­X groups) were included. At the conjunctival level, the most common M in both groups was subconjunctival spaces (M-C2) followed by intraconjunctival cysts (C1) and no conjunctival changes (C0). No differences of frequencies between the two groups or of IOP between the three Ms were seen. At the tenon level, the most commonly seen Ms in the Pr­X group were hyporeflective and cavernous changes (M-T2, T3) followed by no changes (M0) and hyperflective changes (T1). In the Re­X group, the M­T1 and T2 were most commonly seen followed by T3 and T0. The M­T2 and T3 in the Pr­X group and the M­T1 and T2 in the Re­X group correlated with lower IOP. An episcleral lake (M-ES1) was seen significantly less frequently in the Pr­X group compared with Re­X group where it correlated with lower IOP CONCLUSION: The hyperreflective changes at the tenon level and the presence of an episcleral lake were seen more frequently following bleb revision compared with primary XEN implantation and correlated with lower IOP. The interpretation of bleb morphology using AS-OCT should only be done considering the surgical approach used.

[Use of optical coherence tomography angiography in assessment in conjunctival vascular architecture in health and pathology]. / Vozmozhnosti opticheskoi kogerentnoi tomografii v angiorezhime v otsenke angioarkhitektoniki kon"yunktivy v norme i pri patologii.

PURPOSE: Investigation of the capabilities of anterior segment (AS) optical coherence tomography angiography (OCTA) in evaluation of conjunctival vascular architecture in healthy individuals and in various pathological conditions. MATERIAL AND METHODS: The study included 17 healthy volunteers (34 eyes; the control group) and 62 patients (68 eyes) with conjunctival lesions of various nature. All participants underwent AS-OCT and AS-OCTA with assessment of qualitative (vessels pattern, lumen, pathologic tortuosity) and quantitative parameters (vessel density (VD, %) in the lesion area). Mean VD (MVD) and local VD (LVD) were determined, as well as VD in perifocal tissues (PVD). RESULTS: OCTA scans in 8 conjunctival sectors showed mostly radial pattern of the vascular architecture, with vessel lumen remaining the same over their entire visible length. Larger-sized vessels in deeper conjunctival layers were discovered in most cases. The lowest VD value (33.3%) was registered in the superotemporal quadrant, and the highest (38.9%) - in the nasal. Tortuosity of the vessels with course disruption, uneven lumen over the length of the vessels and increase in VD were observed in the area of conjunctival lesions in all cases excluding congenital abnormalities, pingueculae and conjunctival melanocytic intraepithelial neoplasia. The malignant nature of the tumors was indicated by dense vessel distribution and difficulties for visualization of intravascular space, and confirmed by pathohistological analysis. An increase in the number of areas with a lace-like pattern was characteristic for melanomas, with mean VD of more than 50% in the most vascularized areas. CONCLUSION: AS-OCTA is an informative method for the visualization of vessels in healthy conjunctiva and in conjunctival pathology. Local VD in the lesion area should be measured when the vessels are unevenly distributed.

Automated Image Threshold Method Comparison for Conjunctival Vessel Quantification on Optical Coherence Tomography Angiography.

Purpose: To determine the impact of image binarization and the best thresholding method for conjunctival optical coherence tomography angiography (OCTA). Methods: Vessel density (VD) of 14 OCTA conjunctival images (nine nasal and five temporal conjunctivas, and eight right and six left eyes) from normal subjects was analyzed. The binarization of gold-standard images, created by removing pixels that do not represent vessels on ImageJ software, was assessed by three masked graders to determine consistency of VD for images. Various thresholding methods on ImageJ, including manual, 1-, 2- and 3-step processes, were performed on unprocessed images for comparison. Interclass correlation coefficient (ICC) ≥0.750 were classified as good reliability and selected for calculation of the performance of the pixel location in the binarized images of each method. Results: Analysis of the gold-standard threshold method achieved an ICC of 0.816 with excellent agreement (R2 = 0.965, P < 0.001). From a total 28 different methods and variations performed, only nine methods performed with good reliability, including two 1-step thresholds, six 2-step thresholds, and one 3-step threshold method. Overall, 2-step threshold methods were more reliable than 3-step threshold methods. The 2-step method of Bandpass filter + Phansalkar local threshold (LT) showed the best performance with mean pixel accuracy of 86.9% ± 6.8%, area under the curve of 0.826, sensitivity of 79.0%, and specificity 86.1%. Conclusions: Bandpass filter + Phansalkar LT was the best method for VD measurement in conjunctival OCTA. Most commonly reported threshold methods showed unsatisfactory agreement. There is a need in the OCTA field for a standardized method to allow comparison between different studies. Translational Relevance: The proposed threshold method using a widely accessible and commonly used software provides an accurate VD measurement for future OCTA studies.

Transconjunctival Approach: A Safe and Effective Access to Mass Lesions in the Anterior Orbit.

BACKGROUND: The orbit is an eloquent organ of the body. Safe surgical access to the orbit could be challenging due to the dense network of critical structures confined to it. There are versatile approaches to different parts of the orbit that could be used by neurosurgeons without causing injury to critical neurovascular structures. In this study, we aimed to present our surgical experience with the transconjunctival approach through the bulbar conjunctiva to anterior intraorbital lesions caused by diverse pathologies. METHODS: We conducted a retrospective review of cases with intraorbital lesions operated via the transconjunctival approach by the same senior surgeon between 2015 and 2017. All patients were evaluated before the surgery by computed tomography, magnetic resonance imaging, and plain anteroposterior and lateral radiographs. RESULTS: Five patients underwent surgery by the transconjunctival approach through the medial or lateral routes for different pathologies: cavernoma, lymphoma, inflammatory reaction, meningocele, and foreign body. No complications were recorded, and all patients were satisfied with their clinical and esthetic results. CONCLUSIONS: The transconjunctival approach is a safe, effective, and time-sparing surgical approach to diverse pathologies in the anterior orbit. Navigation systems enhance the ability to maneuver in selected cases. The transconjunctival approach could be performed in collaboration with ophthalmologists since it provides better esthetic outcomes and higher satisfaction rates in operated patients.

Moxifloxacin-Based Extended Depth-of-Field Fluorescence Microscopy for Real-Time Conjunctival Goblet Cell Examination.

Conjunctival goblet cells (CGCs) are mucin-secreting cells in the eye and play essential roles for ocular surface homeostasis. Since various ocular surface pathologies are related to CGC dysfunction, CGC examination is important for the evaluation of ocular surface conditions. Recently we introduced moxifloxacin-based fluorescence microscopy (MBFM) for non-invasive CGC imaging. However, the imaging speed was up to 1 frame per second (fps) and needed to be improved for clinical applications. In this study, we developed a high-speed moxifloxacin-based, extended depth-of-field (EDOF) microscopy system that operates at a maximum imaging speed of 15 fps. The system used a deformable mirror for the high-speed axial sweeping of focal plane during single-frame acquisitions. The acquired images contained both in-focus and out-of-focus information, and deconvolution was used to filter the in-focus information. The system had a DOF of 800 [Formula: see text], field-of-view of 1.2 mm ×1.2 mm, and resolution of [Formula: see text]. Its performance was demonstrated by real-time, breathing-motion-insensitive CGC imaging of mouse and rabbit models, in vivo. High-speed EDOF microscopy has potentials for non-invasive, real-time CGC examinations of human subjects.

ANALYSIS OF CONJUNCTIVAL VASCULAR DENSITY IN SCLERAL CONTACT LENS WEARERS USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

PURPOSE: To investigate conjunctival vascular density (VD) using Anterior Segment Optical Coherence Tomography Angiography (OCTA) in Scleral Contact Lens (ScCL) wearers. METHODS: In this cross-sectional study, the conjunctival blood VD was assessed using OCTA with an anterior segment lens adapter. The nasal surface of each eye (6 ×6 mm) was scanned to a depth of 800 µm with ScCL and fifteen minutes after removing the lens. Conjunctival VD was defined as the percentage of the scanned volume occupied by vessels in which blood flow was measured. Measures of limbal indentation were subjectively determined by two independent observers using Anterior Segment Optical Coherence Tomography (AS-OCT). Comparisons between VD measurements before and after ScCL removal and correlations between conjunctival VD, time of use, vault and indentation values were also investigated. RESULTS: A total of 23 patients (3 females, 20 males) with keratoconus, with a mean age (years±SD) of 38.74±10.38 were included in the study. VD was significantly higher without ScCL (71.75%±2.97) than VD measured with ScCL (69.81%±2.63), p=0.02. A moderately negative correlation was found between indentation and vault (r=-0.44, p<0.05) and a positive tendency regarding the time of wearing ScCL and indentation (r=0.11 and r=0.068, respectively). CONCLUSIONS: Using OCTA with an anterior segment lens adapter, the ocular surface blood VD was imaged and assessed with good repeatability and reliability. This study presents a new possible application of OCTA to investigate and monitor conjunctival vasculature in ScCL wearers. This results cautiously suggest that the repeated use of ScCL can cause vascular alterations in conjunctiva of the eyes of ScCL wearers, possibly due to a hidden hypoxia caused by prolonged limbal indentation.

The role of 18F-FDG PET/CT in diagnosis and treatment evaluation for ocular adnexal mucosa-associated lymphoid tissue lymphoma.

OBJECTIVE: The purpose of this study is to evaluate the value of fluorine-18-fludeoxyglucose positron emission tomography (18F-FDG PET)/CT in the diagnosis and treatment evaluation of ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphoma. METHODS: 70 patients with OAML who received radiotherapy were recruited in our study. All the patients had the 18F-FDG PET/CT examination before the treatment. We retrospectively reviewed the medical records, pathological reports, laboratory results, and imaging features of all patients. The associations between 18F-FDG PET/CT parameters and Epstein-Barr virus antibodies, treatment response, MRI data, and Ki-67 expression were investigated. RESULTS: The PET/CT scan indicated that 80% (56/70) of the patients showed orbital FDG avidity. The median level of maximum standardized uptake value (SUVmax) of the lesions was 4.65 ± 3.00 (range:1.2-13.5). 92.0% (46/50) of the mass-forming lesions showed 18F-FDG avidity, while only 50.0% (10/20) of the non-massive lesions had 18F-FDG avidity (χ2 = 13.23, p=0.01). The SUVmax in orbit, conjunctiva, and lacrimal gland lymphoma were 5.6, 2.9, and 3.7, respectively. A significant difference was identified of SUVmax among the three locations' lymphoma using one-way ANOVA analysis (F = 5.039, p = 0.01). After completion of radiotherapy, the complete remission rate was achieved in 30.8% (4/13) of the patients without 18F-FDG avidity, and 70.4% (38/54) in cases with 18F-FDG avidity (χ2 = 5.43, p = 0.02). The correlation between high Ki-67 score and 18F-FDG avidity was confirmed (χ2 = 3.916, p = 0.048); however, no significant correlation was found between the SUVmax and Ki-67 score of the lesions (p = 0.971). Three patients (3/70, 4.3%) were upregulated the stage via PET/CT. CONCLUSION: 18F-FDG PET/CT had some potential values in the diagnosis and assessment of treatment response in patients with OAML. ADVANCES IN KNOWLEDGE: The value of 18F-FDG PET/CT for patients with OAML.

Changes in Limbal Optical Coherence Tomography Angiography Outcomes in Patients With Overnight Contact Lens Wear.

OBJECTIVES: To evaluate the perilimbal vasculature of patients who wear contact lenses (CLs) overnight with optical coherence tomography angiography (OCTA) and compare the results with healthy population. METHODS: Forty-two patients were included in this observational study. The OCTA imaging was performed in the temporal quadrant of the perilimbal region using a swept-source optical coherence tomography system (Triton DRI-OCT; Topcon Corporation, Tokyo, Japan). The assessments were made in two depths: starting from the conjunctival epithelium to 200 µm scleral depth and the scleral depth between 200 and 1,000 µm. The vessel density, vessel length density, vessel diameter index, and fractal dimension were the main outcomes and compared between overnight CL users and healthy population. RESULTS: Twenty-two patients who have been using CLs overnight for at least 3 months and 20 healthy individuals were included in the study. The vessel density at the superficial layer was significantly higher in the CL group compared with the control group (P<0.001). Vessel diameter index, vessel length density, and fractal dimension at the superficial layer did not differ between the groups (P>0.05 for all). There was no difference in the vessel density, vessel diameter index, vessel length density, and fractal dimension in the deep layer between the groups (P>0.05 for all). CONCLUSIONS: Patients who use CL overnight exhibit increased vessel density in the superficial layers of the perilimbal region, which may suggest new vessel formation in the conjunctiva. Anterior segment OCTA may be useful to evaluate the initial changes in limbal vasculature in CL users.

Quantification of Blood Flow Velocity in the Human Conjunctival Microvessels Using Deep Learning-Based Stabilization Algorithm.

The quantification of blood flow velocity in the human conjunctiva is clinically essential for assessing microvascular hemodynamics. Since the conjunctival microvessel is imaged in several seconds, eye motion during image acquisition causes motion artifacts limiting the accuracy of image segmentation performance and measurement of the blood flow velocity. In this paper, we introduce a novel customized optical imaging system for human conjunctiva with deep learning-based segmentation and motion correction. The image segmentation process is performed by the Attention-UNet structure to achieve high-performance segmentation results in conjunctiva images with motion blur. Motion correction processes with two steps-registration and template matching-are used to correct for large displacements and fine movements. The image displacement values decrease to 4-7 µm during registration (first step) and less than 1 µm during template matching (second step). With the corrected images, the blood flow velocity is calculated for selected vessels considering temporal signal variances and vessel lengths. These methods for resolving motion artifacts contribute insights into studies quantifying the hemodynamics of the conjunctiva, as well as other tissues.

An Update on COVID-19 Related Ophthalmic Manifestations.

Purpose: To summarize ophthalmic manifestations of coronavirus disease (COVID-19) reported in the literature thus far.Methods: The PubMed database was systematically searched through October 24, 2020, to identify relevant articles using the following search terms: ("COVID-19" OR "SARS-CoV-2") AND ("eye" OR "ophthalmology" OR "retina" OR "retinal findings" OR "cornea" OR "conjunctiva"). Only articles published in English were included in this review.Results: The reported prevalence of ophthalmic manifestations is generally low, but correlates positively with the severity of the disease. Most commonly reported ocular manifestations are conjunctivitis, conjunctival hyperemia and chemosis. Retinal findings include microhemorrhages and flame-shaped hemorrhages, cotton wool spots, dilated veins, and tortuous vessels.Conclusion: Considering the COVID-19 cases have reached pandemic dimensions and are surging, yet again, it is of utmost importance to determine its ophthalmic manifestations and prevent their vision threatening complications. Further studies are warranted to establish whether the retinal findings appear due to the COVID-19 or are an incidental finding in patients with a preexisting diabetic or hypertensive retinopathy.

A prospective multicentre study of intravitreal injections and ocular surface in 219 patients: IVIS study.

PURPOSE: To assess the impact of intravitreal injections (IVTI) on ocular surface of patients treated with multiple injections. METHODS: Prospective, tricentric study conducted in patients treated with unilateral IVTI. An asepsis protocol with povidone-iodine was used for all patients during IVTI. The primary endpoint was the difference between the pre-IVTI Ocular Surface Disease Index (OSDI 1) score and that measured on day one (D1) post-IVTI (OSDI 2). Secondary endpoints were the evaluation of predictive factors for OSDI scores, pain assessment on D1, and the Lacrydiag® analysis of tears from the injected eye versus contralateral eye before IVTI. RESULTS: Two hundred and nineteen patients with a mean age of 75.9 ± 10 years were included. The mean OSDI2-OSDI1 difference was 19.2 ± 20.6 (p < 0.001). The mean noninvasive tear break-up time was 6.41 ± 4.59 seconds in the injected eye versus 7.36 ± 4.36 seconds in the contralateral eye (p < 0.001). In the multivariate analysis, the factors significantly associated with the OSDI 2 score were the OSDI 1 score (p < 0.001), the pain score on D1 (p < 0.001) the number of instilled glaucoma eye drop (p = 0.01) and a centre effect (centres 2 and 3 versus centre 1, p < 0.001). CONCLUSION: Our results confirm the impairment of the ocular surface and quality of life immediately after an IVTI. These results suggest 3 levels of action to improve the immediate tolerance: improving the basal status of the ocular surface, reducing the contact time with povidone-iodine that might be toxic to the surface, and improving immediate post-IVTI treatment.