Search Results (11)

Backgrounds/Objectives: The aim of this study was to compare differences in the physical characteristics of lissamine green (LG) strips and the outcomes of using different staining techniques. Methods: Two separate complementary investigations were conducted. Physical study: Differences between four LG strips were evaluated in terms of material, dye concentration, and dye absorption. In vivo study: Bulbar conjunctival staining was compared for four application methods of I-DEW LG strips presented in a randomized order for twenty-two participants: (1) single application 5 s after wetting (also repeated using GreenGlo for comparison), (2) single application using two strips held together, 5 s after wetting, (3) two applications using a single LG strip 5 s after wetting, 1 minute apart, (4) the same as method 3, with a single fluorescein strip in between LG applications. White light imaging was performed immediately following application and after 30, 60, 90, and 300 s. Three masked practitioners independently evaluated the randomized staining images for spot count and staining intensity. Results: Physical study: Strip paper fibres demonstrated visible similarities, with no difference in saline absorption (p > 0.05). LG concentration increased as saline retention duration increased (F = 964.1, p < 0.001), and GreenGlo tips were significantly darker (F = 2775.2, p < 0.001). In vivo study: I-DEW application resulted in less conjunctival staining than GreenGlo (p < 0.001). Amongst I-DEW application techniques, staining levels were similar (p > 0.05); however, staining intensity was significantly higher following two applications of I-DEW, 1 min apart, compared to a single application (p = 0.042). Both spot count and staining intensity decreased with time (p < 0.001). Conclusions: Two applications of I-DEW using a single strip, 1 min apart, after wetting with a single drop of saline provided maximal staining. There was also a significant difference in staining intensity observed between LG products. Full article

Allergic conjunctivitis (AC) is the most common allergic eye disorder. Antiallergic eyedrops are the first line of pharmacological treatment. However, the application of antiallergic eyedrops can potentially alter tear homeostasis and affect the ocular surface, which may result in iatrogenic diseases such as dye eye disease (DED). Long-term treatment of AC with eyedrops containing preservatives and other components may increase the risk of DED and ocular surface damage. Here, we examined 20 clinical trials published during the past ten years with antihistamine ophthalmic formulations in the treatment of AC, to evaluate the extent of evidence about their safety and tolerability. Remarkably, we find that most trials lack an evaluation of the critical ocular surface parameters, such as tear film break-up time, tear volume, corneal and conjunctival damage, and inflammation, to properly assess the state of the ocular surface state after prolonged treatment. There is a need to increase awareness of the use of specific formulations that do not increase the risk of iatrogenic DED. Full article

The development of choroidal neovascularization (CNV) is a crucial factor in the pathophysiology and prognosis of exudative age-related macular degeneration (AMD). Therefore, the detection of CNV is essential for establishing an appropriate diagnosis and treatment plan. Current ophthalmic imaging techniques, such as fundus fluorescent angiography and optical coherence tomography, have limitations in accurately visualizing CNV lesions and expressing CNV activity, owing to issues such as excessive dye leakage with pooling and the inability to provide functional information. Here, using the arginine−glycine−aspartic acid (RGD) peptide’s affinity for integrin α_vβ₃, which is expressed in the neovascular endothelial cells in ocular tissues, we propose the use of fluorescein isothiocyanate (FITC)-labeled RGD peptide as a novel dye for effective molecular imaging of CNV. FITC-labeled RGD peptides (FITC-RGD₂), prepared by bioconjugation of one FITC molecule with two RGD peptides, demonstrated better visualization and precise localization of CNV lesions than conventional fluorescein dyes in laser-induced CNV rodent models, as assessed using various imaging techniques, including a commercially available clinical fundus camera (Optos). These results suggest that FITC-RGD₂ can serve as an effective novel dye for the diagnosis of neovascular retinal diseases, including AMD, by enabling early detection and treatment of disease occurrence and recurrence after treatment. Full article

There is a significant unmet need for therapeutics to treat ocular surface barrier damage, also called epitheliopathy, due to dry eye and related diseases. We recently reported that the natural tear glycoprotein CLU (clusterin), a molecular chaperone and matrix metalloproteinase inhibitor, seals and heals epitheliopathy in mice subjected to desiccating stress in a model of aqueous-deficient/evaporative dry eye. Here we investigated CLU sealing using a second model with features of ophthalmic preservative-induced dry eye. The ocular surface was stressed by topical application of the ophthalmic preservative benzalkonium chloride (BAC). Then eyes were treated with CLU and sealing was evaluated immediately by quantification of clinical dye uptake. A commercial recombinant form of human CLU (rhCLU), as well as an rhCLU form produced in our laboratory, designed to be compatible with U.S. Food and Drug Administration guidelines on current Good Manufacturing Practices (cGMP), were as effective as natural plasma-derived human CLU (pCLU) in sealing the damaged ocular surface barrier. In contrast, two other proteins found in tears: TIMP1 and LCN1 (tear lipocalin), exhibited no sealing activity. The efficacy and selectivity of rhCLU for sealing of the damaged ocular surface epithelial barrier suggests that it could be of therapeutic value in treating BAC-induced epitheliopathy and related diseases. Full article

Although fundus fluorescein angiography (FFA) is a very effective retinal imaging tool for ophthalmic diagnosis, the requirement of intravenous injection of harmful fluorescein dye limits its application. As a screening diagnostic method that reduces the frequency of intravenous injection, a series-parallel generative adversarial network (GAN) architecture for translating fundus structure image to FFA images is proposed herein, using deep learning-based software that only needs an intravenous injection for the training process. Firstly, the fundus structure image and the corresponding FFA images of three phases are collected. Secondly, our series-parallel GAN is trained to translate FFA images from fundus structure image with the supervision of FFA images. Thirdly, the trained series-parallel GAN model is used to translate FFA images by only using fundus structure image. By comparing the FFA images translated by our algorithm, Sequence GAN, pix2pix, and cycleGAN, we show the advancement of our algorithm. To further confirm the advancements of our algorithm, we evaluate the peak signal-to-noise ratio (PSNR), structural similarity (SSIM) index, and mean-squared error (MSE) of our algorithm, Sequence GAN, pix2pix, and cycleGAN. To demonstrate the performance of our method, we show some typical FFA images translated by our algorithm. Full article

Purpose: To examine the physicochemical properties of five preservative-free (PF) 0.005% latanoprost ophthalmic products; Monoprost^®, Latanest^®, Gaap Ofteno^®, Xalmono^®, and Xaloptic^® Free. Furthermore, the study investigated the mucin production and cell survival of primary cultured human conjunctival goblet cells when treated with PF eye drops. Method: The pH value, osmolality, and surface tension were examined. Cell survival was analyzed using lactate dehydrogenase and tetrazolium dye colorimetric assays. Mucin production was analyzed with immunohistochemical staining. Results: Monoprost^® (pH value 6.84 ± 0.032) had a pH value closest to the pH value of tear fluid (pH value 7.4–7.6), whereas Gaap Ofteno^® (pH value 6.34 ± 0.004) and Latanest^® (pH value 6.33 ± 0.003) had the lowest pH values. Gaap Ofteno^® (325.9 ± 2.9 mosmol/kg) showed iso-osmolar probabilities, whereas the other products were hypo-osmolar. Gaap Ofteno^® (60.31 ± 0.35 mN/m) had a higher surface tension compared to the tear fluid (40 to 46 mN/m), as described in the literature. No significant differences in goblet cell survival or mucin release were observed between the treatments and control. Conclusion: Significant differences in pH value, osmolality, and surface tension were observed. However, this did not affect the viability of the goblet cells or the release of mucin. Clinical studies are required to evaluate the long-term effects of use on efficacy and safety. Full article

In standing ophthalmic surgery in horses, a retrobulbar nerve block (RNB) is often placed blindly for anesthesia and akinesia. The ultrasound (US)-guided RNB may have fewer complications, but the two techniques have only been compared once in equine cadavers. This study compares the techniques for success and complication rates and analyzes the effect of training on US guidance. Twenty-two equine cadavers were divided into three groups: blind RNBs were performed bilaterally in eight cadavers, US-guided RNBs were performed bilaterally in seven cadavers, and after US-guided training, blind RNBs were performed bilaterally in seven cadavers. All RNBs were performed by the same two inexperienced operators, and a combination of contrast medium (CM; 1.25 mL) and methylene blue dye (1.25 mL) were injected (2.5 mL total volume). Needle positioning in the periorbita and the distance of the CM to the optic foramen were assessed using computerized tomography (CT). Dye spreading was evaluated by dissection. In group 1, 37.5% of the injections were in the optimal central position in the periorbita; in group 2, 75% and in group 3, 71.4%. There was no significant difference between the groups regarding needle position (groups 1 and 2 p = 0.056; groups 1 and 3 p = 0.069, groups 2 and 3 p = 0.8). The mean CM distribution distance was not significantly different between all groups. Group 1 had 18.75% intraocular injections versus 0% in group 2 and 7.1% in group 3 (not significant). US guidance showed no significant increases in accuracy nor decreases in complications. However, the effects on accuracy showed a trend towards significant improvement, and larger scale follow-up studies might show significant training effects on US guidance. Full article

Rose bengal has been used in the diagnosis of ophthalmic disorders and liver function, and has been studied for the treatment of solid tumor cancers. To date, the antibacterial activity of rose bengal has been sporadically reported; however, these data have been generated with a commercial grade of rose bengal, which contains major uncontrolled impurities generated by the manufacturing process (80–95% dye content). A high-purity form of rose bengal formulation (HP-RBf, >99.5% dye content) kills a battery of Gram-positive bacteria, including drug-resistant strains at low concentrations (0.01–3.13 μg/mL) under fluorescent, LED, and natural light in a few minutes. Significantly, HP-RBf effectively eradicates Gram-positive bacterial biofilms. The frequency that Gram-positive bacteria spontaneously developed resistance to HP-RB is extremely low (less than 1 × 10⁻¹³). Toxicity data obtained through our research programs indicate that HP-RB is feasible as an anti-infective drug for the treatment of skin and soft tissue infections (SSTIs) involving multidrug-resistant (MDR) microbial invasion of the skin, and for eradicating biofilms. This article summarizes the antibacterial activity of pharmaceutical-grade rose bengal, HP-RB, against Gram-positive bacteria, its cytotoxicity against skin cells under illumination conditions, and mechanistic insights into rose bengal’s bactericidal activity under dark conditions. Full article

The present study aims to evaluate the efficacy of a novel drug delivery system of the modified rice hydrogel containing praziquantel (PZQ) against Philophthalmus gralli isolated from ostrich eyes and determine the toxicity of the preparation on chicken eye model. The parasiticidal activity of PZQ (0, 1, 10, and 100 µg/mL) was tested on P. gralli. The ophthalmic antiparasitic hydrogel was formulated with appropriate amount of PZQ and chemically modified rice gel. The parasitic morphology after exposure with the preparation was examined under scanning electron microscope (SEM). The anthelminthic efficacy of the preparation on motility and mortality of parasites was performed by visual inspection and vital dye staining. The ocular irritation of the preparation was evaluated for 21 days using standard avian model followed by OECD 405. The results demonstrated that the parasiticidal activity of PZQ against P. gralli appears to be in a concentration- and time-dependent manner. In addition, the concentration of PZQ 10 µg/mL (Chi squared test, p = 0.003) and exposure time for 24 h (log-rank test, p = 0.0004) is sufficient to kill parasites, when statistically compared to negative control group. Rice hydrogel containing a lethal concentration of 10 µg/mL PZQ was successfully prepared. The preparation illustrated good parasitic killing and motile inhibiting effect on P. gralli compared with PZQ 10 µg/mL and its control (p < 0.05). An appearance under SEM of non-viable parasite after being incubated with the preparation, showing parasitic deformity, was observed comparing with the viable parasite in 0.9% normal saline solution (NSS). Moreover, no irritation of chicken eyes was also observed. Our results contribute to understanding the efficacy and the safety of the rice hydrogel of PZQ which have a predictive value for controlling P. gralli on the animal eyes. However, the pharmacological application needs to be further investigated for the best possible therapeutic approach. Full article

The optical coherence tomography angiography (OCTA) is a noninvasive imaging technology which aims at imaging blood vessels in retina by studying decorrelation signals between multiple sequential OCT B-scans captured in the same cross section. Obtaining various vascular plexuses including deep and superficial choriocapillaris, is possible, which helps in understanding the ischemic processes that affect different retina layers. OCTA is a safe imaging modality that does not use dye. OCTA is also fast as it can capture high-resolution images in just seconds. Additionally, it is used in the assessment of structure and blood flow. OCTA provides anatomic details in addition to the vascular flow data. These details are important in understanding the tissue perfusion, specifically, in the absence of apparent morphological change. Using these anatomical details along with perfusion data, OCTA could be used in predicting several ophthalmic diseases. In this paper, we review the OCTA techniques and their ability to detect and diagnose several retinal vascular and optical nerve diseases, such as diabetic retinopathy (DR), anterior ischemic optic neuropathy (AION), age-related macular degeneration (AMD), glaucoma, retinal artery occlusion and retinal vein occlusion. Then, we discuss the main features and disadvantages of using OCTA as a retinal imaging method. Full article

Purpose: The purpose of this study was to develop an advanced in vitro blink model that can be used to examine the release of a wide variety of components (for example, topical ophthalmic drugs, comfort-inducing agents) from soft contact lenses. Methods: The model was designed using computer-aided design software and printed using a stereolithography 3D printer. The eyelid and eyeball were synthesized from polyvinyl alcohol and silicone material, respectively. Simulated tear fluid was infused through tubing attached to the eyelid using a syringe pump. With each blink cycle, the eyelid slides and flexes across the eyeball to create an artificial tear film layer. The flow-through fluid was collected using a specialized trough. Two contact lenses, etafilcon A and senofilcon A, were incubated in 2 mL of a water-soluble red dye for 24 h and then placed on the eye model (n = 3). The release of the dye was measured over 24 h using a tear flow rate of 5 µL/min. Results: Approximately 25% of the fluid that flowed over the eye model was lost due to evaporation, nonspecific absorption, and residual dead volume. Senofilcon A absorbed more dye (47.6 ± 2.7 µL) than etafilcon A (22.3 ± 2.0 µL). For etafilcon A, the release of the dye followed a burst-plateau profile in the vial but was sustained in the eye model. For senofilcon A, the release of the dye was sustained in both the vial and the eye model, though more dye was released in the vial (p < 0.05). Overall, the release of the dye from the contact lenses was higher in the vial compared with the eye model (p < 0.05). Conclusion: The blink model developed in this study could be used to measure the release of topical ophthalmic drugs or comfort agents from contact lenses. Simulation of a blink mechanism, an artificial tear film, and nonspecific absorption in an eye model may provide better results than a simple, static vial incubation model. Full article