A novel simulation model for corneal gluing.
Ontology highlight
ABSTRACT:
SUBMITTER: Fu L
PROVIDER: S-EPMC9873907 | biostudies-literature | 2023 Feb
REPOSITORIES: biostudies-literature
Publications
A novel simulation model for corneal gluing.
Fu Lanxing L Hollick Emma J EJ
Eye (London, England) 20220801 2
Similar Datasets
Project description: Not available
| S-EPMC10810859 | biostudies-literature
Project description:Cyanoacrylate glue (CG) is a commonly employed modality for sealing small corneal perforations. Presently, we describe the technique of emulsion polymer isocyanate (EPI)-gluing, a modification of its application, and its results in nine eyes with noninfectious, nontraumatic sterile corneal perforation with size ≤3 mm. The method involves harvesting a small patch of autologous epithelium adjacent to the melt area with the help of 10% alcohol and transplanting to the site of melt with its basement membrane facing downwards. CG, loaded on the reverse side of Sinskey hook or Weck-Cel sponge, is instilled on this epithelium-melt site complex and withdrawn immediately following which a bandage contact lens is placed on the corneal surface. In our series of patients with nine eyes where EPI-gluing was undertaken, all eyes reported a healed corneal scar with spontaneously dislodged glue and no underlying vascularization at 3-months follow-up. EPI-gluing is an inexpensive and host-friendly technique for the treatment of small noninfectious corneal perforations particularly with iris tissue prolapse.
| S-EPMC7640831 | biostudies-literature
Project description: Not available
| S-EPMC10482947 | biostudies-literature
Project description:Corneal opacities affect vision for millions of individuals worldwide. Fibrotic scar tissues accumulate in reaction to inflammatory responses and remain permanently in corneal stroma, and conventionally correctable only by donor corneal transplantation. Numerous studies have explored innovative approaches to reverse corneal scarring through non-surgical means; however, existing mouse models limit these studies, due to the lack of visibility of scar tissue in mouse corneas with steep curvature. Here, we reported that corneal scarring was modelled using a transgenic mouse line, Tg(Col3a1-EGFP)DJ124Gsat, in which enhanced green fluorescence protein (EGFP) reporter expression was driven by the promoter of collagen 3a1 (COL3a1), a stromal fibrosis gene. Similar to wildtype, Col3a1-EGFP transgenic corneas developed opacities after wounding by alkali burn and mechanical ablation, respectively, as examined under stereomicroscopy and Spectral Domain optical coherent tomography. The time course induction of EGFP was aligned with Col3a1 upregulation and matched with the elevated expression of other fibrosis genes (α-smooth muscle actin, fibronectin and tenascin C). Measured by flow cytometry and enzyme-linked immunosorbent assay, increased number of EGFP expressing cells and fluorescent intensities were correlated to corneal thickening and scar volume. After treatment with human corneal stromal stem cells or their exosomes, EGFP expression was downregulated together with the reduction of scar volume and fibrosis gene expression. These results have demonstrated that the transgenic mouse line, Tg(Col3a1-EGFP)DJ124Gsat, can be a valuable tool for the detection of corneal fibrosis and scarring in vivo, and will be useful in monitoring the changes of corneal fibrosis over time.
| S-EPMC7655566 | biostudies-literature
Project description: Not available
| S-EPMC8837378 | biostudies-literature
Project description:IntroductionNeuropathic pain arises as a result of peripheral nerve injury or altered pain processing within the central nervous system. When this phenomenon affects the cornea, it is referred to as neuropathic corneal pain (NCP), resulting in pain, hyperalgesia, burning, and photoallodynia, severely affecting patients' quality of life. To date there is no suitable animal model for the study of NCP. Herein, we developed an NCP model by constriction of the long ciliary nerves innervating the eye.MethodsMice underwent ciliary nerve constriction (CNC) or sham procedures. Safety was determined by corneal fluorescein staining to assess ocular surface damage, whereas Cochet-Bonnet esthesiometry and confocal microscopy assessed the function and structure of corneal nerves, respectively. Efficacy was assessed by paw wipe responses within 30 seconds of applying hyperosmolar (5M) saline at Days 3, 7, 10, and 14 post-constriction. Additionally, behavior was assessed in an open field test (OFT) at Days 7, 14, and 21.ResultsCNC resulted in significantly increased response to hyperosmolar saline between groups (p < 0.0001), demonstrating hyperalgesia and induction of neuropathic pain. Further, animals that underwent CNC had increased anxiety-like behavior in an open field test compared to controls at the 14- and 21-Day time-points (p < 0.05). In contrast, CNC did not result in increased corneal fluorescein staining or decreased sensation as compared to sham controls (p > 0.05). Additionally, confocal microscopy of corneal whole-mounts revealed that constriction resulted in only a slight reduction in corneal nerve density (p < 0.05), compared to naïve and sham groups.DiscussionThe CNC model induces a pure NCP phenotype and may be a useful model for the study of NCP, recapitulating features of NCP, including hyperalgesia in the absence of ocular surface damage, and anxiety-like behavior.
| S-EPMC10749205 | biostudies-literature
Project description:PurposeSurgical simulation of microvascular anastomosis has become increasingly popular. There are several living and silicone models available. Current silicone models fail to accurately reproduce a vessel's loose adventitial layer, which may lead to the development of improper microsurgical technique. Our purpose is to create a realistic 3-dimensional microsurgical simulator that incorporates an adventitial vessel layer for higher fidelity manipulation of vessels.MethodsA microvascular anastomosis simulator was manufactured using metal moulds and inorganic materials. Synthetic tubing was created with a metal cylinder, 1.65 mm in diameter, painted with 2 sequential layers of silicon with a shore hardness of 2A. Silicone was allowed to fully cure in-between layers. Vessel adventitia was created with a 100-micron polyester mesh adhered to the silicone vessel exterior. Once dry, the synthetic tube is removed from the metal cylinder is then clipped to reveal the inner lumen. Both Resident and attending physicians evaluated the model with and without the adventitial layer and completed a questionnaire.ResultsGrasping and manipulation of the vessel were scored on Average score 4.5 and 3 out of 5, with adventitia and without, respectively (P = .00906). Usefulness as a teaching tool was scored on average 4.9 and 4.2, with adventitia and without, respectively (P = .0232). The analysis included: simulation realism, educational utility, and overall satisfaction. Responses in all domains were favourable, suggesting the utility of this model.ConclusionWe created a realistic, high fidelity microvascular anastomosis simulator that is low cost and easily reproducible. Initial feedback is encouraging regarding realism, educational utility, and overall usefulness. Further validation is required to assess its effectiveness in resident education and skill transfer to the operating room.
| S-EPMC9096860 | biostudies-literature
Project description:BACKGROUND: Simulation is an effective method for teaching clinical skills but has not been widely adopted to educate trainees about how to teach. OBJECTIVE: We evaluated a curriculum for pediatrics fellows by using high-fidelity simulation (mannequin with vital signs) to improve pedagogical skills. INTERVENTION: The intervention included a lecture on adult learning and active-learning techniques, development of a case from the fellows' subspecialties, and teaching the case to residents and medical students. Teaching was observed by an educator using a standardized checklist. Learners evaluated fellows' teaching by using a structured evaluation tool; learner evaluations and the observer checklist formed the basis for written feedback. Changes in fellows' pedagogic knowledge, attitudes, and self-reported skills were analyzed by using Friedman and Wilcoxon rank-sum test at baseline, immediate postintervention, and 6-month follow-up. RESULTS: Forty fellows participated. Fellows' self-ratings significantly improved from baseline to 6-month follow-up for development of learning objectives, effectively reinforcing performance, using teaching techniques to promote critical thinking, providing constructive feedback, and using case studies to teach general rules. Fellows significantly increased agreement with the statement "providing background and context is important" (4.12 to 4.44, P = .02). CONCLUSIONS: Simulation was an effective means of educating fellows about teaching, with fellows' attitudes and self-rated confidence improving after participation but returning to baseline at the 6-month assessment. The simulation identified common weaknesses of fellows as teachers, including failure to provide objectives to learners, failure to provide a summary of key learning points, and lack of inclusion of all learners.
| S-EPMC3963769 | biostudies-other
Project description:IntroductionLive-animal-free ocular toxicity models and tests are a necessity in multiple branches of medicine, industry and science. Corneal models with adjustable ranges of injury severities do not exist. In this work, a novel and precise and dose - response method to induce and observe ex vivo corneal chemical burns has been established.MethodsThe EVEIT (Ex Vivo Eye Irritation Test) is based on an ex vivo corneal organ model for rabbit corneas from food industry. Further, a highly precise three - axis workstation has been employed to apply liquid corrosive, sodium hydroxide (NaOH), droplets in a nanolitre (nL) range onto the corneal surface. Optical Coherence Tomography (OCT) has been used to observe and quantify the elicited changes in the corneal layers.ResultsThe speed and intervals of single nanodroplet application played a crucial role in the extent of the corneal changes. Similar total volumes applied at low frequencies elicited deep and extensive changes in the corneal layers whereas high application frequencies elicited comparatively superficial changes. Increasing NaOH concentrations effected measurably increasing corneal changes. Increasing the volume of applied NaOH also showed an increase in corneal changes.ConclusionsOCT imaging proved to be effective in observing, documenting and quantifying the changes in the corneal layers. The ex vivo model, in conjunction with the novel application method was able to induce and display distinctive and consistent correlations between NaOH volume, concentration and elicited corneal changes. This ex vivo ocular chemical burn model provides a consistent in vitro basis for pharmaceutical and toxicological experiments and investigations into corneal chemical burn mechanisms and treatment.
| S-EPMC8215138 | biostudies-literature
Project description:Drug delivery by topical application has higher patient acceptance and lower morbidity than intraocular injection, but many ophthalmic treatments are unable to enter the eye or reach the posterior segment after topical application. The first stage towards posterior segment delivery after topical application is ocular surface penetration and existing models are in vivo or use large quantities of tissue. We therefore developed a novel ex vivo model using discs of porcine and human cornea and sclera (5 mm diameter) to assess penetration of a candidate neuroprotective siRNA. siRNA against caspase 2 or control solutions of known penetrance were applied to the corneal epithelial surface and trans-corneal penetration and corneal adsorbance measured at fixed time points. To demonstrate that leakage did not occur, we applied dextran blue, which should not penetrate the intact cornea and did not do so in our model. Fluorescein penetration (0.09%) was less than rhodamine B (6.98%) at 60 min. siCASP2 penetration was 0.01% by 60 min. When the applied siCASP2 was washed off after 2 min, (representing lacrimal drainage) 0.071% penetrated porcine cornea by 60 min and 0.0002% penetrated human cornea and 0.001% penetrated human sclera. Our ex vivo model rapidly and cost-effectively assesses transcorneal penetration of candidate topical therapies, allowing rates of trans-corneal penetration for potential therapies such as siRNA to be evaluated with small quantities of human or animal tissue.
| S-EPMC7366725 | biostudies-literature