Background: Disruption of the microstructure in corneal stroma can lead to the loss of transparency. The lack of a characterization method for the microstructure prevents such scaffolds to be implemented in tissue transplantation. The non-invasive, three-dimensional (3D) rendering multiphoton microscopy (MPM) poses the potential to solve this problem.
Methods: MPM images and data analyses were performed with three kinds of samples with known and different quality. Isosurfaces (ISOs) were constructed for the evaluation of void volume and collagen distribution.
Results: The differences in the microstructures of these samples were revealed with clear indications and links to their behaviours in rehydration and possible transparency. According to this analysis, the scaffold with the highest void space ratio amongst the three presented the highest successful rates to be thoroughly rehydrated.
Conclusions: Such a method can be developed for assessing the quality of tissue engineered corneas, or donated corneas, and be useful as a powerful research tool in cornea related research.
Abstract: Corneal blindness represents one of the world’s three major causes of blindness, and the fundamental problem of corneal transplantation is a severe shortage of donor tissues worldwide, resulting in approximately 1.5 million new cases of blindness annually. To address the growing need for corneal transplants two main approaches are being pursued: allogenic and bioengineering cornea. Bioengineering corneas are constructed by naturally generating an extracellular matrix (ECM) component as the scaffold structure with or without corneal cells. It is well established that the scaffold structure directs the fate of cells, therefore, the fabrication of the correct scaffold structure components could produce an ideal corneal substitute, able to mimic the native corneal function. Another key factor in the construction of tissue engineering cornea is seed cells. However, unlike the epithelium and stroma cells, human cornea endothelium cells (HCECs) are notorious for having a limited proliferative capacity in vivo because of the mitotic block at the G1 phase of the cell cycle due to “contact-inhibition”. This review will focus on the main concepts of recent progress towards the scaffold and seed cells, especially endothelial cells for bioengineering cornea, along with future perspectives.
Abstract: Since the 21st century, the development of corneal tissue engineering technology has been developing rapidly. With the progress of biomaterials, cell culture and tissue engineering technology, tissue engineering cornea has gained great development in both basic scientific research and clinical application. In particular, tissue engineered corneal scaffolds are the core components of tissue engineered corneas. It is the focus of current research on tissue engineering cornea to search for scaffolds with good biocompatibility, high safety and good biomechanical properties. In this paper, the recent research progress of tissue engineering corneal materials is reviewed.
Abstract: Cornea serves as the partial front barrier and major light reflection organ of the eye. The integrity of corneal surface is essential for ocular function. Injuries or congenital diseases could significantly destruct the homeostasis of the ocular surface, especially the microenvironment of limbal epithelial stem cells (LESCs), and will eventually cause dysfunction of corneal regeneration and diminish of LESCs. The loss of LESCs by different reasons are named limbal stem cell deficiency (LSCD), which is one of the leading cause of vision loss worldwide. To restore the corneal surface, LESC transplantation in the form of tissue or cell cultures is currently a viable and promising method to treat LSCD. In this review, we aim to introduce the characters and niche of LESCs, and discuss different aspects of its application in cornea surface reconstruction.
Abstract: In this review, recent studies regarding riboflavin-ultraviolet A (UVA) collagen cross-linking for the treatment of acanthamoeba keratitis (AK) were reviewed. English written studies about acanthamoeba, keratitis, riboflavin and collagen cross-linking were retrieved from PubMed search engine (
www.ncbi.nlm.nih.gov/pubmed ). Although there were significant numbers of cases reporting the effectiveness of riboflavin-UVA collagen cross-linking in AK, experimental studies (in vivo and in vitro) failed to verify amoebicidal or cysticidal effect of riboflavin-UVA collagen cross-linking. In conclusion, the efficacy of riboflavin-UVA collagen cross-linking for the treatment of AK is still debatable. It is necessary to conduct a prospective case-control study for clear guidance for clinicians.
Abstract: Acute retinal necrosis (ARN) is a devastating syndrome characterized by panuveitis, retinal necrosis, and a high rate of retinal detachment that may result in poor visual outcomes if not promptly diagnosed and treated. ARN is most commonly caused by viruses within the herpesvirus family. Etiologies include varicella-zoster virus, herpes simplex virus, and cytomegalovirus, and may be promptly diagnosed by polymerase chain reaction testing of aqueous or vitreous fluid. The true incidence of ARN is not known due to its rarity; as a result, clinical treatment is often guided by retrospective case series, case reports, and expert opinion. Standard of care has evolved over time but currently includes a combination of systemic and intravitreal antiviral in conjunction with topical or oral steroids and surgical therapy as needed. Combination therapy may reduce the rate of severe vision loss and increase the rate of visual acuity gain, although further studies are needed in this area. In particular for patients with mild to moderate disease, combination therapy may reduce the rate of retinal detachment. Adjunctive therapies including oral corticosteroid and prophylactic laser barricade are incompletely studied, but corticosteroid in particular, may reduce inflammation, which also is involved in the severe disease pathogenesis observed in ARN. This review discusses the advances in diagnosis and treatment of ARN, including management with combination antiviral medication and surgical interventions.
Abstract: Cavernous hemangioma is the most primary benign orbital tumor in adults, and majority of cases could be easily settled by surgical treatment. However, cavernous hemangioma lodged deep in the orbital apex remained a challenge because the surgery may pose a high risk of injury to the optic nerve and significant visual loss. This presentation would report a case of cavernous hemangioma located in orbital apex who presented superonasal and inferotemporal peripheral vision defect. The patient received fully transnasal endoscopic surgery, and a 2 cm × 1.5 cm tumor was successfully removed from the left orbital apex. The treatment results were satisfactory, with no after-effects and adverse reactions during follow-up. This case highlighted that transnasal endoscopic surgery is a promising technique for cavernous hemangiomas that are located deep in orbital apex. This approach provides direct pathway to tumor with limiting morbidity, maximal surgical field and ample illumination. The procedure represents a safe and less invasive management.
Abstract: Vogt-Koyanagi-Harada syndrome (VKH) is a bilateral granulomatous panuveitis associated with serous retinal detachments and vitritis, and can be associated with extraocular manifestations of meningismus, poliosis, vitiligo, hearing loss, and headaches. It is mediated by CD4+ T cells that target melanocytes in the eye, ear, meninges, and skin. It classically presents in 4 different phases: prodromal, uveitic, convalescent, and recurrent. There have been considerable advances in our understanding of the disease in recent years, and options for treatment have also expanded beyond systemic corticosteroids though these remain the mainstay of therapy in patients with VKH. This brief review will focus on updates in the diagnosis and treatment of VKH, specifically advances in imaging techniques including the use of optical coherence tomography angiography (OCTA) and enhanced depth imaging (EDI) optical coherence tomography (OCT). OCT parameters that are diagnostically predictive of acute VKH compared to other exudative maculopathies include the presence of subretinal membranous structures, a high retinal detachment, subretinal hyperreflective dots, and RPE folds. Evaluations of choroidal thickness using EDI-OCT demonstrate predominant involvement of the outer choroid in the acute inflammatory phase of VKH, consistent with histopathological analysis. OCTA may emerge as an alternative to fluorescein angiography (FA) and indocyanine angiography (ICGA) but is limited at this time due to its small field of view. While the mainstay of treatment of acute VKH continues to be systemic corticosteroids, biological response modifiers (BRMs) such as adalimumab and infliximab have been shown to be effective in the management of adult and pediatric VKH with one benefit being a faster onset of action compared to conventional immunosuppression. Literature Search: A literature search was done in PubMed using the words “Vogt Koyanagi Harada” “imaging” “diagnosis” “treatment” “therapy “posterior uveitis”.
