Work

3D Auto Fluorescent Analysis of the Human Cornea

Year: 2023

Type: article

Abstract: The health of the human cornea is obligatory for optimal visual performance. It is however susceptible to a number of diseases and traumas that can impair the lucidity of this structure. For example, keratitis can result from an infection or inflammation and more than 20 diseases are known to result in corneal dystrophies. Abnormalities of the shape can result in focusing issues. The inner cell layer of the cornea may have abnormalities such as Fuchs’ dystrophy. Eye infections can scar the cornea. Eye infections such as herpes simplex virus can cause cataracts [5] and this viral infection complicates surgical treatment of the cornea as well [6]. HIV infection has now been associated with cataract formation. It is not surprising then that worldwide cataracts are a major cause of visual impairment. In fact, cataracts are also a cause of major visual impairment in the United States [1]. Moreover, epidemiological studies have demonstrated that cataracts are a Health Care Disparity in the US across groups. Cataracts are a major cause of legal blindness in African Americans [1]. Cataracts are also frequently found in the elderly [2]. Cataracts have now become a significant comorbidity in HIV infected patients. [3, 4]. The precise mechanism of cataract formation is unknown in most cases. Interestingly, cataract formation has been demonstrated in a model of HIV infection, the HIV-1 TG rat [7]. This underscores the role that HIV proteins may play in cataract formation in the HIV infected. Yet the mechanism remains unclear for all these conditions. New techniques to analyze the histology of the cornea would be helpful in investigating the above noted pathologies. The cornea may be thin, but it is histologically complex with many fine structural components. The cornea layers from anterior to posterior include: corneal epithelium, anterior limiting lamina (Bowman's layer), substantia propria (stroma), posterior limiting lamina (Descemet's membrane) and endothelium. These areas are avascular, with many fine nerve endings. Some cell types have fine processes such as the Langerhans cells, melanocytes and limbal stem cells. In view of this we used the Leica LASX Navigator Thundered imaging system to depict the fine structural details of the cornea. In this approach we produced high resolution 2D images obtained from the Z stack collections and produced 3D images demonstrating the interrelation of the different cell types in these layers. Prepared slides of cornea were obtained from Carolina supplies. These slides were stained with H&E. Imaging technique includes Wide field Fluorescence Images which acquired the images. Whole section scanning used the LASX Navigator/Thundered images (LVCC). The best focused image plane was extracted from Z-stack. A 20x Air Objective was used together with the imagining software of the Leica. The auto fluorescence of the images under green and blue light permitted the production of high-quality 3-D images of corneal architecture. The obtained images present with a high degree of resolution permitting the identification of cells and their processes both in 3D and 2D format. Examples of the corneal epithelium clearly show the layers and the fine cells process [8]. Anterior to posterior: Corneal epithelium, anterior limiting lamina (Bowman's layer), substantia propria (stroma), posterior limiting lamina (Descemet's membrane) and endothelium. Anterior to posterior Superficial Epithelial cells: SEC. Superbasal Epithelia: SBE, Basal Epithelia: BE, Bowman's Layer: BL, Limbal stem cells, Keratocytes: K. A 3D rendering was made of the cornea and will be presented at the poster session.

Source: Microscopy and Microanalysis

DOI: 10.1093/micmic/ozad067.1094