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The anterior densely innervated corneal tissue determines more than 50% of the optical power reflection. The Cornea's structure is composed of six layers, from the epithelium to the endothelium, and a deficiency in one of these layers produces various illnesses that result in alterations in the tissue's physical and chemical characteristics. One of the mane problems happened to eye cornea is found during Keratoconus (KC), where the Cornea shape changes from normal aspherical to the cone-like protrusion of the central Cornea. This affected tissue suffers from decreased vision due to myopia, irregular astigmatism, and corneal scarring. A comprehensive review was done to investigate the Physical, chemical Properties and Clinical Diagnosis Modalities in the current work for patients with Keratoconu. Physically, where the Cornea is irregular in shape, incoming light rays cannot be focused on a single point, causing the wavefront's typical spherical shape to change. In addition, the chemical structure of basal epithelial cells influences their shape and arrangement. At the same time, a break in Bowman's layer, which is common in keratoconus, may be responsible for the conical shape of the eye. Various technologies such as keratometry, Slit lamp, Ultrasound Pachymetry, and corneal topography/tomography have been used for diagnosing KC corneas. Each of them provides essential parameters and indicates the Cornea's state. Nowadays, corneal topography techniques allow for identifying the major morphological features of diseased tissue. Furthermore, early detection of KC is critical for avoiding ocular refractive surgery, but there are no standardized screening criteria for early diagnosis. [ABSTRACT FROM AUTHOR]

With advancements in technology, it is now possible to explore the characteristics of a cornea in depth. A computer-aided diagnostic tool known as corneal topography can create a 3D map of the cornea and its surface curvature. The cornea contributes around 70% of the focusing power of an eye. It is known that evenly rounded corneas are found in eyes with normal vision. However, in cases where the eye cornea is either unevenly curved, is too steep or is too flat, it may result in vision issues. Corneal topography is a non-invasive, experimental method for assessing the cornea's morphology in qualitative and quantitative terms. Corneal topography is a visual representation of the structure and strength of the cornea. The technique can measure anterior and posterior corneal layers in three dimensions. In this research review, a review of the devices used to examine the cornea will be presented, what is extracted from each device, the working theories of each device, the general specifications extracted from the results and the outputs of each device [ABSTRACT FROM AUTHOR]

In vivo ocular temperatures in rabbits were measured during 40 GHz millimeter-wave exposure (400–100 mW/cm2). To visualize aqueous humor convection, 0.2% microencapsulated thermochromic liquid crystals (MTLCs) were injected into the anterior chambers of rabbit eyes. Exposure to 40 GHz increased corneal, lens and retrobulbar temperature, with aqueous humor convection having an important role in heat transfer from the cornea to the lens. These findings show that dynamic changes in temperature and distribution in the anterior chamber occur in living rabbit eyes during exposure to 40 GHz millimeter-waves. [ABSTRACT FROM PUBLISHER]

Femtosecond laser (FSL) is an infrared laser with a wavelength of 1053 nm. FS laser works producing photodisruption or photoionization of the optically transparent tissue such as cornea. Currently FS lasers have a wide range of applications in ophthalmic surgery. They are used above all in corneal surgery in refractive procedures and keratoplasty, and recently in cataract surgery. The use of the FSL in corneal refractive surgery includes LASIK flap creation, astigmatic keratotomy, Femtosecond Lenticule Extraction (FLEx), Small Incision Lenticule Extraction (SMILE) and channels creation for implantation of the intrastromal corneal rings. As to the corneal grafting, the FS lasers are used in laser-assisted anterior and posterior lamellar keratoplasty and customized trephination in the penetrating keratoplasty. FS Laser Assisted Cataract Surgery (FLACS) includes capsulorrhexis and nuclear fragmentation that enhance safety and efficacy of the procedure. [ABSTRACT FROM AUTHOR]

Descemet membrane detachment (DMD) develops in the human eye once the aqueous humour (AH) enters the Descemet membrane (DM) space through a break and causes the membrane to separate from the stroma (the main layer of the cornea which is responsible in giving the cornea its strength). A mathematical model of AH flow through the DMD has been developed. The mathematical model is set up to analyze the fluid mechanics concerning the progression of DMD. This model is based on the Naiver-Stokes equations that govern the flow of AH in the anterior chamber (AC). Specifically, fluid flow in the AC is described as a flow driven by buoyancy effects due to the existing temperature different between the cornea and the pupil. A thin flap (DMD) which is kept in contact with a dome shape (cornea) is considered in the flow in order to show how the type of the DMD affect the fluid flow behave in the AC. The relevant fluid flow equations have been solved numerically using finite element method with the aiding of COMSOL Multiphysics. The results have shown that the different type of DMD do affect the characteristics of the fluid flow in the AC. [ABSTRACT FROM AUTHOR]