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The Host Response to Grafts and Transplantation Immunology
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Some tissues, such as corneas, are poorly vascularized, and have little contact with the immune system; also there are few technical complications with corneal transplants. For these reasons, corneal transplants are highly successful.
Maroteaux-Lamy disease/mucopolysaccharidosis VI/N-acetylgalactosamine-4-sulfatase deficiency
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
The corneas develop opacities at an early stage that are detectable by slit lamp examination and progressively become clinically cloudy. This is especially dense at the periphery, and it may lead to visual impairment. Glaucoma was reported in four adult women [20]. Deafness is a regular feature, related at least in part to recurrent otitis media.
Nutrition
Published in Jan de Boer, Marcel Dubouloz, Handbook of Disaster Medicine, 2020
Severe vitamin A deficiency causes xerophthalmia, blindness and death. Clinical eye signs include: poor vision in dim light, dryness of conjunctiva or cornea, foamy material on the conjunctiva, or clouding of the cornea itself. These signs may appear after several months of an inadequate diet, or following acute or prolonged infections, particularly measles and diarrhoea. Mild/moderate vitamin A deficiency increases young-child mortality rates by about 20%. Clinical assessment reveals signs only in a very small proportion of subjects in populations affected by vitamin A deficiency and large numbers of children must be examined if this is the method of assessment used. Biochemical assessment is by the modified relative dose response (MRDR), which detects mild and moderate deficiency5.
What we know about the scleral profile and its impact on contact lens fitting
Published in Clinical and Experimental Optometry, 2023
Javier Rojas-Viñuela, Melanie J Frogozo, David P Piñero
The initial differences between individuals, and the asymmetric profile in different meridians of the same eye have been confirmed with the advent of these new devices. Furthermore, the Scleral Shape Study Group (SSSG) established a new classification for the scleral shape on which four different scleral profiles were defined15: (Figure 4) (1) 5.7% of scleras were spherical with differences between the lowest and highest sagittal height below 300 microns (Figure 4A); (2) 28.6% of eyes showed a scleral toric regular pattern with differences in sagittal height above 300 microns and with 180º periodicity between the lowest and the highest points (Figure 4B); (3) the largest profile group comprised 40.7% of the scleras and had elevations and depressions or a single large elevation (Figure 4C); (4) the remaining 26% were irregular, showing a toric pattern but with no 180º periodicity (Figure 4D).15 This study did not record whether the measured eyes were healthy or affected by ectasias or surgeries. However, the patients were candidate for prospective scleral lens fits. Thus, several irregular and pathological corneas could be expected among the analysed eyes.15 This is somehow relevant because some differences in the scleral profile of healthy and pathological eyes have been established.
Evaluation of corneal staining with an antihistamine-releasing contact lens
Published in Clinical and Experimental Optometry, 2023
After baseline (approximately day −4) and dispensing visits (day 0), follow-up visits occurred at approximately 1 week, 4 weeks, 8 weeks, and 12 weeks of lens wear. Assessments at every visit included slit-lamp evaluation of corneal staining in all five regions of the corneas of both eyes. To aid the assessment of corneal staining, sodium fluorescein was instilled prior to slit-lamp evaluation; investigators instilled sodium fluorescein in accordance with the standard practice of their clinic. The investigators were not instructed whether to use filters. Corneal staining was graded on a 0 to 4 scale, where 0 = no staining, 1 = trace staining, 2 = mild staining, 3 = moderate staining, and 4 = severe staining. The specific corneal staining scale, adapted from regulatory guidance,15 is displayed in Figure 1.
Beneficial Effects of Plasma Rich in Growth Factors (PRGF) Versus Autologous Serum and Topical Insulin in Ocular Surface Cells
Published in Current Eye Research, 2023
Eduardo Anitua, María de la Fuente, Ronald M. Sánchez-Ávila, Borja de la Sen-Corcuera, Jesús Merayo-Lloves, Francisco Muruzábal
Corneal disorders include a wide variety of pathologies, such as persistent epithelial defects, dry eye, limbal stem cell deficiency and ulcers, among others. A mild condition of any of these diseases may only affect the corneal and conjunctival epithelia, however progression of the eye disorder to a more severe condition may reach the corneal or conjunctival stroma, affecting the subpopulation of keratocytes or conjunctival fibroblast surrounding the injury site.1 The epithelial healing process requires the coordination of several growth factors and cytokines that mediate the interactions between corneal epithelium and stroma. In addition, epithelial and stromal cells interact with each other across the basement membrane, triggering stromal responses involving apoptosis, activation, and transdifferentiation of keratocytes into myofibroblasts.2 However, the persistence of myofibroblastic cells after wound healing can lead to the haze or scar tissue formation, reducing the patient visual capacity.