Pseudomonas aeruginosa
Dongyou Liu in Laboratory Models for Foodborne Infections, 2017
Keratitis is a disease of the cornea that can be due to the infection with various microbes, including bacteria.42 The characteristics of bacterial keratitis include inflammation with concomitant pain and redness.42P. aeruginosa is a common cause of bacterial keratitis in humans,42 but it can also infect the cornea of other mammals including mice, rabbits, and guinea pigs. For example, the guinea pig is a model for evaluating not only antimicrobial drugs, identifying treatments,43–48 and studying the pathogenesis of P. aeruginosa keratitis but also host defense.49–51 Rabbits, on the other hand, have large eyes similar in size to those of humans and can be used to evaluate several parameters of the disease.42 The strain most commonly used to model bacterial keratitis and the efficacy of multiple treatments against P. aeruginosa is the New Zealand white rabbit.42,52–59 For example, Chen et al. demonstrated in two separate studies that lithium chloride (LiCl) and β-catenin promote host resistance against P. aeruginosa keratitis by reducing the inflammatory responses of the host and by decreasing the bacterial burden.60,61
Rubella Virus Infections
Sunit K. Singh, Daniel Růžek in Neuroviral Infections, 2013
The typical cataracts and pigmentary retinopathy seen in CRS were described by Gregg in 1941. The cataracts may consist of a central dense pearly white opacity (Figure 17.5e) or may be total with a more uniform density throughout the lens. Bilateral cataracts are found in about 50% of affected infants; they are usually present at birth but may not be visible until several weeks later. Cataracts, which are often accompanied by microphthalmia (Figure 17.6 a,b), are a useful marker for surveillance of CRS (Bloom et al. 2005; WHO 1999; Vijayalakshmi et al. 2007). Retinopathy is found in about 50% of affected infants. Hyperpigmented and hypopigmented areas of the retina give it a “salt and pepper” appearance, which can be a useful diagnostic indicator of CRS; however, because it does not cause any visual defects, it may not be suspected. Retinopathy is due to a defect in pigmentation and usually involves the macular areas. Glaucoma is less frequently observed than cataract. Other symptoms are pupil rigidity, cloudy cornea, corneal opacity, microcornea, iris hypoplasia, optic atrophy, anophthalmos, chronic uveitis, corneal hydrops, choroidal neovascularization, and keratoconus (Arnold et al. 1994; Vijayalakshmi et al. 2007). Some of these ocular abnormalities may occur later in life (see below).
Nutrition
Jan de Boer, Marcel Dubouloz in 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.
Novel Cytokine Multiplex Assay for Tear Fluid Analysis in Sjogren’s Syndrome
Published in Ocular Immunology and Inflammation, 2021
Bernd Willems, Louis Tong, Tue Dang Thi Minh, Ngoc Dong Pham, Xuan Hiep Nguyen, Markus Zumbansen
The autoimmune disease Sjögren’s syndrome (SS) induces a relatively severe form of dry eye syndrome (DES), also called keratoconjunctivitis sicca (KCS). It is characterized by a lack of tear secretion or tear instability, as well as an increase in inflammation in the tear fluid and peri-ocular glands such as the lacrimal glands, meibomian glands and the conjunctival mucosa including the goblet cells. The SS affects 0.3–0.5% of the adult western population.1,2 Women are nine times more likely to be affected than men1. When cells of the patient´s immune system wrongly recognize lacrimal and salivary gland cells as foreign entities, the resulting chronic inflammation leads to gland dysfunction which results not only in dry eyes but also dry mouth and dryness of skin. There could be various degrees of ocular manifestations ranging from eye irritation and redness to chronic inflammation and scarring of the cornea.3–5
Drugs of abuse and ocular effects
Published in Clinical and Experimental Optometry, 2021
Valérie Proulx, Benoit Tousignant
There are also commonly reported associations between the use of cocaine and corneal problems. This drug is known for its anaesthetic effect on the cornea, which can lead to decreased blinking and toxic effects to the corneal epithelium, from devitalisation of the corneal nerves or decreased epithelial integrity. Cocaine fumes or smoke may cause increased pruritus of the eye and lead to mechanical corneal trauma. When this condition is related to smoking crack cocaine, it is sometimes reported as ‘crack eye syndrome’.39,40 One study shows that after ten years of stopping cocaine, corneal nerves may still show abnormalities.41 All these effects on the cornea may lead to commonly reported conditions such as decreased corneal nerve sensitivity, microbial or fungal keratitis (with or without severe corneal ulceration), chronic dry eye from reduced tear production.39–47 There are also recurrent reports of neurotrophic keratopathy and a case of corneal perforation leading to anterior staphyloma.48
Disparities in Access to Corneal Tissue in the Developing World
Published in Seminars in Ophthalmology, 2023
Catherine Liu, Hajirah N. Saeed
Corneal disease is a major cause of blindness worldwide, currently ranking fourth after cataract, glaucoma, and age-related macular degeneration.1 In 2020, 43.3 million people were estimated to be blind using the World Health Organization’s (WHO) definition of blindness as best corrected vision worse than 3/60 (20/400) in the better seeing eye.1,2 Of these, 4.2 million cases of blindness were attributable to corneal opacity and an additional 2 million cases are secondary to trachoma.1 In developing countries, corneal disease may represent the second leading cause of blindness,3 which is disproportionately higher than in other countries. In certain regions of Africa, as much as 90% of all blindness is attributable to corneal pathology4; however, availability and access to cornea tissue, which can often cure corneal blindness, in these parts of the world is dismal compared to industrialized countries. In contrast, the US has the highest rate of corneal transplantation, with the greatest amount of corneal procurement and transplantation per capita worldwide.5 There exists a significant disparity between countries when it comes to access to cornea tissue, with supply often inversely proportional to burden of disease.6 There are many variables and challenges that perpetuate this disparity. This review will discuss those factors as well as highlight how reduction in corneal blindness and access to sight saving cornea tissue may be attainable.
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