Acanthamoeba Keratitis: Infection of the cornea by an ameboid protozoan which may cause corneal ulceration leading to blindness.Acanthamoeba: A genus of free-living soil amoebae that produces no flagellate stage. Its organisms are pathogens for several infections in humans and have been found in the eye, bone, brain, and respiratory tract.Keratitis: Inflammation of the cornea.Acanthamoeba castellanii: A species of free-living soil amoebae in the family Acanthamoebidae. It can cause ENCEPHALITIS and KERATITIS in humans.Contact Lenses: Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)Amebicides: Agents which are destructive to amebae, especially the parasitic species causing AMEBIASIS in man and animal.Amebiasis: Infection with any of various amebae. It is an asymptomatic carrier state in most individuals, but diseases ranging from chronic, mild diarrhea to fulminant dysentery may occur.Contact Lens Solutions: Sterile solutions used to clean and disinfect contact lenses.Contact Lenses, Hydrophilic: Soft, supple contact lenses made of plastic polymers which interact readily with water molecules. Many types are available, including continuous and extended-wear versions, which are gas-permeable and easily sterilized.Corneal Ulcer: Loss of epithelial tissue from the surface of the cornea due to progressive erosion and necrosis of the tissue; usually caused by bacterial, fungal, or viral infection.Cornea: The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)BiguanidesAmoeba: A genus of ameboid protozoa. Characteristics include a vesicular nucleus and the formation of several lodopodia, one of which is dominant at a given time. Reproduction occurs asexually by binary fission.Benzamidines: Amidines substituted with a benzene group. Benzamidine and its derivatives are known as peptidase inhibitors.Keratoplasty, Penetrating: Partial or total replacement of all layers of a central portion of the cornea.Eye Infections, Parasitic: Mild to severe infections of the eye and its adjacent structures (adnexa) by adult or larval protozoan or metazoan parasites.RNA, Ribosomal, 18S: Constituent of the 40S subunit of eukaryotic ribosomes. 18S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.Keratitis, Herpetic: A superficial, epithelial Herpesvirus hominis infection of the cornea, characterized by the presence of small vesicles which may break down and coalesce to form dendritic ulcers (KERATITIS, DENDRITIC). (Dictionary of Visual Science, 3d ed)Keratitis, Dendritic: A form of herpetic keratitis characterized by the formation of small vesicles which break down and coalesce to form recurring dendritic ulcers, characteristically irregular, linear, branching, and ending in knoblike extremities. (Dictionary of Visual Science, 3d ed)Eye Infections, Fungal: Infection by a variety of fungi, usually through four possible mechanisms: superficial infection producing conjunctivitis, keratitis, or lacrimal obstruction; extension of infection from neighboring structures - skin, paranasal sinuses, nasopharynx; direct introduction during surgery or accidental penetrating trauma; or via the blood or lymphatic routes in patients with underlying mycoses.Antiprotozoal Agents: Substances that are destructive to protozoans.Eye Infections, Bacterial: Infections in the inner or external eye caused by microorganisms belonging to several families of bacteria. Some of the more common genera found are Haemophilus, Neisseria, Staphylococcus, Streptococcus, and Chlamydia.Contact Lenses, Extended-Wear: Hydrophilic contact lenses worn for an extended period or permanently.Methylmannosides: Mannosides formed by the reaction of the hydroxyl group on the anomeric carbon atom of mannose with methyl alcohol. They include both alpha- and beta-methylmannosides.DNA, Protozoan: Deoxyribonucleic acid that makes up the genetic material of protozoa.Disinfectants: Substances used on inanimate objects that destroy harmful microorganisms or inhibit their activity. Disinfectants are classed as complete, destroying SPORES as well as vegetative forms of microorganisms, or incomplete, destroying only vegetative forms of the organisms. They are distinguished from ANTISEPTICS, which are local anti-infective agents used on humans and other animals. (From Hawley's Condensed Chemical Dictionary, 11th ed)Epithelium, Corneal: Stratified squamous epithelium that covers the outer surface of the CORNEA. It is smooth and contains many free nerve endings.Chlorhexidine: A disinfectant and topical anti-infective agent used also as mouthwash to prevent oral plaque.Clodronic Acid: A diphosphonate which affects calcium metabolism. It inhibits bone resorption and soft tissue calcification.Hygiene: The science dealing with the establishment and maintenance of health in the individual and the group. It includes the conditions and practices conducive to health. (Webster, 3d ed)Cricetulus: A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.Conjunctiva: The mucous membrane that covers the posterior surface of the eyelids and the anterior pericorneal surface of the eyeball.Mannose: A hexose or fermentable monosaccharide and isomer of glucose from manna, the ash Fraxinus ornus and related plants. (From Grant & Hackh's Chemical Dictionary, 5th ed & Random House Unabridged Dictionary, 2d ed)Eye Infections: Infection, moderate to severe, caused by bacteria, fungi, or viruses, which occurs either on the external surface of the eye or intraocularly with probable inflammation, visual impairment, or blindness.