Iris Diseases
Diseases, dysfunctions, or disorders of or located in the iris.
Iridocorneal Endothelial Syndrome
A grouping of three closely linked conditions: iris nevus (or Cogan-Reese) syndrome, Chandler Syndrome, and essential (progressive) iris atrophy. The most common features of this syndrome are the movement of endothelial cells off the cornea onto the iris leading to corneal swelling, distortion of the iris, and variable degrees of distortion of the pupil. The abnormal cell movement plugs fluid outflow channels of the eye causing GLAUCOMA.
Corneal Diseases
Diseases of the cornea.
Descemet Membrane
A layer of the cornea. It is the basal lamina of the CORNEAL ENDOTHELIUM (from which it is secreted) separating it from the CORNEAL STROMA. It is a homogeneous structure composed of fine collagenous filaments, and slowly increases in thickness with age.
Endothelium, Corneal
Single layer of large flattened cells covering the surface of the cornea.
Gonioscopy
Examination of the angle of the anterior chamber of the eye with a specialized optical instrument (gonioscope) or a contact prism lens.
Iris
The most anterior portion of the uveal layer, separating the anterior chamber from the posterior. It consists of two layers - the stroma and the pigmented epithelium. Color of the iris depends on the amount of melanin in the stroma on reflection from the pigmented epithelium.
Microscopy, Acoustic
A scientific tool based on ULTRASONOGRAPHY and used not only for the observation of microstructure in metalwork but also in living tissue. In biomedical application, the acoustic propagation speed in normal and abnormal tissues can be quantified to distinguish their tissue elasticity and other properties.
Anterior Eye Segment
The front third of the eyeball that includes the structures between the front surface of the cornea and the front of the VITREOUS BODY.
Glaucoma
An ocular disease, occurring in many forms, having as its primary characteristics an unstable or a sustained increase in the intraocular pressure which the eye cannot withstand without damage to its structure or impairment of its function. The consequences of the increased pressure may be manifested in a variety of symptoms, depending upon type and severity, such as excavation of the optic disk, hardness of the eyeball, corneal anesthesia, reduced visual acuity, seeing of colored halos around lights, disturbed dark adaptation, visual field defects, and headaches. (Dictionary of Visual Science, 4th ed)
Anterior Chamber
The space in the eye, filled with aqueous humor, bounded anteriorly by the cornea and a small portion of the sclera and posteriorly by a small portion of the ciliary body, the iris, and that part of the crystalline lens which presents through the pupil. (Cline et al., Dictionary of Visual Science, 4th ed, p109)
Trabecular Meshwork
A porelike structure surrounding the entire circumference of the anterior chamber through which aqueous humor circulates to the canal of Schlemm.
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)
Ciliary Body
Glaucoma, Angle-Closure
A form of glaucoma in which the intraocular pressure increases because the angle of the anterior chamber is blocked and the aqueous humor cannot drain from the anterior chamber.