Initial iris configuration was concave in all eyes with pigment dispersion syndrome, whereas in control eyes it was concave in four eyes, planar in four eyes, and convex in two eyes.
Are irises concave?
Notably, the iris had a concave configuration with significant backward bowing. Her optic nerves appeared healthy, with robust, symmetrical neuroretinal rims. Optical coherence tomography showed a normal retinal nerve fiber layer in both eyes.
Is the iris convex?
In eyes with convex-to-convex configuration, the iris was more convex in the narrow-angle group than in the open-angle group, although iris thickness was not significantly different between the groups (Table 4). The dynamic patterns of iris bowing were significantly related to age and axial length.
Is the iris flat?
The iris is a flat and ring-shaped membrane behind the cornea of the eye with an adjustable circular opening in the center called a pupil. This is the structure that provides an individual with eye color.
What causes plateau iris?
Plateau iris is caused by a narrowing of the anterior chamber angle due to insertion of the iris anteriorly on the ciliary body or displacement of the ciliary body anteriorly, which in turn alters the position of the peripheral iris in relation to the trabecular meshwork (i.e. placing them in apposition).
What is pupillary block?
Pupillary block is the most common mechanism leading to acute angle-closure glaucoma, and it occurs when the flow of aqueous humor from the posterior chamber to the anterior chamber is obstructed by a functional block between the pupillary portion of the iris and the lens.
How thick is the iris?
750 μm
The iris thickness was measured at 750 μm (IT750) and 2000 μm (IT2000) from the scleral spur (i.e., toward the pupil), as well as the cumulative cross-sectional area of the full length (from spur to pupil) of the iris (IAREA). The locations for iris thickness measurement were adjusted from the Ishikawa protocol.
What is scleral spur?
The scleral spur is a fibrous ring that, on meridional section, appears as a wedge projecting from the inner aspect of the anterior sclera (Figs 3-1 and 3-2). The spur is attached anteriorly to the trabecular meshwork and posteriorly to the sclera and the longitudinal portion of the ciliary muscle.
What is pigment dispersion?
Pigment-dispersion syndrome is an eye disorder that occurs when pigment granules that normally adhere to the back of the iris (the colored part of the eye) flake off into the clear fluid produced by the eye (aqueous humor).
What is the iris function?
The iris controls the amount of light that enters the eye by opening and closing the pupil. The iris uses muscles to change the size of the pupil. These muscles can control the amount of light entering the eye by making the pupil larger (dilated) or smaller (constricted).
Is the iris opaque?
The function of the iris is to limit the amount of light that passes through the lens to the retina. To make the iris opaque, it is coated with the pigment melanin, in varying degrees for each of us. Melanin makes the eyes dark brown and 10,000 years ago, everyone’s eyes were this colour.
What is the function of the iris quizlet?
Acts as a diaphragm regulating the amount of light entering the eye. It prevents the retina from receiving excess light by reducing spherical aberrations and improved depth perception.
What is aqueous misdirection?
Aqueous misdirection is a challenging form of secondary angle closure that presents with elevated intraocular pressure (IOP) and shallowing of the central and peripheral anterior chamber despite the presence of a peripheral iridotomy.
What is a laser iridotomy?
Laser iridotomy is a treatment for narrow-angle glaucoma. In laser iridotomy, a small hole is placed in the iris to create a hole for fluid to drain from the back of the eye to the front of the eye.
What is peripheral iridotomy?
Laser peripheral iridotomy (also described as ‘laser iridotomy’ or simply termed ‘iridotomy’) is a medical procedure which uses a laser device to create a hole in the iris, thereby allowing aqueous humor to traverse directly from the posterior to the anterior chamber and, consequently, relieve a pupillary block.
What is Pseudophakia of the eye?
Pseudophakia is a Latin word for false lens. We use this term after placing an artificial lens into the eye. Also known as intraocular IOL, lens implants, or “fake eye lenses,” this procedure can significantly improve vision after removing cataracts and replacing them with a new lens.
How do you get hyphema?
A hyphema is most often caused by blunt trauma to the eye. In children and adolescents the most common cause is from sports or recreational activities. It can also occur as a result of surgery inside the eye or an abnormality of blood vessels inside the eye.
What is non pupillary block?
A less common cause of primary angle closure is anterior non-pupillary block. This is observed in eyes in which angle closure progresses despite a patent iridotomy, for example, as seen in plateau iris.
What is ora serrata in human eye?
Peripheral Retina
The ora serrata is the peripheral termination of the retina and lies approximately 5 mm anterior to the equator of the eye. 123. Its name derives from the scalloped pattern of bays and dentate processes (see Chapter 3); the retina extends further anteriorly on the medial side of the eye.
What is a vortex vein?
The vorticose veins, referred to clinically as the vortex veins, drain the ocular choroid. The number of vortex veins is known to vary from 4 to 8 with about 65% of the normal population having 4 or 5.However, the veins run posteriorly in the sclera exiting the eye well posterior to the equator.
What is lamina Cribrosa?
The lamina cribrosa forms the bottom of the optic cup on the inner surface of the optic nerve head. On the outer surface of the optic nerve head, the posterior part of the lamina cribrosa faces the anterior region of the optic nerve.
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