The scleral spur in the

visual system The visual system is the physiological basis of visual perception (the ability to perception, detect and process light). The system detects, phototransduction, transduces and interprets information concerning light within the visible range to ...

is a protrusion of the

sclera The sclera, also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective outer layer of the eye containing mainly collagen and some crucial elastic fiber. In the development of t ...

(the white of the eye) into the

anterior chamber The anterior chamber ( AC) is the aqueous humor-filled space inside the eye between the iris and the cornea's innermost surface, the endothelium. Hyphema, anterior uveitis and glaucoma are three main pathologies in this area. In hyphema, ...

. The spur is an annular structure composed of collagen in the

human eye The human eye is a sensory organ in the visual system that reacts to light, visible light allowing eyesight. Other functions include maintaining the circadian rhythm, and Balance (ability), keeping balance. The eye can be considered as a living ...

. It is the origin of the longitudinal and circular fibres (which swerve acutely from the spur to run circumferentially, as a sphincter near the periphery of the

lens A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements'') ...

) of the

ciliary muscle The ciliary muscle is an intrinsic muscle of the eye formed as a ring of smooth muscleSchachar, Ronald A. (2012). "Anatomy and Physiology." (Chapter 4) . in the eye's middle layer, the uvea ( vascular layer). It controls accommodation for vie ...

, and is attached posteriorly to the

trabecular meshwork The trabecular meshwork is an area of tissue in the eye located around the base of the cornea, near the ciliary body, and is responsible for draining the aqueous humor from the eye via the anterior chamber (the chamber on the front of the ...

Role in treatment of Glaucoma

Open-angle

glaucoma Glaucoma is a group of eye diseases that can lead to damage of the optic nerve. The optic nerve transmits visual information from the eye to the brain. Glaucoma may cause vision loss if left untreated. It has been called the "silent thief of ...

(OAG) and closed-angle glaucoma (CAG) may be treated by muscarinic receptor

agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...

s (e.g.,

pilocarpine Pilocarpine, sold under the brand name Pilopine HS among others, is a lactone alkaloid originally extracted from plants of the Pilocarpus genus. It is used as a medication to reduce pressure inside the eye and treat dry mouth. As an eye drop ...

), which cause rapid

miosis Miosis, or myosis (), is excessive constriction of the pupil.Farlex medical dictionary
citing: ...

and contraction of the ciliary muscles, this pulls the scleral spur and results in the trabecular meshwork being stretched and separated. This opens the fluid pathways, and facilitates drainage of the aqueous humour, into the canal of Schlemm and ultimately results in decreasing of the

intraocular pressure Intraocular pressure (IOP) is the fluid pressure inside the eye. Tonometry is the method eye care professionals use to determine this. IOP is an important aspect in the evaluation of patients at risk of glaucoma. Most tonometers are calibrated t ...

.Neal, M. J. (2004). "Medical Pharmacology at a Glance" (6th edition). Wiley-Blackwell. p. 27.

Additional images

File:Anterior chamber angle - 3D motion parallax.gif,

Gonioscopy In ophthalmology, gonioscopy is a routine procedure that measures the angle between the iris (anatomy), iris and the cornea (the iridocorneal angle), using a goniolens (also known as a gonioscope) together with a slit lamp or operating microscope ...

of the anterior chamber angle File:Kammerwinkel.jpg,

of the anterior chamber angle. Labeled structures: 1.

Schwalbe's line Schwalbe's line is the anatomical line found on the interior surface of the eye's cornea, and delineates the outer limit of the corneal endothelium layer. Specifically, it represents the termination of Descemet's membrane. In many cases it can b ...

, 2.

Trabecular meshwork The trabecular meshwork is an area of tissue in the eye located around the base of the cornea, near the ciliary body, and is responsible for draining the aqueous humor from the eye via the anterior chamber (the chamber on the front of the ...

(TM), 3. Scleral spur, 4.

Ciliary body The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor. The aqueous humor is produced in the non-pigmented portion of the ciliary ...

, 5. Iris File:SD OCT - Anterior Chamber Angle Cross-Section (with viewfinder).png, Anterior chamber angle cross-section imaged by an SD-OCT.

References

{{DEFAULTSORT:Scleral Spur Human eye anatomy

Role in treatment of Glaucoma

Additional images

See also

References