What is the corneal limbus?

What is the corneal limbus?

The limbus forms the border between the transparent cornea and opaque sclera, contains the pathways of aqueous humour outflow, and is the site of surgical incisions for cataract and glaucoma. ... Their superficial branches form arcades to supply the limbal conjunctiva and peripheral cornea.

Is the limbus part of the conjunctiva?

The limbus does not constitute a separate tissue but, rather, the border zone or the ocular globe separating cornea, conjunctiva, sclera, and uvea.

Why are limbal stem cells important?

The microenvironment of the limbus is considered to be important in maintaining the stemness of stem cells. Limbal stem cells also act as a "barrier" to conjunctival epithelial cells and normally prevent them from migrating on to the corneal surface.

How wide is the corneal scleral limbus?

Utilising the OCT, the limbal zone has been defined to be 'between the outer edge of the visible iris and the outer corneal sulci' and using these criteria, the limbal zone has been determined to be 0.93 mm wide.

What is limbal stem cell deficiency?

Limbal stem cell deficiency (LSCD) is characterized by a loss or deficiency of the stem cells in the limbus that are vital for re-population of the corneal epithelium and to the barrier function of the limbus. When these stem cells are lost, the corneal epithelium is unable to repair and renew itself.

How wide is the limbus?

Average limbus nasal-temporal diameters were 13.64±0.55 mm for right eyes, and 13.74±0.40 mm for left eyes, however the superior-inferior diameters were 13.65±0.54 mm, 13.75±0.38 mm for right and left eyes, respectively.

What is the limbal conjunctiva?

The corneal limbus is the border between the cornea (and the conjunctiva covering it) and the sclera. It is highly vascularised. Its stratified squamous epithelium is continuous with the epithelium covering the cornea.

What impact does the limbus have when damaged?

If the stem cells at the limbus are damaged, the renewal process is interrupted. The complete or partial loss of these stem cells — limbal stem-cell deficiency (LSCD) — allows the opaque conjunctiva to grow over the cornea. This can lead to intense pain and, in the most-severe cases, blindness.

How many people have limbal stem cells?

Over 6 million people worldwide are affected by corneal blindness, and limbal stem cell deficiency is one of the main causes.

What is limbal stem cell transplant?

Limbal stem cell transplantation is a surgical treatment to address LSCD and restore a corneal epithelial phenotype. Based on the source of cells, limbal transplant can be autologous or allogenic. Many surgical techniques are defined according to the source of the stem cells and the carrier tissues that are used.

What does Limbus corneae mean?

• Limbus Corneae. An annular transitional zone, approximately 1 mm wide, between the cornea and the bulbar conjunctiva and sclera. It is highly vascular and is involved in the metabolism of the cornea. It is ophthalmologically significant in that it appears on the outer surface of the eyeball as a slight furrow, marking the line between the clear cornea and the sclera.

What causes a limbus vertebra?

• Limbus vertebrae result from an intrabody herniation of disc material. It can be mistaken for a fracture, infection or tumour.

Is the cornea a living tissue?

• Although the cornea may look clear and seem to lack substance, it is a highly organized tissue. Unlike most tissues in the body, the cornea contains no blood vessels to nourish or protect it against infection.

Where is the limbus of the eye located?

• Limbus Epithelium. Eye.LmE. The limbus epithelium is a narrow ring of tissue at the transitional zone between the corneal epithelium and conjunctiva. The limbus is characterized by the palisades of vogt (PV), an undulating network, where clusters of limbal stem cells (LSCs) are located.