What is palisades of Vogt?
The palisades of Vogt are distinctive normal features of the human corneoscleral limbus. Our clinical studies indicate that they are more discrete in younger and in more heavily pigmented individuals, and that they appear more regular and prominent at the lower limbus than at the upper limbus.
What is limbal girdle of Vogt?
White limbal girdle of Vogt is a very common, bilateral, innocuous, age-related condition characterized by chalky-white, crescentic deposits (elastotic degeneration) along the nasal and temporal perilimbal cornea. It may or may not be separated from the limbus by a clear zone (Figure 6-1B).
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.
Where is the corneal limbus?
Summary 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.
What produces conjunctiva?
Function. The conjunctiva helps lubricate the eye by producing mucus and tears, although a smaller volume of tears than the lacrimal gland. It also contributes to immune surveillance and helps to prevent the entrance of microbes into the eye.
Where is limbal girdle of Vogt?
The limbal girdle of Vogt is located at 9:00 o’clock and 3:00 o’clock.
What causes Vogt’s striae?
Striae can be attributed to undulations, not ruptures, in continuous collagen lamellae of the stroma. Lamellae are 1-3 µm thick. The undulations originate at Descemet’s membrane and travel through the corneal stroma toward Bowman’s layer.
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.
Where is palpebral conjunctiva found?
eyelids
The palpebral conjunctiva lines the eyelids. The bulbar conjunctiva is found on the eyeball over the anterior sclera. Tenon’s capsule binds it to the underlying sclera.
Where is the tarsal plate?
upper eyelid
The tarsi (tarsal plates) are two comparatively thick, elongated plates of dense connective tissue, about 10 mm (0.39 in) in length for the upper eyelid and 5 mm for the lower eyelid; one is found in each eyelid, and contributes to its form and support. They are located directly above the lid margins.
Is the cornea part of the conjunctiva?
The conjunctiva is a thin membrane lining the inside of your eyelids (both upper and lower) and covering the outer portion of the sclera (white part of the eye). It doesn’t cover the cornea, which is the clear covering on the front of the eye. The area where the conjunctiva meets the cornea is called the limbus.
What is difference between conjunctiva and sclera?
The conjunctiva contributes to the tear film and protects the eye from foreign objects and infection. The sclera is the thick white sphere of dense connective tissue that encloses the eye and maintains its shape.
How to identify the Palisades of Vogt in ex vivo tissue?
Purpose: The Palisades of Vogt (POV) constitute the corneal epithelial stem cell niche, but identification of this region in ex vivo tissue is difficult. Here we introduce a simple, direct method of identifying the POV in unsectioned, ex vivo human tissue. Methods: Twenty-two eyes were studied, four whole and eighteen rims.
What are the Palisades of Vogt?
The palisades of Vogt are distinctive normal features of the human corneoscleral limbus. Our clinical studies indicate that they are more discrete in younger and in more heavily pigmented individuals, and that they appear more regular and prominent at the lower limbus than at the upper limbus.
What is the anatomy of the ear in anatomy 54?
54 Anatomy and physiology of the ear and hearing Figure 2.1. The pinna and external auditory canal form the outer ear, which is separated from the middle ear by the tympanic membrane. The middle ear houses three ossicles, the malleus, incus and stapes and is connected to the back of the nose by the Eustachian tube.
What is the outer wall of the middle ear?
The outer wall of the middle ear is the tympanic membrane, the inner wall is the cochlea. The upper limit of the middle ear forms the bone beneath the middle lobe of the brain and the floor of the middle ear covers the beginning of the great vein that drains blood from the head, the jugular bulb.