What is palisade 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).
Where is the limbus of the eye?
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 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.
What is the definition for Palisades?
1a : a fence of stakes especially for defense. b : a long strong stake pointed at the top and set close with others as a defense. 2 : a line of bold cliffs. palisade.
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.
Why is the cornea transparent?
Its transparency is a result of the homogeneity of the refractive index of all its constituent cells (Dohlman, 1971). However, it should be noted that in a number of corneal pathologies, changes in one or more of the other layers can lead to increased light scattering and consequent loss of corneal transparency.
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.
How were the Palisades formed?
In the case of the Palisades, the magma cooled under the sedimentary layers, forming a sill made of igneous diabase about 40 miles long and 1,000 feet thick. During this time, crustal movements along the Ramapo fault tilted the entire region downward about 17 degrees to the west.