Flashcards in Exam 1 Remington- Cornea Deck (123)
What is keratoconus?
Corneal dystrophy, caused is nutritional or metabolic
What is the initial disruption in keratoconus?
BM and Bowman's
Keratoconus eventually involves what?
Significant stromal thinning
What type of astigmatism does keratoconus produce?
Irregular astigmatism, cannot be corrected with spectacles
What may slow the progression of keratoconus?
What is Munson's sign in keratoconus?
Lower lid conforms to conic shape on down gaze
Currently clinical trials are evaluating collagen cross linking to what?
Slow disease progression
What is collagen cross linking?
Riboflavin saturates the cornea and is then activated by ultraviolet light, this increase cross linking between collagen fibrils thus strengthening the cornea and may arrest the progression of keratoconus
What is the cellular composition of Descemet's membrane?
Dense CT, acellular
What is the BM of corneal endothelium?
Descemet's membrane is highly resistant to ______ ______
Descemet's membrane has ________ properties
What is the termination of Descemet's membrane in the corneal periphery?
How are the cells in the endothelium arranged?
Regular arrangement = endothelial mosaic
What % of cells are hexagonal in the endothelium?
The endothelium does not _______; cells just spread out. Cells appear to be in ______ state.
What are the 4 intercellular junctions in the endothelium?
Lateral interdigitations, gap junctions, occluding junctions, and modified hemidesmosomes
What are occluding junctions?
"Slightly leaky" barrier
What are Hassall-Henle bodies?
Thickenings in Descemet's membrane, they are a normal physiological aging change
Deposits in Descemet's membrane indicative of dysfunction
Recent studies suggest that there is this collagenous layer between stroma and Descemet's membrane
What cells are Dua's layer composed of?
Acellular and composed primarily of collagen type 1
The presence of Dua's layer might be important for what?
Current corneal transplant procedures
Are there corneal BVs?
Why are there no corneal BVs?
There may be an antiangiogenic agent present
What type of sensory innervation is in the cornea?
The cornea has about ____ times as many sensory fibers in the tissue than anywhere else in the body
How many bundles of axons enter the corneal periphery?
Fibers lose the myelin sheath within ___ mm into cornea