Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
|
What attaches the posterior lens surface to the anterior vitreous face?
|
The Hyaloid Capsular Ligament which is a circular ring adhesion.
|
|
|
What is the name of the space inside the ring of the hyaloid capsular ligament?
|
The retrolental space of berger which is an area of non adhesion b/w vitreous and lens.
|
|
|
What surface of the biconvex lens is the steepest?
|
The posterior surface of the lens is the steepest.
|
|
|
What is the diameter of an adult lens?
|
9mm reached at teenage years and it does'nt change much after that, an infants lens is 6.5mm
|
|
|
What is the refractive power of the unaccommodated lens? What is the maximum accommodative amplitude?
|
The unaccommodated lens is 20D and the maximum amp is 14D reached b/w 8 to 12 years of age approaching 0 after age 50.
|
|
|
What is the 1st lens like structure observable during embryologic development?
|
The Lens Vesicle
|
|
|
What are the primary lens fibers made up of?
|
Posterior epithelial cells.
|
|
|
What part of the lens capsule thickens with age?
|
The anterior lens capsule
|
|
|
What is the location of cell mitosis in the lens? What are all fibers formed in this area called?
|
The germinal zone which located in the pre-equatorial region anterior to the equator.
These fibers are called secondary lens fibers. |
|
|
What is the name for the area where nutrients and ions are exchanged in the lens throught pinocytosis?
|
The epithelium-fiber interface (EFI)
|
|
|
What are the 4 divisions of the lens?
|
Embryonic Nucleus: Made up of posterior epithelium - primary lens fibers. Also this area has the highest index of refraction.
Fetal Nucleus: fibers laid down before birth around the embryonic nucleus. Adult Nucleus: contain fibers formed b/w birth and sexual maturation Lens Cortex: Contains fibers formed after sexual maturation. The cortex has the lowest index of refraction. |
|
|
What attaches the lens to the ciliary body and where do they come from?
|
The Zonules of Zinn or the suspensory ligaments are what attaches the lens. These fibers come from the nonpigmented epithelial of the CB. The are highly elastic but contain NO true elastic fibers.
|
|
|
What happens to the lens during accommodation?
|
The ciliary muscle contracts reducing the tension on the lens. This causes the lens to bulge anteriorly increasing the curvature and hence increasing the dioptric power of the lens.
|
|
|
What is the name of the reducing agent that protects the lens from UV induced damage?
|
Glutathione detoxifies free radicals preventing damage. It is synthesized and regenerated in the cortex.
|
