Basics Flashcards
The infant globe is what % of the adult size?
80%
How often are cilia replaced? If cut? If pulled out?
3-5 months; 2 weeks, within 2 months
Voluntary eyelid closings uses what muscles?
Preseptal and orbital eyelid muscle
Subconscious blinking uses what eyelid muscle?
Pretarsal portion
Lymphatics drain the medial aspect of the eyelid where?
Submandibular and submental nodes
Which layer of the cornea is acellular?
Bowman’s layer
Where is the highest endothelial cell density?
In the periphery
Which part of the Descemet’s membrane grows as we age?
The posterior amorphous NON BANDED zone.
Radial incisions of the cornea does what?
Flattens in BOTH the meridian of the incision and 90 degrees away.
Tangential incisions of the cornea does what?
Flattens in the meridian of the incision and steepens 90 degrees away. This is called COUPLING.
For Radial incisions up to what limit in length does it have an effect until the effect reverses.
11-mm DIAMETER
How deep does a radial incision have to be to have optimum effect.
85-90%
What is an Axenfeld Loop, where is it located, and where does it branch from?
Its an intrascleral loop which forms a visible nodule over the ciliary body and branches from the long posterior ciliary nerves.
Slit illumination helps the examiner visualize what?
Opaque lesions.
Specular reflection is what type of illumination and is helpful to see what?
DIRECT. The posterior corneal surface and the endothelium.
Proximal illumination is what type of illumination and helps to see what?
INDIRECT. Highlights opacities against deeper tissue layers.
Sclerotic scatter is what type of illumination and what does it help with?
INDIRECT. Takes advantage of total internal reflection. Beam shines on the limbus and scatters off the sclera causes a faint glow to the cornea. Helps see epithelial edema and nebulae.
What does fluorescein staining of the cornea do?
Detects disruption of intercellular junctions.
What does rose bengal and lissamine green stain detect?
Evaluate abnormal epithelial cells (devitalized that have lost normal mucin surface) and ocular surface changes a/w insufficient tear film protection.
Which is more toxic - RB or LG?
Rose bengal and likely to induce reflex tearing. It is a photosensitized and has ANTIVIRAL effects.
Which has a blood vessel core: Follicules or Papillae?
Papillae
Which part of the cornea is the thinnest?
1.50 m temporal to the geographic center.
By what % increase in corneal thickness do u start to see Descement’s folds?
10%
When does epithelial edema occur when corneal thickness exceeds?
0.70mm
