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Ocular 6 > Iris Ugh > Flashcards

Iris Ugh Flashcards

1
Q

Average diameter of the iris?

A

12mm

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2
Q

How thick is the iris root?

A

500 microns (thinnest point)

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3
Q

Pupil center is what to iris center?

A

Slightly nasal and inferior

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4
Q

What are the four layers of the iris?

A
  • anterior border layer
  • stroma and sphincter muscle
  • anterior epithelium and dilator muscle
  • posterior epithelium
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5
Q

Which layer of the iris is the dilator muscle?

A

Anterior epithelium

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6
Q

Is the anterior border layer separate from the stroma?

A

Nope

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7
Q

What kind of cells are in the anterior border layer?

A

Fibroblasts and pigmented melanocytes

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8
Q

Anterior iris synechia at iris periphery can adhere to what?

A

Corneal endothelium or trabecular mesh work

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9
Q

What kind of cells does the iris stroma consist of? How are the fibrils arranged?

A
  • pigmented AND non pigmented cells!
  • collagen fibrils in radial columns
  • extensive ground substance
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10
Q

What muscle is in the stroma?q

A

Sphincter muscle

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11
Q

What does the sphincter muscle do?

A
  • joined by tight junctions to constrict for miosis
  • anchored to stroma
  • innervates by parasympathetic system
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12
Q

The end of what muscle indicates the pupillary area?

A

The end of the constrictor muscle

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13
Q

The apical portion of the anterior epithelium is made of what and which direction does it face?

A
  • pigmented epithelium with tight junctions

- faces back

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14
Q

The basal portion of anterior epithelium is composed of what? Faces what directions?

A
  • smooth muscle processes which extend into the stroma

- faces front

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15
Q

Which layer is the dilator muscle in?

A

Anterior epithelium

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16
Q

What does the dilator muscle do?

A

-cause mydriasis and is sympathetically innervates

17
Q

What kind of cells are in the posterior epithelium?

A

-single layer of heavily pigmented columnar cells joined by tight junctions

18
Q

Which epithelium layer has pigment that comes off when it rubs the lens?

A

Posterior epithelium

19
Q

Where is the major circle of the iris? Talk about the collagen too

A
  • located in the ciliary body
  • follow radial course
  • thick walled blood vessels-collagen fibrils encircling vessels are continuous with the collagen network of the stroma
20
Q

Where is the minor circle of the iris?

A
  • at the junction of ciliary and pupillary portions

- located within the iris stroma

21
Q

Which circle is non fenestrated and forms the blood aqueous barrier?

A

-mini circle of the iris

22
Q

Where is the major arterial circle of the iris located?

A

In the ciliary body

23
Q

You fire a diode laser shot at the iris and see black charring on the surface. Which layer was affected?

A

Anterior border layer

24
Q

You fire a YAG laser shot at the iris and see pigment coming out of the pupil. What layer cause this?

A

Posterior epithelium

25
Q

You fire an argon laser shot at the iris and see contraction around the spot which layer was affected?

A

Stroma

26
Q

You fire an infrared diode laser at the iris and notice radial movement from the pupil to the limbus. Which layer was this?

A

Anterior epithelium and dilator muscle

27
Q

How many times per second does the eye constrict/dilate?

A

2 times per second

28
Q

What are rhythmic oscillations called?

A

Hippus

29
Q

Increased illumination causes what effect with hippus

A

Larger and more rapid in increased illumination

30
Q

What is iridodialysis

A
  • root tears away from the ciliary body

- blood may hemorrhage into anterior or posterior chambers to create hyphema

31
Q

Iris color depends on what?

A
  • number AND type of melanin granules within the melanocytes.
  • IT DOES NOT DEPEND ON THE NUMBER OF MELANOCYTES BECAUSE THAT IS CONSTANT
32
Q

In Horner’ syndrome, which pupil has a lighter iris?

A

The smaller pupil

33
Q

What is pigmentary dispersion syndrome?

A
  • pigment shed from posterior iris surface
  • depostied on iris, lens, corneal epithelium or mesh work
  • can cause transillumination defects
34
Q

What is anisocoria

A
  • detectable difference between pupil diameters

- less than 0.4mm is normal

35
Q

Name the primary functions of the iris

A
  • regulate retinal illumination
  • regulate glare
  • regulate optical aberrations
  • regulate depth of focus
  • nonverbal communication and social signaling
  • attraction/mate selection
36
Q

What size pupil increases depth of focus?

A

Smaller

Ocular 6 (6 decks)

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