Lecture 1: 11/9 Flashcards

1
Q

list the 3 ocular axes

A
  1. geometric (anatomical)
  2. optic
  3. visual
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2
Q

geometric (anatomical) axis is

A

saggital section of the eye (right down the center)

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3
Q

optic axis is based on

A

passage and refraction of light through the eye (cornea and lens)

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4
Q

location of optic axis is

A

through the centers of the refractive elements of the eye (cornea and the lens)

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5
Q

visual axis (physiological) is

A

from the object of regard to the fovea through the nodal point of the lens

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6
Q

geometric axis is if you drew a line from

A

anterior pole to posterior pole

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7
Q

anatomical axis length for an adult is

A

24mm

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8
Q

most of the growth of the human eye takes place

A

in the first 3 years

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9
Q

growth pattern lengths for the eye at birth, 3 years, and 13 years

A

birth: 16-17mm
3 years: 22.5-23mm
13 years: 24mm

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10
Q

definition of the eye’s equator

A

a line equidistant from the anterior pole to posterior pole

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11
Q

“horizontal” and “vertical” distances of the eye are different, what are the values?

A

vertically: 23mm
horizontally: 23.5mm

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12
Q

disproportions of the eye are

A

not completely round: wider than it is tall

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13
Q

definition of the meridian

A

a line 90 degrees from the equator

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14
Q

volume of the eye

A

6.5cc

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15
Q

weight of the eye

A

7.5 gm

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16
Q

3 tunics/ layers of the eye are

A
  1. fibrous
  2. vascular
  3. retinal (neural)
17
Q

layers of the eye from outermost to innermost

A

(outermost) fibrous -> vascular -> retinal (innermost)

18
Q

the fibrous tunic is composed of what two structures?

A

cornea and sclera

19
Q

part of the fibrous tunic that is anterior and 1/6 of tunic

20
Q

part of fibrous tunic that is posterior and 5/6 of tunic

21
Q

cornea and sclera are both composed of what types of connective fibers?

A
collagen fibers 
(same fibers extend from cornea into sclera)
22
Q

vascular tunic structures (from posterior to anterior)

A

choroid, ciliary body, iris

23
Q

choroid is located ____ and consists of ____ fraction of the tunic

A

posterior and 3/4 of the tunic

24
Q

purpose of the choroid is to

A

supply nutrients and oxygen to structures exterior (sclera) and interior (retina)

25
ciliary body is the
muscular band that is involved in changing the lens focusing
26
iris is the ___ most component of the vascular tunic
anterior
27
is the iris a completely continuous part of the layer and why?
no, hole in the anterior part called the pupil
28
the purpose of the iris is to
be the diaphragm that can enlarge or reduce the pupil
29
embryology of the retina
during embryological development- retina is an out growth of the brain
30
what does the retina do?
changes light energy to a neuro-chemical signal
31
what is the most important property of the cornea
transparency
32
list of 3 factors that influence transparency of the cornea
1. regularity in stroma 2. smoothness 3. avascularity
33
in the cornea, all the collagen fibers are in a layer called the
stroma | thickest
34
fiber vs. cell arrangement in stroma
collagen fibers regular and precise arrangement | very few cells, lots of collagen fibers
35
list of 4 conditions for factors influencing transparency of cornea
1. normal metabolism 2. nutrition, oxygen 3. water, H2O 4. health of cornea
36
cornea/lens refractive element percentages
cornea 65% | lens 35%