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Flashcards in B10 Deck (242):
1

The pupil that is seen is actually a _____ image of the ____ pupil

Magnified virtual image of the real object pupil

2

Name the 7 functions of the iris

-improve visual clarity (regulates optical aberrations
-attraction/mate selection
-non verbal communication
-reduce glare
-control illumination
-prevent dazzling
-increase the depth of focus

3

The iris separates the

Anterior and posterior chambers of the eye

4

The iris is surrounded by what fluid?

Aqueous

5

T/f: the iris is the most anterior portion of the uveal tract

True

6

The iris rests lightly upon the ___

Lens

7

What is the average diameter of the iris?

12mm

8

The pupil center is slightly __ and ___ to the iris center

Slightly nasal and inferior

9

An abnormally decentered pupil

Ectopic

10

What does irregular or ectopic pupils do to optical quality

They degrade it

11

The pupillary margin rests on the ___ surface of the lens

Anterior

12

How does aqueous humor flow

It flows from the posterior-->anterior through the pupil

13

T/F: Temporal iris in humans broader than nasal iris

True

14

The posterior portion of the iris is derived from?

Neuroectoderm/neuroepithelium

15

The dilator muscle is derived from the

Neuroepithelium

16

The sphincter muscle is derived from the

Neuroepithelium

17

The posterior pigmented epithelium is derived from the

Neuroepithelium

18

The anterior portion of the iris is derived from

Mesoderm

19

The iris stroma is derived from

Mesoderm

20

The iris vessels is derived from

Mesoderm

21

The iris nerves are derived from

Mesoderm

22

The chromatophores are derived from

Mesoderm

23

What are the 4 layers of the iris?

-anterior border layer
-stroma and sphincter muscle
-anterior epithelium and dilator muscle
-posterior epithelium

24

What layer contains both mesoderm and ectoderm

Stroma and sphincter muscle

25

The reduction in optical aberrations and depth of focus is optimal at

2mm or less

26

What are the only elements in the iris that is capable of initiating movement

Iris muscles

27

What occurs in miosis (constriction if pupils)

the pupillary portion of iris gathers into pleats while the ciliary portion smooths out.

28

What occurs in mydriasis (dilation)

the stroma in the pupillary zone pulls flat while
contraction furrows appear in the ciliary area.

29

T/F: blow flow is impeded by wither miosis or mydriasis

False. It is not impeded

30

T/F: in the past, it was believed that the stroma and blood vessels were responsible for iris movements, via elastic expansion, changes in hydration, and/or engorgement.

True

31

T/F: the stroma and iris vessels are elastic

False. They are not elastic

32

is a loose but orderly meshwork of collagen fibers with aqueous fluid and scissor like angles for folding

Stroma

33

Thin-walled layer of endothelium with an outer
covering of collagen fibrils.

Iris vessels

34

The thickest portion of the iris

Stroma

35

What are the 4 functions of the stroma

-provides an anchor for structures
-protects the nerves and vessels from stretching and kinking
-adapts to constant movement
-folds and unfolds with minimal resistance to minimize energy expenditure

36

The stroma provides an anchor for what 4 structures?

-sphincter muscle
-dilator-posterior-epithelial plate
-iris nerve
-iris vessels

37

Structure that is more densely than deeper stroma

Anterior border layer

38

Dark brown spots that are compact masses of rounded cells filled with melanin

Nevi

39

T/F: the anterior border layer is more solid and dense with more layers in darkly pigmented eyes.

True

40

What kind of cells does the ABL have

Fibroblasts interlaced with melanocytes

41

T/F: In the ABL the iris is porous (no anterior limiting layer)

True

42

What gives us a blue iris

Light scatter in uniform space across stromal tissue

43

Why do most newborns start out with blue eyes then turn dark?

Because they haven't developed pigment yet

44

What causes dark irises?

Development of anterior stromal melanocytes and production of pigment

45

Blood flow of the iris is derived from

ophthalmic artery from two long posterior ciliary arteries and anterior ciliary arteries.

46

The anterior ciliary arteries run along the

Rectus muscles

47

T/F: the iris doe not bleed when its cut

True

48

There are 2 anterior ciliary arteries in each rectus muscles except for

Lateral rectus (it only has 1)

49

Allows for little distension and folding of vessels during constant movement of iris

Perivascular collagen sheaths

50

T/F: Perivascular collagen sheaths are unique to iris vessels

True

51

T/F" Humans react to light stimulation of the retina rather than the iris.

True

52

Light reflex is an important test to discover the integrity of the

-retina
-optic nerves
-chiasm
-optic tracts

53

The entire stimulus response function resembles a ___curve

S curve

54

The latency time becomes ____ with dimmer light stimuli

More prolonged

55

In scotopic and photopic conditions, the pupil_____with variability in light

Doesnt really change all that much

56

In mesopic conditions, the pupil_____with variability in light

Changes a lot

57

In the dark adapted state, the threshold light of intensity needed to produce a pupil contraction becomes ___ as rods are brought into play

Less

58

T/F: Rods in the dark adapted state do not produce as much increase in pupil contraction in response to increases in stimulus intensity

True

59

In dark-adapted eyes, pupillary reactions occur at intensities

Below photopic range

60

In dark adapted eyes the parafovea and peripheral are ____ sensitive than the fovea

More

61

In normal light adapted eyes, pupillary threshold is

Much higher

62

In normal light adapted eyes, the fovea is ___reactive than the periphery

More

63

T/F: the pupil has a max speed to contract

True. Not matter the intensity of light the pupil will contract at the same speed

64

What is the max speed of pupil contraction?

4 Hz

65

T/F: The pupil has to be able to see a stimulus long enough for it to react

True

66

With longer duration of a stimulus, the pupil contracts___, there is a ___latency time, and the contraction lasts ___

-contracts more
-shorter latency times
-contraction lasts longer

67

The pupil is more constricted when the light covers a ____ area and when light is ____bright

Covers a greater area and light is equally bright

68

T/F: Pupils sums afferent impulses regardless of spatial distribution, both rods and cones.

True

69

Under dark adaptation, the fovea shows ___ sensitivity compared to surrounding retinal areas because of the lack of rods

Decreased

70

In mesopic and photopic adaptations the pupil responds greatest in the ___ field

Central

71

T/F: the temporal field response is usually greater than the nasal field response

True

72

The peak sensitivity under photopic conditions is

Green 550

73

The peak sensitivity under scotopic conditions is

Blue

74

The greater the spatial frequency, the ___ the pupil contracts

Less

75

20/20 has a ___ spatial frequency

High

76

T/F: The pupil responds to motion even when the light level stays the same

True

77

Some people think that myopes have ___ pupils and hyperopes have ___ pupils

Myopes: larger pupils
Hyperopes: smaller pupils

78

Larger pupils can result in what 2 things

-Image degradation
-glare

79

If the pupils are too small (<2mm) what 2 things can effect visual performance

-diffraction limited
-reduced illumination

80

What is the optimal pupil size?

2mm

81

Does pupil size increase of decrease with age?

Decreases

82

The pupil diameter can vary between?

2-8 mm

83

What is the near vision triad?

Convergence, miosis, and accommodation

84

What is the 3rd nerve nucleus?

Eddinger-Westphal

85

Amplitude for young people is ___ to contraction from bright light

Equal

86

Is iris sphincter and dilator muscle is derived from

Neuroectoderm

87

The iris sphincter is predominately innervated by

The parasympathetic system

88

The iris dilator is predominately innervated by?

The sympathetic system

89

T/F: the sphincter and dilator muscle are equally strong

True

90

When are the pupils smaller?

During sleep and death

91

When are the pupils bigger?

During waking hours and when frightened

92

What 3 things can elicit a pupillary dilation?

-sensory
-emotion
-mental

93

If something is less arousing how will this effect a pupillary reaction?

There will be less of a pupillary response

94

If you are infuriated, will you have a greater or lesser pupillary reaction?

Greater

95

What are some findings of pupil size in adults

-they can still respond fully to mydriatic drugs
-pupils are still round and smooth
-light reflex remain brisk
-reduction is size is a linear process
-no change in thickness of dilator muscle with age
-decreasing pupil size begin in healthy eyes with strong levels or accommodation and brisk reactive pupils

96

If someone has horners syndrome what happens to the pupil when you put cocaine in their eye?

The horners pupil dilates less than the normal pupil

97

What does cocaine do to the eye?

blocks the reuptake of post-ganglionic norepi
resulting in the dilation of a normal pupil from retention of norepi in the synapse.

98

What can high levels of infrared do to the eye?

It can burn any ocular structure and have very deep penetration

99

What layer of the iris absorbs heat?

The black pigment of the posterior iris layer

100

When stimulated directly by heat, what happens to the iris sphincter?

It contracts

101

If the iris ensues, what may occur?

Long-lasting miosis

102

T/F: the ciliary body contains the minor arterial circle of the iris

False

103

What is the most posterior structure when looking doing gonio?

Ciliary body

104

What is the most anterior structure when doing gonio?

Schwalbes line

105

Name the order from anterior to posterior when doing gonio

Schwalbes line--> trabecular meshwork --> scleral spur --> ciliary body

106

Name the 4 functions of the ciliary body?

-accommodation
-aqueous production
-aqueous outflow
-indirectly causes iris contraction

107

What does aqueous production do?

Supplies nutrients to the lens and cornea

108

What does aqueous outflow do?

-Maintains IOP
-removes waste products

109

What are the 3 main process to produce/secretary aqueous humor?

-diffusion
-ultrafiltration
-active secretion

110

The stroma within the ciliary processes contains a dense network of ____ capillaries, and the number and shape of the processes provides a large ____ for secretion into the posterior chamber.

-fenestrated capillaries
-large surface area

111

Active secretion accounts for ___ of aqueous production

80-90%

112

What is the most significant factor in aqueous production?

Active secretion

113

What facilitates water movement

-coordination of ion pumps, channels
-cotransporters in the 2 epithelial
-aquaporins

114

What primarily drives secretion in the posterior chamber?

Movement of Na+ and Cl-

115

What has an indirect role in moderating the Cl flux

Bicarbonate

116

What is the rate of aqueous production?

2.5 ul per minute

117

This substance is a metabolic waste produce of glycolysis of the lens and cornea and is in high concentrations in the aqueous

Lactate

118

Ascorbate concentration is ___ higher in the aqueous than in blood plasma

20x

119

If aqueous produced more during the day or night?

Day. Decreased 50% at night

120

T/F: Dilating and constricting blood vessels can influence aqueous blood vessels by increasing and decreasing blood volume.

True

121

Diameter of zonular fibers

70-80mm

122

Elastic fibers that stabilize the lens and allows fluid to flow from the posterior chamber to the vitreous. And attaches to the lens

Zonular fibers

123

When is accommodation lost?

Age 50

124

Describe accommodation

Contraction of the longitudinal fibers of the ciliary muscle pulls the choroid forward, and contraction of the circular fibers draws the CB closer to the lens, decreasing the diameter of the ring formed by the CB. This releases tension on the zonule fibers and allows the lens capsule
to adopt a more spherical shape.

125

During accommodation the lens ____ ,the anterior surface curve ____, zonular fibers ____, the lens capsules becomes a more ___shape, and _____ refractive power

The lens thickens
The anterior curve increases
Zonular fibers relax
Lens capsule becomes more spherical shape
Increases refractive power

126

When looking at a distance, the ciliary muscle is ___ and the zonular fibers are ___

The ciliary muscle is relaxed
The zonules are pullin on the lens capsule

127

Pilocarpine cases ciliary muscle ____

Contraction

128

Does accommodative amplitude decrease or increase with age

Decrease

129

What stimulates miosis

Accommodation and convergence

130

Subjective measurements of accommodation rely on

Perception of clarity

131

Objective measurements of accommodation can be obtained with an

Autorefractor or aberrometer

132

T/F: dynamic measurements are better than static measurements

True

133

What really effects presbyopic eye movement?

The lens becoming thicker and stiffer

134

T/F: reduced near vision is caused by significant reduction in strength of ciliary muscle

False. It is not caused by it

135

What are some structural changes in the aging eye that could lead to reduced contractile force?

-thickening of tendons
-reduced muscle mass
-increased connective tissue

136

T/F: Measurements of contractile strength of ciliary muscle strips with stimulation show no reduction with increasing age.

True

137

In presbyopes are there changes in M receptor numbers, binding affinity, or ACh activity?

No

138

Loss of the ability to accommodate

Presbyopia

139

Ciliary muscle contractive power ___ up until age that
presbyopia manifests.

Increases

140

Are there changes in zonular length with age?

No

141

What is the limiting factor for accommodation

The movement and shape of the lens

142

Why can ciliary muscle contraction change the configuration of the TM?

And what does this do?

Because some of the longitudinal fibers are attached to the TM sheets

Facilitates aqueous movement through the anterior chamber angle structures

143

What is the max reductions of IOP when dealing with accommodation?

2.38mmHg

144

The ciliary muscle is derived from

Mesoderm

145

Describe the Tyndall phenomenon

-When breakdown of blood-aqueous barrier occurs, cells and flare become visible.
-Often immune factors, leucocytes.
-Usually whitish
-Can form hypopyon

146

What is hyphema?

-Trauma to head or injury such as whiplash can tear/ break the iris
-This can break the iris blood vessels entering from the major circle of
the iris
-Blood settles inferiorly.

147

A clear, colorless fluid that fills the anterior
and posterior chamber of the eye

Aqueous Humor

148

What are the 4 functions of the AH?

-Supplies nutrients and oxygen to and remove metabolic wastes from the anterior intraocular tissues such as cornea, lens and TM
-Inflates the eye globe and creates an IOP for normal optical functioning of the eye
-Transports ascorbic acid(AA) into anterior segment where it
serves as an antioxidative agent
-Facilitates the local immune responses during inflammation and
infection

149

What is the primary site of AH formation?

Pars plicata

150

Which layer of the CE is necessary for AH formation?

Non-pigmented epithelium

151

What is the major mechanism of solutes across CE?

Active transport

152

What drugs reduce aqueous humor formation?

CAI and alpha 2 agonists

153

Which one has a higher concentration of protein? (Blood plasma or aqueous humor)

Blood plasma

154

Which one has a higher concentration of ascorbic acid? (Blood plasma or aqueous humor)

Aqueous humor

155

Beta 2 agonist ___aqueous humor formation

Increases

156

Is AH average rate of formation greater or less during the daytime?

Greater (2.75 ul/min)

157

What is the pathway (5 steps) of the blood to the AH?

1.) Blood flow-->vascular bed of ciliary stroma
2.) Loading of solute from the ciliary stroma blood into the PE cells
3.) Translocation of solute through the gap junction into the NPE
cells
4.) Exclusion of solute from the NPE cells to the posterior
chamber (driven by an electrochemical gradient and/or by
active transport)
5.) The osmotic gradient established by the solutes facilitates the
passive flow of water into the posterior chamber by osmosis

158

What are the 3 mechanisms of solutes across the CF?

-Diffusion
-ultrafiltration
-active transport

159

Defined as the passive movement of solutes across the CE in response to a concentration gradient

Diffusion

160

defined as the passive movement of water and water soluble substances across cell membranes as a result of the hydrostatic and oncotic pressure between the ciliary stroma and the AH

Ultrafiltration

161

an energy-consuming process involving the movement of solutes across the CE against their concentrations gradients

Active transport

162

Will people who smoke marijuana have increased or decreased IOP?

What causes this?

Decreased IOP

9-THC

163

Is IOP constant throughout the day?

No

164

Why don't we want a lot of protein in the AH?

Because we want to keep transparency

165

What is the major part of the blood aqueous barrier?

Tight junctions between NPCE cells

166

What 2 things are allowed to pass to the posterior chamber?

Ions and water

167

What is a part of the primary vitreous

Hyaloid artery

168

What are the 3 conditions with remnants of the hyaloid artery?

-cloquets canal
-bergmeisters papillae
-mittendorfs dot

169

What is the outermost zone of the vitreous?

Vitreous cortex also called hyaloid surface

170

What is the center zone of the vitreous called?

Cloquets Canal (hyaloid canal)

171

What is the intermediate zone of the vitreous?

Inner to the cortex and surrounds the center canal

172

Where does AH come from?

Blood plasma

173

Barrier to the movement of intermediate- and high-
molecular weight substances such as protein.

Blood aqueous barrier

174

Barrier protecting the eye from entry of toxic substances and maintaining the homeostatic control

Blood aqueous barrier

175

Barrier that explains why drugs administered orally
or IV can hardly reach therapeutic levels in
intraocular tissue

Blood aqueous barrier

176

Tight junctions are present in the ____ ciliary epithelium

Non-pigmented ciliary epithelium (NPCE)

177

Other than NPCE where are tight junctions also present?

- in the iridial vascular endothelium
-between the iris epithelial

178

Endothelial of the inner wall of _____ are tight joined to prevent retrograde movement of solutes and fluid from the canal lumen into the AC

Schlemms canal

179

Tight junctions between NPCE cells constitute an effective barrier to intermediate and high molecular weight substances such as ____

proteins

180

What happens to the aqueous when there is a breakdown of the BAB?

And what cells may also be present?

Aqueous becomes cloudy due to leakage of plasma proteins into the posterior chamber (PC) and anterior chamber (AC).

Inflammatory cells may also be present.

181

In anterior uveitis what 2 things will you see?

Cells and flares (proteins)

182

Breakdown of the BAB can cause what 2 eye conditions?

- Anterior uveitis
- hyphema

183

Blood in the anterior segment due to trauma

Hyphema

184

What are 4 ocular injuries that causes or is caused by BAB breakdown

-Surgical and non-surgical traumas
----hyphema
-Intraocular inflammation (such as uveitis)
-Vascular and systemic disorders (such as diabetes)
- Intraocular tumor

185

is usually defined as an IOP of 5 mm Hg or less (extremely low pressures)

Ocular hypotony

186

When there is ocular inflammation what 2 things are releases?

-cytokines
-growth factors

187

Clear gel which occupies the posterior compartment of the eye.

Vitreous

188

The vitreous is located between the ___ and the ___

Retina and lens

189

The vitreous occupies ___ of the volume of the eye

80%

190

Light initially entering the eye through the
cornea, pupil and lens, is transmitted through the
____ to the ____

Vitreous --> retina

191

3-4 gestational stage of the vitreous

Primary vitreous

192

6th gestational week of vitreous

Secondary vitreous

193

Zonular fibers are in the ___ vitreous

Tertiary

194

Is secreted by NPCE of pars plana and persists in the
adult as the suspensory ligament of the lens

Zonular fibers (tertiary vitreous)

195

Optic cup filed by a system of fibrillar material, presumably secreted by embryonic retina cells is during what stage of vitreous development?

Primary vitreous

196

VEGF released by lens induces vasculogenesis; Hyaloid artery penetration is a part of what vitreous developmental stage?

Primary vitreous

197

Vitreous stage where Anti-angiogenesis factor present, Hyaloid vessels retract, Vitreous gel body formed

Secondary vitreous

198

arises from the center of the optic disc, consists of a small tuft of fibrous tissue and represents a remnant of the fetal hyaloid artery.

Bergmeister's papillae

199

small, circular opacity on the posterior lens capsule, classically nasal in location, which represents the anterior attachment of the hyaloid artery.

Mitterndorfs dot

200

a tubular structure containing remnants of the primary vitreous, located between the posterior aspect of the lens and the retina in the vicinity of the optic disk

Cloquets canal (hyaloid canal)

201

The pigmented and nonpigmented CE are connected by

Gap junctions

Apex to apex

202

The middle layer of the eye

Uvea

203

What are the 3 regions of the uvea?

-iris
-CB
-choroid

204

The choriod extends from the ___ to the ___

Ora serrata to the optic nerve

205

The choroid is located between the ___ and the ___

Sclera and retina

206

Layer of the choroid that is thin, pigmented, connective tissue

Suprachoroid

207

Pigmented, vascularized, loose connective tissue that contains melanocytes, fibroblasts, macrophages, lymphocytes, mast cells

Large and medium vessels

208

A later of the choroid that is a single layer of fenestrated capillaries

Choriocapillaris

209

This layer of the choroid fuses with the retina multilaminated sheet

Bruchs membrane

210

____choriod absorbs excess light

Darkly pigmented

211

Provides nutrients to and remove the waste products from outer retina

Vascular choroid

212

Sole blood supply to the fovea

Choriocapillaries

213

Provides a pathway for the posterior vessels that supply the anterior segment

Suprachoroidal space

214

A branch of the ophthalmic artery

Ciliary artery

215

What are the 2 branches of the ciliary artery

Short posterior ciliary artery and long posterior ciliary arteries

216

Long ciliary nerves carries ___ and ___ fibers

Sensory and sympathetic fibers

217

Short ciliary nerves carry ___ and ___fibers

Sympathetic and parasympathetic

218

Provides a pathway for the nerves that supply the anterior segment

Suprachoroidal space of choroid

219

If someone has a hyperopic defocus the choroid will be ___ and the growth is ______

Thin choroid and growth increased

220

If someone has a myopic defocus the choroid will be ___ and the growth is ______

Thick choroid and growth decreased

221

The choroid can ___ modulates its thickness, varying the position of the retina and the state of focus of the eye

Rapidly

222

What are the 4 functions of the choroid?

-Provide nutrients and remove the waste products from outer retina
-Passage of nerves and vessels
-Absorption of excess light
-Regulate emmetropization (study in chicken)

223

What are the 3 changes in the iris?

-loss of pigmentation
-dilator muscle becomes atrophic
-sphincter muscle becomes sclerotic

224

What are the 2 aging changes in the ciliary body

-elasticity decreased due to the amount of connective tissue increased within the layer of the CB
-formation of aqeuous humor decreases with aging

225

What are the 3 aging changes in the choroid?

- choriocapillaries decrease in density and diameter-->choroidal blood flow decreases
- bruchs membrane increases in thickness
-various substance and particles accumulates in bruchs membrane

226

Nutrients from the choriocapillaries and waste product from the retina pass through what structure?

Bruchs membrane

227

Name the 5 layers of the bruchs membrane

1.) interrupted basement membrane
2.) outer collagenous zone
3.) elastic layer
4.) inner collagenous zone
5.) basement membrane of RPE cells

228

Calcification and the yellow deposits in the inner collagenous layer of Bruch’s membrane. Made of the remaining damaged cells (called lipofuscin) from the oxidative stress.

Drusen

229

yellow-brown pigment granules composed of lipid-containing residues form oxidative stress

Lipofuscin

230

Does the accumulation of drusen make Bruchs hydrophobic or hydrophilic?

Hydrophobic

231

T/F: the accumulate of drusen inhibits the passage of metabolites

True

232

Accumulation of water between RPE and bruchs membrane causes _____

Detachment

233

Stage of ARMD where the choroid still functions

Dry ARMD

234

What layer of the choroid is multilaminated sheet and fuses with RPE?

Bruchs membrane

235

What provides blood to the fovea region?

Choriocapillaries

236

What part of the retina receives blood supply from choroid?

Outer retina

237

Which layer of the choroid proves a pathway for the vessels and nerves that supply the anterior segment?

Suprachoroidal space

238

Which layer of Bruchs membrane does drusen deposit?

Inner collagenous zone

239

Bruchs membrane thickness ___ with aging

Increases

240

With pupil constriction you have a ____depth of field

Larger

241

Low concentration of proteins in aqueous helps prevent ___

Light scatter

242

Are there large amounts of protein in the aqueous?

No