Full Review Flashcards
(245 cards)
1
Q
During gestation, when does the eye form?
A
Between 1st and 4th months of gestation
2
Q
What forms during gestation weeks 3-4?
A
Eye fields
Optic vesicle
3
Q
What forms during gestation weeks 5-6?
A
Optic cup
Lens vesicle
Choroid fissure
Hyaloid artery
4
Q
What forms during gestation weeks 7-8?
A
Cornea
Anterior chamber
Lens
Retina
5
Q
What forms during gestation weeks 8-10?
A
Eyelids
6
Q
What forms during gestation weeks 9-15?
A
Iris
Ciliary body
7
Q
The eye fields form from a population of what cells?
A
Cells from the anterior neural plate
8
Q
In humans, when do the frontal eye fields begin to form?
A
Around 17 days
9
Q
Where do the eyefields start to form?
A
In the prosencephalon
10
Q
As the eyefields get pushed forward, what begins to occur?
A
Folding, bringing the eyefields together
11
Q
After folding of the eyefields, what beings to form?
A
Optic groove
Eye fields are invaginating and forming a sulcus
12
Q
How long does it take for the neural folds to meet at the top?
A
25 days
13
Q
What structure forms the optic vesicle?
A
Optic groove
14
Q
When the neuroectoderm and the surface ectoderm come in close contact (around day 25), what happens?
A
The optic groove begins to push itself out (evaginates), creating the optic vessicles
15
Q
Neuroectoderm coming in contact with surface ectoderm induces what?
A
Lens placode
16
Q
What does the lens come from?
A
Surface ectoderm
17
Q
True or false: formation of the optic vesicle occurs at the same time as induction of the lens placode.
A
True
18
Q
When the lens placode is induced, does it begin on the outside, or the inside?
A
Outside
19
Q
How does the lens get inside the eye?
A
Lens placode and and optic vessicle invaginate
20
Q
When the lens vesicle invaginates with the optic vesicle, what forms?
A
A bi-fold
21
Q
When the optic vesicle invaginates, what is formed?
A
Optic cup
22
Q
When the lens placode invaginates, what is formed?
A
Lens vesicle
23
Q
As the optic vesicle and cup form, what is occurring to the optic stalk?
A
Also ingavinating
24
Q
Where the optic stalk invaginates, what is created?
A
Choroid fissure
25
What grows within the choroid fissure?
Hyaloid artery
26
What feeds the lens vesicle during formation?
Hyaloid artery
27
What surrounds the back of the lens?
Hyaloid artery
28
What is the role of the posterior lens fiber?
Obliterate the lens cavity
29
When does the cornea differentiate?
After the differentiation of the lens and retina - around one month
30
What serve as the scaffolding for creating the iris?
Iridopupilary membranes
31
When do we first see something that actually resembles an eye?
After one month
32
When do the pupilary membranes usually go away?
After birth
33
What happens if the pupilary membranes persist after birth?
They may fix the pupil, and make it so it can't change size
34
What keeps the lens nice and smooth?
Crystallines
35
During development, is the cornea clear or opaque?
Opaque
36
What cells form the outer corneal epithelium?
Surface ectoderm
37
What cells form the inner portions of the cornea?
Neural Crest Cells
38
All of the structures of the eye, with the exception of _____, come from the ectoderms.
Hyaloid artery
| Inner layer of the cornea
39
During weeks 7-8, what is occuring in the retina?
There is a gap between RPE and neural retina. Neural retina begins to differentiate into the 10 total cell types
40
When the eyelid first is formed, is there a fissure?
Nope. It is just one structure
41
During what trimester do the eyelids un-fuse?
3rd trimester
42
From what tissues does the iris form?
Optic cup tissues
43
The folding of the "rim" of the optic cup forms what two structures?
Iris
| Ciliary processes
44
What are the two principle pathways from progenitor cell to retinal cell?
Ganglion cell pathway
| Cone/horizontal cell pathway
45
What cells can arise from the ganglion cell pathway?
Ganglion cells
Amacrine cells
Rods
Bipolar cells
46
What cells can arise from the cone pathway?
```
Cones
Horiztonal cells
Muller glial cells
Rods
Bipolar cells
```
47
Both the ganglion and cone cell pathways may differentiate into what?
Bipolar cells
| Rods
48
Which retinal cell types migrate more than the others?
Bipolar cells
| Rods
49
Which cells are "born" at about the same time?
Amacrine
Cone
Ganglion
Horizontal
50
Which cell type begins to form after the amacrine, cone, ganglion, and horizontal cells are formed?
Rods
51
What retinal cell type is born after rods?
Bipolar cells
52
What is the last retinal cell type born?
Muller glial cells
53
What is the order of retinal cell birth?
1. Amacrine, cone, ganglion, horizontal
2. Rods
3. Bipolar cells
4. Muller glial cells
54
Which cells continue to be born after birth?
Amacrine, rods, bipolar, Muller cells
55
Which cells are largely born before birth?
Cones
Ganglion cells
Horizontal cells
56
What does the retina start as?
A mass fo progenitor cells
57
Where to the progenitor cells reside?
In the ciliary regions
58
What creates the optic nerve?
Axons of the ganglion cells
59
Where do the ganglion cells migrate to?
Thalamus
60
What cells are responsible for forming the barrier of the outer nuclear layer/outer plexiform layer?
Horizontal cells
61
Which retinal cell layer is one of the first specified?
Ganglion cell layer
62
Which cells "give a ride" to many of the migrating retinal cells?
Radial glial cells
63
Which cells start having the first neurotransmitter vesicles forming?
Horizontal and amacrine cells
64
Cones make contact with which cells first?
Horizontal cells
65
What forms the second synapses?
Off BP cells to cones
66
After off BP cells synapse to cones, what other synapses begin?
Ribbon synapses (on BP to cones)
67
Where do glutamate receptors appear first?
Off BP cells
68
Which cells have the strongest on response?
Amacrine cells
69
As the vision system develops, there are many connections being made all over the place. What must occur before it functions properly?
Pruning
70
What are the first responses that occur in the developing eye?
Excitatory - occurs in the dark
71
Center-surround organization of receptive fields is apparent as soon as ___ are detected.
Light responses
72
Turtles are initially ___. (anisotropic; isotropic)
Anisotropic
73
Dark-rearing mice until about 3 weeks after birth leads to an increase in the fraction of what?
Bistratified, On-Off ganglion cells in the retina
74
If you suture a kitten's left eye, what happens in the cortex?
The ocular dominance columns will shift, so that there aren't any cells for the left eye, and they all go to the right.
75
What happens if you suture a cat's left eye closed 12 weeks after birth?
The response of cells is even in each ocular dominance column, but the number of cells is reduced.
76
If you suture both eyes closed at birth, what happens to the cells in the cortex?
There is a normal distribution of cells; ocular dominance columns are in tact, but they don't work correctly. Many don't work at all.
77
If you suture an eye during the critical period, but open it before the critical period ends, what will happen?
They affected eye will not recover
78
After suturing an eye during the critical period, what is the only way to recover brain function?
Reverse suturing before the critical period ends
79
What happens if you raise monkeys in darkness (binocular occlusion) from 2 weeks old up to 3-6 months?
Deterioration of the visual cortex - they behave as if they are blind, and never fully recover
80
After 1 year, what effect will reverse suturing have on a monkey?
No effect
81
When do babies begin to see clearly?
4-6 months
82
When do babies begin the "hand to mouth" movement?
8-12 months
83
How much accommodation do babies have at birth?
None - poor ciliary muscle control
84
What is a baby's VA at birth?
20/600
85
At what age are babies capable of focusing an image on the retina, but it is still blurry?
2-3 months
86
At 2-3 months, why is the image still blurry for a baby?
The photoreceptors are still getting organized. Some cells are still being "born"
87
What VA is "expected" around 3 months?
20/200
88
Once photoreceptors are born, they still need to mature. What needs to occur?
Their outer segments still need to elongate
89
Why is a "newborn" photoreceptor less effective than a mature one?
The outer segments are short, so there is less surface area to catch photons
90
According to Ricco's law, is the threshold area larger or smaller as an adult than as a child?
Larger as an adult
91
Compared to adult levels, in the 1st month, a baby is __ times less sensitive to light.
50
92
Compared to adult levels, in the 3rd month, a baby is __ times less sensitive to light.
10
93
Why are babies more attracted to bright colors?
They are less sensitive to light, so the brighter the color, the easier they can see it
94
During the first week of life, what wavelengths are babies missing?
Shorter wavelengths (they already have long wavelength cones)
95
Which of the cones is last to develop?
Blue cones
96
What contrast difference is a 1 month old able to discriminate?
5%
97
What contrast difference is a 2 month old able to discriminate?
0.5-0.75%
98
When do babies eyes begin to fixate, coordinate movement, and have some smooth tracking?
3 months
99
What develops that allows a baby to track smoothly?
Myelination of the axons, allowing signals to travel faster
100
What is an important component of recognition for a baby?
High contrast
| Ex. hairlines, edges of faces
101
By _ months, fixation occurs.
2 months
102
When do babies begin to mimic smiles?
2 months
103
What visual developments are occurring around ages 4-6 months?
Acuity
Color
Movement
Recognition
104
What is a baby's VA at 4 months?
20/100
105
When do babies begin to see blue hues?
Around 4 months
106
When does real tracking and hand-eye coordination begin to occur?
4 months
107
At what age will a baby hesitate when presented with false depth cues? (baby checkerboard drop-off experiment)
4-6 months
108
At age 4-6 months, saccades and pursuits may occur at a rate of ___.
200-250 milliseconds
109
What is the difference between a baby's saccades/pursuits and an adult's?
There is a lag in initiation
110
When do babies begin to recognize strangers and faces?
6 months
111
What change is facilitating the development of saccades, facial recognition and the like?
Neuronal branching
112
What causes the brain to grow and branch?
Extrinsic factors - retina sending more info to the brain
113
At what age is the optic nerve myelinated?
4-5 months (but still not fully functional yet)
114
When do babies start associated and using different depth cues?
8-12 months
115
When does VA improve to 20/30?
8months-1 year
116
If a child is going to be an emmetrope, when will they see 20/20?
Abot 36 months
117
What aspects of vision development are fast?
Color
| Visuomotor
118
What aspects of vision development are slow?
Acuity
| Coordination
119
Does a baby have stereo at birth?
Nope
120
When does stereo begin to emerge?
3-4 months
121
When is adult level stereo reached?
6 months
122
Most visual systems have kicked in around 6 months, except for which 4 things?
Grating acuity
Color vision
Vernier acuity
Contrast sensitivity
123
What does grating acuity test?
Resolution acuity
124
What is another name for Vernier acuity?
Hyperacuity
125
What are the 3 ways to assess resolution acuity?
```
Visual evoked potential (VEP)
Optokinetic Nystagmus (OKN)
Preferential looking (PL)
```
126
What is the most rudimentary way of assessing resolution acuity?
OKN
127
What must occur in order to get a measurement with OKN?
Must be able to resolve the bars. If not, it just looks gray, and no fixation will occur.
128
Why is OKN the most rudimentary?
You don't need any V1 processing to get a reading. It is controlled by the region that controls oculomotor response
129
If a stimulus is received using a VEP, where will a response be elicited?
Primary visual cortex
130
What does a VEP recording look like 7 days after birth?
Nearly a flat line
131
When do you start to see a VEP response in babies?
Around 1 month
132
At what age does a VEP response look adult-like?
About 6 months
133
When using the VEP method, when does a baby "see" 20/20?
6-8 months
134
At one month, what should the FPL visual acuity and the Snellen equivalent be?
1 cycle/degree
| 20/600
135
At three months, what should the FPL visual acuity and the Snellen equivalent be?
3 cycles/degree
| 20/200
136
At six months, what should the FPL visual acuity and the Snellen equivalent be?
6 cycles/degree
| 20/100
137
At twelve months, what should the FPL visual acuity and the Snellen equivalent be?
12 cycles/degree
| 20/50
138
At 3-5 years, what should the FPL visual acuity and the Snellen equivalent be?
30 cycles/degree
| 20/20
139
What is the best card for VA in infants? It is really expensive...
Teller Acuity Card
140
What are the three preferential looking cards that can be used for infants?
Teller Acuity
Cardiff Acuity
Lea Grating Paddles
141
What does the Cardiff Acuity test for?
Contrast
142
When does forced choice preferential looking reach adult levels?
5-6 years
143
What are the limiting factors for VA development in infants?
Foveal cone immaturity
Incomplete myelination of the optic pathway
Cortical immaturity
144
When does the "macular dip" begin to be seen?
At birth
145
How long after birth does it take for the cones to be fully developed?
About 45 months
146
What happens in the central retina at about 16 weeks post natal?
4-8 fold increase in cone density
147
Volume and density of synapses dramatically ___ after birth.
Increase
148
When do foveal cones reach adult length?
4 years
149
When does foveal cone density reach adult level?
45 months
150
How long does it take for complete myelination of the optic pathway to occur?
2 years
151
Why is Vernier acuity called hyperacuity?
It is 10 times better than grating acuity
152
Which is worse at birth, Vernier acuity or grating acuity?
Vernier acuity
153
At what age does Vernier acuity surpass grating acuity?
4 months
154
When does Vernier acuity reach adult levels?
6-8 years
155
Which ethnicity has the highest incidence of myopia?
Asian (18.5%)
156
What ethnicities have the lowest prevalence of myopia?
African Americans
| Whites
157
What ethnicities have the highest prevalence of astigmatism?
Asians and hispanics
158
What are the risk factors for myopia progression?
```
Age
Family Hx
Amount of near work
Gender (female>male)
Race
```
159
When do ocularmotor functions reach adult levels?
3-6 months
160
When does accommodation reach adult levels?
3-4 months
161
When do convergence and fusion reach adult levels?
22 weeks
162
When does stereopsis reach adult levels?
6 months
163
Define amblyopia.
A condition in which the best corrected visual acuity is poorer than 20/20 in the absence of any obvious structural anomalies or ocular disease
164
Amblyopia is a Dx of ___.
Inclusion
165
What are the 3 amblyogenic factors?
Srabismus
Anisometropia
Image deprivation
166
What are the five aspects of visual function affected by amblyopia?
Reduced contrast sensitivity and visual resolution
Increased sensitivity to contour interaction effects (crowding)
Abnormal spatial distortions and uncertainty
Unsteady and inaccurate monocular fixation
Inaccurate accommodative response
167
What is isometropic amblyopia?
When both eyes have a similar, high refractive error
168
At how many diopters of cyl do you worry about anisometropia?
>1.50
169
At how many diopters of cyl do you worry about isometropia?
>2.50
170
At how many diopters of plus do you worry about anisometropia?
>1.00
171
At how many dioptes of plus do you worry about isometropia?
>5.00
172
At how many diopters of minus do you worry about anisometropia?
>3.00
173
At how many diopters of minus do you worry about isometropia?
>8.00
174
For amblyogenic strabismus to occur, what conditions must be met?
Constant strab
Unilateral strab
Onset before ate 8
175
What would be the expected VAs for a child that had their binocular congenital cataracts removed around 4-6 months of age?
20/50
176
With monocular form deprivation, where would you expect to see changes in the brain?
Cortex and LGN will both have morphological changes
177
What would be the expected VA for a child having had their monocular congenital cataract removed at about age 4-6 months?
20/400
178
When must a monocular congenital cataract be removed to still be able to recover VA up to 20/40?
2 months
179
What accounts for more than 90% of all amblyopia?
Strab
| Aniso
180
Which type of amblyopia doesn't show any contrast sensitivity loss?
Strabismis
181
Anisometropic amblyopes have contrast sensitivity loss at ___ spatial frequencies.
High
182
What three things may hyperopic isometropic amblyopia cause?
```
Accommodative esotropia
Normal vision (if accommodates well)
Bilateral refractive amblyopia if the child maintains binocularity by underaccommodating
```
183
What induced meridional amblyopia?
High astigmatism - usually bilateral
184
Why does WTR astigmatism cause less meridional amblyopia?
Pt. can squint to "fix" the blur
185
When is the peak of emmitropization?
Around age 6
186
When are the fastest changes occurring in the visual system?
Around age 2
187
What is the normal progression rate of myopia?
-0.50 per year
188
In strabismic amblyopia, where is VA loss the greatest?
At the fovea
| Also shows nasal/temporal asymmetry
189
What is the definition of crowding?
The recognition of a given character is degraded by the presence of neighboring characters
190
What factors affect the degree of crowding?
Separation between the characters
Character size
Location in the visual field
191
What mainly causes the amblyopic reading deficit?
Increased crowding effect
192
Describe fixation for anisometropic amblyopes.
Central and unsteady
193
Describe fixation for strabismic amblyopes.
Eccentric and unsteady.
194
How can fixation be measured in strabismic amblyopia?
Maxwell spot/Hadinger's brush
| Visuoscopy
195
Accommodation is __ secondary to amblyopia.
Reduced
196
What accommodative issues arise in amplyopic persons?
Reduced accommodation
Inaccurate and unsteady accommodation
Affect ability to do sustained reading and fine visual tasks
197
At what age do vehicle accidents increase and why?
Age 75 - slower response time
198
A smaller pupil causes people to be less tolerable to what?
Glare
199
With age, the smaller pupil causes problems adapting to what?
Changing light conditions
200
Elapsed time for glare recovery increases starting at what age?
60
201
The yellowing of the lens with age causes problems seeing which colors?
Short wavelength - blue, green, violet
202
What things help people with yellowed lenses to perceive color more accurately?
Using full spectrum hallogen or fluorescent bulbs
203
Yellowing of the lens may also cause a decrease in what?
Depth perception cues - contrast recognition problems
204
Whit is one of the first apparent aging changes in the retina?
Overall thinning
205
What things cause retinal thinning with age?
Loss of neuronal cells
| Shortening of the outer segments
206
What is usually the only real aging change in the fovea?
Change in the cones
207
Where are cones lost the quickest due to age? The slowest?
Quickest in the periphery
| Slowest in the fovea
208
What are the two pigments found in RPE?
Melanin
| Lipofuscin
209
What is the origin of lipofuscin?
Phagocytized PR outersegments
210
Which pigment increases the most with age: Lipofuscin or melanolipofuscin?
Melanolipofuscin (MLF)
211
Lipofuscin may be a causative agent for what?
AMD
212
Where does drusen form?
Between RPE and Bruch's membrane
213
Which type of drusen is a normal biproduct of age?
Hard drusen
214
When does color vision really start to go downhill?
Ages 65-90 - have a 50/50 shot at failing a D15 test
215
Stereo begins to decline at what age?
About 60
216
What factors contribute to a loss of contrast sensitivity around age 65?
Senile myosis
| Nuclear sclerosis
217
When does useful field of view drop off the most?
70-80
218
Why isn't aging a disease?
It isn't fully treatable
219
What is the most widely used aging strategy?
Replenishing
220
What are the 4 aging strategies?
Wishful thinking
Fixing
Replenishing
Strengthening
221
What are the four major age-related eye diseases?
Glaucoma
Cataracts
AMD
Diabetic retinopathy
222
What is the major problem that arises from diabetes?
Diseased blood vessels
223
What leads to a risk of developing diseases like diabetic retinopathy and glaucoma?
Blood vessels not function correctly, making it so that nutrients cannot reach the retina
224
What are the 3 stages of diabetic retinopathy?
Background diabetic retinopathy
Diabetic macular edema
Proliferative diabetic retinopathy
225
What occurs in diabetic retinopathy?
Blood vessels get blocked and cause small hemorrhages in the retina
New blood vessels are poor, and can lead to microaneurysms and leak
226
Which type of glaucoma can lead to rapid vision loss?
Acute glaucoma
227
What are the 4 types of glaucoma?
Chronic open-angle
Acute closed angle
Low-tension
Congenital
228
What is the most common cause of blindness in the United States?
AMD
229
Which form of AMD is less serious?
Dry - more common (90% of cases)
230
What occurs in wet AMD?
Neovascularization with blood leakage
231
Which AMD causes faster vision loss?
Wet AMD
232
Which gene is more associated with wet AMD?
CFH
233
Which gene is more associated with dry AMD?
HTRA1
234
People with both alleles had an increased chance of __% to get AMD by age 65.
47%
235
AMD generally affects whom?
Caucasian males ove age 50
| Smokers
236
What treatments are there for dry AMD?
None
237
What treatments are there for wet AMD?
Anti-VDGF (avastin, lucentis..)
Implantable telescope
Laser photocoagulation
Visudyne therapy
238
What is the cause of cataracts?
Sclerosis of the lens
239
What things increase the risk of cataracts?
Any Smoking
| Heavy Alcohol use
240
What is the cause of Fuch's dystrophy?
Deterioration of endothelial cells, leading to poor water drainage
241
What does Fuch's usually cause?
Swelling and shape change of the cornea
242
Why do patients with Fuch's usually wake up with blurry vision?
When the eyes are closed, the water cannot evaporate
243
What might you do to treat early Fuch's?
Salt-water eye drops to dry the eye
Blow hot air on cornea
Sof-bandage CL for corneal blisters
244
What is the treatment for severe Fuch's?
Corneal transplant
245
What is the first thing patients will notice if their RPE is dying?
Glare
