MODULE 5: VISUAL DEVELOPMENT Flashcards
True or False
Visual development is complete at birth
False
Changes occur within the anatomy and physiology of __________ and __________ system
ocular, cortical
Why is it important for optometrists to understand the age at which different visual functions first appear?
any delay in appearance of a particular function may indicate an underlying delay in maturation
Two techniques used to investigate the development of VA
Electrophysiological method (VEP)
Preferential Looking (PL)
What technique uses behavioral method?
Preferential Looking
Tests the integrity of the visual pathway from the retina to the cortex by recording brain activity through electrodes placed on scalp.
Visual Evoked Potential (VEP)
The origin of this test is based on observation that an infant would rather look at a pattern than a blank stimulus
Preferential Looking (PL)
This test is dependent on examiner’s ability and child’s attention
Preferential Looking (PL)
Preferential Looking approximate snellen VA in meters at birth
6/300
Preferential Looking approximate snellen VA in meters at 1 month
6/200-6/90
Preferential Looking approximate snellen VA in meters at 3 months
6/90 - 6/60
Preferential Looking approximate snellen VA in meters at 6 months
6/60-6/36
Preferential Looking approximate snellen VA in meters at 9 months
6/36-6/24
Preferential Looking approximate snellen VA in meters at 12 months
6/24
Preferential Looking approximate snellen VA in meters at 18 months
6/18-6/12
Preferential Looking approximate snellen VA in meters at 24 months
6/12-6/9
Preferential Looking approximate snellen VA in meters at 36 months
6/9-6/6
Preferential Looking approximate snellen VA in meters at 5+ years
6/6-6/5
VEP
approximate snellen VA at birth
Poor 1 cpd
VEP
approximate snellen VA at 2 months
2 cpd
VEP
approximate snellen VA at 3 months
3 cpd
VEP
approximate snellen VA at 6 months
6-20 cpd, 6/6
Tests used in getting contrast sensitivity
PL and VEP
Extremely immature at birth but develop substantially over the first few months of life
Contrast Sensitivity
CS reaches adult like values by ___________
7 month
____________ can detect changes in the orientation of stimulus
Newborns
Which gratings is preferred by newborns?
Horizontal
Oblique orientation on ________________
6 weeks of age
Infants less than 2 months of age have poor _____________
sensitivity motion
VEP responses to low velocity stimuli
10 weeks of age
Motion detection
Responses to stimuli four times fast at ___________
13 weeks
What is the first sign of visually impaired infants?
Abnormal eye movement
Sign of normal visual development or oculomotor function
Normal eye movement
Birth
Age first demonstrated: Vertical Up
4-6 weeks
Smooth pursuit - other term
Eye tracking
Ability of eyes to maintain focus on the target while it is moving
Optokinetic Nystagmus
True or false
Newborns have no fixed focus with accommodation
False
Newborns have fixed focus and no accommodation
Accommodation
Immature at _______
Mature at __________
2 months
7 months
2 types of vergence
Accommodative convergence and Fusional Vergence
Age first demonstrated: Smooth pursuit
6 months
Age first demonstrated: Optokinetic nystagmus
Birth
Age first demonstrated: vestibulo-ocular reflex
Birth
Oculomotor functions already demonstrated at birth
Horizontal Saccades, Optokinetic nystagmus, vestibulo-ocular reflex
Type of vergence driven by blur
Accommodative convergence
Type of vergence driven by diplopia
Fusional vergence
Present at 1 month of age, improves by 2 months
Accommodative convergence
Type of vergence intermittent at 2 months, improves in accuracy with age
Fusional vergence
3 levels of binocular function
Bifoveal fixation, fusion, stereopsis
Level of binocular function which only occur in state of orthophoria, usually develops at 3-6 months
Bifoveal fixation
Level of binocular function absent at 3.5 months, present at 6 months. This is the ability of brain to fuse images to form one single image
Fusion
Level of binocular function present at 2-6 months but not yet matured.
Stereopsis
Gross stereopsis develops at ___________
6 months
Fine stereopsis develops at __________
5 y/o
Stereopsis is measured through
Seconds of an arc —-> “
Stereopsis at 6 months
600”
Stereopsis at 12 months
210-170”
Stereopsis at 24 months
100-85”
Value
Stereopsis at 5 years
20”
What does “ means
Seconds of an arc
Color vision emerges _______
Between 1 and 3 months
Dichromat at
2 months
Trichromat at
3 months
Babies have preference for bright colors, specially ________
Red
Error of refraction present in newborns
Hyperopia
A newborn has a mean error of ____________
2.00 D
True or false
A mean error of 4.00 D is normal in newborns since babies have short axial length
False
A mean error of 2.00 D is normal in newborns since babies have short axial length
True or false
Prematures are more hyperopic
False
Prematures are less hyperopic
Hypermetropia increases from birth until ______ months then gradually decreases towards emmetropia at about ______ y/o
6; 6
Which of the following does not happen during emmetropization?
A. Lumalaki lens
B. Nageexpand vitreous chamber
C. Bumababa power
D. Nagfflatten cornea
E. Nageelongate ang mata until 6 y/o where nagiging 24mm
F. From 2D unti unti nagiging plano
G. Nagiging steeper ang cornea
G.
At what age does a person becomes completely emmetropic?
16 y/o
Emmetropia usually achieved by 16 years and then nagkakaroon ng ____________
Myopic shift
Type of astigmatism present in infants
Against-the-rule
True or False
Astigmatism is common in infants than adults, significant amounts common under 3.5 years of age
True
At____________, astigmatism drops significantly and shift from against to with the rule
3.5 years
What is the normal axial length of a newborn?
16.5mm
Axial length of newborn grows by _________ in the first 6 month
4mm
At 2-5y/o, _________ is added to the axial length of a newborn
1mm
At 5-13 y/o, _________ is added to the axial length of a newborn
1 mm
What causes the drop of astigmatism in newborns?
Blinking
Normal corneal power of newborn
52D
Cornea flattens until it reaches adult values of __________ at ___________
42-44D at 12 mos
Normal HVID in newborn
9.5 mm
Normal horizontal diameter in adults
12mm
Normal central corneal thickness in newborn
0.96mm