MT 1 Flashcards
Germinal periods times
Day 1-21
Embryonic period
4-8 weeks
Fetal period
9 weeks to birth
what happens during the germinal period
Fertilization to zygote. Rapid cell division begins differentiation. Inner=ectoderm, endoderm, mesoderm. Outer forms with implantation and create placenta
Day 10
Implantation occurs in the uterus (42% survival rate here)
Day 21
neural tube forms
Ectoderm form what in the eye
RPE, Retina, Optic nerve, lens
Mesoderm forms what in the eye
Uveal tract, sclera, cornea
What is the most critical period of prenatal development
embryonic
what happens during the embryonic period
differentiation of all major internal and external body structure and vital organs. Growth occurs in a cephalon to caudal and proximal to distal way. Chromosomal abnormalities cause spontaneous abortion in 20%.
What happens during Fetal period
Growth stage: sexual differentiation by week 12. Further differentiation and refinement of ocular structures. Myelination of CNS begins. Brain waive pattern shifts to active cycles at 28 weeks
What is the age of viability
24-28 weeks
What is a normal term
38 weeks
4 types of congenital disorders
Genetic in origin (any stage), genetically determined by enviormenteally induced, purely environmental, sporadic (unknown)
Greatest risk for chromosomal abberations
maternal age.
Chromosomal abberation viable births
all share a syndrome
Cause of chromosomal abberations
90% environmental and 10% genetic
Retinoblastoma
Germaine deletion or translocation of the long arm of 13. Results in loss of function of RB1 gene.
Retinoblastoma inheritance
Typically AD
Cri-Du-Chat
5p syndrome. Short arm of 5 gone. High pitched cry like a kitten. Hypertelorism. microcephaly, optic atrophy, severe mental retardation.
Single gene mutations that are autosomal dominant
each offspring has 50% chance. Vertical pattern seen in families.
Autosomal recessive single gene mutations
Need 2 defective genes to express. Appears sporadically with a horizontal pattern in family tree.
Single gene defects are ____
rare. Most humans traits are determined by multiple genes and factors.
Multifactorial genetics
Specific genes in specific cells turn on and off in response to trauma, pathogens, neurochemicals, oncogenesis.
Teratogens
Range of substances and conditions that increase risk of prenatal anomalies. Effects of exposure vary according to timing. Each structure has its own critical period where it is most susceptible. Also varies effect due to threshold. Also has an interaction effect (i.e. smoking and alcohol) and genetic vulnerability.
When is the eye most susceptible to tetragens
4th week but anomalies can arise at any time.
Specific Tegragens
infectious agents, medicinal drugs, hyperthermia, psychoactive drugs, maternal age and health
Infectious Agents
Mother’s immune system must necessarily be suppressed to accept the fetus. Infectious agents can be transmitted prenatal, perinatal (during birth) or postnatal.
Infectious agents that can be passed to child.
TORCH dz. Toxo, other (syphillis, hep b, coxsackie, epstein bar, varicella), Rubella, cytomegalovirus, herpes simplex virus.
Toxo
30% affected mothers will transmit to chid. Children will have chorioretinitis. Most affected babies are asymptomatic at birth. Hydrocephalus, cerebral calcification, microcephaly, deafness, seizures.
Rubella
Transmitted during first trimmest (7 weeks). Includes cataracts, salt and pepper retinopathy, a heart defects.
Cytomegalovirus
Most asymptomatic at birth but go to develop cerebral calcifications, atrophy, sensorineural hearing loss, seizures, and chorioretinitis.
HIV
Transmitted to baby during birth. Risk is higher if mother is exposed during 3rd trimester.
Visual consequences of TORCH dz
Severe encephalopathy often leads to permanent damage to visual processing areas and leads to cortical vision impairment. Optic atrophy is also common.
Drugs and pregnancy
Ocular diagnostic drugs have a risk so discuss with patient.
Hyperthermia
Maternal fever at critical period can cause microphthalmost, CNS and facial defects.
psychoactive drugs
Due to the interaction of tetragens, poor or nonexistent prenatal care, poor nutrition, high stress levels, poor lifestyle after birth. unknown.
Cigarette smoking and pregnancy
Associated with higher incidence of low birth rate. Also arterial damage.
Fetal alcohol syndrome
Skin fold at corner of the eye, low nasal bridge, short nose, small head circumference, small eye opening, small mid face, thin upper lip. Basically small features of head.
Mothers 16 or younger
higher risk of eclampsia and preeclampsia and for delivery of low birth weight or nutritionally deficient infants.
Mothers 35 or older
At a greater risk for gestational diabetes or hypertension and for chromosomal aberration.
Chiari malformation
common cause of hydrocephalus. Herniation of cerebral tonsils blocks outflow of CSF. Cause papilledema.
WHAT IS A LOW BIRTH WEIGHT
less than 5.5 lbs.
Factors of infant survival
respiratory distress syndrome, low body fat, vulnerability to infections
Extreme low birth weigh
Less than 1,000 g
APGAR score
check of body functioning at birth. o, 1, or 2 assigned to heart rate, respiratory effort, muscle tone, skin color, and reflex irritability. measure at 1 and 5 minutes.
What does the APGAR score mean
Best is 10. A score below 7 means child needs help establishing breathing. below 4 is critical.
Body weight in infant
double it by 4 months, triple it by 1st year, and 1/5th adult weight by 24 months
Growth in infants
mostly in the limbs. Infantas grow 1 inch longer each month and at 24 months 1/2 adult height.
SIDS
leading cause of death in infants after congenital anomalies. Risk with poverty, young mothers, smoker, male babies, bottle fed, sleeping on stomach.
4 physiological states in the infants life
Quiet deep sleep, active sleep, alert, crying.
Infant’s daily cycles
develop during the first year
at birth the human brain is ____ of its adult weight
25%
When does myelination occur
rapid up to 4 years but continues after
Critical period
The first two years. There is a rapid increase in dendrite growth and sympases
Transient exuberance
The increase in connection in the brain
When does synaptic dentisty reach its maximum
2 years
When does synaptic pruning occur
at age 7
What determines the density of the cortical synpases
environmental encounters.
WHAT IS THE CRITICAL AGE
BIRTH TO 2 YEARS
Peak critical age
3-6 months
Plastic period
2 to 7-10 years
Visual maturity
10-15 years
what is the least developed sense at birth
vision
Hearing development
infants can distinguish there mothers voice almost immediately. They can discriminate similar sounds at 1 month. Hearing acuity develops for higher frequencies but poor localization.
Taste and smell development
fairly well developed at birth and reach peak at 1 year
Intermodal perception
The ability to associate one stimulus with t he input of another. Good by 3 months. i.e. know what objects create what sound.
Cross modal perception
Present at 1 month. The ability to use information from one sensory modality to imagine input from another.
Infant reflexes for survival
Breathing, cold, sucking, rooting
Babinksy reflex
toes go out and back when put fingers on bottom of foot
Moro
Startle reflex.
Palmar grasping
will hold onto finger
Stepping and swimming
when hold up will walk. when hold stomach will swim.
Age lifts head on stomach
3
Rolls over
5
Sits without support
8
Crawls
9
Stands holding on
10
Walks holding on
13
Walks well
14
walks backward
21
Walks up steps with help
22
Kicks ball
24
Can touch objects
3
grasps objects
5
grasps objects and put in mouth
8
Use thus and finger to pick up
9
what limits oculomotor control in infnats
sensory (afferent) defects in motor reflex arc (retina is not mature)
how long should you breast fed
recomended for 6 months but suggested for 2 years
Marasmus
sever malnutrition during first year that stops development and growth.
when is cognitive development rapid
during first year.
Piaget’s Model
Sensorimotor intelligence occurs from birth to 2 years. All stages are based on affordance of opportunities to learn.
Piaget substage 1
Intelligence functions in terms of senses and motor skills
piaget stubstage 2
More cognitive in terms of cause and effect thinking (6-9).
piaget substage 3
repeats actions to get desired results
piaget substage 4
goal directed behavior where results are anticipated despite any distraction
Piaget substage 5
Little scientist
piaget substage 6
more contemplative and reflective. pretend stage.
Object contancy
during first 2 years. Perceive boundaries and learn that an object stays the same size despite change in appearance when closer or further.
Object permanence
objects and people still exist even when they cannot be seen.
Categorizontal
infants greater than 6 months can categorize objects, speech.
Memory
Better than though. Good at non-language.
language development
born ready to learn language.
Parantese
high pitched baby talk. Helps with language acquisition
Language acquisition steps
receptive language, expressive language, reading acquisition, written.
Underextension
Toddlers use a word to refer to a narrow category. i.e. dog is there dog only
overextension
Overgeneralization of word to similar characteristic. All 4 legged animals are dogs.
Holophase
A single word to describe a complete though. I.e. pee pee
First words
13 months
growth spurt of words
18 months
First 2 word senstence
21 months
Multiword sentence
24 months
when do social smiles start
2 months
Stranger wariness
First noticeable by 6 months
Seperatetion anxiety
8-9 months and peaks at 14 months.
Social referencing
appears at 12 months where they will look at trusted individual for cues
Self awareness
2nd year. become more self conscious.
Secure attachment
an infant who desires to be close to caregiver but who is not afraid to explore
insecure attachment
very mixed. sign of neglect or abuse
Freud stages
Oral stage (birth-1year), anal stage (1-2).
Erikson stages
Trust vs. mistress (with to 1 year), autonomy vs. shame.
Pacific Acuity Cards
Must look at shape or compare the two. Testability of two figure forced choice good for children up to 18 months and up. Younger children better for single.
Acuity with PAT vs. cardiff
PAT is one line worse
What patient is PAT good for?
reduced vision (amblyopia). Fine on teller but awful on lea. This is in-between.
Teller card and amblyopia
Good to test difference in RE before patient knows lea symbols.
At what age should you use PAT
18 months or older
What to test those below 18 months
single vanishing optoype (cardiff).
What is PAT good for
Yields acuity measures closer to standard optotype tests than most commonly used refractive tests for preverbal children. Good for detecting and monitoring amblyopia at a younger age and assessment of vision in children with impairment.
VEP
The ultimate way to determine resolution capability at the level of the visual cortex in nonverbal patients. Demonstrate that infant acuity is much greater than we can observe.
When does VEP show 20/20 vision
around 6 months
Cons of VEP
must have the child’s attention.
Recognition acuity
By 2.5-3 years children can usually use lea symbols.
What to expect for 3 year olds w/out RE with lea
20/30
When 20/20 with lea
4-5 years
Contrast sensitivity in young
Most useful for kids with visual impairment.
When is the stimulus response curve and accuracy adult like?
3-4 months
Response to ____ lens is poor in infants
minus lenses
When are the motor pathways for eye movements and accommodation present?
At birth but they are dependent upon maturation of the sensory system for development.
What systems develop together
Sensory and motor
Accuracy of fixation at birth
Limited by foveal immaturity
What do infants use for vision
rough central fixation during the first 3 months of life.
What are the most mature eye movements at birth
saccades
what type of saccades do 1-2 month year olds use
they can only make small saccades
What type of saccades do 6-8 month olds use
One large single saccade.
Scanning in infants
Use same scan pattern as adults but they make smaller saccades and show longer fixation times
When does the cortical aspect of saccades develop
improves rapidly in the first few months of life and then continues on a slower trajectory.
Pursuit eye movement development
More affected by foveal development than saccades.
When can you see pursuits
1-4 weeks. At first pursuit velocity lags behind stimulus velocity and there is a large latency before initiation. The infant uses saccades to catch up to the stimulus.
Head movement in young
Will use head movement to supplement both saccades and pursuits. Early head control is poor so the oculomotor systems must do most of the work in very young infants
Accurate pursuit of moving object at 6 months is accomplished by
equal head and eye movements.
Pupillary reflex
response to light and accommodation are present at birth in full term and pre term infants.
Is anisocoria normal in infants?
Yes less than 1.5mm. Reduces overtime.
Pupil diameter in infants
highly variable
VOR in children
Infants show a much greater VOR than adults
OKN in infancy
Have a much weaker in nasal to temporal direction. Has asymmetry of monocular response. This should be gone by 6 month.
Who is persistent asymmetry of OKN seen in?
Children with unilateral deprivation of strabismus. It is not dx as some children with normal binocular visual input retain this asymmetry.
Newborns accommodation
Exhibit inaccurate accommodative response to varying stimulus demands. Can find some over accommodation and pseudo myopia.
Infants with hyperopia over 3-4D
show less likely to emmetropize.
Critical period for BV
First 12 month. Especially 3-9 months
Most neonates enter the worth with rough ___tropia
orthotropic and yoked eye movements
The development of normal binocular vision including accurate mergence eye movements depend on
foveal and cortical development
At birth the _____ of retinal cells is stable but the ____ of the retina will
number and type, area. Thus the primary retina changes post natal is the redistribution of retinal elements. Retinal periphery expands most rapidly.
Neonate Fovea
Foveal depression is immature at birth. By 1 week after birth there is a shallow foveal depression but the thick cones still lack outer segments and are only 1 cell deep in the fovea.
When does the fovea reach maturity
Between 15 and 45 months of age.
When can you see the FLR
6 months
Difference in neonates foveas
Cone density is lower. Photoreceptors are diferent
When is visual pathway myelinated
24 months
Neonate visual cortex has reduced ____ & ____
Disparity tuning, contrast sensitivity
What is the limiting factor for binocular function?
foveal and cortical immaturity
When are appropriate convergence and divergence responses present for binocular vision
Prest at 1 month and consistent at 2 months
Hirschberg test at birth
1 mm nasal.
At what age are the eyes aligned 100%
3-4 months
When is convergence to 10-15 cm seen?
3-4 months
When is convergence to adult (6-10) seen
6 months
When does true fusion occur
10-14 weeks
When can you see stereopsis in clinical settings
9-12 months
When will you see normal adult stereopsis
7-8 years. Adult level (20 arc seconds). Think it is normal at 5.
Critical period for susceptiblity
Time frame in which deprivation or abnormal experience can permanently alter the function of the neurological system.
Critical period for acuity
First year is most critical but periods as late as 7-9 can still change.
Critical period for steropsis
3-9 months but deprivation even after maturity can affect
_____ during critical period leads to very poor outcomes
constant strabismus
Most sever amblyopia
deprivational
Brain growth and Optometry
Brain growth at 2 years for language development. Visual spatial development in right at 4-5. No rolling E’s.
Fine motor during preschool
Do not develop as much as gross. Due to incomplete myelination and lack of full muscle control.
When do children connect numbers and counting
2 years
Giving a 3 year old vs. 5 year old directions
3 year old: needs specific instructions
5 year old: planning and goals.
building memory
ask specific questions and supplement the questions with additional information
when is right and left established
6 or 7
laterality on external object
7-12
Centration
Tendency to focus their analysis on one aspect of a situation or object to the exclusion of all other. EX: lions are not cats.
conservation
The inability to understand that an amount or quantity is unaffected by changes in its shape or placement
Irreversibility
inability to recognize that reversing a transformation brings about the same conditions that existed prior to the transformation.
Piaget’s preoperative thoughts
Concentration, conservation, irreversibility
When are preoperative thoughts understood
By 3 years but fragile
guided participation
A process in which the child turns through social interaction with a tutor.
Zone of proximal development
Difference between individuals development and what could be attained with a tutor.
Scaffold
To structure a child’s participation so they learn.
Fast Mapping
Process used to group essential meaning of new words by quickly connecting them to words and categories that are understood.
When does prevalence of myopia increase
About age 7.
Identity
The logic that a given substance remains the same no matter what change occurs. Concrete.
Reversability
The logic that something that has been changed can return to its original state
Reciprocity
A change in one dimension of an object can be compensated for a change in another.
Class inclusion
The idea that a particular object or person may belong to more than one class.
Evaluating cognitive growth in school
Achievement, aptitude, IQ
Acheivement
how much a person knowns in an area. I.e. midterm
aptitude test
potential rather than accomplishment
IQ
Mental age.
When are 2nd languages most easily learned
before age 10
