VD Exam 2 Flashcards
REFRACTIVE ERROR IN CHILDREN: Axial length in full-term newborns vs. adults
FT newborns: 16mm (90D)
Adults: 24mm (60D)
REFRACTIVE ERROR IN CHILDREN: Limits of emmetropization
+0.50 to +1.00 D of hyperopia with a SD of +/- 1.00D
REFRACTIVE ERROR IN CHILDREN: When does the greatest degree of emmetropization occur?
Within the first 2 years of life
REFRACTIVE ERROR IN CHILDREN: When does myopia increase and what are the incidences?
Myopia increases in prevalence during SCHOOL YEARS
6% of 6-year-olds are myopic
15% of 15-year-olds are myopic
Although 80-85% remain hyperopic (+0.50 to +3.00D)
REFRACTIVE ERROR IN CHILDREN: What is considered an extreme newborn refractive error
> +5.00 or -4.50 D
emmetropization usually does not occur
REFRACTIVE ERROR IN CHILDREN: How does the compensation range of humans compare to that of chicken and monkey models?
Chickens: -10 to +15D
Monkeys: -2D to +8D
Humans: +1 to +5D (estimate)
REFRACTIVE ERROR IN CHILDREN: How many grams is a low birth weight (LBW), very low (VLBW), and extremely low (ELBW) baby?
LBW: 2500g
VLBW: 1500g
ELBW: <1000g
REFRACTIVE ERROR IN CHILDREN: Retinopathy of Prematurity (ROP) affects infants born around what week and weighing how much?
Before 31 weeks of gestation
Weighing 2-3/4 pounds (1250 grams)
REFRACTIVE ERROR IN CHILDREN: What is the average refractive error of premature infants at birth?
-0.50D (S.D. +/- 2.80)
REFRACTIVE ERROR IN CHILDREN: What is the average refractive error of FULL term infants at birth?
+2.00D (S.D. +/- 2.00D)
REFRACTIVE ERROR IN CHILDREN: What is the axial length of FULL term newborns?
16 mm
REFRACTIVE ERROR IN CHILDREN: Average refractive error of 1-year-old child
+ 1.00D (S.D. +/- 1.10D)
REFRACTIVE ERROR IN CHILDREN: Average error of 3-year-old child
+0.95D (S.D. +/- 1.00D)
REFRACTIVE ERROR IN CHILDREN: Spectrum age in months from 1 to 48 and spherical equivalent (mean SD)
First month: 2.20 (SD 1.60)
48th month: 1.13 (SD 0.85)
*preschool age (mean refractive error +0.50 to +1.00D) (SD +/- 1.00)
REFRACTIVE ERROR IN CHILDREN: When does the refractive state of children reach an emmetropic plateu?
5 to 7 years of age
REFRACTIVE ERROR IN CHILDREN: Compare age with shape of refractive error distribution curve (at birth, preschool years, age 10-11, beyond 11)
At birth: bell shaped
Preschool years: Leptokurtotic- steeper towards hyperopia
Age 10-11: Leptokurtotic - symmetrical
Beyond 11: Leptokurtotic - skewed towards myopia
REFRACTIVE ERROR IN CHILDREN: What are the three different degrees of myopia and their corresponding spherical equivalents?
Low myopia: < -3.00D
Moderate: -3.00 to -5.75D
High: > -6.00D
REFRACTIVE ERROR IN CHILDREN: What is the spherical equivalent for high hyperopia?
> +5.00D
often associated with congenital or early onset anomalies
REFRACTIVE ERROR IN CHILDREN: Astigmatism decreases rapidly over the first ___ years of life
2
REFRACTIVE ERROR IN CHILDREN: At 6 months vs. 2 years, what is the level of astigmatism for children?
6 months: mean of 2.00 DC (ATR)
2 years: reduced to 0.50 DC
REFRACTIVE ERROR IN CHILDREN: Age and mean astigmatism (astigmatic error)
6 months: 2.00 to 2.50 DC
18 months: 1.00 DC
24 months: 0.50 DC
REFRACTIVE ERROR IN CHILDREN: At around what age do the ATR and WTR slopes intersect (age = x axis, proportion of ATR and WTR = y axis)
54 months (mostly ATR before, but ATR decreases)
REFRACTIVE ERROR IN CHILDREN: By what age does WTR astigmatism become predominant among child popularions?
By 5.5 years of age, WTR predominant (up to 3.5 years it was ATR)
REFRACTIVE ERROR IN CHILDREN: When does astigmatism become adult level?
By 5 years
REFRACTIVE ERROR IN CHILDREN: By school age, what is the prevalence of significant astigmatism?
Between 2-4% only (school age = 5 to 7 years)
DEVELOPMENT OF COLOR VISION IN CHILDREN: What is the difference in spectral sensitivity between 1 month old infants and adults?
1 month old infants have 1 log unit less spectral sensitivity in the short wavelengths than adults (approx. 80x less sensitive)
DEVELOPMENT OF COLOR VISION IN CHILDREN: What is the difference in spectral sensitivity between 3-month-old infants and adults?
3 month olds are about 15 times less sensitive than adults
DEVELOPMENT OF COLOR VISION IN CHILDREN: Rod responses from peripheral retina reach 50% adult values by what age?
3 months
DEVELOPMENT OF COLOR VISION IN CHILDREN: Rod responses close to the fovea reach 50% of adults levels by what age
5 months
DEVELOPMENT OF COLOR VISION IN CHILDREN: Is there any difference in photopic spectral sensitivity between infants 2,3 and 5 months old?
NO!
DEVELOPMENT OF COLOR VISION IN CHILDREN: By what age can infants discriminate between red, yellow, green, and blue from gray?
3 months
DEVELOPMENT OF COLOR VISION IN CHILDREN: For 3 WEEK OLD infants, which color vision tests indicate discrimination not entirely driven by intensity differences?
645nm and 547nm surround
DEVELOPMENT OF COLOR VISION IN CHILDREN: By what age is there evidence that all test wavelengths can be discriminated from the surround largely independent of relative intensities?
7 weeks
DEVELOPMENT OF COLOR VISION IN CHILDREN: By what age is there AT LEAST SOME ABILITY to discriminate among chromatic stimuli across most of the visible spectrum
2-3 months (normal rod + cone functioning)
DEVELOPMENT OF COLOR VISION IN CHILDREN: At which age is the INFANT SPECTRAL SENSITIVITY CURVE closely similar to adult curves?
5 months
DEVELOPMENT OF COLOR VISION IN CHILDREN: The form (shape) of the scotopic sensitivity function is adult-like at what age?
1 month
but REACHES adult levels only around 4-7 months of age ~closer to 6
DEVELOPMENT OF COLOR VISION IN CHILDREN: What is the absolute sensitivity of the scotopic system?
The sensitivity for a stimulus of 507nm presented under conditions that maximize scotopic sensitivity
DEVELOPMENT OF COLOR VISION IN CHILDREN: Absolute sensitivity of the scotopic system reaches adult levels by:
around 6 months
DEVELOPMENT OF COLOR VISION IN CHILDREN: Newborns can discriminate only between red and achromatic stimuli until what age?
around 3 months
DEVELOPMENT OF COLOR VISION IN CHILDREN: Photopic sensitivity curve reaches adult levels at what age (according to VEP studies)?
!!!!!NEWBORN!!!!!
DEVELOPMENT OF OCULOMOTOR SYSTEMS: By 6 months, what percent of infants make a series of saccades rather than one larger saccade?
30%
DEVELOPMENT OF OCULOMOTOR SYSTEMS: Infants make a series of small saccades rather than smooth pursuits when following a moving target until what age?
8 weeks
DEVELOPMENT OF OCULOMOTOR SYSTEMS: Normal pursuit gain (eye velocity = target velocity) is reached by what age?
4 months
DEVELOPMENT OF OCULOMOTOR SYSTEMS: By what age do all eye movements typically reach adult levels?
6 months
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: Tonic accommodation
Trend: decreasing tonic accommodation occurs with age
Adult: 0.5D
Infants 1.59D to 0.50D (3 to 12 months)
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: Proximally induced accommodation
Infants respond well to near target
may be pre-programmed
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: Convergent accommodation
Synkinetic relationship between accommodation and convergence by 2-3 months
Accommodation develops earlier than vergence
(TWO - “syn”… months)
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: When does a considerable amount of improvement in ability to accommodate to distant targets occur?
Between birth to 3 months
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: At what age is accommodation present, but not accurate (for early development)
3 months
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: By what age is accommodation developed to adult levels?
4 months
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: When can infants start making vergence eye movements?
Within first few weeks after birth (are unstable and inaccurate/cannot be initiated based on image disparity alone)
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: By what age can infants make consistent divergence eye movements?
1 month
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: By what age can infants make consistent convergence eye movements (accommodation and convergence become linked?)
after 2 months
DEVELOPMENT OF ACCOMMODATION AND VERGENCE: By what age do vergence eye movements reach adult levels?
by 6 months
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Do not perceive binocular depth
Newborn babies
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Sudden onset of stereopsis
3-5 months
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Adult level of stereopsis following rapid development of stereopsis
4-6 months (adult levels of stereopsis)
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: 100% of infants have stereopsis
7 months
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: stereoacuity reaches adult level of 1 minute of arc
24 months
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: mean age fusion is present
12.8 weeks
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: onset of fusion, correlates with the development of stereopsis
3-5 months
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Various tests for sensory fusion and stereoopsis
LANG FRISBY Random dot E Vectograms Titmus House Fly Randot Keystone Visual Skills Cards
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Age LANG stereo test is used
6 months - 4 years
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: age FRISBY test plates are used
FCPL method for children 13 months or older
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Age Random Dot E test is used
3 years and older
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Age Vectograms are used
3 years and older
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Age Titmus house fly test is used
3 years and older
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Age Randot test is used
4 years and older
Worth 4 dot - sensory fusion
DEVELOPMENT OF BINOCULAR VISION AND STEREOPSIS: Age Keystone Visual Skills Cards are used
4 years and older
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Global motion processing reaches adult levels at about what age?
14 years
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Speed discrimination for fast stimuli reaches adult levels at about what age?
11 years
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Speed discrimination for SLOW stimuli is not fully matured
not fully matured even at 11 years of age
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Cells in the LGN respond to higher temporal frequencies than ___?
60+ Hz
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: In infants, CFF reach adult levels by what age?
2-4 months (so it reaches 55Hz within 2-4 months)
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: What is the critical flicker frequency (CFF) at 1 month of age? 3 months of age?
1 month: 40 Hz
3 months: 55 Hz
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Form vision in infants at what age allows them to discriminate faces?
6 months
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Will a 4-year-old present with part of an object be able to perceive the full form?
NO!
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: At what age can infants disriminate betwen 2 human faces and 2 monkey faces
6 months of age
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: In comparison to younger infants, how well do older infants (9 months old) and adults discriminated between 2 monkey faces?
Decreased
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: When does light sensitivity develop (lid closure in response to bright light) and pupillary reflex develop?
LID CLOSURE: 30 weeks gestation
PUPILLARY REFLEX: 32 weeks gestation (28-35 week range)
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Blink response to visual threat
2-5 months after birth
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Visual field development time frame and level of development
Between birth and 2 months: very little development
2-8 months: rapid development (then slows again)
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Binocular upper VF (reaches adult levels) by
12 months
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Horizontal and inferior fields by
15 months
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Monocular fields reach adult levels by
17 months
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: what is the visible spectrum for humans?
400-700nm
DEVELOPMENT OF MOTION, TEMPORAL VISION, OTHERS: Spectral Transmission of the ocular components of the eye
RETINA: > 1500nm: 0% to retina 900nm: 90% to retina 770nm: 94% to retina 770-400nm: 100% to retina 400-320nm: age (cataract) <290: 0% to retina
CORNEA:
Absorption: >300 to <290nm
Transmission: 315-3000nm
AQUEOUS:
Absorption: very little
LENS:
Absorption: >2500nm, <320-400nm, depending on age
Transmission: 1000-2000nm with some absorption bands
VITREOUS:
Absorption: 400-1000 (100%), >1600nm, 270-320nm
Transmission: 270-1600nm
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: monkey vs. human visual system maturation
Monkeys visual system is very mature at birth compared to humans
Monkeys at birth: comparable to 3-week old human infant
Monkeys acuity develops 3x faster than humans
Contrast grating perception 40-50cpd
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Ocular dominance category cells and corresponding input
Cells in categories 1 & 7: monocular
Category 1 cells: input from contralateral eye
Category 7 cells: input from ipsilateral eye
Category 4 cells: binocular with equal innervation
Category 2,3,5,6: binocular with dominance by one of the eyes (2,3 contralateral, 5,6 ipsilateral)
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: What happens if the right eye of a kitten is closed for the first 5 weeks of life?
the cortex cells are primarily responsive to stimulation of the non-deprived left eye
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: It is probably best to consider prescribing lenses for young, school-age children if astigmatism shows ___
no signs of abating and is at least 2.00 D
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Strabismic amblyopia spatial distortion and uncertainty
Distortion up to 25 minutes
Range of uncertainty about 25-30 minutes on either side
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Strabismic amblyopia fixations
Fixations usually eccentric (nasal) and unsteady
Show large drifts as much as 5 degrees (tremor 60 Hz similar to normal)
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Congenital cataracts must be removed by what age
3 months (if not, will cause abnormal development of visual system)
VA WILL NOT BE BETTER THAN 20/60 if corrected later
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: If the cataract is treated by 3 months of age, what can be the expected VA
20/60 or better
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Traumatic Cataract: the amount of vision loss and age of onset
Traumatic cataract. in first 3 years of life - some vision loss
A traumatic cataract at a later age - less vision loss
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Human critical period
7-9 years
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Human most sensitive period of visual development
6-8 months to 2 years
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Critical periods of monkeys
first 6 weeks of life
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Critical period of kittens
1-3 months
EFFECTS OF EARLY ENVIRONMENTAL RESTRICTIONS: Hebbian Model of Synaptic Refinement
If both eyes have equivalent retinal images, then most of the cortical neurons become BINOCULAR
When one eye is deprived: because a LGN with input from the nondeprived eye will stimulate a cortical cell more strongly than a geniculate cell form the deprived eye, there is a strengthening of synapses for the nondeprived eye relative to the deprived eye