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39 Cards in this Set

  • Front
  • Back
Visual acuity is a
Measure of sensitivity of spatial discrimination
Acuity increases by about
1 cycle per degree per month until 20 months of age
The critical period for normal visual development is
Before 6-8 months of age
The limitation to early acuity is the
Nervous system’s ability to process the image
VA obtained with VEP is similar to adults by
6-8 months of age
Loss of sensitivity at low spatial frequencies indicates
The working of lateral inhibition (noticed at 2 mo)
The high frequency cut off changes from
2cpd at 2mo to 20cpd at 10mo
The lowest sensitivity to low spatial frequency is seen
Between ages 8-15
Avg refractive error in premature infants is
+0.50D SD 2.80D
Ave refractive error in full-term infants is
+2.00D SD 2.00D
1yr old RE =
+1.00 SD 1.1D
3yr old RE =
+0.95 SD 1.00
By 5 mo of age infants develop an
Adult sensitivity curve to different wavelengths of light
Brunescence of the lens causes the absorbance of
Short (blue) wavelengths of light
Accommodation if well developed by
4 mo of age
Lid closure in response to bright light is seen at
30 weeks gestation
The blink response to visual threat is seen at
2-5 mo of age
Infants have 1 min of stereopsis (60sec) by
21 weeks (~5 mo)
Saccades are present at birth and fully developed by
4-5 mo of age (step saccades present before 4 mo)
Infants use smooth pursuits for low velocities by
2 mo of age
OKN is seen at birth
At 5-6 wks of age tracking is completed by
Saccadic movements, not pursuits
OKN is
- smooth pursuit with a saccadic refixation in the opposite direction
Monocular OKN is observed at
3 months of age
An asymmetric OKN is seen with
Temporal to nasal mvnts of a stimulus (seen under 3 mo)
The vestibular sense isn’t fully developed until
4-5 years of age (child uses vision to stand upright)
Conjugate horizontal gaze is well developed at
Conjugate vertical gaze is well developed at
2 mo of age
Papillary light reaction is present at
31 wks (~6mo)
The critical period for the development of ocular dominance columns is
Between 6-8mo and 2.5 yrs in humans; 6wks in monkeys; 1-3 mo in kittens
Deprivation experiments show
No effect on the retina; Shrinkage of cells in all layers of the LGN; visual cortex is severely affected; alteration of ocular dominance columns occurs
Pattern deprivation causes more disturbance of
Binocularity than light deprivation
The number of binocular cells decreases from
80% to 20% in a stabismic animal
Contrast sensitivity decreased with age
Important for contact lens wearers
Macular degeneration and nuclear sclerosis cause
A loss in discrimination of the blue end of the spectrum
Convergence ability stays the same or better with age
Because accommodative convergence can be used
The time to rod cone break
Remains constant as one ages
Senile miosis accounts for a
7 cycle per second decrease in CFF by age 40yrs
The most widespread of the psychoses is