The document discusses the development of vision in children from birth through early childhood. It covers the maturation of anatomical structures like the retina, lens, and visual cortex. Key developmental milestones are discussed such as the development of visual acuity, contrast sensitivity, color vision, binocular vision, and refractive error. The critical period of visual development is noted to be the first few years of life when the visual system is most plastic. Parents are encouraged to provide a normal visual environment to support healthy visual maturation in children.

1. You will see what’s
your mind knows.

2. DEVELOPMENT OF
VISION IN CHILDREN
Moderator: Dr.Sanjeev Bhattarai
Presenter: Aanand Kr. Shah and Aaratee Jha
3rd year optometry, IOM

3. PRESENTATION LAYOUT
 Introduction
 Development of anatomical structures
 Development of visual attributes
 Visual development milestones
 Expected visual performances
 Parents role in visual development
 Abnormalities in visual development
 Risk factors and signs of abnormal visual
problem
 Management and available treatment option
 Summary

4. INTRODUCTION
 Visual system is the most complex sensory
system in the human.
 Components from eye to the neural circuits.
 Not fully developed at birth.
 Matures over the 1st few years of life.

5.  Healthy maturation requires exposure to a
normal visual environment.
 Good vision is developed through a learned
process of looking, touching and exploring.
 Pearl point:
Anatomical structures needed
for sight is present in infants
but they have not learned to
use them.

6. Development of vision in
children completes mainly in 3
steps:
Development of anatomical
structures
Oculomotor development
Physiological development

7. Further its includes:
Development of refractive
errors
Development of grating
acuity
Development of other visual
attributes

8. Development of anatomical
structures
 Axial length:16-17mm at birth (70% of adult
size)
 Orbital volume:10.3-22.3mm³ (50% of adult)
 Cornea flat at birth, becomes steeper as age
increases.
Worthy point:The retinal images are smaller
compared to adult due to shorter
distance from the retina to the
cornea of the infant’s eye.

9.  Conjunctiva in children is thicker and tougher.
 Average lens power: 45D during infancy (loses
about 20D of power by 6 yrs).
 Lens accommodation occurs at 1 month of age
(14-16D at birth).
 Muscle insertion and their relationship to the
limbus and equator changes dramatically
within 1st yr of life.

10.  AC Angle is shallow, iris and ciliary processes
are present posteriorly.
 Differentiation of fovea occurs relatively late
than peripheral parts of retina (incomplete
until 4 months after birth).
 Macula is least developed at birth (at 8 months
postnatal).

11.  Optic nerve head attains full size after birth.
 Myelination of visual pathway uncompleted
until 2yrs of age.
 Notes:
i. Foveal reflex is present by 37 weeks of
gestation.
ii. Pupillary response is positive by 31
weeks of gestation.

12.  Peripheral retinal development:
 Development of temporal retinal region
complete between 8 to 9 months of gestation.
 Peripheral retina in other regions of globe
continue to develop after birth.
 Zone between ora serrata and equator
enlarges in size until about 2 yrs of age.

13.  Retinal vascularization:
 Proceed from centre to periphery.
 Mature pattern of vascularization is present by
3 months after birth.
 Supplied by central retinal artery and short
posterior ciliary artery.

14.  Visual cortex development:
 Information from 2 eyes is 1st combined in
striate cortex.
 Most neurons in visual cortex are binocular
(i.e. receiving inputs from both eyes).
 However, most neurons don’t receive equal
input from 2 eyes hence one eye tend to
dominate a given cortical cell called as ocular
dominance.

15.  Cells in categories 1 and 7 are monocular i.e.
Category 1 cells receive input from only the
contralateral eye whereas category 7 cells
receive input from only the ipsilateral eye.
 Neurons in category 4 are binocular and
receive input from both eyes.
 Cells in remaining categories are also
binocular but dominated by one of the eyes.

16.  Neurons in category 2 and 3 are dominated by
the contralateral eye and those in category 5
and 6 are dominated by ipsilateral eye.

17.  David Hubel and Torston Wiesel
experiment on Kitten:
 They sutured one of a kitten eye lids closed at
birth and recorded from striate cortex after
animal has fully matured.
 Striate cortex of monocularly deprived animal
is very different from that of a normal animal.

19.  Virtually all cells are monocular and responsive
only to the nondeprived eye.
Conclusion:
 It is necessary for both eyes to provide input for
the normal development of striate cortex
binocular cells.
Additional point:When the eye of a 7yrs old cat
is closed for 1 yr, monocular
deprivation has no effect, there
is a normal complement of
cortical neuron.

20.  Hubel and Wiesel work suggest that:
 During critical period, the two eyes compete
with each other to dominate cortical neurons.
 If both eyes have equal retinal image then
most of cortical neurons becomes binocular.
 When one eye wins out in competition results
ocular dominance.

21.  Hebb’s synapse model:
 Synaptic connectivity in the cortex is
strengthened by neural activity.
 Geniculate neuron with input from the
nondeprived eye will stimulate a cortical cell
more strongly than a geniculate neuron from
the deprived eye.
 There is a strengthening of synapses for the
nondeprived eye relative to the deprived eye.

22. Fig: Hebb’s synapse model
NOTE:
 Monocular deprivation has a more
pronounced effect on the ventral pathway than
the dorsal pathway (Schroder et al.,2002).

23.  Critical period:
 The period during which the visual system can
be influenced by environmental manipulation.
 Most sensitive to environmental manipulation
during the 1st two yrs of life.
 The human critical period is over by
approximately 7 to 9 yrs of age (Vaegan and
Taylor, 1980).

24.  Developmental plasticity:
 Visual system is plastic early in life, it becomes
hard wired later in life.
 The visual system is flexible to change from
birth to 12 yrs of life.
Bilateral visual deprivation can be
caused by congenital cataract,
corneal opacity, bilateral
congenital ptosis and media
opacities.

25. Development of refractive
errors
 Typical healthy human are born with or
develop a slight amount of hyperopia (less
than 2.50D) during the 1st year of life (Slataper,
1950; Dobson et al.,1981).
 Degree of hyperopia tends to decrease
throughout childhood and shouldn’t normally
be corrected (Howland and Sayles, 1987).
 Emmetropization is completed by 6 yrs of age.

26.  The correction of refractive error in infants and
toddlers is controversial because lenses could
be potentially interfere with emmetropization.
 The prescription of minus lenses for myopia
lead to near defocus thereby promoting the
development of additional amount of myopia.
 Spectacle correction of clinically significant
amount of hyperopia in infants doesn’t
interfere with emmetropization.

27. Refractive errors early in life
Age (month) Average spherical equivalent
(D)
Percent with > 1D
Astigmatism
1 +2.20 4
1.5 +2.08 6
2.5 +2.44 19
4 +2.03 21
6 +1.79 16
9 +1.32 16
12 +1.57 11
18 +1.23 9
24 +1.19 6
30 +1.25 9
36 +1.00 5
48 +1.13 4

28.  Animal studies on monkeys, cats and
chickens have shown that:
 Eyes in which the retina is allowed to receive
light but no form vision tends to become highly
myopic (i.e. the disruption of normal visual
experience leads to a breakdown in the
emmetropisation).

29.  Such high myopia can be reversed if normal
viewing conditions are resumed, as long as
this occurs within a critical period of
development.
 Human infants born with ocular pathology
such as cataract tends to develop high myopia
and have a much wider spread of refractive
errors.

30.  More Time Outdoors May Reduce Kids'
Risk of Nearsightedness:
 Those children who spent 3-7 hrs/week, their risk
of being nearsighted dropped by about 2%.
David Turbert (Aug. 28, 2014)
There is some evidence from recent studies in US
and Australia that the amount of time school aged
children spend outdoors in natural light may
have some impact in whether they develop mild
myopia.

31.  Natural light may be essential for normal eye
development in kids.
 Rate of eye growth varies in relation to
exposure to the daylight.

32. Development of grating
acuity
 Resolution acuity of 1 month old infant as
measured behaviorally with spatial grating is in
the order of 20/600.
 Adult levels are reached by about 3 to 5 yrs of
age (Teller, 1997).
 Procedures used to assess grating acuity in
infants include:
A. Optokinetic nystagmus (OKN)
B. Preferential looking
C. Visually evoked potential

33. A. Optokinetic nystagmus:
 A moving grating produces nystagmus.
 Consists of slow following movement (smooth
pursuit) followed by fast compensating eye
movements (saccade).
 Depends upon the ability to resolve the
gratings.

34.  Used to assess visual capabilities in
uncooperative children including infants,
malingers and mentally retarded.

35.  Preferential looking:
 When given a choice between patterned and
non patterned stimulus infants prefer to view
the patterned stimulus.
 Used to determine infants grating acuity.
 Both patterned and non patterned stimuli have
same average luminance.

36.  If the examiner is required to guess which side
the pattern is present, the procedure is
referred as forced choice preferential looking
(FPL).
 Alternating of preferential looking involves the
use of Teller grating acuity cards.

37.  Studies using Teller’s acuity cards
reveals:
 Healthy infants of 1 month have acuities of
about 20/600.
 Resolution acuity improves rapidly during 1 yrs
of life.
 1 year children manifesting acuities of about
20/100.

38.  Visually evoked potential:
 FPL suggests that adult level of resolution
acuity are reached between 3 and 5 yrs of age
whereas VEP’S show adult levels at 6 to 8
months.
 The different result obtained with FPL and
VEPs may be related to the greater cognitive
demands associated with FPL (Dobson and
Teller, 1978).

39. techniqu
es
birth 2
months
4
months
6
months
1 year Age for
20/20
Optokinet
ic
Nystagm
us (OKN)
20/400 20/400 20/200 20/100 20/60 20-30
months
Forced
preferenti
al looking
(FPL)
20/400 20/400 20/200 20/150 20/50 18-24
months
Visually
evoked
potential
(VEP)
20/800 20/150 20/60 20/40 20/20 6-12
months

40.  Causes of decreased visual acuity in
the infants:
I. Foveal cone immaturities: cone attain adult
density and size of cones by 4 yrs of age.
II. Cortical immaturities
III. Incomplete myelination of the optic
pathways: complete myelination of the optic
nerve and optic pathway takes greater than 2
yrs.

41. Development of visual
attributes
1. Contrast sensitivity:
 CS for 1 month old infants doesn’t have band
pass form suggesting that lateral
interconnections within retina have not fully
developed in infants.
 As infants mature, CSF assumes a band pass
form and shifts to the right and upward
indicating increased CS for most spatial
frequencies and improved visual acuity
(Movshon and Kiorpes, 1988).

42.  Peak of the CSF is at adult location at about 4
yrs and overall function is adult like by 9 yrs
(Adams and Courage, 2002).

43. 2. Vernier acuity:
 Form of hyper acuity
 Matures rapidly during the 1st year.
 Reaching adult level at the age of 6-8 yrs.
 Depends on the cortical processing

44. time Visual acuity Contrast
sensitivity
Birth ≈6/300 unknown
3
months
6/90 to 6/60 ≈6/60
1 year ≈6/24 ≈6/9
2years ≈6/12 to 6/9 ≈6/6
3 years ≈6/9 to 6/6 ≈6/6

45. Physiological development
 Binocular vision:
 Establish during the 1st few year of life.
 Binocular cortical function 1st emerges at 3-5
months.
 BSV is established by the age of 6 months.

46. Binocular
process
Time
Convergence 1 month
Conjugate
fixation reflex
5-6 weeks
Saccades 4 months
Conjugate
movement
6 months
Fusional 6-8 months

48.  Anatomical cause for the absence of
BSV at birth:
 Retina and fovea aren’t fully developed so
poor visual perception.
 Ciliary muscle not fully developed until 3 yrs.
 Medial rectus is more developed than other
muscle.

49. Age Physiological
functions
Birth Compensatory reflex
2-3 months Orientation reflex,
refixation reflex,
pupillary reflex and
vergence reflex
2-3 years Accommodation reflex
and fusional vergence

50.  Stereopsis:
 Rapid onset between 3 and 6 months.
 Sensitivity to crossed disparities appears 3
weeks earlier than uncrossed disparities.
 In 1-3 months, infants don’t alternately
suppress each eye but superimpose images.
 Begins to show binocular fusion at 3 months.
 Reaching 1 minutes of arc by 6 months.

51.  Color vision:
 Can match colors by 2 years.
 Infants (younger than 3 months) are less
sensitive to blue than adults.
 Infants preferred red, green, and yellow
pattern.
 Color vision close to adults by 2-3 months.

52.  Newborns can perceive few colors but they
are able to see the full range of colors by 3-4
months (Kellman, 1998).

53.  Light sensitivity:
 Infants have the greatest sensitivity to
intermediate wavelengths (yellow/green) and
less to short (blue/violet) or long (red/orange)
wavelengths.

54.  Binocular motion processing:
 Magnocellular neurons appear earlier in
development than parvocellular neurons.
 Magnocellular pathway is biased at birth so as
to respond preferentially to target that move in
temporal to nasal direction in visual field.
 The nasal preferences is due to biases in the
visual not motor pathway.

55.  Vergence:
 Vergence becomes remarkably accurate by
the age of 6 months.
 Vestibulo-ocular reflex is present at birth which
stabilizes the eye when the head assumes
different static position or the body turns.

56.  Temporal vision:
 Critical Flicker Fusion Frequency(CFF) is about
40Hz at the age of 1 month.
 Reaches adult level at about 55Hz by 3 months.
 Retinal and cortical immaturities that slow the
development of grating and vernier acuity
apparently have little effects on the
maturation of temporal resolution.

58.  Scotopic sensitivity:
 Adult like at the age of 1 months.
 The absolute sensitivity of the scotopic system
reaches adult levels by about 6 months of age.
Note:
 Absolute sensitivity refers to the sensitivity
for a stimulus of 507nm presented under
conditions that maximize scotopic
sensitivity.

59.  Face processing:
 Capable of discriminating between two human
faces by 6 months.
 The ability to distinguish among faces become
more specialized as an infant matures.

60.  Accommodation:
 Most infants can focus accurately by 2 -3
months of age.
 Adult like by about 4 months.
 Rate of development of accommodation is
varied among infants.
 Rate of accommodation is affected by the
presence of significant hyperopia.

61.  Field of vision:
 Peripheral vision is 15° lateral of central vision
at about 2 months.
 It becomes 35° lateral of central vision at
about 7 months.

62.  Tracking and object interception:
period Tracking and interception
40-52 weeks Can track a 180degree of arc
5-6 years Can track objects in horizontal plane
8-9 years Can track balls that travel in arc

63. Oculomotor development
 Saccadic eye movement:
 Present by 1-3 months.
 Voluntary saccades are completed at 12 yrs of
age.
 Latency of saccades decreases with age of
children and doesn’t depend on the direction
of saccades.

64.  Smooth pursuits:
 Slow conjugate movement
 Develops at 2 months of age.
 Note:
I. Binocular coordination of pursuit is
abnormal in children with vergence
deficits and worse in strabismic children.
II. Binocular vision plays an important role
in improving binocular coordination of
pursuit.

65. Extra ocular functions
maturation
Conjugate horizontal gaze –
birth
Visual fixation – birth
Ocular alignment – 1month
Fixation reflex – 2 months
Conjugate verticle gaze – 2
months
Visual following – 3 months
Accommodation – 4 months
Fusional convergence – 6
months

66. Think about:
Convergence become more
fully developed by about age
7, this is one reason any
problem a child has with
focusing or eye alignment
should be treated before that
age.

67. Visual development
milestones
Visual development Approximate time
Pupillary light reaction 30 weeks of
gestation
Saccades well developed 1-3 months
Ocular alignment stabilized 1 months
Smooth pursuit well developed 6-8 weeks
Blink response to visual threat 2-5 months
Fixation well developed 2 months
Accommodation appropriate to target 4 months
Foveal maturation 4 months
Stereopsis well developed 3-7 months
Contrast sensitivity function well developed 7 months
Optic nerve complete myelination 7 months to 2 years

68. Expected visual
performances
 Birth to 6 weeks of age:
 Stares at surrounding when awake
 Momentarily holds gaze on bright light or
bright object
 Blinks at camera flash
 Eyes and head move together

69.  8 weeks to 24 weeks:
 Eyes begin to move more widely with less
head movement.
 Eye begins to follow moving objects or people
(8 to 12 weeks).
 Watches parent’s face when being talked to
(10-12weeks).
 Begins to watch own hands (12-16 weeks).

70.  Looks at hands, food, bottle (18-24 weeks).
 Looks and watches for more distance objects
(20-28 weeks).

71.  30 weeks to 48 weeks:
 May turn eyes inward while inspecting hands
or toys (28-32 weeks).
 Eyes are more mobile and moves with little
head movement (30-36 weeks).
 Watches activities around for longer periods of
time (30-36 weeks).
 Looks for toys when drops (32-38 weeks).

72.  Visually inspects toys she/he can hold (38-40
weeks).
 Creeps after favorite toy when
seen (40-44 weeks).
 Sweeps eyes around room to see
what’s happening (44-48 weeks).
 Visually responds to smiles and
voice of others (40-48 weeks).

73.  12 months to 18 months:
 Visually steering hand activity (12-14 months).
 Visually interested in simple pictures
(14-16 weeks).
 Often holds objects very close to
eyes to inspect (14-18 months).

74.  Points to objects or people using words “look”
or “see” (14-18 months).
 Looks for and identifies pictures in books (16-
18 months).

75.  24 months to 36 months:
 Smiles, facial brightening when views favorite
objects and people (20-24 months).
 Likes to watch movement of wheels,
etc. (24-28 months).
 watches and imitates other children
(30-36 months).
 Able to keep coloring on the paper
(34-38 months).

76.  40 months to 48 months:
 Brings head and eyes close to page book
while inspecting (40 44 months).
 Draws and names circle and cross
on paper (40-44 months).
 Can close eyes on request and may
be able to wink one eye
(46-50 months).

77.  4 years to 5 years:
 Copies simple forms and some letters.
 Can place small objects in small openings.
 Visually alert and observant of
surroundings.
 Tells about places, objects or
people seen elsewhere.

78.  School age children:
 Clear near vision for reading and
comfortably viewing close objects.
 Binocular vision
 Eye movement skills in order to
accurately aims the eyes.
 Focusing ability to keep both eyes
clearly focused at various
distances.

79.  Peripheral vision to be aware of objects
located out of direct view.
 Eye hand coordination to accurately use the
eyes and hand together.
 Eye-body coordination to visually guide body
movements.

80. Attention!!!
 Your baby should able to:
1. Follow an object with his/her eye by 1 month.
2. Bring his/her hand together by 2 months.
3. Turn his/her eyes together to focus at near
objects by 4 months.
4. Roll over independently by 5 months.

81. 5. Sit up without support by 8 months.
6. Creep and crawl by 9 months.
Note:
I. Creeping on all four limbs is very
important for developing coordination of
both the eye and the body.
II. Schedule your baby 1st eye exam around
6 months of age.