The Human Eye

Intra uterine The eyelids are not have fully separated; The pupil is not constrict or dilate; the aqueous

drainage system may not be fully functional. The iris lacks pigment. The choroid lacks pigment. Retinal blood vessels are immature. Optic nerve fibers may not be myelinized; There is still a pupillary membrane and/or a hyaloid

system.

Lack of ability to control light entering the eye; visual system is not ready to function.

At birth Infants are born with a complete visual system, but not

fully developed.

From birth to maturity The size eye increases to three times of that at birth, Most of this growth is complete by age 3 years One third of the eye's diameter growth is in the first year

of life.

At birth: The irises of infants:

The iris lacks pigment and may have a gray or bluish appearance; natural color develops as pigment forms.

The eyes' pupils: are not able to dilate fully yet.

The curvature of the lens: is nearly spherical not oval. The retina: (especially the macula) is not fully developed. The infant: is moderately farsighted and has some degree of

astigmatism.

The newborn has poor fixation ability, a very limited ability to discriminate color, limited visual fields,

By 1 month:

The infant can follow a slowly moving black and white

target intermittently to midline May also intermittently follow faces (usually with the

eyes and head both moving together). He/She will blink at a light flash,

There is a preference for black and white designs.

By 2 months:

Brief fixation occurs sporadically, ocular movements are still uncoordinated

The infant follows vertical movements better than horizontal Begins to be aware of colors (primarily red and yellow). There is probably still a preference for black and white

designs.

By 3 months:

Ocular movements are coordinated most of the time; attraction is to both black and white and colored (yellow and red) targets.

The infant is capable of glancing at smaller targets and

is interested in faces; visual attention and visual searching begins.

The infant begins to associate visual stimuli and an event

(e.g., the bottle and feeding).

By 4 months:

"Hand regard" occurs; there is marked interest in the infant's own hands.

He/she is beginning to shift gaze, and reacts (usually

smiles) to familiar faces.

He/she is able to follow a visual target past midline, and

can track horizontally, vertically, and in a circle.

By 5 monthsBy 5 months::

Eye-hand coordination (reach) is usually achieved by now.Eye-hand coordination (reach) is usually achieved by now.

The infant is The infant is able to look at an object in his/her own handsable to look at an object in his/her own hands;;

The infant is visually aware of the environmentThe infant is visually aware of the environment ("explores" ("explores" visually), and can shift gaze from near to far easily; visually), and can shift gaze from near to far easily;

By 6 months:By 6 months:

Eye movements are coordinated and smoothEye movements are coordinated and smooth; vision can be ; vision can be used efficiently at both near point and distance. used efficiently at both near point and distance.

The child The child recognizes and differentiates faces , and can reach recognizes and differentiates faces , and can reach for and grasp a visual target.for and grasp a visual target.

Hand movements are monitored visually; Hand movements are monitored visually; has visually has visually directed reach.“directed reach.“

May be May be interested in watching falling objects, and usually interested in watching falling objects, and usually fixates on where the object disappears.fixates on where the object disappears.

Between 6 and 9 months:

Acuity improves rapidly (to near normal);

"explores" visually (examines objects in hands visually, and watches what is going on around him/her).

Can transfer objects from hand to hand, and may be interested in geometric patterns.

Between 9 months and a yearBetween 9 months and a year

The child can visually spot a small (2-3mm) object The child can visually spot a small (2-3mm) object nearby; nearby;

Watches faces and Watches faces and tries to imitate expressionstries to imitate expressions;; Searches for hidden objects.Searches for hidden objects. Visually alert to new people, objects, Visually alert to new people, objects,

surroundings.surroundings. Can differentiate between known and unfamiliar Can differentiate between known and unfamiliar

people. people.

By 1 yearBy 1 year

Mild farsightednessMild farsightedness, ,

Ability to focusAbility to focus, accommodate (shift between far and , accommodate (shift between far and near vision tasks), near vision tasks),

He/She He/She can can discriminate between simple geometric discriminate between simple geometric formsforms (circle, triangle, square), scribbles with a (circle, triangle, square), scribbles with a crayon, and is visually interested in pictures.crayon, and is visually interested in pictures.

By 2 years:

• Myelinization of the optic nerve is completed.

• All optical skills are smooth and well coordinated.

• The child can imitate movements, can match

same objects by single properties (color, shape), and can point to specific pictures in a book.

By 3 yearsBy 3 years::

Retinal tissue is mature.Retinal tissue is mature. The child can complete a simple form board correctly The child can complete a simple form board correctly

(based on visual memory),(based on visual memory),

Can do simple puzzles, can drawCan do simple puzzles, can draw a crude circle, and a crude circle, and can put 1" things into holes.can put 1" things into holes.

Top 5 Milestones in Vision DevelopmentTop 5 Milestones in Vision Development

1. Focusing ability1. Focusing ability Most infants can focus accurately by two to Most infants can focus accurately by two to

three months of age. The ability to three months of age. The ability to focus focus requires special eye muscles to change requires special eye muscles to change the shape of the lens in order to form the shape of the lens in order to form clear images.clear images. Before two months of age, an Before two months of age, an infant is capable of focusing objects both infant is capable of focusing objects both near and far, but not very well. near and far, but not very well.

2. Eye Coordination and Tracking 2. Eye Coordination and Tracking A baby usually develops the ability to track and follow A baby usually develops the ability to track and follow

a slow-moving object by a slow-moving object by three months of agethree months of age. Before . Before this time, an infant will follow large, slow-moving this time, an infant will follow large, slow-moving objects with jerky motions.objects with jerky motions.

A three-month-oldA three-month-old can usually track an object quite can usually track an object quite smoothly. A baby should begin to follow moving smoothly. A baby should begin to follow moving objects with the eyes and objects with the eyes and reach for things at around four reach for things at around four months of age.months of age.

3. Depth Perception 3. Depth Perception Depth perception Depth perception is the ability to is the ability to judge judge objects that are nearer or objects that are nearer or

farther than other objects.farther than other objects. Depth perception is not present at Depth perception is not present at birth. It is not until the third to fifth month that the eyes are birth. It is not until the third to fifth month that the eyes are capable of working together to capable of working together to form a three-dimensional view form a three-dimensional view of the world.of the world.

4. Seeing color4. Seeing color An infant's color vision is not as sensitive as an adult's. It is hard An infant's color vision is not as sensitive as an adult's. It is hard

to tell if babies can distinguish colors because their eyes might to tell if babies can distinguish colors because their eyes might be be attracted by the brightness, the darkness, or the contrast attracted by the brightness, the darkness, or the contrast of an object against its surroundings, and not by the color of an object against its surroundings, and not by the color alonealone. By . By two to six weeks of agetwo to six weeks of age, however, a baby can , however, a baby can distinguish two highly contrasted colors, such as black and white.distinguish two highly contrasted colors, such as black and white.

5. Object and face recognition5. Object and face recognition An infant is born with the ability to see facial features at arm's An infant is born with the ability to see facial features at arm's

length, but is length, but is attracted instead to high-contrast borders of attracted instead to high-contrast borders of objectsobjects.. For example, a baby will gaze at the edge of a face or For example, a baby will gaze at the edge of a face or the hairline when looking at a human face. By two to three the hairline when looking at a human face. By two to three months of age, a baby will begin to notice facial features, such as months of age, a baby will begin to notice facial features, such as the nose and mouth. By three to five months, most babies can the nose and mouth. By three to five months, most babies can differentiate between mother's face and a stranger's face.differentiate between mother's face and a stranger's face.