Ch 1. Growth and development of the eye

Question 1

Name the normal dimensions of the newborn eye

Answer 1

Question 2

How much does the eye grow during the year of life?

Answer 2

6mm

4mm during the first 6 months and 2 additional mm during the second 2 months (fast-growth stage)

Question 3

How much does the eye grow during the second and third growth stages?

Answer 3

1 mm during each stage.

First** stage is from age **2-5 years**, **second** is form age **5-13 years.

Question 4

Approximately, how long does it take for the keratometry to reach an adult value?

Answer 4

12 months

Newborn: 52D

6 months: 46D

12 months: 42-44D

Question 5

What is the approximate power of the newborn Lens?

Answer 5

35D

_{<em>(it drops to 23D at age 2, and to 19D at age 11, where it stable) </em>}

Question 6

what is the normal refractive history of an infant?

Answer 6

Hyperopic at birth, slight hyperopic increase until age 7, and then a myopic shift until age 16, where emmetropy is usually reached.

Question 7

Which presentation age for the diagnosis of myopia, is considered to be the threshold for risk of high myopia (over 6D)?

Answer 7

Dx before 10years.

Question 8

At what age is the pupilar light reflex normally present?

Answer 8

Age 31 gestational weeks.

Question 9

Is the pediatric IOP higher or lower than in adults?

Answer 9

Lower.

An IOP higher than 21mmhg must be considered abnormal.

Question 10

How are the rectus muscle insertions different in the newborn, than those of the adult?

Answer 10

they are 2mm closer to the limbus.

_{<em>(at age 6months it is 1mm closer, and reaches adult values by the 20th month)</em>}

Question 11

At what age should vestibulo-ocular reflexes be present?

Answer 11

34 weeks’ gestational age.

Question 12

At what age should conjugate gaze be normal for horizontal and vertical gaze movements?

Answer 12

Horizontal: At birth _{<em>(intermittent strabismus can be present in up to 2/3, that resolves at age 2-3months) </em>}

Vertical: may not be fully functional until age 6 months.

Question 13

At what age should accommodation, and fusional convergence be present?

Answer 13

3 months

Question 14

What changes occure in the macula after birth?

Answer 14

• Differentiation of cone photoreceptors
• Narrowing of the rod-free zone
• An increase in foveal cone density

Question 15

What are the specific gestational ages when retinal vascularization starts and finishes?

Answer 15

Beggin at 16weeks gestaional age

Ends: 40weeks.

Question 16

At what age does normal visual acuity first reaches 20/20 in Visual Evoked Potentials?

Answer 16

6-7 months

Question 17

At what age does normal visual acuity first reach 20/20 in preferential-looking tests?

Answer 17

3-5 years

Question 18

At what age is a stereo acuity of 60 seconds of arch first achieved?

Answer 18

5-6 months