Pediatric Optometry: L2: Vision Development

Question 1

Development of Vision

1. Purpose is to Build what?
2. Also needs to Build what System?
   * She will NOT ask specific Days on the Exam. Learn them regardless for Boards, but just know that if something happens in a certain time period, what abnormalities will we expect…

Answer 1

1. TRANSPARENT OPTICAL SYSTEM (forming a continually focused image of the external world)
2. NEURAL SYSTEM (transmit information reliably yet recalibrate constantly as a child grows)

Question 2

Optical Components

1. What 5 structures are important?

Answer 2

1. Cornea
2. Lens
3. Aqueous
4. Vitreous
5. Pupil

Question 3

Embryonic Period

1. Time period of Gestation?
2. Abnormal events result in what?
   a. What 2 major events?
3. First evidence of Eyes seen in how many days/weeks?
4. Neural Tube completed in how many days?
   a. Optic Vesicle?
   b. What else is formed?

Answer 3

1. First 2 months
2. Major Structural Malformations
   a. Infection and Trauma
3. 22 days or 3 wks
4. 24 days
   a. Day 25
   b. Optic Stalk/Nerve Formation

Question 4

Fetal Period

1. Time?
2. Development of what?
3. Disruption during this period does what?

Answer 4

1. 9 wks to BIRTH
2. Function of tissues
3. Abnormalities of function

Question 5

Development of the Lens

1. Develops from what?
   a. Fully developed on what day?
2. What day is the Lens Placode derived from SURFACE ECTODERM?
   a. If separation fails or is incomplete, it’s called what?

Answer 5

1. Optic Vesicle
   a. Day 25
2. Day 27
   a. PETER’s ANOMALY

Question 6

Peters Anomaly

1. Lens is Adherent to what?
   a. What defect occurs?
2. Central Corneal Opacity is what?
3. Usually U/L or B/L?

Answer 6

1. To Cornea
   a. There’s a POSTERIOR CORNEAL DEFECT w/Termination of DESCEMET’s MEMBRANE where the lens is adherent to the CORNEA.
2. LEUKOMA (Lens stalk and “top hat” lens shape may be present)
3. Typically U/L

Question 7

Development of the Lens

1. Formation of what?
2. Hollow vesicle lined with what cells?
3. What do the Posterior Cells do?
4. Up to 8 Wks of Gestation, the Lens is longer in which direction?
5. When the child is born, what shape is the lens?
6. The Adult Lens is longer where?

Answer 7

1. of Lens Vesicle
2. Epithelial Cells
3. Elongate forming Fibers
4. Lens longer ANTERIOR/POSTERIOR
5. Spherical at BIRTH
6. Longer PARALLEL to the IRIS PLANE

Question 8

Corneal Development

1. Starts to develop at how many weeks?
   a. How?
   b. 3 Waves of Limbal Migration occur from NEURAL CREST TISSUE: What 3 things? (KNOW!)
2. End of 3rd Month
   a. What cell layer is Adult like?
   b. First evidence of what Corneal Layer?
3. 4th Month
   a. What layer is the only layer missing?
   b. When does it appear?

Answer 8

1. 6 weeks
   a. Epithelium Separates from Lens Vesicle

b. Enodthelium; Corneal Stroma; Iris Stroma

2. a. Endothelium
   b. of Descemet’s Membrane
3. a. Bowman’s Layer
   b. 5th Month

Question 9

Cornea

1. Horizontal Diameter
   a. Birth
   b. 1 Year?
2. Vertical Diameter
   a. Birth?
3. Surface Area
   a. Birth
   b. 20 Months
4. Keratometry
   a. Birth
   b. 6 Months
5. Thickness
   a. Birth
   b. 6 Months

Answer 9

1. a. 9-10.5 mm
   b. 11-12 mm
2. a. 10.4 mm
3. a. 102 mm^2
   b. 130 mm^2
4. a. 51.3 D
   b. 45.2 D
5. a. 0.96 mm
   b. 0.52 mm

Question 10

Development of Vitreous **If this doesn’t form properly, there can be some serious problems!

1. 3 Stages
   a. Primary Vitreous
   b. Secondary Vitreous
   c. Tertiary Vitreous
2. PPHV (Persistent Hyperplastic Primary Vitreous)
   a. What is it?
   b. What can it result into?
   c. What can happen if the Primary VITREOUS FAILS to FORM? (4)

Answer 10

1. a. 5th-6th wk
   b. 6th wk to end of 3rd month
   c. >12 wks
2. a. Hyaloid vascular system not completely regressed at birth
   b. Mittendorf Dot
   c. Microphthalmia; Shallow AC (Risk of Glaucoma); Lens opacities; Leukocoria or RD

Question 11

Sclera

1. Sclera develops from what structure?
2. Migrates b/w Axons to form what?
3. Scleral Fibers thicken over time: So Infant Sclera is what?
4. Easily Collapsible: so what can we NOT do until a child is over 2?

Answer 11

1. from OPTIC NERVE
2. LAMINA CRIBROSA
3. It’s thinner and more Elastic
4. IOL Placement

Question 12

Conjunctiva

1. Growth of Conjunctival Fornix Mirrors Development of what?
2. Sterile when?
3. Bacterial Flora is adult like by when?
4. Why are babies given Prophylactic Erythromycin or Silver Nitrate?

Answer 12

1. of Palpebral Fissures
2. at BIRTH!
3. w/in 5 DAYS!
4. Neonatal Opthalmia (N. Gonorrhoeae, and Chlamydia Trachomatis)

Question 13

Iris Development

1. Develops from what?
   a. At what Week?
2. Stroma is derived from what cells?
3. Dilator/Sphincter and Pigment Epithelium are derived from what?
4. By Wk 12, Starting to form what?

Answer 13

1. Outer Pigmented Layer of the Optic Cup
   a. Week 8
2. Neural Crest Cells
3. Neuroectoderm
4. the Edge of the pupil

Question 14

Aniridia

1. What exists, but all structures from neuroectoderm are absent?
2. Associations? (3)
3. Hereditary?
4. Counsel on what?

Answer 14

1. Iris Stroma Exists
2. Glaucoma, Nystagmus, Low Vision
3. Familial
4. Sun Protection!

Question 15

Iris Development

1. Unknown Eye color until what age?
   a. Why?
2. Pupillary Aperture is what at first?
3. Anisocoria of up to how much is NORMAL in 9% of INFANTS?
4. Pupillary response to light is present if Gestational Age is > than how many weeks?

Answer 15

1. 1-2 years
   a. Due to increased pigmentation in Iris Stroma
2. 1.8mm -5.4 mm initially
3. up to 1 mm
4. > 31 WEEKS!

Question 16

Iris Development

1. Iris Coloboma
   a. What is it?
   b. Defect in what?

Answer 16

1. a. Incomplete closure of fetal fissure

b. Defect in INFERIOR Sector of IRIS or NOTCH in Pupillary Margin (“Keyhole Appearance”)

Question 17

Globe Size at Birth

1. Anterior Segment is what % of adult eye?
2. Posterior Segment?
3. Changes occur thru what age?
4. 50% changes occur in first number of months?

Answer 17

1. 75-80% of adult eye
2. <50% of adult eye
3. Age 13
4. First 6 months

Question 18

Axial Length

1. Birth
2. 0-5 years
3. 6-13 years
4. Adult Emmetrope

Answer 18

1. 17 mm
2. Increase by 4 mm
3. Increase by 1 mm
4. 22-26 mm

Question 19

Orbital Development

1. Orbit Volume increases thru what age?
2. Orbital Margins at birth are what?
   a. What do they become at Puberty?
3. Eyes are more What in the womb?

Answer 19

1. thru Adulthood
2. ROUND
   a. OVAL
3. LATERAL

Question 20

Orbital Development

1. Anophthalmia
   a. What is it?
   b. Weeks after conception?
2. Microphthalmia
   a. When does it occur?
   b. What’s affected?

Answer 20

1. a. Complete Absence of ORGAN
   b. 3-6 wks after conception
2. a. 1st Trimester
   b. Whole Organ is affected

Question 21

Eyelid Development

1. 3 Stages
   a. Initial Development
   b. Fusion
   c. Reopen
2. Vertical Palpebral Fissure
   a. Length
   b. Size at Birth?
3. Horizontal Palpebral Fissure
   a. At Birth?
   b. Adult Level and at what age?

Answer 21

1. a. Wk 6
   b. Wk 11
   c. Wk 28
2. a. 8-8.5 mm
   b. Adult like at birth
3. a. 18 mm at birth
   b. 27-30 mm (adult levels) by age 10

Question 22

Eyelid Development

1. Congenital Ptosis
   a. Cause?
   b. Abnormal Development affects what 2 things?
   c. Increased incidence w/what?
2. Decrease in Visual Stimulus
   a. Amblyopia
   b. Astigmatism

Answer 22

1. a. Prenatal Injury (Teratogens)
   b. LPS and Sup Division of CN 3
   c. w/Forceps Delivery; Spontaneous cause as well.
2. a. Lid below MID PUPIL
   b. Lids adhered tight to the GLOBE!

Question 23

Lacrimal Gland Development

1. Derived from what?
2. Size at birth?

Answer 23

1. from invaginations of Surface Ectoderm

2. Small at birth

Question 24

Nasolacrimal System

1. Open at birth?
   a. Fully developed at what age?
2. Puncta opens at when?
3. Blockage usually where?
4. If underdeveloped/Blocked? (2-4% up to 20%)
5. Massage how many times a day?
6. % that spontaneously resolve by AGE 1?

Answer 24

1. Fully Patent at birth
   a. 3-4 yrs old
2. at 7 months gestation when EYELIDS OPEN!
3. DISTAL PORTION where tear duct opens to nose beneath inferior turbinate (HASNERS VALVE)
4. Epiphora; Recurring Infections
5. 3x/day
6. 80%

Question 25

Crocodile Tears 1. What is it?

Answer 25

1. Reflex tearing w/Chewing | * Aberrant Facial innervation

Question 26

IOP 1. Birth-5 yrs: IOP will increase how much per year? 2. Avg for newborn?

Answer 26

1. 1 mmHg per year | 2. 10 mmHg

Question 27

Congenital Glaucoma 1. Cause? 2. M vs F? 3. Signs? 4. U/L or B/L? 5. Seen at what age?

Answer 27

1. Abnormal Development of Drainage Angle 2. M >> F 3. Megalocornea, Epiphora, Photophobia, Corneal Edema 4. B/L 5. 3-9 months

Question 28

Juvenile-Onset Glaucoma 1. What is it? 2. Typically associated with what? 3. Gonioscopy: Normal or Abnormal?

Answer 28

1. Primary Open Angle 2. Myopic 3. Normal

Question 29

Secondary Glaucoma 1. Causes? 2. Which of the glaucomas is MOST COMMON?

Answer 29

1. Trauma, Uveitis, s/p Cataract Surgery | 2. THIS ONE: Secondary Glaucoma

Question 30

EOMs 1. Recti a. Birth: Insertion? b. 6-9 mos? c. 20 mos? 2. Obliques a. Significant changes in Posterior segment create what?

Answer 30

1. a. Inserted about 2 mm closer to limbus b. ~1 mm c. Adult Level 2. a. Changes in Position

Question 31

Optic Nerve Hypoplasia 1. What is it? 2. U/L or B/L? 3. Signs/Symptoms? 4. Axons: Normal Amt of Decreased? a. ONH: Normal or decreased size? b. What does this RESULT IN?

Answer 31

1. Congenital deficiency of RETINAL GANGLION CELLS and their AXONS 2. B/L 3. Asymptomatic; Decreased VA; Nystagmus; Strabismus; VF Loss 4. DECREASED a. NORMAL b. DOUBLE RING SIGN

Question 32

Neural System Development 1. Coloboma a. What is it? b. Can affect what Retinal Structures?

Answer 32

1. a. Defective Closure of Optic Vesicle/Fissure | b. Retina, Choroid, Optic Nerve

Question 33

Retina 1. Derived from what? a. Ganglion Cells differentiate at what month? b. Starts where? 2. Ora serrata starts when? 3. Cell division is over before when?

Answer 33

1. Neural Ectoderm a. 3 Months b. Start Centrally and Migrate Peripherally 2. Starts at 6 Months and Continues to Mature after birth 3. When the Baby is born, but re-arrangement of cells continues after birth.

Question 34

Macula 1. Seen at what week? 2. Ganglion cells do what? a. What time period? 3. Photoreceptors migrate towards what? a. How long?

Answer 34

1. 11 or 12 wks 2. Migrate out a. 7 Months until 11-15 months 3. Toward Fovea a. After Birth up to 5 yrs

Question 35

Normal Birth Facts 1. Duration? 2. Gestation? 3. Premature? 4. APGAR Scores a.

Answer 35

1. 40 wks 2. 38 wks 3. 100 b. 0: Absent; 1: Weak Cry; 2: Strong Cry c. 0: Limp; 1: Flexion; 2: Active Movement d. 0: Blur or Pale; 1: Pink Body, Blue extremities; 2: Pink e. 0: None; 1: Motion; 2: Cry; Grimace and cough or sneeze

Question 36

APGAR SCORE 1. APGAR stands for what?

Answer 36

``` 1. Appearance (Color) Pulse (HR) Grimace (Reflex Irritability) Activity (Muscle Tone) Respiration (Respiratory Effort) ```

Question 37

Normal Birth Facts 1. Avg Wgt? 2. What wgt is considered low? 3. Avg length? 4. Visual system: Complete? 5. Eye Volume does what? 6. Body increases how many times? 7. Visual Receptors: do they function at birth?

Answer 37

1. 7.5 lbs 2.