Pediatric Optometry: L2: Vision Development Flashcards
Development of Vision
- Purpose is to Build what?
- 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…
- TRANSPARENT OPTICAL SYSTEM (forming a continually focused image of the external world)
- NEURAL SYSTEM (transmit information reliably yet recalibrate constantly as a child grows)
Optical Components
- What 5 structures are important?
- Cornea
- Lens
- Aqueous
- Vitreous
- Pupil
Embryonic Period
- Time period of Gestation?
- Abnormal events result in what?
a. What 2 major events? - First evidence of Eyes seen in how many days/weeks?
- Neural Tube completed in how many days?
a. Optic Vesicle?
b. What else is formed?
- First 2 months
- Major Structural Malformations
a. Infection and Trauma - 22 days or 3 wks
- 24 days
a. Day 25
b. Optic Stalk/Nerve Formation
Fetal Period
- Time?
- Development of what?
- Disruption during this period does what?
- 9 wks to BIRTH
- Function of tissues
- Abnormalities of function
Development of the Lens
- Develops from what?
a. Fully developed on what day? - What day is the Lens Placode derived from SURFACE ECTODERM?
a. If separation fails or is incomplete, it’s called what?
- Optic Vesicle
a. Day 25 - Day 27
a. PETER’s ANOMALY
Peters Anomaly
- Lens is Adherent to what?
a. What defect occurs? - Central Corneal Opacity is what?
- Usually U/L or B/L?
- To Cornea
a. There’s a POSTERIOR CORNEAL DEFECT w/Termination of DESCEMET’s MEMBRANE where the lens is adherent to the CORNEA. - LEUKOMA (Lens stalk and “top hat” lens shape may be present)
- Typically U/L
Development of the Lens
- Formation of what?
- Hollow vesicle lined with what cells?
- What do the Posterior Cells do?
- Up to 8 Wks of Gestation, the Lens is longer in which direction?
- When the child is born, what shape is the lens?
- The Adult Lens is longer where?
- of Lens Vesicle
- Epithelial Cells
- Elongate forming Fibers
- Lens longer ANTERIOR/POSTERIOR
- Spherical at BIRTH
- Longer PARALLEL to the IRIS PLANE
Corneal Development
- Starts to develop at how many weeks?
a. How?
b. 3 Waves of Limbal Migration occur from NEURAL CREST TISSUE: What 3 things? (KNOW!) - End of 3rd Month
a. What cell layer is Adult like?
b. First evidence of what Corneal Layer? - 4th Month
a. What layer is the only layer missing?
b. When does it appear?
- 6 weeks
a. Epithelium Separates from Lens Vesicle
b. Enodthelium; Corneal Stroma; Iris Stroma
- a. Endothelium
b. of Descemet’s Membrane - a. Bowman’s Layer
b. 5th Month
Cornea
- Horizontal Diameter
a. Birth
b. 1 Year? - Vertical Diameter
a. Birth? - Surface Area
a. Birth
b. 20 Months - Keratometry
a. Birth
b. 6 Months - Thickness
a. Birth
b. 6 Months
- a. 9-10.5 mm
b. 11-12 mm - a. 10.4 mm
- a. 102 mm^2
b. 130 mm^2 - a. 51.3 D
b. 45.2 D - a. 0.96 mm
b. 0.52 mm
Development of Vitreous **If this doesn’t form properly, there can be some serious problems!
- 3 Stages
a. Primary Vitreous
b. Secondary Vitreous
c. Tertiary Vitreous - 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)
- a. 5th-6th wk
b. 6th wk to end of 3rd month
c. >12 wks - a. Hyaloid vascular system not completely regressed at birth
b. Mittendorf Dot
c. Microphthalmia; Shallow AC (Risk of Glaucoma); Lens opacities; Leukocoria or RD
Sclera
- Sclera develops from what structure?
- Migrates b/w Axons to form what?
- Scleral Fibers thicken over time: So Infant Sclera is what?
- Easily Collapsible: so what can we NOT do until a child is over 2?
- from OPTIC NERVE
- LAMINA CRIBROSA
- It’s thinner and more Elastic
- IOL Placement
Conjunctiva
- Growth of Conjunctival Fornix Mirrors Development of what?
- Sterile when?
- Bacterial Flora is adult like by when?
- Why are babies given Prophylactic Erythromycin or Silver Nitrate?
- of Palpebral Fissures
- at BIRTH!
- w/in 5 DAYS!
- Neonatal Opthalmia (N. Gonorrhoeae, and Chlamydia Trachomatis)
Iris Development
- Develops from what?
a. At what Week? - Stroma is derived from what cells?
- Dilator/Sphincter and Pigment Epithelium are derived from what?
- By Wk 12, Starting to form what?
- Outer Pigmented Layer of the Optic Cup
a. Week 8 - Neural Crest Cells
- Neuroectoderm
- the Edge of the pupil
Aniridia
- What exists, but all structures from neuroectoderm are absent?
- Associations? (3)
- Hereditary?
- Counsel on what?
- Iris Stroma Exists
- Glaucoma, Nystagmus, Low Vision
- Familial
- Sun Protection!
Iris Development
- Unknown Eye color until what age?
a. Why? - Pupillary Aperture is what at first?
- Anisocoria of up to how much is NORMAL in 9% of INFANTS?
- Pupillary response to light is present if Gestational Age is > than how many weeks?
- 1-2 years
a. Due to increased pigmentation in Iris Stroma - 1.8mm -5.4 mm initially
- up to 1 mm
- > 31 WEEKS!
Iris Development
- Iris Coloboma
a. What is it?
b. Defect in what?
- a. Incomplete closure of fetal fissure
b. Defect in INFERIOR Sector of IRIS or NOTCH in Pupillary Margin (“Keyhole Appearance”)
Globe Size at Birth
- Anterior Segment is what % of adult eye?
- Posterior Segment?
- Changes occur thru what age?
- 50% changes occur in first number of months?
- 75-80% of adult eye
- <50% of adult eye
- Age 13
- First 6 months
Axial Length
- Birth
- 0-5 years
- 6-13 years
- Adult Emmetrope
- 17 mm
- Increase by 4 mm
- Increase by 1 mm
- 22-26 mm
Orbital Development
- Orbit Volume increases thru what age?
- Orbital Margins at birth are what?
a. What do they become at Puberty? - Eyes are more What in the womb?
- thru Adulthood
- ROUND
a. OVAL - LATERAL
Orbital Development
- Anophthalmia
a. What is it?
b. Weeks after conception? - Microphthalmia
a. When does it occur?
b. What’s affected?
- a. Complete Absence of ORGAN
b. 3-6 wks after conception - a. 1st Trimester
b. Whole Organ is affected
Eyelid Development
- 3 Stages
a. Initial Development
b. Fusion
c. Reopen - Vertical Palpebral Fissure
a. Length
b. Size at Birth? - Horizontal Palpebral Fissure
a. At Birth?
b. Adult Level and at what age?
- a. Wk 6
b. Wk 11
c. Wk 28 - a. 8-8.5 mm
b. Adult like at birth - a. 18 mm at birth
b. 27-30 mm (adult levels) by age 10
Eyelid Development
- Congenital Ptosis
a. Cause?
b. Abnormal Development affects what 2 things?
c. Increased incidence w/what? - Decrease in Visual Stimulus
a. Amblyopia
b. Astigmatism
- a. Prenatal Injury (Teratogens)
b. LPS and Sup Division of CN 3
c. w/Forceps Delivery; Spontaneous cause as well. - a. Lid below MID PUPIL
b. Lids adhered tight to the GLOBE!
Lacrimal Gland Development
- Derived from what?
- Size at birth?
- from invaginations of Surface Ectoderm
2. Small at birth
Nasolacrimal System
- Open at birth?
a. Fully developed at what age? - Puncta opens at when?
- Blockage usually where?
- If underdeveloped/Blocked? (2-4% up to 20%)
- Massage how many times a day?
- % that spontaneously resolve by AGE 1?
- Fully Patent at birth
a. 3-4 yrs old - at 7 months gestation when EYELIDS OPEN!
- DISTAL PORTION where tear duct opens to nose beneath inferior turbinate (HASNERS VALVE)
- Epiphora; Recurring Infections
- 3x/day
- 80%
Crocodile Tears
- What is it?
- Reflex tearing w/Chewing
* Aberrant Facial innervation
IOP
- Birth-5 yrs: IOP will increase how much per year?
- Avg for newborn?
- 1 mmHg per year
2. 10 mmHg
Congenital Glaucoma
- Cause?
- M vs F?
- Signs?
- U/L or B/L?
- Seen at what age?
- Abnormal Development of Drainage Angle
- M»_space; F
- Megalocornea, Epiphora, Photophobia, Corneal Edema
- B/L
- 3-9 months
Juvenile-Onset Glaucoma
- What is it?
- Typically associated with what?
- Gonioscopy: Normal or Abnormal?
- Primary Open Angle
- Myopic
- Normal
Secondary Glaucoma
- Causes?
- Which of the glaucomas is MOST COMMON?
- Trauma, Uveitis, s/p Cataract Surgery
2. THIS ONE: Secondary Glaucoma
EOMs
- Recti
a. Birth: Insertion?
b. 6-9 mos?
c. 20 mos? - Obliques
a. Significant changes in Posterior segment create what?
- a. Inserted about 2 mm closer to limbus
b. ~1 mm
c. Adult Level - a. Changes in Position
Optic Nerve Hypoplasia
- What is it?
- U/L or B/L?
- Signs/Symptoms?
- Axons: Normal Amt of Decreased?
a. ONH: Normal or decreased size?
b. What does this RESULT IN?
- Congenital deficiency of RETINAL GANGLION CELLS and their AXONS
- B/L
- Asymptomatic; Decreased VA; Nystagmus; Strabismus; VF Loss
- DECREASED
a. NORMAL
b. DOUBLE RING SIGN
Neural System Development
- Coloboma
a. What is it?
b. Can affect what Retinal Structures?
- a. Defective Closure of Optic Vesicle/Fissure
b. Retina, Choroid, Optic Nerve
Retina
- Derived from what?
a. Ganglion Cells differentiate at what month?
b. Starts where? - Ora serrata starts when?
- Cell division is over before when?
- Neural Ectoderm
a. 3 Months
b. Start Centrally and Migrate Peripherally - Starts at 6 Months and Continues to Mature after birth
- When the Baby is born, but re-arrangement of cells continues after birth.
Macula
- Seen at what week?
- Ganglion cells do what?
a. What time period? - Photoreceptors migrate towards what?
a. How long?
- 11 or 12 wks
- Migrate out
a. 7 Months until 11-15 months - Toward Fovea
a. After Birth up to 5 yrs
Normal Birth Facts
- Duration?
- Gestation?
- Premature?
- APGAR Scores
a.
- 40 wks
- 38 wks
- 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
APGAR SCORE
- APGAR stands for what?
1. Appearance (Color) Pulse (HR) Grimace (Reflex Irritability) Activity (Muscle Tone) Respiration (Respiratory Effort)
Normal Birth Facts
- Avg Wgt?
- What wgt is considered low?
- Avg length?
- Visual system: Complete?
- Eye Volume does what?
- Body increases how many times?
- Visual Receptors: do they function at birth?
- 7.5 lbs
2.