65. Peds Opthalmology

Question 1

What are the key events in eye development and when do they occur?

Answer 1

W5 - lens vesicle forms
W6 - embryonic fissure closure
W7 - lens nucleus forms (neural crest cells)
Mo4 - retinal vasculature
Mo5 - eyelid separation
Mo6/7 - retinal differentiation (rods/cones)

Question 2

What is Coloboma? When does it occur?

Answer 2

Failure of embryonic fissure to close
occurs W6 (D33)
Inferonasal location in eye causes missing tissue of iris/lens/retina/optic nerve

Question 3

Retinopathy of Prematurity

• risk factors
• pathophysiology
• what is Plus Disease
• tx

Answer 3

RF: low birth weight + prematurity, prolonged O2 adminstration/blood transfusions
PP: Phase 1: extrauterine hyperoxic environment - less VEGF - vessel growth cessation - vaso-obliteration
Phase 2: ischemia - lots VEGF - abnormal neovascularization - retinal traction/detachment
Plus Disease: retinopathy requiring tx
Tx: diode laser retinal photocoagulation (sacrifice avascular retina to decrease VEGF) anti-VEGF

Question 4

Leukocoria

• what it is
• DDx and features of each

Answer 4

Asymmetric Red Reflex (usually 1 eye white)

1. Congenital Cataracts
   - cause: hereditary, toRch agent (rubella - deafness, salt/pepper fundus, congenital heart defects), metabolic disease (affects both eyes)
2. Retinoblastoma
   - can be FATAL (leukocoria is RED FLAG)
   - most common malignant intraocular tumor of childhood
   - retinal cell origin
   - signs: leukocoria, glaucoma, strabismus
   - mutation of tumor suppressor gene (RB1) and 2-hit model
   - dx: MRI (no biopsy)
   - tx: rare metastases, need enucleation (curative), systemic chemotherapy, local tx with laser
   - histo: flowery-round tumor cells

Question 5

Amblyopia

• what it is
• three key types

Answer 5

Lazy eye - abnormal development of visual system (eye + brain) = decreased vision in one eye (brain favors working one)
LEADING cause of vision loss in children
1. Strabismic Amblyopia: brain ignores misaligned eye (suppression of eye in child v. diplopia in adults)
2. Refractive Amblyopia: most common, due to myopia/hyperopia/astigmatism
3. Deprivation Amblyopia: blockage of visual input (ptosis/cataract/corneal scar) - densest/most difficult to tx

Question 6

Strabismus

• what is it
• tx

Answer 6

misaligned eyes = no stereopsis (binocular foveal 3D fixation - NOT depth perception)

tx: patching/atropine penalization of GOOD eye (improve the weaker eye), surgery to straighten eyes

Question 7

Congenital Glaucoma

• cause
• sx
• signs
• tx

Answer 7

High IOP = irreversible damage to optic nerve
Sx: blepharospasm, tearing, photophobia
Signs: large eyes, cloudy corneas, enlarged cornea diameters
Tx: IOP lowering meds, surgery