paeds ophthal

Question 1

snellen acuity at birth

Answer 1

6/300

Question 2

snellen acuity at 12 months

Answer 2

6/24

Question 3

snellen acuity at 36 months

Answer 3

6/9-6/6

Question 4

what age can start using snellen chart (6m) to test VA

Answer 4

4 yo and above

Question 5

visual assessment in preverbal children

Answer 5

1. fixation preference
2. forced preferential looking (teller cards)

Question 6

visual assessment in older children

Answer 6

1. allen pictures
2. kay pictures
3. sheridan gardner matching test
4. snellen

Question 7

amblyopia (lazy eye) definition

Answer 7

Unilateral (or rarely bilateral) BOV due to disruption in normal visual development, caused by abnormal visual stimulation during sensitive period of visual development

Question 8

VA criteria for amblyopia

Answer 8

• Unilateral amblyopia: difference in BCVA is 2 or more Snellen lines between 2 eyes
• Bilateral amblyopia: BCVA of 6/12 or less

Question 9

pathophysiology of amblyopia

Answer 9

*Development of lateral geniculate nucleus and primary visual cortex is incomplete at birth and persists into postnatal period
*During critical period when there’s plasticity within visual system esp visual cortex, external factors can modify its development

Question 10

causes of amblyopia

Answer 10

1. strabismus (commonest)
2. stimulus deprivation
3. refractive error (anisometropia (2 eyes diff RE), ammetropia (both eyes deg high), astigmatism)

Question 11

criteria for anisometropia

Answer 11

any of:
hyperopia > 1.5D
myopia > -3-4D
astigmatism > 1.5D

Question 12

criteria for ammetropia

Answer 12

hyperopia >5D
myopia <-8D

Question 13

criteria for astigmatism

Answer 13

> 2.5D

Question 14

screening for amblyopia

Answer 14

1. measure VA
2. Holler test - child upset when good eye covered

Question 15

principles of management for amblyopia

Answer 15

1. provide clear retinal image
2. correct ocular dominance
3. parental counselling

Question 16

how to provide clear retinal image

Answer 16

*identify and correct RE
*fulltime spectacle wear for refractive amblyopia

Question 17

how to correct ocular dominance

Answer 17

*occlusion therapy (gold std): patch good eye to force fixation by amblyopic eye
*topical atropine cycloplegic eyedrops in good eye (paralyses accommodation causing blurring in good eye): use amblyopic eye, not useful in dense amblyopia or myopes (near vision preserved even on eyedrops)

Question 18

when is tx possible for amblyopia

Answer 18

critical period <7-8yo, best time to correct during infancy or early childhood (<4-5 yo)

Question 19

what is strabismus

Answer 19

ocular misalignment

Question 20

heterophoria vs heterotropia

Answer 20

heterophoria: latent strabismus, deviation not seen when pt focusing with both eyes
heterotropia: strabismus, deviation seen even when pt using both eyes

Question 21

assessment for strabismus

Answer 21

1. visual acuity
2. Hirschberg corneal light reflex
3. cover test
4. simultaneous red reflex (check ocular alignment)
5. extraocular eye movements in all 9 positions of gaze
6. stereoacuity (3D vision)
7. full eye and neurological examination

Question 22

complications of strabismus

Answer 22

1. amblyopia: squint eye becomes amblyopic (if child develops fixation preference)
2. poor binocular vision
3. abnormal head posture

Question 23

comitant vs incomitant strabismus

Answer 23

comitant: non paralytic
incomitant: paralytic (eye movement limited due to EOM paralysis)

Question 24

management of strabismus

Answer 24

1. botulinum toxin injection
2. corrective/prism glasses
3. strabismus surgery

Question 25

leukocoria

Answer 25

white pupil or white reflex urgent referral

Question 26

abnormal red reflexes

Answer 26

*Absent red reflex/ asymmetry (1 eye no red reflex, other eye RR present) *White reflex (1 eye white, other eye RR present) normal RR: both eyes RR present

Question 27

5 causes of leukocoria

Answer 27

1. retinablastoma (most impt TRO) 2. congenital cataract 3. persistent fetal vasculature / persistent hyperplastic primary vitreous (PHPV) - small eye 4. advanced retinopathy of prematurity (with tractional retinal detachment stage IV/V) 5. coat's disease/exudative retinal telangiectasis

Question 28

retinoblastoma age

Answer 28

before 3yo

Question 29

inx for retinoblastoma

Answer 29

CT and MRI (CT if only for dx)

Question 30

mx of retinoblastoma

Answer 30

*Local Tx (e.g. cryotherapy/laser) for small tumours * Radiotherapy * Chemotherapy * Enucleation (eye removed) for very large tumours in eyes of no visual potential *Intra-arterial chemotherapy * Screen siblings, genetic counselling

Question 31

ophthalmia neonatorum time period

Answer 31

first 28 days of life

Question 32

organisms involved in ON

Answer 32

Neisseria gonorrhea chlamydia trachomatis serovars D-K *do conjunctival swab

Question 33

presentation on ON

Answer 33

1. Purulent conjunctivitis 2. profuse exudate/discharge 3. eyelid swelling

Question 34

cx of ON

Answer 34

Infection can extend from superficial epithelial layers into subconjunctival connective tissue and cornea --> corneal ulceration, corneal scarring, blindness

Question 35

mx for ON

Answer 35

1. Admit child for observation 2. IM ceftriaxone + PO azithromycin for Neisseria, PO erythromycin for Chlamydia 3. Treat mother, screen her sexual partners for sexually transmitted diseases and treat

Question 36

Disseminated disease by organisms causing ON

Answer 36

sepsis, septic arthritis, meningitis