L5 Refractive Errors/Pediatrics

Question 1

Describe the process to assess Visual Acuity

Numerator/Denominator?

Answer 1

Question 2

_______________: NO refractive errors

Answer 2

Emmetropia: NO refractive errors

Question 3

_______________: Shortsighted

How is this corrected?

Answer 3

Myopia: Shortsighted ( Reading is ok, Distance objects difficult)

Corrected with a CONCAVE (Divergent) Lens

Question 4

_______________: Longsighted

How is this corrected?

Answer 4

Hyperopia (Hypermetropia): Longsighted (Optical power too weak for axial length)

Corrected with a CONVEX (Convergent) Lens

Question 5

_____________: Loss of accommodative power with increasing age

How is this corrected?

Answer 5

Presbyopia: Loss of accommodative power with increasing age (Lens becomes stiffer, doesn’t move as well)

Corrected w/ BIFOCALS

Question 6

______________: decreased vision that results from abnormal visual development in infancy/childhood

Answer 6

Amblyopia: decreased vision that results from abnormal visual development in infancy/childhood

Question 7

______________: vision in one eye is worse than the vision in the other due to a difference in refractive error

Answer 7

Anisometropia: vision in one eye is worse than the vision in the other due to a difference in refractive error

• In children => interruption of visual development (Amblyopia) and Squint
• In adults => eye strain

Question 8

_______________: blurred vision due to irregular shape of the cornea => difficult to get light in focus on the retina

Answer 8

Astigmatism: blurred vision due to irregular shape of the cornea => difficult to get light in focus on the retina

Question 9

Pathology/Risks associated with Myopia?

Answer 9

Pathology:

• Tilted disk
• Atrophy of Chorioretinal Capillaries and Retinal pigment epithelium

Risks:

• Retinal Degeneration and Detachment
• Choroidal Neovascularization
• Primary Open-angle Glaucoma (POAG): bigger eye => cells are stretched out => difficult to see changes due to glaucoma

Question 10

Pathology/Risks associated with Hypermetropia (Hyperopia)?

Answer 10

If baby is very Hyperopic (> 3.50 D) – greater risk of developing Strabismus (Weakness of eye muscles)

Risk factors

• Family history
• Maternal smoking during pregnancy
• Prematurity / low birth weight
• Acute-Angle Closure Glaucoma

Question 11

If a baby is very Hyperopic (_________) – greater risk of developing ________

Answer 11

If baby very Hyperopic (> 3.50 D) – greater risk of developing Strabismus (Weakness of eye muscles)

Question 12

Cranial Nerves involved with accommodation?

Answer 12

CNII (Optic Nerve) and CNIII (Occulomotor Nerve: Innervates Ciliary Muscles)

Question 13

_________________________________: Remove corneal surface epithelium w/ a microkeratome

Answer 13

PRK (Photorefractive Keratectomy): Remove corneal surface epithelium w/ a microkeratome

• Corneal epithelium heals in days post-op

Question 14

_________________________________: Remove corneal surface epithelium w/ dilute alcohol and push back the epithelium

Answer 14

LASEK (Laser Epithelial Keratomileusis): Remove corneal surface epithelium w/ dilute alcohol and push back the epithelium

• Combines aspects of PRK + LASIK

Question 15

_______________________________: Microkeratome instrument (blade or laser) applied to corneal stroma to create a corneal flap. Flap is lifted and carefully repositioned

Answer 15

LASIK (Laser-Assisted In Situ Keratomileusis): Microkeratome instrument (blade or laser) applied to corneal stroma to create a corneal flap. Flap is lifted and carefully repositioned

Question 16

Advantages/Disadvantages of various forms of Refractive Surgery?

Answer 16

Question 17

Overall Risks of Refractive Surgery

Answer 17

Overall Risks:

• Regression, under-correction
• Risk of infection
• Dry eyes
• Flap problems
• Corneal haze, glare, trouble with driving at night (halos around lights)

Question 18

Causes/Management of Strabismus?

Answer 18

Causes:

• Refractive Error (Hyperopia, Myopia, Anismetropia (Different refractive error in each eye)
• Family history of squint (Congenital Condition)
• As an Adult: Trauma or Cranial Nerve Palsy

Management:

• Correct the cause – glasses
• Occlusion therapy to prevent amblyopia (patching of good eye => strengthens muscles of weaker)
• Surgical correction

Question 19

Types of Strabismus?

Answer 19

Question 20

Complications of Strabismus in Children and Adults?

Answer 20

Children can unconsciously suppress the image from one misaligned eye to avoid seeing double => may lead to Amblyopia and Permanent Visual Loss

Adults develop Strabismus as a result of Trauma or a Cranial Nerve Palsy
can’t suppress the image from a misaligned eye => Diplopia (Double Vision)

Question 21

Causes/Treatments of Amblyopia?

Answer 21

Causes if uncorrected (interferes w/ normal cortical visual development):

• Refractive Error (Hyperopia/Myopia)
• Anisometropia: Difference in refractive error between 2 eyes
• Strabismus (Squint)
• Congenital cataracts

Treatment (Treatable until ~ Age 8):

• Occlusion Therapy (patching of good eye => strengthens muscles of weaker)
• Atropine (relax the focusing muscles of the eye, which blurs vision in the good eye during the treatment)

Question 22

What is the Shaken Baby Syndrome Triad?

Answer 22

Brain Edema:

Intracranial Hemorrhages

Retinal Hemorraghes + Retinoschisis(Splitting in retinal layers VERY Suspicious for abuse)

Question 23

What can cause abnormalities with the Red Reflex in Infants?

Answer 23

Leukocoria (White Pupil): Diminished red reflex due to obstruction of normal retina

Causes:

• Congenital Cataracts
• Retinopathy of Prematurity (ROP)
• Retinoblastoma (Tumour at back of the Eye)