64. Refractive Eye Problems Flashcards

1
Q
Define the following:
Ametropia
Myopia
Hyperopia
Astigmatism
Presbyopia
Amblyopia

What is the synkinetic reflex?

A

Ametropia: light doesn’t focus on retina
Myopia: light focuses in front of retina (eye too long) - NEAR SIGHTED
Hyperopia: light focuses behind retina (eye too short) - FAR SIGHTED
Astigmatism: light from different angles focuses to different distances - EGG SHAPE
Presbyopia: reduced accommodation, occurs with advancing age
Amblyopia: blurred vision due to failure of visual pathways to fully develop (before 9yrs old - no clear image to retina or eyes maligned)
Synkinetic Reflex: convergence = miosis (constriction) = accommodation

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2
Q

For Myopia, Hyperopia, and Astigmatism:

What is their axial length, corneal contour, lens contents, accommodation abilities that would explain the abnormality?

A

Myopia

  • long length
  • steep cornea
  • nuclear cataract (cloudy lens)
  • spasm of accommodation

Hyperopia

  • short length
  • flat cornea
  • aphakia (loss of natural lens)

Astigmatism

  • variable lens
  • mixed corneal contour
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3
Q

What are the ways of correcting refractive error? (Natural way and 5 tx)

A

Accommodation - natural tx for hyperopia (but synkinetic reflex causes convergens/miosis)

  1. Glasses - converging/diverging lens
  2. Contacts - correct ametropia and create new smooth corneal surface
  3. Corneal Refractive Surgery: laser/incisional/transplant - remove abnormal shape and sharpen tissue
  4. Phakic Lens implant - insert lens on top of bio lens under iris
  5. Lensectomy with IOL insertion - lens exchange - can correct near/far vision and astigmatism
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