64. Refractive Eye Problems Flashcards
Define the following: Ametropia Myopia Hyperopia Astigmatism Presbyopia Amblyopia
What is the synkinetic reflex?
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
For Myopia, Hyperopia, and Astigmatism:
What is their axial length, corneal contour, lens contents, accommodation abilities that would explain the abnormality?
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
What are the ways of correcting refractive error? (Natural way and 5 tx)
Accommodation - natural tx for hyperopia (but synkinetic reflex causes convergens/miosis)
- Glasses - converging/diverging lens
- Contacts - correct ametropia and create new smooth corneal surface
- Corneal Refractive Surgery: laser/incisional/transplant - remove abnormal shape and sharpen tissue
- Phakic Lens implant - insert lens on top of bio lens under iris
- Lensectomy with IOL insertion - lens exchange - can correct near/far vision and astigmatism