L34 - visual defects 2 Flashcards
1
Q
questions to ask about visual field
A
- do things look distorted?
- is there a shadow?
- does the shadow move?
2
Q
blurred vision
A
- out of focus
- no distortion or shadows
- refractive problem
3
Q
glare
A
difficulty seeing in bright light
- corneal or lens problem
- may be due to cataracts
4
Q
distortion of vision
A
- things look wavy, jumbled up
- lines not straight
- condition affecting retina
5
Q
things look pale
A
- look dark / less colour
- optic nerve disease
- affects retina
6
Q
floater
A
- smudge
- movement
- degeneration of the vitreous (bits of it liquefy)
7
Q
where is the defect if it is homonymous
A
defect of visual pathway
8
Q
where is defect it is is heteronymous
A
retinal
optic nerve
9
Q
What are the 2 formal measurements of visual fields?
A
- Field testing by confrontation
2. Field testing by machine analyser
10
Q
field testing by confrontation
A
- doctor and patient opposite each other with opposing eyes covered
- use finger to try and compare their visual field to your visual field
11
Q
machine analyser
A
Humphrey Field Analyser
- A bowl a patient rests their chin on
- Spectacle lens to correct for their refraction
- A fixation point (dot in the middle)
- Dots of light come up at
- Patient presses button if they see light
12
Q
cataracts
A
An opacity or discoloration of the lens
*lens matures from the inside out
13
Q
blood supply to the retina
A
choroid (underneath sclera) and retinal vascular supply;y
14
Q
symptoms of cataracts
A
- gradual onset
- depend on type: blurred vision, glare, change in refraction
15
Q
where does the choroid supply
A
outer 2/3
