Technology in Eye Care

Question 1

2 types of tests

Answer 1

retinal imaging and visual function

Question 2

retinal imaging (technology) (3)

Answer 2

from oldest to newest:

1. ophthalmoscopy (direct, indirect)
2. fundus photography (surface of retina)
3. ocular coherence tomography (OCT) - deeper histography of retina

Question 3

direct ophthalmoscopy

Answer 3

• upright unreversed image
• 15x magnification
• natural pupil (don’t have to dilate)

disadvantages

• magnifies small area at a time
• cannot have panoramic view of eye

Question 4

indirect ophthalmoscopy

Answer 4

• inverted or reversed direct image
• 2-5x magnification
• stereoscopic inspection (both eyes)
• brighter light source
• can examine periphery better

Disadvantages

• small magnification but larger field of view (large part of retina is seen at one time)
• patient must be dilated

Question 5

optomap

Answer 5

retinal camera

200 degree view of almost entire eye

Question 6

OCT

Answer 6

slicing retina (detailed view)

• each slice/layer = A-scan
• collection of A-scans = B-scan (entire profile of eye)

(reflective index changes in layers of eye)

• advanced technology and resolution

Question 7

visual function (tests) (4)

Answer 7

Snellen Acuity - reading charts/letters

contrast sensitivity - tests lowest contrast detectable

light detection perimetry - dimmest light detectable

frequency doubling technology perimetry

Question 8

Snellen Acuity

Answer 8

1 degree = 60 s
at 20 ft, 5 mins of arc (testing distance)

nodal angle = angle where image forms

Question 9

visual field testing

Answer 9

measures ability for light detection across the visual field (behavioral perimetry)

Question 10

Electroretinogram (ERG)

Answer 10

objective assessment of visual function
- for babies, people who can’t respond

ERG electrodes, visual stimulation

Question 11

multifocal ERG

Answer 11

(objective for visual function)

• visual field mapped with miniERGs
• tests smaller regions of retina
• responses to quick flashes of light

Question 12

cataract

Answer 12

reduced contrast