The ocular fundus

Question 1

name the different methods of ophthalmoscopy?

Answer 1

Direct ophthalmoscope 
distant direct ophthalmoscope 
close direct ophthalmoscope 
indirect ophthalmoscope 
indirect ophthalmoscopy with convex lens 
indirect ophthalmoscopy with binocular

Question 2

describe direct ophthalmoscopy?

Answer 2

darkened room
image seen is real
high magnification (15x)
small field of vision required to assess ocular fundus -> image of eye is either equal or smaller to the eye in real time

Question 3

describe distant direct ophthalmology?

Answer 3

arms length away, the observer will look through ophthalmic lens with 0 diopter
helps differentiate between nuclear sclerosis and cataract

Question 4

describe close direct ophthalmoscope?

Answer 4

stand 3-5 cm from patient
red free filter (green light): good for viewing vasculature
Cobalt blue: used for fluorescent dye

Question 5

describe indirect ophthalmoscope?

Answer 5

induced mydriasis with tropic amide is required
good for examining all regions of the fundus while obtaining a more 3D image
Image is inverted
See larger image due to smaller field of magnification (4-5x) -> larger proportion of the fundus

Question 6

list the advantages of direct ophthalmology?

Answer 6

greater magnification
can be performed through a small pupil
ability to alter the dioptric power of the opthalamoscope

Question 7

list the advantages of indirect ophthalmoscopy?

Answer 7

larger (and often safer) working distance from the patient
larger field of view
can use with limited corneal/ lens translucency

Question 8

list the disadvantages of direct ophthalmology?

Answer 8

small field of view
difficulty in examining the peripheral fundus
greater distorsion when the cornea and lens are not transparent

Question 9

list the disadvantages of indirect ophthalmology?

Answer 9

A dilated pupil is necessary
lower magnification
more difficult to master

Question 10

describe the image seen with a fundus camera?

Answer 10

erected picture 
medium magnification (8x), and field of view

Question 11

what features are present in the dorsal half of the fundus?

Answer 11

Tapetal fundus 
Tapetum 
retina 
pigment epithelium 
- colourful 
- reflective 
choroid layer -> blood vessels

Question 12

what features are present in the ventral layer of the fundus?

Answer 12

non-tapetal fundus
coffee brown colour
retina
Pigment epithelium
- coffee brownish pigment dots in cytoplasm
- responsible for light absorption (not reflection like in tapetal layer)
choroid layer