Ophthalmoscopy Flashcards
Types of ophthalmoscopy
- direct
- indirect
Direct ophthalmoscopy
- hand held instrument providing magnified monocular view inside eye
- limited FOV
Indirect ophthalmoscopy
- monocular indirect (MIO)
- binocular indirect (BIO)
Monocular indirect (MIO)
- better FOV than direct (works well with smaller pupils)
- less magnification than direct
Binocular indirect ophthalmoscopy
- allows wide field of view and stereoscopic fundus evaluation
- best used with dilated pupil
The use of lenses in conjunction with a biomicorscope (slit lamp) to view the fundus
Fundus biomicroscopy
Types of lenses used in fundus biomicroscopy
- Hruby lens
- fundus contact lenses
- non-contact condensing lenses
What is dilation
- Pharmacological enlargement of pupil via eye drops
- allows much better view into the eye
- integral part of any truly comprehensive eye care
Some patients/practices resistance to dilation
-many patients simply don’t understand the advantages
-perceived disadvantages
Blurred vision (unable to drive)
Light sensitivity (discomfort)
Long-duration
Advantages to direct ophthalmoscopy
- easier to do than BIO or fundus biomicroscopy
- provides good magnification
- ability to adjust focus (corean to retina)
Disadvantages to direct ophthalmoscopy
- limited FOV
- does not allow stereoscopic viewing (no depth perception)
- relatively dimmer image limits resolution
Clinical procedure for direct ophthalmoscopy
- pt seated just below eye level
- room dimmed
- pt looks at large distant target
- stand to side of eye to be examined
- ophthalmoscope help in same hand as eye to be examined
- using spot beam, look through scope from about 40 cm in front of patient (just temporal to their line of sight) and focus on iris
- observe retinal reflexes, looking for media opacities
- slowly move closer to pts eye while adjusting focus until fundus structures come into clear view
Direct ophthalmoscopy clinical procedure after you have discovered fundus structures
- locate ONH
- examine disc noting its appearance
- examine the area adjacent to the disc
- examine the area further out into all quadrants
- lastly, move into line of sight to examine macula
- switch sides (hands) and repeat on other eye
What to record for the ONH
- c/d ratio
- rim color
- margins
- spontaneous venous pulsation (SVP)
What to record for blood vessels
Arteriovenous (AV) ratio and any AV crossing changes
What to record for macula
- save it for last because its sensitive
- does it have homogenous color? A fovea reflex?
What is the starting point in ophthalmoscopy?
ONH
How do you record cup-to-disc (C/D) ratio:
- The ratio of optic nerve cup diameter to total optic nerve diameter
- recorded as a decimal for both horizontal and vertical dimensions, with horizontal first: H/V
Cup shape
Can be oval (different horizontal and vertical dimensions) and may be decentered
Optic nerve rim color
Normal is pinkish, well profused
Abnormal would be pallor and lack of blood flow
Optic nerve margins
Normal=distinct
Abnormal=unsure of where the edge is
Spontaneous venous pulsation
Normal but not always able to be seen
-vein going into nerve sometimes you can see it pulse with the heart rate
Blood vessel observations
AV ratio
AV crossing changes
AV ratio
Arterial/venule
Smaller lighter vessels
Arterial
Darker vessels
Veins
AV crossing changes
- arteriole usually goes overtop venules
- in atherosclerosis, arterial hardens and will press and pinch the venule down
Which vessel usually lies on top when there is AV crossing?
Arteriole
Macula observations
Record presence or absence of fovea reflex
Is direct ophthalmoscopy sufficient as a single or stand alone procedure for ocular fundus examination
No
What is direct ophthalmoscopy supplanted by?
Stereoscopic ophthalmoscopy (BIO) and biomicroscopy for comprehensive fundus eval
Why is direct ophthalmoscope important?
Its the easiest method of fundus evaluation to learn, and may be used to supplement other procedures
