Direct Ophthalmoscopy Flashcards
What are the advantages and disadvantages of direct ophthalmoscopy?
Adv: upright image, easy to perform, portable, small and cheap compared to SL, 15x mag (higher than SL), can use on anterior eye, can use as volk back up.
Disadv: Small FOV, not stereoscopic, can only view central retina.
What is the mag for emmetropes, myopes and hyperopes?
Emme: 15x
Myope: >15x
Hyperope: <15x
What can help to get a good view with myopes?
Put CLs in
Wear specs?
Dilate?
Use indirect technique if poss
What can help for px’s with small pupils?
Get as close as poss
Reduce brightness and apertures
Dilate?
Remind px that they can blink
Instruct clearly on fixation
What should the largest aperture setting be used for?
Adnexa and dilated pupils
What should the medium aperture setting be used for?
Non-dilated pupils (normal examination)
What should the smallest aperture setting be used for?
Small pupils
To view macula
What should the slit aperture setting be used for?
To view contours of abnormalities in cornea, lens and retina
What should the green aperture setting be used for?
To increase contrast of blood vessels and haemorrhage
What should the blue aperture setting be used for?
To view staining when using fluorescein
What should the half aperture setting be used for?
To look around opacities
What should the graticule aperture setting be used for?
To judge size and/or distance
What should you see when checking the red reflex?
Symmetric and equal reactions
What causes a duller red reflex in one eye?
Difference in refractive error between the eyes
What causes no red reflex?
Opacity blocking red reflection of retina
