Vitreo-Retinal Examination Flashcards
(55 cards)
We would not dilate the eye in bio under what circumstances?
Narrow angles, closed angles, need for near acuity, Iris fixed IOL
The mirrored system in BIO allows ___-axis light to ___ reflections.
Off-axis light
decrease reflections
What type of image does a BIO produce?
A real, inverted image between the lens and examiner
The prism system in the BIO decreases the examiner’s Pd to ___mm.
15 mm
The pupils of the examiner must project into the patient’s pupil to provide what?
Maximal view and stereopsis
A Method of observation in which a converging lens forms an image in the plane of the entrance pupil of the observer is called what?
Maxwellian View
Name all the components that fit into the pts pupil. What’s the exception?
Examiner’s eyes and light source
Exception = peripheral fundus views
What are the 2 stages of linear magnification?
- Patient to Aerial Image
- Aerial Image to Observer
What is the calculation for patient to aerial image linear magnification?
Mag = Deye/Dlens
ex.) 60D/20D lens = 3x mag
Aerial Image to Observer linear magnification is proportional to what?
Proportional to the distance the examiner views the image
What’s the calculation for aerial image to observer linear mag?
Mag = (Deye/Dlens)(25/d)
d= distance image is viewed (usually 40cm)
Axial Magnification is the same as depth magnification. What is the calculation for this?
Axial Mag = (linear mag)^2
use pt to aerial image linear mag
A higher powered condensing lens results in ____ axial depth?
less. (think of calculation, higher lens = less mag)
What limits the FOV of BIO?
Limited by edge of the condensing lens
In peripheral views, the pts pupil is ____. The view will be limited with vignetting.
elliptical
The higher the power of the condensing lens, the ____ the view and the ____ the mag.
The larger the view and lower the mag
How many disc diopters does a 20D lens allow in one view?
8-9
How many vortex veins do we have? In what region are they found? Where do they drain?
4 Vortex veins found in equator region
drain to ophthalmic vein
Long ciliary nerves are found where in equator?
around 3 and 9o’clock
Scleral depression is used to evaluate the peripheral lesions on profile to determine if there is a ____ or _____.
break or risk of a break..
Nasal and temporal scleral depression is harder due to____.
Lateral Canthi
What 4 things must be aligned for a sucessful scleral depression?
Eyes of examiner, lesion, light of bio, tip of depressor
When depressing, it is important to position the depressor _________the limbus
7-14mm from the limbus (mound will be under the peripheral retina)
When performing scleral depression, it is important to have a common axis of what 4 things?
Condensing lens, the depressor, pupil (pt looks away from depressor), the BI)
NOT MACULA. that means pt is looking at you
