Flashcards in Lecture 2 Deck (54)
what are 3 pupil dilation contraindications?
anterior chamber IOL, narrow angles from gonio, and plateau iris
what are the 2 diagnostic codes for a DFE?
92004 = new patient
92014 = established patient
what are 2 exceptions for when a dilated exam is part of a comprehensive exam?
patient refuses and medically contraindicated
what should you do if your patient refuses dilation at their comprehensive exam?
you still must assess the fundus - undilated 90D and/or direct scope (pt ed on importance of DFE and reschedule within 1-2 weeks)
what instruments/tools give a direct view of the retina? which give indirect?
direct = direct ophthalmoscope and goldmann 3 mirror
indirect = condensing lenses and BIO
what is the difference between a direct and indirect image?
direct = upright image (directly on observer's retina)
indirect = inverted/reversed, aerial image located between examiner's eye and condensing lens
what is the clinical standard for posterior pole examination?
using a high plus condensing lens and the slit lamp biomicroscope (dilated or un-dilated)
what are 2 reasons why fundus biomicroscopy is advantageous over direct ophthalmoscopy?
stereoscopic views and variable magnification and FOV
what is the FOV and working distance for the 90D lens?
FOV = 30-40 degrees and 7mm working distance
what is the FOV and working distance for the 78D lens?
FOV > 90D and working distance is 8mm
which lens has more magnification, 78D or 90D?
when do you use the 90D vs. the 78D?
90D = preferred lens for undilated views and periphery
78D = preferred lens for glaucoma suspects and diabetic retinopathy
what happens to the magnification as the power of the condensing lens decreases?
what happens to the FOV as the power of the condensing lens decreases?
what is the "super 90" lens?
superfield lens, diameter > 90, designed to provide same mag as 90 with > FOV and 7mm working distance
what is the "super 66"?
designed for high resolution of posterior pole, diameter > 78, mag >78D but same FOV and 11mm working distance
what is the digital high mag lens?
ideal for posterior pole = diameter and FOV similar to 78, more mag than 78 and 13mm working distance
what is the digital wide field lens?
"ultimate 90" - similar mag but larger FOV, 5-6mm working distance
what does the proper working distance of a condensing lens allow for?
the back focus of the lens to be fixed right at the pupil - permitting the examiner to move the joystick and effectively scan the full field the lens provides
what is the set-up for 90D or 78D?
medium-high illumination in click position, 10x (can move to 16x with 90D), parallelepiped beam height 5-6mm and with camera use polaroid filter and 1-3 aperture size
what are the steps to 90D/78D after the slit lamp is set up?
give patient proper target (aperture knob), center beam in red reflex of pupil (cornea in focus), hold lens at 45-60 degree angle close to eye, and pull slit lamp towards you until image is in focus
what is the order for scanning the posterior pole with 90/78D?
start with optic nerve, scan away from disc to inferior arcades, then down to superior arcades, scan nasal retina and then macula
you are examining OS superior/temporal arcades, the view is lost as you reach the outer limit of the 90D, which way should you move to keep scanning?
move lens to lens to examiner's left (direction you are scanning) - works because the views are inverted and reversed
which vessels, temporal or nasal arc around the fovea?
temporal (nasal vessels radiate straight from disc to equator)
which way should you hold your 90D lens if the patient looks up to examine superior retina?
you need to tilt the bottom of the lens closer to patient and top towards you
which way should you hold your 90D lens if the patient looks down to examine inferior retina?
tilt the bottom of the lens away from patient (towards you) and top towards the patient
which way should you hold your 90D lens if the patient looks left or right?
tilt the lens IN the direction of the patient's gaze (pt looks right = tilt lens to your right)
it is important to keep your views centered in the 90D lens - where do you have the patient look?
ask patient to look into the direction you want the image to move (ex: want ONH to move to your left, ask patient to look to their right)
what are the horizontal meridian landmarks that divide the retina into superior and inferior?
long posterior ciliary nerves at 3 and 9 o'clock
what are the vertical meridian landmarks that divide the retina into nasal and temporal?
short ciliary nerves at 10 and 2 and 4 and 6 o'clock positions
what divides the anterior and posterior retina?
the equator (vortex ampulla mark this spot)
how many vortex ampulla are there and where are they located?
at least 4-6 = located at 1,5,7,11 o'clock meridians
what is the ora serrata?
junction between retina and ciliary body (nasal appears serrated - dentate processes are more easily seen nasally)
what are the different FOV (degrees) for the mirrors on the 3-mirror?
D-shaped = 60
rectangular = 66
trapezoid = 76
what are 4 indications for the 3-mirror fundus examination?
stereoscopic exam of retina, stable view of posterior pole, magnified view of peripheral retina, and performed after BIO
what are 3 contraindications of using the 3-mirror?
severe corneal surface disease, recent eye surgery, trauma (hyphema, corneal laceration, and globe perforation)
what view does the contact hruby lens provide?
a direct upright view (larger FOV than with direct scope)
what areas of the retina are seen with the trapezoid, rectangular and d-shaped mirrors?
trapezoid = equator to PP (mid-periphery)
rectangular = equator to ora (periphery)
d-shaped = CB and pars plana
what is the set up for the 3-mirror fundus exam?
same as gonio and 78/90D - place mirror 180 from retina in question, move light into mirror and push IN with scope (not pull back)
what are the boundaries for the mid-periphery and the periphery?
mid-periphery = everything posterior of equator
periphery = between the ora and equator
what 5 things do you asses for the optic nerve?
disc size/shape, margins, contour of neuroretinal rim tissue, C/D ratio and rim tissue/NFL
what 4 things do you examine during fundus biomicroscopy?
optic nerve, vessels, posterior pole retina and macula and peripheral retina
what are you looking at when you evaluate the optic nerve head?
physiological cupping of the optic nerve (looking at the overall size of the disc to estimate the expected physiologic cup size)
how do you know if the disc size is smaller or larger than average?
use medium aperture spot on direct scope:
smaller = disc falls within spot
larger = disc falls outside spot
what is the average size of the ON?
disc diameter is about 1500 micrometers
how do you measure the ON with a slit lamp?
use narrow beam in click with 78/90D, adjust vertical height beam across the vertical optic disc inner edge and read scale
what are the conversion factors for 78 and 90D lenses?
78D = 1.2x conversion
90D = 1.33x conversion
what is the order from smallest to largest optic disc size with race?
caucasians - hispanics - asians - african americans (largest)
how does the optic disc size change for myopia and hyperopia?
greater for high myopia (>5D) and smaller for high hyperopia (>5D)
what is the cup to disc ratio?
the ratio of the physiological cup of the optic nerve to the overall diameter (divided into tenths) - estimated and recorded for horizontal and vertical ratios (record horizontal first)
what are the 5 "R" rules for optic nerve evaluation?
scleral "ring" for ON diameter, "rim" size and color, "retinal" nerve fiber layer, "region" of the peripapillary for atopy (PPA) and "retinal" and/or optic nerve hemorrhages
what is venous pulsation?
an observed pulsation of the venous arcades as they pass over the rim of the cup or at the central bifurcation
what is a scleral crescent?
"white stuff" - or direct visualization of the sclera around the ONH