B10 Flashcards
What kind of image does a BIO give you?
Real, inverted, and lateral reversed image formed in front of the lens
Why is BIO considered indirect?
Because the fundus is seen through a condensing lens
The image for BIO is formed close to the ____ between the lens and the observer
Principle focus of the lens
Higher power lenses offer ____FOV and can aid with examination through ___ pupils
Greater FOV and aid through small pupils
This lens is a good balance between magnification and FOV
20D lens
What 3 things does the power of the condensing lens determine?
- working distance
- magnification
- FOV
As the power of the condensing lens decreases, the FOV ___ but the working distance and magnification ____
FOV decreases, working distance and mag increases
For a 30 power lens What is the mag? What is the FOV? What is the stereo? What is the working distance from the cornea?
Mag: 2x
FOV: 60 degrees
Stereo: 1/2
Working distance: 26mm
For a 20 power lens What is the mag? What is the FOV? What is the stereo? What is the working distance from the cornea?
Mag: 3.25x
FOV: 40 degrees
Stereo: 3/4
Working distance: 47mm
For a 14/15 power lens What is the mag? What is the FOV? What is the stereo? What is the working distance from the cornea?
Mag: 4.17x
FOV: 30 degrees
Stereo: 1
Working distance: 72mm
Lens used to obtain a panoramic view when detail and stereopsis are not as important, and used with small pupil
30D lens
Which lens has the shortest working distance?
+30 lens
most widely lens used, since it provides an adequate field of view, stereopsis and magnification
20D lens
lens is most useful for detailed view of the macula or optic disc or for determining elevation of the retina in shallow retinal detachment
15D lens
What kind of lighting do you use for BIO?
Dim lighting; enough to achieve sufficient contrast
T/F: begin with the brightest light when doing BIO
False. Start lower and gradually turn it up to double check the selected area
T/F: have a sequential system for BIO
True, look in one quadrant and proceed to the next
What are the 7 advantages of BIO?
- Image is not affected by the patient’s refractive power
- Great for eyes with nystagmus
- Great for use in children
- Portable
- BIO allows for examination into the far periphery
- Large field of view
- Stereopsis
Disadvantages of BIO
-Difficult to learn
-Less magnification, therefore details of a small lesion not visualized
properly
-Impossible with very small pupils
-More uncomfortable for some patients
What are the advantages of having a systemic approach?
-Minimizing the risk of overlooking any area of the ocular fundus
-Aiding in the recall of the location of findings that are
recorded at the conclusion of the examination
The recommended approach is to complete the
examination of the ___ eye before beginning the ___eye
OD before OS
T/F: The peripheral fundus is usually examined before the posterior pole to allow the patient some time to light adapt
True
How many meridians are there when examining the fundus?
8
How do you need to stand when examining the periphery?
180 degrees away from the meridian that you wish to examine
The fundus image viewed through the condensing lens is
Inverted and reversed
Whatever appears closest to the observer in the lens is actually more ___ in the fundus
Anterior
T/F: if there is something located at the observers right within the lens it is actually located to the left on fundus
True
What are two way to indicate the location of the retinal lesion?
–Estimate the meridian in clock hours
–Estimate the distance from the posterior pole or fundus landmarks such as the equator and the ora
serrata in disc diameters
What does the color red mean for a retinal drawing of a fundus exam finding?
- Retinal arterioles
- retinal hemorrhage
- microaneurysm
- attached retina hole/break
What does the color blue mean for a retinal drawing of a fundus exam finding?
- retinal venules
- detached retina
- outline of a break
What does the color yellow mean for a retinal drawing of a fundus exam finding?
- exudate
- edema
What does the color green mean for a retinal drawing of a fundus exam finding?
- vitreous opacity
- vitreous bleed
What does the color brown mean for a retinal drawing of a fundus exam finding?
- pigmentation
- detached choroid
What does the color black mean for a retinal drawing of a fundus exam finding?
- ora serrata
- drusen
What is the disadvantage of the OCT?
Limited scanned area
What instruments can we use to look at the fundus?
- DO
- fundus bio
- BIO
- panoptic
Which ophthalmoscope gives you a direct orientation of the image?
Direct
Which ophthalmoscope give you an inverted, reversed orientation of the image?
Indirect (+20 lens)
Does the DO give you a limited or full view of the periphery
Limited
Does the indirect give you a limited or full view of periphery
Full
The depth of focus for an indirect is large or small?
Large
The depth of focus for a direct opht is small or large?
Small
What ophthalmoscope has the highest magnification?
Direct oph.
The DO give you a ___degree view
5
The BIO give you a ___degree view
45-60
What 3 conditions can you not see in the eye?
- dense cataract
- vitreous hemorrhage
- asteroid hyalosis
What does a laser do to the tissue?
It burns it
If there is dark blood and it looks like it is forward what would this be?
A pre-retinal hemorrhage
Will people with asteroid hyalosis have floaters?
Probably not
Is a asteroid hyalosis usually unilateral or bilateral?
Unilateral
Is an asteroid hyalosis a serious condition?
No
A disease where if they cant see out we cant see in
Vitreous hemorrhage
How do you treat a lattice-rt?
Laser that shit
What is the mnemonic for structures in gonio?
I- iris Cant-ciliary body See-sclera spur This- trabecular meshwork Stuff- schwalbes line
What angle is the deepest and the most pigmented when doing gonio?
Inferior angle
Why is the anatomy usually most clearly defined in the inferior angle?
Because the increasedpigmentation highlights the posterior(pigmented) TM
What angle should you always start with when going gonio?
What is the mirror view?
Inferior angle
Mirror view: 12 o’clock
When will you use the over the hill technique?
When the iris is bowed forward making the iridocorneal angle challenging
What do you want the patient to do when the persons iris is bowed?
Have the patient look into the examining mirror or tip the lens towards the angle being examined to look “over the hill” and into the angle.
T/F: if one can readily see over the hill and into the angle without indenting, the angle is not occludable
True
If you are having trouble looking at the angles what are 2 things you can do?
- look at the other eye
- do van herrick
If corneal edema precludes viewing the angle in one eye what do you do?
Look in the other eye
Are the eyes pretty symmetrical?
Why yeah
What procedure do you do for a angle closure?
Yag PI
T/F: YOU DO PERFORM A YAG PI TO PREVENT ANGLE CLOSURE IN ONE EYE – YOU DONT HAVE TO DO THE OTHER.
FALSE. Do the other eye too
How should the slit beam be when performing the Van Herrick test
Beams is made very bright and thin
The van herrick beam is offset ___ temporally to the slit lamp oculars
60 degrees
If the anterior chamber depth is as deep as the
cornea is thick then the angle is presumed to be _____
Wide open
The thickness of the cornea is compared to the ____ for van herrick
Depth of the peripheral anterior chamber
If there is only a slit of aqueous then the angle is
estimated to _____
Dangerously narrow
What is the angle grade if the chamber depth in corneal thickness is greater than or equal to the cornea?
4
What is the angle grade if the chamber depth in corneal thickness is 1/4 to 1/2 to the cornea?
3
What is the angle grade if the chamber depth in corneal thickness 1/4 the cornea?
2
What is the angle grade if the chamber depth in corneal thickness is <1/4 the cornea?
1
Describe normal vessels (4 characteristics)
- radial orientation
- thick
- non-branching
- do NOT cross the scleral spur
Describe neovascularization (3 characteristics)
- fine
- arborising (branch out like a tree)
- crosses scleral spur
Why might the angle be difficult to interpret (pigment)?
Because there is too much or too little angle pigmentation
If you have too much or too little angle pigmentation what might help with viewing and diagnosing?
Manipulations
A manipulation technique where a thin slit of light hits the irido-corneal angle at an angle of 10-15 degrees
Corneal wedge
A corneal wedge marks the ____ border of the TM
Anterior
Two light reflections when doing a corneal wedge are seen from the ____ corneal surfaces which pipe down at the sclera-corneal junction
External and internal corneal surfaces
The corneal wedge technique uses a slit lamp to create two visible lines that come together at the ___
Schwalbes line
A corneal wedge line makes it easy to identify if a patient has___
No trabecular pigmentation
The corneal wedge is useful to identify the TM in what 3 situations?
- In non-pigmented or excessively pigmented eyes it is sometimes difficult to mark where TM begins
- In young patients where the TM has not yet developed any pigmentation
- To differentiate wide-open angles and non-pigmented angle and a totally closed angle where you are looking at the internal cornea.
This technique is very useful in patients where the iris covers the TM.
Indentation gonioscopy
Name 3 situations where is easy to mistake when the iris covers the TM
- the non-pigmented TM for scleral spur
- pigmented schwalbes line for TM
- apposition of synechiae
When the iris swells during iritis and will stick to the lens or anterior chamber
Synechiae
Who will you do indentation gonio on?
On every glaucoma patient
Indentation gonio is useful when the iris surface is ____
Convex
4 reasons indentation gonioscopy is used
- differentiate appositional vs. synechial closure in pupillary block
- Measures extent of angle closure
- Identifies plateau iris configuration
- Identifies lens induced angle closure
Large or anteriorly positioned ciliary processes that push the peripheral iris forward
Plateau iris configuration
If someone has a a flat iris what test can you use?
Indentation gonio
If the scleral spur is visible this is _____
Open angle
If the scleral spur is not visible and there is synechiae what is this?
Primary angle closure (synechiae)
If the scleral spur is not visible, there isnt synechiae, and IOP is raised what is this?
Primary angle closure (apposition)
If the scleral spur is not visible, there isnt synechiae, and IOP isn’t raised what is this?
Primary angle closure suspect
Gonioscopy looks at the anterior chamber from the ____part of the iris to the ____part of the cornea using the help of the gonio lens and slit lamp
Anterior part of the iris to the posterior part of the cornea
T/F: gonio is done on all glaucoma suspects
True
How often should you do gonio on narrow angle or angle closure glaucoma patients?
Periodically
What two types of mirrors do we use when doing gonio?
3 and 4 mirror
All 4 mirrors on the lens is an angle of ___ degrees
64
Posterior curvature of all these lenses are
_____ to that of the cornea which allows the patients own tear film to form the “fluid bridge” between the lens and the surface of the cornea
Equal
Which mirror on the 3 mirror do we to see the angle mostly in gonio?
Apical mirro (D mirror)
The rectangle mirror on the gonio is called what
Peripheral mirror
The trapezoid looking mirror is called what
Equatorial mirror
Name the structures you see in gonio from posterior to anterior
Iris Ciliary body Scleral spur Trabecular meshwork Schwalbes line
Gonio is important for what kind of surgery we will be able to do someday
Peripheral iridotomy
Which mirror do you use coupling solution for
The 3 mirror
What 3 things does gonio evaluate?
- glaucoma
- iris cysts and tumors
- neovascularization of the anterior chamber
The part of the anterior chamber that you examine is ___ degrees away from the position of the mirror you use
180
When the D lens is at the 12 o clock postion what angle are you viewing?
Inferior
When the D lens is at the 3 o clock position you are examining the ___ in the OD and the ___ in the OS
OD: temporal angle
OS: nasal edge
When the D lens is at the 6o clock postion what angle are you examining?
Superior angle
When the D lens is at the 9 o clock position you are examining the ___ in the OD and the ___ in the OS
OD: nasal angle
OD: temporal angle
When removing the 3 mirror lens what do you tell the patient to do?
- to squeeze the lids firmly
What is the easiest way to avoid bubbles when you are applying the mirror lens to the cornea?
To maintain a smooth accurate motion
What is the angle of the apical (D) mirror?
59 degrees
What is the angle of the peripheral mirror?
67 degrees
What is angle of the equatorial mirror?
73 degrees
What do you see with an apical mirror?
Angle
What does the peripheral mirror look at?
Ora serrata or anterior
What does the equatorial mirror look at?
Equator
For gonio the image is ____
Inverted only
The Biomicroscopy beam is focused on the mirror that is ___to it (gonio)
Diametrically opposite
