Clinical: Slit Lamp 1 Flashcards
What is the formal name for a slit lamp?
Biomicroscope
What is a slit lamp?
A high powered binocular microscope with a slit shaped illumination source
What was/is the slit lamp designed to do?
View the different tissues of the eye for a general ocular health assessment
What view do we get with the slit lamp?
Binocular, stereoscopic view
Can you vary the magnification and illumination in the slit lamp?
Yes
When is a slit lamp used?
-routine ocular exam
-problem specific exams (ie something in eye)
-contact lens eval
-baseline assessment before a procedure
3 main parts/systems of the slit lamp:
-mechanical system (position control)
-illumination system (the slit lamp)
-magnification system (the biomicroscope)
What is the mechanical system used for?
-position and adjustment
-joystick for movement
-base for other parts
Parts of the mechanical system:
-motorized table
-pt positioning frame
-joystick
Biomicroscope/magnification system:
-the viewing system
-binocular for depth perception
-large working distance to allow for manipulation
How many lenses are in the optical system of the microscope?
2
What does the objective lens consist of?
2 Plano-convex lenses providing a +22D power
What does the ocular lens consist of?
+10D
Why are there prisms in the microscope system of the slit lamp?
To overcome inverted image that a compound microscope produces
What is the range of magnification on a slit lamp (typically)?
6x-40x
What areas are 6x-10x best for?
Scanning large areas
What is 16x (med mag) used for?
Evaluating details
What is high mag (>16x) used for?
Magnifying small details
What happens to field of view when magnification increase?
FOV decreases
Why is it harder to maintain clarity with increased mag?
Due to decreased depth of focus
How to focus the oculars on a slit lamp?
Turn all the way to the left (most plus) and slowly decrease the power until in focus
**do one eye at a time
The illumination system in a slit lamp provides what type of light?
Bright, evenly illuminated, finely focused, and adjustable slit of light
What does the slit shape of the light allow us to see?
Cross-sections of the ocular tissues
What do the slit controls do?
Vary height, tilt, and width of light beam
What does the reflecting mirror do?
Directs light from illumination source onto the eye
What does the illumination arm do?
Change the position of reflecting mirror to alter the angle of the slit beam
What other instruments can be used in tandem with a slit lamp?
-Goldman tonographer
-gonioscopy lens
-funduscopy lens
-cameras
-laser delivery systems
What is included in “standard set-up” of the slit lamp?
-focus the eyepieces
-adjust the PD
-bright illumination and low mag
-light source “in-click”
Where should your hands be while controlling the slit lamp?
One on the joystick and the other on the slit beam
Opaque tissues:
Eyelids, eyelashes, iris
Transparent tissues:
-tears
-conj
-cornea
-aqueous
-lens
-vitreous
Translucent tissue:
Sclera
Do you use the same technique to view all tissues?
No
Which portions appear optically empty?
-Aqueous/anterior chamber
-vitreous
Which portions of the eye can you view each layer? Why?
-cornea and lens
-do to discontinuity
What surfaces of the eye are specular reflection seen?
SMOOTH surfaces
Tear film, corneal endothelium, lens capsule
What surfaces of the eye have diffuse reflection?
Irregular surfaces of the eye
Why does light scatter?
Due to small particles suspended in a liquid or gas
What light scattering effect makes most of the ocular tissues visible?
Tyndall effect
What is the beam angle?
-The observation angle or illumination angle
-angle between the slit beam light source and the microscope line of focus
What is the beam angle range typically?
0-60 degrees
How is the beam angle changed?
By moving the light source
What is “click stop”
When the illumination arm and the microscope are in line with each other (you should feel it click into place)
What another name for the coaxial position
Parfocality
What is the coaxial position?
When the microscope and illumination are have a common center of rotation (they are aligned at the exact same spot)
