UNIT THREE - Slit lamp Flashcards
FEATURES OF THE BIOMICROSCOPE:
Microscope
- binocular for depth perception
- various magnifications
- PD adjustments
FEATURES OF THE BIOMICROSCOPE:
Light source
- focusable
- adjustable width and height
- various filters (white,diffuse,ultraviolet,and red-free)
FEATURES OF THE BIOMICROSCOPE:
Other features
- joy stick for easy focusing
- height adjustment
- fixation light
- adjustable chin rest
- eye level mark
SLIT LAMP SET UP STEPS 1-8
- Set oculars on zero
- Set microscope on lowest mag
- Click light source into center position
- Wipe chin rest and headrest
- Orient patient and adjust eye level
- With the joystick, move the base of the instrument all the way to the left and all the way in (towards the patient)
- Turn in power, observe light at patients outer can thus
- Make all necessary height, width and color adjustments to the slit.
Diffuse
Light is thrown out of focus so it spreads over a large portion of the eye.
Uses of diffuse illumination
- lens position and movement
- surface wettability of the cornea or contact lens
- tear break up time
- gross corneal staining
- blink reflex
Direct
Parallelpiped and Optical Section
Light is focused into a sharp slit of 2mm or less.
Parallelpiped is what type of illumination?
Direct
What is parallelepiped?
A 1-2mm slit gives a parallelepiped section that separates the anterior and posterior cornea.
Parallelepiped is good for getting detailed look at
- corneal staining
- corneal opacities and infiltrates
- endothelial deposits
- deposits and scratches on the lens surface
Optical section is what type of illumination?
Direct
What is optical section?
A narrow slit that allows the observer to see individual layers of a transparent structure.
Optical section is used to
- determine which layer of the cornea is involved
- detect irregular topography
- view the lens/cornea relationship
Specular reflection is a variation of what illumination?
Direct
What is specular reflection?
When the lamp and microscope are at equal angles to the midline, a smooth transparent surface will reflect a mirror image of the lamp bulb.
(If not smooth, viewer sees the texture of the surface rather than the mirror image)