Advanced Slit Lamp Flashcards
Sometimes a _ of multiple lighting techniques will achieve the best examination. Remember to consider lighting, filters ect
combination
Diffuse illumination
When you have a second light source found on slit lamp cameras that gives overall lighting of a large general area. ( fill light)
Direct illumination
When the light is shining directly shining on area or object of interest
Indirect illumination
Is a technique that uses another structure to transfer or reflect light to highlight or focus on another structure ( which would be the area of interest)
Slit lamp illumination
Light from the slit beam that comes into sharp focus at the same distance the biomircoscope is focused on the object
Slit beam width options
8mm
Forms of direct illumination include
Optical sectioning Broad beam illumination Tangential illumination Pinpoint illumination Specular reflection
Optical sectioning
Use of narrow slit beam at 30-45 degree angels to produce a cross section of the cornea
Methods of assessing angels
- van Hedrick
- Anterior chamber depth estimate
- Penlight
- Gonioscopy
Van herick angle evaluation
Optical section
Adjust angle to 60 degrees ( oculars straight ahead)
Both temporal and nasal sides
Gonioscopy
Is a test that uses a gonio lens to view a pt angle structure/ the aqueous drainage system
Broad beam illumination
Can be used to view dystrophies or degeneration affecting large areas of cornea to examine the width and extent of corneal ulcer or defect
Tangential illumination
Shows texture and depth using varying slit beam width.
Pinpoint illumination
Reduces slit beam to a very short narrow beam of light directed at an angle across the pupil onto the iris to assess reflection in the A/C from cells and flare
Forms of indirect illumination
Proximal illumination
Sclerotic scatter
retro illumination from iris and fundus
Iris trans illumination
Proximal illumination
Uses light shone next to pathology scattering around and behind pathology increasing its contrast producing a silhouette effect
Sclerotic scatter
Used a broad slit beam that is decentered and directed at the limbus scattering light through the cornea and out the other side at limbus
Inflammatory cells in A/C from uveitis
Cells
Protein in A/C from uveitis
Flare
Specular reflection
Where the angle of the slit beam is equal to the angle of the oculars reflecting the light off smooth surface like the corneal endothelium or anterior lens capsule
Retro illumination from the fundus
Bounces light off the fundus silhouetting abnormalities in the anterior vitreous, lens, anterior chamber and cornea in silhouette form
Iris trans illumination
Detects defects in the iris pigmented epithelium by mid dilating the pupil and using retro illumination techniques with a slit beam no bigger than the pupil
Direct retro illumination from the iris
Bounces light at an angle off the iris to view corneal pathology in front of the light while in focus on the cornea
Indirect retro illumination from the iris
Bounces light at an angle off the iris to view corneal pathology not directly in front of the reflected light but off the side
Documentation
Injection: redness
Chemosis: swelling
Ecchymosis: bruising
Advanced slit lamp exam
Correctly focuses each ocular and adjust for binocular vision
Correctly positions pt
Lid/lashes broad beam illumination
Palpebral and bular conjunctiva with broad beams
Cornea with optical section illumination and broad beam
Angles with optical section illumination @60 degrees temp and nas
A/C depth with optical section illumination centrally
Anterior chamber for cells and flare with pinpoint
Iris with tangential illumination and broad beam illumination
Lens capsule with specular reflection
Lens with optical section illumination
