Illumination Techniques Flashcards
What is diffuse illumination good for
- Contact lens evaluations
- general overview of lids/lashes
illumination intensity is low
tall beam
mag 6-10
what is wide beam illumination good for
view of lids/lashes, conj and good “overview” of cornea
Tall beam
Medium intensity for illumination
mag at 10
What is direct illumination palalelpiped good for
examination of cornea, conj, lens and iris Tall beam 2-4 mm width angle is 20-60 medium to high illumination intensity mag is 10-16 x
direct illumination parallelpiped is used with ___ illumination, ____ reflection, and retro illumination. It is the most effective illumination at detecting tissue abnormalities. When focused sharply it provides a 3D illumination of the cornea
indirect; specular
What is optic section used for
determining the depth and location of a defect. Most commonly used for cornea or lens Narrow beam Tall beam medium to high II Mag 16 X 2D!
What are the landmarks of the optic section
- pre corneal tear film
- eptihelium
- BM
- Stroma
- DM
what is optic section useful for
- detecting changes in the cornea..thickening/thinning
- detecting the location of lenticular opacities such as cataracts
- abrasions/ulcer/foregn bodies/opactities
Normal and young crystalline lens will illuminate as a ____optic section
white; yellows with age
When determining van herick grade angle which grade are you worried about
1 and 2
Grade 1 is ____than a quarter the width of the corneal optic section. grade 4 has the width of the chamber equal to corneal optic section
less
what kind of grading would you get if you are far too centrally
angle estimation will be artificially greater
what is conical beam useful for
examining the AC conic section: 1 mm wide x 2-4 mm tall ill angle: 30-45 illuminity intensity: Max mag: 25 examiner dark adapts for 30 s
What are cells/flare indicative of
iritis/uveitis
floating cells move up near the warmer _____ and down near the cooler _____corneal surface
iris; posterior
flare =
floating protein
cells=
wbc/white dots
what is the purpose of sclerotic scatter
to look for corneal edema (loss of corneal transparency) Wide parallelpiped beam tall beam NO mag! angle: 45-60 pupil observed with naked eye!
Sclerotic scatter is the only technique that utilizes _____ of cornea
TIR
Wide beam is mostly for _____. Parallelpiped is for ____ and depth. Optic section is mostly for ____
surface; surface; depth
Angles are important in viewing the cornea and lens because it allows for viewing depth without the distraction from ____ from upper layers. Also allows for better estimation of depth and better detection/perception of _____. Angles allow for direct/indirect/retro simultaneously!
reflection; texture
what is indirect illumination good for
cornea, lens and even the retina parallelpiped beam medium intensity 10-16 mag Depends on where YOU look
What is the purpose of indirect illumination
to produce a softer illumination to give better detection and definition.
2nd most common impt technique!
Indirect is widely used for observation of cornea and corneal irregularities such as ____ _____
corneal infiltrates
Specular reflection is useful for:
looking at corneal endothelium, anterior and posterior lens capsules
Parallelpiped beam
mag 16-25
