L1,2,3 - Slit Lamp Techniques Flashcards
Diffuse illumination - Angle, Slit, Filter, Mag, Illumination
Angle - 30-45 Slit - Widest Diffuse filter Low-med (6x-16x) mag High Illumination
Diffuse illumination - Observe
Lids, lashes, conjunctiva, sclera, pattern of redness, iris, pupil, gross pathology, media opacities.
Parallelpiped - Angle, Slit, Filter, Mag, Illumination
Angle - 40-60 1-2mm slit No filter Low- med (6-16x) Mag Medium illumination
Parallelepiped - Observe
WHERE on the surface. Detect and examine corneal defect. Higher mag = corneal nerves, depth and extent of corneal scarring and foreign bodies.
Optic section - Angle, Slit, Filter, Mag, Illumination
Angle - 40-60 Minimum slit 0.1mm No filter Med - max mag (16-40x) Max illumination
Optic section - observe
How deep/ which layer. Depth of FBs or opacities.
Nerve fibres, blood vessels, infiltrates, cataracts, see wide slice of stroma.
Specular reflection - Angle, Slit, Filter, Mag, Illumination
Angle - 60 (30-30) Maximum slit 4mm No filter Low- max (10-40x) mag Med-max illumination
Specular reflection - observe
Tear film, corneal and lens surfaces, endothelium
Conical beam - Angle, Slit, Filter, Mag, Illumination
Angle - 45-60 Parrallelepiped beam, 1-2mm height No filter Start 16x mag and increase Maximum illumination
Conical beam - observe
Dark zone between cornea and anterior lens is observed to examine transparency of the anterior chamber for evidence of floating cells or flare seen in anterior uveitis
Sclerotic scatter - Angle, Slit, Filter, Mag, Illumination, decoupled / coupled
Angle 40-60 Slit parallelepiped 0.5mm No filter Maximum illumination Low-med (10-16x) mag Decoupled
Sclerotic scatter - observe
Total internal reflection of incoming light at inner corneal boundaries (halo), scars, FBs, corneal defects, corneal irregularities
Direct illumination for iris/ lens - Angle, Slit, Filter, Mag, Illumination, decoupled/ coupled
Angle - 30-50 Parrallelepiped slit at max height No filter Start with 16x mag Med-max illumination Decoupled
Direct illumination for retina - Angle, Slit, Filter, Mag, Illumination, decoupled/ coupled
Angle 0-10 Parrallelepiped slit pupil height No filter Start with 10x mag Low- med illumination Decoupled
Direct illumination- observe
Infiltrates, corneal scars, deposits, epithelial and stromal defects, keratin precipitates, other debris on corneal endothelium, water clefts, vacuoles of anterior lens, posterior sub capsular cataracts.
Indirect retro illumination- observation
Infiltrations, small scars, corneal vessels, micro cysts, vacuoles.
Van hericks - Angle, Slit, Filter, Mag, Illumination, decoupled/ coupled
Angle - 60 Minimum slit 0.1mm No filter Medium mag (10-16x) Med illumination Coupled
Van Hericks - Observation
Beam focused on the limbus, grade Anterior Chamber Angle (ACA)
Invasive tear evaluation methods
Tear Break Up Time (TBUT)
Schrimer test
Phenol-red thread test
Rose bengal staining
Heat reduction filter
Filter to remove long wavelength light, increases patient comfort and should be used when viewing the retina.
Neural density filter
Used to reduce the illumination of the beam
Red free filter
Light beam Joe takes on green appearance, used to visualise blood vessels.
Cobalt blue and wratten filter
Blue light absorbs long wavelengths.
Usually used with Sodium Fluorescein (NaFl) to detect corneal and conjunctival abnormalities, performing tonometry, assessing RGP CL fit.
Wratten 12filter
Yellow filter place in front of observation system to enhance contrast of NaFl.
Van Hericks Grades 0-4
Grade 0 - closed Grade 1 - 1<0.25 (estimated angle 10) Grade 2 - 1<0.25-0.5 (est angle 20) Grade 3 - 1<0.5-1 (est angle 20-35) Grade 4 - 1:1 (est angle 35-45)
Non invasive tear evaluation methods
Non-invasive Tear Break Up Time (TBUT)
Tear thinning time
Tear prism height
Lipid later evaluation
Normal tear prism height
0.2-1mm
Problem with using Fluorescein for Tear Break Up Time (TBUT)
NaFl destabilises the tear film
