L1,2,3 - Slit Lamp Techniques

Question 1

Diffuse illumination - Angle, Slit, Filter, Mag, Illumination

Answer 1

Angle - 30-45
Slit - Widest 
Diffuse filter 
Low-med (6x-16x) mag
High Illumination

Question 2

Diffuse illumination - Observe

Answer 2

Lids, lashes, conjunctiva, sclera, pattern of redness, iris, pupil, gross pathology, media opacities.

Question 3

Parallelpiped - Angle, Slit, Filter, Mag, Illumination

Answer 3

Angle - 40-60
1-2mm slit 
No filter 
Low- med (6-16x) Mag
Medium illumination

Question 4

Parallelepiped - Observe

Answer 4

WHERE on the surface. Detect and examine corneal defect. Higher mag = corneal nerves, depth and extent of corneal scarring and foreign bodies.

Question 5

Optic section - Angle, Slit, Filter, Mag, Illumination

Answer 5

Angle - 40-60 
Minimum slit 0.1mm 
No filter
Med - max mag (16-40x) 
Max illumination

Question 6

Optic section - observe

Answer 6

How deep/ which layer. Depth of FBs or opacities.

Nerve fibres, blood vessels, infiltrates, cataracts, see wide slice of stroma.

Question 7

Specular reflection - Angle, Slit, Filter, Mag, Illumination

Answer 7

Angle - 60 (30-30) 
Maximum slit 4mm 
No filter 
Low- max (10-40x) mag 
Med-max illumination

Question 8

Specular reflection - observe

Answer 8

Tear film, corneal and lens surfaces, endothelium

Question 9

Conical beam - Angle, Slit, Filter, Mag, Illumination

Answer 9

Angle - 45-60
Parrallelepiped beam, 1-2mm height 
No filter 
Start 16x mag and increase 
Maximum illumination

Question 10

Conical beam - observe

Answer 10

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

Question 11

Sclerotic scatter - Angle, Slit, Filter, Mag, Illumination, decoupled / coupled

Answer 11

Angle 40-60 
Slit parallelepiped 0.5mm
No filter 
Maximum illumination 
Low-med (10-16x) mag
Decoupled

Question 12

Sclerotic scatter - observe

Answer 12

Total internal reflection of incoming light at inner corneal boundaries (halo), scars, FBs, corneal defects, corneal irregularities

Question 13

Direct illumination for iris/ lens - Angle, Slit, Filter, Mag, Illumination, decoupled/ coupled

Answer 13

Angle - 30-50
Parrallelepiped slit at max height 
No filter
Start with 16x mag 
Med-max illumination
Decoupled

Question 14

Direct illumination for retina - Angle, Slit, Filter, Mag, Illumination, decoupled/ coupled

Answer 14

Angle 0-10
Parrallelepiped slit pupil height 
No filter 
Start with 10x mag 
Low- med illumination 
Decoupled

Question 15

Direct illumination- observe

Answer 15

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.

Question 16

Indirect retro illumination- observation

Answer 16

Infiltrations, small scars, corneal vessels, micro cysts, vacuoles.

Question 17

Van hericks - Angle, Slit, Filter, Mag, Illumination, decoupled/ coupled

Answer 17

Angle - 60
Minimum slit 0.1mm
No filter 
Medium mag (10-16x)
Med illumination 
Coupled

Question 18

Van Hericks - Observation

Answer 18

Beam focused on the limbus, grade Anterior Chamber Angle (ACA)

Question 19

Invasive tear evaluation methods

Answer 19

Tear Break Up Time (TBUT)
Schrimer test
Phenol-red thread test
Rose bengal staining

Question 20

Heat reduction filter

Answer 20

Filter to remove long wavelength light, increases patient comfort and should be used when viewing the retina.

Question 21

Neural density filter

Answer 21

Used to reduce the illumination of the beam

Question 22

Red free filter

Answer 22

Light beam Joe takes on green appearance, used to visualise blood vessels.

Question 23

Cobalt blue and wratten filter

Answer 23

Blue light absorbs long wavelengths.
Usually used with Sodium Fluorescein (NaFl) to detect corneal and conjunctival abnormalities, performing tonometry, assessing RGP CL fit.

Question 24

Wratten 12filter

Answer 24

Yellow filter place in front of observation system to enhance contrast of NaFl.

Question 25

Van Hericks Grades 0-4

Answer 25

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)

Question 26

Non invasive tear evaluation methods

Answer 26

Non-invasive Tear Break Up Time (TBUT)
Tear thinning time
Tear prism height
Lipid later evaluation

Question 27

Normal tear prism height

Answer 27

0.2-1mm

Question 28

Problem with using Fluorescein for Tear Break Up Time (TBUT)

Answer 28

NaFl destabilises the tear film