Slit lamp

Question 1

What are the slit lamp illumination technqiues (10)

Answer 1

Diffuse, parrallelepiped, tangential, optic section, conical beam

Indirect proximal, specular reflection, sclerotic scatter, retroillumination

Van Henrik angle

Question 2

How to carry out diffuse illumination and what part of the eye does it check

Answer 2

• wide slit with diffuser
• overall view of ocular structures and contact lens centration

Question 3

How to carry out tangential illumination and what part of the eye does it check

Answer 3

• Meidum to wide slit with low to mid magnification
• to observe surface of iris

Question 4

How to carry out parallelpiped illumination and what part of the eye does it check

Answer 4

• narrow beam (bigger than optic section) should see two lines
• Evalute depth and extent of corneal abrasions, scarring or foreign bodies (for cornea)

Question 5

How to carry out optic section illumination and what part of the eye does it check

Answer 5

• reduce width of parallelpiped to extremlyyy thin- see three lines
• estimate depth of abnormality/ determine position of cataract (more detailed view of cornea)

Question 6

How to carry out conical beam and what part of the eye does it check

Answer 6

• shorten and narrow parallelpiped to produce a circular/ sqaure spot of light with high magnification
• transparency of anterior chamber for evidence of floatnig cells and flare (for anterior chamber)

Question 7

How to check eyelids and lashes

Answer 7

• moderatly wide illumination beam

Question 8

how to examine palpebral conjunctiva

Answer 8

• use low magnification

Question 9

how to examine bulbar conjunctiva

Answer 9

• medium beam width ~ 5mm to scan

Question 10

how to examine sclera

Answer 10

• moderately wide beam with low to medium maginification w bulbar conjunctiva

Question 11

Cornea

Answer 11

• optic section, parallelpiped, specular reflection

Question 12

How to examine anterior chamber

Answer 12

• van henrick
• conical beam

Question 13

how to examine iris

Answer 13

• tangential

Question 14

How to examine crystalline lens

Answer 14

• use optic section, could reduce the verticle height
• retroillumination from the retina

Question 15

How to examine anterior vitreous

Answer 15

• narrow beam (optic section)

Question 16

How to carry out indirect proximal illumination and what part of the eye does it check

Answer 16

• narrow slit of 1 to 2mm where the beam is focused next to ocular tissue observed (optic section)
• observe structure next to the focused light beam

Question 17

How to carry out specular reflection and what part of the eye does it check

Answer 17

• seperate microscope around 60 degrees, shine at the cornea
• to check the endothelial cells (if darker than surrounding then

Question 18

How to carry out sclerotic scatter and what part of the eye does it check

Answer 18

• bright, narrow slit beam on limbus
• halo around the iris

Question 19

How to carry out retro illumination and what part of the eye does it check

Answer 19

• reflect light of a slit beam that is posterior to object
• vertical slit beam to 1 to 4mm wide (parallelpiped)
• to see sclera blood vessels

Question 20

How to carry out van henrick angle and what part of the eye does it check

Answer 20

• judge the depth of the anterior chamber near the angle
• ascertain the risk of angle closure glaucoma

Question 21

What is the grading of the van henrick angles

Answer 21

1:1 grade 4
1: 1/2 grade 3
1: 1/4 grade 2
1: <1/4 grade 1