Understanding the slit lamp

Dr Carmel Crock RVEEH Melbourne, explains basics of slit lamp use

1. Eye Emergencies Dr Carmel Crock FACEM Director, Emergency Department, RVEEH 1

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3. 3 Cornea 5 layers Depth 0.5-0.8mm

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5. 5 Normal Cup/Disc ratio 0.3

6. 6 Normal retina

7. Optic disc swelling 7

8.  Malignant hypertensive retinopathy. Grosso A et al. Br J Ophthalmol 2005;89:1646-1654 ©2005 by BMJ Publishing Group Ltd.

9. Anatomy of a Slit Lamp 9

10. 10 Features Illumination system Magnification via binocular microscope

11. 11 Basic Components: illumination Bulb Filters Slit height control Slit rotator Mirror Slit width control

12. 12 Height Filters & Cobalt blue Filters 1. Unfiltered 2. Heat absorbing 3. 10% Grey 4. Red free 5. Cobalt blue 5 1 2 3 4

13. 13 Width

14. 14 Basic Components: magnification Eye pieces Magnification changer Joy stick Lock Base carriage

15. 15 Magnification Most slit lamps have: 2 objective settings (1 and 1.6) 2 eye piece options (10x and 16x) Total magnification ranges thus from 10x-25x

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17. 17 Use of the Slit Lamp Seat patient comfortably Adjust table, chair Position patient’s head

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19. 19 Focus the Microscope by Adjusting inter-puplillary distance Adjusting the eye pieces (set at 0 or dial in your refraction) Checking magnification is on 1x setting 1 2 2

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21. 21 Focus Patient’s Eye Microscope straight Light column 20-30 degrees from side Microscope moves via joystick Move laterally Move in and out Bimanual

22. 22 Adjust the Illumination Brightness: filters Width: slit vs broad beam Height: long vs pinpoint Cobalt blue

23. 23 Trouble Shooting: unable to turn it on Check all connections

24. 24 Trouble Shooting: power on - but no light Slit width closed Slit height too small Bulb burned out Bulb not positioned correctly

25. 25 Trouble Shooting: difficulty moving instrument Unlock Check patient position

26. 26 Trouble Shooting: difficulty focusing Check eye-pieces on correct setting Make sure patient’s head in correct position Adjust joy stick in and out

27. 27 Trouble Shooting: misalignment of slit and view Check magnification changer

28. 28 Anterior Segment Examination Systematic examination of the eye from front to back

29. 29 Lashes/ Lids Conjunctiva Cornea Sclera Anterior chamber -deep and quiet Iris Lens no FB no FB

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32. 32 http://eyelearn.med.utoronto.ca/default.htm

33. 33 Normal cornea

34. 34 Assessment of Depth http://eyelearn.med.utoronto.ca/default.htm

35. 35 Do not remove deep CFB Oedematous thickened cornea from deeply embedded FB

36. 36 Assessment of Depth Corneal Lesion Thin beam of light Illumination column 35-45 degrees

37. 37 Stain Cornea Use fluorescein (+/- do Seidel’s test) http://eyelearn.med.utoronto.ca/default.htm Corneal abrasions

38. Fluorescein Absorbs light in blue wavelength Emits green fluorescence 38

39. Tips - fluorescein Don’t forget to use it eg. HSV Measure size abrasion Total vs nil staining - chemical injury Fluorescein under lid – upper lid abrasion Seidel’s + or –ve -document Self sealing wounds Apply fluorescein then wait for bit to see more subtle staining 39

40. 40 Measuring Size of Lesion

41. 41 Anterior Chamber Setting up to look at anterior chamber -darkened room 1mm beam height Bright intensity illumination High magnification Is the anterior chamber deep and quiet ?

42. 42 Grading of AC Cells (counted with 1x1 mm slit) Activity Cells + 6-15 ++ 16-25 +++ 26-50 SUN 2005 Am J Opthalmol 2005: 140 : 509

43. 43 Removing a Foreign Body

44. Removal of corneal foreign body with needle and with burr

45. Step by step guide – how to use slit lamp - summary 1. clean 2. practice turn on and using 3. bring in patient - adjust chin rest, lat. canthus at line, forehead against band 4. prepare microscope - interpupillary distance, oculars set at 0, low mag 5. prepare light - low volt, 10% grey, wide beam 45

46. Step by step guide – how to use slit lamp - summary 6. Examine lids, lashes, conj, sclera, cornea, iris, lens 7. Use narrow beam to examine corneal lesion – measure depth 8. Set up to look at anterior chamber - depth, cells, flare - bright/1mm beam/high mag 9. Use fluorescein –measure size lesion 10.Turn off and clean 46