Eye Emergencies

Dr Carmel Crock FACEM

Director, Emergency Department, RVEEH

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Cornea

• 5 layers

• Depth

0.5-0.8mm

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Normal Cup/Disc ratio 0.3

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Normal retina

Optic disc swelling

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 Malignant hypertensive retinopathy.

Grosso A et al. Br J Ophthalmol 2005;89:1646-1654

©2005 by BMJ Publishing Group Ltd.

Anatomy of a Slit Lamp

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Features

• Illumination system

• Magnification via binocular microscope

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Basic Components: illumination

• Bulb• Filters• Slit height

control• Slit rotator• Mirror• Slit width

control

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HeightFilters& Cobalt blue

Filters

1.Unfiltered

2. Heat absorbing

3. 10% Grey

4. Red free

5. Cobalt blue

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1 2 3 4

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Width

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Basic Components: magnification

• Eye pieces• Magnification changer• Joy stick• Lock• Base carriage

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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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Use of the Slit Lamp

• Seat patient comfortably

• Adjust table, chair

• Position patient’s head

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Focus the Microscope by 1. Adjusting

inter-puplillary distance

2. Adjusting the eye pieces (set at 0 or dial in your refraction)

3. Checking magnification is on 1x setting

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Focus Patient’s Eye

• Microscope straight• Light column 20-30

degrees from side• Microscope moves via

joystick• Move laterally• Move in and out• Bimanual

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Adjust the Illumination

• Brightness: filters

• Width: slit vs broad beam

• Height: long vs pinpoint

• Cobalt blue

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Trouble Shooting: unable to turn it on

• Check all connections

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Trouble Shooting: power on - but no light

• Slit width closed• Slit height too small• Bulb burned out• Bulb not positioned

correctly

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Trouble Shooting: difficulty moving instrument

• Unlock• Check patient position

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Trouble Shooting: difficulty focusing

• Check eye-pieces on correct setting

• Make sure patient’s head in correct position

• Adjust joy stick in and out

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Trouble Shooting: misalignment of slit and view

• Check magnification changer

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Anterior Segment Examination

• Systematic examination of the eye from front to back

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Lashes/ Lids

Conjunctiva

Cornea

Sclera

Anterior chamber-deep and quiet

IrisLens

no FB no FB

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

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Normal cornea

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Assessment of Depth

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

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Do not remove deep CFB

Oedematous thickened cornea from deeply embedded FB

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Assessment of Depth Corneal Lesion

• Thin beam of light

• Illumination column 35-45 degrees

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Stain Cornea

• Use fluorescein

(+/- do Seidel’s test)

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

Corneal abrasions

Fluorescein

• Absorbs light in blue wavelength• Emits green fluorescence

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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

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Measuring Size of Lesion

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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?

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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

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Removing a Foreign Body

Removal of corneal foreign body with needle and with burr

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

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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

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