week 4 co2

How can you improve your slit-lamp technique?

• optimise lighting/mag

What are common errors with slit lamp?

• patient not set up correctly

• Eyepieces not focussed correctly

• When beam is narrower, brightness should be increased

• Angle of illumination arm should be varied, greater when looking at cornea than lens and lined up for fundus

• Magnification should be varied throughout

What is the process of setting up the slit lamp?

What is the suggested routine of what structures you should look for?

What are the key aspects of diffuse illumination?

• low illumination

• Low magnification

What do you use diffuse illumination for?

Lids, lashes, eyelid disease, conjunctiva, corneal abnormalities

• make sure to look under lids

• Ask px to look in all directions

What do you use eyelid eversion for?

• look under the upper lid to examine palprebral conjunctiva

• Looking for excessive redness and roughness

What do you use parallelepiped and optic section for?

Detailed examination of the cornea

What are the key features of parallel piped?

• width of beam, similar to depth of cornea

• Use this illumination to scan across cornea - upper, middle and lower

What are the key features of optic section?

• ensure slit is as thin as it can be

• Illumination at max

What can you see with optic section?

What method is used for this?

Optic section

What do you use van herick’s for?

• The anterior chamber

• Compare AC depth to the cornea

What are key aspects of van herick’s?

• angle 60 degrees

• beam just inside limbus

• Ensure high brightness

Describe this method and what structures can be seen

• van herick’s

• Cornea, anterior chamber and iris

• Looking for 1:1 ratio (100%)

What grading scale do you use for van herick’s?

• 0-4 grading scale or percentage

• Eg: 1:1 = 100%

• 1:0.25 = 25%

What angle percentage do you consider a referral?

Less than 15%

Memorise

What % is this?

1:1 = 100%

What % is this?

1:0.25 = 25%

What % is this?

5%

Describe direct, indirect and retro illumination

What do you use specular reflection to observe?

Corneal endothelium, espc prior to cataract surgery and tear film

What are the key aspects of specular reflection?

• medium illumination

• Highest mag

What method is being observed and what structures are being viewed?

Specular reflection

Whst method and what structures is being observed?

Specular reflection and endothelium

What is the purpose of decoupling the slit lamp?

• places light at a different place than the eyepieces are viewing

What method uses decoupling a slit lamp?

Sclerotic scatter

Which structure is being illuminated in sclerotic scatter?

The limbus

What do you use fluroscein for?

Corneal staining caused by dryness or abrasion

How do use corneal staining?

• instil fluroscein

• Use cobalt blue and written filter

• Look with wide beam and low mag

• Then scan using a parallel piped and x16 mag

• Check whole cornea

• Record by drawing

What’s going on here?

Corneal staining

Tear break-up

What’s going on here?

Dryness

What’s going on here?

Punctate staining

What are grade findings?

• compare your findings to photograph

• Use 0.5 steps

• Same scale each visit

• Support finding with drawing where appropriate

What are the advantages of grading scales?

• improves record keeping

• Allows change monitoring

• Improves decision making

• Improves reliability

• Reduces intra and inter practioner variability