Assessment And Investigative Techniques Textbook - Slit Lamp Flashcards
What is the slit width range? Why is it useful to able able to change the slit width?
1 to between 12 and 14 m, useful because it means you can measure the width of a lesion
Why is it useful to modify slit height in a slit lamp?
To measure and monitor the size of a lesion
Why is it useful to modify slit orientation
Allows the position of the axis maker to be determined via a scale on the slit lamp illumination system or in one of the eye pieces when fitting toric soft contact lenses
What’s special about decoupling on the Haag Streit type slit lamp?
It can be decoupled both horizontally and vertically useful for gonioscopy or indirect ophthalmoscopy
What are the 4 filters incorporated in the illumination system of a slit lamp?
-diffusing filter
-colbalt blue
-red free filter
-heat reducing filters
-polarising filters
-grey filter
-yellow filter
What are the uses of the colbalt blue filter?
-to view fluorescein staining on the cornea
What are the uses of the red free filter? (Actually looks Green)
to enhance red objects by making them look darker and allows blood vessels to be seen easier
What is the polarising filter used for?
Used to reduce the amount of glare useful in specular reflection
What are you checking for when you’re scanning the lid margin?
Blepharitis
What are the two types of blepharitis?
Anterior and posterior
What are the two types of anterior blepharitis?
-staphylococcal more common in females and younger patients, typically presents in patients with atopic eczema
-seborrheic
What are the complications associated with staphylococcal blepharitis?
-whitening/complete loss of lashes
-trichiasis
-scarring of the lid margin
-styes if the infection spreads
How is seborrhoeic blepharitis different to staphylococcal physically when looking at it
The scales are greasy and do not lead to bleeding when removed
Why would it be a good idea to not examine the tear film under fluorescein? What is better to examine it under?
-as it reduced the amount of ambient light so means subtle parts of the tear film get missed
-diffuse illumination and low mag means any debris in the tear film can be observed and debris can indicate blepharitis
What do you say to a patient before examining them with the slit lamp?
- Briefly explain what you’re going to do
- Obtain consent
- No technical language
- Keep explaining as the test goes on
- If you’re gonna touch the patient, tell them before hand
What are the two types of slit lamp?
Haag streit and zeiss
What is the main difference between Haag streit and zeiss?
In HS, illumination is above the microscope whereas in Z the illumination is below the microscope
What is the grey filter for?
-Decreases max brightness for photosensitive patients
What is the yellow filter for?
Good contrast enhancement when using fluroscein and the colbalt blue filter
What is the diffuser filter and what is it used for?
A flip up filter placed on the illumination source
Used for general observations of the eye and adnexa
What is the parallelpiped used for?
Assessment of the surface of the conjunctiva and the cornea
How do you take a corneal optical section?
-beam as narrow as possible
-high illumination
-mag 10-16x
-45° angle
How do you get a parallelepipid?
-3-4mm width for cornea and 2mm width for conjunctiva
-low illumination
-10-15x mag
-45° angle
How do you get an optical section of the lens?
-narrowest possible beam
-high illumination
-10-16x mag
-45°
How do you get an optical section of the anterior vitreous?
-thin beam
-high illumination
-16x mag
-decoupling so microscope is straight and illumination is at 30
