Assessment And Investigative Techniques Textbook - Slit Lamp

Question 1

What is the slit width range? Why is it useful to able able to change the slit width?

Answer 1

1 to between 12 and 14 m, useful because it means you can measure the width of a lesion

Question 2

Why is it useful to modify slit height in a slit lamp?

Answer 2

To measure and monitor the size of a lesion

Question 3

Why is it useful to modify slit orientation

Answer 3

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

Question 4

What’s special about decoupling on the Haag Streit type slit lamp?

Answer 4

It can be decoupled both horizontally and vertically useful for gonioscopy or indirect ophthalmoscopy

Question 5

What are the 4 filters incorporated in the illumination system of a slit lamp?

Answer 5

-diffusing filter
-colbalt blue
-red free filter
-heat reducing filters
-polarising filters
-grey filter
-yellow filter

Question 6

What are the uses of the colbalt blue filter?

Answer 6

-to view fluorescein staining on the cornea

Question 7

What are the uses of the red free filter? (Actually looks Green)

Answer 7

to enhance red objects by making them look darker and allows blood vessels to be seen easier

Question 8

What is the polarising filter used for?

Answer 8

Used to reduce the amount of glare useful in specular reflection

Question 9

What are you checking for when you’re scanning the lid margin?

Answer 9

Blepharitis

Question 10

What are the two types of blepharitis?

Answer 10

Anterior and posterior

Question 11

What are the two types of anterior blepharitis?

Answer 11

-staphylococcal more common in females and younger patients, typically presents in patients with atopic eczema
-seborrheic

Question 12

What are the complications associated with staphylococcal blepharitis?

Answer 12

-whitening/complete loss of lashes
-trichiasis
-scarring of the lid margin
-styes if the infection spreads

Question 13

How is seborrhoeic blepharitis different to staphylococcal physically when looking at it

Answer 13

The scales are greasy and do not lead to bleeding when removed

Question 14

Why would it be a good idea to not examine the tear film under fluorescein? What is better to examine it under?

Answer 14

-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

Question 15

What do you say to a patient before examining them with the slit lamp?

Answer 15

1. Briefly explain what you’re going to do
2. Obtain consent
3. No technical language
4. Keep explaining as the test goes on
5. If you’re gonna touch the patient, tell them before hand

Question 16

What are the two types of slit lamp?

Answer 16

Haag streit and zeiss

Question 17

What is the main difference between Haag streit and zeiss?

Answer 17

In HS, illumination is above the microscope whereas in Z the illumination is below the microscope

Question 18

What is the grey filter for?

Answer 18

-Decreases max brightness for photosensitive patients

Question 19

What is the yellow filter for?

Answer 19

Good contrast enhancement when using fluroscein and the colbalt blue filter

Question 20

What is the diffuser filter and what is it used for?

Answer 20

A flip up filter placed on the illumination source
Used for general observations of the eye and adnexa

Question 21

What is the parallelpiped used for?

Answer 21

Assessment of the surface of the conjunctiva and the cornea

Question 22

How do you take a corneal optical section?

Answer 22

-beam as narrow as possible
-high illumination
-mag 10-16x
-45° angle

Question 23

How do you get a parallelepipid?

Answer 23

-3-4mm width for cornea and 2mm width for conjunctiva
-low illumination
-10-15x mag
-45° angle

Question 24

How do you get an optical section of the lens?

Answer 24

-narrowest possible beam
-high illumination
-10-16x mag
-45°

Question 25

How do you get an optical section of the anterior vitreous?

Answer 25

-thin beam
-high illumination
-16x mag
-decoupling so microscope is straight and illumination is at 30