Required Materials
- Slit lamp.
- Special tissues for over the chin support.
The Slit Lamp
This instrument [Figure 61] stands on a height-adjustable rest [1]. It consists of a support piece for the patient’s head and an optical section.
The support consists of a height-adjustable chin rest [2] and a forehead rest [3].
The slide rod [4] of the chin rest will often have a mark [5] that indicates the height at which the patient’s eyes should be for the examination.
The optical section [6] is also height-adjustable, allowing optimal positioning of the light in relation to the eye of the patient.
By using the handle [7], you can facilitate a millimetre by millimetre scan of the eye globe with the slit-shaped light beam. In the optical section, there is a light source that can be adjusted from diffuse to slit-shaped. With the diffuse light, the cornea, sclera and conjunctiva can be inspected. Various colour filters (green, blue) can be placed in front of this light source, depending on the indication for the examination.
Examine the eye by looking through two oculars [8]. These oculars can be adjusted depending on the eye distance (PD) of the examiner. If needed, the plus or minus correction of the examiner can also be adjusted.
There is also the option of looking at the patient’s eye at different magnifications [9].
Figure 61
Procedure
- Prepare the patient for the examination based on their symptoms.
- Position the patient in front of the slit lamp. The chin and forehead should slot into the rest pieces. If necessary, adjust the height of the rest to accommodate the length of the patient’s face. The corner of the eye should be at approximately the same height as the marking on the slide rod.
- Switch on the light and aim it next to the outer corner of the patient’s eye. This will avoid blinding the patient when adjusting the width and height of the light beam.
- Move the optical part so that the width of the light beam that shines on the eye is minimal.
- Use the smallest opening at the start.
- Illuminate the eye at an angle of approximately 45° and start the examination in the lateral corner of the eye. Move the narrow light beam in the medial direction across the eye globe [Figures 62, 63].
- Change to a stronger magnification when looking at certain structures or abnormalities.
- Use the blue filter when the eye has been stained with fluorescein.
- Examine the eye once more, whilst moving the light beam from the medial to the lateral side across the eye globe.
Figure 62
Figure 63