Ординатура / Офтальмология / Английские материалы / The Slit Lamp Primer_Ledford, Sanders_2006
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18 Chapter 2
Figure 2-7. Set the transformer to the lowest or mid voltage setting. (Photo by Mark Arrigoni.)
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Turn the transformer on at the lowest or mid voltage setting (Figure 2-7). Using the lower settings extends the bulb’s life. A sudden surge of higher-voltage power through a bulb can cause the bulb to blow. The lower setting is adequate for most examination purposes, anyway.
If nothing happens when you turn on the instrument you will need to play detective and figure out what is going on. Start with the most simple things and go from there:
•Is the slit beam misdirected (via scanning control ring or slit centering knob)?
•Is the slit beam closed?
•Is something obstructing the optical head?
•Is a filter halfway engaged?
•Is the main switch on? How about any secondary power switches?
•Is there a good connection between the transformer and lamp?
•Is there a good connection between the transformer and the power source?
•Is the instrument plugged in?
•Has the bulb blown?
•Has the fuse blown?
•Have you blown a circuit breaker?
If all of these items check out, refer to your instruction manual and call the manufacturer, if necessary.
Fixation
Giving the patient something to look at while you examine him or her helps hold the eye steady. If your slit lamp has a fixation light, have the patient look at that (Figure 2-8). If you do not have a fixation device, you can ask the patient to look straight ahead at your ear or over your shoulder at a large letter or other target at the end of the room. (Remember that the target may be obscured at times as you swing the light source back and forth.) Encourage the patient to keep both eyes open and to blink now and then.
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Magnification |
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It is a good idea to begin the examination at 6X or 10X magnification. You can move to 16X |
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or more when you examine the cornea and internal structures and when you see some abnormal- |
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ity that warrants closer inspection. Remember that the higher the magnification setting, the more |
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magnified the patient’s movements become. A tiny flutter may be barely noticeable at 6X but take |
The Basic Slit Lamp Exam 19
Figure 2-8. Using a fixation light can help reduce eye movement during the exam. (Photo by Mark Arrigoni.)
Figure 2-9. One hand manipulates the joystick, and the other hand operates the light source. (Photo by Val Sanders.)
your object of interest totally out of the field at 40X. Table 2-1 lists suggested magnifications for various parts of the slit lamp exam.
Manipulating the Light Source
The ideal examiner position is to have one hand on the light source and the other hand on the joystick (Figure 2-9). The hand on the light source can manipulate beam width, angle, and height usually at the same time.
Focusing
In a previous section, we instructed you to move the stage over to the forward left corner once the patient is positioned. If the beam is not narrow when the light is turned on, narrow it now. Angle the light at about 45 degrees. Move the stage to the right (keeping forward as much as possible without physically contacting the patient), allowing the beam to fall on the patient’s face. If the beam is lower or higher than the eye, rotate the joystick (or the joystick ring) to make the beam level with the eye. Now, slide the stage right until the beam falls on the patient’s temporal canthus of the right eye.
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Continued on page 28
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Chapter 2 |
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TABLE 2-1 |
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SLIT LAMP EXAMINATION |
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Suggested Power |
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6X or 10X |
external (lids, conjunctiva), contact lenses |
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16X |
angles, cornea, lens, foreign bodies, corneal abrasions |
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40X |
corneal endothelium (described in text) |
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Beam Width |
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narrowest (Figure 2-10) |
angles, cornea, anterior chamber |
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2 |
a bit wider (Figure 2-11) |
cornea, lens, etc |
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3 |
a bit wider yet (Figure 2-12) |
external, contact lenses |
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4 |
full width (Figure 2-13) |
external, applanation tension (with blue filter) |
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Beam Height |
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full |
most areas and structures |
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short (Figure 2-14) |
checking anterior chamber for cells & flare |
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Color/Filter |
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white |
most areas and structures |
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blue |
(use fluorescein dye) applanation tensions, corneal staining, |
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tear film, staining patterns of rigid contact lenses |
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green (red-free) |
evaluating blood vessels, iron lines |
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Position (of light source) |
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R= right L= left C= center
degrees (given; indicated at base of illumination arm)
Stage (position)
R= right
L= left
Abbreviations
OD |
right eye |
OS |
left eye |
SCH |
subconjunctival hemorrhage |
AC |
anterior chamber |
SPK |
superficial punctate keratopathy |
PEE |
punctate epithelial erosions |
PSC |
posterior subcapsular cataract |
AT |
applanation tension |
Note: Unless contraindicated, fluorescein is instilled before slit lamp exam begins. Abnormalities are explained in Chapter 5.
The Basic Slit Lamp Exam 21
Table 2-1 (continued)
SLIT LAMP EXAMINATION
Suggested Slit Lamp Exam Protocol
Settings |
Area/Structure |
Observe for |
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OD Lids (Figure 2-15) |
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Power: 10X |
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blepharospasm |
Width: 2 to 4 |
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collarettes |
Height: full |
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coloboma |
Color: white |
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crusting/matting |
Position: R, sweep to L |
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discharge |
Stage: L |
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edema (swelling) |
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erythema |
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growths |
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lash loss |
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lid closure |
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lid lag |
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lid position |
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notching |
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reflux |
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trauma |
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OS Lids |
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Position: R, sweep to L |
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Stage: R |
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OD Conjunctiva, Episclera, Sclera (Figure 2-16) |
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Power: 10X to 16X |
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ciliary flush |
Width: 2 |
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color |
Position: L, sweep to R |
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dryness |
Stage: L |
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edema (chemosis) |
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follicles |
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foreign body |
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growths |
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injection |
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leash vessels |
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papillae |
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pinguecula |
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scleral show |
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scleral thinning |
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SCH |
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trauma |
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OD Tear Film |
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Power: 10X to 16X |
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break up time |
Width: 2 |
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debris |
Position: L, sweep to R |
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discharge |
Stage: L |
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epiphora |
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OD Cornea (Figure 2-17) |
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Width: 2 |
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abrasion |
Position: L, sweep to R |
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arcus senilis |
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dellen |
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dystrophy |
22 Chapter 2
Table 2-1 (continued)
SLIT LAMP EXAMINATION
Suggested Slit Lamp Exam Protocol
Settings |
Area/Structure |
Observe for |
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OD Cornea (Figure 2-17) (continued) |
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edema filaments foreign body ghost vessels guttata infiltrates iron lines
keratitic precipitates keratitis keratopathy Krukenberg spindles opacities
pannus phlyctenule pterygium rust ring scar stria/folds ulcer vascularization
OD Corneal Staining |
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Color: blue |
abrasion |
Position: L, sweep to R |
bullae |
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dendrites |
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dry spots |
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PEE/SPK |
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stained areas |
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tear film |
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ulcer |
OD Temporal Angle (Figure 2-18) |
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Power: 16X |
AC depth |
Width: 1 |
angle grade |
Color: white |
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Position: L, ~45° |
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OD Nasal Angle |
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Position: R, ~45° |
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OD AC (Figure 2-19) |
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Width: 1 to 2 |
hyphema |
Position: L, sweep to R |
hypopyon |
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vitreous |
Width: 1 |
cells |
Height: small |
flare |
Position: L, sweep to R with |
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vertical searching motions |
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The Basic Slit Lamp Exam 23
Table 2-1 (continued)
SLIT LAMP EXAMINATION
Suggested Slit Lamp Exam Protocol
Settings |
Area/Structure |
Observe for |
OD Iris/Pupil (Figure 2-20) |
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Width: 2 |
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atrophy |
Height: full |
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coloboma |
Position: L, sweep to R |
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iris detachment |
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iris movement |
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iris nevus |
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iris strands |
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laser iridotomy |
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normal iris vessels |
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peripheral iridectomy |
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pigment dispersion |
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pupil reaction |
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pupil shape |
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rubeosis |
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sector iridectomy |
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synechiae |
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OD Lens (Figure 2-21) |
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cortical spoking |
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nuclear sclerosis |
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opacities |
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PSC |
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pseudoexfoliation |
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subluxation |
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vacuoles |
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OD Intraocular Lens |
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capsule opacity |
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capsulotomy |
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location |
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position |
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precipitates |
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OD Anterior Vitreous |
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Position: L, sweep to R |
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clarity |
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opacities |
OS Conjunctiva and Globe
(repeat process using opposite directions)
AT, OD
Power: 6 or 10X
Height: full
Width: full
Color: blue
Position: L, ~60°
Stage: L
AT, OS
Position: R
Stage: R
24 Chapter 2
Figure 2-10. Thin vertical slit beam. (Reprinted with permission from Ophthalmic Photography, SLACK Incorporated. Photo by Steve Carlton.)
Figure 2-11. Slightly wider beam. (Photo by Val Sanders.)
Figure 2-12. The beam is wider yet. (Photo by Val Sanders.)
The Basic Slit Lamp Exam 25
Figure 2-13. Wide open slit beam. (Reprinted with permission from Ophthalmic Photography, SLACK Incorporated. Photo by Steve Carlton.)
Figure 2-14. Pinpoint beam. (Photo by Val Sanders.)
Figure 2-15. Lids, right eye. Moderately wide beam. (Photo by Val Sanders.)
26 Chapter 2
Figure 2-16. Examining the temporal conjunctiva, episclera, and sclera. (Photo by Val Sanders.)
Figure 2-17. Cornea, right eye. (Photo by Val Sanders.)
Figure 2-18. Evaluating the temporal angle, right eye. Notice the dark interval between the corneal section and the light reflection on the iris. Narrowest beam at full height. (Photo by Val Sanders.)
The Basic Slit Lamp Exam 27
Figure 2-19. Examining the anterior chamber, right eye. Note that the beam is not sharply focused on either the cornea or the iris, indicating that it is focused on the anterior chamber. (Photo by Val Sanders.)
Figure 2-20. Iris and pupil, right eye. (Photo by Val Sanders.)
Figure 2-21. Right lens. (Photo by Val Sanders.)