Ординатура / Офтальмология / Английские материалы / Practical Ophthalmology A Manual for the Beginning Ophthalmology Residents 4th edition_Wilson_1996
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Patient looking down
Patient looking straight ahead
Patient looking up
Figure 1
206
Clinical Protocol 9.9
Palpating the Orbit
Orbital Rim
1.Palpate the anterior portion of the orbit by placing a finger between the orbital margin and the globe. Standing behind tlie patient may make it easier to roll the small finger around the orbital rim.
2.Begin laterally. The lateral orbital margin is generally about 5 mm from the lateral canthus.
3.Slowly move upward (clockwise on the patient's right orbit and counterclockwise on the left orbit). Locate the supraorbital notch or foramen by
gently moving your fingertips along the orbital rim, at the junction of the medial one third and lateral two thirds of the superior orbital margin.
4.Move your fingertips medial to the supraorbital notch. Feel for the trochlea, normally palpable 4 mm posterior to the orbital margin. The upper border of the medial canthal ligament can be felt just below this point.
5.Move your fingertips along the inferior orbital margin, which should form a smooth, continuous contour. A vertical line extending from the supraorbital notch intersects the palpable infraorbital foramen, 4 mm below the inferior orbital margin.
6.Move your finger along the outer orbital rim and feel the marginal tubercle of the zygomatic bone. Approximately 6 mm above this point is the junction of the frontal and zygomatic bones, which is palpable at the supraorbital margin. The frontozygomatic suture is about 10 mm from the lateral canthus.
Orbital Contents
1. After completing the circumference of the orbital rim, gently touch the patient's closed eyelids.
a.Any thrill or pulsation movement should be noted.
b.If a sinus fracture is suspected, move the fingers around the globe to
detect any crepitus within the confines of the orbital margin.
c.Press gently into the periocular tissues to feel for the anterior extension of a retrobulbar or anterior orbital mass.
continued
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2.Judge the resiliency of the retrobulbar tissues by cautiously pushing the globe posteriorly through the patient's closed evelids. Normally the eye can be displaced into the orbital fat about 5 mm. By comparing the two orbits, the degree and ease of globe retropulsion are assessed.
3. Ask the patient to perform a Valsalva maneuver. Judge whether any pressure is transmitted to the orbits by keeping your fingertips pressed onto
both globes through the patient's closed eyelids during the maneuver.
'+
Clinical Protocol 9.10
Measuring Lacrimal Outflow in the
Tearing Patient
i
Lacrimal Sac Compression
1. Apply pressure by gently pushing your index finger or a cotton-tipped applicator stick over the lacrimal fossa inside the inferomedial orbital rim (not on the side of the nasal bone).
Figure 1 |
;f Fi incis C.Sutula, MD. Reprinted by : |
Iprbit, Eyelids, or, |
• Clinical Science Course, |
Francisco: Amer |
...„;;ology;1996.) |
Jf08
2. Note any mucus or mucopurulent material that can be expressed back through the canaliculi and puncta. Reflux confirms a completely obstructed nasolacrimal duct (Figure 1). If no reflux is found, then pro ceed with the dye disappearance test.
Dye Disappearance Test
1.Instill fluorescein into both eyes using a moistened fluorescein strip or a drop of sterile 2 % fluorescein solution.
2.Observe the tear film, preferably with a cobalt-blue light, to ensure that
fluorescein is visible in the preocular tear film of both eyes.
3.Wait 5 minutes. The patient may blink normally but should avoid wiping the eyes.
4.Use a cobalt-blue light to examine the tear meniscus.
a.The tear film should be clear, indicating complete disappearance of the fluorescein dye.
b.If the tears are still tinged yellow, the lacrimal outflow system has a functional or anatomic blockage (Figure 2).
c.Record any asymmetric clearance by indicating which side retains the dye longer.
5.For patients with delayed clearance of fluorescein, determine the level of occlusion by lacrimal probing and irrigation.
Figure 2 (Reprinted by permission from Orbit, Eyelids, and Lacrimal System. Basic and Clinical Science Course, Section 7. San Francisco: American Academy of Ophthalmology; 1996.)
209
Clinical Protocol 9.11
Conducting Tear Production
Tests for the Dry Eye
Schirmer I Test ("Schirmer Without Anesthetic")
1.Seat the patient in a dimmed room with the back of the head stabilized against the headrest of the examining chair.
2.Remove any excess moisture from the patient's eyelid margin with a facial tissue or cotton-tipped applicator. Do not instill any eyedrops into the eye before the test.
3.P'old a packaged, sterile filter paper strip at the indentation mark. To avoid contaminating the sterile strips, bend the round wick end of the test strips at the notch 120° before opening the pouch.
4.Open the pouch and remove a strip. Use the strip with the angled end for the right eye. Grasp the strip by the non-wick end to avoid contaminating the wick end with your fingertips.
5.Ask the patient to look up. Draw the lower lid gently downward, checking to make sure that the lid margin has been adequately dried with a cotton-tipped applicator. By convention, the strip with one corner cut off is used for the right eye.
6.Hook the rounded, bent end of the test strip over the lower eyelid margin of each eye and release the lower lid to hold the strip in place. The strip is typically placed at the junction of the inner two thirds and the outer one third of the eyelid margin. It should not touch the cornea. The notch should point toward the lateral canthus. Check to make sure that the short end of the strip is inserted all the way to the notch.
7.Ask the patient to gaze slightly above the midline with the eyelids open in subdued light (Figure 1). The patient may continue normal blinking. Patients are permitted to keep their eyes closed during the test, but squeezing should be discouraged.
:*...„
210
Figure 1
8.Note the time. After 5 minutes have elapsed, remove both strips.
9.Measure the distance between the indentation mark and the farthest extent of wetting. Standardized strips are packaged in an envelope with a millimeter scale. Do not include the bent wick end in the final measurement.
10.Record the result in the chart as follows: Schirmer I testing (without anesthetic): right eye: X mm/5 min; left eye: Y mm/5 min. If complete wetting occurs before 5 minutes, this time may be noted.
Basic Secretion Test ("Schirmer With Anesthetic")
1. Instill 1 drop of proparacaine 1% eyedrops into both eyes.
2.Wait 1 minute while the patient keeps both eyes closed.
3.Gently blot the cul-de-sac dry with a tissue or cotton swab.
4.Proceed with steps 1-10 of the Schirmer I test.
10
Slit-Lamp Biomicroscopy
T.
• he slit-lamp b-iomicroscope (more commonly and simply referred to as the slit lamp) is a unique instrument that permits magnified examination of transparent or translucent tissues of the eye in cross-section. The slit lamp enhances the external examination by allowing a binocular, stereoscopic view; a wide range of magnification (10x-500x); and illumination of variable shapes and intensities to highlight different aspects of ocular tissue. In addition to detailed examination and diagnostic tests of the anterior segment, the slit lamp, using specialized attachments and lenses, also permits applanation tonometry to measure intraocular pressure and examination of the posterior segment of the eye.
This chapter discusses the uses of the slit lamp in general and its parts and their functions in detail, including the principles of slit-lamp illumination. Various diagnostic and measurement techniques conducted with a slit lamp also are covered. Specific applications of slit-lamp techniques to the anterior segment examination are discussed in Chapter 11; detailed instructions
214 Chapter 10: Slit-Lamp Biomicroscopy
for performing Goldmann applanation tonometry with the slit lamp
appear in Chapter 12; instructions for indirect slit-lamp biomicroscopy
of the posterior segment are included in Chapter 13.
Uses of the Slit Lamp
The slit lamp is indispensable for the detailed examination of virtually all tissues of the eye and some of its adnexa. It is routinely used for examination of the anterior segment, which includes the anterior vitreous and those structures that are anterior to it. Most of the anterior segment tissues (except the anterior chamber angle and the posterior surface of the iris) are directly visible witii the slit lamp alone, without special variations in technique or nonstandard attachments or lenses. Optical constraints of the instrument and the eye to be examined prevent useful visualization of the angle of the anterior chamber and those structures that are posterior to the anterior vitreous unless various attachments or accessories are used (as discussed later in this chapter and in Chapters 11 and 13).
In addition to physical (visual) examination, the slit lamp is often used for tonometry, linear measurement of tissues or lesions, and ophthalmic photography. It can also be used in contact lens fitting, although this topic is beyond the scope of this manual.
Parts of the Slit Lamp
A typical slit lamp is illustrated in Figure 10.1. The Haag-Streit 900 model is shown because it is the most commonly encountered; several other fine slit lamps are available whose differences from the HaagStreit instrument are usually relatively minor or are easily mastered.
The slit-lamp biomicroscope consists of three principal portions: the viewing arm, containing the eyepiece and magnifying elements; the illumination arm, containing the light source and many of its controls; and the patient-positioning frame. These portions are connected to a base, which has a joystick that the examiner uses to move the viewing and illumination arms about. The entire unit is wired to a transformer power source on a supporting platform. The specific parts of the instrument are detailed below; numbers in parentheses correspond to the numbers in Figure 10.1.
Parts of the Slit Lamp |
2 1 3 |
Figure 10.1 Parts of the slit idinp y\ iddy-jtieit ^uuj.The numbers correspond to descriptions given in the text. (Courtesy Haag-Streit AG, Bern, Switzerland.)
The Viewing Arm
The examiner looks through a pair of eyepieces (1), also known as oculars, mounted on top of the viewing arm (2). A knurled focusing ring around each ocular can be twisted to suit the examiner's refractive error, and the two oculars can be pushed together or spread apart, much like the eyepieces of field binoculars, to accommodate the examiners interpupillary distance. The oculars are attached to a housing containing the instrument's magnification elements (3). Below this housing is a lever
* ! • (or sometimes a knob) for adjusting magnification (4).