Ординатура / Офтальмология / Английские материалы / Practical Ophthalmology A Manual for the Beginning Ophthalmology Residents 4th edition_Wilson_1996
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posterior pole (2 through 6), ending at the macula (7). This sequence requires redirecting the patient's gaze in these directions using verbal instructions or a target such as a fixation light or your fingertip. Direct the patient's gaze into primary position using a fixation target after the central fundus examination is complete.
10.To examine the vitreous cavity, angle the slit beam about 10°-20° from the axis of observation. Move the condensing lens slightly toward you to examine the vitreous. Having the patient follow a target that moves a few degrees can help you to see strands of the vitreous humor. To help visualize opacities in the posterior vitreous, move the slit-lamp joystick and illumination arm to produce alternating direct illumination and retroillumination. Vitreous examination can also be enhanced by a small circular rotation of the condensing lens in one plane.
11.To examine the peripheral vitreous and fundus, reduce the illuminationobservation angle and rotate the slit beam to the meridian being observed. Scleral depression can be performed to bring the equatorial fundus into view.
Performing Hruby Lens Biomicroscopy
1.Assume standard patient and examiner positions at the slit-lamp biomicroscope (see Chapter 10).
2.Ensure that the patient's pupils are fully dilated.
3.Set the slit-lamp magnification to lOx or 16x.
4.Focus and center a slit beam about 4 mm wide onto the corneal surface at the central, nearly coaxial position. Use medium-bright light intensity that the patient can easily tolerate.
5.Move the Hruby lens into position as follows:
a. If attached on the top of the slit lamp, allow the bar to slide toward the headrest and rotate the lens so it clicks in place.
b. If the lens is on a hinged side arm, put the arm into the groove on the slit-lamp housing, making sure the piano side of the lens faces the patient and the concave side is toward you.
6.Direct the patient's gaze into primary position using the fixation light on the instrument or other target.
Figure 2A |
Figure 2B |
8.Angle the contact lens onto the globe from below and instruct the patient to look straight ahead (Figures 2A, 2B). Release the patient's lids and allow the contact lens to hold the lids apart. Switch hands, if necessary, to hold the contact lens in your hand closest to the patient's eye (eg, your left hand for die patient's right eye) so your arm does not interfere with using die slit lamp.
9.If there are any air bubbles caught between the contact lens and the cornea, slightly tilt die lens to allow diem to float out. Allow die contact lens to sit gently on die cornea, avoiding unnecessary pressure on die lens by your fingers that keep the lens steady.
10.Use die joystick to focus die slit lamp toward the patient. Begin with the illumination arm in the coaxial position and examine the posterior pole. Tilt the lens slightly to maneuver light reflections from the lens surface away from die central viewing area.
11. If a diree-mirror lens is used, positioa die light source on the same side as the side of the eye being examined so that the light beam bounces off die mirror. Begin with die largest, least-angled mirror to examine die area around the posterior pole.
12. To examine the adjacent fundus area, twirl the lens on the eye witii a dialing motion for 1 or 2 clock hours. Realign die slit beam to view die
, new fundus area.
13.After circumferential examination of the fundus with one mirror, repeat with the other two mirrors to examine the equatorial and peripheral
14
Ophthalmic Emergencies
• his chapter gives a brief overview of common emergencies encountered by beginning ophthalmology residents on call, including how to evaluate the emergency room patient and how to treat common emergencies; it is not exhaustive in coverage. Opinions differ with regard to certain aspects of therapeutics (such as the management of hyphemas), but the information given should serve as a useful base upon which to build further knowledge as your training progresses. The treatments for most of the conditions listed in this chapter are evolving and, in many cases, controversial; other sources of information must be consulted on an ongoing basis. Some entities covered here are not medically urgent but are often seen in the emergency room.
The diagnosis and management of ophthalmic emergencies require a disciplined, methodical approach to ensure proper care and to avoid mistakes. The need for a quick examination of an emergency patient should not preclude thoroughness. Conducting a thorough evaluation requires first-hand knowledge of
3^4 Chapter 14: Ophthalmic Emergencies
the various steps of the medical history and physical examination.
Proper documentation, timely treatment, and meticulous attention to
details are necessary for optimal medical care as well as for medicolegal
reasons (see Chapter 3, "History Taking"). If you are uncertain of how
to handle an ophthalmic emergency, you are obligated not only to
quickly seek the help of an experienced ophthalmologist but also to
obtain appropriate consultations from other medical specialists as the
situation demands.
Emergency Equipment and General Evaluation
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Ideally, patients arriving through the emergency room should be eval- |
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uated in the eye clinic or in an examining room complete with a wall |
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chart, slit lamp, and indirect ophthalmoscope. This will not always be |
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possible, but some portable equipment must be made available for |
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evaluation of emergency patients. To meet this need, you may want to |
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prepare a bag containing essential equipment and supplies, including |
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the following: |
•Light source (eg, muscle light, small flashlight)
•Direct ophthalmoscope
•Near vision card
•Pinhole occluder
•+2.5 D lens and +20 D lens
•Small toys or other pediatric fixation targets
•Fluorescein strips
ijiv , • Eyelid retractor
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• Small ruler (with millimeters) |
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• Certain ophthalmic medications such as proparacaine |
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(Ophthaine), timolol maleate (Timoptic) 0.5%, pilocarpine 2%, |
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and tropicamide 1% |
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Other, less portable equipment, such as an indirect ophthalmoscope |
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and slit lamp with Goldmann tonometer, is usually available in exami- |
Emergency Equipment and General Evaluation |
355 |
nation rooms, although including a Schiotz tonometer or Tonopen in the emergency bag is a good idea.
Evaluation of patients with emergent eye injuries or disorders begins with a thorough history. Always inquire about the patient's vision before the injury or disorder. Knowing that a patient presenting with blunt trauma and 20/200 vision also has a history of amblyopia drastically changes the clinical picture. However, never defer treatment of a true ocular emergency (chemical burn, central retinal artery occlusion, or acute angle-closure glaucoma) to take the history. In all emergency cases, the history should be tailored to suit the nature of the disorder. If surgical intervention is a possibility, ask about the patient's last oral intake and withhold further oral intake until a therapeutic decision is made. Also, ask about the last tetanus booster in all cases of penetrating trauma.
Like the history, the ophthalmic examination is streamlined to accommodate the emergency patient. As the first step, the visual acuity must be determined as soon after presentation as possible, before a condition (corneal opacity, hyphema, lid swelling) evolves to preclude measurement. To assess acuity in the emergency setting, it is useful to have a pinhole occluder on hand to help account for refractive errors, a +2.5 D lens to help account for presbyopia, and a near reading card. If the patient's vision is greatly impaired, color vision using bright red and green bottle caps and light projection to all quadrants should be documented. The pertinent aspects of the external, motility, confrontation visual fields, pupillary, and anterior segment examinations, tonometry, and ophthalmoscopy are then performed in that order. If significant head trauma exists, defer dilation of the pupils to preserve the pupillary reaction for periodic neurologic evaluations. Maneuvers that apply pressure to the globe, such as scleral depression and Schiotz tonometry, should not be performed on patients with potentially ruptured globes or hyphema.
Pediatric Evaluation
Special techniques are needed for the evaluation of children in the emergency setting. Patience, tact, and sensitivity to the concerns of parents are essential. To avoid prompting crying spells in pediatric patients, try to gather as much information as possible by careful observation without touching the child. Avoid threatening demeanor and gestures—keep a low profile during the evaluation, if possible, moving about slowly and deliberately. Tovs and interesting fixation targets may simplify pediatric examinations, and infants mav be easier to evaluate if given a pacifier or bottle to quiet them down. However, withhold oral intake if surgical repair is contemplated.