Download Assisting in Ophthalmology

Assisting in Ophthalmology
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Learning Objectives
• Define, spell, and pronounce the terms listed
in the vocabulary.
• Apply critical thinking skills in performing
patient assessment and care.
• Explain the differences among an
ophthalmologist, optometrist, and optician.
• Identify the anatomic structures of the eye.
• Describe how vision occurs.
• Differentiate among the major types of
refractive errors.
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Learning Objectives
• Summarize typical disorders of the eye.
• Define the various diagnostic procedures for the
eye.
• Conduct a vision acuity test using the Snellen
chart.
• Assess color acuity.
• Illustrate the purpose of eye irrigations and the
instillation of medication.
• Properly irrigate a patient’s eyes.
• Accurately instill eye medication.
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Examination of the Eye
• The ophthalmologist is a medical physician
specializing in the diagnosis and treatment of
the eye.
• The optometrist examines and treats visual
defects.
• An optician fills prescriptions for corrective
lenses.
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Anatomy and Physiology of the Eye
• The anatomy of the eye begins with the outer
covering, the conjunctiva, and the three layers of
tissue: sclera, choroid, and retina.
• The retina in the inner layer of the eye is where light
rays are converted into nervous energy for
interpretation by the brain.
• The lens is a transparent body that helps focus light
after it passes through the cornea.
• The posterior cavity contains vitreous humor and the
anterior cavity contains aqueous humor.
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Vision
• Vision begins with the passage of light through the
cornea, where it is refracted and then passes through
the aqueous humor and pupil into the lens.
• The ciliary muscle adjusts the curvature of the lens to
refract the light rays so they pass into the retina,
triggering the photoreceptor cells of the rods and
cones.
• Light energy is then converted into an electrical
impulse, which is sent through the optic nerve to the
brain, where interpretation occurs.
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Disorders of the Eye
• Refractive errors:
–
–
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–
Hyperopia
Myopia
Presbyopia
Astigmatism
• All are caused by a problem with bending light
so it can be accurately focused on the retina.
• They are usually caused by defects in the shape
of the eyeball and can be corrected with
glasses, contact lenses, or surgery.
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Signs and Symptoms of Refractive
Errors
•
•
•
•
Squinting
Frequent rubbing of the eyes
Headaches
Blurring of vision and/or fading of words at
reading level
• Some refractive errors are familial in nature
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Treatment of Refractive Errors
•
•
•
•
Eyeglasses and contact lenses
Photorefractive Keratectomy (PRK)
Laser-Assisted In-Situ Keratomileusis (LASIK)
Laser-Assisted Epithelial Keratomileusis
(LASEK)
• Conductive Keratoplasty (CK)
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Cataracts
• Cataracts – opaque changes in the lens;
cause blurred, less acute vision. Diagnosis
made with a slit lamp
• Treatment – outpatient surgical removal of
lens and placement of artificial lens
– Extracapsular extraction removes cataract in
one piece
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Glaucoma
• Aqueous humor builds up, increasing
intraocular pressure and decreasing blood
supply to retina and optic nerve
• Signs and symptoms – frequent need to change
eyeglass prescriptions, loss of peripheral vision,
mild headaches, and impaired adaptation to the
dark
• Diagnosis – tonometer and eye examination
• Treatment – miotic drops, beta-blockers, or
laser surgery
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Macular Degeneration
• Macula lutea is part of the retina and
defines the center of the field of vision
• Progressive deterioration of macula lutea
causes progressive loss of central vision
• Age-related; no cure
– antioxidants including carotene, selenium, zinc,
and vitamins C and E may prevent the
condition or slow its progress
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Distance Visual Acuity
• Distance visual acuity is typically assessed using
a Snellen chart.
– May use E chart, pediatric picture chart, or alphabet
chart
– Patient stands 20 feet from chart at eye level
– Eyes tested with corrective lenses worn
– Record results as fraction with 20 feet on top
– Both eyes remain open during the examination; no
squinting or straining
– Abbreviations: OD (right), OS (left), OU (both)
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Types of Snellen Charts
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Treatment Procedures: Irrigations
• Eye irrigations relieve inflammation, remove
drainage, dilute chemicals, or wash away
foreign bodies.
• Sterile technique and equipment must be
used to avoid contamination.
• Pour solution from inner canthus out, with
head tilted toward the affected eye.
• Procedure 37-3
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Eye Irrigation
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Ophthalmic Medication Procedures
• Medication may be instilled into the eye for treatment of an
infection, to soothe an eye irritation, to anesthetize the eye,
or to dilate the pupils before examination or treatment.
• Eye drops—do not touch anything with applicator; insert
into lower conjunctival sac while patient looks up.
• Eye ung—sterile procedure; apply thin ribbon of medication
in lower conjunctival sac.
• Patient should gently close eye after application and rotate
eyeball to disperse medication.
• Refer to Table 37-2
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.
Asepsis and Ophthalmic Medications
• A major concern in ophthalmologic procedures is the
contamination of eye medication applicators
• Use of stock ophthalmic medications is discouraged
• Sterility of eye medications is critical
• Newly opened sterile solutions should be used for
each patient and either disposed of after instillation
or given to the patient for home use
• All instruments used for the removal of a foreign body
in the eye should be sterile
Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved.