1. 1 Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved. Assisting in Ophthalmology Chapter 37

2. 2 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.

3. 3 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.

4. 4 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.

5. 5 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.

6. 6 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.

7. 7 Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved. Disorders of the Eye  Refractive errors:  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.

8. 8 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

9. 9 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)

10. 10 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

11. 11 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

12. 12 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

13. 13 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)

14. 14 Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved. Types of Snellen Charts

15. 15 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

16. 16 Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved. Eye Irrigation

17. 17 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

18. 18 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

19. 19 Copyright © 2011, 2007, 2003, 1999 by Saunders, an imprint of Elsevier Inc. All rights reserved. THE END