Assisting with Eye and Ear Care Lesson 1: The Study of the Eye 39 Assisting with Eye and Ear Care Lesson 1: The Study of the Eye

Lesson Objectives Upon completion of this lesson, students should be able to … Define the terms to learn in this chapter. Explain procedures to evaluate distance vision, color vision, near vision, and contrast sensitivity. Explain procedures to irrigate the eye and instill eye medications. Name three causes of blindness.

Lesson Objectives Explain the procedure for assisting visually-impaired patients to prepare for physical examinations. List and explain five age-related changes in the eye.

Structures of the Eye 4

Anatomy and Physiology of the Eye 5

Critical Thinking Question If you were having vision problems would you go to an ophthalmologist, an optometrist, or an optician? Explain.

Ophthalmologist Medical doctor Performs eye examinations and eye surgery Prescribes medications, eyeglasses, and contact lenses

Doctor of Optometry (OD) Also referred to as an optometrist Performs eye examinations, prescribes medications, and writes prescriptions for eyeglasses and contact lenses

Optician Grinds lenses and prepares eyeglasses and contact lenses Completes a 2- to 4-year apprenticeship Licensure required by some states 9

Otoscope Used to examine the tympanum or myringa for signs of infection and inflammation Tympanum or myringa are medical terms for the eardrum

Ophthalmoscope Used to view inner parts of the eye Physician positions the ophthalmoscope so light penetrates the pupil of the patient’s eye and screens for retinal damage and vascular problems

Evaluating the Status of the Patient’s Pupils PERRLA is an acronym that stands for Pupils Equal, Round, React to Light and Accommodation and focus on objects at different distances Normally the pupils of the eyes are the same size and change or accommodate when a beam of light is focused on the eye and is then removed Injuries to the brain may result in the patient having pupils of unequal size

Visual Acuity Normal visual acuity, or clearness of vision, is referred to as 20/20 vision, which means the eye should see an object 20 feet away clearly. Errors of refraction occur when the eyeball is: Too long Too short The lens loses its elasticity The lens or cornea has an irregular curvature

Refractive Errors

Myopia Also known as nearsightedness When the eye sees near objects well but distant objects appear blurry Occurs either because the eyeball is too long or because the lens is too thick, and the light rays do not reach the retina Myopic eye requires a concave lens to correct vision

Myopia

Hyperopia Also known as farsightedness When the eyes see distant objects well, but near objects are blurry In this case, the eyeball is too short or the lens too thin The hyperopic eye requires a convex lens to correct the visual defect

Hyperopia

Refractive Errors Presbyopia Astigmatism Term associated with farsightedness that occurs with aging The lens loses its elasticity and glasses are needed for reading Astigmatism The lenses or cornea are uneven and light is not bent or refracted evenly Images may be clear in the center and blurry at the outer edges of the visual field

Strabismus Caused by weakness in the external eye muscles resulting in the eyes looking in different directions Normally the eyes focus on a subject in coordination; otherwise double vision occurs Children with strabismus appear “cross-eyed” and may need to wear a patch over the “good” eye to strengthen the weaker eye

Strabismus It is important that treatment begin at an early age to prevent permanent damage to the eye If the patch and exercise plan are ineffective, surgery on the eye muscle may be necessary

Snellen Chart Largest symbols are on the top line and each line after is of decreasing size Person with normal vision can read the top line at 200 feet To the right of each line is a ratio indicating that a person with normal vision could read at decreasing distances of 100, 70, 50, 40, 30, and 20 feet

Snellen Chart A result of 20/20 vision means that a person with normal distance acuity could read that line at a distance of 20 feet For preschool children or patients who are illiterate or have a language barrier, the Snellen E, the Landolt C, or pictorial charts are used

Snellen Chart With the Snellen E chart, have the patient demonstrate by pointing his or her finger in the direction the E is pointing prior to testing so as to determine whether or not the patient can follow directions When dealing with young children, it may be helpful to make a game of it, showing them how to hold their hands to illustrate which direction the E is facing

Eye Abbreviations Abbreviation for the right eye is OD (oculus dexter) Abbreviation for the left eye it is OS (oculus sinister) Abbreviation for both eyes is OU (oculus uterque) Although these abbreviations are used, the Institute for Safe Medication Practices (ISMP) recommends that the complete words must be used to avoid misinterpretation and error.

The Snellen Eye Chart

Steps for Using the Snellen Chart Assemble equipment Review physician’s order Perform hand hygiene and identify the patient Explain the procedure Determine the patient’s ability to recognize letters – If the patient is unable to read letters, use the necessary chart to accommodate the patient’s abilities

Steps for Using the Snellen Chart Place the patient 20 feet from the chart, either seated or standing, as long as the Snellen eye chart is at eye level Following office policies (regarding which eye to test first) have the patient cover the other eye with a cup or occluder The occluder should be held in such a way as not to interfere with the normal position of a patient’s glasses

Steps for Using the Snellen Chart Instruct the patient to keep both eyes open even though one eye is covered Have patient read the lines with both eyes first at a distance of 20 feet Use pointer and point to letters or appropriate symbols in random order Starting with the 20/70 line ask the patient to identify each line and proceed down the chart to the last line the patient can read without error

Steps for Using the Snellen Chart Observe for signs of squinting or tilting the head which indicate difficulty identifying letters Record the ratio numbers adjacent to the line the patient can read without error If there is an error, note it (e.g., Right eye 20/40 –1 or Right eye 20/40 –1 with correction; meaning glasses were worn during testing)

Steps for Using the Snellen Chart ISMP recommends using words instead of abbreviations of eye designations to avoid misinterpretation Follow office protocol regarding charting Repeat the procedure with the other eye and record the result, noting any unusual symptoms such as squinting, or blinking excessively

Steps for Using the Snellen Chart Clean the occluder with gauze and alcohol Remove gloves and perform hand hygiene Document the results accurately

Steps to Test for Near Vision Acuity Using the Jaeger Card Patient reads a card held at normal reading distance (14 to 16 inches) Card has a series of paragraphs decreasing in size of print with a number above each Number one (J1) is next to the paragraph with the smallest text and as the text becomes larger the number increases Paragraph J2 represents 20/20 vision

Steps to Test for Near Vision Acuity Using the Jaeger Card Patient’s result is the number above the last paragraph he or she can read easily This test should always be performed in a well-lit room

Color Vision Impairment The inability to distinguish colors of the spectrum distinctly Defects in color vision are either congenital or inherited, or acquired through disease or injury Congenital means the individual was born with the condition – more prevalent in males

Color Vision Impairment It is important to test for color vision defects because changes in color vision may indicate diseases of the retina, optic nerve, or thyroid The most common type of color vision defect, which is inherited, is the inability to distinguish red and green

The Ishihara Test Screening for color vision acuity Printed card or booklet with a single color-dot illustration containing a number, or curved lines and shapes Patient is shown 14 color plates or pages and must correctly identify 10 to be considered to have color vision within normal limits Ishihara Booklet or cards should be stored out of direct light to prevent fading of the color plates

The Ishihara Test

Contrast Sensitivity Measures the patient’s ability to distinguish faint differences in shades of grey Several new testing procedures are used to test for contrast sensitivity – Vistech Consultant system and the Pelli-Robson chart

Contrast Sensitivity To perform a procedure for contrast sensitivity, adhere to manufacturer’s directions and observe the usual procedural steps for appropriate patient care Contrast sensitivity is affected by most major eye conditions such as macular degeneration, cataracts, glaucoma, and diabetic retinopathy

Procedures and Diagnostic Tests Related to the Eye Corneal transplant: The surgical process of transferring the cornea from a donor to a patient Electroretinogram: A record of the electrical response of the retina to light stimulation

Fluorescein Angiography Process of injecting fluorescein (a dye) followed by a series of photographs of the retina through dilated pupils Provides diagnostic information about the blood flow in the retina Detects vascular changes in diabetic and hypertensive retinopathy Identifies lesions in the macular area of the retina, determining if there is detachment of the retina

Procedures and Diagnostic Tests Related to the Eye Gonioscopy: Use of gonioscope to examine the anterior chamber of the eye to determine ocular motility and rotation Keratometry: Measurement of the cornea using an instrument called a keratometer Keratoplasty: Surgical repair of the cornea (corneal transplant)

Procedures and Diagnostic Tests Related to the Eye Laser surgery: Surgical procedure performed with a laser handpiece that transfers light into intense, small beams capable of destroying or fixing tissue in place Optomyometer: An instrument used to measure the strength of the muscles of the eye

Procedures and Diagnostic Tests Related to the Eye Phacoemulsification: The process of using ultrasonic vibrations to disintegrate a cataract A needle is inserted through a small incision and the disintegrated cataract is aspirated The ophthalmic surgeon uses a small, self-sealing scleral-tunnel incision

Radial Keratotomy A surgical procedure that may be performed to correct nearsightedness (myopia) Delicate spoke-like incisions are made in the cornea to flatten it, thereby shortening the eyeball so that light reaches the retina Not all patients have their vision improved, and complications could lead to blindness

Slit-Lamp Microscopy The instrument used in ophthalmology for examining the posterior surface of the cornea

Tonometry Measurement of intraocular pressure (IOP) of the eye using a tonometer to check for glaucoma An air puff tonometer records the cornea’s resistance to pressure

Procedures and Diagnostic Tests Related to the Eye Visual acuity: Measurements of the sharpness of a patient’s vision Usually a Snellen eye chart is used and the patient identifies letters from a distance of 20 feet Vitrectomy: A surgical procedure for replacing the contents of the vitreous chamber of the eye

Procedures and Diagnostic Tests Related to the Eye Near-Vision Acuity Chart

Contrast Sensitivity Chart

Eye Irrigation Irrigation or lavage (rinsing) of the eye is necessary to remove foreign substances or chemicals Requires the use of sterile technique and equipment Never try to remove a foreign object from the eye using an applicator stick, as this may cause corneal abrasions

Eye Irrigation

Steps to Irrigating the Eye Identify the patient and explain the procedure Review the physician’s order Assemble the equipment Check the label of the irrigating solution three times to make sure it is the correct solution and the concentration ordered by the physician

Steps to Irrigating the Eye Check the expiration date on the label to make sure the solution has not expired The solution should be brought to room temperature by wrapping the bottle in a dry heating pad or standing the bottle in a warm water bath Perform hand hygiene and apply gloves Ask the patient which position he or she would prefer, sitting or lying down

Steps to Irrigating the Eye Place a towel over the patient’s shoulder If both eyes are to be irrigated, then two separate sets of equipment must be used to prevent cross-infection Open the irrigating solution and fill the syringe Ask the patient to tilt the head to the affected side if seated, and hold the basin

Steps to Irrigating the Eye Open the patient’s eye using the index finger and thumb of the nondominant hand Hold a tissue on the patient’s cheekbone below the lower lid and pull down and expose the conjunctiva Hold the syringe ½ inch from the eye Gently irrigate from inner to outer canthus, or the corner of eye, aiming at the lower conjunctiva

Steps to Irrigating the Eye Continue irrigating until the solution is used up Dry the area around the eye with sterile gauze Dispose of the equipment properly Perform hand hygiene Document information in the patient’s chart in the appropriate manner

Instillation of Eye Medications Only ophthalmic or optic medications can be used in the eye, and they must be sterile Important to reinforce the need for sterile medications with patients Encourage patients to discard eye medications when the prescribed treatment time has been completed Eye medications should never be shared with others or even used in their other eye if treatment is needed

Steps for the Instillation of Eye Medication Perform hand hygiene Check the physician’s orders Identify the patient, introduce yourself, and explain the procedure Check the name of the medication, expiration date, and concentration three times Ask the patient if he or she has any known allergies to the medication

Steps for the Instillation of Eye Medication Give the patient a tissue to blot cheeks Put on gloves Position the patient with head tilted back and looking up Pull down the lower eyelid exposing the conjunctiva Place the dropper about ½ inch above the eyeball with the dominant hand

Steps for the Instillation of Eye Medication Insert the proper amount of drops to the center of the conjunctiva, or if ointment is used, apply as a thin strip from inner to outer canthus Do not touch the dropper or ointment tube to the eye Ask the patient to gently close the eye and rotate the eyeball

Steps for the Instillation of Eye Medication Using sterile gauze, dry the excess medication from the inner canthus to the outer canthus Explain to the patient that vision may be blurry Clean the area and dispose of unused medication Remove gloves and perform hand hygiene Document the procedure appropriately

Steps for the Instillation of Eye Medication

Questions? 65