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Chapter 48
Assessment of the Eye and Vision

Anatomy and Physiology Review
Layers of the eyeball: 3 layers or coatsSclera: External Layer: opaque tissue making up the white of the eye, and the transparent cornea on the front of the eye.Uvea: Middle Layer: is heavily pigmented. Consists of the Choroid (Many blood Vessels that supply nutrients to the eye), ciliary body(conets the choroid with the irisand secreates aquous humor), & iris controls amount of light entering the eye (is the colored portion of the external eye in the middle of the pupil). Retina: innermost layer a thin delicate structure made up of sensory receptors that transmit impluses to the optic nerve.

Anatomy and Physiology Review
Refractive structures and media: Light waves pass through these structors on the way through the eye. Each structorhas different ensity which casues light waves to bend (refract) to some degree to focus on images on the retina.Cornea: Clear layer that forms external coat on front of the eyeAqueous Humor: clear watery fluid that fills A&P chambers of eyeLens: circular convex structure, behind iris, in front to vitreous body, Normal is transparent. Lens bends the rays of light entering pupil so it can be focused on the retina.

Anatomy and Physiology Review

Vitreous Body: clear thick gel that fills the vitreous chamber (space between lens and retina) transmits light and maintains eye shape.Intraocular Pressure (IOP): Hollow organ, vitreous humor & aqueous humor keep shape and the pressure in the eye. Too low eye collapse, too high called glaucoma

Anatomy and Physiology Review
External structures:Canthus: place where two eyelids meet in the cornor of the eye.Conjunctiva: Muscle membranes of the eyesLacrimal Gland: upper outer part of each orbit Responsible for tearsPunctum opening at the nasal side of the lid ledges into the lacrimal duct and sac then nose through the nasolacrimal duct.Muscles, nerves, and blood vessels:LOOK AT PICTURE 1072

Anatomy and Physiology Review (Contd)

Eye

Refraction
Emmetropiathe perfect refraction of the eyeHyperopiaoccurs when the eye does not refract light enough (farsightedness)Myopiaoccurs when the eye overrefracts or overbends the light (nearsightedness)Astigmatisma refractive error caused by unevenly curved surfaces on or in the eye, especially of the cornea

Refraction (Contd) PG 1073

Pupillary Constriction
Miosis is pupillary constriction.Mydriasis is pupillary dilation.Accommodation is the process of maintaining a clear visual image when the gaze is shifted from a distant to a near object.Convergence: Turn both eyes inward toward the nose to ensure only a single image of close object is seen

Miosis and MydriasisPage 1074

Age-Related Structural Changes

Declining visual acuity: Decreased eye muscle toneEctropion: lower eyelid may relax and fall away fromfrom the eyeDry eyeArcus senilis: opque bluish white ring outer edgeof cornea caused by fat depositsCorneal changes: clarity and shapeChanges in color of scleraLess ability to dilate pupilMore light needed for reading

Nursing Interventions
Declining visual acuity: Lie about vision b/c afraid will lose driving privledgesStigma r/t to blindnessAnxietyProblems with ADLs and feeling of self worthAffects job, how support family, life sty;e

Arcus Senilis

Age-Related Functional Changes
Lens yellows.Accommodation is gradually lost. Lens hardens, shrinks & Loses elasticity and accommodate light decrases.Near point of vision increases (presbyopia). Hold things farther away to seeFar point decreases. Narrower field of visionColor perception decreases.Intraocular pressure increases.

Assessment
Patient historyNutrition historyFamily history and genetic riskCurrent health problems

Snellen Chart

Assessment
Near visionVisual fieldExtraocular muscle function Color vision

Diagnostic Tests
Imaging assessmentSlit-lamp examinationCorneal stainingTonometry: measures intraocular pressureNormal Pressure10-21mm hg

Self Tonometry at home test IOP

IOP Estimation

Ophthalmoscopy
Move toward pts eye from 12-15 inches away and to the side of his/her vision. As you direct the scope at the pupil you should get a red glare (red reflex) means reflection of the light on the retina. If no red glare means lens opacity or cloudy vitreous

Other Diagnostic Tests
Fluorescein angiography: Die in eye, rapid pictures detect retinal circulation deficitsElectroretinography: retina response to light stimulation. Detect blood vessle damage

Chapter 48
NCLEX TIME

Question 1
Which circumstance places the patient at the greatest risk for developing vision disturbances?

History of working with computerAdvanced ageHistory of diabetes mellitus Previous employment as a road construction worker

Question 2
What characteristic would the nurse expect to see with age-related changes in an older patients eyes?

Yellowing of the sclera Retinal atrophyColor blindnessEarly-onset glaucoma

Question 3
Which is a priority nursing intervention when providing care to an older patient who has problems with vision?

Review the medication administration record for artificial tearsReview medications before administrationEnsure adequate, nonglare lighting in the patients room Provide written and verbal instruction for nursing education interventions

Question 4
In performing a psychosocial assessment of a patient who has recently experienced vision changes, the nurse should:

Provide the patient with a list of services for the visually impaired.Meet with family members or significant others to determine if the patient can still perform his ADLs.Ask the patient how he feels about the changes in his vision and the effectiveness of his coping methods. Ask the patient if he has made appropriate adjustments in his lifestyle to accommodate his vision changes.

Question 5
What is an appropriate expected outcome for the patient who has undergone an examination of the eye using fluorescein angiography?

Administering mydriatic eye drops for 1 week Drinking fluids to eliminate the dye Appearance of bright redcolored urine until the dye is excreted Staining of the skin for up to 1 week after the test

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Answer: CRationale: Certain systemic diseases increase the risk for developing visual problems. Diabetes mellitus and hypertension can have serious adverse effects on vision. Working with a computer can cause eye strain. Working outside can result in too much exposure to ultraviolet rays if proper eye protection is not worn. Advanced age also influences vision, but environmental factors and diseases impact vision changes associated with advanced age.
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Answer: ARationale: Fatty deposits cause the sclera to develop a yellowish tinge. Retinal atrophy, color blindness, and early-onset glaucoma are not expected age-related changes in the eyes.
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Answer: CRationale: Several changes in the eye that occur with aging alter vision, increasing the risk for tripping or falling. Good lighting is necessary for best vision. Color discrimination can be difficult for older patients, so medication education should include names and indications of medications, but use caution when instructing on color. Verbal and written education provide reinforcement for new information. With aging, the eye dries and artificial tears or normal saline drops can help relieve eye irritation.
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Answer: CRationale: A patient who has experienced changes in visual perception may be anxious or fearful about a possible loss of vision. Visual impairment services are probably not necessary at this early stage. The patients ability to perform ADLs should be assessed first, and directly from the patient (not family members).
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Answer: BRationale: After the test, encourage the patient to drink fluids to help eliminate the dye. Emphasize that any yellow or green staining of the skin will disappear in a few hours. After the test, the urine will be bright green until the dye is excreted. Instruct the patient to avoid direct sunlight until pupils are no longer dilated