Sensory System Testing: Vision

Sensory System Testing and Interventions

• Tonometry measures intraocular pressure (IOP)

• Normal IOP is 10-21 mmHg

• Report IOP readings > 21 mmHg

• Glaucoma and trauma can cause increased IOP

• Coughing and sneezing are other examples that can cause increased IOP

• Nursing intervention for increased IOP > 21 involves applying drops (medications)

• Increased aqueous humor production by the ciliary process can cause increased IOP

Snellen Chart

• Used for visual activity testing

• Normal visual acuity is 20/20

Color Vision Testing

• Determines the ability to distinguish colors

• Ishihara test is used for color vision testing

• Patients identify numbers or paths formed by patterns of dots in the Ishihara test

Slit-Lamp Exam

• Microscope with intense narrow light used in eye exams

• Provides magnification of the eye to enhance visualization of different parts

• Helps visualize and diagnose corneal damage, cataracts, and macular degeneration

Perimetry Testing

• Visual field testing

• Detects changes in central and peripheral vision

• Stroke, glaucoma, and brain tumors can cause changes in central and peripheral vision

• During perimetry testing the patient looks inside a perimeter, a bowl-shaped instrument

• While looking into the perimeter a light flashes, the patient presses a button each time the light is seen

• A computer records the data and provides a printout of where the flashes of light aren't seen

Fluorescein Angiography Teaching

• Patient may experience temporary discoloration of urine and skin after the procedure

A-scan Ultrasonography

• Determines the correct power of a lens implant before cataract surgery

Tonometry Healthcare Provider Notification

• Notify the healthcare provider if a patient undergoing tonometry testing with an IOP value of 25 mmHg

Perimetry Testing Explanation

• Perimetry testing is used to detect changes in central and peripheral vision

Instructions for Pupil-Dilating Drops

• The patient may experience photophobia and blurred near vision

Amsler Grid Test Benefit

• Patients with suspected macular degeneration benefit from an Amsler Grid Test

Ishihara Test Purpose

• The Ishihara test is used to identify the ability to distinguish different colors

Diagnostic Test for Suspected Glaucoma

• Tonometry is the most appropriate diagnostic test for confirming increased intraocular pressure in patients with symptoms of suspected glaucoma

B-scan Ultrasonography Purpose

• B-scan ultrasonography assesses for intraocular tumors and foreign bodies

Interpreting Snellen Chart Results

• If a patient's vision is recorded as 20/50, they can see objects at 20 feet that a normal person sees at 50 feet

Nursing Considerations for Fluorescein Angiography

• Monitor for extravasation of the IV contrast

• Educate the patient their urine and skin may be temporarily discolored

• Monitor for nausea and vomiting

Factors Contributing to Increased IOP

• Coughing
• Sneezing
• Increased aqueous humor production
• Excessive eye rubbing

Slit-Lamp Examination Detection

• Cataracts
• Macular degeneration
• Retinal detachment
• Corneal damage

Snellen Chart Education Points

• Assesses visual acuity

• A result of 20/20 indicates normal vision

• The patient should remove corrective lenses before the test

• Patient stands 20 feet away from the chart

Conditions Causing Changes in Central and Peripheral Vision

• Stroke
• Glaucoma
• Brain tumors
• Macular degeneration

Immediate Intervention for Amsler Grid Test

• A patient who states, "Some lines on the grid look wavy and distorted" needs immediate intervention

Tonometry Teaching Points

• If IOP is greater than 21 mmHg, it does not automatically mean the patient is diagnosed with glaucoma

Diagnostic Test for Suspected Diabetic Retinopathy

• Fluorescein angiography is most useful for a patient with suspected diabetic retinopathy

Appropriate Nursing Action for B-scan Ultrasonography

• Explain that the test is used to detect intraocular pathologic conditions

Diagnostic Test Priority for Sudden Loss of Peripheral Vision

• Perimetry testing is the priority assessment

Retinal Detachment

• Medical emergency involving painless separation of the retina from the epithelium with fluid accumulation

Risk Factors

• Age
• Cataract surgery
• Eye trauma
• History of severe myopia

Signs and Symptoms

• Sudden, painless onset
• Bright flashes of light (photopsia)
• Floaters
• Cobwebs
• Hair nets or rings

Detached Retina

• Vision described "like a curtain"

Diagnostics

• Visual acuity testing
• Ophthalmologic exam
• Ultrasound if retina cannot be visualized

Glaucoma

• Disturbance of optic nerve's functional or structural integrity

• Decreased fluid drainage or increased fluid secretion increases IOP

• Can cause atrophic changes and visual effects

Primary Open-Angle Glaucoma (POAG)

• Most common type, affecting both eyes

• Develops slowly, with gradual loss of visual fields that may go unnoticed due to central vision unaffected

• Decreased aqueous humor outflow due to blockages in the eye's drainage system

• Gradual rise in IOP

Late Symptoms

• Halos
• Loss of peripheral vision
• Decreased sensory perception

Characteristics

• Asymptomatic without pain/pressure

Treatment

• Timolol, lopidine, and pilocarpine

• Beta-adrenergic blocking agents such as timolol ophthalmic drops are used

• Can have additive effects with oral systemic beta blockers

• Inquire about medications and medical history (heart conditions and asthma/COPD)

• Aqueous humor cannot drain from the eye, causing pressure damage to the optic nerve

Acute Angle-Closure Glaucoma (AACG)

• Sudden onset and constitutes an emergency

• Forward displacement of iris presses against the cornea

• Closes the chamber angle and prevents outflow of aqueous humor

Signs and Symptoms

• Rapid, increased IOP > 50
• Severe pain

Diagnostics

• Tonometry measures IOP

Treatment

• Ophthalmic drops such as pilocarpine and IV agents such as mannitol can be administered

• Ocular emergency, thus IV medication will have a rapid effect

Cataracts

• Opacity in the lens of an eye impairs vision

• Can be unilateral or bilateral

Causes

• Age-related is most common
• Smoking
• Trauma
• Alcohol use
• Radiation
• Drugs
• Diabetes mellitus (DM)

Signs and Symptoms

• Decrease in vision and glare
• Abnormal color perception
• White pupil

Diagnostics

• Slit lamp exam

Treatment

• No cure other than surgical removal

Non-Surgical Treatment

• Changing eyewear
• Visual magnifying glass and light

Surgical Treatment

• Pre-op local anesthesia

• Assess elderly patient medication list

• Cycloplegics produce paralysis of accommodation, tropicamide (Mydriacyl), cyclopentolate (Cyclogyl)

• Teach the patient to wear dark glasses to prevent photophobia

• Monitor for systemic signs of toxicity which may include tachycardia and central nervous system effects

Post-Op Care

• Avoid bright lights (sunglasses) and watch for infection

• Avoid activities that increase IOP

• Bending at the waist, coughing, sneezing, and heavy lifting should be avoided

Importance of Follow-Up

• Assess visual acuity and chamber depth

Normal Findings

• Mild itching and bloodshot appearance

Abnormal Findings

• Severe pain
• Decreased vision, s/s of infection

Assessment

• Infection and pain

Nursing Considerations

• At risk for falls and eye patch use required
• May take 1-2 weeks to regain vision, and initial modification of activities may be required

Notification to Surgeon

• If the nurse observes purulent drainage from the affected eye

Macular Degeneration

• Deterioration of the macula (back of eye)

Dry Macular Degeneration

• More common and gradual; Progressive & painless

Wet Macular Degeneration

• More severe and rapid onset and leads to blindness

Causes

• Genetics
• High CRP levels
• Smoking
• Hypertension (HTN)

Common Cause

• Most common cause of irreversible central vision loss >60

Signs and Symptoms

• Blurred and darkened vision

• Scotomas (blind spots in the visual field)

• Metamorphosia (distortion of vision)

Diagnostics

• Visual acuity test and fluorescein IV angiography

Treatment

• Directed at prevention for further vision loss and cannot restore vision

• Limited options for wet macular degeneration includes medications injected directly into the vitreous cavity, Lucentis, Avastin, eylea, and Macugen, which prevent further vision loss

Side Effects

• Blurred vision, eye irritation, eye pain, and photosensitivity

• Photodynamic therapy and nutritional factors include Vitamin C, beta-carotene, Vitamin E, and smoking cessation

Nursing Care

• Smoking cessation

• Ensure safety

• Encourage follow-up care

• Provide psychological support and nutrition info

Television and Macular Degeneration

• Place the television where for best visualization of the screen; on either side of the client

Meniere’s Disease

• Progressive disorder involving the accumulation of endolymph in the membranous

Signs and Symptoms

• Vertigo
• Tinnitus
• Ear pressure or fullness
• Drop attack

Patient Population

• Women aged 30-60

Treatment

• There is no cure, treatments aim to reduce the number and severity of vertigo attacks

• While the cause is unknown but affects one eye

Acute Attack Management

• Corticosteroids
• Antihistamine (diphenhydramine)
• Anticholinergics (atropine, scopolamine)
• Benzoos (lorazepam) can decrease the abnormal sensation and lessen N/V

Between Attacks

• Diuretics
• Steroids
• Low-sodium diet
• Stress reduction

Surgery

• Decompression of the endolymphatic sac and shunting

Nursing Care

• Focused on SAFETY, which avoids falls and injuries

• Preventative measures include a dark & quiet room, no sudden movements (move head slowly), sit or lie down at the onset of dizziness, no swimming, and avoiding being in high places

Interprofessional Care

• Call light
• Side rails
• Assist with ambulating

Hematology Labs

• Labs & Diagnostics

Laboratory Testing

• Peripheral Blood Smear

White Blood Cells WBCs

• 5-10 thousand (can be lower in elderly 4,500) (high:25000:leukemia) if high

Elevated

• Infection
• Inflammation
• Tissue injury or death

Decreased

• Leukopenia