Module 2.1: Sensory System & Neurological System - Part C: Problems of the visual system

Module 2.1: Sensory System & Neurological System - Part C: Problems of the Visual System

Eye Anatomy

• Layers of the Eye:

  • Fibrous layer

  • Vascular layer

  • Inner layer

• Key Structures:

  • Lacrimal caruncle

  • Optic disc

  • Central artery and vein

  • Optic nerve

  • Anterior chamber (contains aqueous humor)

  • Cornea (transparent)

  • Visual (optic) axis

  • Lens

  • Pupil

  • Iris

  • Fovea centralis

  • Macula

  • Superior canaliculus

  • Superior lacrimal punctum

  • Inferior canaliculus

  • Lower (inferior) lid

  • Ciliary body

  • Suspensory ligament

  • Retina

  • Choroid

  • Sclera

  • Posterior chamber (contains vitreous humor)

  • Lacrimal gland

  • Lacrimal sac

  • Nasolacrimal duct

  • Opening into inferior meatus of nose

Impact of Vision Problems

• Poor vision or blindness can significantly impact activities of daily living (ADL) and independence.

• Every structure of the eye is subject to change, which can range from minor, repairable issues to severe, vision-compromising conditions.

Assessment of Visual Problems

Subjective Assessment

• Health History:

  • Systemic diseases that may lead to eye manifestations.

  • When was the last eye test?

• Medications:

  • Many drugs affect the eye:

    • Pseudoephedrine (epi): Dilated pupils.

    • Antihistamines, decongestants: Dry eyes.

    • Long-term corticosteroids: May lead to glaucoma or cataracts with long-term use.

    • Beta-blockers (and beta-blockers for glaucoma): Check if the patient is on other beta-blockers; monitor blood pressure.

    • Hydroxychloroquine for rheumatoid arthritis (RA): May result in retinal toxicity.

• Surgical History:

  • Laser or any other invasive surgeries.

• Functional Health Patterns:

  • Health perception-health management pattern: Consider age, gender, ethnicity.

  • Family history

  • Genetic risk: Glaucoma, macular degeneration.

  • Cognitive-perceptual pattern: Hearing problems may be further compromised by vision issues.

  • Self-perception-self-concept: Vision loss or impairment can be devastating.

  • Role-relationship: Impact on daily family roles.

Objective Assessment

• Physical assessment:

  • Inspection of the eye structure using an ophthalmoscope to visualize blood vessels and the optic nerve.

• Focused Assessment:

  • Initial observation/inspection: Note how they are dressed; if they cover their eyes from the light; how they reach to shake your hand (depth perception). These are clues to underlying visual changes.

    • Symmetry and normal placement on the face.

    • Exophthalmos: Bulging of the eyes.

    • Brows, lashes: Note any loss of hair.

    • Ptosis: Drooping.

• Functional Status:

  • Visual acuity (Snellen chart: 20 feet away): Understanding what 20/40 vision means.

  • Pupil function.

  • Accommodation.

  • Conjunctiva and sclera: Color (clear) or smoothness, foreign bodies.

  • Cornea: Should be clear, transparent.

  • Iris: Not bulging, similar color.

  • Optical nerve: Creamy yellow; examine the size and shape. Look for any tears, detachments, or lesions (diabetes or hypertension may present small hemorrhages).

  • Eye movement: EOM, nystagmus.

  • Palpate over lacrimal glands, puncta, and nasolacrimal duct for tenderness.

• Diagnostic Tests:

  • Ultrasound, fluorescein angiography, perimetry (visual field) testing.

Older Adult/Gerontological Assessment

• Xanthelasma: Yellow growth appearing on or by the corner of the eyelids next to the nose, may indicate diabetes.

• Arcus senilis: Affects the cornea.

Structural and Functional Changes in Older Adults

• Structural Changes:

  • Ptosis: Drooping upper eyelid.

  • Ectropion: Eyelid turns outward.

  • Arcus senilis.

• Functional Changes:

  • Presbyopia

  • Far point of vision decreases.

• General color perception changes.

Diagnostic Testing

• Ophthalmoscopy

• Other Diagnostic Assessments:

  • Imaging (CT, MRI, US of retina and optic nerve)

  • Tonometry

  • Fluorescein angiography: Provides information on blood flow through retinal vessels.

Administering Eye Medications

Nursing Care for Patients with Visual Problems

• Refractive Errors:

  • Refraction is the eye’s ability to bend light rays so that they fall on the retina.

  • Myopia: Nearsightedness.

  • Hyperopia: Farsightedness.

  • Presbyopia: The loss of accommodation associated with age; the lens becomes firmer and less elastic.

  • Astigmatism: Uneven or irregular curvature of the cornea.

  • Most corrected by lenses, refractive surgery, or artificial lens implant.

• Nursing Considerations for Older Adults:

  • Visual Impairment

  • Legal blindness

Extraocular Disorders

• Inflammation and Infection affecting the eye, conjunctiva, and cornea.

  • Sty

  • Conjunctivitis (bacterial or viral): Hand washing to prevent spreading.

  • Keratitis: Inflammation of the cornea.

  • Dry eye disorder: May need artificial tears or ointments.

• Nursing Management:

  • Access for ocular changes.

  • Note if a patient needs two different eye drops; stagger the eye drops for better absorption.

  • If pain, darken the room, consider cold compresses, and administer analgesics.

Corneal Disorders

• Corneal Scars:

  • Abrasion: Scrape injury.

  • Causes: Infection (keratitis) - bacterial, viral, fungal.

  • Ulceration.

• Corneal Transplant

Cataracts

• Age-related (senile cataracts).

• Pathophysiology:

  • An opacity within the lens.

  • May occur in one or both eyes.

  • The eye lens is no longer clear; it is cloudy, resulting in cloudy, distorted vision.

  • Light is unable to reach the retina.

• Clinical Manifestations:

  • Decrease in vision, gradual.

  • Abnormal color perception.

  • Increased glare, especially at night (trouble driving).

• Diagnosis

  • Decreased visual acuity.

  • Opacity is directly observed by ophthalmoscopic exam.

• Treatment

  • Nonsurgical:

    • Change in glasses prescription.

    • Magnifiers or strong readers may be needed.

    • Increased lighting.

    • Lifestyle adjustment.

  • Surgical:

    • Cataract removal.

      • Pre-op: Outpatient basis.

      • Post-op: teaching

      • Phacoemulsification: Small incision is made in the surface of the eye in or near the cornea.

        • Preop: Cyclopegic medication (anticholinergic that produces paralysis of accommodation and pupillary dilatation)

        • Mydriatic medication (alpha adrenergic agonist that produces pupillary dilatation)

        • Postop: home after sedative agents have worn off. Teach safety.

        • Home care recommendations: avoid activities that increase the IOP (bending, stooping, coughing, and lifting).

        • Pay attention to head positioning.

        • Patient and caregiver teaching.

Retinal Disorders

• Retinopathy: Microvascular damage to the retina.

• Retinal Detachment: Separation of the sensory retina and the underlying pigment epithelium, with fluid accumulation between the 2 layers.

• Macular Degeneration: Age-related macular degeneration (AMD) is the most common cause of irreversible central vision loss in people over age 60 in the US.

  • Deterioration of the macula at the back of the eye.

  • Dry (more common): Macular cells begin to atrophy, leading to slowly progressive and painless vision loss.

  • Wet: Development of abnormal blood vessels in or near the macula.

  • Leaking of blood vessels; blurred or darkened vision; vision distortion.

  • Wear sunglasses, make home modifications (loss of central vision), follow-up care with eye exam.

  • Taking supplements (vitamin C, vitamin E, zinc) may help slow progression.

  • Teach patients to eat dark green leafy vegetables.

Glaucoma

• A group of disorders characterized by increased intracranial pressure and its consequences, atrophy of the optic nerve, and peripheral field loss.

• Optical nerve damage; early detection is key.

• Types:

  • Primary open-angle glaucoma (POAG) – most common (silent).

  • Acute angle-closure glaucoma (AACG or acute glaucoma): Immediate emergency treatment.

  • Normal eye: Aqueous humor flows freely through the trabecular meshwork and the canal of Schlemm.

  • Angle-closure glaucoma: Closure of the anterior angle due to contact between the iris and the trabecular meshwork prevents aqueous humor from exiting, which leads to increased intraocular pressure.

  • Open-angle glaucoma: The anterior angle remains open, but the canal of Schlemm is obstructed by tissue abnormalities (like a clogged sink).

• Clinical Manifestations:

  • Vision loss develops slowly.

  • Eventual "tunnel vision"; all peripheral vision is absent.

• Diagnosis:

  • Increased intraocular pressures (normal 10-21 mm Hg).

  • Measurement of peripheral and central vision.

• Treatment:

  • The main focus is to keep the IOP low enough to prevent patients from developing optic nerve damage.

    • Chronic open-angle glaucoma:

      • Medications do not improve vision but prevent further deterioration:

        • Prostaglandin analogs, adrenergic agonists, beta-adrenergic blockers (watch taking other beta-blockers and contraindications for beta blockers), carbonic anhydrase inhibitors.

    • Surgery

      • Laser to lower IOP if necessary.

• Nursing Considerations:

  • Education: Ensure patients adhere to the treatment plan.

  • Include caregiver.

  • Sensory deficit

  • Pain

  • Impaired role performance

• Drug classes and effects on pupils

• Glaucoma medication

  • Drugs used to decrease IOP:

    • Adrenergic agonists

    • Beta-adrenergic blockers

    • Carbonic Anhydrase Inhibitors

    • Prostaglandin Agonist

Home Safety for Clients with Impaired Vision

• Promote safe, independent living for a patient with impaired vision?

  • Safety

  • Medication administration

  • Communication

  • Preparing food

  • ADLs

  • Leisure

Questions Review

1. What nursing action is most important for the patient with age-related dry macular degeneration?

   • B. emphasize the use of vision enhancement techniques to improve what vision is present.

   • 2. A 60-year-old patient is being prepared for outpatient cataract surgery, when obtaining admission data from the patient what would the nurse expect to find in the patient history

2. C. a gradual loss of vision with abnormal color perception and glare