Visual

Sensory System: The Optic System

Extraocular Structures

  • Components:
      - Eyelids: Protect the eye and help in tear spreading.
      - Conjunctiva: Mucous membrane covering the front of the eye and lining the eyelids.
      - Eyelashes: Protect from debris and foreign particles.
      - Tears: Important for lubrication and protection of the eye.

  • Lacrimal System:
      - Lacrimal gland
      - Accessory lacrimal glands
      - Lacrimal canaliculi
      - Lacrimal sac
      - Puncta
      - Lacrimal duct

Intraocular Structures

  • Components:
      - Sclera: The white outer layer of the eyeball.
      - Iris: The colored part of the eye; regulates the diameter of the pupil.
      - Pupil: Opening in the center of the iris; helps control the amount of light entering the eye.
      - Aqueous Humor: The clear fluid in the front part of the eye.
      - Vitreous Humor: The gel-like substance filling the eye.
      - Optic Disc: The point where the optic nerve enters the eye.
      - Retina: Light-sensitive layer at the back of the eye.
      - Lens: Focuses light onto the retina.
      - Macula: Area of the retina responsible for central vision.

Vision Health Promotion

  • Recommendations:
      - Regular eye exams with an ophthalmologist (recommended ages: 2-4 years, 40-65 years, and every 1-2 years for >65 years).
      - Eye protection: Use of sunglasses to prevent UV damage.
      - Knowledge of family eye history.
      - Nutrition: Promoting healthy weight, resting eyes appropriately.
      - Following the 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds.

Age-Related Changes

  • Common conditions include:
      - Cataracts
      - Drooping eyelids
      - Dry eyes
      - Vitreous floaters
      - Vascular changes
      - Glaucoma
      - Macular degeneration
      - Presbyopia

Assessment and Evaluation of Vision

  • Components of Assessment:
      - Ocular history: Collect patient history regarding vision.
      - Visual acuity assessments using:
        - Snellen chart for distance vision.
        - Rosenbaum pocket screener for near vision.
        - Finger count or hand motion for basic evaluation.

Examination of the External Structures

  • Assess for:
      - Evidence of irritation, inflammatory processes, discharge.
      - Eyelids and sclera conditions.
      - Pupils and pupillary response (use darkened room).
      - Gaze and position of eyes.
      - Extraocular movements:
        - Ptosis: Drooping eyelid.
        - Nystagmus: Oscillating movement of the eyeball.

Diagnostic Tests

  • Techniques used include:
      - Ophthalmoscopy (both direct and indirect types).
      - Slit-lamp examination.
      - Color vision testing.
      - Amsler grid: Assesses visual field problems.
      - Ultrasonography.
      - Optical coherence tomography.
      - Fundus photography.
      - Tonometry: Measures intraocular pressure.
      - Laser scanning.
      - Angiography.
      - Perimetry testing: Assesses peripheral vision.

Impaired Vision

  • Refractive Errors:
      - Eyeball shape affects visual acuity and can be corrected by lenses.
      - Types of refractive errors:
        - Emmetropia: Normal vision.
        - Myopia: Nearsightedness.
        - Hyperopia: Farsightedness.
        - Astigmatism: Caused by irregularity of the cornea.

Refractive Errors Symptoms and Treatments

  • Symptoms: Blurred vision, headaches.

  • Treatment Options:
      - Glasses, contact lenses, or surgical options.
      - Types of surgeries:
        - Incisional radial keratotomy: Reshapes cornea through incisions.
        - LASIK: Corneal flap lifted, laser reshapes cornea.
        - Photorefractive keratectomy: Epithelium removed, laser reshapes eye.
      - Complications include: Abrasions, infections, worsening vision.

Low Vision and Blindness

  • Definitions:
      - Low vision: Visual impairment requiring the use of devices for tasks.
      - Blindness: Best Corrected Visual Acuity (BCVA) is 20/400 to no light perception.
      - Legal blindness defined as BCVA not exceeding 20/200 in the better eye or field of vision less than 20 degrees.
      - Often accompanied by functional impairment.

Assessment of Low Vision

  • Key Components:
      - History taking.
      - Examination metrics:
        - Distance and near visual acuity.
        - Visual field assessments.
        - Contrast sensitivity, glare testing, color perception, and refraction.
      - Special charts for low vision assessments.
      - Consider coping and adaptation strategies for emotional, physical, and social aspects.

Eye Trauma

  • Prevention: Education for patient and public.

  • Emergency Treatment:
      - Flush chemical injuries; do not remove foreign objects.
      - Protect with metal shield or paper cup.

  • Potential Consequence: Sympathetic ophthalmia can cause blindness in uninjured eye with certain injuries.

  • Symptoms: Gritty sensation, tearing, blurry vision, diplopia.

Safety Measures & Education

  • Patient education is crucial for individuals with eye disorders.

  • Strategies for:
      - Preventing eye injuries.
      - Supporting safety for low vision patients in different settings.
      - Educating after surgery or trauma about potential complications and how to manage them (e.g., using eye patches).

Infectious & Inflammatory Disorders

  • Common Disorders:
      - Dry eyes: Often a chronic problem affecting stability of tears.
      - Conjunctivitis: Also known as “pink eye”, classified by cause, such as:
        - Bacterial, viral, fungal, parasitic, allergic, toxic.
        - Viral conjunctivitis is contagious.
      - Uveitis: Inflammation of the uveal tract.
      - Orbital cellulitis: Infection around the eye.

Conjunctivitis Symptoms and Treatment

  • Symptoms: Redness, tearing, purulent exudate, lesions with herpes, pain, photophobia.

  • Treatment:
      - Eye drops, warm soaks, saline flushes, and good hand hygiene.

Uveitis

  • Definition: Inflammation of the uveal tract.

  • Symptoms: Blurred vision, photophobia.

  • Treatment: Steroids administered via drops, local injections, oral or IV options.

Ocular Consequences of Systemic Disease

  • Conditions:
      - Diabetic retinopathy: Major cause of blindness in adults over 40.
      - Ophthalmic complications associated with AIDS.
      - Eye changes linked to hypertension.

Blepharitis

  • Definition: Inflammation of the lid margins.

  • Treatment: Topical antibiotic ointment, BID eyelid cleaning, frequent facial washing.

Hordeolum (Sty)

  • Definition: Infection of eyelid glands.

  • Symptoms: Swelling, pain, red pustule on the eyelid.

  • Treatment: Warm soaks, topical antibiotics, possible incision and drainage (I&D).

Chalazion

  • Definition: Cyst on the inner eyelid gland, often painless.

  • Treatment: Warm soaks, massage, possible I&D.

Macular Degeneration

  • Importance: Leading cause of irreversible blindness and visual impairment worldwide.

  • Types:
      - Dry (nonexudative): Most common (85-90%); slow breakdown of retina layers with drusen appearance.
      - Wet: Abrupt onset with proliferation of abnormal blood vessels under the retina.

Vision Loss Associated with Macular Degeneration

  • Assessing the impact on daily living and potential support needs.

Macular Degeneration: Nursing Management

  • Goals:
      - Patient education.
      - Provide supportive care.
      - Promote safety: improve lighting, recommend magnification devices, and referrals to vision centers.

Glaucoma

  • Definition: A group of diseases causing damage to the optic nerve associated with increased intraocular pressure (IOP).

  • Incidence: Increases with age.

  • Risk Factors: Age > 40, family history, eye disease/trauma, ethnicity.

  • Physiology: Imbalance in aqueous humor production and drainage can cause pressure build-up.

Glaucoma Types

  • Includes:
      - Wide angle
      - Narrow angle
      - Congenital
      - Secondary glaucoma

  • Clinical Manifestations: Often referred to as the “Silent Thief”; many patients unaware until significant vision loss occurs, may experience peripheral vision loss, blurring, halos, and discomfort around the eyes.

Glaucoma Diagnostic Findings

  • Methods:
      - Tonometry for IOP.
      - Ophthalmoscopy to inspect optic nerve disc.
      - Central visual field testing.

  • Treatment Goals:
      - Prevent further optic nerve damage.
      - Maintain a safe IOP level.

Glaucoma Treatment Options

  • Pharmacologic Therapy: Includes:
      - Miotics
      - Beta-blockers
      - Alpha2-agonists
      - Carbonic anhydrase inhibitors
      - Prostaglandins

  • Surgical Procedures: May involve laser treatment.

Nursing Management of Glaucoma

  • Educating Patients: Assess knowledge and compliance; educate about the use and effects of medications.

  • Support: Assist with coping strategies for potential vision loss.

Cataracts

  • Definition: Clouding of the lens.

  • Incidence: By age 80, more than half of Americans may have cataracts.

  • Risks: Age is a significant risk factor, along with types of cataracts (traumatic, congenital, senile).

Clinical Manifestations of Cataracts

  • Symptoms: Painless, blurry vision, diminished surroundings, glare sensitivity, reduced visual acuity.

  • Other Effects: Myopic shift, astigmatism, diplopia, color perception changes.

  • Diagnostic Findings: Decreased visual acuity and lens opacity as seen through an ophthalmoscope or slit lamp.

Surgical Management of Cataracts

  • Indications for Surgery: Only if reduced vision affects daily activities.

  • Procedure Details: Performed outpatient under local anesthesia, taking less than an hour, with patients being discharged shortly thereafter.

  • Surgical Techniques:
      - Phacoemulsification: Uses ultrasonic device to remove the lens through a smaller incision.
      - Lens replacement: Involves inserting an intraocular lens (IOL).

Nursing Management of Cataracts

  • Preoperative Care:
      - Standard care for outpatient procedures; administer dilation drops as needed.

  • Postoperative Care:
      - Provide thorough education on medications, symptoms to monitor, and when to seek help regarding vision changes.

Retinal Detachment

  • Definition: Separation of sensory retina from the retinal pigment epithelium (RPE).

  • Manifestations: Patients may report sensations such as a curtain coming across vision, bright flashing lights, or sudden floaters.

  • Diagnostic Findings: Assess visual acuity and retina through examinations using indirect ophthalmoscope, slit lamp, and advanced imaging techniques.

Retinal Detachment Surgical Treatment

  • Procedures include:
      - Scleral buckle: Compresses the sclera to reattach the retina.
      - Vitrectomy: An intraocular procedure possibly involving the injection of a gas bubble or silicone oil.

  • Patient Education: Essential post-op instruction regarding signs of complications and maintaining comfort (e.g., lying prone).

Enucleation

  • Definition: Surgical removal of an eye from the eye socket under general anesthesia.

  • Indications:
      - Eye cancer treatment (e.g., malignant melanoma).
      - Relief of pain in end-stage glaucoma.
      - Trauma management for aesthetic restoration after injury.
      - Prevention of infection in untreatable cases.

Ocular Medication Administration

  • Challenges: Limited absorption due to anatomical barriers such as the conjunctival sac and corneal membranes.

  • Options: Intraocular or systemic administration might be necessary for certain conditions. Topical medications are commonly used due to their non-invasive nature and lower side effect profile.

Ophthalmic Medications

  • Types and Uses:
      - Topical anesthetics, Mydriatics (for dilation), and Cycloplegics (for paralysis); precautions are crucial for patients with narrow angles or on certain antidepressants.
      - Anti-infective medications including antibiotics, antifungals, and antivirals.
      - Medications for glaucoma aimed at increasing aqueous outflow or decreasing production; many have systemic effects and potential side effects including risk of infection and vision alterations.
      - Long-term corticosteroids may lead to complications such as glaucoma and cataracts; alternatives include NSAIDs for reducing inflammation without these risks.