Anatomy and Functions of the Eye

Anatomy of the External Eye

• The external structures of the eye include the eyebrows, eyelids, lacrimal glands, and conjunctiva
• The lacrimal structures are located near the eye and produce tears to lubricate the eye
• The external eye structures protect the eye from injury and debris.

Eye Movement

• The extraocular muscles control eye movement
• Muscles include superior oblique, superior rectus, lateral rectus, inferior rectus, and inferior oblique.

Anatomy of the Internal Eye

• The internal eye includes the sclera, retina, choroid, vitreous body, lens, iris, ciliary body, cornea, anterior chamber, posterior chamber, and canal of Schlemm.
• The structures of the internal eye work together to focus light on the retina and transmit images to the brain.

Gerontologic Considerations

• Age-related changes affect the eye, including dry eye, changes to the eyelids and lacrimal structures, refractive changes, cataracts, and age-related macular degeneration.

Eye Assessment

• Assessment includes history, common complaints (change in vision, pain, discomfort, discharge), past and family history, and social history
• Physical assessment includes visual acuity testing, external eye examination (checking for issues with the eyelids), direct ophthalmoscopy, and diagnostic exams.
• Tests like Amsler Grid, tonometry, perimetry testing, and color vision testing may be performed with more specialized examinations.

Accommodation

• Accommodation is the ability to adjust focus (to focus on near and distant objects)
• Focusing is achieved primarily by changing the shape of the lens to alter its refractive power.

Accommodation - Age Related Changes

• Accommodation diminishes with age due to stiffened lens and loss of elasticity, making objects at a certain distance more easily seen.

Nursing Management of Visually Impaired Patients

• Goal is to preserve function for as long as possible
• Goals for management include emotional, physical, and social adaptation and providing appropriate resources.
• This involves encouraging healthy coping strategies, promoting independence in daily activities, and addressing emotional needs related to vision loss.

Nursing Management for Patients with Eye and Vision Disorders

• Strategies focus on promoting coping, spatial orientation, and mobility, and home and community based care.
• Nursing involves advocacy for social services referral and disability benefits.
• Nursing care involves communication, identifying and respecting the patient, specific instructions for directions, and appropriate assistance during tasks.

Glaucoma - Pathophysiology and Clinical Presentation

• Glaucoma is a group of ocular conditions characterized by optic nerve damage and Increased Intraocular Pressure (IOP)
• Two main types are Open-Angle and Angle-Closure Glaucoma
• Classifications; open-angle, acute angle-closure, and chronic angle-closure
• Clinical presentation includes pain, redness, blurred vision, and halos around lights.

Risk Factors for Glaucoma

• Family history, race, age, diabetes mellitus, and cardiovascular disease are all risk factors
• Prolonged use of topical or systemic corticosteroids can also be a risk factor

Progression of Glaucoma

• Initial events can include illness, emotional stress, congenital narrow angles, long-term use of corticosteroids, and use of mydriatics.
• Structural alterations in the aqueous outflow system and functional alterations (increased IOP, impaired blood flow) can lead to optic nerve damage and visual loss.
• Different types of glaucoma have different characteristics in terms of visual field loss and disease progression.

Cataract - Risk Factors and Pathophysiology

• Aging is the primary risk factor for cataract formation
• Cataracts form due to clumping or aggregation of lens proteins, leading to light scattering and a loss of lens transparency
• Cataracts are classified as nuclear, cortical, and posterior subcapsular.

Retinal Detachment - Pathophysiology and Clinical Presentation

• A retinal detachment occurs when the retina separates from the underlying tissue
• Detachment is often caused by fluid accumulation between the layers of the retina or traction.
• Clinical presentation may include flashes of light, floaters, and a gradual loss of vision

Medical Management of Retinal Detachment

• Treatment modalities may include a surgical intervention, such as scleral buckling or vitrectomy.
• Postoperative care for surgical intervention include patient education about signs and symptoms of retinal detachment complications (pain, sudden changes in vision, redness, excessive pain, swelling, and bleeding).

Macular Degeneration - Etiology, Types, and Risk Factors

• Macular degeneration is a leading cause of visual loss with wet and dry types
• It involves progressive damage to the macula, the central part of the retina responsible for sharp central vision.
• Risk factors include increasing age, smoking history, hypertension, and overweight

Orbital Trauma - Types and Management

• Orbital trauma includes head injuries, soft tissue injuries, orbital fractures, and foreign body injuries
• The type of injury determines which treatment is needed.
• Appropriate medical interventions, such as irrigation with normal saline solution and agents that paralyze the ciliary muscle (cycloplegic agents) are used for injuries to affected parts of eye.
• Nursing management includes patient instruction to report any changes to the physician or surgeon.

Conjunctivitis - Types, Clinical Presentation, and Management

• Conjunctivitis is an inflammation of the conjunctiva.
• Types include microbial (bacterial or viral), allergic, and toxic.
• Mild conjunctivitis resolves on its own; however, some may require antibiotics.
• Treatment usually involves antibiotic agents for bacterial conjunctivitis, cold compresses, eye drops, and medications as needed.