Chapter 58 Chapter 58

Assessment and Management of

Patients With Eye and Vision Disorders

External Structures of the Eye

Cross-Section of the Eye

Assessment and Evaluation of Vision

Ocular history

Visual acuity Snellen chart

Record each eye 20/20 means the patient can read the “20” line

at a distance of 20 feet

Finger count or hand motion

Diagnostic EvaluationOphthalmoscopy

Direct and indirectExamines the cornea, lens and retina

TonometryMeasures intraocular pressure

Impaired VisionRefractive errors

Can be corrected by lenses which focus light rays on the retina

Myopia: nearsightedHyperopia: farsightedAstigmatism: distortion due to irregularity

of the cornea. Due to refractive error in which light rays are spread over a diffuse area rather than sharply focused on the retina, a condition caused by differences in the curvature of the cornea and lens

GlaucomaA group of ocular conditions in which damage to

the optic nerve is related to increased intraocular pressure (IOP) caused by congestion of the aqueous humor

The leading cause of blindness in adults in the U.S.

Incidence increases with ageRisk factors

Family history of glaucomaOlder ageDiabetes mellitusCardiovascular diseaseNearsightedness (myopia)Eye traumaProlonged use of topical or systemic corticosteroids

Pathophysiology of GlaucomaIn glaucoma, aqueous

production and drainage are not in balance.

When aqueous outflow is blocked, pressure builds up in the eye.

Increased IOP causes irreversible mechanical and/or ischemic damage to the optic nerve.

Types of glaucoma:1. Open-angle

2. Angle-closure (pupillary block) glaucoma

3. Congenital glaucomas

4. glaucoma secondary to other conditions

Clinical Manifestations“Silent thief” of vision; unaware of the

condition until there is significant vision loss; peripheral vision loss, blurring, halos, difficulty focusing, difficulty adjusting eyes to low lighting

May also have aching or discomfort around eyes or headache

Diagnosis: Tonometry to assess IOP

Treatment

Goal is to prevent further optic nerve damage

Maintain IOP within a range unlikely to cause damage

Pharmacologic therapy

Surgery (nursing care)

CataractsAn opacity or cloudiness of the lensIncreased incidence with aging; by age 80 more than

half of all Americans have cataractsRisk factors

Aging (Clumping or aggregation of lens protein) Associated Ocular Conditions (Myopia, retenal

surgery)Toxic Factors (Corticosteroids, smoking)Nutritional Factors (low antioxidants, poor nutrition)Physical Factors (dehydration, trauma, ultraviolet

ray)Systemic Diseases and Syndromes (DM, MS Renal)

Cataract

Clinical ManifestationsPainless, blurry vision Sensitivity to glareReduced visual acuityOther effects include astigmatism,

diplopia (double vision), and color (color value shift to yellow-brown)

Diagnostic findings include decreased visual acuity and opacity of the lens by ophthalmoscope, or inspection

Surgical Management

If reduced vision does not interfere with normal activities, surgery is not needed.

Removal of the lens and replacing it with an artificial lens

Retinal DetachmentSeparation of the sensory retina and the

RPE (retinal pigment epithelium)Manifestations: sensation of a shade or

curtain coming across the vision of one eye, bright flashing lights, sudden onset of floaters

Diagnostic findings: assess visual acuity, assessment of retina by indirect ophthalmoscope and fluorescein angiography. Tomography and ultrasound may also be used

Retinal Detachment

Surgical TreatmentScleral Buckle

Trauma

Prevention of injury

Patient and public educationEmergency treatment

Flush chemical injuriesDo not remove foreign objectsProtect using metal shield or paper

cup

Protective Eye Patches