Chapter 22 Visual and Auditory Problems Flashcards
Correctable Refractive Errors
This defect prevents light rays from converging into a single focus on the retina
Result of irregularities of the corneal curvature
Focusing power of the lens
Length of the eye
Major symptom is blurred vision
Additional symptoms: ocular discomfort, eyestrain, or headaches
Myopia
(nearsightedness)
Inability to accommodate for objects at a distance
Causes light rays to be focused in front of the retina
May occur because of excessive light refraction by the cornea or lens or because of an abnormally long eye
Hyperopia
Hyperopia (farsightedness)
Inability to accommodate for near objects
Causes light rays to be focused behind the retina
May occur because the cornea or lens does not have adequate focusing power or when the eyeball is too short
Presbyopia
(loss of accommodation due to age)
As the eye ages, the lens becomes larger, firmer, & less elastic
Inability to focus on near objects
Astigmatism
(an irregular corneal curvature)
Causes the incoming light rays to be bent unequally
Light rays do not come to a single point of focus on the retina
Aphakia is the absence of the lens (absent congenitally or removed during cataract surgery)
Replaced with an intraocular lens (IOL) implant
Corrective Glasses
Myopia, hyperopia, presbyopia (reading glasses) & astigmatism
Combined corrective glasses (presbyopic correction is in the lower portion of the spectacle lens); “bifocals”
Distance focusing in the top two thirds & near focus in the bottom one third of the lens
Contact Lens
Pattern of wear (daily versus extended)
Microbial keratitis – poor hand or lens case hygiene
Patient education key for the prevention of sight-threatening complications
Laser
(laser-assisted in situ keratomileusis – LASIK)
Creates a flap in the cornea, flap is folded back on the middle section, or stroma of the cornea
Laser pulses vaporize a part of the stroma
Flap is then repositioned
Implant
Refractive intraocular lens implantation is an option for patients with a high degree of myopia or hyperopia
Removal of the patient’s natural lens
Risk of complications is higher
Phakic intraocular lens implantation
Implanted into the eye without removing the eye’s natural lens, placed in front of the eye’s lens
Preserves the eye’s ability to focus for reading vision
Uncorrectable Visual Impairment
In the U.S., 6.5 million people over the age 65 have severe visual impairment
inability to read newsprint even with glasses
9% have no useful vision
91% are partially sighted
Total blindness – no light perception & no usable vision
Functional blindness – some light perception & no usable vision
Legal blindness – central visual acuity of 20/200 or less in the better eye with correction, or a peripheral visual field of 20 degrees or less
1.3 million people in the U.S. are legally blind
Assessment
How the patient’s visual impairment affects functioning
Personal feelings & meaning
Support System
Planning
Successful Adjustments
Coping Strategies
Goals
Implementation
Health Promotion Acute Intervention Patient & Family Respect & Communication Sight-guide technique Ambulatory & Home Care Rehabilitation services American Foundation for the Blind (www.afb.org) ADLs Optical Devices for Visual Enhancement Nonoptical Methods for Visual Enhancement
Evaluation
Expected outcomes
No further loss of vision
Use adaptive coping strategies
Maintain self-esteem or social interactions (no decrease)
Function safely within environment (personal & outside the home)
Gerontologic Considerations
Older adults is at increased risk for vision loss caused by eye disease
Other deficits (cognitive impairment, limited mobility) may further affect the older adult’s function in usual ways
Higher risk for falls
Diminished self- esteem and independence
Decreased manual dexterity may cause difficulty with eyedrops instillation
Eye Trauma
In the U.S. approximately 2.5 million eye injuries occur each year
More than 10% will lose useful vision in the affected eye
Most common ocular injuries occur in the home
Followed by sport and work-related injuries
Eye trauma often is a preventable injury
Protective eyewear
Role of Nursing – patient and community education
Herdeolum
(sty)- infection in sebaceous glands in lid margin
Most common - Staph aureus
May evolve into inflammation of gland → Chalazion
Apply warm, moist compresses at least four times a day
If no improvement refer to ophthalmologist for lancing or removal
Chalazion
chronic inflammatory granuloma of the meibomian (sebaceous) glands in the lid
Blepharitis
Bilateral infection of the lid margins
Lids are red rimmed with scales or crusts on the lid margins and lashes
May experience burning, irritation and photophobia
Ophthalmic ointment
Emphasize thorough cleaning practices of skin & scalp – baby shampoo
Bacterial Conjunctivitis
most common
Commonly occurs in children due to poor hygienic habits
Irritation, tearing, redness, drainage
Antibiotics and hand washing
Viral Conjunctivitis
Tearing, foreign body sensation, redness
Adenovirus conjunctivitis: contaminated swimming pools, direct contact
Good hygiene and palliative care