Transcript Nursing Management

Visual Impairment
(Glaucoma & Cataract)
Dr. Belal M. Hijji, RN, PhD
May 18 & 21, 2011
Learning Outcomes
At the end of this lecture, students will be able to:
• Recognise the causes and effects of visual impairment
on an individual.
• Define glaucoma and identify its clinical manifestations.
• Identify diagnostic tests for assessment of glaucoma and
cataract.
• Discuss the medical and nursing management of
patients with glaucoma and cataract.
2
Introduction
• Impaired vision affects an individual’s independence in
self-care, work and lifestyle choices, sense of selfesteem, safety, ability to interact with society and the
environment, and overall quality of life. Many of the
leading causes of visual impairment and blindness are
cataracts, glaucoma, macular degeneration, and diabetic
retinopathy. Younger people are also at risk for eye
disorders, particularly traumatic injuries.
3
Glaucoma
• Glaucoma is a group of ocular conditions characterized
by optic nerve damage which is related to high IOP
caused by congestion of aqueous humor in the eye.
• Glaucoma is one of the leading causes of irreversible
blindness in the world. So far, there is no cure for
glaucoma.
Clinical Manifestations
• Most patients are unaware that they have the disease
until they have experienced visual changes and vision
loss.
• Patients experiences blurred vision or “halos” around
lights, difficulty focusing, difficulty adjusting eyes in low
lighting, loss of peripheral vision, aching or discomfort
around the eyes, and headache.
4
Assessment and Diagnostic Findings
• The patient’s ocular and medical history must be detailed
to investigate the history of predisposing factors.
• The major types of examinations are: tonometry to
measure the IOP, ophthalmoscopy to inspect the optic
nerve, gonioscopy and perimetry to assess the visual
fields.
• Changes in the optic nerve significant for diagnosis are
pallor and cupping of the optic nerve disc. Cupping is
characterized by exaggerated bending of the blood
vessels as they cross the optic disc, resulting in an
enlarged optic cup that appears more basinlike compared
with a normal cup.
• As the optic nerve damage increases, visual perception in
the area is lost.
5
6
Gonioscopy describes the use of a gonioscope in conjunction with a
slit lamp or operating microscope to gain a view of the iridocorneal
angle, or the anatomical angle formed between the eye's cornea and
iris.
7
8
Medical Management
• Treatment aims at preventing optic nerve damage
through medical therapy, laser or non-laser surgery, or a
combination.
• Lifelong therapy is indicated as glaucoma is not curable.
Optic nerve damage is irreversible. However, further
damage can be controlled by maintaining an IOP within
an acceptable range (10-21 mmHg).
• The initial target for IOP reduction is typically set at 30%
lower than the current pressure. If there is evidence of
progressive damage, the target IOP is again lowered
until the optic nerve shows stability.
9
Pharmacologic Therapy
• The IOP lowering systemic and topical medications.
• The patient is usually started on the lowest dose of
topical medication (beta-blockers) and then advanced to
increased concentrations until the desired IOP level is
reached and maintained.
• One eye is treated first, with the other eye used as a
control; once efficacy has been established, treatment of
the fellow eye is started.
• If the IOP is elevated in both eyes, both are treated.
• When results are not satisfactory, a new medication is
substituted.
• The main markers of the efficacy of the medication in
glaucoma control are lowering of the IOP to the target
pressure, appearance of the optic nerve head, and the
visual field.
10
• Several types of ocular medications are used to treat
glaucoma by decreasing aqueous humor production and/
or increasing aqueous fluid outflow between the iris and
lens. These include alpha adrenergic agonists
(apraclonidine), beta-blockers (timolol), adrenergic
agonists (epinephrine), miotics (pilocarpine), carbonic
anhydrase inhibitors (acetazolamide), and
prostaglandins (latanoprost). All these medications
(except pilocarpine) reduce aqueous humor production.
Pilocarpine increases aqueous fluid outflow causing
miosis (constriction of the pupil).
11
Surgical Management
• In laser trabeculoplasty for glaucoma, laser burns
promote outflow of aqueous humor and decreasing IOP.
• The procedure is indicated when IOP is inadequately
controlled by medications.
• A serious complication of this procedure is a transient
rise in IOP (usually 2 hours after surgery) that may
become persistent. IOP assessment in the immediate
postoperative period is essential.
• In laser iridotomy for pupillary block glaucoma, an
opening is made in the iris to eliminate the pupillary
block.
• Potential complications are burns to the cornea, lens, or
retina; transient elevated IOP; closure of the iridotomy;
uveitis (iritis); and blurring. Pilocarpine is usually
prescribed to prevent closure of the iridotomy.
12
Nursing Management
• Teaching patients about glaucoma care
– The lifelong therapeutic regimen mandates patient
education.
– Nurses should stress the importance of strict adherence to
the medication regimen.
– Nurses encountering patients with glaucoma as a
secondary diagnosis should assess their level of
knowledge and compliance with the therapeutic regimen.
13
• Continuing glaucoma care at home
– For patients with severe glaucoma, referral to services that
assist the patient in performing customary activities may
be needed.
– The loss of peripheral vision impairs mobility the most.
These patients need to be referred to low vision and
rehabilitation services.
– Reassurance and emotional support are important aspects
of care.
– The family must be integrated into the plan of care, and
family members should be encouraged to screen for
glaucoma.
14
Cataracts
• A cataract is a lens opacity or cloudiness that can affect
one or both eyes.
• According to the World Health Organization, cataract is
the leading cause of blindness in the world.
15
.
16
Pathophysiology
• Cataracts can develop at any age for a variety of causes
including aging, retinal surgery, infections, corticosteroids,
smoking, poor nutrition, obesity, dehydration, trauma, and
DM.
• The nuclear, cortical, and posterior subcapsular cataracts
are the most common types and are defined by their
location in the lens.
• A nuclear cataract is associated with myopia (defective
vision of distant objects), which worsens when the cataract
progresses. Dense cataract severely blurs [‫]يغشى البصر‬
vision.
• A cortical cataract involves the anterior, posterior, or the
periphery of the cortex of the lens. Vision is worse in very
bright light.
• Posterior subcapsular cataracts occur in front of the
posterior capsule. In some cases, it is associated with
prolonged corticosteroid use, inflammation, or trauma.
Near vision is diminished, and the eye is increasingly
17
sensitive to glare [‫ ]ساطع‬from bright light.
Clinical Manifestations
• Painless, blurry vision is characteristic of cataracts.
• Light scattering is common, and the individual
experiences reduced contrast sensitivity, sensitivity to
glare, and reduced visual acuity, dimmer surroundings
(as if glasses need cleaning), diplopia, and brunescens
(color values shift to yellow-brown).
18
Contrast is the difference in visual properties that makes an object
distinguishable from other objects and the background. In visual perception
of the real world, contrast is determined by the difference in the colour and
brightness of the object and other objects within the same field of view.
19
Assessment and Diagnostic Findings
• Decreased visual acuity is directly proportionate to
cataract density.
• The Snellen visual acuity test, ophthalmoscopy, and
slitlamp biomicroscopic examination are used to
establish the degree of cataract formation.
• The degree of lens opacity does not always correlate
with the patient’s functional status.
• Some patients can perform normal activities despite
clinically significant cataracts. Others with less lens
opacification have a disproportionate decrease in visual
acuity; hence, visual acuity is an imperfect measure of
visual impairment.
20
Medical Management
• No nonsurgical treatment cures cataracts.
• In the early stages of cataract development, glasses,
contact lenses, strong bifocals [‫]النظارة ثنائية البؤرة‬, or
magnifying lenses may improve vision.
• Reducing glare with proper light and appropriate lighting
can facilitate reading. Mydriatics (atropine) can be used
as short-term treatment to dilate the pupil and allow
more light to reach the retina.
• Intracapsular cataract extraction. The entire lens (ie,
nucleus, cortex, and capsule) is removed, and fine
sutures close the incision. ICCE is infrequently used; it is
indicated when there is a need to remove the entire lens,
such as with a subluxated cataract (ie, partially or
completely dislocated lens).
21
• Extracapsular surgery. Extracapsular cataract extraction
(ECCE) achieves the intactness of smaller incisional
wounds (less trauma to the eye) and maintenance of the
posterior capsule of the lens, reducing postoperative
complications, particularly retinal. In ECCE, a portion of
the anterior capsule is removed, allowing extraction of
the lens nucleus and cortex.
• Lens replacement. After removal of the crystalline lens
which focuses light on the retina, it must be replaced for
the patient to see clearly.
22
Nursing Management
• Providing preoperative care
– To reduce the risk for retrobulbar hemorrhage,
anticoagulation therapy is withheld, if medically
appropriate. Aspirin should be withheld for 5 to 7
days, nonsteroidal anti-inflammatory medications
(NSAIDs) for 3 to 5 days, and warfarin (Coumadin)
until the prothrombin time of 1.5 is almost reached.
– Dilating drops are administered every 10 minutes for
four doses at least 1 hour before surgery. Additional
dilating drops may be administered in the operating
room (immediately before surgery) if the affected eye
is not fully dilated. Prophylactic antibiotic,
corticosteroid, and NSAID drops may be used.
23
• Providing postoperative care
– The nurse provides the patient with verbal and written
instruction regarding how to protect the eye,
administer medications, recognize signs of
complications, and obtain emergency care.
– The nurse instructs the patient regarding home care
(Chart 58-6, page 1764)
– The nurse also explains that there is minimal
discomfort after surgery and instructs the patient to
take a mild analgesic agent PRN. Antibiotic, antiinflammatory, and corticosteroid eye drops or
ointments are prescribed postoperatively.
24