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Label
Cataract

DefinitionEtiologyEpidemiologyPathophysiologyClinical Manifestation
WorkupRN ManagementMedsDiagnosis and GoalsInterventionAlertsRefs
Definition:

Opacity or cloudiness of the lens of an eye, causing partial or total impairment of vision.

There are 3 most common types of senile (age related) cataracts; defined by their location within the lens:

  • Nuclear: Progression of a yellow to dark brown hue of the lens with increase in density; cause of some nearsightedness as cataract progresses
  • Cortical: Located in anterior, posterior or equatorial cortex; cause glare associated with bright lights
  • Posterior subscapular: Lies in front of the posterior capsule. Effect on vision can be significant, and often worse with bright lights
  • Mixed cataract: More than one type can occur in same eye

 

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Etiology:

Age-Related - most common cause

Systemic diseases

  • Diabetes
  • Hypertriglyceridemia
  • Renal disorders
  • Other metabolic disorders (hypocalcemia, Wilson disease, myotonic dystrophy etc.)
  • Atopic dermatitis
  • Down syndrome and other chromosomal abnormalities

Ocular disease

  • Ocular tumours
  • Pathologic myopia
  • Uveitis/iritis
  • Retinal detachment
  • Ocular surgery
  • Acute angle closure glaucoma

Environmental factors

  • Ultraviolet light
  • Radiation
  • Smoking
  • Trauma

Medications

  • Chronic oral corticosteroid use and possibly prolonged administration of high doses of inhaled corticosteroids
  • Amiodarone
  • Allopurinol
  • Phenothiazines

 

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Epidemiology:
  • From an estimated >30 million blind people worldwide, ~50% is due to cataract
  • Senile catracts represent ~90% of this condition

In Canada

  • More than 2.5 million individuals have cataracts, with an anticipated rise to 5 million in 25 years
  • By 2031, almost one-quarter of Canadians over the age of 40 will have cataracts
  • Prevalence is directly proportional to age
  • Percentage according to the age is estimated to be:
    • Approx. 2.5% = 40-49 years
    • Approx. 25% = 65-69 years
    • Approx. 70% = 80 years or more

 

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Pathophysiology:
  • Lens of the eye is composed of specialized stratified epithelial cells, with high cytoplasmic protein content arranged in a highly complex manner, these proteins provide the transparency to the lens
  • The lens is incapable of shedding nonviable cells making it susceptible to degenerative effects of aging
  • New cortical layers continuously add in a concentric manner and press and harden the central nucleus
  • As the lens ages, its weight increases and accommodation decreases
  • The epithelial cells accumulates and leads to loss of transparency
  • With aging the rate of transport of water, nutrients and antioxidants to the lens decrease which potentiates the oxidative processes in cataractogenesis
  • Photo-oxidative insult, potentiated by toxic or sensitizing substances, also play a role in the development of opacities

 

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Clinical Manifestations:

Senile cataracts may be nuclear, cortical or subscapular, affecting different areas of the lens, they may present with different symptoms initially, but the indication for intervention and treatment remains the same.

Broadly may present with:

  • History of painless progressive functional impairment in vision
  • Cataract formation is usually bilateral but can be asymmetric
  • Decreased visual acuity
  • Difficulty in driving, reading road signs and reading fine prints
  • Excessive glare or decreased vision with bright lights

 

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Workup and Diagnosis:

History: Should include duration of visual complaints, patient's ability to meet his/her visual needs and the extent of effect of the deficits; on the daily activities of life.

Inquire about:

  • Location of vision loss (central vs. peripheral)
  • Progressive loss of vision
  • Associated pain (sharp or dull)

Physical exam: The examination should include

  • Visual acuity
  • Direct and indirect ophthalmoscopy: To rule out retinal disease
  • Slit-lamp examination: Detailed visualization of lens opacity
  • Tonometry: To rule out increased Intraocular pressure

Laboratory:

Rarely done, but may be necessary to rule out co-existing diseases.

  • CBC
  • Blood sugar
  • Electrolytes

Pre operative work up:

  • PT
  • APTT
  • ECG
  • Measurements for intraocular lens implantation

Imaging:

  • Ultrasound: Used to rule out posterior segment disease (e.g. ocular tumours or retinal detachment), if the cataract is too dense for direct visualisation of back of the eye

 

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RN/Medical Management:

Only surgical options are available for the definitive treatment of cataracts.

Goals are:

  • Maintain eye comfort
  • Promote early visual rehabilitation

 

General considerations for surgery:

  • Lens removal in cataract patients:
    • Usually recommended when vision change is affecting the patient's activities
    • Surgery is usually done one eye at a time
  • Cataract surgery is usually done under local anaesthesia. Sometimes only topical drops are required
  • Intraocular lens (IOL) implants are inserted at the time of cataract extraction
  • If IOL is not implanted then the patient is prescribed 'strong' glasses or contact lenses to correct refractive error

 

Surgical Options:

There are currently 4 main surgical options for cataract.

1) Intracapsular cataract extraction (ICCE): Rarely done anymore

Method involves extraction of the entire lens, including the lens capsule.

Currently it is indicated in very few cases, such as; for a dislocated lens with Marfan's syndrome.

2) Extracapsular cataract extraction (ECCE)

This method involves the removal of the lens nucleus through an opening in the anterior capsule with retention of the integrity of the posterior capsule.

ECCE advantages over ICCE surgery:

  • A smaller incision ~10-14 mm
  • Complications of vitreous adherence to the cornea, iris, and incision are minimized
  • A better anatomical placement of the IOL is achieved with an intact posterior capsule
  • Intact capsule prevents bacteria and other microorganisms from gaining access
  • Safer choice for secondary IOL implantation, filtration surgery, corneal transplantation, and wound repairs due to intact posterior capsule

3) Manual small incision cataract surgery (MSICS)

A form of ECCE which uses a smaller incision (6-8 mm) and a scleral tunnel that is self-sealing. Results in significantly less astigmatic error.

 

4) Phacoemulsification

99% of cataracts in North America is done with this technique.

Extraction of the lens nucleus is performed through an opening made in the anterior capsule. First, the lens is fragmented using ultrasound energy and then aspirated.

Advantages

  • Usually requires only topical anesthetic and mild sedation
  • Very small incision in the cornea, usually 2-4 mm
  • Usually requires one or even no sutures
  • Rapid healing
  • Rapid visual rehab
  • Better control

 

Lens Replacement:

After the removal of the lens, the patient is referred to as Aphakic (without lens). The lens must be replaced in order to focus light on retina for patient to see clearly.

There are three lens replacement options:

  • Aphakic Eyeglasses: Effective but heavy, peripheral vision limited
  • Contact Lenses: Provide almost normal vision, but needs to be removed occasionally so eyeglasses are still required
  • Intraocular Lens Implants (IOL): A regular approach during cataract surgery, there are certain condition like diabetic retinopathy, uveitis, chronic iritis, neovascular glaucoma, retinal detachment, in which implantation is contraindicated

 

Toxic Anterior Segment Syndrome (TASS):

A non-infectious inflammation caused by a toxic agent after uneventful surgery, and is a complication of anterior chamber surgery.

  • Usually begins less than 24hrs after surgery
  • Presents as corneal edema along with pain and reduction in visual acuity
  • Managed by topical steroids, but may be hard to distinguish from endophthalmiti

Note: There are many potential complications of cataract surgery, some of which can be intraoperative, early and late postoperative.

 

Femtosecond Laser:

It is the newest option where laser therapy is adopted for cataract removal, with fewer complications when compared with the conventional surgeries.

It can be used for wounds, opening of the lens and for the segmentation of cataract; in conjunction with phacoemulsification to remove the lens pieces.

 

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Medications:

Local Anesthetic, (ophthalmic)

  • Proparacaine
  • Tetracaine

Mechanisms:

  • Prevents initiation and transmission of impulse at the nerve cell membrane by inhibiting Na ion channels and stabilizing neuronal cell membranes

Dose:

Proparacaine

Ophthalmic surgery

  • 1 gtt of 0.5% solution in eye every 5-10 mins for 5-7 doses

Tonometry, gonioscopy, suture removal

  • 1-2 gtt of 0.5% solution in eye just prior to procedure

Tetracaine

Anaesthesia of the eye

  • Short-term: 1-2 gtt of 0.5% solution in eye pre-procedure
  • Prolonged: 1-2 gtt of 0.5% solution in eye every 5-10 mins for 3-5 doses

 

Adrenergic, vasopressors, (ophthalmic)

  • Phenylephrine

Mechanisms:

Stimulates alpha adrenergic receptors with weak beta-adrenergic activity, producing

  • Vasoconstriction of the arterioles of the conjunctiva
  • Activates the dilator muscle of the pupil to cause contraction

Dose:

Phenylephrine

Ocular procedures

  • 1-2 gtt of 2.5% or 10% solution and may administer after 10-60 mins as required

 

Mydriatic, cycloplegic and anticholinergic

  • Tropicamide

Mechanisms:

  • Prevents the sphincter muscle of the iris and the muscle of the ciliary body from responding to cholinergic stimulation

Dose:

Tropicamide

  • 1-2 gtt of 0.5% solution 15 mins prior to examination; may be repeated every 30 mins or as needed

 

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Diagnosis and Goals:

Diagnosis:

  • Disturbed sensory perception
  • Risk of injury
  • Self-care deficits related to visual deficit
  • Anxiety related to lack of knowledge about the surgical and postoperative experience
  • Is aware of acute pain that may be related to surgical complications

Goals:

  • To achieve eye comfort and early visual rehabilitation
  • To improve independence and quality of life

 

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Nursing Intervention:

Preoperative goals for client:

  • Make informed decisions regarding therapeutic options
  • Experience minimal anxiety

Preparing the patient for surgery:

  • Explain the procedure and care plan thoroughly to the patient to decrease anxiety
  • Cataracts are commonly removed in ambulatory surgical units
  • Anticoagulants may be held 5-7days before surgery in some cases
  • Some preoperative drugs are given as directed, usually they are:
    • Administered every 10 min for four doses at least an hour before surgery and then on the operating table
  • Antibiotics, steroids, and NSAIDs drops may be administered to avoid infections and inflammation
  • Instruct patients not to touch the eyes, due to risk of infections
  • Obtain eye cultures
  • Assess distance and near visual acuity
  • Note visual acuity in unoperated eye to determine how visually compromised client will be while operative eye heals
  • Assess psychosocial impact of client's visual disability and client's understanding of disease process and therapeutic options

Providing postoperative care:

Post-operative phase

  • Outpatient procedure unless complications occur
  • Antibiotic, anti-inflammatory eye drops
  • 6-8 week follow-up
  • Final glasses prescription

Postoperative goals for client:

  • Understand and adhere to postoperative therapy
  • Maintain acceptable level of physical and emotional comfort
  • Remain free of infection and other complications

Nursing management and assessment:

  • Administer medications as prescribed to relieve pain, nausea and vomiting
  • Notify the doctor if patients complain of sudden pain with increased pulse and restlessness or fever
  • Caution patient against coughing and sneezing to avoid increased ocular pressure

Assess level of comfort and ability to follow the postoperative regimen.

  • Assess visual acuity
  • Assess psychosocial impact of visual disability
  • Assess level of knowledge of disease
  • Assess comfort and ability to comply with post-op treatment

Patient education and self care:

  • Wear glasses or metal eye shield at all times following surgery as instructed by the physician
  • Client and family responsible for nearly all postoperative care
  • Written and verbal instructions before discharge
  • Advise to increase activity as tolerated unless indicated otherwise
  • Advise against rapid movements or bending from the waist, lifting heavy objects straining for defecation, strenuous exercise for atleast 6 weeks
  • Teach how to manage to move around by using one eye, while the other eye is patched for 1-2 days
  • Always wash hands before touching the operative eye
  • Instruct patient and the family members about proper eye drops and ointment installation
  • Advise patient to bring all the medications along with them on follow up visit
  • Bathe or shower cautiously
  • Wipe the operated eye with a clean tissue, from inner canthus outwards
  • Avoid lying on the effected side on the night after surgery
  • Avoid unnecessary radiation
  • Adequate antioxidant vitamins
  • Good nutrition

Ambulatory and home care:

  • Educate on post-operative visual acuity
  • Instruct family to modify activities and environment, such as
    • Remove area rugs
    • Prepare frozen meals
    • Provide audio books

Continuing care:

  • After the removal of the eye patch, the patient may continue to experience visual blurring due to the sutures left in the eye for several days to weeks
  • Patients with lens implants have faster visual improvement
  • Vision is corrected for any remaining near or far sightedness
  • Vision stabilizes and eye is completely healed within 6-12 weeks

Adjusting to the visual change:

  • Prescription for permanent lenses will be determined after 6-12 weeks after surgery
  • Prescription for contact lens can be given 3-6weeks after surgery
  • Encourage patients to wear dark glasses to prevent photophobia

Evaluation: Expected patient outcomes:

  • Vision is maximized
  • Patient can carry out routine activities without any discomfort
  • Minimal to no pain

 

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Nursing Alerts:
  • Small fraction of cataracts can give rise to secondary glaucoma, red eye or severe pain - requires emergent attention
  • Ophthalmologist should be informed of post-operative severe pain
  • Patient cannot drive or operate mechanical equipment for 24 hours after surgery due to the medication given
  • Infection or serious post-surgical bleeding in the eye may lead to a loss of vision; inform physician immediately
  • Most patients with cataracts are elderly
  • Elderly patients with visual impairment may experience:
    • Loss of independence
    • Lack of control over his/her life
    • Significant change in self-perception
  • Elderly patients may need emotional support and encouragement
  • Reassure patient that cataract surgery can be safe and comfortable, with minimal sedation
  • Outpatient surgery is beneficial
  • Elderly patients who become confused or disoriented during hospitalization

 

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References:

Core Resources:

  • American College of Eye Surgeons - Guidelines for cataract practice, 2001
  • Bellan L, Ahmed IIK, MacInnis B et al. Canadian Ophthalmological Society evidence-based clinical practice guidelines for cataract surgery in the adult eye. Can J Ophthalmol 2008;43:S7-57
  • Buhrmann R et al. Foundations for a Canadian Vision Health Strategy: Towards Preventing Avoidable Blindness and Promoting Vision Health prepared for the National Coalition for Vision Health. 2007
  • Compendium of Pharmaceuticals and Specialties (CPS). Canadian Pharmacist association. Toronto: Webcom Inc. 2012
  • Day RA, Paul P, Williams B, et al (eds). Brunner & Suddarth's Textbook of Canadian Medical-Surgical Nursing. 2 nd ed. Philadelphia: Lippincott Williams and Wilkins; 2010
  • Foster C, Mistry NF, Peddi PF, Sharma S, eds. The Washington Manual of Medical Therapeutics. 33rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2010
  • Dirksen, S., Lewis, S., & Collier, I., Heitkemper, M., O'Brien, P., & Bucher, L. (2010). Medical-Surgical Nursing in Canada: Assessment and management of clinical problems (2nd ed.). Toronto: Mosby Elsevier
  • Gray J, ed. Therapeutic Choices. Canadian Pharmacists Association. 6th ed. Toronto: Webcom Inc. 2011
  • Longo D, Fauci A, Kasper D, et al (eds). Harrison's Principles of Internal Medicine. 18th ed. New York: McGraw-Hill; 2011
  • McPhee SJ, Papadakis MA, eds. Current Medical Diagnosis & Treatment. 49th ed. New York: McGraw-Hill; 2010
  • Pagana KD, Pagana TJ eds. Mosby's Diagnostic and Laboratory Test Reference. 9th ed. St. Louis: Elsevier-Mosby; 2009
  • Skidmore-Roth L. ed. Mosby's drug guide for nurses. 9th ed. St. Louis: Elsevier-Mosby; 2011
  • Skidmore-Roth L, ed. Mosby's nursing drug reference. 24th ed. St. Louis: Elsevier-Mosby; 2011

 

Online Pharmacological Resources:

  • e-therapeutics
  • Lexicomp
  • RxList
  • Epocrates Online

 

Journals/Clinical Trials:

  • Javitt JC, Wang F, West SK. Blindness Due to Cataract: Epidemiology and Prevention Ann Rev Public Health 1996; 17: 159-177

 

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Reviewers

EXPERT REVIEWER:
Garfield Miller, MD, FRCSC, Assistant Professor of Ophthalmology, University of Ottawa, The Ottawa Eye Institute, The Ottawa Hospital, Ottawa, ON Canada
.......................................... NURSING EDITOR:
Sadie Sattan, RN, BScN, MN School of Nursing, Faculty of Health Sciences McMaster University/Mohawk College Hamilton, ON Canada

 
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