Chapter 40 Agents Used in the Treatment of Conditions of the Eye.

Chapter 40

Agents Used in the Treatment of

Conditions of the Eye

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The Eyes

Organ of vision Retina Uvea Sclera and cornea Light reacts off the retina

The Eyes

Images are transmitted by the optic nerve

Interpreted by the brainAnterior and posterior chambersAqueous humor

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Ophthalmic AgentsFacilitate eye examinationsTreat

Infection Inflammation Glaucoma

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Sympathomimetic MydriaticsProduce

Pupil dilationIncrease aqueous humor outflow

Decrease formation of aqueous humor

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Anticholinergic MydriaticsBlock sphincter iris muscle

Produce pupil dilationAllow for measurement of refractive errors

Cause vision and focus problems

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Ophthalmic Anti-infectives

AntibioticsAntifungalsAntiviralsAntiseptics

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Ophthalmic Anti-Infectives Eye is susceptible to bacterial, viral, and

fungal infections Some require mild therapy Some require aggressive treatment Diagnosis is important Antibiotics Antifungals Antivirals

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AntibioticsMonitor for hypersensitivitySystemic therapy should be

given in addition to topical agents

Topical agents administered as eye drops

Antibiotics

Antibiotic eye drops contain agents not usually given systemically

Agents are usually a combination of drugs

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Antifungal AgentsNatamycin treats blepharitis,

conjunctivitis, and keratitisApplied to conjunctival sac

frequently

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Antiviral Agents

Can cause severe discomfortMay lead to scarring and vision

loss if not treatedDrugs usually block reproduction

of viral agent

Antiviral AgentsAlters normal DNA synthesisMost common is herpes

simplex and varicella zoster viruses

Adverse effects could include burning, irritation, hypersensitivity, pain, photophobia, or toxicity

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Nursing ConsiderationsAlways monitor effectiveness of

therapyMonitor for signs of toxicityUse proper instillation techniques

and teach to patientsWash handsAvoid contamination of tip of

applicator

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Other Eye Agents

Local anestheticsCorticosteroidsGlaucoma agents

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Local Anesthetics

Anesthetize the eyeReduce the blinking reflex

To removeChemicalsForeign objects

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Corticosteroids Useful for eye allergies Useful as an additive agent in eye

infections Reduce

InflammationPain

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Nonsteroidal Anti-inflammatory Agents

Four are available for ophthalmic use Inhibits pupil constriction Reduce edema and inflammation Relief of pain May cause hypersensitivity Some may not be used in patients

who wear contact lens

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Glaucoma

Increased intraocular pressure (IOP)

Aqueous humor buildup Pressure pushes the vitreous

humor against the retina Constant pressure destroys the

retina, which leads to blindness

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GlaucomaNarrow-angle glaucoma is

caused by the iris occluding the anterior chamber structures

Dilation of the pupil could cause acute attack

Treatment is surgeryCreates a new openingOpen-angle more common

GlaucomaNo change in the chamber angleLocal degenerative changesSymptoms appear after severe

damage to optic nerveGoal is to decrease production

and increase outflow

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Antiglaucoma Drugs

Reduce the formation of aqueous humor Carbonic anhydrase inhibitors Osmotic diureticsBeta-adrenergic blocking agents

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Carbonic Anhydrase Inhibitors

Inhibits the enzyme carbonic anhydrase

Reduces production of aqueous humor

Decreases intraocular pressure Treatment of open-angle glaucoma

and pre-operative management of acute narrow-angle glaucoma

Carbonic Anhydrase InhibitorsUsed with topical therapyDiureticsIncreases excretion of sodium,

potassium, bicarbonate, and water

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Osmotic Diuretics

Rapidly reduces production of aqueous humor

Treats acute attacks of narrow-angle glaucoma and preparation of surgery

Not for chronic use

Osmotic DiureticsExtreme caution in patients with

renal impairmentMay cause headaches, nausea,

and vomitingGiven orally or parenterally

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Beta-Adrenergic Blocking Agents

Applied topicallyLowers ocular pressure by

reducing formation of aqueous humor

Little effect on pupil size or visual acuity

Beta-Adrenergic Blocking AgentsUsed alone or in combination

with other drugsCan be absorbed systemicallyCan interfere with treatment of

patients with airway disease and congestive heart failure

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Antiglaucoma DrugsIncrease aqueous humor outflow

Direct-acting mioticCholinesterase inhibitors: para-sympathomimetics

Prostaglandin-inhibiting agentsSympathomimetics agents

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Direct-Acting MioticsMimic action of acetylcholineConstricts pupilContracts ciliary muscleFacilitates outflow of aqueous

humor

Direct-Acting MioticsDrops, gel, or Ocusert

Therapeutic SystemAdverse effects include reduction

in visual acuity, flushing, sweating, gastric distress, diarrhea, and headache

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Miotics That Inhibit Cholinesterase Activity

Prevents enzymatic destruction of acetylcholine within the eye

Inhibits the enzyme cholinesterase

Greater acetylcholine activity

Miotics That Inhibit Cholinesterase Activity

Production of miosisContraction of the ciliary muscleMore toxic and longer lasting

than direct-acting mioticsReserved for use in patients that

do not respond to other therapy

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Miotics That Inhibit Cholinesterase Activity

Adverse effects are both local and systemic

Systemic effects - salivation, urinary

incontinence, sweating, diarrhea, and muscle

weakness

Miotics That Inhibit Cholinesterase Activity

Local effects - stinging, burning, lacrimation,

lens opacities, and ocular

inflammationMonitor for toxicityAntidote is atropine sulfate or

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Agents That Effect Formation and Outflow of Aqueous Humor

Prostaglandin-inhibiting agents - stimulates outflow by inhibiting prostaglandin synthesis; increases vascular permeability - used prior to eye surgery, open-angle glaucoma, and ocular hypertension - remove contact lenses - latanoprost can cause eye color changes

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Agents That Effect Formation and Outflow of Aqueous Humor

Sympathomimetic agents - stimulate adrenergic receptors in

the eye - reduces aqueous humor production - with extended use, may rebound

and increase production

Agents That Effect Formation and Outflow of Aqueous Humor

Used in combination with a miotic - use with caution in elderly and patients with hypertension, diabetes, hyperthyroidism, or heart disease - exaggerated effects may occur if

taking MAOI’s or other antidepressants - used only in open-angle glaucoma

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Nursing Considerations Assess the patients eyes Teach proper administration of eye

medications Use eye patches as appropriate Ensure medication is used properly Assess for safety Teach patient to continue treatment as

long as prescribed Throw away contaminated medications