Eye and Ear Medications Overview

Eye and Ear Medications: Chapter Overview

• This chapter covers eye and ear medications, key terms, eye and ear anatomy and conditions, and treatments for each.

Learning outcomes

• Define all key terms related to eye and ear medications
• List five parts of the eye and the function of each structure
• Recall three conditions related to the eye that require treatment with medications and an example of an appropriate medication
• Classify the parts of the ear as belonging to the external, middle, or inner ear, discussing the function of each part
• Recall three conditions related to the ear that require treatment with medication and an example of an appropriate medication

Key Terms

• Aqueous humor is the watery substance in the anterior chamber of the eye.
• Cerumen is earwax.
• Intraocular pressure (IOP) refers to the fluid pressure inside the eye.
• Ototoxicity is damage to the ears caused by drugs.
• Schlemm canal is a circular channel in the eye that collects aqueous humor from the anterior chamber and delivers it into the bloodstream.
• Tinnitus is the perception of ringing in the ears.
• Tonometer is an instrument for measuring pressure, especially within the eye.
• Vertigo is a sensation of dizziness.
• Vitreous humor is a thick, clear gel that fills the space between the lens and the retina of the eyeball.

The Eye

• The sclera is the hard, protective outer layer of the eye.
• The iris regulates the amount of light entering the eye.
• The pupil is the hole in the iris through which light passes.
• Aqueous humor is a watery fluid in the anterior chamber of the eye.
• The cornea is a clear structure covering the iris, pupil, and anterior chamber.
• Vitreous humor is a thick fluid in the posterior chamber.
• The retina is light-sensitive tissue at the back of the eye
• Rods provide black and white vision
• Cones provide color vision
• The optic nerve sends inverted images to the brain for interpretation.
• A tonometer is a piece of equipment used to measure pressure in the eye, or Intraocular pressure (IOP).

Eye conditions

• The eye is vulnerable to disorders, irritations, and infections, including:
• Glaucoma
• Conjunctivitis
• Macular degeneration
• Keratitis
• Chalazion
• Cataracts

Glaucoma

• Glaucoma is the leading cause of blindness, caused by increased pressure in the eye that damages the optic nerve.
• Glaucoma is more prevalent in patients with hypertension, diabetes, migraines, near- or farsightedness, and advanced age.

Types of Glaucoma

• Primary open-angle glaucoma
• It is the most common type
• There is a gradual increase in pressure because the Schlemm canal is obstructed
• There are typically no symptoms
• It can be effectively treated with medications with early diagnosis
• Angle-closure glaucoma
• It is more rare
• Pressure rises very rapidly
• The iris is too small and covers up drainage canals
• Normal-tension glaucoma
• The optic nerve is damaged even though pressure is not elevated significantly
• There are no symptoms
• Treatment involves lowering pressure in the eye through medications or surgery
• Congenital glaucoma occurs in infants due to congenital malformation.
• Secondary glaucoma is glaucoma secondary to another disease, injury, or medications
• It is usually temporary
• Conditions subside with discontinuation of the medication
• Pigmentary glaucoma is where pigment granules break off and lodge in the drainage system.

Glaucoma Symptoms

• Glaucoma symptoms include:
• Headaches
• Eye pain
• Nausea
• Multi-colored halos around lights
• Blurred vision

Miotics

• Miotics increase the outflow of aqueous humor.
• They constrict the pupil.
• Some are cholinergic agonists to decrease IOP.
• Examples are pilocarpine HCL (Isopto Carpine, Pilocarpine HCL Ophthalmic Solution USP), carbachol (Isopto Carbachol), and pilocarpine HCL gel 4% (Pilopine HS Gel).

Prostaglandins

• Prostaglandins increase the outflow of aqueous humor by dilating blood vessels.
• A side effect is a change in pigmentation of the iris (color of eye).
• Examples:
• Bimatoprost (Lumigan)
• Lantanoprost (Xalatan)
• Travoprost (Travatan Z)

Alpha and Beta Blockers

• Alpha Blockers
• They decrease production and increase drainage of aqueous humor
• They have a mild effect on the cardiovascular and respiratory systems
• Examples include apraclonidine H l (lopidine) and brimonidine tartrate (Alphagan P)
• Beta Blockers
• They decrease production of intraocular fluid
• Low doses have no systemic effect
• Examples include betaxolol HCI (Betoptic S) and timolol maleate (Istalol)

Carbonic Anhydrase Inhibitors

• These decrease production of intraocular fluid
• Can be topical or systemic use
• One example is acetazolamide (Diamox and Sequels)

Osmotic Diuretics

• Osmotic diuretics are used for eye surgery to rapidly decrease the amount of aqueous humor.
• One example is Glycerin (Osmoglyn, Ophthalgan Solution).

Medications for Eye Irritations and Infections

• Medications are available for minor eye injuries and irritations, either as drops, salves, or injection.
• Local anesthetics:
• Tetracaine 0.5% solution
• Proparacaine 0.5% solution
• Antimicrobials
• Gentamicin
• Tobramycin
• Erythromycin
• NSAIDs
• Acular (ketorolac tromethamine 0.5 % solution)
• Nevanac (nepafenac 0.1% solution)
• Glucocorticoids
• Dexamethasone (Maxidex suspension, Decadron solution, and ointment)
• Hydrocortone (Hydrocortisone acetate)

Anti-Infectives to treat eye conditions

• Conjunctivitis (pinkeye) is treated with an antibiotic such as gentamicin ophthalmic ointment, and requires meticulous hand washing to prevent spread of infection.
• Styes, which are bacterial infections of oil gland in eyelid, are treated with topical ophthalmic antibiotics or oral antibiotics.

Medications for Eye Examinations

• Cyclopegic mydriatics relax the ciliary muscle and dilate pupils for internal eye examination.
• Ophthalmic anesthetic agents are used to remove foreign objects and do impair the blink reflex.
• Staining agents: use nontoxic, water-soluble dyes to diagnose corneal defects caused by infection or injury.

Miscellaneous Eye Medications

• Immunomodulators increase tear production.
• It may take up to 6 months to see maximum benefit
• Examples: Restasis and Xiidra
• Macular degeneration medications slow progression of the condition.
• Examples: Ranibizumab (Lucentis) and aflibercept (Eylea)

Outer Ear

• The pinna is the visible part of the ear and the external auditory canal
• It protects middle and inner ear
• It Collects sound and funnels it through the canal
• Glands in external canal secrete cerumen to protect inner ear from damage, infections

Middle Ear

• The tympanic membrane (eardrum) separates outer ear from middle ear
• The auditory ossicles (malleus, incus, stapes)
• The middle ear cavity is the hollow area containing ossicles
• The eustachian tube connects ear and throat, equalizes pressure on both sides of tympanic membrane

Inner Ear

• The oval window is located behind the stapes and vibrates when bone strikes it
• The round window Serves as pressure relief valve
• The cochlea helps with hearing
• The semicircular canals help with balance
• The vestibule helps with balance

Ear Medications

• Medications deposited into the outer ear flow toward eardrum
• If eardrum ruptured, medications should be used under strict medical supervision
• Infections
• Otitis externa (swimmer’s ear)
• Otitis media (inner ear infection)

Otic Antibiotics

• Otic antibiotics include
• Acetic acid and aluminum acetate otic (Domeboro Otic)
• Ofloxacin otic (Floxin)
• Acetic acid (Vosol)

Medications for Ear Infections and Pain

• Antibiotics/glucocorticoid combination drugs are used for swimmer’s ear to reduce inflammation.
• Examples include Ciprodex and Cortisporin
• Systemic antibiotics are required for inner or middle ear infections.
• Examples include Amoxicillin, Augmentin, Bactrim, and Ceclor
• Pain medications can treat infection or trauma pain.
• One example is Antipyrine and benzocaine

Impaction of Cerumen

• Impaction of cerumen can cause decreased hearing and pain
• It can trap bacteria
• Mineral oil, cerumenolytics, and hydrogen peroxide used to decrease amount of wax

Motion Sickness

• Motion sickness is the ear’s inability to determine body’s position relative to its motion
• It is treated with tablets or transdermal patches, like transdermal scopolamine
• It is recommended to take 20 to 60 minutes prior to travel
• Vertigo: Dizziness is treated with an anticholinergic drug like Meclizine

Medications and Ototoxicity

• Many drugs cause damage to ears, or ototoxicity.
• Symptoms of damage to ears include:
• Tinnitus
• Hearing loss
• Severe headache
• Ataxia
• Balance disturbances