Pathophysiology, Chp. 15 - Disorders of the Eyes, Ears, and Other Sensory Organs

The Snellen chart

The eye's intraocular pressure by checking the resistance of the cornea. This can be used to check for conditions like glaucoma.

Near-sightedness, caused by having the eye too long and makes it hard to see things far away.

Far-sightedness from a short eyeball. Where the image is focused behind the retina which causes a hard time seeing objects up close.

Far-sightedness associated with aging. The loss of elasticity reduces accommodation.

The ability of the eye to focus on the image; making it sharper.

Conjunctivitis: a superficial inflammation or infection involving primarily the conjunctiva.

Pinkeye: an infection of the sclera and eyelid.

A stye - involves a hair follicle on the eyelid; usually a staph infection.

It's an inflammation of the cornea, usually caused by an infection. There's an increased risk of ulceration and scarring which can interfere with vision.

It collects aqueous humour from the anterior chamber and delivers it to the veins of the eyeball.

Fluid produced from the ciliary body which flows into the anterior chamber.

Located at the base of the cornea; is responsible for draining the aqueous humor.

Due to increased intraocular pressure from excessive accumulation of aqueous humour.

Acute: where the angle between the cornea and iris is decreased (there's an enlargement of the lens), this ends up blocking/slowing the flow of aqueous humour in the anterior chamber, increasing intraocular humour.

Chronic: mostly happens in older people. Where the canal of Schlemm becomes obstructed and the outflow of aqueous fluid is diminished. Leads to ischemia and damages to the retinal cells. Damage is irreversible and will lead to blindness.

In older people - usually beginning at age 50.

- increased intraocular pressure

- corneal edema

- altered light refraction = blurred vision

- appearance of "halos" around light

- eye discomfort

development abnormality, aging or scar tissue.

- pain and nausea

- headache

- blurred vision

- bulging cornea

- pupil unresponsive to light

- eye drops to reduce aqueous humour

- drugs to reduce intraocular pressure

- trabeculoplasty/trabeculectomy if unresponsive to increase drainage

- surgery to open the Canal of Schlemm

- laser iridectomy

When the lens becomes cloudy and thus interferes with the transmission of light. Cloudiness is caused by the build up of proteins in the lens. This may be caused by degeneration related to aging or metabolic abnormalities.

Congenital: usually a result of maternal infection such as rubella or toxoplasmosis.

Traumatic: due to a blow to the eye.

Age related: from as you get older.

Secondary: due to a disease such as diabetes.

Your blurred vision progresses over your entire field of vision and becomes darker over time.

The damaged lens can be removed and replaced by an artificial one. A peripheral iridectomy may be included to prevent postoperative glaucoma.

A cataract.

Rods - motion, black-and-white vision

Cones - colour, central vision

In the macula.

The fovea, containing only cones and is at the very center of the macula.

It's an acute problem that may occur due myopia, degeneration with aging or scar tissue.

- area of black

- floaters that won't go away

- a blind spot called a "dark curtain"

Scleral buckling, laser therapy to close holes and reattach the retina

Where the macula and fovea centrals (responsible for central vision) degenerate and thus our central vision becomes blurred and eventually lost.

Conduction deafness: when sound is blocked in the external or middle ear. Usually from obstruction of wax or foreign object in ear canal. Possibly scar tissue or adhesions.

Sensorineural deafness: due to damage to the organ of Corti or the auditory nerve. Can be from infection, ototoxic drugs, head trauma, congenital deafness, sudden loud noise or prolonged exposure to it.

amplify sound and improve hearing capacity.

cochlear implants

middle ear cavity.

Otitis media

- pain meds first

- antibiotics if symptoms don't subside

- decongestants

- tympanoplasty if damage is done

A cyst like mass (which may develop from chronic otitis media).

A mass is formed in the middle of the ear cavity. This eventually erodes the ossicles and surrounding bone leading to hearing impairment. May effect hearing, balance and the function of facial muscles.

Otitis externa

An imbalance of bone formation and resorption. Conduction of sound into the cochlea is blocked.