- cataracts, macular degeneration and glaucoma

Most common causes of chronic visual loss in the US

- located behind the cornea and in front of the lens and iris

- contains aqueous humor which maintains intraocular pressure and corneal shape, provides nutrients to lens and cornea

Anterior chamber

- produced by the epithelium of the ciliary body

- circulates posterior chamber --> anterior --> trabecular meshwork --> canal of Schlemm --> episcleral veins

- also uses uvealscleral tract

(straight to veins through muscle)

Aqueous humor

- time it takes to turn over entire volume of aqueous humor

100 minutes

- as opposed to the risk involved with elevated intraocular pressure (>21 mm Hg), some people with normal pressure can develop this condition

normal-tension glaucoma

- increased aqueous humor pressure also increases the pressure with this other eye fluid

Vitreous humor

- disease that usually occurs with elevated intraocular pressure that preceeds optic nerve damage

- two types (open angle vs narrow angle)

- can be slowly progressive (open) or acute (narrow)

Glaucoma

- most common type of primary glaucoma

- slowly progressive, usually involves both eyes

- over the course of disease, eye effects may differ

- 90% of adult glaucoma (2.2 mil)

- caused by outflow obstruction of aqueous humor due to degenerative changes in trabecular meshwork, canal of Schlemm, venules

Primary open angle glaucoma

- first effect of open angle glaucoma

- usually missed due to the prevalance of central visual field (computers, tv's, books)

Peripheral visual field loss

- gold-standard for measuring intraocular pressure

- requires anesthetic to be administered to the eye prior to testing

- test involves touching the tool to the surface of the eye (pupil)

Contact Tonometry

- blows a puff of air at the eye

- less accurate than contact version

- requires significant practice to do right

- usually overestimates intraocular pressure

Noncontact tonometry

- intraocular pressure >21 mm Hg

- increase in optic cup-to-disk ratio

- optic cup-to-disk ratio > 50% (vertical dimension)

- cup-to-disk ratio in one eye > 20% larger than other eye

Cause for referral to an ophthalmologist

- the contents of the optic cup that make it white on exam

- these cells increase in number in an eye with optic nerve degeneration due to glaucoma

Glial cells (astrocytes)

- ophthalmologic emergency

- most common in women 55-70 and hyperopic people (far-sighted) due to shallow anterior chamber

- less common than open angle

- caused by mechanical blockage of aqueous outflow channel (between iris and trabecular meshwork)

- usually only involves one eye

Acute angle closure (narrow angle) glaucoma

- short-lived or rapidly progressive

- intraocular pressure may exceed 50-60 mm Hg

- sudden onset of excrutiating orbital pain (also temple or brow), nausea and vomiting

- blurred vision, foggy vision, colored halos around light

- non reactive (fixed) and mid-dilated pupil due to ischemic ciliary muscles

- ciliary flush ("red eye" around limbus)

- papilledema on fundoscopic exam

- blindness

Signs and symptoms of narrow angle glaucoma

- dilation of pupil (night-time, intentional dilation, stress)

- use of certain meds (anticholinergics or sympathomimetics)

- excessive sympathetic response

Situations that precipitate acute glaucoma

- Conjunctivitis (bacterial, viral, environmental)

- anterior uveitis (inflamed iris and/or ciliary body)

- acute narrow angle glaucoma

- acute corneal trauma or infection (contacts, burns from UV, foreign bodies, bacterial or viral infection)

Differential for "red eye"

- blurred vision that doesn't disappear with blinking

- pain, photophobia

- halos around point light source

- ciliary flush

- corneal opacity

- pupil problems (size, reaction to light)

- shallow anterior chamber

- increased intraocular pressure

- sudden proptosis

Danger signals that suggest sight-threatening disease

(refer to ophthalmologist)

-Would iritis or conjunctivitis (keratitis) respond to a test where the affected eye is closed and the examiner shines a light in the good eye and the patient experiences pain in the bad eye?

Iritis (due to pupillary response)

- visual acuity

- pattern of redness

- conjunctival discharge

- transilluminate cornea

- use fluorescein to stain corneal epithelium

- depth in anterior chamber

- pupil size, shape, sensitivity to light

- intraocular pressure

- assess for proptosis

Steps for evaluating red eye

- this angle of the anterior chamber produces a shadow on exam from the side of the eye

Narrow angle (due to iris shadow)

- blurred vision

- pain

- photophobia

- halos

- ciliary flush

- conjunctival injection

- corneal haze

- nonreactive pupil

- shallow anterior chamber

- high intraocular pressure

Acute Glaucoma

- blurry vision

- pain

- photophobia

- ciliary flush

- conjunctival injection

- small/irregular pupil

- low intraocular pressure

Acute irdocyclitis

- blurry vision

- pain

- photophobia

- exudation (cloudy fluid)

- ciliary flush

- conjunctival injection

- corneal haze

- discharge

- + cobalt blue eyedrop exam

Keratitis (cornea)

- cloudy fluid (exudation)

- conjunctival injection

- significant discharge (pus)

Bacterial conjunctivitis

(pink eye)

- exudation in both eyes

- head cold, fever

- conjunctival injection

- corneal haze

- discharge

- preauricular nodes

Viral conjunctivitis

- itching

- both eyes

- white nodules

- discharge

- conjunctival injection