Palpebral Fissure- open space between eyelids, lower lid is limbus, canthus is corner of eye where eyelids meet

Caruncle- Flesshy mass containing sebaceous glands

Meibomian glands- modified sebaceous glands, creates seal when lids are closed

Six muscles attach eye to orbit 

4 of these are straight (rectus)- superior, lateral, medial and inferior

Movement of these muscles are stimulated by three cranial nerves; 

VI- abducens-innervates lateral rectus

IV- Trochlear0 innervates superior oblique 

III- oculomotor- innervates all the rest

Outer layer- Sclera- tough protective white covering

Cornea- covers iris and pupil, bends (refracts) incoming light, transparent

Middle layer- Choriod- vascularized, delivers blood to retina,Ciliary body controls thickness of the lens. Iris-controls amount of light admitted to retina. Pupil- round, regular, stimulation thru nerve III causes constriction(parasympathetic), sympathetic branch stimulates dilation

Lens- bulges when focused on near objects, flattens for far objects

Inner Layer- Retina- visual receptive layer of eye, waves are changed into nerve impulses. Retinal vessels contain paired artery (bright red)

and vein

Macula- receives and transduces light

Fovea Centralis- Sharpest and keenest vision

Pupillary Light Reflex- normal constriction of pupils when bright light shines on retina. When one eye is exposed to light a direct light reflex occurs (constriction)  as well as consensual light reflex ( simultaneous constriction of the other pupil). 

1. Cataract-lens opacity, clumping of proteins

2. Glaucoma- Increased intraocular pressure, Scotoma is a blind spot surrounded by area of normal/decreased vision occurs w/t glaucoma

3. Macular Degeneration- cells in macula breakdown, loss of central vision, most common casue of blindness. Women more affected then men.

Photophobia- inability to tolerate light

Strabismus- deviation in axis of eye

Diplopia-perception of 2 images of single object

Tests for Visual Acuity

Normal is 20/20

The larger the denominator, the poorer the vision

20/30-1 means 20/30 missing one letter

20/30 means you can read at 20 feet what the normal eye can see from 30 ft away.

A measure of peripheral vision. Compares patients peropheral vision with your own. You and patient cover opposite eye (looks same when facing eachother), slowly advance in their periphery in several directions.

Normal results are 50 degrees up, 90 temporally, 70 down and 60 nasally. Suggests peripheral field loss if patient doesn't see object as examiner does.

Diagnostics Position Test

Sceral Icterus- a yellowing of the sclera, indicates jaundice

Ptosis- drooping of upper lid

Anisocoria- Pupils of two different sizes

Enlarges your view of the eye to inspect the media and ocular fundus (internal surface of retina) Look through hole and adjust to focus. Unit of strength in each lens is diopter. Black numbers indicate positive, focus on objects nearer to opthalmoscope, Red numbers show a negative diopter and are for far away objects. Aperture is where you view eye

Normal vision diopter is at 0, moving it compensates for near/farsightedness (red=near) (black=far)

Red glow filling person's pupil, this is a reflection of opthalmoscope light off inner retina. Adjust lens to 6+ to note any opacities in media (should be none)

Cataracts appear as opaque black areas against red reflex. 

Myopia- nearsighted, light rays focus in front of retina

Hyperopia- Farsighted, light rays would focus behind retina

Absent pupillary light reflex (blinking) after 3 weeks indicates blindness

Criteria for Blindness 

1. Age 3 yrs- vision 20/50 or greater

2.Age 4yrs- 20/40 or greater

3. Difference between 2 eyes is one line or more

Many infants have an epicanthal fold (excess skinfold on inner corner of eye)- give a false sign of malalignment termed pseudostrabismus

Lacrimal glands not functional at birth

Ectropian- lower lid dropping away

Entropian- lower lid turning in

Pingueculae- show on sclera as yellow, elevated nodules

Pseudoptosis- upper lid is elongated as to rest of lashes

Arcus Senilis- Seen around cornea, gray white arc around limbusm due to lipid buildup, no effect on vision

Xanthelasma- raised yellow plaques on lids at inner canthus, more in women (50's)

Involves optic nerve damage and visual field changes

Open Angle- drainage channels become clogged, leads to inocular pressure buildup.

Closed Angle- drainage canals are blocked or covered by outer edge of iris, comes on suddenly

True disparity of eye axes, Constant malalignment is termed tropia

Estropia- inward turning of the eye

Exotropia- Outward turning of eye

Phoria- mild weakness, 

Esophoria- nasal (inward) drift

Exophoria- temporal (outward) drift

Periorbital Edema- lids are swollen and puffy, occurs with local infections, crying, congestive/renal failure, allergy

Exophthalmos- protruding eyes

Enophthalmos- sunken eyes- loss of fat in orbits and dehydration

Ptosis- drooping of upper lid from neuromuscular weakness ,oculomotor cranial 3 nerve damage or sym nerve damage

Upward Palpebral Slant- normal is asians, indicates down syndrome in caucasian

Blepharitis- inflammation on eyelids

Chalazion- beady nodule protruding on lid, infection or retnetion of cyst on meibomian gland

Hordeolum- Stye, localized staph infection in hair follicles

Daryocystitis- inflammation of lacrimal sac- infection of lacrimal gland

Monocular Blindness- when light is directed to blind eye no response, when light is directed to normal eye both eyes constrict

Mydriasis- Dilated and fixed pupils, stimulation of sym system

Miosis- Constricted and fixed pupils

Horner's Syndrome- small, regular pupil that doesn't react to light and accommodation, lesion of sym nerve.

Cranial Never 3 Damage- dilated pupil with no reaction to light or accommodation with oculomotor nerve damage

Lesion in globe or optic nerve- yields one blind eye or unilateral blindness

Retinal Damage- Macula- central blind area (diabetes)

Subconjunctival Hemorrhage- red patch on sclera

Iritis- Circumcorneal redness-deep dull halo around iris and cornea

Pterygium- triangular opaque wing of bulbar conjunctiva overgrows toward center of cornea.

Corneal Abrasion- blunt eye injury-top layer of corneal epithelium removed

Hyphema-blood in anterior chamber is a result of herpes zoster infection, also occurs with blunt trauma

Hypopyon- Purulent matter in anterior chamber occurs with iritis and inflammation