Photoreceptors are located in the retina of the eye, and respond to light.

 Sensory receptors are the part of the nervous system that detects a stimulus

 Upper and lower eyelids

protect the eye's anterior portion by keeping harmful materials out of the eye

thin membrane that lines the inner surface of eyelids and covers the white of the eye (sclera)

Layers of the Eyeball

Tunics

*Sclera - the outermost tunic made of tough connective tissue

*Choroid- second tunic (vascular layer) composed of a delicate network of connective tissue with many blood vessels and dark brown pigment

*Retina-the innermost tunic, is the eye's actual receptor (nervous)layer

 The outermost tunic (layer) of the eyeball

made of tough connective tissue

Choroid

Second layer (tunic)

vascular layer

many blood vessels and dark brown pigment

innermost layer (tunic)

the receptor of the eye

nervous layer

The retina contains receptor cells for the eye called

Color

sharp central vision

tiny depressed area near the optic nerve that contains the cones.

Fovea is contained within a yellowish spot, the macula

(think of bullseye) outer circle = retina

                           inner circle = fovea

                           center        = macula

transparent layer

a continuation of the sclera

covering the front of the eyeball

 Pigmented section over the front of the eyeball that developes from the choroid

Muscles in the iris control the size of the pupil

black center opening within the eye

allows light to enter

Clear, circular structure made of firm, elastic material that lies behind the iris

Convex shape - adjusts to focus light

- produces aqueous humor (fluid)

- changes the thickness of the lens to focus light for near or far vision 

Watery fluid that fills the anterior and posterior chambers in front of the lens

- maintains the curve of the cornea/refracts light

- constantly produced and drained

soft jelly like substance that fills the vitreous chamber behind the lens

maintains shape of the eyeball/refracts light

Optic Nerve

Signals sent from the photoreceptors travel along nerve fibers to the optic nerve, a nerve bundle which exits the back of the eye

Pathway of light

Optic nerve CN II

Opthalmic nerve CN V

Nerve type song

Sensory or Motor

Both

Some Say Money Matters,

But My Brother Says Big Boobs Matter More

Cranial nerve II

Motor Nerves of the Eye

3, 4, and 6 Make your eyes do tricks

III - Oculomotor Nerve

IV- Trochlear Nerve

VI- Abducens Nerve

3 - Oculormotor Nerve-voluntary and involuntary motor impulses to 4 of the eye muscles

4-Trochlear Nerve - supplies the superior oblique extrinsic eye muscle

down movement

Cranial Nerve VI

6-Abducens nerve - supplies the lateral rectus extrinsic eye muscle

nearsightedness

trouble seeing far

eye strain

light entering into the eye focuses incorrectly

farsightedness (can not see close up)

Normal related to aging

Noticed at about age 45

lense looses ability to focus

the cornea is abnormally curved - causes vision to be unfocused - double vision

farsightedness

NOT due to aging

CN II-optic, sensory nerve, sight

CN III - oculomotor, motor nerve, pupils and EOMs

CN IV- trochlear, motor nerve, EOMs

CN VI- abucen, motor nerve, EOMs, lateral eye movement

CN VII - facial, motor and sensory nerve, facial muscles, blink, taste on anterior tongue

Optic

Sensory

Sight

oculomotor

motor

pupils

trochlear

motor

Extraocular Movements

(EOMs)

abducen

motor nerve

EOMs and lateral eye movement

facial

motor and sensory

facial muscles, blink, taste

Test of Sensory Function

types of tests

Vision

Pupils

EOMs

Snellen

Rosenbaum

abnormal dilatation of the pupil, the result of disease or the use of certain drugs

The test evaluates the functioning of the 6 extraocular muscles and cranial nerves III, IV, and VI

3, 4, and 6 make your eyes do tricks!!

Snellen Chart

Test of visual acuity (optic nerve, CN II)

Client is positioned 20 feet away from the chart and asked to read letters with one eye covered and then the other eye covered

ou = both eyes

od = right eye

os = left eye

tool to detect vision problems resulting from damage to the macula (the central part of the retina or optic nerve II)

Cones/ Color / Fine sharp vision

Damages may be caused by macular degeneration and glaucoma

Cyclogl

Neo-Synephrine

Isopto-Hyscine

Mydriacyl

Homatropine

measures the pressure inside the eye

IOP = intraocular pressure

Normal 10-20

an eye disease that can cause blindness by damaging the nerve in the back of the eye (optic nerve, CN II)

damage to the optic nerve may be caused by a buildup of fluid (aqueous humor) that does not drain properly out of the eye (glaucoma)

what kind of eye drops are used before a tonometry exam?

Cycloplegics- paralyze the eye

these are eyedrops that numb the surface of the eye

Testing cranial nerve VII

facial

Corneal - touching cornea with cotton causes blinking

Blink

Gradual blurred vision

diplopia (double vision)

hazy vision

photosensitivity

glare

difficulty driving at night

white pupils

all activities that increase IOP:

no rapid movement, no exercising, no straining for bowel movement, no sneezing, no coughing, no blowing nose, no bending, no vomiting, no head hyperflextion, no lifting objects >5 lbs. 

-Wear dark glasses in bright light

- eye patch, eye shield, sunglasses for safety

what s/s are important for a post op cataracts surgery paitent to report?

- PAIN

- signs of infection such as yellow or green drainage

Progressive vision loss

"floaters"

- photocoagulation: small laser seals leakage

- vitrectomy - removal of excess vitreous fluid

Surgical coagulation of tissue by means of intense light energy, such as a laser beam, performed to destroy abnormal tissues or to form adhesive scars

Treatment for diabetic retinopathy-

Removal of excess vitreous fluid and scar tissue

what is the macula?

what is in the macula?

the macula is the small, highly sensitive and specialized central area of the retina. 

Rods and Cones

Amsler grid test - card with grid lines (like graph paper)- if lines appear wavy or distorted is postive for macular degeneration

What treatment is available for macular degeneration?

Is it preventative or curative?

Photocoagulation

only preventative

Age related

Genetic

Retinal detachment is:

separation of the retina from the vascular choroid layer - allowing leakage of vitreous humor

flashes of light,

floating black spots,

vision loss

sudden or gradual

painless

cover affected eye with eye patch

avoid activities that increase IOP

Increased intraocular pressure IOP - due to inability of the aqueous humor to drain, causing loss of peripheral vison or increased fluid secretion

Trauma, surgery, tumor, myopia, family history

Goal - to prevent future trauma

Antibiotics - infection

Analgesics - pain

Corticosteroids- edema and swelling

Risk factors - Glaucoma

name 8

1. age
2. infection
3. tumors
4. DM
5. genetics
6. hypertension
7. black ethnicity
8. severe myopia (nearsightedness)

1. open angle glaucoma - chronic, long tearm
2. closed angle glucomoa - acute, just happened 

s/s of glaucoma

name 4

1. slow and progressive peripheral vision loss - tunnel vision
2. halos
3. increased IOP
4. mild eye pain 

1. Beta Blockers - decrease aqueous humor
2. Miotics- cause pupil to constrict by relaxing the pupillary muscle
3. Carbonic anhydrase inhibitors-decrease production of aqueous humor 

LOL

What classification is carbonic anhydrase inhibitors?

used in glaucoma

Nursing considerations before administration?

diuretic

check pt b/p before giving

heart rate

Atropine - dilates pupil

Steroids

What is closed angel glaucoma?

s/s of acute/closed angled glaucoma

name 4

1. rapid onset of blurred or decreased vision
2. halos
3. nonreactive pupils
4. severe eye pain 

what is the priority of care for eye surgeries

name 3

1. prevent increased IOP
2. decrease pressure on suture line
3. prevent infection  

what should be avoided after eye surgery?

name ten activities to avoid

avoid eye strain

    NO:

1. rapid movement
2. exercising
3. straining for bowel movement
4. sneezing
5. coughing
6. blowing nose
7. bending
8. vommiting
9. head hyperflexion
10. lifting objects > 5 lbs. 

Vitamin A

(deficiency leads to impaired night vision)

what technique is used when changing dressings or using eye drop medications?

ASEPTIC

STERILE

1. bleeding
2. severe pain
3. decrease in vision
4. nausea 

brimonidine/timolol = combigan

combination of

alpha adrenergic agonist - causes mydriasis and reduces the production of aqueous humour

beta adrenergic blocker- reducing the production of fluid in the eye

s/s of localized reations from glaucoma medications

name 7

1. burning and stinging
2. headache
3. visual blurring
4. tearing
5. foreign body sensation
6. ocular allergic reactions
7. ocular itching

1. fatigue
2. drowsiness
3. palpations
4. nausea

when are adrenergic blocking drugs contraindicated?

name 5 conditions

1. asthma
2. COPD
3. sinus bradycardia
4. heart failure
5. cardiogenic shock 

Name 2 reasons Corticosteriods are used for treatment of eye

1. inflammatory conditons
2. prevent corneal transplant rejection

Prednisolone 

adverse reactions associated with corticosteroids

name 2

1. secondary ocular infections
2. exacerbation (aggrevate, increase) of corneal infections 

what can prolonged use of corticosteroids cause

name 2

1. increase IOP
2. optic nerve damage 

Antibiotics, sulfonamides, and silver

reactions

Local adverse reactions:

1. occasional transient irritation
2. burning
3. itching
4. stinging
5. inflammation
6. blurred vision

what do mydriatics / vasoconstrictors do?

name 3

1. dilate the pupil
2. constrict the superficial blood vessels
3. decrease aqueous humor

combo drug:

cycloplegics/mydriatics

Use and Name

Use:

Mydriatics cause mydriasis = pupil dilation

Cycloplegics paralyze eye muscle

Atropine (isopto-atropine), homatropin

1. wash hands
2. warm medication
3. cleanse around the eye
4. tilt head back
5. pull down affected lower lid  
6. position dropper, bottle or tuber over lower conjunctival sac
7. have client look at ceiling
8. place drops in center of lower conjunctival sac
9. close eyes
10. apply pressure to the medial (inner) canthus to prevent systemic absorption
11. wait 5 minutes between drugs if different medication