Sclera- white of the eye
Cornea- clear structure bends light aka the lens
Iris- muscle pupil size, color of eye brown blue gray, whatever
Fovea- large amount of cones
aqueous humor- formed in posterior chamber
OS left eye
OD right eye
OU both eyes
Rods low light or night vision
Cones bright light color- detail
The anterior compartment is divided into 2 chambers, posterior chamber produces acrous fluid
Fluid flows into anterior chamber and laves through the filtration system
How does light travel?
Light passes through the cornea, the anterior and posterior compartment, the pupil, lens and vitreous humor
Impulses from the left half of eye are carried to the left side of the brain
Impulses from the right side/half of each eye are carried to the right occipital lobe
Things to look for
Ptosis-drooping
Drainage
Lesion
Sclera color
Nystagmus- oscillating movement of eyeball
What is their eye sight on the Snellen chart?
DX tests
Direct and indirect ophthalmoscopy- shows structures in eye
Tonometry- measures IOP (glaucoma test- air puff test)
Slit lamp examination (extremely bright light
3 types of problems- refractive, infections, and diseases & trauma
Refractive
emmetropia- normal
myopia- nearsighted eyeball too long, light focus in front of retina
hyperopia farsighted eyeball too shallow light focus behind retina
astigmatism- light scattered not focused cornea not shaped right
presyopia-occurs with again lens become less able to change shape (accommodation)
How to correct refractive errors
Lenses, glasses or contacts
SERGERY- lASIK, CK
Lasik- cornea is reshaped so that light is focused correctly using a laser
CK treats hyperopia using high frequency radio waves.
LOW VISION BLINDNESS
Low vision – best corrected vision at 20/70 – 20/200
Blindness – best corrected 20/400 to no light perception
Legal blindness, Best corrected in best eye no grater than 20/200 or widest visual field diameter 20 degrees or less
Infections,
Conjunctivitis- pink eye- itching burning redness, photophobia, drainage
Treatment based on cause- antibiotics for bacterial
Prevention of spread don’t share personal high gene items, hand washing important
Hordeolum (sty) inflammation of lower eye lid possible bump treat with warm compress all to drain
DISEASES Of the eye- glaucoma, cataracts, Macular degeneration, diabetic degeneration
Glaucoma- group of diseases that can damage the eye’s optic nerve and result in vision loss and blindness (increased interocular pressure results in vision loss or blindness)* normal IOP 10-21 mmHG
Normal drainage of aqueous fluid through the canal of schlemm depends on intact drainage system and an open angle between iris and cornea
IOP is determined by rate of aqueous humor production and drainage
Categories of glaucoma-
Open angle (most common) - making too much fluid
Chronic, normal tension, ocular hypertension
Closed angle- making normal amount of fluid but can’t drain it,
Acute AACG sub acute, chronic
Signs and symptoms
It’s a silent disease
Rarely causes symptoms
Subtle loss of contrast
Gradual loss of peripheral vision
Can develop in one or both eye
*halos around lights very common
Headache
Who is at risk?
Associated with ageing
Family history
African Americans
Leading cause blindness in blacks and 2nd in whites
Management
Can not be cured
Treatment aimed at preventing progression
2 primary mechanisms for lowering IOP
1. Decrease the amount of aqueous humor coming info eye
2. Increase the amount of fluid going out.
DRUGS
parasympathomimetrics (miotocs) pilocarpine, carbachel, physostigmine
Constricts pupils, widens exit route of fluid
Side effects most local- brow pain, visual blurring, and conjunctivitis decreased nigh vision
Systemic effects- salivation, lacrimation, urinary, incontinence, diarrhea, gi cramping emesis
Sympathmimetics(midriatics) dipivefrin and epinephrine- results in increased outflow
and decreased production of aqueous fluid which lowers IOP
Side effects- burning, eye pain lacrimation,
Systemic- tachycardia and hypertension
Beta Blockers- betaxolol and timolol
Block beta adrenergic receptors resulting in reduction of aqueous humor formation
Side effects- local burning and discomfort decrease corneal sensitivity
Systemic headache bronchospasm, dizziness
Carbonic Anahydrase inhibitors- dorzolamide(trusopt)
Increase renal excretion of sodium potassium and water
Symptoms GI upset, Malaise, Renal Stones, aplastic anemia caution sulfa allergy
Prostaglandins- latansprost (xalatan) bimatoprost
Single daily dose
Increase drainage
Side effect may change color of the iris
Well tolerated, a few local effects like burning and itching
Osmotic Diuretics (acute treatment) manaitol and glycerin
Used to treat acute glaucoma episodes and before and after surgery promotes
Dieresis by causing a shift of fluid from anterior chamber into blood stream
Surgical treatment
Trabeculoplasty- laser surgery which makes 50-100 burns in the trabecular meshloury to improve outflow and drainage
Laser iridotomy, creates new opening for aqueous fluid to leave eye (removes small piece of sclera)
CATARACTS- clouding of the lens, usually caused by again but can be trauma, certain drugs, diabetes, and ultraviolet light or congenital
Most common eye disorder other then reflective errors
50-70% of older adults have cataracts
Manifestations
Gradual blurring of vision, light scattering dipolopia
DX
Decreased visual acuity
Direct visulation
Only cure is surgical removal of old lens
Extracapsular extraction: nucleus, cortex and anterior lens is removed
IOL implants done in 90%
Caring for the client undergoing cataract surgery
Pre op- mydratic and cyclopengic eye drops and antibiotic eye drops, sedatives may be used
Post op- recovering from sedation, eye shield, analgesic, antibiotic/antiflammatory eye drops
Teaching- no blending at waist, don’t lift heavy objects, not a lot of pain, itching or burning call if you have them, sight should be better every day where patch at night
Complications
Hemorrhage, leads to increased IOP
Infection
Vitreous humor less
IOL malposition
NO shot, no stitch no patch
3mm incision
phacoemulsification to break the lens apart
Foldable IOL
Only local anesthesia
No sutures or patch needed
Macular degeneration
Age related, affect central vision most common cause of blindness in American s older then 60
2 kinds
DRY AMD chronic non exudative more common
WET AMD abrupt onset
There is no cure, use bright light and magnification to help see items
Laser for wet AMD to seal blood vessels
Macular degeneration can be frustrating for individuals because it affects everyday activities such as reading and driving
Diabetic Retinopathy
Due to microvasular changes
Early stages
Retinal vessels leak fluid cauing swelling and deposits later retinal blood vessels are destroyed new vessels form
Manifestations
Includes floaters, spoty or hazy vision or complete visionloss
Retinal detachment- ermergancy
Retinia pulls away from the choroids layer
Must be surgically corrected
Signs and symptoms of RD
Flashes of light
Cobwebs
Floaters
Shade or curtain over eye
Treatment
Surgical reattachement with scleral buckle which brings two layers of the retina togherher
Post op- usually done on outpatient basic
Instruct pt on signs and sx of increased IOP and infection
Avoid activies that could increase IOP
Ocualr trauma
Foreign bodies, corneal abrasion sever pain and photophobia
Chemical burns