Opthalmic Disorders Lecture Flashcards
What is the purpose of the eyelids?
Natural defense mechanism/protective elements
Limits damage to anterior surface of eye
Coat surface of eye with lubricating tears
Help in tear removal towards nose and drainage pathways
What is the purpose of the tear layer?
Lubricates ocular surface
Removes debris on surface
Provides antimicrobial protection
Reflex tearing
What are the three layers of the eye?
Lipid layer: prevents evaporation
Middle Aqueous layer: primary wetting layer
Inner mucin layer: helps other two layers adhere to eyed
What is the lacrimal drainage system?
highly vascularized system of epithelium leading form lacrimal sac to nasal cavity
Site of systemic absorption of topically applied medication s in the eye
What is the cornea?
Clear layer Innervated Avascular Refracts light 5 layers --> impact PK of meds
What is the sclera?
Tough, rigid/collagenous layer –> gives the eye its’ shape
Keeps internal structure in place
Epithelial layers contain vascular and lymphatic systems
What is the iris?
Visible, colored portion of the eye located in the anterior segment (behind the cornea)
Regulates amount of light striking the retina
What is the pupil?
Diameter controlled by 2 opposing muscles within the iris (sphincter and dilator)
What does the sphincter do?
Closes through parasympathetic stimulation (rest/digest)
–> PGs lead to constriction
What does the dilators do?
Open through sympathetic stimulation (flight/fight)
What is conjunctiva?
Thin membrane that covers the inner surface of the eyelid and the white part of the eyeball (sclera)
What is conjunctivitis?
Inflammation of the conjunctiva –> eye appears red
What is the retina?
Responsible for initial processing and transmission of light signals
What does the epithelium provide?
Vital electrical support to retina
What does atrophy in pigment epithelium leads to?
Macular degeneration
Who is dry eye common in and what causes it?
Older patients and females
Caused by eye lid defects, dry/dusty environments, various medical conditions, refractive surgery patients and MEDS
What meds cause dry eye?
Drugs with anti-cholinaric properties (antihistamines, antidepressants)
Decongestants
Diuretica
Beta blockers
What are sign and symptoms of dry eye?
Excessive tearing Watering Burning Scratch/gritty sensation White/mildly red eye
What is the treatment goal of dry eye?
Alleviate and control dryness to relieve symptoms and prevent damage to the eye tissue (corneal surface)
What are some non-pharmacological treatments of dry eye?
Avoid dry dusty environments Position away from vents Humidity air Limit time focusing on a computer Water intake Wear eye protection Cold compresses
What are ocular lubricants?
Mainstay of OTC treatment for dry eyes because it reduces evaporation, replensishes/stabilizes tear-film, protect corneal/conjunctival cells, and reduce tear evaporation
Vary by viscosity/pH/preservatives
The worse the dry eye…
The higher the viscosity needed to treat
What is the use of artificial tear solutions?
Used for mild cases
Stabilized tear film and decreases tear evaporation
Start takid BID
What is the use of artificial tear gels?
Used for moderate to severe cases
Mildly more viscous than solutions
Increase viscosity could potentially mess with vision
What is the use of artificial tear ointments?
Severe cases White petrolatum/mineral oil/lanolin BID Can significantly alter vision Benefits: retained in eye longer and enhanced integrity of tear film
What are artificial tear side effects?
Stinging
Blured vision
Preservative risk
What are preservative issue ophthalmicly?
Must be steril
Used to destroy or limit bacterial growth
Can be toxic to ocular tissue
Increased frequency of use increases toxicity risk
What ophthalmic products do not require preservatives?
Unit dose kits
One time use
What are the three types of conjunctivitis?
Allergic (itching)
Viral (watery discharge)
Bacterial (mucoid discharge)
What are the hallmarks and signs and symptoms of allergic conjunctivitis?
Itching, seasonal allergic rhinitis and clear, watery discharge
Itching, swollen or puffy sensation to lids, redness and bilateral
What are treatments for allergic conjunctivitis?
Remove offending allergen
Cold compressions
First line: lubricants
Second line: ocular antihistamines/mast cell stabilizers
Third line: oral antihistamine may be added; ocular decongestant/antihistamine
Referal
What are ocular antihistamine/mast cell stabilizers?
Ketotifen fumarate
Approved for children 3 +
Works within minutes
Side effects: headache, dry eyes, eye irritation, pain in eye, pharyngitis, rhinitis
What are topical decongestants?
Phenylephrine Naphazoline Oxymetazoline Tetrahydrozoline - Direct-acting agents - Constrict conjunctival blood vessels/reduce redness - Can cause rebound congestion
What are topical antihistamine or antihistamine/decongestant combination?
Pheneramine and antazoline
Combined with naphazoline
Adverse effects: stinging/burning on instillation, antichoinergic properties –> pupil dilation
What are the hallmarks, signs and symptoms of bacterial conjunctivitis?
Colored mucoid discharges
Diffuse redness, mucoid discharge, matter on lashes and lids, typically unilateral
Discomfort, greenish/yellowish discharge, eyes can be matted shut
Will require antibiotics
What are the hallmarks, signs and symptoms of viral conjunctivitis?
Redness –> “pink eye” with watery discharge
Diffuse redness
Discomfort, watery, photophobia, foreign body sensation
Usually clears on its own
What is corneal edema?
Occurs due to a variety of conditions: over wear of contact lenses, surgical damage to cornea, inherited corneal dystrophies
Hallmarks: halos or starbursts around light messing with vision (due to fluid accumulation)
What are treatments of corneal edema?
Goal: withdraw fluid from the cornea
Hyperosmotic agents
–> first line: sodium chloride solution (only hyperosmotic OTC product)
–> Augmented treatment: ointment
–> no improvement: switch to 5% solution
What if a foreign body gets into the eye?
Determine activity which resulted in injury
Self-treatment appropriate with minor irritations
Remove irritant by irrigating eye
Refer if not obvious
What are the causes and signs/symptoms of minor eye irritation?
Loose foreign body, contact lens wear, wind or sun exposure, smog, chemical fumes, chlorine
Eye redness and or pain or gritty sensation
What is the treatment for minor eye irritation?
Artificial tear solution
Nonmedicated ointment
Zinc sulfate drops
What are chemical burns due to and what does severity depends on?
Alkali: oven cleaners, cement, lye Acids: battery acid, vinegar Detergents Other: solvents/irritants Depends on agent and exposure time
Which chemical burns is most severe? Alkali, acids, detergents?
Alkali
Continue to dissolve cornea
Acids are neutralized rather quickly
What are the goal for chemical burns?
Neutralize pH
Irrigate immediately and continuously with sterile saline or tap water
Irrigation must be continued until seen by eye care provider
Characteristics of red eye surface?
Eye pain Blurred vision not associated with ointments Sensitivity to light History of contact lens wear FB with fragments Chemical exposure Eye exposure to heat No improvement after 72 hours
Characteristics of eye lid disorder?
Red thickened eyelids, scaling, Blunt trauma to the eye Exposure to chemicals Head lice No improvement after 72 hours
