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