5 - Lacrimal System Evaluation (Exam 1) Flashcards
What does the lacrimal system do?
Produce, distribute, and drain the tear film
What is responsible for reflex secretion?
The lacrimal gland
What is the innermost layer of the tear film and what is it produced by?
Mucin layer
Conjunctival goblet cells, tarsal crypts of Henle
What is the middle layer of the tear film and what is it produced by?
Aqueous layer
Glands of Krause and Wolfring, lacrimal gland
What is the outermost layer of the tear film and what is it produced by?
Lipid layer
Meibomian glands, Glands of Zeis
Which layer of the tear film makes up the majority?
Aqueous (middle) layer
What 3 things would an aqueous layer deficiency result in?
- Dry, burning eyes
- Intolerance of dry air
- Mucous strands present in the eye
What would a mucin layer deficiency result in?
Dry, burning eyes
What would a lipid layer deficiency result in?
Dry, burning eyes
True lipid deficiency is very rare
What is often a cause of mild lipid deficiency?
Chronic blepharitis or meibomianitis
What are the 2 types of lid apposition?
Ectropion
Entropion
How does ectropion impact the distribution of tears?
Tears do not properly drain because inferior punctum does not contact tear lake
What is epiphora?
Excessive tears running down the cheeks
Often a result of ectropion or entropion
How does entropion impact the distribution of tears?
Lashes turn inward and result in reflex tearing
Overabundance of aqueous layer results in change in osmolarity and epiphora
What are 3 types of exposure disorders related to dry eye?
- Partial blinker
- Nocturnal lagophthalmos
- Exophthalmos
How are tear production disorders commonly treated?
Artificial tears
Punctal plugs
Restasis
How are tear distribution disorders commonly treated?
Surgical repair if lid apposition present
Lubricating ointments/taping lids shut during sleep
Treatment of underlying disease (hyperthyroid)
How are tear drainage disorders commonly treated?
Medical or surgical treatment
What are 3 types of tear drainage disorders?
- Epiphora (congenital or acquired)
- Canaliculitis
- Dacryocytitis
What is dacryocystitis?
Infection/ inflammation of the lacrimal sac
What are 5 important clinical evaluation procedures involving the lacrimal system?
- Observe lid position and puncta position
- Tear meniscus evaluation
- Vital dyes (fluorescein, rose bengal, etc.)
- Tear break up time
- Examine lids/lashes
What are 3 additional procedures used to supplement lacrimal system findings?
- Schirmer tests
- Jones dye tests
- TearLab
What is a normal tear break-up time?
10-15 seconds
What would a dry eye patient’s Schirmer test results show?
Less than 5 mm of tears after 5 minutes
