TBUT

Question 0

.Symptoms of dry eye

Answer 0

1) Burning/stinging
2) Difficulty opening eyes in morning
3) Foreign body sensation
4) Dry/scratchy/gritty sensation
5) Photophobia / Blurry vision / Pain [if severe]
6) Excessive tearing

Question 1

.Purposes of tear film

Answer 1

1) Smooth optical surface
2) Lubrication to prevent lid from scraping cornea
3) Flushes away cellular debris / foreign matter
4) Supplies nutrients to avascular cornea
5) Contains antibacterial agents - Acts as eye’s first line of defense

Question 2

.Aspects of tear film evaluated when assessing dry eye

Answer 2

1) Thin, uneven tear meniscus [<10 sec]
4) Staining
5) Bubbles
6) Mucous/Oil

Question 3

.Factors, besides dry eye, that can reduce TBUT

Answer 3

1) Topical anesthetic
2) Exposure to preservative benzalkonium chloride (BAK)
3) Air movement (e.g. office w/ vents -> evaporation)
4) Forcibly holding lids during measurement

Question 4

.Differentiate staining vs. pooling on cornea

Answer 4

Rinse eye

Will remain if true stain

Question 5

.Sig of staining locations

Answer 5

Inferior

• Dry eye
• Staph blepharitis
• Nocturnal lagophthalmos

Superior
- Superior limbic keraroconjunctivitis (SLK)

Interpalpebral

• Dry eye - If cornea and conj stains
• CL - If only cornea stains

Pan-corneal

• Toxic
• CL

Pan-ocular
- Toxic

Question 6

.Where tear film is produced

Answer 6

Lipid layer

• Meibomian glands
• Glands of Moll - Glands of Zeis

Aqueous layer

• Lacrimal gland
• Glands of Krause - Glands of Wolfring

Mucin layer

• Goblet cells
• Crypts of Henle

Question 7

.Factors that can increase TBUT

Answer 7

1) Artificial tears

2) Decreased fluorescein conc

Question 8

.What sodium fluorescein stains

Answer 8

• Aqueous layer of tear film

- Interrupted areas in epithelium of cornea/conj