Eye OTC - Dry-Eye Syndrome

Question 1

Define dry eye syndrome. (2)

Answer 1

Tear film disorder due to tear deficiency or excessive evaporation.

Causes ocular surface damage and associated with symptoms of discomfort.

Question 2

What factors can exacerbate dry eye syndrome? (4)

Answer 2

Dry air
Wind
Dust
Smoke

Question 3

Explain the pathogenesis of dry eye syndrome. (2)

Answer 3

Ocular surface, tear-secreting glands, Meibomian glands + lids function = secrete and clears tears.
Dysfunction in any component results in unstable and unrefreshed tear film.

Question 4

Explain tear composition. (1)

Answer 4

Complex mix of water, lipids, salts, muffins, immunoglobulin, antimicrobial proteins and growth factors.

Question 5

Explain the tear structure. (3)

Answer 5

Inner layer (mucin adheres to corneal epithelium)
Middle layer (aqueous/mucin phase)
Outer layer (lipids)

Question 6

How are tears produced? (2)

Answer 6

Lacrimal glands ocular surface epithelium + conjunctival goblet cells (secrete hydrated mucous gel of inner and middle layers)

Meibomian glands (made in outer lipid layer)

Question 7

What are the symptoms of dry eye syndrome? (6)

Answer 7

Bilateral
Sensations (foreign body, irritation, soreness)
Contact lenses poorly tolerated.
May not describe eyes as dry.
Vision changes due to loss of surface moisture.
Photophobia.

Question 8

What are the treatment options of dry eye syndrome? (2)

Answer 8

Hypromellose 0.3% eye drops:
- Use artificial tears at 30 minute intervals if severe symptoms.
- Reduce frequency when symptoms improve.
- Use preservative free preparations (> 6 applications/day) due to high risk of ocular irritation.

Lubricants:
- Eye ointment with paraffin/parrafin + lanolin (simple eye ointment/lacri-lube/lubri-tears)
- Useful at bedtime because it gives prolonged lubrication.
- Not for daytime use as it blurs vision.
- Remove contact lenses pre-administration.
- Contact lenses replaced in the morning.
- Contact lenses avoid during the day.