Ophthalmology: Operational Contact Lenses

Question 1

Corneal Anatomy

Answer 1

Remember: the cornea is avascular (O₂ from the atmosphere, nutrients from tears)

Question 2

Benefits of contact lenses

Answer 2

• Increased Field of View
• Decreased Abberations
• Increased Comfort

Question 3

Cons of contact lenses

Answer 3

• More care
• More cost
• More risk

Not a TRICARE covered benefit unless in the aviation community

Question 4

Contact lenses are supported within the ____ ____.

Answer 4

tear film

Note: tear quantity/quality effects lens performance

Question 5

Types of contact lenses

Answer 5

• Rigid Gas Permeable (RBP aka GP)
• Soft (SCL)

Question 6

What are GPs primarily used for?

Answer 6

Corneal irregularities (e.g., keratoconus)

Note: GPs provide superior optics for visual acuity, but are difficult to get used to

Question 7

Characteristics of SCLs

Answer 7

• Default for aviation
• Cover entire cornea (can be used as a bandage)
• Silicone
• Toric (astig) and Spherical options
• Extended vs Daily
• Vision may not be quite as good as with glasses or GPs

Question 8

Poor fit or extended wear of contacts can cause…

Answer 8

• Corneal Hypoxia
• Corneal Edema
• Corneal neovascularization
• Change in refractive error/power
• Increased risk of infection

Question 9

CLs sit on the cornea, while glasses are ______ away from the corneal plane

Answer 9

12-13 mm (aka Vertex distance)

This is why contact prescriptions are NOT the same as glasses prescriptions

Question 10

Answer 10

Fusarium Keratitis

80% of cases tied to poor compliance or bad hygienic practices

Question 11

True/False

SNA applicants can be waived with uncorrected VA 20/400 if corrected to 20/20-0 with CLs

Answer 11

False

Used to be true, but no longer valid

Question 12

Common Complications of CLs

Answer 12

Dry eye

Corneal neovascularization

Conjunctivitis

Sterile corneal infiltrate

Corneal Abrasion

Blepharitis

Corneal ulcer (microbial keratitis) = true emergency

Question 13

Answer 13

Corneal ulcer aka Microbial Keratitis

Treatment = discontinue CL and 3rd/4th gen fluoroquinolone and cycloplegic drops (if unable to refer)

Question 14

CLARE

Answer 14

Contact Lens Associated Red Eye

Treatment = d/c CL wear, prophylatic Abx until seen by Ophtho

Question 15

Myopic spectacle lenses = ______ CL power

Answer 15

less

Question 16

Hyperopic spectacle lenses = ______ CL power

Answer 16

more

Question 17

CL solution used for operational needs

Answer 17

Multipurpose (all in one cleaner/disinfection)

Note: NOT the same as saline solution and cannot be used with hard lens

Question 18

You should replace your CL cases every ______

Answer 18

3 months

Question 19

True/False

Daily Wear (CL) is required for Aviation

Answer 19

True

Exception: operational requirement necessitates flex wear (need a day of rest – no CL wear – after EW)

Question 20

Studies show _____ greater incidence of microbial keratitis with extended wear

Answer 20

10-15x

Question 21

True/False

Most eye drops can be used with CLs

Answer 21

False

Question 22

True/False

Members who wear CL must carry back-up spectacles during all flights and have CL wear notated on up-chit

Answer 22

True

Question 23

3 Requirements for CL wear

Answer 23

1. Must meet VA standard with contacts on
2. Contact lens usage must be authorized on up-chit
3. Must fly with back up specs

Question 24

Telltale sign of wearing CL too often

Answer 24

Giant papillary conjunctivitis

“Every time I blink my contact moves around”

Question 25

Treatment for Blepharitis

Answer 25

Wash with baby shampoo Warm compress do NOT wear CL until it resolves

Question 26

Cells in anterior chamber are diagnostic of...

Answer 26

iritis/uveitis

Question 27

What labs should you check if a pt presents w/ corneal arcus (senilis)

Answer 27

Lipid panel

Question 28

Pinguecula vs Pterygium

Answer 28

Pinguecula = yellowish patch/bump on the medial conjunctiva Pterygium = growth of fleshy tissue on the conjunctiva that extends over the cornea (often arising from a pinguecula)

Question 29

Most common type of CLs in Naval Aviation

Answer 29

Soft (SCL) *Silicone hydrogels that cover entire cornea*

Question 30

Treatment for CL wearer with **negative fluorescein stain (NaFL)** but **underlying haze**?

Answer 30

Think Sterile Corneal Infiltrate Discontinue CL wear Non-preserved artificial tears +/- Abx (unable to refer or concerned for infection vs inflammation)

Question 31

Can you use multipurpose solutions with extended wear CLs?

Answer 31

Yes *All in one cleaner/disinfectant (rub lenses 10-15s, put in case and fill with solution)*

Question 32

Pros to CL wear

Answer 32

Increased Field of View Decreased Abberations Increased Comfort

Question 33

3 things needed to fly with CLs

Answer 33

1. Must meet VA standard with contacts on 2. CL usage authorized on upchit 3. Must fly with back up specs

Question 34

3 conditions caused by poorly fitted CLs

Answer 34

1. Corneal Hypoxia 2. Corneal Edema 3. Corneal Neovascularization *Also causes change in refractive error/power and increased risk of infection*