Ophthalmology: Operational Contact Lenses Flashcards
Corneal Anatomy
Remember: the cornea is avascular (O2 from the atmosphere, nutrients from tears)
Benefits of contact lenses
- Increased Field of View
- Decreased Abberations
- Increased Comfort
Cons of contact lenses
- More care
- More cost
- More risk
Not a TRICARE covered benefit unless in the aviation community
Contact lenses are supported within the ____ ____.
tear film
Note: tear quantity/quality effects lens performance
Types of contact lenses
- Rigid Gas Permeable (RBP aka GP)
- Soft (SCL)
What are GPs primarily used for?
Corneal irregularities (e.g., keratoconus)
Note: GPs provide superior optics for visual acuity, but are difficult to get used to
Characteristics of SCLs
- 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
Poor fit or extended wear of contacts can cause…
- Corneal Hypoxia
- Corneal Edema
- Corneal neovascularization
- Change in refractive error/power
- Increased risk of infection
CLs sit on the cornea, while glasses are ______ away from the corneal plane
12-13 mm (aka Vertex distance)
This is why contact prescriptions are NOT the same as glasses prescriptions
Fusarium Keratitis
80% of cases tied to poor compliance or bad hygienic practices
True/False
SNA applicants can be waived with uncorrected VA 20/400 if corrected to 20/20-0 with CLs
False
Used to be true, but no longer valid
Common Complications of CLs
Dry eye
Corneal neovascularization
Conjunctivitis
Sterile corneal infiltrate
Corneal Abrasion
Blepharitis
Corneal ulcer (microbial keratitis) = true emergency
Corneal ulcer aka Microbial Keratitis
Treatment = discontinue CL and 3rd/4th gen fluoroquinolone and cycloplegic drops (if unable to refer)
CLARE
Contact Lens Associated Red Eye
Treatment = d/c CL wear, prophylatic Abx until seen by Ophtho
Myopic spectacle lenses = ______ CL power
less
Hyperopic spectacle lenses = ______ CL power
more
CL solution used for operational needs
Multipurpose (all in one cleaner/disinfection)
Note: NOT the same as saline solution and cannot be used with hard lens
You should replace your CL cases every ______
3 months
True/False
Daily Wear (CL) is required for Aviation
True
Exception: operational requirement necessitates flex wear (need a day of rest – no CL wear – after EW)
Studies show _____ greater incidence of microbial keratitis with extended wear
10-15x
True/False
Most eye drops can be used with CLs
False
True/False
Members who wear CL must carry back-up spectacles during all flights and have CL wear notated on up-chit
True
3 Requirements for CL wear
- Must meet VA standard with contacts on
- Contact lens usage must be authorized on up-chit
- Must fly with back up specs
Telltale sign of wearing CL too often
Giant papillary conjunctivitis
“Every time I blink my contact moves around”
Treatment for Blepharitis
Wash with baby shampoo
Warm compress
do NOT wear CL until it resolves
Cells in anterior chamber are diagnostic of…
iritis/uveitis
What labs should you check if a pt presents w/ corneal arcus (senilis)
Lipid panel
Pinguecula vs Pterygium
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)
Most common type of CLs in Naval Aviation
Soft (SCL)
Silicone hydrogels that cover entire cornea
Treatment for CL wearer with negative fluorescein stain (NaFL) but underlying haze?
Think Sterile Corneal Infiltrate
Discontinue CL wear
Non-preserved artificial tears
+/- Abx (unable to refer or concerned for infection vs inflammation)
Can you use multipurpose solutions with extended wear CLs?
Yes
All in one cleaner/disinfectant (rub lenses 10-15s, put in case and fill with solution)
Pros to CL wear
Increased Field of View
Decreased Abberations
Increased Comfort
3 things needed to fly with CLs
- Must meet VA standard with contacts on
- CL usage authorized on upchit
- Must fly with back up specs
3 conditions caused by poorly fitted CLs
- Corneal Hypoxia
- Corneal Edema
- Corneal Neovascularization
Also causes change in refractive error/power and increased risk of infection
