SCL Fitting

Question 1

Steps in selecting a Lens

Answer 1

1. Decision on modality
2. O2 and water content considerations
3. Decision on material
4. Choose starting lens
5. Look at available Rx and cost
6. Manufactures guide for fitting

Question 2

Modality of wear considerations

Answer 2

Occasional (3 hours, 2/7)
- dailies

Work (9 hours, 5/7)
- monthlies

Full time wear at work, but non compliance
- dailies

Full time (16 hours, 6/7)
- fortnightly or monthlies

Slit lamp exam
- hypoxia
- previous pathology

Question 3

O2 and water content considerations

Answer 3

Water content
- if lenses drying up, increasing water content draws out water

Oxygen
- increased WT = Increased O2 transmission

Question 4

Decision on material

Answer 4

• hydrogel or silicone hydrogel
• Rx range
• cost

Question 5

How to figure out BOZR

Answer 5

• flattest K x 1.1
• fit slightly flatter than flattest k

Question 6

How to adjust Rx for BOZR

Answer 6

• K=F/(1-dF)

F= Rx
d= BVD in metres

Question 7

When to use a toric lens?

Answer 7

If cyl is >1.00

Question 8

Steps for inserting a SCL

Answer 8

• Px has head against the chair, Px looks up/down
• lower bottom lid, and Px looks away
• place lens onto conj,keep holding lids, Px looks left/right/up/down
• massage top lid if air bubbles

Question 9

How do you remove a SCL

Answer 9

• same eye lid control
• Px looks away
• slide SCL off cornea
• pinch off the conj
• perform health check

Question 10

What to record on record card for fitting

Answer 10

• coverage
• centration
• movement on blink
• comfort
• lag
• sag
• push up
• tightness

Question 11

Why does lens need to fit well

Answer 11

• comfort
• corneal coverage
• good centration
• movement on blink
• optimal tightness
• stable vision

Question 12

Characteristics of a steep fit

Answer 12

• minimal lens movement
• reduced limbal crossing
• conjunctival identification
• conjunctival redness
• vision improves immediately post blink

Question 13

Characteristics of a flat fit

Answer 13

• increased movement
• buckling at lens edge
• poor centration
• variable vision
• lens awareness