SCL fitting Flashcards
Steps in selecting a lens
- Decision on modality
- O2 & water content considerations
- Decision on material
- choose starting lens
- look at available Rx + cost
- Manufactures guide for fitting
- Modality of wear consideration
Occasional (3hrs, 2/7)
- dailies
Work (9hrs, 5/7)
- monthlies
F/T wear at work, but non compliance
- dailies
Full time (16hrs, 6/7)
- fortnightly / monthly
Slit lamp –> hypoxia/previous pathology
- O2 & H20 content considerations
O2
- increased WT = increased O2 transmission
H2O content
- if lens drying up = increasing H2O content draws out H2O
- Decision on material
- hydrogen/silicone hydrogel
- Rx range
- cost
- process of choosing starting lens
BOZR calc
- flattest K x 1.1
- fit slightly flatter than flattest K
Adjusting Rx for BOZR
- K=F/(1-dF)
- F=Rx d=BVD (in metres)
Use topic lenses when = cyl > 1.00D
Steps for inserting SCL
- px head against chair, facing up
- lower bottom lid, px looks away
- place lens onto conj, keep holdings lids, px looks left/right/up/down
- massage top lid if air bubbles
Steps for removing SCL
- same eyelid control
- px looks away
- slide SCL off cornea
- pinch off the conj
- perform health check
What to record for fitting
- coverage
- centration
- movement on blink
- comfort
- lag
- sag
- push up
- tightness
Why does lens need to fit well
- comfort
- corneal coverage
- good centration
- movement on blink
- optimal tightness
- stable vision
Characteristics of a steep fit vs flat fit
steep = minimal lens movement
flat = increased movement
steep = reduced gimbal crossing
flat = poor contraption
steep = vision improves immediately post blink
flat = variable vision
steep = conj identification + redness
flat = buckling at lens edge + lens awareness