Week 2 - RGP Fitting 2 Flashcards
What 6 Points coincide with a good alignment fit?
• Good centration/constant pupil coverage
• No limbal crossing
• Adequate movement on blink, movement straight up and down
• Central - trace of fluorescein indicating minimal clearance
• Mid-periphery - band of touch
• Peripheral - adequate band of bright fluorescein
What 6 Points coincide with a Steep fit?
• Good centration/constant pupil coverage
• No limbal crossing
• Minimal movement on blink (even a very tight RGP usually shows some degree of movement). Or slow or limited recovery when lens moved.
• Central - bright area of pooling, can include air bubbles
• Mid-peripheral - wider band of touch
• Peripheral - narrow band of bright fluorescein
What 6 Points coincide with a Flat fit?
• Poor centration, can be in any direction depending on lids. Common
to see inferior decentration
• Limbal crossing
• Excessive movement on blink, often fast
• Central - area of touch (dark), the flatter the fit the smaller the area of touch
• Mid-Peripheral - not a clear band of touch as can merge with the central zone
• Peripheral - wide band of bright fluorescein, can include air bubbles
What is a lid attachment fit??
• Upper edge of the lens remains tucked under the top lid during blink so lens appears to sit slightly high
• This is acceptable especially in those who require a large TD or have a lower superior lid position
• Can actually be more comfortable when first fitting RGPs as there is no interaction between the top lid and edge of the lens
• This is acceptable as long as the pupil remains covered
• Fluorescein pattern assessment must still be done with the lens centred
What is the alignment with standard corneal lens and aspheric lenses?
• Alignment or the merest hint of apical clearance over the central
7.00 mm.
• Mid-peripheral alignment over about 1.50 mm.
• Edge clearance about 0.4 mm wide.
• Alignment or light touch over the central 5.00 mm.
• Mid-peripheral alignment.
• Narrow edge clearance just under 0.2 mm wide.
What does a flat fit and steep fit look like?
•Dense central area of dark blue touch surrounded by fluorescein edge of the lens.
•Area of touch is small with an indistinct as opposed to a sharply demarcated border.
• Fluorescein encroaches beneath the periphery of the central portion where
alignment would be expected with a correct fit.
• The fluorescein pattern gives central pooling.
• An air bubble is sometimes present with excessive central clearance.
• Heavy bearing is seen at the transition as an area of dark blue touch beyond the central pooling.
•The smaller the area of central pooling. the greater the degree of
steepness.
•The periphery gives only a thin annulus of fluorescein around the lens edge.
What
What are the grades for the CLEAR report define Edge Width?
• Edge width in the principal meridians
i +2 (>2 mm)
ii +1 (~1.5 mm band)
iii 0 (~1 mm band)
iv -1 (~0.5 mm band)
v -2 (no visible band)
