OTHER LENS DESIGNS;
A. PIGGYBACK TYPES
1. Piggyback
Fit steep soft lens and then perform
over-K's and fit RGP lens based upon over-K's
Fit high Dk RGP
Benefits: Comfort & Centration
Problems: Steep enough soft lens, bubble
between soft & RGP, edema, care system
2. Soft Perm (Wesley-Jessen)
Combination RGP (styrene) and 25% soft
blanket
Preferable to piggyback
14.3mm OAD; 8.0mm RGP; 7.0mm OZD
Available as steep as 6.5mm BCR
Benefits same as piggyback
Problems: tight fit, difficult to remove
(tearing), edema
3. Flexlens (Paragon Vision)
Soft lens with circular cutout section
for an RGP lens to fit (see attached information)
Advantages & disadvantages same as
other designs
B. SPHERICAL DESIGNS
1. Rose K (Lens Dynamics)
Small lens design with 6.3-6.5mm OZD and
5-6 blended PC's designed mathematically; flat, standard and steep edge lift designs (flat
often preferable)
Typically provides good centration
Expensive $75 for warranted with 2
exchanges w/in 90 days.
Fitting information attached
Boston ES material
2. Soper Cone
Traditional design: one steep pc
Still used by many labs
3. Ni-Kone (Lancaster, PA)
"Tri-Base Curve" philosophy
for centration purposes
4. COMFORTKONE (Metro Optics)
Made to order ($60 warranted)
Fluoroperm 30 material