Biok, Special Keratoconus rigid gas permeable contact lenses, having multi-curve geometry with soft junctions and a bevel zone, designed using digital technology with nanometer precision allowing the creation of very complex designs. BioK is a lens that perfectly meets the expectations of users in terms of stability, ease of fit and comfort for the wearer.
Start with :
Choice of lens diameter (ØT)
The diameter of the first trial lens is limited to that offered in the trial box (8 to 9.60), unless you order a custom-made trial lens, in which case the choice of diameter will depend on:
- Pointed center ⇒ Small ØT
- Oval: standard ØT
- Extended: large ØT
Choice of radius of curvature (r0)
The choice of r0 for the first trial lens depends on the corneal keratometry : r0 = K + 0.1:
Evaluation of fit
After fitting the trial lens, wait 30 minutes before proceeding to the fit assessment
A fit assessment always begins with an observation of the central zone
1 – Central zone (Static observation, lens centered)
Possible solutions : Try a flatter radius
Possible solutions : Try a tighter radius
2 – Centering and mobility
The evaluation of centering, mobility and periphery should only be done after finding the r0 which gives the best alignment in the center.
Centering (static observation)
The lens must be centered, a shift lower is tolerable as long as the lens does not cross the limbus.
Mobility (dynamic observation)
The lens should exhibit slight movement after blinking, with the lens moving up, then slowly refocusing.
3 – Periphery
BioK trial lenses have a standard peripheral clearance (d). Depending on observations it can be adjusted by ordering a tighter or flatter clearance.