Yes, because we are fitting Irregular Corneas with the UltraHealth lenses it is necessary to achieve full clearance under the Vault and Under the Inner Landing Zone. You may use an OCT instrument to measure the clearance as well.
Once you achieve the proper clearance in the vault; observe the Inner Landing Zone to determine skirt curve. Use flattest skirt possible that provides slight clearance in the Inner Landing Zone (ILZ) and that has no wrinkling at the skirt edge.
Once you have the correct fit – over-refract to find your final lens power. Once you have over-refracted one lens your over-refraction will be the same for each lens. Add the over-refraction to the power of the diagnostic lens you wish to order.