113 Wickham Tce Brisbane City Qld 4000
OptometrY & Advanced contact lenses
In contact lens design one of the most commonly used rules is that a change of BOZR of 0.1mm equates to a liquid lens power change of 0.5 dioptres. This is only technically true for lenses with back optic zone radii of 8.0-8.5mms. In fitting modern rigid gas permeable contact lenses, practitioners need to be aware that 0.1mm changes can sometimes require substantially more power compensation. This is often true for highly aspheric lens designs which require very steep radii to achieve adequate sagittal depth.
eg. in steepening a BOZR 5.00mm / 0.98e ICD miniscleral by 0.1mm, the practitioner must compensate the power by -1.38 dioptres.
© David Foresto 2018
The following are tools which we have made open for use by all Optometrists, Ophthalmologists,
students and laboratories.
- used to calculate the oxygen available to the cornea with variable miniscleral contact lens parameters.
Formula derived from "Predicting estimates of oxygen transmissibility for scleral lenses"
L.Michaud et al. Contact Lens & Anterior Eye 35 (2012) 266– 271