Analyzing Intraocular Lenses Using Wavefront Technology
Intraocular lenses (IOLs), which are implanted in a patient’s eye to treat cataracts, ensure people continue to see well as they age by correcting vision and astigmatism (deformation of the cornea). This can only be achieved through a high-precision design of the lens surfaces.
For the analysis of IOLs, the relevant ISO standard 11979 defines the determination of optical characteristics, such as the measurement of effective focal length and the qualitative evaluation by means of the modulation transfer function (MTF). The additional evaluation of the wavefront across the entire aperture of the lens is particularly helpful when designing a new lens shape.
This analysis of intraocular lenses can now be achieved with the new WaveMaster® IOL 2 introduced by TRIOPTICS. Its functional principle is based on wavefront measurement with the use of a Shack-Hartmann sensor and permits the quality control of all conventional refractive intraocular lenses: monofocal, toric, spherical and aspheric. Measurements can be performed on hydrophobic and hydrophilic lenses in-air or in the in-situ eye model with optional heating per ISO 11979. Easy-to-use software permits the user-independent and fully automated determination of the refractive power, the cylinder power, MTF and deviation of the toric axis from the marked axis. “The refractive power of IOLs can be measured with accuracies of up to one-third of the tolerances stated in the ISO standard,” says developer Dr. Judith Krawinkel. “This helps us meet our customers’ quality requirements and support lens manufacturers in the development of new lens models.” For customized analyses of lens aberrations, particularly in research and development, the software can be expanded to include a Zernike analysis module.
The development of the WaveMaster® IOL 2 especially focused on the simplified und user-independent measurement of toric IOLs. This includes the automated determination of the MTF in both main sections. With the integration of an additional camera, the WaveMaster® IOL 2 automatically determines deviations of the markers on the lenses from the measured toric axis. The camera image can also be used for a visual inspection of the lenses.