Optical Path Wavefront Analysis - Corneal Topography

The OPD-Scan III continues the tradition of being an excellent multifunctional ophthalmic device. It combines a corneal topographer, auto refractor, wavefront refractor, wavefront analyzer, internal optical path difference analyzer (OPD) and light/dark pupilometry.

This helps guide the proper IOL selection based on the spherical aberration correction of the IOL. This is important in working toward the goal of leaving the post-cataract surgery patient with as little total spherical aberration as possible.

A wavefront analyzer helps us understand the mysteries of refractions. In the past, all we had were topographers and auto refractors. On occasion, we see a patient whose vision doesn't significantly improve with refraction. The OPD-Scan III does a great job of presenting the higher-order aberrations in a multitude of displays.

Explaining higher-order aberrations to patients is easier with the OPD-Scan III, because it has the ability to show comparative images with and without higher- and/or lower-order aberration corrections.  This visual presentation greatly simplifies the discussion with patients, so more time can be spent on the discussion of treatment options.

As time marches on, more and more of cataract surgery patients are also post-refractive (LASIK) surgery patients. The alterations to the cornea present many problems to the surgeon. Many patients inform the surgeon that they've had previous LASIK surgery, but they have no documentation—many don't even know if they had a myopic or hyperopic correction. This is easily elucidated with corneal topography, but the IOL calculations can still be tricky. In order to obtain more accurate results, several different methods have been developed to help select the appropriate post-refractive IOL. The OPD-Scan III is able to calculate the effective central corneal power (ECCP) to provide a K-reading for IOL calculations.