Complete Data for Choosing IOLs

The OPD-Scan III collects and displays key data in minutes for fast, accurate decisions.

By Mitchell A. Jackson, MD

In addition to refraction, we evaluate several complex factors when selecting an IOL. The OPD-Scan III, which combines an autorefractor, keratometer, pupillometer, corneal topographer and wavefront aberrometer, has multiple maps that help me select the best IOL for my patients. When I look at the printout alongside the axial length from an IOLMaster (Zeiss) or Lenstar (Haag-Streit), I can choose the optimal lens in less than a minute. And the patient experience is so fast, they hardly have time to blink.

Help Selecting IOLs

To achieve the best outcomes, we must choose the most appropriate lens for each patient. All patients have high expectations for cataract surgery, and those who are spending their own money on premium IOLs will demand the best. The OPD-Scan III excels at supplying three key pieces of information that help me choose the best IOL:

Figure 1. The cataract is visible in this retro-illumination image.

Figure 2. This side-by-side comparison shows the axial map and visual acuity before and after implantation of a toric IOL.

Angle kappa. The eye image shows me the angle kappa in millimeters and degrees. If patients have high angle kappa (my cut-off is greater than 0.4 mm), then a multifocal IOL may induce more aberrations, glare and halo. In my opinion, patients with a higher angle kappa who want presbyopia correction should receive an aspheric Crystalens AO (Bausch + Lomb) or a monovision setup, including an astigmatic toric lens if they have astigmatism.

Pupil size. The OPD-Scan III displays mesopic and photopic pupil sizes, both of which are key when choosing a multifocal IOL. When I compare the enlarged pupil in dim illumination versus the contracted pupil in bright light, I know if I need a pupil-dependent multifocal lens such as the AcrySof IQ Restor (Alcon) or a non-pupil dependent lens like the Tecnis (AMO)—the Tecnis being more advantageous in low light situations.

Spherical aberration. The OPD-Scan III provides me with a picture of the total visual system, including the axial map, average pupil power and effective central corneal power. Furthermore, it‘s the only system that includes the spherical aberration of the cornea, which helps when I‘m performing cataract surgery on patients who have previously undergone LASIK surgery. I‘ve done about 30,000 LASIK procedures, and those patients often return for cataract removal.

Post-myopic LASIK patients usually have positive spherical aberration, and post-hyperopic LASIK patients usually have negative spherical aberration. By knowing the true amount of corneal spherical aberration (SA), I can choose the correct monofocal IOL (for example, the AMO Tecnis monofocal reduces SA by 0.27 µm and the Bausch + Lomb Akreos has an SA of 0) to reduce or eliminate any residual corneal aberration for these post-LASIK cases. The OPD-Scan III device also gives effective corneal power post-LASIK, useful for the various IOL formulas such as those found on the ASCRS website (iol.ascrs.org).

Toric IOL Advantages

The OPD-Scan III has a report called the Toric IOL Summary, which helps ensure that I achieve excellent outcomes with these lenses. Its features support accurate marking and alignment, which are extremely important with toric IOLs where just a 4° misalignment will cause a 14% loss in astigmatic effect and 10° will have a whopping 34% reduced effect.

Figure 3. Retro-illumination shows alignment markings of the toric IOL at 1-day postop, showing any small change in the position of the IOL without dilation.

Figure 4. Eyes with high angle kappa are not good candidates for multifocal lenses.

The toric IOL summary map lets me establish a landmark for the steep axis. We mark the patient while in a seated position to rule out cyclotorsion and let those marks guide us during surgery. For example, the OPD-Scan III lets me mark a blood vessel on the sclera. Not having to do extra marking at the time of surgery saves time and money with accurate placement of the toric IOL.

After cataract surgery, the features of the OPD-Scan III enhance my ability to evaluate surgical outcomes. The retro-illumination image shows toric IOL alignment markings at the 1-day postop visit, which allows me to see if there‘s been any small change in the position of the IOL without dilating the patient.

Patient Education

The OPD-Scan III also helps me set patients‘ expectations and show them what‘s going to be happening inside their eye. Its corneal summary map displays any corneal issues preoperatively, so I can show patients how aberrations on the cornea can impair their vision. My staff uses the retro-illumination feature to show patients and their families the cataract and illustrate how it looked several years ago, and how it has progressed to a condition that requires removal. After surgery, patients can see their new IOLs. If there‘s any lens shift, tilt or haze in the posterior capsule, they can see that, too.

Finally, the visual acuity map helps me show patients the true visual results of cataract and LASIK surgery. For patients with premium IOLs, I can compare their preop vision (with and without eyeglasses) to their post-surgery vision without glasses. That‘s pretty dramatic. When patients don‘t opt for the recommended premium IOL, the visual acuity map backs up the expectations that we‘ve set. Although we‘re very clear that these patients will still need glasses, they tend to compare their vision before surgery with glasses to their post-surgery vision without glasses. This map lets us compare apples to apples—without glasses before and after. From the very clinical side of cataract surgery to this very human side, the OPD-Scan III provides very clear, fast and welcome support. ■