Experience a Paradigm Shift With The Marco 3-D Wave™
Understand how this device helped streamline patient scheduling and improve patient flow.
By Jonathan D. Solomon, MD
When I completed my training in ophthalmology, the idea of premium IOLs or refractive cataract surgery was just beginning to take hold. Like many of my colleagues, I saw this as an opportunity to develop a niche for my practice. Arming myself with the appropriate tools, a reproducible surgical technique and the ability to recognize good candidates, I decided to expand my practice.
The first thing I learned was that premium IOL patients require a considerable amount of chair time. In the beginning, I compiled core measurements with several instruments, and as a result, efficiency and patient flow suffered. I rearranged the way I scheduled patients to allow more face-to-face time, but it was still necessary for cataract patients to encounter nearly every device in the office. I solved this time-constraint issue when I purchased the Marco 3-D Wave. The 3-D Wave is a combination autorefractor, keratometer, pupillometer, corneal topographer and wavefront aberrometer all in one.
In this article, I'll discuss how the Marco 3-D Wave works, how it improved practice efficiency and patient scheduling, and led to a paradigm shift in my approach to patient care.
Ins and Outs of the 3-D Wave
With the use of an infrared slit beam and photodetectors situated on a rotating wheel, the 3-D Wave moves an incident beam along a specific pupillary meridian while a reflected beam returns in the same or opposite direction.
The instrument detects the time it takes for light to peak at the photodiode and calculates the optical pathway difference (OPD). Combined with software intended to measure photopic and mesopic pupil size, the 3-D Wave enables a single user to quickly and precisely gather the refraction across different pupil diameters. The device creates a wavefront profile by compiling 1,440 individual data points in only 0.4 seconds. It also displays higher-order aberrations to the 8th order across pupils between 2 mm and 6 mm in diameter.
The 3-D Wave is considered an objective, serially automated version of the handheld retinoscope and is the only wavefront sensor using dynamic skiascopy. In addition, it further refines data collection by highlighting spherical aberration and separating corneal measurements from the total ocular spherical aberration. The 3-D Wave compiles data in a clear and concise format and offers superior map presentations.
Improved Practice Efficiency
Because the 3-D Wave provides so much information so quickly, it has reduced the time it takes to acquire patient data by 30% and cataract patient consultations by 15 minutes in my practice. I'm able to see more patients and have more meaningful discussions with them about lifestyle issues, the anatomy of the eye and which lens is most appropriate. Once I consider all of the patient information and the data from the 3-D Wave, I usually can whittle down lens selection to two choices very quickly.
What's more, since the 3-D Wave combines five instruments in one, all of the tests are performed in a small space in one room. I no longer have to shuffle patients from one exam room to the next for diagnostic testing. Another bonus: The efficiency of the 3-D Wave enabled me to switch to blocked scheduling for cataract patient consultations. I schedule these patients back to back instead of scattering them throughout the day whenever scheduling permits, which improves patient flow.
The improvement in patient scheduling and the rapid collection of information the 3-D Wave provides has caused a very positive paradigm shift in my practice. No longer do I look at cataract patients as either individuals who pay out of pocket for premium multifocal IOLs or those who rely on medical insurance to pay for monofocal IOLs. I consider every patient a premium patient who deserves premium eye care. All patients benefit from the 3-D Wave technology, because they receive the best lens choice for them.
For instance, a 58-year-old nurse practitioner presented with bilateral posterior subcapsular cataracts and was interested in obtaining a full range of vision. The 3-D Wave enabled me to quickly review the topography and corneal spherical aberration and recognize the patient had a 6.98-mm mesopic pupil. She was concerned about the possibility of excess glare while driving at night but wanted to use the computer and read charts without her eye-glasses. She reported a great deal of difficulty wearing a trial pair of monovision contact lenses in her early 30s. After much discussion, we decided to choose the partially diffractive optic Aspheric ReSTOR D1 (Alcon Laboratories Inc.) implant (Figure 1). Following implantation in her nondominant eye, the uncorrected distance visual acuity was 20/20+; the uncorrected intermediate visual acuity was 20/25; and the uncorrected near visual acuity was 20/16 at 1 week. Three weeks after bilateral implantation, the patient reported minimal halos at night and total spectacle independence.
Figure 1. This image shows a 3-D Wave scan 2 weeks after implantation of the Aspheric ReSTOR D1 lens. Notice the mesopic pupil size and value of the corneal spherical aberration of 0.282 μm and the ocular spherical aberration of 0.069 μm, consistent with the intended reduction of -.20 of the AcrySof Aspheric platform.
Keratometrically Challenged Patients
The 3-D Wave is also helpful for those I call the keratometrically challenged — patients who've undergone LASIK, PRK or RK and those who have large degrees of corneal astigmatism. A single scan can differentiate between keratometric and lenticular astigmatism on the internal OPD map and total OPD map. I can cross-reference this with the wavefront refraction and verify higher-order aberrations. The refractive map can provide information about the peripheral cornea for patients who can't remember if they were nearsighted or farsighted before LASIK surgery. The Q values explain whether the cornea is prolate (negative Q-hyperopic LASIK) or oblate (positive Q-myopic LASIK).
Corneal Shape and Higher-order Aberrations
More than 10 million Americans have undergone keratorefractive surgery, and in their lifetime, all will develop cataracts. Aside from the challenge of calculating precise lens power, it's important to consider the effect corneal shape has on higher-order aberrations.
Current research has demonstrated that an optical system improves the closer it is to zero spherical aberration. Aspheric IOLs are designed to mitigate the naturally occurring positive spherical aberration of the corneal surface. Eliminating spherical aberration leads to improved contrast sensitivity during simulated night driving. The Tecnis Z9000 IOL (Abbott Medical Optics) and the AcrySof IQ SA60AT (Alcon Laboratories Inc.) are intended to induce negative spherical aberration. The SofPort LI61AOV IOL (Bausch & Lomb) is a neutral, zero aspheric lens that doesn't add or subtract spherical aberration. The question is how do you determine which IOL is the best choice?
For example, hyperopic LASIK tends to induce negative spherical aberration. A negative aspheric lens would further increase total ocular asphericity. Most would assume that a traditional monofocal IOL with positive spherical aberration would be the best lens choice, unless you measure the amount of spherical aberration before cataract surgery. This was the case concerning a patient who presented 4 years after hyperopic LASIK with a cataract in her nondominant eye, following measurable regression. Preoperatively, the 3-D Wave showed her eye had minimal, corneal spherical aberration. Therefore, I implanted the Bausch & Lomb LI61AOV to achieve the status of no spherical aberration.
Comparing Predictive Values to Post-op Results
With this example in mind, I conducted a pilot study that compared the postoperative total spherical aberration with the predicted value in the preoperative cornea in patients implanted with the Bausch & Lomb LI61AOV zero spherical aberration lens. Results showed that the total ocular spherical aberration was consistent with the inherent corneal spherical aberration. The follow-up feasibility study separated patients based on the preoperative corneal spherical aberration. Eyes with greater than 0.235 μm of spherical aberration received the Tecnis Z9000 IOL. Eyes with less than 0.1 μm received the Bausch & Lomb LI61AOV lens, while eyes between 0.1 μm and 0.235 μm received the AcrySof IQ SA60AT. With a goal of emmetropia, the desire was to nearly eliminate ocular spherical aberration. Most impressive was the power of the study's predictive value. The mean absolute error was 0.025 μm. With a well-centered IOL, the accurately measured corneal spherical aberration is combined with the correct aspheric lens, leading to a consistent reduction of higher-order aberrations.
Importance of Calculating Spherical Aberration
The vast majority of the nearly 3 million cataract surgeries performed annually involve the use of monofocal lenses, so we should always aim to precisely calculate and manage spherical aberration. The benefit of maintaining a tight control on spherical aberration is unmistakable, particularly when dealing with a population that can benefit from this the most. The 3-D Wave allows for the rapid collection of data that's necessary to achieve a high level of precision. In addition, appreciation of higher-order aberrations is quickly becoming the standard of care, and scrutiny of spherical aberration is another way to improve your patients' quality of vision and quality of life. OM
Dr. Solomon is in private practice in the Greater Washington, DC area. He's a clinical instructor at The Wilmer Eye Institute at The Johns Hopkins University. He also serves as chief of ophthalmology at the Dimensions Surgical Center in Bowie, Md.