Ophthalmic nomograms are an evolutionary process that I have been studying over the past 10 years. What we do and what we measure today will be different than what we do and measure in the future. Surgeons used to argue over whether Shick or Gillette blades were the best for Radial Keratotomy. Now, we look at these RK blades from the early 1980’s and shudder at the thought of using them in the eye.

BRIEF BACKGROUND
Created by Svyatoslav Fyodorov, MD, of Moscow in 1981, one of the first ophthalmic nomogram was complex (Figure 1), but it provided the guidelines for future nomograms. Ten years later, Charles Casebeer, MD, developed one of the most organized nomogram systems up to that time. It worked almost like a recipe: any surgeon could use it to re-create a 4.2-mm optical zone and a -1.50 D correction in a 21-year-old eye. After he made the nomogram functionally available to the general ophthalmologist, Dr. Casebeer embarked on a series of lectures to teach ophthalmologists how to use it and standardize this refractive technique.

Figure 1. Dr. Fyodorov's RK Nomogram, circa 1981.

NOMOGRAMS IN REFRACTIVE SURGERY
When excimer lasers debuted in ophthalmology in the early 1990s, they held the promise of solving many of our patients’ refractive issues. Although these lasers certainly proved to be more predictable than RK at corneal modeling, we surgeons were flying blind without reliable nomograms for using them. Although companies provided “out of the box” treatments that had been tested through FDA trials, surgeons quickly found that outcomes varied based on technique, technology, and environment to mention only a few of the variables. Subsequently, Guy Kezirian, MD, Jack Holladay, MD, and I started discussing a Casebeer-type of excimer laser nomogram that would incorporate the patient’s age, the type of correction needed, and the type of laser system being used. We calculated our attempted versus achieved outcomes and began our formulations. The nomograms grew more complicated as we added variables such as LASIK versus PRK (with or without mitomycin C), significant amounts of preoperative cylinder, and how coupling affects the larger amounts of sphere.

Our nomograms continued to evolve. We learned that adding astigmatic incisions to eyes with RK incisions or preoperative sphere changed the overall outcome. Eventually, physicians such as Perry Binder, MD, Dr. Kezirian, and Dr. Holladay created software programs to help surgeons plan their outcomes. The Refractive Surgery Consultant software (Refractive Consulting Group, Inc., Paradise Valley, AZ), developed by Drs. Holladay and Kezirian was the first program to incorporate all surgical factors, such as the temperature and humidity of the OR; the patient’s sex, age, amount of astigmatism, and IOP; the type of excimer laser and the microkeratome or femtosecond laser used.

MEASURABLE VALUE
I had thought that my nomogram was pretty solid. After I began using the Refractive Surgery Consultant software, however, I got a call from Dr. Kezirian telling me that humidity was significantly affecting my outcomes. I was confused because my OR had humidity control, but when I watched some of my surgical videos, I realized that I was wiping the corneal bed of myopic but not of hyperopic patients. That small difference was enough to change my outcomes, and it registered as a humidity factor on the nomogram.

As Drs. Kezirian and Holladay incorporated progression formulas and attempted versus achieved R-squared values, surgeons’ R-squared values have improved. We have been able to fine-tune the treatment patterns achieved. I think nomograms are directly responsible for reducing refractive surgical enhancement rates from 5% to 10% a few years ago, to now less than 1% on a consistent basis.

DataLink
DataLink software was designed to take advantage of portable digital assistants (PDAs) or computers in nomogram outcomes analysis. Some time ago, I told Dr. Kezirian that as a refractive surgeon, I would appreciate having my Refractive Surgery Consultant nomograms available on my PDA. Instead of entering my data at the beginning of a preoperative examination and then leaving it alone, I wanted to be able to use an application to enter an eye’s calculations to my PDA and have the device produce a nomogram for that eye prior to surgery.

Dr. Kezirian created a Web-based software program called DataLink with a PDA application that works off the same servers. Thus, users are able to access their data from any Internet connection. DataLink includes nomograms for the WaveLight ALLEGRETTO Wave Eye-Q excimer laser (Alcon Laboratories, Inc., Fort Worth, TX) as well as other lasers, and it looks at how the lasers perform individually. It is also now incorporating data about intraocular lenses such as the Crystalens. The DataLink database now has approximately 400,000 eyes total.

What I appreciate most about the DataLink software is that it tells me exactly how I am performing surgically. For instance, I may look at a specific data set and see that the global rate of DataLink users achieving 20/20 refractive outcomes is 83%, and my personal rate is 99% (Figure 2). However, I may also see that anoter data set may not be performing as well as the international average. It gives me the input to say that I need to look at that data to see what I am doing and what can I do to make it better. I also like that I can look at certain trends compared with other surgeons, such as the duration of my surgeries and the techniques I use. Furthermore, the software estimates a patient’s gain or loss of vision. For example, if a patient asks me his likelihood of seeing 20/15, I can tell him that he sees 20/20 now and has approximately a 33% chance of gaining one line of vision from treatment with the WaveLight ALLEGRETTO Eye Q laser in my hands.

Figure 2. Dr. Stonecipher's DataLink profile.

CONCLUSION
When we talk about improving outcomes, we have to look at what really matters. I think the most important component in corneal refractive surgery is manifest refraction. If patients have an unhealthy ocular surface because of dry eye syndrome or a contact lens warpage, their manifest refraction data will be compromised, and I will not be able to get a good outcome. Second, we must determine the location of cylinder—lenticular versus corneal—because this knowledge will affect any customized or wavefront-optimized treatments.

We have to put good data in to get good data out. To that end, I employ a quality assurance technician who is in charge of confirming every refraction, which we take on every patient (even the happy ones). We conduct these nomogram visits at 1 month for myopes and 3 months for hyperopes, regardless of whether I performed LASIK or PRK. It is best not to schedule nomogram visits for later than 3 months, or the happy patients may not come back. These visits include a complete examination and refraction. It cannot be an automated refraction, and the same person must perform the test in the same way each time to control for variability.

These measures have helped me gather excellent data for my nomograms. When it comes to data collection, to borrow the Nike slogan, I strongly suggest that all surgeons “Just do it.”

Karl G. Stonecipher, MD, is the director of refractive surgery at TLC in Greensboro, North Carolina. He is a consultant to Alcon Laboratories, Inc., for the WaveLight ALLEGRETTO laser. Dr. Stonecipher may be reached at (336) 288-8523; stonenc@aol.com.

Guy M. Kezirian, MD, FACS, is a board-certified ophthalmologist. He is President of SurgiVision Consultants, Inc., an ophthalmic consulting company in Thousand Oaks, California, and a partner in Refractive Consulting Group, Inc. Dr. Kezirian may be reached at (805) 493-4200; guy1000@surgivision.biz.

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Last month, I addressed several common reasons surgeons fail to build a vibrant, sustainable optometric referral network. This month, let’s talk about methods that will help you succeed.

Become their surgical partner.
Create a monthly blog, e-mail, or fax blast (be sensitive to the technological sophistication of these practices) on a pertinent topic that you send to your referral network. Subjects might include an article you wrote, a lecture you gave, or a challenging case that generated interest on the message boards that you think the ODs would find interesting. You only need one topic per month. Distribute this resource every month so that you become their go-to MD for clinical direction and questions.

Help them become refractive surgery advocates.
Provide “lane cards” with treatment indications for LASIK, advanced surface ablation, and Lifestyle lenses. Refractive surgery is only one of many treatment options on which optometrists must be experts, and you want a way to help them at the very moment they are in the lane with a patient. They don’t remember treatment indications. They don’t always remember contraindications. Lane cards help you become the OD’s best friend in a dark room.

Host a “Look Inside” event.
Invite ODs into your office to actually experience the consultation process and the surgery-day process, and allow them to examine postoperative patients in person through the slit lamp. Include LASIK, surface ablation, and lens implant patients so they understand the full scope of possible outcomes and complications. This “look inside” is particularly useful for newer ODs who are often working in chain or discount eye centers and don’t yet have a wealth of surgical experience. These practitioners are often the best source for new referrals, because they are not yet aligned with an MD resource and their patients are less likely to be wedded to glasses.

Host a “Complicated Cases” dinner.
Invite three to four ODs to have dinner with you and discuss recent interesting cases. No presentations—just straight talk between vision professionals. Describe a few cases that showcase your expertise, and invite the optometrists to bring cases they have questions about (they do not need to be LASIK related). Sharing cases is a way to give ODs access to your surgical experience in a collaborative environment.

Create a relaxed climate for interaction.
Just as you hope to set your practice apart from others in the minds of patients, you need to do the same with referring optometrists. Over the years, these practitioners have been offered a million lunches with you or your OD liaison. They’ve been invited to look-alike CME dinner programs with guest speakers. But, are these efforts unique? Do they set you apart from other physicians? Instead, host events that showcase how inviting your practice is, how capable you are, and how attentively you and your team care for patients. It is critical that referring practitioners see your office to understand your unique patient experience.

Also consider hosting local entertainment events or charity golf scrambles to build relationships with local optometrists. Select a series of three to four scrambles within your community and invite three ODs to join you at each one. These 5 hours together create relaxed interaction and strengthen these individuals’ confidence in you as a person and a surgeon.

The key to building a successful, sustainable referral network is mutual respect, collaboration, and communication. Consider new ways to stand out from the pack.

Kay Coulson is founder of Elective Medical Marketing (www.electivemed.com), a consulting firm based in Boulder, CO that helps physicians build their elective vision service lines. Sign up for her monthly LASIK and Lifestyle IOL Growth Tips, or reach her at kay@electivemed.com.

This article reflects the views of the author. It does not necessarily reflect the opinions of Alcon Laboratories, Inc.

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