Incorporating toric lenses into your practice

With careful evaluation and management, these IOLs are sure patient pleasers.

By Elizabeth Yeu, MD

For surgeons who want to venture into or increase the percentage of premium IOLs in their practice, toric IOLs are a great place to start. For one thing, they provide a huge sales opportunity. Although toric IOLs represent the fastest growing segment of the premium IOL market, the penetration rate is still low compared to their potential; nearly 40% of the population has more than 1.0 D of astigmatism (Figure 1).¹

Figure 1. Based on the distribution in the U.S. population, astigmatism management is critical for success in refractive cataract surgery. About 37.5% of patients have >1.0 D of corneal astigmatism.

In my experience, patients who are well selected to receive toric IOLs are among the happiest patients postoperatively. These patients, likely lifelong dependents on vision correction — with many never having enjoyed great vision despite that correction — are now doing so without contacts or spectacles. Giving them the quality of vision afforded by toric IOLs can be a significant practice driver. Here are my tips for making toric lenses just that.

HAVE A PLAN

Evaluating their astigmatism

Initially, I recommend increasing the use of toric IOLs in the easiest-to-treat group: those with regular, stable astigmatism, average axial length (22-25.5 mm), who possess healthy corneas and retinas. Avoid patients with very low (<1.0 D) or very high (>3.0 D) astigmatism and anyone with poor zonular or capsular support.

I adjust my approach depending on whether the patient has with-the-rule (WTR) or against-the-rule (ATR) astigmatism. I prefer a toric IOL for >0.75 D ATR astigmatism or ≥1.50 D WTR astigmatism on anterior corneal topography. These “normal” eyes represent the best chance for predictable outcomes. Below those thresholds I offer laser arcuate incisions. Patients with low WTR astigmatism, in particular, can be successfully corrected with manual cataract surgery with limbal relaxing incisions (LRI); those with ATR are more sensitive to small amounts of residual error.

If cost is an issue or the patient wants a multifocal IOL, I will offer incisional astigmatism correction upwards of 1.50 D. Beyond that, I don’t feel that LRIs are sufficiently accurate, and I counsel patients that they may require a refractive enhancement postoperatively. I tell patients they have about a 70%-75% chance of achieving their desired uncorrected visual acuity with LRIs, compared to 90%-92% accuracy for toric IOLs.

I also adjust my astigmatic target based on age. We know that astigmatism changes over time, with a drift towards ATR. In a 55 year old, I target a postoperative outcome of 0.25 D WTR, while I would aim for an astigmatically neutral result in a 75 year old.

Preoperative protocols

Once you have a general toric IOL plan established, it is essential to manage factors that can affect the visual outcome, such as surgically induced astigmatism (SIA) or ocular surface disease.

In our practice, we test tear osmolarity and/or inflammatory tear markers in all refractive cataract patients. When those tests are positive, especially if there is also ocular surface staining, I start a short course of therapy before obtaining final biometry measurements. Ocular surface problems can significantly degrade the accuracy of preoperative measurements and severely impact refractive outcomes. Therapies are expanding, and I tailor their treatment based on disease severity and etiology, and may include non-preserved artificial lubrication, topical steroids of varying strength and formulations, a change (even if temporary) to preservative-free and oral glaucoma agents, and/or a self-retaining cryopreserved amniotic membrane.

In selecting the cylinder power and axis, it is important to look at the quality of the placido disk images and be sure that at least two preoperative keratometry measures are in agreement. We use at least two different analyzers to better understand the patients’ total corneal astigmatism. Corneas with dry eye or some other epithelial pathology or ectasia are the most likely to have wide variations in measurement (Figure 2).

Figure 2. Before (top) and after (bottom) Salzmann's nodular degeneration removal with a superficial keratectomy of the left eye. In the first topography, notice the higher levels of astigmatism with flattened and skewed placido rings nasally, due to the nodular degeneration. Topography image after the superficial keratectomy demonstrates a large reduction in astigmatism from 3.38 D to 0.86 D of WTR astigmatism. The placido rings appear much more regular throughout in the second topography. This example demonstrates the importance of management of epithelial-based disease before cataract surgery.

Also, you may want to use a “fudge factor” that takes into account the average contribution of posterior corneal astigmatism. We know that anterior corneal topography measurements tend to slightly underestimate total corneal ATR and to overestimate WTR.^2,3 Finally, in selecting a toric IOL for the second-eye surgery, have a good manifest refraction for the first eye to know if that eye responded in any surprising fashion.

CHOOSE YOUR TOOLS

Take advantage of new technologies, lenses

The toric IOL market segment is growing because we have better IOL technology, better diagnostic measurement devices and new laser options in cataract surgery that all contribute to precision and predictability. Both one-piece toric IOLs in the marketplace offer accurate and reliable toricity correction. For my younger patients I do prefer the IOL with the non-tinted optic as it provides superb contrast sensitivity.

One very important surgical pearl to ensure that your IOL stays in the intended steep meridian is to tap down on the optic at least once to ensure alignment has occurred. After tapping the optic down with the I/A handpiece, I stromally hydrate my surgical paracentesis before removing the co-axial I/A handpiece. If anterior chamber shallowing does occur, the optic has likely lost contact with the posterior capsule, and I will re-tap the optic down to promote contact with the posterior capsule at the very end of the case when the chamber is formed and stable.

SET UP YOUR PRACTICE FOR SUCCESS

The customer service angle

In addition to the clinical elements of success, it is important to set up your practice to generate interest in toric IOLs among patients. So put yourself and your staff in the right frame of mind for refractive cataract surgery, and provide a top-notch patient experience, while managing expectations. Our practice holds training seminars inhouse with experts from the Ritz Carlton Leadership Center; we have benefited from its precepts for customer service and employee engagement.

We tell patients to expect to spend two to four hours at our office for the cataract evaluation, as we do all measurements in one day. Our concierge specialist greets patients (Figure 3) and offers them beverages. Another employee escorts them from one station to the next; it is this person’s job to move people around efficiently.

Figure 3. At Virginia Eye Consultants, the Ritz Carlton approach to customer service helps patients feel welcome and relaxed.

After measurements are taken, patients meet with a cataract/refractive surgery counselor who talks to them about lifestyle, interests and surgical options, costs and financing. The counselors know my preferences and steers the conversation towards what they anticipate I will recommend based on preoperative measurements. We present premium lens options and laser cataract surgery to every patient, regardless of perceived ability to pay, except for those patients with comorbidities that would significantly limit visual potential.

The counselor attaches a half-sheet of paper to the chart with key information: K readings from the various devices, brief history, occupation/hobbies and any stated preferences (for example, wants to play golf without glasses). Patients watch an educational video while dilating, so by the time I see them for the exam, I have the information I need to make a decision and they are prepared to be receptive to my recommendations for greater spectacle independence, if appropriate.

Get in the right mindset

I recently made a helpful scheduling change. I used to see cataract consults throughout the week, mixed in with the corneal and intraocular pathology cases that comprise a significant part of our practice. But, it can be hard to switch gears from tertiary-level ocular pathology to refractive cataract surgery. I now have my cataract evaluations on Mondays and Thursdays. On those days, I can stay in the “zone” of refractive cataract surgery and give each patient the focus he or she needs. Those two days are less stressful and it has increased my adoption rate for laser cataract and premium IOLs, from 35%-40% previously to 50%-60%.

Conclusion

We have excellent options for astigmatism management, allowing us to offer more patients the chance for spectacle independence. With good patient selection and education, a strong emphasis on the patient experience and careful preoperative planning, it is possible to build a toric IOL practice with excellent outcomes and high rates of patient satisfaction. OM

REFERENCES

About the Author
	Dr. Yeu is assistant professor of ophthalmology at Eastern Virginia Medical School and in private practice at Virginia Eye Consultants in Norfolk, Va. Contact her at 757-622-2200 or eyeu@vec2020.com. Disclosure: Dr.Yeu has financial relationships with Alcon, AMO, Bausch + Lomb.