Dry Eye Disease & Advanced-Technology IOLs

Preoperative dry eye testing pays off in happy patients.

By Kevin L. Waltz, OD, MD, and Brenda J. Wahl, OD

Advanced-technology IOLs were implanted in approximately one of every seven cataract surgeries in the United States in 2010. With dry eye disease common in the cataract surgery population, it is likely that many patients who elect to have advanced-technology IOLs also have dry eye disease. In our practice, for many years we have been screening preoperatively for pre-existing corneal astigmatism with corneal topography to help us determine candidacy for toric IOLs and presbyopia-correcting IOLs. In the last several years of screening topographically, we discovered it is common for our preoperative cataract patients to have undiagnosed and untreated dry eye. This was quite a surprise to us. It has changed our preoperative and postoperative routine in a meaningful way. In this article, we will explain our comprehensive approach to dealing with dry eye in our cataract surgery patients.

Initiating Preoperative Treatment

We discovered that approximately one out of every six of our patients presenting for cataract surgery has previously undiagnosed dry eye disease. These patients do not have a diagnosis of dry eye disease. They don't currently use, nor have ever used, artificial tears. We made the presumptive diagnosis of dry eye disease based on the patients' abnormal topography.

We began by initiating treatment with artificial tears four times per day and repeated the topography approximately one month later. The patients' topographies almost always improved with artificial tear therapy. The patients' topographies showed less overall irregularity and more regular bowtie astigmatism after a month of artificial tears. Just as importantly, as the topography improves the patient commonly reports improved vision on dry eye therapy alone, even in the presence of cataracts.

The improvement in the appearance of the topographical maps was striking. We have found this to be a valuable educational tool. Comparing the preop map with the post-dry eye therapy map in the presence of the patient really helps the patients' understanding of the process. Their being able to visualize the change in the map and subsequently correlate this with the improvement in their vision helps them to understand their condition and improves compliance with dry eye therapy.

Removing Patients' Doubts

Treating patients' dry eye disease preoperatively is valuable in many ways. The patients learn that they have dry eye disease and that artificial tear treatment is a useful therapy for their disease. This virtually eliminates the common perception among these patients that cataract surgery caused their dry eye disease.

Steroids are an effective treatment for dry eye disease. Previously, we would routinely treat all postoperative cataract patients with topical steroids. After about one month, we would stop the steroids. It should have been no surprise when some of our patients developed symptomatic dry eye during their postoperative course. Essentially, the postoperative steroids we prescribed were effective in routinely, incidentally treating any pre-existing, undiagnosed dry eye during the limited course of therapy. The temporary therapy would unwittingly improve the patient's dry eye disease. The patient would then complain of typical dry eye symptoms and would require artificial tear therapy to treat the dry eye disease. By diagnosing the dry eye problem preoperatively and initiating therapy, we have avoided the patient's incorrect perception that our cataract surgery caused the dry eye disease. This has been an important benefit to the patient and to us.

Preoperative Treatment and Torics

Accurate selection and placement of toric IOLs depends on accurate preoperative assessment. Dry eye disease can cause irregular astigmatism. Prior to using our current preoperative approach, we would occasionally implant toric IOLs and have suboptimal postoperative results due to a shifted axis of corneal astigmatism.

In retrospect, one of the issues in those patients was likely the unintended consequence of treating the patient's dry eyes with topical steroids postoperatively. We were not recognizing that the patient had dry eyes, but, again, we were treating the dry eyes postoperatively with the steroids. Treating the dry eye shifted the axis and the amount of corneal astigmatism in an unpredictable fashion. Our toric lenses would then be less effective. We would spend time and energy evaluating the patient to determine the cause of the problem and attempt to fix it. This wasted our time and the patient's time. By having a high index of suspicion for dry eye disease causing abnormal corneal topography, we have been able to reduce the number of refractive surprises while implanting toric IOLs.

Case 1. This is an elderly female who presented for cataract surgery. She had severe abnormalities of her corneal topography on initial exam (top). She was placed on artificial tears four times per day for five weeks and re-evaluated. Her subsequent corneal topography (bottom) demonstrated less irregularity in her astigmatism. The amount of astigmatism, as reported by the topographer, decreased 0.9 D and the axis shifted by 11 degrees. Clearly, these changes would have a profound impact on any consideration for a toric IOL. Also note how much her simulated corneal image improved with dry eye treatment.

Case 2. This is a 55-year-old female seeking a presbyopia-correcting IOL. She is a long-term contact lens wearer. Initial topography (top) demonstrates an inferior groove from her contacts as well as several areas of irregularity consistent with her dry eyes. We treated her dry eyes with artificial tears and asked her to discontinue her contact lenses. The subsequent topography (bottom) demonstrates a resolution of the inferior groove, a decrease in the irregularity and a less irregular astigmatism. The patient had successful multifocal IOL implantation shortly after the second topography.

Benefits With PC IOLs

Presbyopia-correcting IOLs are notoriously sensitive to refractive errors. Accurately measuring the astigmatism preoperatively to allow for an effective surgical plan is critical to success. We have used corneal topography to screen potential presbyopia-correcting IOL patients for years. We would commonly follow the patient with serial corneal topographies for corneal stabilization after discontinuing contact lenses.

The topographers we used were very effective at confirming when a patient's cornea was stable. We upgraded our topographer to the Zeiss Atlas 9000 in the fall of 2008 to provide an accurate determination of corneal wavefront, especially spherical aberration. We discovered the Atlas 9000 has superior resolution of topographic detail. This allowed us to identify changes in the serial topographies. We subsequently associated these topographic changes with untreated dry eye disease. Treating dry eye disease in our presbyopia-correcting IOL patients has probably decreased our enhancement rate. It has definitely allowed us to counsel the patient better about their expected postoperative course.

Early Dry Eye Testing: Multiple Benefits

As we have described in the instances above, preoperative testing for dry eye in cataract patients—and appropriate treatment when necessary—results in happier patients and enhances the reputation of the practice. We no longer have concerns about dissatisfied patients who will attribute their postoperative awareness of dry eye to the effects of our surgery. That's because their dry eye has been diagnosed and treated prior to their surgery. We no longer have concerns about less-than-ideal results with toric IOLs. Overall, we strongly endorse and encourage a proactive approach to diagnosing dry eye and effectively treating it preoperatively. The results are well worth the effort. OM

Kevin L. Waltz, OD, MD, and Brenda Wahl, OD, are in practice at Eye Surgeons of Indiana in Indianapolis. The authors report no financial interest in any of the products mentioned in this article. Dr. Waltz may be reached at KLWaltz@aol.com.