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January 2013 Feature Article Read Refractive Surgery Outlook New Dry Eye Technology Could Improve Refractive OutcomesBy Linda Roach One of the most important steps a refractive surgeon can take to improve visual outcomes is to find and treat every undiagnosed case of dry eye, blepharitis and meibomian gland dysfunction (MGD) among prospective patients. This interest in dry eye detection has led some surgeons to adopt new diagnostic tools and innovative treatments. Vigilance for dry eye Matteo Piovella, MD, founder and clinical director of the CMA Outpatient Microsurgery Center in Monza, Italy, said he began looking more closely for dry eye before surgery due to lens power errors in his multifocal or other premium intraocular lens (IOL) cases. “Sometimes, even though we had a great preop routine on all patients, including biometry, we failed to get the perfect, plano result we wanted after cataract surgery. We took out the cataracts, but the patients still had blur,” said Dr. Piovella, who is president of the Italian Ophthalmological Society (SOI). “We discovered that what we were seeing was not predictive error, but measurement error caused by unstable tear film from dry eye syndrome. “When there is even mild dry eye, you can have a mistake of 1D or more in the K1 and K2 parameters of the corneal surface. And this naturally creates a mistake in the power of the IOL,” he said. So when he detects dry eye, Dr. Piovella tells patients to use artificial tears for a week. Then he repeats the tests to verify that the tear film and the K1 and K2 readings are stable before cataract surgery is performed. William Trattler, MD, a refractive surgeon and director of cornea at the Center for Excellence in Eye Care in Miami, agreed. “Dry eye can impact the corneal photography, keratometry readings, topography and IOL power selection. So it makes sense to treat the dry eye first and remeasure the eyes later,” he said. High-tech tool #1: Interferometry For the past six months, Dr. Piovella’s surgery practice has used a high-tech tool that he recommends for preventing missed diagnoses of dry eye and MGD: tear film lipid layer interferometry (LipiView, TearScience, Morrisville, N.C.; and others). “This is a critical test for us,” Dr. Piovella said. “All the patients who undergo cataract surgery, all the patients who undergo laser vision correction and all the patients who say they are feeling ocular surface discomfort are directed to the interferometer, to determine if they have abnormal tear film.” Dr. Trattler reported in 2010 on a study1 that suggested one reason dry eye and MGD have been underdiagnosed by refractive and cataract surgeons is that the conditions, though common, can be asymptomatic. The prospective, multicenter study found that 76.8 percent of the 272 eyes in the study had corneal staining; in 50 percent of the study eyes the staining was located centrally. The study also asked the 136 patients scheduled for cataract surgery (272 eyes) if they ever experienced a foreign-body sensation in their eyes; 59 percent answered “never,” and only 13 percent said they felt this way half, much or all of the time. However, tests of tear film breakup time (TFBUT) — defined as the interval between the last complete blink and the first appearance of a dry spot or disruption in the tear film — found that 63 percent of the subjects had abnormally low results. Their mean TFBUT was 4.95 seconds (dry eye: less than or equal to 5 seconds; normal: greater than or equal to 7). Another study of 100 pre-cataract surgery patients found that 59 percent had blepharitis. Interferometry is based on the observation and recording by an interference camera of color interference patterns in zones of specular reflection. The reflection patterns provide information about the superficial tear lipid layer’s thickness and lipid content. Based on a color comparison table that correlates with thicknesses of the lipid layer, the tear layer is semi-quantitatively graded for dry eye severity, and the lipid layer is quantified. Dr. Piovella said information gathered by this noninvasive method has proved valuable in his everyday surgical practice. “When we are confronted with interferometer results that demonstrate too low a percentage of the lipidic part of the tears, we try to increase the production of meibum before we do the surgery,” Dr. Piovella said. “We delay surgery until the tears are normalized on the interferometer.” He credits interferometry’s inclusion in his preop protocols with reducing IOL target error, eliminating prolonged corneal discomfort from dry eye after laser refractive surgery and preventing unhappy patients. “If we follow this prevention routine, we do not have any problem lubricating the surface with tears in the three months after laser refractive surgery,” he said. High-tech tool #2: LipiFlow The interferometer that Dr. Piovella uses is a companion to a device whose primary function is treating MGD, the LipiFlow Thermal Pulsation System (TearScience). LipiFlow drew attention from clinicians last November at the Annual Meeting of ISRS and the Academy’s Annual Meeting. At a crowded breakfast demonstration, an ophthalmologist volunteer with chronic dry eye and MGD leaned back in his chair and underwent a 12-minute heated eyelid massage in one eye. The other eye was treated at the ASCRS meeting the previous spring, and the volunteer said he was back onstage for a second treatment because the first had improved his symptoms so much. This device was designed to restore the tear film in eyes in which the meibomian glands have slowed or stopped their normal release of lipid-rich meibum onto the ocular surface. It also is equipped for examining the meibomian gland and for interferometry. LipiFlow heats the glands to 42.5 degrees Celsius to loosen and thin their contents. Then it expresses the contents by rhythmically pushing two air bladders against the eyelids. Ideally, this allows the glands to begin lubricating the ocular surface again, improving the quality of the tear film and moderating the patient’s dry eye symptoms. The therapeutic effects wane in six to 12 months, the company says. In a paper published last year in the journal Cornea,2 Lane et al. reported positive results from a prospective, open-label, randomized, crossover multicenter clinical trial that compared a single bilateral LipiFlow session with a waterless and portable warm compress system (iHeat®; Advanced Vision Research, Woburn, Mass.) in 139 MGD patients. The LipiFlow group had a statistically significant improvement (P < 0.05) in meibomian gland secretions at two and four weeks. TFBUT also was improved to the same level of significance (mean ± standard deviation at baseline: 5.5 ± 2.9; two weeks: 6.9 ± 5.0; four weeks: 7.4 ± 5.5). The control group showed no change in those markers.2 [Click here and here to see videos about LipiFlow.] The treatment does not work for everyone, but it helps some patients a great deal, Dr. Piovella said. “These patients who are suffering from dry eye for a long time can get absolutely extraordinary improvement of something that they have been suffering for years,” he said. Furthermore, it can help normalize the tear film and the ocular surface, enabling surgery to take place, he added. If basic tests indicate MGD, and little or no meibum can be expressed during the clinical exam, he assesses the tear film with the interferometer and recommends a LipiFlow treatment (which is not included in the flat fees he charges for refractive and cataract procedures). The verdict is not unanimously positive, however. “I do have a LipiFlow, and I find it to be a good treatment for patients with mild to moderate blepharitis,” Dr. Trattler said. “But the challenge is cost. It isn’t paid for by insurance.” Rolando Toyos, MD, surgical director of the Toyos Clinic, of Nashville/Memphis, Tenn., said patients sometimes come to him for an alternative treatment a few days after being treated unsuccessfully with LipiFlow elsewhere. “I think it’s part of the armentarium of things to do. But when I used it, I found that LipiFlow doesn’t do a good job [of clearing out] the outer glands. I also think patients would appreciate it more if the price of the treatments were less,” Dr. Toyos said. He instead prefers to address their MGD with Intense Pulsed Light (IPL) therapy, which he developed after his laser facial rejuvenation patients reported that their pre-existing dry eye had improved after their cosmetic procedure. He will report at the ARVO meeting this year on a three-year retrospective study of MGD patients he treated with IPL. Approximately 300 LipiFlow systems are in medical/surgical practices worldwide, primarily in North America, said Tim Willis, president and CEO of TearScience. In 2013, the company will target its marketing efforts at international ophthalmologists, he said. Currently, there are a few machines in Germany, France and the United Kingdom, and Dr. Piovella’s is the first in Italy, he said. Waiting to launch until 2013 gave TearScience time to petition private insurers in individual European countries to cover LipiFlow treatments, he said. “We just literally got approval of private insurance payment in Germany in the fourth quarter of last year,” he said. He provided additional information he says ophthalmologists may want to know before purchasing LipiFlow:
High-tech tool #3: Oculus Keratograph 5M When the first version of Keratograph (Oculus, Arlington, Wash.) came on the market in the late 1990s, it was a corneal topographer. Today’s fifth-generation model, the Keratograph 5M, features a suite of evaluation tools that offer clinicians new, objective ways to assess and monitor dry eye and MGD, Dr. Toyos said. In addition to corneal topography, the Keratograph 5M also performs keratometry, meibography and computerized classification of bulbar redness (an aid in assessing the effectiveness of preop dry eye therapy). It includes a high-definition camera for taking photos and recording video; measures tear meniscus height with computer precision; and performs noninvasive, computer-controlled testing of TFBUT. The repeatability of the Keratograph’s measurements make it an objective, reliable device for assessing dry eye therapy, according to investigators who conducted a study that validated the device’s tear breakup testing software (which they called NIK-BUT).3 “The noninvasive tear film break-up time is measured automatically and thus objectively, without the operator influencing the outcome. Thus NIK-BUT circumvents two error sources involved in the [conventional] BUT method,” they wrote. “The latter requires fluorescein application, which can distort outcomes by affecting the composition of the tear film, as well as through the difficulty of reproducible dosage.” Dr. Toyos agreed. “It’s an objective test. It takes the doctor out of it,” he said. “Then it gives you a picture of exactly where the cornea is drying out. I’ve been amazed at how closely it correlates to patient symptoms. Patients say, ‘I feel the dryness right here,’ and it shows up on the picture.” The precision by which it tests breakup time also might make the fifth-generation Keratograph useful for dry eye research, in which the use of conventional, subjective tests often has made it difficult to judge the reliability of study conclusions and to compare results between studies. Indeed, the consensus reports issued by international expert panels on dry eye4 and MGD5 cited this lack of objective, repeatable tests as an impediment to the progress of research on ocular surface disorders. But because the device’s computer-determined times for tear film breakup do not depend on the examiner to react to the patient’s first blink, the figures are slightly lower than conventional tests, he said. “It’s more sensitive than the usual fluorescein test, so the times are a little lower than you would personally record. But the major point is that it’s doing an objective measurement of how the ocular surface is faring,” Dr. Toyos said. He said that when he expresses the meibomian glands after an IPL treatment, he documents it with the Keratograph’s high-definition video camera. As a topographer, the Keratograph maps the contours of the cornea’s anterior surface, so it cannot replace the Oculus Pentacam for complicated surgical planning, he said. “We need our Pentacam to measure the anterior and posterior surface of the cornea. But if you have just a basic dry eye clinic, and you’re not doing premium surgeries with premium intraocular lenses, the Keratograph will meet your needs.” Two alternative treatments for MGD Both in studies of efficacy and in commercial availability, LipiFlow has a big head start on two other innovative methods for treating MGD. But the techniques have slowly taken a nontraditional route into ophthalmic practices in recent years, although the publication record on them is sparse. These novel approaches are the Maskin Meibomian Gland Intraductal Probes (Rhein Medical, St. Petersburg, Fla.) and Dr. Toyos’ IPL therapy. Meibomian gland intraductal probes Patients and physicians alike often learn about the existence of his procedure from the Internet, where procedure videos and patient testimonials are posted at the Rhein Medical YouTube channel [link] and on the Rhein website [link]. Ophthalmologists in the U.S., Germany, Japan, Australia and South America have responded by adding Maskin probes to their therapeutic armentarium, Dr. Maskin said. He is passionate about advocating for wider use and believes his work so far suggests it is effective. Typically, probing restores functionality of the glands in a week, and the relief of previous dry eye symptoms lasts about a year, he said. There is one published study on the treatment in the peer-reviewed literature. In it, Dr. Maskin reports that 24 of 25 patients (96 percent) had immediate post-probing relief, and all 25 had relief of symptoms by four weeks after the procedure.6 Twenty patients (80 percent) only required a single treatment and went an average of 11.5 months before retreatment. Five patients required retreatment at a mean of 4.6 months. Patients frequently reported improvement in newly recognized but previously subclinical symptoms, supporting the notion that MGD exists subclinically in some patients, the study reported. IPL therapy He has not published in peer-reviewed journals about the technique. However, he is scheduled to present the results of a three-year retrospective study of IPL outcomes this year at the annual research meeting of ARVO. Dr. Toyos dismissed a 2011 report about two cases of ocular damage from IPL.6,7 If the eye is shielded from the 500 nm light, there is no damage to the eye when the lids are treated with flashes of pulsing light, he said. That case study’s authors agreed that protection is needed, and wrote: “The pigmented iris absorbs light in the same wavelength range of IPL, thus remaining vulnerable to IPL exposure, especially when applied to the periocular area. The fact that IPL is not a laser may give people a false sense of security regarding damage to the eye. The cases presented give evidence that periorbital IPL treatment may permanently affect pigmented intraocular structures. It is imperative for treating physicians to be aware of these hazards and to use appropriate eye protection to prevent ocular damage.” Click here for videos about IPL. REFERENCES 1. Trattler W, Goldberg D, Reilly C. Incidence of concomitant cataract and dry eye:prospective health assessment of cataract patients. Presented at: World Cornea Congress; April 8,2010; Boston, MA. 2. Lane SS, DuBiner HB, Epstein RJ, et al. A new system, the LipiFlow, for the treatment of meibomian gland dysfunction. Cornea. 2012;31(4):396-404. 3. Wiedemann D et al. Validation of new non-invasive methods for tear film assessment using a Keratograph. Translation of an article originally published in German in Die Kontaktlinse, August 2010. Accessed Jan. 8, 2013 at: http://www.oculus.de/us/sites/detail_ger.php?page=484 4. 2007 Report of the International Dry Eye WorkShop (DEWS). Ocul Surf. 2007;5(2):67-142. Free download in multiple languages at www.tfos.org. 5. Report of the international workshop on meibomian gland dysfunction. Invest Ophthalmol Vis Sci. 2011;52(4). Free download in multiple languages at www.tfos.org. 6. Maskin SL. Intraductal meibomian gland probing relieves symptoms of obstructive meibomian gland dysfunction. Cornea. 2010;29(10):1145-1152. 7. Lee WW, Murdock J, Albini TA, O'brien TP, Levine ML. Ocular damage secondary to intense pulse light therapy to the face. Ophthal Plast Reconstr Surg. 2011;27(4):263-265. 8. Toyos R, Jordan J. Re: "ocular damage secondary to intense pulse light therapy to the face". Ophthal Plast Reconstr Surg. 2012 Mar;28(2):155; author reply; 155-6. |
