April 2018

REFRACTIVE

Device focus
Technologies that improve refractive surgery


by Michelle Stephenson EyeWorld Contributing Writer


 


LipiView II, LipiScan, and LipiFlow
Source: Johnson & Johnson Vision

Surgeons share what’s helped them improve refractive outcomes

Several technologies have revolutionized refractive surgery and improved patient outcomes. They allow surgeons to prepare the ocular surface for surgery and achieve results that are better than 20/20.

Tear film analysis

Both the TearLab Osmolarity Test (TearLab, San Diego) and LipiScan (Johnson & Johnson Vision, Santa Ana, California) are used for tear film analysis. According to John Hovanesian, MD, Laguna Hills, California, today’s refractive surgery patients are baby boomers, who are older. “Dry eye, and addressing it before surgery, can mean everything to their outcome. Many of these eyes are in a marginally compensated state. In other words, they aren’t symptomatic, but their eyes are somewhat dry. If a doctor doesn’t educate a patient about his or her dry eye before surgery, then the doctor owns that problem after surgery. It’s important that the patient understands that he or she has two problems: one that requires correcting refraction and one that requires correcting and treating dry eye,” he said.
Dr. Hovanesian uses this technology in older patients and in those who have symptoms only. George Waring, MD, Charleston, South Carolina, uses this technology on every lens refractive surgery patient and selectively for laser vision correction patients. “We take a holistic approach to eye care, and we have found that objectively, dry eye can result in fluctuation of vision as a result of increased light scatter. If we are going through the efforts of helping a patient relieve his or her dependence on glasses and contact lenses and improve overall vision, we think that we may be able to improve it even further if we address any underlying ocular surface issues and the overall health and wellness of the ocular surface,” he said.
He has found that even young patients can have meibomian gland dysfunction and blepharitis that may be due to computer vision syndrome.
Alan Carlson, MD, Durham, North Carolina, said that LipiScan, LipiView, and LipiFlow (Johnson & Johnson Vision) have been a huge asset in managing dryness. “These have also given us a lot more comfort performing LASIK procedures. Previously, we have been so worried that we would make dry patients even drier that our options were limited. Now, diagnostically evaluating these patients and therapeutically treating them has allowed us to take a lot of patients who are better suited for LASIK or SMILE and proceed with that rather than giving them PRK for a high correction that will have a much slower and unpredictable recovery,” he said.
Daniel Durrie, MD, Overland Park, Kansas, uses the TearLab test in select cases, and he uses LipiScan or LipiView on every patient. “As a screening on all of our refractive surgery patients, we want to make sure that their meibomian glands are functioning well,” he said.
“In short, LipiFlow works,” Dr. Hovanesian said. “It treats the most common type of dry eye that we see in young and old patients. When we see an abnormal tear film, we need to treat it. It’s a valid and valuable tool.”
Dr. Durrie agreed. He uses LipiFlow in patients who do not respond to lid hygiene.

Topography for corneal analysis

Topography provides thousands of points of data, in terms of curvature. “Not only does it help us identify the degree of corneal astigmatism, but it also provides a sense of surface irregularity, so it’s a poor man’s dry eye test as well,” Dr. Hovanesian said. “It’s standard of care to do some type of topography imaging.”
Dr. Waring agreed. “Topography and tomography are requisites for any form of refractive surgery. It’s the hallmark and foundation of refractive surgery, both cornea and lens-based refractive surgery. All patients should have topography and/or tomography. You cannot and should not be managing astigmatism without topography or tomography. This would prevent you from participating in presbyopia-correcting IOLs. Additionally, you would not be able to do toric IOLs because you can’t properly measure the magnitude or orientation of your astigmatism, and you can’t adequately screen for risk factors for the development of ectasia in laser vision correction unless you use topography. Lastly, you’re going to miss pathology that can affect your outcomes, such as keratoconus and/or epithelial basement membrane dystrophy, or even dry eye, in many cases,” he said.
Dr. Carlson said it has been especially helpful in ruling out patients for certain procedures, like LASIK. “We have much better technology to pick up early keratoconus, as well as the patients at risk for post-LASIK ectasia. It also gives us a better handle on stability of the refraction after contact lens wear. We see a lot of patients with hard lens wear, toric contact lens wear, and even soft lens wear in whom we want to make sure that they’ve been adequately out of their contact lenses. Topography and tomography together have been huge advances over the past 3 decades, but particularly over the past 10 years when it comes to refractive surgery and refractive cataract surgery,” he said.

Wavefront analysis

Dr. Hovanesian uses the WaveLight Contoura system (Alcon, Fort Worth, Texas), which is topography- guided treatment that evaluates the whole eye. “It’s important because there’s clearly a demonstrable difference in refractive outcome when you treat higher order aberrations as opposed to just lower order aberrations,” he said.
Dr. Waring uses high definition wavefront on all laser vision correction patients. “Now, we have extraordinarily powerful high definition aberrometers with the iDesign suite [Johnson & Johnson Vision] that measure more than 1,000 points of refractive data per eye that also account for chromatic aberration. We have seen a boost in our patients who are 20/15 and 20/10 with the advent of this advanced technology,” he said.
Dr. Durrie agreed. “We use wavefront when we’re going to do wavefront-guided surgery. We were in the iDesign clinical trials, and that was a significant improvement over the WaveScan. We have moved into a new era with the combination of WaveLight topography-guided ablation and the iDesign. I think both of these diagnostics have moved the bar up because we’ve seen more patients who are better than 20/20 with both of those,” he said.

HD Analyzer and iTrace

Dr. Hovanesian likes the HD Analyzer (Visiometrics, Costa Mesa, California) for many of the same reasons that he likes LipiScan. “The HD Analyzer looks at the whole eye and its image quality. The OSI of the HD Analyzer is valuable because if you’re going to do LASIK on someone who is 50 and has significant scatter from a cataract, you want to know about that because they’re not going to be happy. There’s an OSI tracing over time that will tell you how the scatter in the eye is changing as the patient blinks, and if you see wide variation there, you need to think more about the tear film as opposed to the static ocular media. Not only does the HD Analyzer give you an overall sense of the scatter in the patient’s eye but also the source of that scatter. I use it for every cataract patient, but not every LASIK patient,” he said.
Dr. Waring thinks the HD Analyzer represents a future paradigm in diagnostic testing because it’s one of the few devices that provides objective data on quality of vision. “This has been an invaluable tool for diagnosis, education, and management of dysfunctional lens syndrome at its various stages. Also, for dry eye evaluation, it’s one of the few devices that can give an objective, functional analysis of the impact of dry eye on vision. For subtle complaints, objective complaints, such as diplopia, this can be useful because we can identify the multiple points of light as they fall on the retina,” he said.
Dr. Waring has also found the iTrace (Tracey Technologies, Houston) to be useful for the ability to separate out internal aberrations from total aberrations and help surgeons determine whether the pathology is coming from the lens or the cornea. “It has a robust postoperative astigmatism program that can guide surgeons in evaluating postop astigmatism, particularly for understanding etiology and how to address residual astigmatism, that is, whether a rotation of an IOL would be warranted and how much. We’ve found it to be the most useful commercially available tool to do this analysis,” he said.

New technologies

As a group, these technologies have brought a combination of tear film diagnostics that have made surgeons even more aware of who needs to have treatment both before and after surgery and the topography-guided and wavefront-guided treatments that allow surgeons to achieve better than 20/20 vision. “It’s a fun time to be a refractive surgeon because we have good tools, and patients are getting good results,” Dr. Durrie said. “We know who to operate on and which one of the procedures in refractive surgery to do. It’s a great time for patients, and I think companies are now putting more resources into refractive surgery, and practices are starting to head in that direction also.”

Editors’ note: Dr. Hovanesian has financial interests with Alcon and
TearLab. Dr. Waring has financial interests with Johnson & Johnson Vision and Visiometrics. Drs. Carlson and Durrie have no financial interests related to their comments.

Contact information

Carlson
: alan.carlson@duke.edu
Durrie: ddurrie@durrievision.com
Hovanesian: jhovanesian@harvardeye.com
Waring: gwaring@waringvision.com

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