Ophthalmologists should adopt a 'wait-and-see' approach before putting new technologies into practice.
This article was reviewed by Tetsuro Oshika, MD, PhD
Newer does not necessarily mean better. That can be applied to many things, and it may be especially true in medicine.
New advances in viewing systems, IOLs, and femtosecond laser-assisted cataract surgery (FLACS) should be evaluated before they are incorporated into clinical practice, according to Tetsuro Oshika, MD, PhD, who detailed his views on how these technologies positively and negatively affect practice.
Surgical viewing systems
The conventional microscopy system is in some cases being replaced by three-dimensional digitally assisted visualization system, the so-called “heads-up” surgical system, especially during vitreous surgery.
Three such systems are currently available: the Ngenuity 3-D system (TrueVision Systems, Alcon), Artevo800 (Carl Zeiss Meditec), and RV800 Viewing System (Leica Microsystems).
“These systems clearly have an advantage in vitreous surgery, in that they provide an enhanced depth of field,” said Dr. Oshika, professor and chairman, Department of Ophthalmology, faculty of medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan. “In addition, the technology is a good educational tool because the systems allows everyone in the operating room to have the same surgical view as that of the surgeon.”
Other advantages in addition to the enhanced depth of field education offered by these systems include a 4,000-pixel monitor, decreased light phototoxicity, digital enhancements, digital filtering, and high dynamic range, Dr. Oshika pointed out.
“These clearly are beneficial for the patients,” he said.
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This raises the question about whether this technology also can benefit cataract surgeons.
There are some disadvantages that must be addressed, the first of which is latency-the lag in information delivery-that matters more in cataract surgery than in vitrectomy, Dr. Oshika pointed out, because cataract surgery is much faster than vitrectomy.
A second disadvantage involves ergonomics. The best distance to the monitor is about 1.2 meters.
“In many cases, the monitor should be placed next to the bed and not at the patient’s feet. The surgeon’s sightline is not always straight, which depends on the configuration of the operating room,” Dr. Oshika said.
Dr. Oshika cited a study (Graefes Arch Clin Exp Ophthalmol 2019;257:473-83) of surgeons’ responses to heads-up surgery that reported that the system was best used during retinal procedures, including peeling of internal limiting membranes and removal of epiretinal membranes, and the investigators considered that the procedure for which heads-up surgery was least beneficial was anterior segment surgery.
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“Some surgeons jump at the chance to use a new product for the first time and perhaps benefit from opportunities to speak about it,” he said.
Dr. Oshika explained that he is skeptical about new products such as the 3-D system being incorporated into practice until the advantages and disadvantages are weighed and the benefits for patients are clear.
A number of new IOLs become commercially available each year. The multifocal IOLs, which have been around for a while, are still associated with unwanted photic phenomena.
As a result, the percentage of unhappy patients remains relatively high, with percentages ranging from around 4% to 7% (Am J Ophthalmol 2019;208:133 and J Cataract Refract Surg 2009;35:992 and 2011;37:859). Preoperative examinations cannot predict which patients will experience photic phenomena.
Dr. Oshika noted that until recently, he was not a strong advocate of multifocal IOLs.
However, his opinion has been changing with the improvements in the IOL technology.
Related: Presbyopia-correcting IOLs: Expanding, improving last frontier
“Newer IOLs are associated with less loss of light energy postoperatively ranging from 14% down to 7%, specifically some trifocal, low-add, extended-depth-of-focus, and dual monofocal IOLs,” he said. “Less loss of light translates to fewer optical problems and better contrast sensitivity.”
Some older products have exhibited up to 22% light loss, Dr. Oshika added. Newer IOLs also have a better defocus curve with a smoother and wider range of focus.
Dr. Oshika added that in his current practice he uses a low-add (1.5-D) refractive IOL in the monofocal lens segment and a trifocal IOL in the multifocal lens segment.
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With its introduction in 2008, surgeons embraced FLACS enthusiastically with the idea that it would become standard practice, as when phacoemulsification supplanted extracapsular cataract extraction. However, over time the incidence of complications associated with FLACS was higher compared with manual phaco.
“There is no clear merit in terms of patient outcomes with FLACS,” Dr. Oshika said.
The survey of the American Society of Cataract and Refractive Surgery reported in 2018 that only 8% of patients undergo FLACS, with most respondents citing the cost and the lack of evidence to support the procedure’s clinical benefits.
Related: Achieving successful results with refractive cataract surgery
There are clear benefits to FLACS in certain clinical scenarios, such as cases with low endothelial cell counts, unstable zonules, displaced and subluxed lenses, and pediatric cataracts. Dr. Oshika also mentioned that the new FEMTIS IOL from Oculentis can be anchored in the perfectly circular capsulorhexis by four additional and specially designed haptics.
An alternative to FLACS is the Zepto capsulotomy system (Mynosys Cellular Devices Inc.), which can precisely create a centered capsulotomy using electrical energy delivered through a nitinol ring, which is a much cheaper version of FLACS, Dr. Oshika said.
However, Dr. Oshika noted that FLACS needs additional improvements in the future.
Moreover, Dr. Oshika concluded that newer is not necessarily better.
“The patient benefits should be evaluated before new technologies are incorporated into clinical practice,” he said.
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Tetsuro Oshika, MD, PhD
Dr. Oshika has no financial interest in this subject matter.