by Matt Young
Right after the Paris runway at the 37th Congress of the European Society of Cataract and Refractive Surgeons (ESCRS 2019), CAKE magazine next landed in the beautiful city of Kyoto, the former capital of Japan, to discover innovations in the fields of cataract and refractive surgery at the Annual Meeting of the Asia-Pacific Association of Cataract and Refractive Surgeons (APACRS 2019).
Aptly themed Elegance and Innovation, the APACRS 2019 presented the latest cutting-edge products and techniques in this ever-evolving field, shared by renowned ophthalmologists from around the world.
Located in a venue rich in history and tradition, the titles of the APACRS symposia reflected the Japanese culture. Among them include the ‘Sumo’ session on the challenges in refractive surgery and the ‘Umami’ session, which tackled astigmatism correction in cataract surgery and other non-phaco and intraocular lens (IOL)-related issues.
Below are some insights from the intriguingly titled session: ‘Katana’ on ‘The Cutting Edge in Phaco and IOLs’.
So, what exactly is a katana?
In days of yore, the heroic samurai of ancient and feudal Japan relied on the katana, a Japanese sword with a curved, single-edged blade. According to Western historians, the katana was among the finest cutting weapons in world military history. Eye surgeons, on the other hand, can count on their trusty surgical instruments.
The Cutting-Edge Katanas of Cataract Surgery
According to Dr. Oliver Findl from the Vienna Institute for Research in Ocular Surgery, and Hanusch Hospital, Vienna, Austria, one can also rely on measurements to enhance toric outcomes.
He said that different corneal measurements cannot be used interchangeably. He also advised to use a combination of different measurement methods for toric IOL calculation.
Swept-source optical coherence tomography (SS-OCT) appears to be more accurate compared to Scheimpflug imaging. Dr. Findl noted that the main source of error in toric-IOL calculation is the corneal measurement. His advice? “Use three different devices and at least two different measurement techniques.”
“Doubt your corneal measurements and repeat them, if necessary,” he urged, especially for patients with conditions such as dry eye, and irregular cornea.
Meanwhile, Professor Soon-Phaik Chee, from the Singapore National Eye Centre (SNEC), talked about the CAPSULaser, a selective non-contact non-pulsatile laser that creates a capsulotomy in less than a second. She said that problems with femtosecond laser-assisted cataract surgery (FLACS) included the cost. It also requires additional room and an additional set of staff, while also affecting patient flow.
Meanwhile, ZEPTO, the precision pulse capsulotomy device from Mynosys (Fremont, CA, USA), requires un-scrubbed staff to assist, one of its limitations. She concluded that the CAPSULaser has its advantages including its selective thermal laser capsulotomy and it does not disrupt the patient flow.
Some biomaterials are purer than others, said Professor Gerd Auffarth from the International Vision Correction Research Centre, Germany, during the session.
He noted that a purity study on hydrophobic acrylic IOL material comparing Hoya’s Vivinex, Alcon’s SN60WF and J&J Vision’s Tecnis showed that hydrophobic-acrylic IOL models differ in their resistance to develop glistenings and glistening patterns.
Glistenings do not reduce visual acuity but increase ‘straylight’, which can cause patients to be blinded by oncoming car headlights and hazy vision.
In the study, an accelerated aging protocol was used to induce glistenings, or microvacuoles, in hydrophobic acrylic IOLs. The IOLs were warmed to 45°C and then cooled to 37°C.
“Although less severe, the glistening problem needs to be addressed by the IOL manufacturer through either the introduction of new materials or by continuous improvement of the manufacturing process,” concluded Prof. Auffarth.
Of Rapid Innovations and Wider Treatment Options
Rapid innovation in medical devices and medications has resulted in a wider and better range of treatment options in cataract surgery. This allows cataract surgeons to plan and design treatments accordingly to help to meet patient expectations, as well as improve vision and quality of life.
Dr. Hiroyuki Arai from the Queen’s Eye Clinic, Japan, discussed selecting appropriate intraocular lenses (IOLs) for individual patients in a paper called Optimize Outcomes with the Choice of IOLs and Innovations.
IOL options have expanded with the emergence of multifocal and extended depth of focus (EDoF) lens. In this vein, Dr. Arai introduced a new IOL – the LENTIS Comfort – which was launched in April last year. The IOL has been approved in Japan and is covered by the Japanese national health insurance program. Dr. Arai emphasized that this low-add segmental IOL is designed to minimize light loss and has almost no glare and halos.
Postoperative Dry Eye Management
Dry eye disease (DED) after cataract surgery has become a critical concern, and various treatments have been developed to counter this condition. “Most cataract surgery patients have prior ocular surface disease (OSD),” said Adjunct Associate Professor Lim Li from the Singapore National Eye Centre (SNEC).
Clinical signs of dry eye are commonly found in cataract patients before surgery. “However, the majority of patients were asymptomatic or minimally symptomatic,” said Prof. Lim about a recent study. Seventy-seven percent of eyes had abnormal corneal staining and more than 60% of patients had an abnormal tear film break-up time (TBUT). Additionally, a blurred vision was more likely than burning or foreign body sensation.
So, why is it important to manage the ocular surface?
Preoperative biometry and topography could be affected, as well as postoperative outcomes, like visual and refractive results. According to Prof. Lim, studies have shown that hyperosmolarity of the tear film is associated with significantly more variability in average keratometry readings and anterior corneal astigmatism. This may result in significant differences in IOL power calculations.
“Corneal staining is the single most critical sign of OSD that should be normalized before cataract and refractive surgery,” said Prof. Lim.
Artificial tear preparations, such as Hialid (Santen Pharmaceutical, Tokyo, Japan), which contain various polymers like cellulose derivatives and hyaluronic acid, are the first-line treatments for dry eye symptoms after cataract and refractive surgery due to their effectiveness in alleviating symptoms of dry eye after cataract surgery.
Therapeutic contact lenses may be beneficial for severe OSD, including corneal ulcers, persistent epithelial defects, corneal perforation, and chemical burns. Bandage lens may be used in the preoperative setting to allow epithelial healing of punctate keratitis before preoperative biometry measurements.
“Visually significant (VS) OSD leads to reduced visual quality and potential errors in preoperative measurements,” cautioned Prof. Lim. In short, according to him, it is important to identify VS OSD patients, defer preoperative measurements until fully treated and resolved (as they can be affected), postpone surgery, and treat patients before surgery to achieve an optimal outcome.
“A study found that the use of an aspirating speculum aggravated dry eye parameters during the early postoperative period after cataract surgery,” said Professor Jong Suk Song from the Korea University College of Medicine in South Korea.
Cataract surgery can also worsen ocular surface parameters and aggravate dry eye disease. Therefore, he advised physicians to aggressively treat cataract patients with existing dry eye disease.
In addition, increased incision extent, operation time, irrigation and microscopic-light exposure time decreased the TBUT and goblet cell density. And the use of topical eye drops after cataract surgery can worsen the goblet cell density. Conjunctival goblet cell loss in dry eye is associated with ocular surface inflammation.
According to Prof. Jong, studies have revealed that preservative-free diquafosol showed better efficacy in treating DED after cataract surgery than preservative-containing diquafosol or preservative-free hyaluronate. “Therefore, preservative-free diquafosol may serve as a reliable option for the management of patients with pre-existing DED after phacoemulsification,” he concluded.
These practical tips from renowned surgeons should help to manage patients’ expectations and improve satisfaction – which is valuable advice for any cataract surgery practice.
Can You Take the Heat… In the OT?
In the popular Japanese cooking show ‘Iron Chef’, contestants battle each other to win the title. Sometimes exotic ingredients are thrown into the mix to flummox participants. Similarly, while most cataract surgeries are routine, surgeons are occasionally faced with challenging cases.
During the ‘Iron Chef’ session at APACRS 2019, which tackled ‘Challenging Cataract Surgery’, several experts shared their experiences and insights on various problematic scenarios.
“There are many complications when it comes to cataract surgery for the elderly,” said Dr. Hisaharu Suzuki from Zengyo Suzuki Eye Clinic and Nippon Medical School, Japan. These include a hard nucleus, weak zonular fibers, corneal endothelial cell loss, myosis, and glaucoma. Therefore, considerable preparation is required for cataract surgery in the elderly.
“Congenital cataracts are complicated,” added Dr. Zhao Yun-E, from the Eye Hospital of Wenzhou Medical University, China. They are always idiopathic, involve complicated and difficult operations, often entail numerous complications, and have uncertain clinical outcomes in the long-term.
She advised diagnosing before surgery, avoiding cortex shrinking for cases of posterior capsule defect (PCD), preventing hemorrhage for those with persistent fetal vasculature (PFV), and suturing the incisions.
Wrestling with Challenges in Refractive Surgery
Meanwhile, in the ‘Sumo’ session, the audience heard from various refractive surgery experts on the latest innovations.
Professor Kimiya Shimizu, M.D., from the Sanno Eye Center, Japan, presented the latest developments and clinical results on the ICL KS-AquaPORT, which he developed. (Note: The KS stands for his initials.)
He said that the visual performance of Implantable Collamer Lens (ICL) is better than laser-assisted in situ keratomileusis (LASIK), and is also reversible. In summary, he said that the ICL KS-AP is safe, efficient, provides high predictability, offers stable refraction, and is shown to have no complications in his patients since 2007.
“The most commonly performed corneal refractive surgery procedures in the past decade changed from LASIK to surface ablation (SA),” said Dr. Cordelia Chan, from Eye Surgeons@Novena & Napier, Singapore.
In 2005, 81% of surveyed patients in Korea had LASIK and only 15% had SA. But 10 years later, in 2015, 40% had SA, while 35% had LASIK. The main reasons for this shift were due to a fear of flap-related complications and because Koreans have a relatively thin central cornea.
However, LASIK has its strengths, namely that it offers excellent and stable vision, quick recovery and short downtime, with minimal or no haze and minimal pain.
In a study comparing femto-LASIK versus photorefractive keratectomy (PRK), Dr. Chan said both groups saw excellent safety profiles, but LASIK saw a faster visual recovery at 1 month. But LASIK did have potential problems, such as more dry eye, tears, buttonholes, diffuse lamellar keratitis, epithelial ingrowth, flap dislodgement, rainbow glare, and ectasia risk.
Small incision lenticule extraction (SMILE), on the other hand, according to Dr. Chan, had good outcomes but saw some variability. Plus, dissection can be tricky for an inexperienced surgeon due to the thin lenticule. Visual recovery was slower compared to LASIK, but faster than PRK, and with less pain.
Moreover, Dr. Chan noted that she no longer performs Epi-LASIK due to cases of stromal incursions among patients at her center.
Her preference for low to moderate myopia is femto-LASIK for the fastest visual recovery, comfortable postoperative recovery, and excellent safety, efficacy and predictability profiles.
To LASIK or to SMILE, That Is the Question
“A study comparing wavefront-guided LASIK versus SMILE showed that both provided excellent clinical outcomes and predictability,” said Dr. Edward Manche, professor of ophthalmology at Byers Eye Institute, Stanford University School of Medicine.
He said there was no difference in the induction of higher-order aberrations, but added there was a faster visual recovery in the WFG-LASIK group. There was also better uncorrected and corrected distance visual acuity (UDVA) at 20/16 or better in the WFG-LASIK group.
On the other hand, Associate Professor Marcus Ang from the Singapore National Eye Centre (SNEC) said that a study on intraoperative patient experience and postoperative visual quality after SMILE and LASIK found that SMILE achieved good refractive predictability at 3 months.
“Secondary outcomes such as safety, efficacy and stability for SMILE at 3 and 12 months were similar to LASIK,” he said.
Dr. Ang noted that intra-operative experience was similar between SMILE and LASIK except for surgical manipulation, which was more uncomfortable during SMILE compared to LASIK. He added that at 1 month after surgery, patients had similar symptom scores between eyes, except more occasional blurring with SMILE compared to LASIK.
Other fascinating sessions at APACRS included the ‘Wisdom of the Samurai’, in which experts presented subtle surgical tips and maneuvers that other surgeons can bring home and use the next time they are in the OT.
Editor’s Note: A version of this article was first published in CAKE Today, CAKE Magazine’s electronic daily congress news, Media MICE’s daily at the Asia-Pacific Association of Cataract and Refractive Surgeons annual meeting (APACRS 2019) held in Kyoto, Japan, on October 3-5, 2019.
