A First-of-its-Kind Corneal Lenticule Banking Service

A First-of-its-Kind Corneal Lenticule Banking Service 5 YOU NEED TO KNOW THINGS

by Jillian Webster

Could lenticules correct presbyopia? Everyone over 40 is keen to find out...

Recently, the Ministry of Health gave Cordlife Group Limited a go-signal to launch OptiQ, a groundbreaking corneal lenticule banking service in Singapore. This simply means that patients who are undergoing refractive surgeries can store their corneal lenticules to treat ocular conditions that may arise in the future.

According to Prof. Donald Tan, partner and senior consultant ophthalmic surgeon at Eye and Retina Surgeons, “a lenticule is a piece of the human cornea, which is shaped like a lens, taken from an individual.” These lenticules are removed during certain corrective refractive surgeries using the small incision lenticule extraction (SMILE) procedure, a FDA-approved method for correcting refractive eye problems.

These lenticules are now being stored by Cordlife for future use. Here are five things you need to know about the new corneal lenticule banking service in Singapore.

(SERI) after receiving a grant from the National Research Foundation (NRF) in Singapore to study glaucoma and cornea in 2007. “Within the corneal field, we were really looking at new ways to perform corneal transplants, as well as new refractive procedures,” Prof. Tan shared. “A lot 1The concept was born to avoid throwing away the lenticules removed during SMILE surgery. Prof. Tan got the idea for lenticule storage while he was heading the Singapore Eye Research Institute of these procedures, like laser-assisted in situ keratomileusis (LASIK), reshape the cornea. SMILE was a similar procedure to LASIK, but it had some advantages.” SMILE uses a single VisuMax (Carl Zeiss Meditec, Jena, Germany) femtosecond laser to remove a section of cornea, the lenticule. “We were doing SMILE surgery and all of these lenticules were being thrown away. I had the idea to store this tissue

and see what we can do with it,” Prof. Tan shared. He and his research team then established a series of experiments to see if they could store the material and reimplant it.

Prof. Tan thought that they could use it to treat presbyopia, or the gradual loss of the eye’s ability to focus on near objects. “Everybody around the world will have presbyopia as long as you are alive and you hit your 40s,” Prof. Tan said. “You will have some problem with your reading and will need some form of correction.” Presbyopia is commonly treated with plus powered lenses, such as contacts or reading glasses. According to Prof. Tan, “This lenticule [removed from the cornea of a myopia patient] is plus powered.” The professor was inspired to see if it was possible to store lenticules for future treatments.

removed, the team then had to find a 5Cordlife and OptiQ are the way to store them. “We did a sort of perfect partners in this modified cryopreservation where we froze the lenticules and stored them for three or four months,” Prof. Mehta said. important breakthrough in ophthalmology. They then reimplanted the lenticlue in the animal. Since 2012, Cordlife Group has been developing a sophisticated system After publishing the results of the of cryopreservation for the purposes animal trials showing lenticular of storing cord blood and tissue on implantation to be safe, they were the request of parents for disease then ready to move on to patient prevention. clinical trials. As lenticule removal surgeries, such as SMILE, became “Cordlife owns the largest network more popular, Prof. Mehta and his team of cord blood banks in Asia, with six had opportunities to conduct such internationally accredited storage trials. “With collaboration with a group cryogenic storage facilities in in Italy, we are able to do lenticule Singapore, Malaysia, Hong Kong, implantation on almost 70 patients Indonesia, the Philippines and India,” under the European guidelines,” said shared Ms. Tan Poh Lan, group chief Prof. Mehta. executive at Cordlife Group Limited. 2 4Initial trials were conducted on monkeys. Prof. Tan along with his colleague, Prof. Jod Mehta, head and senior consultant for the Corneal and External Eye Disease Department at the Singapore National Eye Center (SNEC), devised an experiment to test their hypothesis. They conducted their initial trials on There are several indications for the use of lenticules. Prof. Mehta cited a clinical study of nine patients who showed absolute clarity when the lenticule was implanted inside the eye. “These are very similar results to what we saw when we were doing these studies in animals. But now this has been replicated in humans,” he shared. As “OptiQ was a natural extension of our services,” Ms. Tan added. As well as a number of other diagnostic services, Cordlife Group’s expertise in the process of cryopreservation is the gold standard and the natural choice for the preservation of corneal lenticules. “This partnership with SERI fits perfectly with our commitment to providing innovative healthcare services,” she said. OptiQ is the first corneal lenticule monkeys. “We used research monkeys more people choose lenticule removal storage facility in the world. The corneal where we actually did the SMILE surgery, like SMILE, there will be lenticules are collected from clinics, procedure, extracted the lenticule, greater opportunities for more lenticule upon request of the patient, where the stored it, waited a few months, and implantation clinical trials. extraction surgeries occur and are then then reimplanted it back in,” shared brought to Cordlife facilities. They are Prof. Tan. Prof. Mehta explained that there then processed and then preserved. are several indications for the use Dr. Tang Kin Fai, laboratory director Prof. Tan and Prof. Mehta had an idea of lenticules. “Lenticule extraction at Cordlife Group, explained that for something new: additive technology. procedure is currently being done for lenticules are stored in at least -150 “We were putting something into the myopia, myoptic astigmatism and degrees celsius in a “vapor phase liquid cornea now,” said Prof. Tan. “So when hyperopia. Lenticule implantation is nitrogen tank until the day it is needed you implant a lenticule, firstly, you’re mainly being done for hyperopia, which by the patient.” reversing what we did all those years is longsightedness, and presbyopia, ago. Secondly, you are also implanting which is near vision correction,” he “The results of the clinical trials provide something that can be removed, giving said. Once extracted, the lenticule can an important breakthrough in the field the surgeons ‘ultimate flexibility’ with then be stored at the right temperature, of ophthalmology. We are excited to this biological resource.” indefinitely. be part of this revolution,” Ms. Tan

3concluded. Once Prof. Tan and Prof. Mehta were Lenticules are stored through convinced that this tissue could be As more and more people choose modified cryopreservation. stored and then reimplanted, they lenticule extraction, the practicality needed a safe and tested means of of lenticule storage and implantation Prof. Mehta described the first years of cryopreservation. “Now we have this will become more and more apparent. research: “The primary work we initially procedure as a clinical application, we The launch of OptiQ is an exciting step did on animals in Singapore at our are storing the cryopreservation with forward in the fight against blindness. research facility at SERI was focused Cordlife for long-term storage,” shared on showing that it was safe to implant Prof. Mehta. the lenticule.” Once the lenticules are

Joint APGS-ISGS

Webinar by Hazlin Hassan Top Highlights

If you missed the virtual joint AsiaPacific Glaucoma Society (APGS) and International Society of Glaucoma

Surgery (ISGS) Webinar on “Current

Paradigms in Glaucoma Surgery” held in February 2021, fret not — because we’re here to give you the high points from the event.

Endoscopy-assisted vitrectomy provides good results when it comes to surgical management of malignant glaucoma.

Malignant glaucoma, characterized by a shallow or flat anterior chamber and high intraocular pressure (IOP) — usually after intraocular interventions — has an acute onset and is visually devastating. Medical management has a high rate of failure of between 85-100 percent and surgical intervention is normally challenging.

“With endoscopy-assisted vitrectomy, the surgeon can obtain better visualization through the corneal edema and the non-dilated pupil, a common problem in malignant glaucoma eyes,” said Dr. Do Tan, chief of the Glaucoma Department, Vietnam National Institute of Ophthalmology, Vietnam. “Also with endoscopy-assisted vitrectomy, you can get better access to the far peripheral vitreous base,” he added. “You can preserve the posterior capsule easily, and it is easier for the surgeon to photocoagulate the ciliary processes, if needed, to control the IOP.” Dr. Tan shared the results of a study of 53 eyes from 26 patients with malignant glaucoma, where endoscopyassisted vitrectomy was carried out to restore the anterior chamber (AC) and control IOP after failed medical and laser treatments.

After one year follow-up, a total of 94.3% had improved best corrected visual acuity (BCVA); 100% saw AC reform; and 93% saw their IOP come under control. A total of 35.8% needed some additional IOP lowering meds, but there were no serious complications. The final success (complete and relative) ratio was 97.1%.

“In conclusion, the endoscopy-assisted vitrectomy is a very good surgical method for malignant glaucoma,” said Dr. Tan.

Scuba divers also know a thing or two about pressure…

Controlled hypotony can be used in filtering surgery to achieve low IOP with relatively small complications.

“The use of devices or shunts, controlled short-term over-drainage or hypotony, wide application of mitomycin C (MMC), surgical technique modification, intensive post-op intervention and ocular massage, improve outcomes for patients,” said Prof. Prin Rojanapongpun, MD, consultant at the Bumrungrad International, Sukumvit Hospital and MedPark Hospital, Bangkok, Thailand.

Prof. Rojanapongpun shared a case of a 73-year-old male, followed over five years, with hypotony but with the AC maintained and without permanent visual loss.

“Is hypotony a problem? Based on the consensus of the World Glaucoma Association, low IOP by itself should not necessarily be considered as a complication or a criterion for failure, if low IOP does not lead to maculopathy, choroidal effusions or worse vision,” he said.

He added that there is no reliable way to control scar formation in filtering surgery, and Asian patients have the propensity for scarring. “A failed filtering bleb is common in Asian and African patients,” he continued. The key to a perfect filtering is to be able to control the aqueous flow and wound healing.

MMC can improve the outcome of filtering surgery in Asians, who tend to have a higher risk of scarring compared to Caucasian patients. “We need a big change in filtering surgery,” Prof. Rojanapongpun added. What is needed are devices or shunts to control flow, a standardized lumen with less variables, a large flap area and a large bleb to control abrupt aqueous egress.

A low IOP should be the target during early post-operative follow-up. In essence, what is needed, according to Prof. Rojanapongpun, is a system that creates a controlled hypotony, and can overcome wound healing for long-term success.

The PAUL Glaucoma Implant (PGI) regulates IOP in the patient’s eye and prevents further progression of the disease — a promising alternative to current aqueous shunts.

Studies have shown that a new implant for the treatment of moderate to severe glaucoma demonstrates comparable efficacy with other currently available implants. Almost three-quarters of enrolled patients with refractory glaucoma achieved complete surgical success after one year of follow-up.

Trabeculectomies with MMC (29%) have a higher rate of reoperation for glaucoma than tube-shunt surgery (9%), as well as a higher rate of failure. Thus, the mainstay of treatment has been tube implants. However, according to Prof. Paul Chew, senior consultant, Glaucoma Division, National University Hospital, Singapore, current-day implants still do not provide very good outcomes, with almost half failing by one year.

“Is there a better glaucoma implant design? This has to do with making sure there is a better plate size, a better tube caliber, and whether a valve is really necessary,” said Prof. Chew.

Prof. Chew’s PAUL Glaucoma Implant (PGI) was created as part of an effort to produce a better implant design and construction and to plug the gap for better treatments that address the needs of severe disease, which often do not respond to primary treatments and can cause vision loss.

The PGI is a glaucoma drainage device designed to treat glaucoma by regulating IOP in the patient’s eye and preventing further progression of the disease. Constructed from medical implantable grade silicone, it has a

Unfortunately, hiding from glaucoma is not an effective treatment.

length of 44.9mm, a width of 23mm and an extraocular plate surface area of 342.1mm2. It differentiates itself from other shunts by its small tube caliber.

Results for the PGI’s efficacy and safety evidence show a promising outlook after one-year multicenter trials in the U.K. and Asia, and two-year trials in Singapore. “In one year, we had 4 failures, 69% were complete successes and 93% were considered qualified successes. This is quite a high level of success in the treatment group,” explained Prof. Chew.

In conclusion, the PGI, with its lower caliber tube, appears to offer a promising alternative to current aqueous shunts, such as the Baerveldt Glaucoma Implant, in terms of safety, and efficacy in the treatment of refractory glaucoma.

Editor’s Note:

The virtual joint Asia-Pacific Glaucoma Society (APGS) — International Society of Glaucoma Surgery (ISGS) Webinar on Current Paradigms in Glaucoma Surgery was held on February 6, 2021. Reporting for this story also took place during the APGSISGS Webinar.