MIGS breaks through barriers in developing world
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Minimally invasive glaucoma surgery could potentially offer an effective alternative to lifelong use of medications at a global level.
MIGS may also be useful for overcoming many of the issues related to medication availability, side effects, cost and compliance, and it could also avoid or postpone the need for more invasive surgery.
Source: Lisa Williamson
In both the developed and developing world, the uptake of MIGS is slowly growing, although it is still far from meeting the potential demand, and there are challenges and barriers to overcome.
“To offer MIGS and have good outcomes, a surgeon needs to have the knowledge of the angle of the eye, surgical skills and access to surgical tools. And upstream, they need to have equipment to detect and diagnose the cases,” Susan MacDonald, MD, said.
MacDonald is an associate professor at Tufts University School of Medicine and president of Eye Corps, a nonprofit dedicated to the prevention of blindness in sub-Saharan Africa.
Craig J. Chaya, MD, clinical associate professor at John A. Moran Eye Center and Moran’s division chief of global ophthalmology, said that MIGS companies are actively supporting Moran’s global fellowship program and training missions aimed at forming surgeons in developing nations.
“We have seen an interest from industry to continue to engage and talk about how we could make these technologies more accessible and sustainable over the long haul for these patients,” he said.
However, MIGS penetration will be largely policy-driven.
“We may have to show sovereign nations and their health ministers that allocation for certain services needs to be increased, and it will save the system money to invest in new technologies rather than maintaining the current status quo of just investing in medications,” he said.
Surgical training in sub-Saharan Africa
“I am in Tanzania half of my year, and I am seeing so many people, young people, absolutely blind from glaucoma,” MacDonald said.
About 70% of the population live in rural areas with no access to eye care. Glaucoma medications are scarcely available and too expensive, and adherence is a major challenge.
“The cost of glaucoma drops is about between 10,000 to 40,000 shillings per month — that is over 25% to 30% of the average family income. An unsustainable cost for people who are trying to figure out how to put food on the table,” she said.
Eye Corps has started a partnership with the leading ophthalmology residency programs in Tanzania to identify unmet needs and design supplemental educational resources. Eye Corps funded the renovation of space for a wet lab for surgical training that formally opened in February. Glaucoma surgery will be part of the curriculum, with the hope that MIGS will be part of the program.
“We need industry support to help develop our surgical training program. A year and half ago, we began identifying that gonioscopy was not being taught. Keeler donated the gonio lenses, and we started an online lecture series about gonioscopy because prior to this donation we had few lenses, and it was hard to have organized gonioscopy training. And remember, in order to perform gonioscopy, we need slit lamps, and we are lucky to have Darcy Wolsey, MD, who donated four slit lamps. This November, we had our first in-person gonioscopy training session. My colleagues David Crandall, Jane Durcan and Roger Furlong led the gonioscopy session with the residents in the clinic. We are building awareness of the different types of glaucoma, but we are struggling with equipment and teaching tools. But the only path forward for surgical treatment is with the residents and the faculty members being comfortable with the angle,” MacDonald said.
Last year, Moran’s Global Outreach Division also instituted a glaucoma fellowship in Tanzania, and three fellows are currently trained there by former alumni and friends of Moran.
“We are not training fellows only in the older techniques that are traditionally used by nonspecialists. We are offering them a wide array of different techniques, which include MIGS,” Chaya said. “Moran’s faculty members train them in-country so that these fellows can continue to be a part of their department and to build their practices there. In addition, in their training program, they take care of the types of patients that they will be seeing long term. It is also less disruptive to their family life, as they don’t have to go abroad for 1 to 2 years for their training.”
The training program is mainly focusing on angle-based surgeries, including suture gonioscopy-assisted transluminal trabeculotomy (GATT), bent ab interno needle goniectomy (BANG) and goniotomy with other tools such as the Kahook Dual Blade (KDB, New World Medical). This is followed by bypass stent surgery with the iStent (Glaukos) and Hydrus (Alcon) and viscocanalostomy. A laser for selective laser trabeculoplasty is also available and part of the training.
Beyond training
“We haven’t looked beyond the training period yet. Over time, there may be constraints on the system, in terms of finance and availability of certain technologies, but our hope is, as the industry sees the success of training subspecialists around the world, that there will be an interest in investment in local markets,” Chaya said.
Diagnosing glaucoma earlier is another priority and unmet need in Tanzania and sub-Saharan Africa as a whole.
“With most of the doctors in an urban setting and most of the population in a rural setting, that’s going to be the next challenge,” MacDonald said. “Our teaching focuses on the nerve because we do not have OCT or perimetry. We are looking at AI technologies such as Eyenuk to help us screen and diagnose patients earlier in the disease process and then cluster them so that we can have angle surgery or laser surgery done for those patients.”
She strongly believes that surgical treatment needs to be the future for glaucoma in sub-Saharan Africa.
“Nonadherence to glaucoma medications is a problem throughout the world. Patients forget to use their drops or run out of medicine, and in a low resource setting, the glaucoma drops are unaffordable. The selection of drugs is very limited. There is one beta-blocker and latanoprost, and they are expensive,” she said.
MIGS making inroads in India
“MIGS has broadened our thinking capacity of offering surgical options to patients,” Swati Upadhyaya, MD, said. “Before that, we had tunnel vision: trab or no trab. We didn’t have anything else, and it was either combined phaco-trab or trab alone.”
Upadhyaya is a glaucoma consultant at Aravind Eye Hospital in Pondicherry, India, and has been performing MIGS since 2019. Recently, she started a new surgical skills transfer course at Aravind with dry lab and wet lab training on intraoperative gonioscopy and MIGS for 25 participants. Previously, she was involved in organizing several 1-day CME conferences using 3D-recorded GATT, BANG, KDB, iStent and iStent inject surgeries and a seminar with live 3D surgery with the local glaucoma association.
“Also in our national conferences, like the Glaucoma Society of India conference and the All India Ophthalmological Society conference, we now have dedicated sessions, dry and wet labs for MIGS, and several webinars,” she said.
Thanks to these initiatives, the number of glaucoma surgeons in India who are learning MIGS is steadily growing.
“If you take the Glaucoma Society of India, there are around 700 to 800 people attending, and I would vouch for around 250 of them doing MIGS now. Previously, it was only 50; before that, it was only 10. ... In addition, several cataract surgeons are doing iStent or iStent inject,” Upadhyaya said.
MIGS has made small but definitive inroads in India in the last few years, albeit a little slow and a bit late, according to Vanita Pathak-Ray, MD, director of glaucoma services at the Centre for Sight in Hyderabad, India.
Innovation has always had to face and overcome resistance to change. However, since stents were invented and introduced for ischemic heart disease, as well as neuroradiological coiling for aneurysm in the brain, many open-heart and open-skull surgeries could be avoided. In ophthalmology, even phaco encountered resistance because of the extra cost of the technology.
“Going more and more minimal is the way forward. There is no doubt,” she said.
In her practice, Pathak-Ray offers MIGS to every patient with mild to moderate glaucoma, especially when undergoing cataract surgery.
“It is an opportunity that should not be missed, and I feel very strongly about it, even if they are on just one drug,” she said. She has done MIGS stand-alone also in uncontrolled glaucoma.
Glaucoma medications are not gentle on the eye, and more than 50% of her patients present with ocular surface disease of varying degrees. The higher the number of medications, the greater the risk.
“MIGS leads to very quick visual rehabilitation and much fewer postoperative visits, which patients like, especially if they’re traveling some distance. And it avoids the side effects of medications,” Pathak-Ray said.
In urban settings, some patients are insured, and insurance covers the cost of iStent procedures.
“To those who are not insured, I offer KDB goniectomy, the cost of which is constantly being revised downward, or even BANG. I don’t do GATT in adults per se, as there are many more effective and safe options available without ripping 360° of the trabecular meshwork,” Pathak-Ray said.
“I have done only four iStent inject because most patients here don’t have insurance and cannot afford such a high price. But BANG and GATT are really cost-effective,” Upadhyaya said.
Cost, investments and collaborative efforts
Studies have shown the cost-effectiveness of MIGS in developed countries, where expensive, preservative-free medications are used. In the developing world, where most patients are treated with cheaper generic medications, other factors come into play, such as the high prevalence of vision loss and lost ability to work due to noncompliance or poor access to medical treatment.
“In developing countries, we have to evaluate cost-effectiveness from a more complex perspective. For example, there have been studies in South America that have shown that MIGS can be cost-effective in those countries because it preserves vision,” Chelvin C.A. Sng, MD, glaucoma consultant and professor at the National University of Singapore, said.
Sng is the first author of a chapter on the globalization of MIGS, asserting that despite the many economic, logistic, training, legal and regulatory challenges, “the permeation of MIGS devices internationally is an inevitable reality,” and “glaucoma patients worldwide stand to gain from increased access to MIGS devices.”
“Data are compelling. In the HORIZON study, 73% of patients implanted with the Hydrus microstent in combination with cataract surgery were medication-free over 5 years compared with 48% in the cataract surgery-alone arm,” she said.
In the developing world, she said, a lot of the problem is regulatory approval, which limits access to devices such as Hydrus and iStent. Cost is also a barrier. Companies should proactively engage with policymakers to develop preventive strategies for glaucoma-related blindness.
“Companies need to invest more in the globalization of MIGS, exploring different business models. In countries where the potential surgical volumes are the highest, reducing the cost of MIGS devices would increase the sales and open up new profitable markets,” Sng said.
In doing so, they would also pursue an ethical and humanitarian greater ideal: saving people’s sight.
“What we are hoping to do is promote a collaborative process between all stakeholders, patients, local communities, health ministries and industry for an equitable distribution of technology,” Chaya said.
A great example of this is what happened with the Baerveldt glaucoma implant (Johnson & Johnson Vision). George Baerveldt made the intellectual property of his design available to Aurolab to produce a low-cost version in India.
“That’s an example of how industry, policymakers, inventors and innovators moved together for the common purpose of making a technology available in a context where it was desperately needed. My hope is that industry around the world will understand that there should be a portion of their mission statement focused on countries that have a disproportionate amount of glaucoma burden,” Chaya said.
MIGS in angle-closure and advanced glaucoma
Extending the use of MIGS to angle-closure glaucoma would meet the needs of Asian countries, where this type of glaucoma is highly prevalent.
“We need to do more studies to show that MIGS is effective in angle-closure glaucoma. Personally, I’ve used a lot of MIGS devices off label for angle-closure glaucoma in combination with cataract surgery, and they have worked very well in this context for many patients,” Sng said. “We need more data on this. In Singapore, the insurance companies pay for off-label devices, but this may not be in other countries.”
“I do a lot of endoscopic cyclophotocoagulation (ECP) in angle closure. It is not catching on in India because of the high cost of the machine, but it is an effective minimally invasive procedure in angle closure. I can vouch for it. I find such fantastic results, with 70% to 75% of patients off medications. It is just absolutely stupendous,” Pathak-Ray said.
Anecdotal evidence suggests that in eyes that have not been treated with medications, MIGS can be effective also at the more advanced stages of glaucoma. This is the characteristic presentation of a large percentage of the population in rural areas, where glaucoma is not diagnosed until vision is heavily compromised.
“In the U.S., where advanced-glaucoma patients have typically been on drops for many years, we do have some data to suggest that MIGS does not do well. However, that may be different for patients who present with advanced stages but have never received any type of treatment. I have heard from colleagues that these patients seem to do much better than we previously thought,” Chaya said.
For angle-closure glaucoma, combining phaco with goniosynechialysis and either BANG or KDB is being tried at Aravind, Upadhyaya said.
“For advanced glaucoma, I prefer to do phaco with goniosynechialysis with additional KDB or BANG depending upon financial affordability,” she said. “However, long-term results are yet to be analyzed.”
Pathak-Ray combines two MIGS in advanced glaucoma. She restricts the inflow by doing ECP and enhances the outflow by performing an outflow procedure in the trabecular meshwork. She calls it “combined” inflow-outflow MIGS.
“It could be iStent, or it could be KDB combined with ECP. This is something that has helped me to reduce the number of trabs and the morbidity related to it. And believe me, the results are absolutely amazing. I am able to dramatically reduce the number of medications without having to put the patients through the postop manipulations of trabeculectomy and its complications,” she said.
Many patients from Telangana and Andhra Pradesh in India, and also from other areas, national and international, seek her help for this type of intervention.
Strategies for early detection
The greatest impediment to widespread deployment of MIGS throughout the world is early detection, according to Chaya. A lot has been invested in different techniques and tools, but the diagnostic side has lagged behind. However, new opportunities are opening up with the use of AI and teleophthalmology.
“I am excited about how this is going to change the entire landscape for glaucoma. By identifying patients earlier, we can reduce the impact on the disease over their lifetime,” he said.
Early detection should also include genetic testing and newer tests that could detect biomarkers for risk stratification.
“Currently, the way we diagnose glaucoma is through a battery of tests, and that’s not always practical in a health care system with limited resources,” Chaya said. “We are not there yet, but it would be aspirational for us to move in that direction to identify patients who at a high risk of progression and develop data sets that allow us to use decision-support tools to really harness that technology to earlier diagnose patients.”
As part of its community outreach programs, Aravind regularly organizes screening camps for glaucoma and diabetic retinopathy.
“We use fundus cameras to take photographs of the optic disc, and an ophthalmologist onsite selects the patients who need to be referred to a higher level of care. At the base hospital, we perform family screening for all our glaucoma patients, inviting their relatives to come and get themselves checked. We also do opportunistic screening: When the patient comes with an attendant, we check the attendant there and then on the same day,” Upadhyaya said.
In addition, satellite vision centers associated with the base hospital have been set up as permanent facilities to provide primary eye care services to semirural and rural communities.
“We have started using AI in the vision centers and have performed a study using the Remidio smartphone-based fundus camera that has offline AI for glaucoma detection. Data analysis has shown that sensitivity and specificity for glaucoma detection are very high, more than 85%. We are doing now another study with Liverpool John Moores University where they are refining the AI software based on our fundus images,” she said.
Screening programs and diagnostic identification are crucial for timely treatment planning, but treatment availability is also a prerequisite for worthwhile screening and diagnostic testing.
“My husband has a nonprofit organization, and we regularly reach out to medically underserved communities. We screen the population, we pick up glaucoma, but then what happens after that? I know that those patients won’t use the eye drops we tell them to use or won’t buy them, and they will go blind,” Sng said. “So, I wish that hand in hand with this early detection we can offer them a solution to their glaucoma that is not just using eye drops.”
- References:
- Agrawal P, et al. Ophthalmol Ther. 2018;doi:10.1007/s40123-018-0131-0.
- Bedrood S, et al. Clin Ophthalmol. 2023;doi:10.2147/OPTH.S439457.
- Dean WH, et al. Br J Ophthalmol. 2022;doi:10.1136/bjophthalmol-2020-318049.
- Idriss BR, et al. J Glaucoma. 2021;doi:10.1097/IJG.0000000000001779.
- Jones PR, et al. Ophthalmic Epidemiol. 2020;doi:10.1080/09286586.2019.1661499.
- Murdoch I, et al. PLoS One. 2020;doi:10.1371/journal.pone.0232796.
- Odayappan A, et al. Ophthalmol Glaucoma. 2021;doi:10.1016/j.ogla.2020.11.007.
- Ordóñez JE, et al. Curr Med Res Opin. 2019;doi:10.1080/03007995.2018.1506022.
- Pathak-Ray V. Indian J Ophthalmol. 2022;doi:10.4103/ijo.IJO_465_22.
- Pathak Ray V. Indian J Ophthalmol. 2022;doi:10.4103/ijo.IJO_2226_22.
- Sng CCA, et al. Br J Ophthalmol. 2018;doi:10.1136/bjophthalmol-2018-313170.
- Sng CCA, et al. Globalization of MIGS. In: Sng CCA, et al (eds). Minimally Invasive Glaucoma Surgery. Springer; 2021;doi:10.1007/978-981-15-5632-6_11.
- Sng CCA, et al. J Ophthalmol. 2017;doi:10.1155/2017/9845018.
- Tan NYQ, et al. Curr Opin Ophthalmol. 2020;doi:10.1097/ICU.0000000000000649.
- Upadhyaya S, et al. Eye (Lond). 2022;doi:10.1038/s41433-021-01485-2.
- For more information:
- Craig J. Chaya, MD, of Moran Eye Center, University of Utah, can be reached at craig.chaya@hsc.utah.edu.
- Susan MacDonald, MD, of Tufts University School of Medicine in Massachusetts, can be reached at susan@eyecorps.org.
- Vanita Pathak-Ray, MD, of Centre for Sight in Hyderabad, India, can be reached at vpathakray@gmail.com.
- Chelvin C.A. Sng, MD, of Chelvin Sng Eye Centre in Singapore, can be reached at chelvin@gmail.com.
- Swati Upadhyaya, MD, of Aravind Eye Hospital in Pondicherry, India, can be reached at swati.dr@aravind.org.
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