Education Committee Highlights WGC-2019 – part 14

The Education Committee carefully selects presentations from the WGC-2019 for your benefit. This month Rajul Parikh introduces the sessions: Spotlight on Glaucoma in Africa and The glaucoma surgery armamentarium – what’s in our 2019 bag of tricks.

Spotlight on Glaucoma in Africa

As of 2016, the total population of Africa is estimated at 1.225 billion, representing 17% of the world’s population. According to UN estimates, the population of Africa may reach 2.5 billion by 2050 (about 26% of the world’s total) and nearly 4.5 billion by 2100 (about 40% of the world’s total). Only 1.3% of the world’s health workers care for people who experience 25% of the global disease burden, making severe imbalance in health care system in Africa. Africa is the poorest region in the world: 50% of the population lives on less than 1 $/ day. Millions of people don’t have access to health care in general and less than 25% currently have regular access to eye care services. In such a context and gloomy poverty, the prime concern for many is survival, and seeking health care is a decision of last resort. In this “Spotlight in Africa in Africa”, various speakers have given an outline about glaucoma-related issues in the African continent.

Kgaogelo Legodi discusses the visual impairment statistics in the African continent. In Africa, glaucoma accounts for 15% of blindness and it is the region with the highest prevalence of blindness relative to other regions worldwide. He discusses about LEGACY project which is aimed to improve the health care facility in Africa.  Olusola Olawoye discusses the magnitude and burden of the glaucoma problem in Africa. The prevalence of glaucoma in East, Central, and Southern Africa can be conservatively estimated to be 10,000 people for every 1 million population. This prevalence may be higher in West Africa. The annual incidence of glaucoma can be conservatively estimated to be 400 new cases for every 1 million population. Glaucoma is the second leading cause of blindness after cataract, responsible for up to 30% of blindness. With such high prevalence and blindness, the case detection of glaucoma must be carried out at both the primary and secondary levels. Glaucoma and glaucoma-related blindness are more common in the African origin population compared to the Caucasian population. Blindness due to glaucoma has been found to be four to five times more common among people of African descent (PAD) compared with people of European descent. Glaucoma affects over 4% of the PAD adult population, compared with 2% in those of European ancestry (and 16% in subjects over 70 years compared with 6%). Susie Williams discusses the difference in glaucoma manifestation in African populations compared to other populations. She mentioned that POAG is the most common type of glaucoma; more severe disease with poor prognosis compared to other populations. Dan Kiage discusses Challenges and Opportunities of Medical and Surgical Management. He mentioned that “Glaucoma management remains a major challenge in Africa due to the high prevalence of the disease, poverty, a shortage of ophthalmologists, and insufficient infrastructure.”  Trabeculectomy has remained the primary surgical approach due to its markedly low cost and high efficacy. The use of drainage devices is hampered by their cost. One promising low-cost alternative is the non valved Aurolab Aqueous Drainage Implant (Aurolab), but this device has not yet been introduced in Africa. Tony Realini discussed the role of Selective Laser Trabeculoplasty in the African Population. The use of selective laser trabeculoplasty (SLT) is growing in Africa, and the initial reports are encouraging. Several studies are underway to determine the indications and efficacy of SLT in this setting and in the future, we will have cleat guideline about using SLT in this kind of setting. In my opinion, even if the SLT lasers can be accessed and maintained, we still face the challenge of whether the procedure will be singularly effective in the majority of relatively young glaucoma patients who present late and with very high IOP.  Philip Phatudi discussed “My journey – reducing blindness from glaucoma in South Africa”.

Essentially, there are 5 main Challenges related to early detection, diagnosis, and management of glaucoma in the Middle East-Africa region:

  1. Adequate Infrastructure: Need to ensure that training institutions, tertiary eye units, and all high-volume eye units are accordingly equipped
  2. Affordability & availability of Anti-Glaucoma Drugs: Need to set a national strategy for their procurement and distribution
  3. Availability of skilled personnel: Need to Identify, support, re-train and recruit personnel. Identify & support training institutions and the deployment of eye care teams from primary to tertiary levels
  4. Patients continuous education Need to develop a culturally sensitive IEC strategy -Target patients at risk
  5. The need for National Glaucoma Guidelines/Policies

This would require at least 2 actions:

  1. Update the glaucoma strategy section in existing national plans
  2. Set up an HRD sub-group to oversee their development and implementation

Watch the presentations

The glaucoma surgery armamentarium – what’s in our 2019 bag of tricks

In “The glaucoma surgery armamentarium – what’s in our 2019 bag of tricks” session various internationally renowned glaucoma specialist talks about trick and tips about various glaucoma surgeries from “Gold Standard” Trabeculectomy to newer MIGS.

Mark Walland in “Keep it simple: phaco alone” talks about the role of phacoemcification in glaucoma management. He explains the biological plausibility of cataract extraction, especially in PACD (Primarybangle Closure Disease) patients. Earlier removal of cataracts seems to be a reasonable option in PACD, but at the present time there is no published data to guide the use of clear lens extraction for this condition. We have combined data from trials addressing cataract extraction in PACD and estimates of the rate of the events we hope to prevent with lens extraction to provide guidelines for the use of CLE. In APAC, once the attack has been aborted, clear lens extraction can be considered when conventional treatment does not stabilize the eye following an acute attack. Acute intervention with lens extraction as primary treatment in APAC remains less appealing except in resistant cases due to potential for surgical complications that can be avoided by conventional treatment and an elective approach to the lens if later indicated. The role of CLE in fellow eyes is best restricted to those who continue to have symptoms, or a recurrent attack despite the use of laser iridotomy, laser iridoplasty as well as medications. In PACS, there is currently no role for CLE. For PAC, clear lens extraction is only considered if conventional treatment (LPI, iridoplasty and medications) does not control the IOP and a significant portion of the angle can be opened on indentation gonioscopy. There are no data to support combining CLE with goniosynechialysis. Medically controlled PACG without cataract does not require intervention. CLE is considered in uncontrolled PACG despite conventional laser and medical treatment especially if ‘significant’ angle opening is possible on indentation gonioscopy. A decision is still required in PACG as to whether lens extraction should be combined with trabeculectomy or whether trabeculectomy alone is preferred. There are currently only one randomized controlled trials supporting the use of CLE as a treatment for PACG. A benefit from the procedure is biologically plausible and extrapolation from existing randomized trials to a few specific situations may be possible. Any potential benefit must be carefully weighed against the risks of intervention.

Matthew Schlenker talked about various MIGS procedures. He mainly talked about MIGS related to trabecular bypass. Five-year post-surgery data from the COMPASS-XT long-term safety study showed that the CyPass Micro-Stent group experienced statistically significant endothelial cell loss compared to the group who underwent cataract surgery alone. Although MIGS seem efficient in the reduction of the IOP and glaucoma medication and show a good safety profile, this evidence is mainly derived from non-comparative studies and further, good quality RCTs are warranted. Ingeborg Stalmans talks about microshunt “Xen implant”. She described the technique in great detail. A non-randomized 2 year published data showed, mean IOP reduction and medication count reduction from baseline were − 6.2 (4.9) mmHg and − 1.5 (1.4) at month 24 months. The clinical success rate was 67.6% at 12 months and 65.8% at 24 months. Overall, 51.1 (12 months) and 44.7% (24 months) of eyes were medication-free. A significant percentage of patients do require bleb needling.

Dr. Tanuj Dada talks about the “Gold Standard” surgery for glaucoma: trabeculectomy. He talks about Trabeculectomy without MMC, with MMC, and with Ologen implants. He discusses how to improve the success of surgery by identifying the risk factors. He also discussed adding sclerectomy along with trabeculectomy to improve the success rate: however, we do not have long term data of this procedure comparing to trabeculectomy. He showed various studies showing that trabeculectomy MMC has better success rate compared to trabeculectomy with ologen.

Gordana Sunaric-Megevand discussed non-penetrating glaucoma surgeries. Meta-analysis comparing trabeculectomy versus viscocanalostomy showed a much higher success rate with trabeculectomy. At 2 years, the mean intraocular pressure difference was 3.42 mm Hg (1.80, 5.03). Trabeculectomy was found to have a significantly better pressure-lowering outcome (P<0.0001). Relative risk of adverse events such as perforation of Descemet membrane, hypotony, hyphema, shallow anterior chamber, and cataract formation, were found to be 7.72 (2.37, 25.12), 0.29 (0.15, 0.58), 0.50 (0.30, 0.84), 0.19 (0.08, 0.45), and 0.31 (0.15, 0.64), respectively. Viscocanalostomy had a significantly higher relative risk of intraoperative perforation of Descemet membrane, whereas trabeculectomy had significantly more postoperative adverse events (P≤0.008).

Sheng Lim discussed the role of glaucoma drainage devices in management. He discussed the surgical technique, especially how to make needle track if we are doing patch graft less surgery. He discussed the comparative efficacy between AGV versus Baerveldt. The cumulative failure rate at 5 years was 49% in the Ahmed group and 37% in the Baerveldt group (P = .007). High IOP was the most common reason for failure in both groups, and de novo glaucoma surgery was required in 16% of the Ahmed group and 8% of the Baerveldt group (P = .006). Failure owing to hypotony occurred in 0.4% of the Ahmed group and 4.5% of the Baerveldt group (P = .002). Visual outcomes were similar between groups (P = .90). The Baerveldt group had a lower failure rate, a lower rate of de novo glaucoma surgery, and a lower mean IOP on fewer medications than the Ahmed group. Baerveldt implantation carried a higher risk of hypotony. He mentioned that the complication with Baerveldt is higher in NVG (neovascular glaucoma) and in this group of patients, he would use Ahmed glaucoma Valve. PTVT study showed that the cumulative probability of failure in the trabeculectomy group lower than the tube group.

Eugenio J Maul discussed cyclodestructive procedures, a procedure we usually keep as the last option in glaucoma management.

Watch the presentations