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EW GLAUCOMA 62 October 2018 Presentation spotlight by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer Recognizing the signs of refractory glaucoma and how to manage it R efractory glaucoma is defined as uncontrolled intraocular pressure with evidence of optic nerve and/or visual field deterioration despite maximally tolerated topical and/or systemic anti-glaucoma medications, failed surgical treatment or a combination of surgery and medicines, or a high risk of failure of trabeculectomy. 1 It is a progressive complication associated with almost all types of glaucoma, according to Sidi Mo- hammed Ezzouhairi, MD, Moham- media, Morocco, who spoke about it at the 2018 World Ophthalmology Congress, saying that although the management of refractory glaucoma patients is exceedingly challenging, it is the specialist's job to preserve residual visual function in these patients and never give up. "The criterion that best defines refractory glaucoma is the loss of regulation of IOP and the resultant inability to control optic neurop- athy progression using the maxi- mum tolerated medical therapy," Dr. Ezzouhairi said. "Depending on the systemic status of the patient, the status of the patient's eye, and the grade of glaucoma, one or more criteria are added to this constant one. There are many other clinical cases that make the situation critical and lead to refractory glaucoma. The commonly accepted and used criterion is the failure of traditional filtering surgery." Dr. Ezzouhairi explained that all types of glaucoma can become re- fractory to treatment. However, sev- eral specific case scenarios are more likely to do so and demand the glaucoma specialist's attention, such as primary angle closure glaucoma (PACG), which has been shown statistically to cause more blindness than primary open angle glaucoma (POAG). Also, damaged conjunctiva, for example, by caustic burns and pemphigoid, secondary glaucoma (e.g., neovascular glaucoma, pseu- doexfoliative glaucoma, post-uveitic glaucoma, etc.) can be responsible for a higher incidence of refractory glaucoma than the primary ones. In POAG, the more glaucoma risk factors there are, the greater the like- lihood that the glaucoma will evolve rapidly to refractory glaucoma. Management The best management is always pre- vention. To prevent refractory glau- coma, the ophthalmologist needs to perform a thorough assessment of the patient, which requires moni- toring and management of all types of glaucoma. "These are challenging cases," he said. "A particular aware- ness of the ocular surface during the initial patient evaluation is import- ant, and it should be assessed at each follow-up examination. Patient management should be adapted to the status of the ocular surface. Ocu- lar surface disease increases the rate of unsuccessful filtration surgery." The available options for the management of refractory glaucoma include microinvasive glaucoma sur- gery (MIGS), glaucoma drainage de- vices, ultrasound ciliary plasty, and cyclophotocoagulation laser diode, continuous or micropulse waves. Dr. Ezzouhairi considers con- ventional surgery when maximum tolerated medical therapy and laser become ineffective. Surgery Management of refractory glaucoma Refractory glaucoma in siliconic and buckled eye following vitreoretinal surgery Source: Sidi Mohammed Ezzouhairi, MD should be well prepared, and the follow-up period is equally import- ant to achieve good outcomes. The post-surgery failure rate is closely correlated with the standard of post- operative care. The most well-known glauco- ma drainage devices are the Ahmed (New World Medical, Rancho Cucamonga, California), Baerveldt (Johnson & Johnson Vision, San- ta Ana, California), and Molteno (Katena, Denville, New Jersey). With all three of these devices, the long- term IOP seems to depend on the surface area of the implant, which determines bleb size, tissue response to the implant, and thickness of the fibrous capsule controlling percola- tion of aqueous humor through the bleb wall. 2 "The aim of the glauco- ma drainage devices is to drive the aqueous humor posteriorly, to an area where the scarring is less im- portant," Dr. Ezzouhairi said. The Ahmed device is a valved silicone or polypropylene, single- or double-plated implant made in var- ious sizes. Valved devices offer more immediate IOP control and a lower rate of hypotony. The Baerveldt implant is a non-valved silicone implant, and the Molteno consists of a non-valved polypropylene de- vice, both available in various sizes and number of plates. Non-valved devices are often occluded with a stent or a ligature suture, leaving the postoperative IOP unchanged and requiring the continuation of the medications until the fibrous capsule forms. 2 A study that reviewed the 5-year outcomes of the Ahmed versus Baerveldt implants in refractory patients showed that most of the failures happened in the first 2 years after surgery. However, the reason for failure was different in the two groups; the cause of failure from high IOP was higher in the Ahmed valve group (80% failure in this group) compared to the Baerveldt group (53% failure) (P=.003). The reverse was true as well with the Baerveldt group showing a higher risk for persistent hypotony (47% of failures) compared to the Ahmed group (20% of failures). 3 The success rate of the Ahmed valve decreases by 10% per year, and success after 5 years is below 50%, Dr. Ezzouhairi said. Dr. Ezzouhairi said that al- though some studies that examined the use of sequential glaucoma drainage devices seem to have re- vealed lower success rates, he thinks that the results of the initial implant studies may not be accurately ex- trapolated to additional shunts. Experiencing initial success with a glaucoma drainage device does not necessarily mean that the patient is out of the woods. According to Dr. Ezzouhairi, complications include early or delayed hypotony some- times associated with athalamy, choroidal detachment, and hem- orrhage. There can also be early or delayed ocular hypertension caused by tube obstruction, tube retraction, and an inflammatory scarring mem- brane around the reservoir. Further complications include corneal touch and edema, cataract, and endoph- thalmitis. Some specialists turn to cyclode- struction as a means of alleviating refractory glaucoma. It avoids complications linked to blebs and is easy to perform. The procedure performed in a closed eye meth- od avoids complications linked to blebs such as infection. It's easy to perform, is not time consuming, can