Cutting Edge Glaucoma - Issue 2

54 • CUTTING EDGE - GLAUCOMA subconjunctival space opposite the incision. Unlike the classical filtering operation, trabeculec- tomy, the procedure with the XEN does not disrupt the conjunctival and subconjunctival tissue. Just like in trabeculectomy, a bleb is created as a result of that new outflow. Pillunat et al . [36] have recommended the application of an antimetabolite such as mitomycin C (MMC) to prevent scar formation. Only one clinical study with the 45-μm XEN gel stent has been published recently. The effectiveness and safety of phacoemulsification combined with the XEN implantation surgery were evaluated in patients with cataract and OAG in a prospective, 12-month follow-up study involving 30 eyes with at least two medications to control IOP. The mean preoperative IOP was 21.2 ± 3.4 mmHg with an average of 3.1 drugs. The study group reported an IOP reduction of 29.3% to an average IOP of 15.0 mmHg after 12 months. This represents an average IOP reduction of 6.2 mmHg [34]. This approach seemed to be particularly effective according to De Gregorio et al . [5] for the management of refractory glaucoma. Discussion Glaucoma will remain a challenge for ophthalmologists and for health care systems everywhere. The number of glaucoma patients globally is expected to rise by 2020 to 65.5 million and by 2025 to 74.6 million, with men appearing to have a 33% higher risk of developing POAG than women [13]. Wide segments of the population suffering from glaucoma are at risk of nonadherence when pharmacologically treated. Those considered most likely to exhibit nonadherence are patients in the age group 50–59 years, the oldest segment of the patient population (80+ years), individu- als who have suffered from glaucoma for a long period of time, and patients with considerable comorbidities, i.e., those suffering from three or more severe diseases in addition to glaucoma [9]. There have been many attempts to improve patient adherence, some of themwith electronical monitoring, which in one observational study induced patients who used to take 75% or fewer of the prescribed doses to become more adherent (somewhat surprisingly, IOP did not correlate with adherence, and was not much different in the still poorly adherent control group and the success- fully ‘‘treated’’ study group) [30]. Just recently, in a population with rather good therapy adher- ence in a society widely known for its high regard for discipline (Japan), a number of factors that influence this overall positive compliance were identified in a nationwide survey. These factors were the size of the clinic, the age and gender of the patients, the amounts and the types of IOP- lowering medications administered topically, the ease of instillation, the preferred number of eye- drops, the preferred frequency of eyedrop instillation, and the patient’s awareness of and level of education about glaucoma [42]. As can easily be seen, none of these factors will come into play once an intraocular drug-delivery system is inserted, which is also the case for recently described factors such as forgetfulness, problems with handling the little bottles, etc. Intraocular sustained-release drug-delivery systems seem to be an expanding market, and a number of companies are active in this field. While some data have been made public at meet- ings, there are only a limited number of publications on this promising technology. However, this approach demands repeated injections not unlike (though definitely less frequent than) those