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EW GLAUCOMA 116 September 2015 by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer "For me the new conception of target pressure is to use clinical trial data on risk/benefit to inform choices in similar patients. Now that we have enough data to give a dose/ response curve approach, we can actually know what the risk is at a certain pressure for a given patient," he said. The wrong focus Not all glaucoma specialists would agree. Reay Brown, MD, Atlanta Ophthalmology Associates, thinks that a target IOP should not be the central focus of therapy. "Determin- ing a target pressure for an individ- ual patient is a form of predicting the future and is inherently uncer- tain. Furthermore, imprecise IOP measurements and IOP fluctuations make the notion unreliable. Fluc- tuating diurnal pressures provide only a snapshot of a patient's IOP and may not be representative—es- pecially in cases of non-compliance. On top of that, the technique is imprecise. We measure pressure by a series of indirect measurements. found on average a 14% improve- ment in visual field mean devia- tion. A similar average visual field improvement was reported recently by investigators in the Collaborative Initial Glaucoma Treatment Study (CIGTS). This was not a regression to the mean because it only happened to those people whose peak pres- sures were quite low. Dr. Palmberg's results line up with both the vascular and the mechanical theories of optic nerve damage, which theorize that IOPs near the venous pressure/CSF pressure should be optimal. "It now looks as though the optimal IOP is ≤13 mm Hg, centered around 10 mm Hg, corresponding with venous and CSF pressures. It makes the holy grail of glaucoma management an operation that could get IOPs in that range, while avoiding hypotony or other complications. This may be possible with either the XEN Gel Stent [AqueSys, Aliso Viejo, Calif.] or the InnFocus MicroShunt [Miami], both in FDA trials." Specialists explore the pros and cons of setting a target pressure with mounting clinical evidence P hysicians often say that glaucoma care is a mixture of art and science, requir- ing careful consideration of each patient's distinct problem and a highly individual- ized approach to treatment, in part due to the absence of a dividing line between normal and abnormal IOP. The notion of setting a target pressure is appealing to clinicians because it provides a goal to work toward and a benchmark by which to measure success. Unfortunately, setting a target pressure is not an exact science, and although IOP reduction is known to slow disease progression and is the mainstay of glaucoma treatment, the rules still blur regarding the use of a target IOP as a standard component of care. The lower the target pressure, the better According to Paul F. Palmberg, MD, University of Miami, we have all the evidence we need that target pressures work. "We need to use the data from clinical trials to make informed choices, modified by the actual experience with the patient. The data from clinical trials show a dose/response relationship between the pressure achieved and the risk of progression over the next 5–8 years. The Advanced Glaucoma Interven- tion Study (AGIS) 1 reported a 13% chance of visual field worsening after 8 years in advanced glaucoma patients with a peak IOP under 18 mm Hg and average pressure of 12 mm Hg. Further data evaluation suggests to me a 30% chance of worsening at a mean pressure of 15 mm Hg and a 70% chance of worsening in advanced patients at pressures between 18–20 mm Hg. Not everyone with advanced damage needs to achieve an IOP <15 mm Hg, but one's odds improve," he said. Other trial results also indicate that the lower the IOP, the lower the likelihood of progression. In addi- tion, in his patients with peak pres- sures under 14 mm Hg after 5-FU or MMC trabeculectomy, Dr. Palmberg Target IOP: Do we have enough evidence? A t the 2015 ASCRS•ASOA Sympo- sium & Congress in San Diego this past spring, I attended an EyeWorld symposium titled "Phaco Fundamentals." Ostensibly, this course was intended for beginning cataract surgeons to reinforce what they had just learned during their training years. Yet there I was, more than 5 years out from the end of my fellowship, learning a tremendous amount of incredibly useful information that I had either forgotten or never learned adequately in the first place. Based on the audience response system (ARS) questions at the session, the majority of the attendees at the session were even more senior than me. This got me thinking about how the "fundamentals" concept may represent an unmet need for ophthalmologists who are many years out from their training. We reach a point in our careers where it is embarrassing to admit that we have forgot- ten the basics, and yet it is hard to find a good, succinct resource that will (discretely) reteach us those basics. From this, the idea of a "Glaucoma fundamentals" column in EyeWorld was born. In each column, we will address a common glaucoma question that comprehensive ophthalmologists face numerous times per week in their practices, such as: "I see a disk hemorrhage—now what?" "What do I do if my glaucoma patient is progressing at low intraocular pressures?" "Which patients with ocular hypertension should be treated?" Our intent is to provide answers that are practical and usable in your daily practice. For our first column, we tackle the questions: "Should I set a target IOP for my glaucoma patients? Why (or why not) and how?" To answer this question, we sought the opinions of 3 world-renowned glaucoma specialists: Paul F. Palmberg, MD, Reay Brown, MD, and Harry A. Quigley, MD. We hope EyeWorld readers find "Glaucoma fundamentals" helpful. We welcome your feedback and ideas for future columns. Husam Ansari, MD, PhD, Glaucoma fundamentals editor The idea of setting a target pressure can be appealing to some physicians because it provides a goal to work toward and a benchmark by which to measure success. However, setting a target pressure is not an exact science, and other physicians prefer to base treatment decisions on clinical factors that are more conclusive. Glaucoma fundamentals T OO H I GH T O O H I G H JUST RIGHT T O O H I G H T O O H I G H

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