A Randomized Controlled Trial to Determine the Effect of Inhaled Corticosteroid on Intraocular Pressure in Open-Angle Glaucoma and Ocular Hypertension: The ICOUGH Study.

PURPOSE: The purpose of this study was to determine the risk of a steroid pressure response from inhaled corticosteroids. PATIENTS AND METHODS: This randomized, double-masked, placebo-controlled trial included 22 adults with well-controlled open-angle glaucoma or ocular hypertension. Consenting participants were randomized to a 6-week course of twice-daily fluticasone propionate 250-µg metered-dose inhaler or saline placebo metered-dose inhaler. Biweekly clinic visits included masked Goldmann applanation tonometry and assessment to identify adverse effects. Primary outcome was mean intraocular pressure (IOP) at week 6. Secondary outcomes included IOP elevation of >20% at 2 consecutive visits, adherence, side effects, and logMAR visual acuity. RESULTS: A total of 10 patients in each arm completed the study. There were no statistically significant differences in IOP between groups at baseline (14.3±3.0 and 15.6±3.6 mm Hg in steroid and placebo groups, respectively, P=0.39) or at week 6 (14.7±2.4 and 14.8±3.8 mm Hg in steroid and placebo groups, respectively, P=0.92). Adherence was >80% for all participants. There were no statistically significant differences between groups in any secondary measures. One patient in the steroid group met the secondary end point of >20% elevation in IOP (IOP increased from baseline of 9 to 11 mm Hg at weeks 2 and 4). CONCLUSIONS: We found no clinically significant increase in mean IOP in patients with well-controlled open-angle glaucoma and ocular hypertension after 6 weeks of twice-daily inhaled fluticasone propionate compared with inhaled placebo. No participants exceeded their individualized target IOP. There were no differences in secondary outcomes.

Flow Test to Predict Early Hypotony and Hypertensive Phase After Ahmed Glaucoma Valve (AGV) Surgical Implantation.

PURPOSE: To assess the validity of a preimplantation flow test to predict early hypotony [intraocular pressure (IOP)≤5 mm Hg on 2 consecutive visits and hypertensive phase (HP) (IOP>21 mm Hg) after Ahmed Glaucoma Valve (AGV) implantation. PATIENTS AND METHODS: Prospective interventional study on patients receiving an AGV. A preimplantation flow test using a gravity-driven reservoir and an open manometer was performed on all AGVs. Opening pressure (OP) and closing pressure (CP) were defined as the pressure at which fluid was seen to flow or stop flowing through the AGV, respectively. OP and CP were measured twice per AGV. Patients were followed for 12 weeks. RESULTS: In total, 20 eyes from 19 patients were enrolled. At 12 weeks the mean IOP decreased from 29.2±9.1 to 16.8±5.2 mm Hg (P<0.01). The mean AGV OP was 17.5±5.4 mm Hg and the mean CP was 6.7±2.3 mm Hg. Early (within 2 wk postoperative) HP occurred in 37% and hypotony in 16% of cases. An 18 mm Hg cutoff for the OP gave a sensitivity of 0.71, specificity of 0.83, positive predictive value of 0.71, and negative predictive value of 0.83 for predicting an early HP. A 7 mm Hg cutoff for the CP yielded a sensitivity of 1.0, specificity of 0.38, positive predictive value of 0.23, and negative predictive value of 1.0 for predicting hypotony. CONCLUSIONS: Preoperative OP and CP may predict early hypotony or HP and may be used as a guide as to which AGV valves to discard before implantation surgery.

Assessment of closing pressure in silicone Ahmed FP7 glaucoma valves.

PURPOSE: To measure closing pressure in a series of new Model FP7 silicone Ahmed Glaucoma Valves (AGVs), using an in vitro gravity-driven system, in which closing pressure was measured directly from a dual manometer/pressure reservoir. METHOD: A straight length of tubing served as an open manometer, which connected via a 3-way stopcock to the inlet of the AGV submerged under 1.5 cm of balanced saline solution (BSS). Six AGV were assessed in 5 sequential trials and the mean inlet pressure at 90 minutes was recorded as the closing pressure. After testing, a single valve was primed a second time using greater force and retested. Control trials were performed with a submerged 26-G cannula opening directly into the BSS bath. RESULTS: At 90 minutes, the 6 valves equilibrated at a mean inlet pressure of 7.1 mm Hg, with a range from 1.4 to 13.5 mm Hg. Closing pressures at or less than 5 mm Hg were measured in half (3/6) of the valves tested. The average flow of BSS across the valves in the final 30 minutes was less than 1.5x10(-2) microL/min. In the single valve reperfused under greater pressure, the closing pressure increased. CONCLUSIONS: Model FP7 AGVs, in vitro, exhibit significant variability in closing pressure, with half closing at intraocular pressures considered potentially problematic in clinical situations. The results of the high-pressure perfusion experiment suggest that more research into the priming process is required so a precise description can be developed for surgeons.

Continuous intraocular pressure (IOP) measurement during glaucoma drainage device implantation.

PURPOSE: To measure the effect of the implantation of a glaucoma drainage device on the intraocular pressure (IOP) during the implantation surgery. METHOD: We implanted telemetry devices into 1 eye each of 3 white New Zealand rabbits. Once the telemetry was found to be working and the rabbits had fully recovered from surgery, we implanted a glaucoma drainage device into the same eye while continually monitoring the IOP with the telemetry devices. RESULTS: During surgery IOP was extremely variable, however, extremely high pressures were recorded in association with suturing and viscoelastic injection. DISCUSSION: The fact that pressures are significantly raised during some surgical events should make surgeons aware that manipulations need to be kept as short as possible to prevent further potential damage to glaucomatous optic nerves. There is a possibility of dramatically raising the IOP during surgery, specifically in complicated cases requiring prolonged manipulation and/or forcible deepening of the anterior chamber. In such cases, it may be a good idea to time the duration of manipulations to prevent prolonged episodes of elevated IOP.