To describe a new aqueous outflow model involving a mechanical pump. Laboratory materials include human and monkey eyes; methods include the dissecting microscope, light microscopy, scanning electron microscopy, transmission electron microscopy, and tracer studies. Clinical methods involve human subject slit lamp, gonioscopy, and operating microscope examination. Laboratory evidence demonstrates that aqueous outflow tissues are responsive to intraocular pressure induced deformation. Deformation occurs in response to small pressure gradients. Laboratory evidence also demonstrates the presence of valves discharging aqueous to Schlemm’s canal. The laboratory model predicts pulsatile aqueous discharge in vivo. Clinical in vivo evidence demonstrates pulsatile aqueous flow from the anterior chamber into Schlemm’s canal, from Schlemm’s canal into collector channels, and from Schlemm’s canal into aqueous and episcleral veins, all synchronous with the ocular pulse. Aqueous outflow tissue deformation caused by normal intraocular pressure transients induces pulsatile one-way discharge of aqueous to the vascular system. The model identifies biomechanical coupling of intraocular pressure with aqueous outflow tissue deformation and also sites of high flow capable of inducing shear stress. These mechanotransduction mechanisms, well characterized as a means of controlling pressure and flow in the vascular system, also provide a means of regulatory feedback to control intraocular pressure and aqueous flow.

To provide an update of the short-term results of combined phacoemulsification and trabeculotomy by the internal approach with a follow-up to 21 months. Universities and private practices in the United States. This prospective interventional case series comprised 304 consecutive eyes with open-angle glaucoma and cataract having combined phacoemulsification and trabeculotomy with a Trabectome (NeoMedix Inc.). The Trabectome is designed to open a direct pathway for aqueous to flow from the anterior chamber into Schlemm canal collector channels. Under gonioscopic control, bipolar cautery was applied by a purpose-designed footplate to ablate the trabecular meshwork and inner wall of Schlemm canal. The main outcome measures were intraocular pressure (IOP), glaucoma medication use, and complications. The mean IOP was 20.0 mm Hg+/-6.3 (SD) preoperatively, 14.8+/-3.5 mm Hg at 6 months, and 15.5+/-2.9 mm Hg at 1 year. There was a corresponding drop in glaucoma medications from 2.65+/-1.13 at baseline to 1.76+/-1.25 at 6 months and 1.44+/-1.29 at 1 year. Subsequent secondary glaucoma procedures were performed in 9 patients. The only frequent complication, blood reflux in 239 patients (78.4%), resolved within a few days. Combined phacoemulsification and trabeculotomy by the internal approach using the Trabectome lowered IOP and medication use in the majority of patients. Complications were minimal and comparable to those in an earlier series of Trabectome-only procedures.