A non-invasive apparatus and method for treating open angle glaucoma in a human eye comprises thermally ablating a targeted region of the trabecular meshwork of a human eye by irradiating the region with a beam of pulsed laser radiation. The beam of pulsed radiation has a wavelength between 350 and 1300 nanometers, energy of 10 to 500 millijoules per pulse, and pulse duration of 0.1 to 50 microseconds. The beam is non-invasively delivered gonioscopically through the cornea onto a targeted region of the trabecular meshwork. The targeted region of the trabecular meshwork is illuminated at a spot size of between 50 and 300 microns in diameter.