## 2 Materials and Methods
### STM Technique  
The experiments were performed with a pump-probe system to conform the STM technique. We used a 9 ns pulsed Nd:YAG (532 nm) laser (Minilite II; Continuum, Inc.) with 25 mJ nominal energy per pulse as the pump laser. The probe laser was a continuous-wave HeNe laser at 632.8 nm (Edmund Optics) with a nominal 10 mW output power; it was used for monitoring the temporal evolution of the cavitation bubbles.  
The STM technique is defined as the modulation of the optical transmission of a CW probe beam generated by the cavitation bubble itself. A cavitation bubble acts as an obstacle, specifically as a negative lens, causing the collimated probe beam to be deflected and scattered (by the bubble contents), thereby affecting the total amount of light that reaches the detector. With this technique, it is possible to capture the whole temporal evolution of a cavitation bubble by applying a single pump pulse; it offers high-resolution oscilloscope traces, which result from the cavitation bubble's growth and its first and subsequent collapses [21; 22; 23].  
The experimental setup used for the present work is shown schematically in Figure 2. A fraction of the energy of the pump beam was monitored with Photodiode 2 (\(\tau_{r}\) = 6.2 \(\upmu\)s, DET10A, Thorlabs), which was previously cross-calibrated against a pyroelectric energy monitor (PM320E, Thorlabs). The pump laser beam was first expanded by a Galilean telescope (\(L_{3}\) and \(L_{4}\), M = 2.5\(\times\)) and, later, it was focused with a 12 mm microprocessing lens. The measured beam quality, \(M\)-squared, for the pump laser was \(M^{2}=6.9\), implying a beam waist radius of 3.2 \(\upmu\)m (\(1/e^{2}\)), which agreed well within the measured beam size found when focused on a glass slide and imaged back onto the calibrated charge-coupled device type camera (CCD-camera, model: PLB776U, Pixelink) using the retro-reflected image relay system, named the equivalent target plane (ETP). With the ETP system, it was possible to determine the precise location of the laser beam's focus on the cornea surface when a new pig eye was placed. Then, the beam waist was displaced about one millimeter (1 mm) below the corneal surface to position it inside the AC.  
The 632.8 nm HeNe probe beam was collimated down (by means of Telescope 2) to a 1.6 mm beam size measured at full width at half maximum (FWHM), allowing a maximum detectable bubble radius of 800 \(\upmu\)m. The probe beam travels through the cornea into the AC of the eye to fill the zone where the cavitation bubble is generated. At the same time, the iris was used as reflective surface (see Figure 3) in order to be able to collect the scattered beam with a lens system, \(L_{5}\) and \(L_{6}\) (10 and 2.54 cm), to send the transmitted light onto the Photodiode 1. This signal was read by a digital oscilloscope (1 GHz DPO4000, Tektronix). The pump laser beam was placed on the optical axis of the eye to take advantage of the maximum volume section within the AC and to have a larger free space for the generation of the cavitation bubbles.  
Figure 1: Action of the pilocarpine for the iris relaxation.  
Every eye used was placed into a holder that exposes the cornea and the optic nerve. To induce the IOP, we used a pressurized-air-regulated system (0 to 300 mmHg) which was in line with a manometer (PDMM01, Pyle) and a needle through a 'Y' adapter. The needle was inserted into the vitreous chambers of the eyes through the optic nerve.