These lines are the posterior capsule which has found its way into the suction port of the I/A probe. We need to immediately stop the suction and also go into reflux mode. This will cause the peristaltic pump to spin backwards and reflux fluid back into the eye, which will then easily and safely release the posterior capsule.
In most phaco machines, reflux mode is activated by pivoting the foot and pushing against the left button, marked with a red X in the photo above.
Click below to watch a video explaining the use of reflux mode: