To model the heat deposited during cataract surgery accurately, we describe here some typical cataract surgery patterns and laser parameters1 used to guide our calculations. The two patterns are the capsulotomy, a 5-mm cylinder that is 400 μm in depth, and a grid-shaped lens segmentation that is 7 mm in width and 3 mm in depth. Since we are primarily concerned with modeling damage in human eyes, the anatomy of the human eye described by the Gullstrand model26 is used in determining the irradiance profile. During capsulotomy, the Gaussian laser beam is focused through water or tissue with similar refractive index with an NA of 0.1 (angle for ) on the anterior lens capsule, which is roughly 20.3 mm above the retina. For the 1030 nm wavelength, this results in a beam radius of on the retina. During the lens segmentation, the focus is as low as 17.3 mm above the retina, which produces the minimum beam radius of 1.3 mm. The submerged human eye is assumed to have approximately 19 diopters of refractive power. Based on ray-tracing, a 5-mm circle in the lens produces a circle on the retina. The lateral spot spacing is 5 μm during the capsulotomy and 10 μm during the lens segmentation, with an average pulse energy of 6 μJ.1,2 The axial spot spacing is 10 μm during the capsulotomy and 20 μm during the lens segmentation. To estimate the repetition rate for scanning beam modeling, we first calculate a conservative safety threshold power by assuming a stationary beam and applying the ANSI standard following the retinal irradiance interpretation done by Delori et al.12,13 For the 1030 nm wavelength and retinal beam radius of 1.3 mm, the maximum permissible power . From the typical pulse energy, pattern size, and spot spacing listed above, we calculate that the total energy is needed to form both capsulotomy and lens segmentation patterns. Assuming that the whole treatment is carried out with the same pulse energy and repetition rate, the fastest laser procedure that is within the ANSI safety limits can be delivered in . For the total energy listed above . The maximum average power is then and for the pulse energy of 6 μJ, the maximum repetition rate is approximately 42 kHz.