In some cases, after ICSI the embryos that develop often have a thick cell wall. This can interfere with process of implantation as it impedes a process called hatching in the embryos. In order to prevent this from happening, small holes need to be drilled in the cell wall of the embryos with the help of a laser. This makes the cell wall adequately thin and allows hatching to take place appropriately.
This improves the chances of implantation in the patient. However it is interesting to note that only a minority of patients undergoing ivf or icsi treatment require assisted laser hatching. Empirically doing a laser hatching for all patients can be detrimental rather than beneficial.