Lasers are widely used in medicine. Applications of laser in ART have evolved in recent years and apart from use in research, clinical use is growing as technology and instrumentation are simplifying laser availability and practical utility.
Lasers may be of contact type or non contact type. In the latter, laser energy at the focal point is absorbed by the tissue water and macromolecules resulting in disruption of the matrix and ablation. The diode non contact infrared lasers appear to be most appropriate for zona-cutting applications.52 Indium-gallium-arsenic-phosphorus laser is popular with a wavelength of 1.48 microns being rapid, safe and effective.
The zona pellucida post sperm entry undergoes a series of mechanical and chemical changes in order to prevent polyspermy and protect the developing embryo. In some cases the zona becomes extremely hard and impairs embryo hatching. A mean zona thickness of 18 microm or more is considered significant. Lysine is important and deficiencies in action or function are important for failure to hatch. This deficiency could arise as a result of in vitro culture conditions. Zona thinning or drilling have shown improvement in implantation rates in selected cases wherein it optimizes the implantation window and promotes earlier implantation. |
