The other category is intraocular contact lens implantation, which can be understood as installing a special contact lens into the eye, also called ICL implantation surgery. Although laser surgery is divided into three more types, the basic principle is the same. The myopic glasses we usually wear are actually a concave lens, and the principle of laser surgery is to artificially cut off a convex lens on the cornea, which is equivalent to creating a "concave lens", that is to say, cutting off the shape of a small eyeglass lens on the eye.
Semi-femtosecond
The femtosecond laser is used to make a corneal flap and then the excimer laser is used to cut the cornea. The difference between the semi-femtosecond and excimer lasers is the difference in the way the flap is made; the semi-femtosecond uses a femtosecond laser while the excimer uses a laminar knife.
Full Femtosecond
Full femtosecond laser surgery does not require the creation of a corneal flap, but rather, the stroma layer of the cornea is blasted with laser light at different depths on two successive occasions to form a stromal lens, which is then removed through a micro-incision of 3 to 4 millimeters. Simply put, the full femtosecond laser does not need to lift a window to the cornea, but only needs to be removed after the lens is made in the cornea.
ICL IOL Implantation
This is a completely different operation from laser surgery, in which the surgeon restores the patient's vision by implanting an IOL into the eye. It can be understood that the doctor creates a small lens and then places it inside the patient's eye.