**1. Introduction**

In the field of ophthalmology, laser technology is used in many basic and clinical disciplines and specialties. It has played an important role in promoting the development of ophthal‐ mology. Advancements in technology have allowed measurable improvements in the surgical safety, efficacy, speed, and versatility of the laser, creating more operation methods to treat eye diseases, especially corneal refractive surgery. Because myopia is one of the most prevalent

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ocular disorders, and high myopia may result in comorbidities associated with significantly increased risks of severe and irreversible loss of vision, it is always an important topic of research worldwide. Laser technology, including the excimer laser and the femtosecond laser, has brought an era of laser corneal refractive surgery. According to the location of ablation, corneal refractive surgery can be divided into two types: laser corneal surface refractive surgery and laser corneal lamellar refractive surgery. Because of the increasing numbers of applications in ophthalmology and their successful implementations, ophthalmic use of laser technology is expected to continue flourishing.

The aim of this chapter is to review the evolution of laser technology in refractive and other ophthalmologic surgeries, mainly focusing on the characteristics of two types of lasers and their applications: the excimer laser applied in laser corneal surface refractive surgery and presbyopia surgery and the femtosecond laser applied in laser corneal lamellar refractive surgery and other ophthalmologic surgeries.
