Why can you not have had laser eye surgery?

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Hello, I'm currently a train driver and I’m interested in applying to one of your driver roles. I’ve noticed it says no laser eye surgery and I’m wondering for what reason as this excludes me. I’ve currently passed a driver medical to industry standard. Is this unique to first group. I know when laser eye surgery first came out and techniques were new some train companies would reject applicants with eye surgery but since the methods for surgery have improved and become mainstream most companies have dropped the ban on surgery.