What are the limits on myopia for a pre-eye refraction surgery for a class 1 medical certificate?
It looks like there are no limits for your pre-surgery eyesight:


  Flight crew having undergone refractive surgery will be considered for
  medical fitness for flying on a case-to-case basis. Such cases will be
  examined only after a minimum period of six months after the
  procedure. Medical fitness for initial issue of licence may also be
  considered for such cases, if the visual requirements for the license
  category are met with normal corneal topography, no post surgical
  complications like corneal opacity interfering with vision and
  unstable refraction.


That makes sense: LASIK physically changes your eyes, so whatever your values were before the surgery are completely irrelevant after it. The general class I eyesight requirements in India are taken from ICAO Annex 1, which isn't freely available online. However, ICAO's Manual of Civil Aviation Medicine says:


  Distant visual acuity with or without correction shall be 6/9 or
  better in each eye separately, and binocular visual acuity shall be
  6/6 or better. No limits apply to uncorrected visual acuity.