Regarding the criteria for myopia in Government Jobs.

In case, you clear out your written and oral test, your final selection would depend upon your medical fitness issued by the medical team of the company.
The medical board would examine your heart, lungs, height, weight, hydroxyl and other physical conditions. The minimum height and weight for being medically fit is 5 ft 3" and 45 kilos respectively.
In respect of fitness of eye - sight, the candidates should not suffer from squint and colour blindness. Check the condition of eye - sight from its medical booklet and in most of the companies follow +/- 4.0 D for final eye sight fitness.
Once you confirm their status of eye sight vision, go in for LASIK Surgery by an efficient surgeon so that your vision matches as included in their medical board.

Generally, PSUs or Govt departments will have the requirement of vision mentioned under the general condition alone with the application form and you can find it there. The eligibility would be mentioned in terms of something like 6/6 or 6/9 or 6/12 etc. Most of the times the eligibility is 6/18 in each eye or 6/12 in one eye and 6/24 in the other eye without glasses or 6/9 with glasses in both eyes. This in terms of power translates to -4.0 to -5.0 Dioptre. It may differ from PSU to PSU depending on their work environment.

You can go to an eye test place and find out it by looking at the chart which is displayed there. This chart has bigger letters on the top and then they gradually become smaller on the following lines. The doctor or optometry assistant would ask you to read it from a distance of 6 meters. For example, if you can not read the last 2 lines then your eye sight is 6/9 but if you can not read the last 3 lines then it is 6/12. After that they would issue you a report mentioning the value in diopter (+ or -) as well as in form of 6/6 or whatever it is.

In case your eye sight has departure from the eligibility conditions then you might have to undergo the Lasik surgery to correct it. Many people go for that option.

Public Sector undertakings or government institutions or any other government organisation, once the selection process is carried out before issuing the final appointment letter the candidate has to undergo a physical fitness test by the doctor's panel.

After completing my written test and oral test for a job in Naval Dock Yard, Visakhapatnam, I was asked to undergo a medical fitness certificate. In that, they found that my height is less than what it was specified. So I was rejected. SImilarly for these posts also there will be specific norms. You should match those norms.

Generally, +/- 4.0 D will be the minimum and maximum allowed eyesight limits. What I suggest is that you can go to an ophthalmologist and get your eyesight tested. If it is not in the mentioned limits you take the suggestion of the doctor and you can undergo Lasik Surgery for the correction of the eyesight.