Each PSU  has their own medical guidelines. If your low vision disability is in between 40% to 75% then you are eligible for PSU's job. The candidates with normal visions which are corrected by glasses can eligible directly but the candidate has disability more than that then he/she can apply in Pwd quota i.e. person with physically disabled quota and if the vacancies are available in Pwd quota then you will definitely get a chance to take job there.

You can apply for,

1. ONGC

2. MDL

3.GAIL

4. BHEL

5. NTPC

6. IOCL

7. NPCIL

8. Vizag Steel

9. HPCL

10. MGL

And for many others PSU jobs too. So, prepare yourself for Gate examination and don't worry about it .