Doctor

First, take your Senior Secondary Examination (I.e. your 12th class board exam) and score at least 60% in all the subjects.
Then you have to try for various medical entrance examinations like AIPMT, AIIMS, JIPMER, various State PMTs, etc. and achieve a good rank (it is easier said than done, although the level of examination is not that tough overall, but the number of seats is quite less which is why the selection rate is very low, even lower than IITs).
And then finally, complete your MBBS from a reputed medical college.
Congrats! You are a doctor!
But most students after MBBS try to specialise in a specific field (I.e. MD/MS). For that, you have to take the PG (post-graduate) medical entrance exams like AIPGMEE, etc. (Even more tough) after completion of your MBBS.
After PG, some opt for M.Ch./DM, etc. but that's completely up to you.
Take years of experience and then probably you'll get selected to be onboard on AIIMS as a panel doctor.

Hi,
Ophthalmologists are doctors who specialize in the medical and surgical care of the eye. The field is divided into general ophthalmologists and surgical ophthalmologists. Surgical ophthalmology includes a number of sub-specialties such as retina-uveitis, cornea/anterior segment, and ophthalmic plastic and reconstructive surgery. All of these specialists use lasers for refractive or other surgical procedures. Like all doctors, ophthalmologists are highly trained medical professionals with an undergraduate degree, medical school and a four-year residency under their belts. Surgical specialists undertake an additional one to two year fellowship to learn the latest techniques and the use of the newest equipment.
Complete a Bachelor's degree program in a field of your choice. Take advanced math and Science classes to increase your preparation for medical school. It also is important to make good grades, as admission to medical school is highly competitive.
Enroll in medical school. Medical school is a challenging four-year academic program, including two years of class work in physiology, biochemistry and pharmacology, and two years of practical experience working with doctors hands-on at hospitals and clinics.
Apply for surgical ophthalmology residency programs in your last year of med school. Ophthalmology residency programs typically last four years, often including a one-year residency, and the resident gradually is given more responsibility as she gains experience. You will be working with surgeons who perform various laser eye procedures during your residency. You qualify for an unrestricted license to practice medicine after you complete your residency.
Apply for a surgical ophthalmology fellowship in your area of interest after you complete your residency. Ophthalmic surgical fellowships in glaucoma, retina/uveitis, and cornea/anterior segment, which all involve laser procedures, usually take one to two years.
Join a surgical ophthalmology practice in your area. Work for a few years to gain experience in ophthalmology and laser surgery, and then you can decide whether to work toward a partnership in your practice or explore other opportunities.