No, you cannot add the prefix "Dr." to your name if you have only a PhD in Optometry (OD)./

The title "Dr." is typically used for individuals who hold a doctoral degree (PhD) in a field that qualifies them to practice medicine. This includes fields like Medical Doctors (MDs), Doctors of Dental Surgery (DDS), and Doctors of Osteopathic Medicine (DOs).
OD" stands for Doctor of Optometry. While it includes the word "Doctor" in the title, it signifies a professional doctorate degree in optometry. Optometrists are not medical doctors and their scope of practice is different.

In most countries, including India, using the title "Dr." is generally restricted to medical doctors who can diagnose and treat a wide range of medical conditions, including prescribing medications and performing surgeries. Optometrists, while highly qualified healthcare professionals, have a specific focus on vision care. They can perform eye examinations, diagnose and treat vision problems, prescribe corrective lenses and medications for certain eye conditions, but their practice doesn't encompass the broader medical field.

I hope it helps!