Visual impairment covers a very wide range from simple near- or far-sightedness to total blindness. It is a disability which can be treated in a variety of ways, from spectacles and contact lenses to cataract surgery and intra-ocular implants. Opthalmic technologists are skilled professionals who work in hospitals and eye-clinics where they work with ophthalmologists in testing vision, and making spectacles and lenses.
For people who are interested in science and its practical applications, but are not interested in a medical career, this is just one of a range of paramedical options available in India.