Vision Calculator

Vision testing and measurement have come a long way since Dutch ophthalmologist Herman Snellen developed his revolutionary eye chart in 1862. This landmark invention—featuring a large letter "E" at the top and progressively smaller letters below—established the foundation for standardized vision assessment that we still use today. Before Snellen's innovation, vision evaluation was largely subjective and inconsistent, relying on a patient's ability to read text at various distances without any standardized methodology.

Throughout the 20th century, vision measurement evolved from this simple beginning into sophisticated systems used by eye care professionals worldwide. Our calculator bridges these various notation systems that emerged across different regions and medical traditions, helping patients understand the relationships between these seemingly different ways of expressing the same visual capability.