Herman Snellen

Dutch ophthalmologist known for developing the Snellen chart

Herman Snellen (19 February 1834 – 18 January 1908) was a Dutch ophthalmologist renowned for developing the Snellen chart, a tool used to measure visual acuity.

Early life and education

Herman Snellen was born in Zeist, Netherlands. He pursued his medical education at the Utrecht University, where he developed an interest in ophthalmology. Under the mentorship of Frans Cornelis Donders, a prominent figure in the field, Snellen honed his skills and knowledge in eye care and vision science.

Career

Herman Snellen

After completing his studies, Snellen joined the Netherlands Institute for the Blind in Amsterdam, where he worked on improving methods for assessing vision. In 1862, he was appointed as a professor of ophthalmology at the Utrecht University, succeeding his mentor, Donders.

Snellen's contributions to ophthalmology were significant, particularly in the development of the Snellen chart in 1862. This chart became a standard tool for measuring visual acuity and is still widely used today. The chart consists of letters of decreasing size, which patients read from a fixed distance to determine their level of vision.

Snellen chart

Snellen chart

The Snellen chart was a groundbreaking innovation in the field of ophthalmology. It provided a simple and effective way to quantify visual acuity, which was crucial for diagnosing and treating vision problems. The chart's design, with its standardized letter sizes and spacing, allowed for consistent and reliable measurements across different settings.

The Snellen chart is typically used at a distance of 20 feet (6 meters) in the United States, where the term "20/20 vision" originates. In other countries, the metric equivalent of 6 meters is used, leading to the term "6/6 vision."

Later life and legacy

Herman Snellen continued to contribute to ophthalmology throughout his career, publishing numerous papers and advancing the understanding of eye diseases and treatments. He retired from his position at Utrecht University in 1903 but remained active in the field until his death in 1908.

Snellen's legacy lives on through the continued use of the Snellen chart, which remains a fundamental tool in eye care. His work laid the foundation for modern vision testing and has had a lasting impact on the field of ophthalmology.

Related pages

• Visual acuity
• Ophthalmology
• Frans Cornelis Donders