Monoyer chart

Eye chart used to measure visual acuity

The Monoyer chart is an eye chart used to measure visual acuity. It was developed by the French ophthalmologist Ferdinand Monoyer in 1872. The chart is notable for its use of letters to test vision, and it is one of the earliest tools used in ophthalmology for this purpose.

History

The Monoyer chart was introduced by Ferdinand Monoyer, a prominent figure in the field of ophthalmology. Monoyer's work in developing this chart was part of his broader contributions to the study of vision and eye health. The chart was designed to provide a simple and effective method for assessing the clarity of a person's vision.

Design

Échelle Monoyer

The Monoyer chart consists of rows of letters that decrease in size from top to bottom. Each row corresponds to a specific level of visual acuity. The letters are arranged in a way that allows for the assessment of vision at various distances. Typically, the chart is viewed from a distance of 5 meters (or 20 feet in some countries), and the smallest row of letters that can be read accurately indicates the person's visual acuity.

The chart is unique in that it uses a series of letters that spell out Monoyer's name vertically. This was a clever way for Monoyer to leave his mark on his invention.

Usage

The Monoyer chart is used in eye examinations to determine the clarity of a person's vision. During an eye exam, the patient is asked to read the letters on the chart, starting from the top and moving downwards. The smallest line of letters that the patient can read accurately is used to determine their visual acuity.

The chart is primarily used in Europe and other regions that follow the metric system, as it is calibrated for use at a distance of 5 meters. In other parts of the world, such as the United States, the Snellen chart is more commonly used.

Significance

The Monoyer chart was one of the first tools to standardize the measurement of visual acuity, providing a consistent method for assessing vision. It laid the groundwork for the development of other eye charts and vision testing methods.

Related pages

• Visual acuity
• Snellen chart
• Eye examination
• Ophthalmology