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Astigmatism is a common distortion of the eye which causes blurry vision. This is caused by an irregular shape of your cornea or lens of the eye.

In England, Thomas Young discovered astigmatism in 1801 by using an updated version of an optometer. His updated version of the optometer allowed him to turn the slits to get a better overall view of the whole eye.
This allowed us to better understand why some people had blurry vision and also allowed for the advancement in the understanding of the human eye.

Sources (2):
http://www.blog.contactlensking.com/Thomas-Young-Astigmatism.php
https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/astigmatism

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The trichromatic theory of color discusses how color vision works. There are certain receptors in the eye that are sensitive to colors: blue, green, and red. Each of these receptors is responsible for every color we see.

In England in 1802, Thomas Young introduced the theory of color resulting from these three receptors. Later on, a researcher, Hermann von Helmholtz extended Young's research to introduce the concept of cone receptors being responsible for the vision of color. He discovered that these cones contained different wavelengths responsible for seeing color. Short wavelengths saw blue, medium wavelengths saw green and long wavelengths saw red.

The Young Helmholtz Theory of Color Vision has allowed us to perceive where and how the human eye perceives color.

Sources (1):
https://www.verywellmind.com/what-is-the-trichromatic-theory-of-color-vision-2795831

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The ophthalmoscope is the first device that could look into the eye further than what could be seen with just the human eye.

In 1851, Hermann von Helmholtz by creating a device that would direct a strong light into the eye from a small prism or mirror. This light reflected off the retina and back into the device to show a magnified image of the back of the eye. Included in this image would be the retina, optic disc, blood vessels, macula, and choroid.

This device led to the invention of the device used now a day known as the endoscopy.

Sources (1):
https://www.britannica.com/technology/ophthalmoscope

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The Snellen Eye Chart is used to measure visual acuity, how well one can see something without the assistance of visual help.

In 1862, Hermann Snellen invented the Snellen Eye Chart. Snellen got the idea from watching his colleague ask patients to look at a chart on the wall to determine vision problems. Snellen created two charts. The first one consisted of E being placed in different directions and patients being asked to identify the correct placement of the letter. The second chart consisted of different letters listed next to each other in lines. As these lines went down the size of the letters decreased, and each line increased the number of letters. Each patient was placed 20 feet away from the chart, if you could read the smallest letters you had what was considered 20/20 vision. This was commonly used on children and illiterate patients.

The creation of this chart has allowed us to properly diagnose vision problems and was very useful at this time due to needed good vision to work on machines and more advanced equipment while working.

Sources (2):
https://dmei.org/blog/the-snellen-chart-history-and-how-its-used-today/
https://www.verywellhealth.com/snellen-eye-chart-3422168

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Contact lenses are used as an alternative to glasses in correcting vision.

The first pair of contact lenses was created in Zürich in 1887, by Adolf Gaston Eugen Fick. These consisted of resting glass on the less sensitive part of tissue around the cornea. These were created from heavy-blown glass with a thickness of 18-21 mm. They could only be worn for a few hours at a time due to a lack of oxygen flow to the eye. They helped by creating a magnification of the eye, which in return allowed for better vision.

This invention led to many improvements to what we have now as contacts. Although it started off as just helping people who were considered nearsighted, later on, a version was developed to help both nearsightedness and farsightedness among other visual imparities.

Sources (1):
http://www.glasseshistory.com/glasses-history/history-of-contact-lenses/

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A digital phoropter is a digital device that is the same as a phoropter. It contains multiple lenses that can be switched back and forth to determine which lens is needed for vision correction.

This digital version of the phoropter can make eye exams more efficient and less time-consuming. This device can more accurately detect eye imperfections, impairments, and diseases.

Without the discovery of how the eye works and where certain impairments come from within the eye, many people would not be able to see clearly. There would be no form of vision corrective lenses, which would make everyday life a challenge.

Sources (2):
https://www.eyeglassguide.com/my-visit/vision-testing/phoropter.aspx#:~:text=A%20phoropter%20is%20an%20instrument,take%20will%20involve%20a%20phoropter.
https://www.visioncenter.org/resources/digital-eye-exams/

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Thomas Young would be the best to help guide you through this exhibit. He was a scientist in England who focused on the eye function of light and color. He is best known for the discovery of color vision and astigmatism, which created the first look into how the vision was perceived.

He is the sole scientist who introduced that the eye was able to have imperfections and a sense of where those imperfections came from. His discovery of astigmatism and the color theory led to many discoveries of how the eye works and ways that it can be corrected.

Sources (1):
https://www.britannica.com/biography/Thomas-Young