A Brief History of the study of Vision and Optics
What is vision?
Vision is defined as the faculty or state of being able to see.
- Vision forms one part of our five basic senses.
- Vision and the ability of sight is how you’re reading this article right now!
But what is involved in vision, and how do we see?
- Today, we know that vision is a product of light entering the eye and being refracted by the lens in order to stimulate the retina (a process called accommodation).
- Nerve signals travel along the optic nerve to the visual cortex in the brain, and eventually an image forms, which we see.
- As shown by the diagram below, this process is quite complicated and numerous different types of cells are used to facilitate vision, which we won’t focus on in this article.
- The complicated pathways above won’t be focus of this article. Instead, we turn our attention to how we came to know all this information, who took interest and investigated this matter.
The Father of Optics
A close look at the birthplace of optics leads us to a figure known as Hasan Ibn al-Haytham, otherwise known as the Father of Optics.
- Born in 10th Century Iraq, Ibn al-Haytham was a Muslim Arab mathematician, astronomer, and physicist of the Islamic Golden Age.
- Ibn al-Haytham’s work was remarkable for its emphasis on proof and evidence, in particular using experiment to verify theory, showing similarities to what later became known as the modern scientific method.
If learning the truth is the scientist’s goal… then he must make himself the enemy of all that he reads ~ Hasan Ibn al-Haytham
- He was invited to Egypt to help build a dam on the Nile. After a field visit, he declined to proceed with the project causing him to end up under house arrest for 10 years!
- While under house arrest, he observed light entering a dark room, and using this studied light and vision- making major breakthroughs
- He was the first to explain that vision occurs through light rays reflected off of objects and into our eyes, a concept which directly contradicted the popular ‘emissary theory’ of the time, which thought that the eye itself emitted light.
- One day he saw light shining through a tiny pinhole into his darkened room — projecting an image of the world outside onto the opposite wall. Ibn al-Haytham realized that he was seeing images of objects outside that were lit by the Sun. From repeated experiments he concluded that light rays travel in straight lines, and that vision is accomplished when these rays pass into our eyes.
- He confirmed his discovery by experimenting with his dark room, and conducted additional experiments with lenses and mirrors which he built himself.
- He was also the first to demonstrate that vision occurs in the brain, rather than in the eyes.
- Through his studies of earlier work by Galen and others, he gave names to several parts of the eye, such as the lens, the retina and the cornea.
- His work on vision ultimately cumulated into the Book of Optics, which he wrote around 1027.
- The Book of Optics was translated into Latin and had a significant influence on many scientists of the Middle Ages, Renaissance and Enlightenment.
- Without a doubt, Ibn al-Haytham has contributed significantly to the topic of Vision and Optics. His story is inspiring and exhilirating, and he is very mich deserving of his title as the ‘Father of Optics’.
- It’s quite ironic how his punishment of being put under house arrest actually helped him devise the experiments and theories behind vision and optics.
- It just goes to show that sometimes an obstacle or setback can turn out to be a blessing in disguise, it all depends on how you look at it (pun intended)!
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References:
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Daneshfard, Babak (2016), “Ibn al-Haytham (965–1039 AD), the original portrayal of the modern theory of vision”, Journal of Medical Biography, Sage Publications, 24 (2): 227–31
El-Bizri, Nader (2010). “Classical Optics and the Perspectiva Traditions Leading to the Renaissance”. In Hendrix, John Shannon; Carman, Charles H. (eds.). Renaissance Theories of Vision (Visual Culture in Early Modernity). Farnham, Surrey: Ashgate. pp. 11–30. ISBN 978–1–409400–24–0
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