1911 Nobel Prize in Physiology or Medicine — Allvar Gullstrand

What You Will Learn in This Article

You will understand how the "squishy lens" of the eye, the living eye, was mathematically described, and why this mathematical description is connected to eyeglasses, contact lenses, LASIK surgery, and slit lamps today.

The Ophthalmologist Who Was Also a Physics Nobel Candidate

There's an interesting fact about Gullstrand. He was also a strong contender for the Nobel Prize in Physics. His work in establishing the optics of the eye through mathematical formulas was so precise that the Physics Committee seriously considered him. Ultimately, he was awarded the Nobel Prize in Physiology or Medicine because his subject was the "eye," a biological structure.

And here's an even more interesting fact: Gullstrand was the one who opposed Einstein's Nobel Prize. As a member of the Nobel Committee for Physics in 1921, he opposed Einstein's award, arguing that the theory of relativity was "not sufficiently established." Einstein eventually received the prize for his work on the photoelectric effect — and never received a Nobel Prize for his theory of relativity.

These two stories reveal his personality. He was an ophthalmologist with the attitude of a rigorous physicist who would not accept anything that could not be completely described mathematically. This personality led him to tackle the extremely difficult problem of the optics of the eye.

The Zeitgeist — From Optics in the Universe to Optics in Cells

In 1911 Europe, it was the age of optics. Six years had passed since Einstein published his theory of light quanta (1905), and Rutherford would discover the atomic nucleus in the same year. The interaction of light and matter was at the forefront of physics.

Optics was also a hot topic in medicine. After X-rays earned Röntgen the first Nobel Prize in Physics (1901), the use of light for diagnosis and treatment rapidly developed. The 1903 Nobel Prize in Physiology or Medicine was awarded to Finsen for his phototherapy. Understanding the eye, a natural optical device, was a problem at the forefront of this trend.

In contrast, 1911 was the year after the Japan-Korea Annexation. The colonial government was establishing its framework for governing Korea, and during this period, modern hospitals (Severance Hospital, successor to Jejungwon, and Dahae Hospital) existed in Daegu and Gyeongseong (Seoul), but most opticians were Japanese, and ophthalmology did not exist as a field of study. The fact that the knowledge we use today for eyeglasses and LASIK surgery was established in Europe during this period shows how geographically biased scientific history has been.

There is another historical context to consider. This was a period of rapid growth in the precision optical instrument industry. Carl Zeiss's Jena factory collaborated with Gullstrand to create the slit lamp in 1911. This is the prototype of the device we see today in ophthalmology clinics, where we rest our chin and are exposed to blue light.

The Story of the Man — The Son of an Optician, Conquering the Eye with Equations

Gullstrand was born in Landskrona, Sweden, in 1862. His father was a physician and optician. He grew up watching people get fitted for glasses, and he began to wonder, "Why do some glasses fit well, and why do others cause dizziness?"

He began studying medicine at Uppsala University, but he soon became fascinated by mathematics and physics. This combination would define his life. After receiving his Ph.D. in medicine from the Karolinska Institute in Stockholm, he worked as a clinical ophthalmologist and spent his evenings solving optical equations. The title of his doctoral thesis was "On the Refractive Theory of Astigmatism." He attacked a clinical problem with physics.

To understand why his approach was novel, we need to understand the situation at the time. Until then, eyeglass prescriptions were based on empirical techniques. Opticians would repeatedly change lenses, asking, "How does this feel?" This approach worked well for simple cases such as nearsightedness and farsightedness, but problems involving multiple axes, such as astigmatism, always involved trial and error.

Gullstrand wanted to replace this entirely with mathematical formulas. His goal was to create a system in which "measuring a patient's eye would allow an equation to calculate the correct lens." To achieve this goal, he had to redefine the eye as an optical system.

His life during this period was extreme. Clinical work during the day, equations at night. His wife recalled that "he sometimes stayed in his room for three days writing his papers." And finally, he completed the multi-surface lens equation that treats the cornea, lens, and vitreous body as individual refractive elements.

Key Achievements — Describing the Eye as a Rendering Pipeline

The Eye as a Multi-Lens System

The model Gullstrand established is now known as the "Gullstrand schematic eye." The key to this model is that the eye is viewed as a system of multiple optical elements arranged sequentially:

1. Anterior corneal surface (n=1.376) — first refraction
2. Posterior corneal surface — second refraction
3. Anterior lens surface (n=1.406) — third refraction
4. Posterior lens surface — fourth refraction
5. Retina — final image plane

He treats how light refracts at each interface with individual equations, and applies the results sequentially. The CS analogy fits naturally here. This is an early form of ray tracing. It is conceptually the same as tracing each ray of light, calculating the refraction at each surface, and calculating the final position — the same as what modern 3D rendering engines do.

Alternatively, it can be compared to a graphics pipeline. Each refracting surface corresponds to a shader stage, and the entire eye is a multi-stage pipeline. Gullstrand provided the mathematical specification for each stage of this pipeline.

However, this analogy breaks down here. In a software pipeline, each stage is a fixed function, but the lens of the eye is living and controlled by muscles. It thickens when looking at near objects and thins when looking at distant objects. This is accommodation, and it is what Gullstrand treated with particular precision. He provided different equations for each accommodation state — as if the eye could have multiple configurations, like a state machine.

Slit Lamp and Anti-Reflective Lenses

Gullstrand's theory led to actual tools. This is the reason his Nobel Prize was not just for pure theory.

The slit lamp is a device that projects a narrow beam of light into the eye to observe the inner structures of the cornea, lens, and vitreous body layer by layer. This device, co-developed by Gullstrand and the Zeiss factory, is still an essential tool in all ophthalmology clinics today. It is the device we see in ophthalmology clinics where we are told to rest our chin and forehead and exposed to blue light.

Anti-reflective eyeglass lenses also came from his theory. With the ability to calculate how much light is reflected at each refracting surface, it became possible to design lens shapes that minimize reflection.

Quantification of Refractive Errors

After Gullstrand, eyeglass prescriptions shifted from experience to calculation. The following concepts come from his theory:

• Diopter — the unit of refractive power of a lens. The "-2.5 D" we use when getting eyeglasses today.
• Principal points — define the effective lens position in a multi-lens system.
• Nodal points — the center of rotation of the optical axis.
• Formulas for calculating far and near focal lengths

Without these concepts, today's optician examinations (autorefractor, visual field test, prescription lens selection) would not be possible.

Why It Matters

Gullstrand's Nobel Prize was an event that showed that "clinical problems can be completely conquered with physics." Until then, eyeglass prescriptions were an art. After Gullstrand, it became an engineering discipline.

The larger meaning is the establishment of the recognition that "parts of the body can be treated as engineering systems." The eye is an optical system, the heart is a pump system, and the kidney is a filter system — this perspective led to the bioengineering of the late 20th century. The fact that we can create artificial hearts, artificial kidneys, and artificial lenses today is made possible by this perspective. Gullstrand was the one who established the prototype of this perspective.

And he left us with a lesson: "Clearly distinguish between the parts that can be described mathematically and those that cannot." Gullstrand conquered the optics of the eye with mathematics, but he did not touch the problem of perception, that is, how the brain interprets images. He knew exactly where his methodology was valid. This self-awareness is why his theory remains in the first chapter of ophthalmology textbooks even after 100 years.

LASIK corneal reshaping calculations, contact lens curvature design, artificial lens power determination — all are descendants of Gullstrand's equations. If you are reading this sentence while wearing glasses, Gullstrand's legacy is behind the calculation of the power of those glasses.

Gullstrand Schematic Eye Pipeline Summary: Light passes through four refractions: the anterior and posterior surfaces of the cornea, and the anterior and posterior surfaces of the lens, and forms an image on the retina. Each interface is defined by a refractive index and curvature, and the parameters of the lens interface vary depending on the state of accommodation.

→ Experience it with coding: DevBench — Pipeline Architecture → Learn about CS concepts: DryBench — Ray Tracing and Rendering