Niels Ryberg Finsen

Niels Ryberg Finsen (15 December 1860 – 24 September 1904) was a Danish-Faroese physician and scientist who was awarded the 1903 Nobel Prize in Medicine for opening a new path in medical science through his contribution to the treatment of diseases — especially lupus vulgaris — with concentrated light radiation. Finsen's most important achievement was his pioneering use of concentrated light radiation in the treatment of lupus vulgaris.

Life and Scientific Journey

Niels Ryberg Finsen was born in 1860 in Tórshavn, capital of the Faroe Islands, into a family with roots in Iceland. He began his education in the Faroes and in Iceland; in 1882 he moved to Denmark to continue his medical studies at the University of Copenhagen, graduating from the faculty of medicine in 1890. After a short period as a general practitioner, in 1893 he devoted himself entirely to scientific research.

While at university Finsen developed Niemann-Pick disease, a metabolic disorder causing fatigue and anaemia. This progressive illness, from which he had suffered since youth, weakened him physically; but he noticed that he felt more energetic after spending time in sunlight. This personal experience aroused his curiosity about the therapeutic properties of light and led him to study scientifically the effects of light on living things. To support his research financially, he continued to give private lessons to medical students.

Finsen announced his first significant findings in phototherapy in 1893, in his work Om Lysets Indvirkninger paa Huden (On the Effects of Light on the Skin). His research into light therapy also earned him academic recognition. In 1896 he became the founding director of the Medical Light Institute in Copenhagen (later renamed the Finsen Institute in his honour), where systematic studies of light therapy were carried out. Thanks to his scientific achievements he was awarded the title of professor at the University of Copenhagen in 1898 and was honoured with the Danish Order of the Dannebrog in 1899.

Although his health deteriorated further toward the end of the 1890s, Finsen continued to work even from a wheelchair. He died in Copenhagen on 24 September 1904, just forty-three years old. Despite his short life, his contributions to science earned him a respected place in his country and around the world.

Scientific Work: Light Therapy and Lupus Vulgaris

At the end of the 19th century knowledge of the biological effects of light was growing rapidly. In particular, it had been known since the 1870s that some bacteria could not develop under ultraviolet light. Building on this, Finsen proposed that light might have a healing effect on skin diseases caused by bacteria.

In 1893 he discovered that patients with smallpox who were exposed to red light did not develop the characteristic scars of the disease. In 1895 he began treating cutaneous tuberculosis, also known as lupus vulgaris, with concentrated ultraviolet rays. UV light has a spectrum ranging from 100–400 nm, but the UV-C band (a narrow range between 260–285 nm) is strongly absorbed by the nucleic acids of microorganisms and breaks down viruses and bacteria at the cellular level. For this reason 262 nm is regarded as the peak bactericidal wavelength and the centre of the optimal bactericidal range. When UV-C photons penetrate viruses and bacteria they damage their nucleic acids, leaving them unable to reproduce and microbiologically inactive. Modern Niels Ryberg sterilisers operate at a UV wavelength between 260 and 280 nm.

For this purpose Finsen developed a device consisting of carbon arc lamps and special lenses. In this set-up — known as the Finsen lamp — a light source with telescopic arms mimicked the beneficial rays of the sun and focused UV rays on the diseased area of skin. During treatment Finsen applied pressure to the lesion to reduce blood flow, which would otherwise block light from penetrating deeply, thereby increasing its effect. His lamp produced a beam of light roughly fifteen times more concentrated than ordinary sunlight and could target a skin area of about 2 cm in diameter at a time.

[A photograph of Finsen's phototherapy device treating lupus vulgaris patients (1900s) can be inserted here. This carbon-arc-lamp apparatus could illuminate several lesions at once thanks to its multiple arms.]

The first eleven patients with lupus vulgaris — a severe and disfiguring disease of the time — were treated with this method in two-hour daily sessions over several weeks, and the results were published in 1896. Although the initial number of cases was small, Finsen reported effective results even on multiple lesions in the same patient. After this initial success he treated, free of charge, many poor patients ostracised from society because of facial lesions at the light-therapy centre he established in Copenhagen.

Lupus Vulgaris

Lupus vulgaris is a form of cutaneous tuberculosis caused by Mycobacterium tuberculosis. It usually appears on the face — around the nose, eyelids, lips, cheeks, ears and neck. Untreated, lupus vulgaris can produce painful lesions that cause disfigurement, contractures and deformity, and in long-standing cases it may progress to squamous cell carcinoma.

The disease begins as painless, reddish-brown nodules that gradually grow to form irregularly shaped red plaques. Lupus vulgaris typically appears in individuals with good natural resistance, often after a primary infection. Characteristic features include scaling at the edges of ulcers and scarring in the centre, and the lesions are more common on the face than on the legs. Lupus vulgaris is a rare disease characterised by a slowly growing, granulomatous plaque caused by the tubercle bacillus in the skin. The disease grows slowly over one to three decades. It usually has a thickened, psoriasis-like appearance, but on diascopy with a glass microscope slide grey-green foci ('apple-jelly nodules') appear because of the underlying granulomatous inflammation. Lupus vulgaris may arise from a focus of tuberculosis infection by endogenous spread (haematogenous, lymphogenous) or by direct extension; it may also develop as an exogenous infection — for example, in the form of tuberculosis verrucosa cutis, scrofuloderma scars or at the site of BCG vaccination.

Finsen's Success in Treating Lupus Vulgaris

Finsen achieved a major success in the treatment of lupus vulgaris using concentrated light radiation. Exploiting the bactericidal effect of ultraviolet rays, he was able to heal lesions caused by the disease. The method was more effective and less invasive than other treatments used for lupus vulgaris at the time.

By 1903, at an international conference on the eradication of tuberculosis, he presented the results of 804 lupus vulgaris patients treated in his clinic, reporting marked improvement or complete cure in 94 percent of cases. This success made light therapy widely resonant in the medical community of the time, and similar light-therapy institutes following the Finsen method began to be established in different parts of the world.

The results of Finsen's lupus vulgaris treatment are summarised in the following table:

Another important contribution Finsen made to light therapy concerned smallpox. From observations he made in 1893, he discovered that prolonged exposure to red light — obtained by filtering out the ultraviolet (violet) component — prevented inflammation of the pustules on the skin in smallpox patients. The characteristic pock-marks (scars) were reported to be markedly reduced in patients kept under red light. This finding illustrates how rigorously Finsen examined the biological effects of different parts of the solar spectrum. In fact, the common thread of his work on both smallpox and lupus vulgaris was that he laid the scientific basis for the idea that specific wavelengths of light can alter the course of a disease.

Finsen's 1896 publication Om Anvendelse i Medicinen af koncentrerede kemiske Lysstraaler (On the Use of Concentrated Chemical Light Rays in Medicine) documented the principles and early clinical results of light therapy in detail and became a masterwork in the field of phototherapy.

The Nobel Prize Process (1903)

Finsen's pioneering work in light therapy was crowned with the most prestigious scientific prize of the day. The 1903 Nobel Prize in Physiology or Medicine was awarded to him for his contribution to the treatment of diseases — particularly lupus vulgaris — with concentrated light. Finsen thus became the first Scandinavian scientist to receive the Nobel Prize in Medicine, and the only Nobel laureate of Faroese origin.

When news of the prize reached Copenhagen, Finsen — already gravely ill — emphasised that it confirmed the international success of his method and expressed his view that this work was now officially regarded as Denmark's. He could not attend the Nobel ceremony in Stockholm on 10 December 1903 because of his health; on the same day he sat in his wheelchair at his home in Copenhagen and received the congratulations of the institute's staff and friends.

Finsen chose to channel most of the prize money back into science and society. He announced that he had donated the 50,000-krone portion of the award to his own Finsen Institute and earmarked 60,000 kroner for a sanatorium he had founded for heart and liver disease. His generous gesture was reciprocated; two philanthropists who had previously supported the institute (Hageman and Jörgensen) followed Finsen's example and each donated a further 50,000 kroner to the institute.

This interest generated by the Nobel Prize increased support for light-therapy research and helped Finsen's ideas reach a wider audience. In speeches at the award ceremony it was said that Finsen had earned humanity's eternal gratitude for the relief he had brought to suffering.

After the Nobel Prize, Finsen continued to work; hoping to reduce the effects of his illness he ran experiments on a low-salt diet, and in 1904 published as his last paper a study of salt accumulation in the body. But not long after this publication he died in 1904, plunging the scientific world into mourning. The respect felt for Finsen by scientists and the public was immortalised when, after his death, a monument adorned with figures stretching their arms toward the sun — Mod lyset (Towards the Light) — was erected in Copenhagen.

Impact on Modern Medicine

Dr. Finsen's work in phototherapy paved the way for the medical use of light and left a lasting impact on modern medicine. Although the light therapy he applied to lupus vulgaris largely lost its original purpose with the discovery of antibiotics in the mid-20th century, the idea of using light as a medical tool laid the groundwork for many new treatments. Finsen's success encouraged the emerging field of radiation therapy (radiotherapy), promoting work on X-rays and radioactive substances. Soon, alongside light, sources such as radium also began to be tried therapeutically in cancer and skin disease. His studies likewise inspired laboratory techniques such as the use of ultraviolet light to sterilise bacterial cultures.

The idea that the controlled use of radiation can provide medical benefit also underlies the phototherapy applications widely used in dermatology today. For example, UVB phototherapy and PUVA (UVA light + psoralen drug) treatment are applied routinely in chronic skin disorders such as psoriasis and vitiligo, based on Finsen's principle of the healing effect of specific wavelengths. Similarly, the use of blue-light phototherapy for jaundice in newborns is an example of how vital light-based treatments can be in modern medicine. Methods like using bright white light to treat seasonal affective disorder (SAD) are also direct adaptations of the phototherapy approach Finsen pioneered.

Techniques such as low-level laser therapy (LLLT) and photobiomodulation, applied today with lasers and LED light sources, are being developed to support cellular regeneration and accelerate wound healing. These modern light-based therapies are nothing other than the continuation of Finsen's idea — the controlled medical use of light — with advanced technology. In short, even when not via his original method, Finsen's phototherapy discoveries indirectly paved the way for many of the light-based treatments used in medicine today.

Impact on Science and Future Generations

Finsen's findings on the use of light in medicine did not only influence his own era; they also inspired later generations of scientists. His Copenhagen light institute model was copied in many centres from Europe to America in the early 20th century, leading to the founding of similar phototherapy clinics. As a result, lupus vulgaris cases declined markedly worldwide, and this once face-destroying disease was brought under control in many people thanks to light therapy.

By giving the concept of heliotherapy (sunlight treatment) a scientific foundation, Finsen also paved the way for sanatoriums in sunny regions such as the Swiss Alps where tuberculosis patients received sunlight therapy. For example, the physicians O. Bernhard and Dr. Auguste Rollier achieved successful results in treating bone and skin tuberculosis by applying sunbaths at high-altitude centres. These developments were an indirect continuation of Finsen's work and reinforced confidence in light's healing power.

Remembered as a pioneer of phototherapy, Finsen presented a vivid example of scientific curiosity and innovative thinking, becoming a source of inspiration for future researchers. His research, springing from his own illness, offers a striking story of how scientists can turn personal observation into creative solutions. Moreover, Finsen's experimental approach — translating laboratory findings into a scientifically grounded clinical treatment — was an early example of translational research in modern medicine. Medical students and researchers today still learn from his legacy, knowing that a whole field like phototherapy was born thanks to his perseverance and innovation. With the Finsen Laboratory in Copenhagen and the Finsen crater on the Moon named after him, this pioneering scientist continues to bring light to humanity.

Dr. Finsen's Contributions to Medical Science

By breaking new ground in the treatment of lupus vulgaris with concentrated light radiation, Dr. Finsen ushered in a new era in medical science. His work inspired research into the medical benefits of light and laid the foundations of modern phototherapy. Building on the existing knowledge of light's bactericidal effect and reports of the positive influence of sunlight on cutaneous tuberculosis, Finsen developed his treatment.

Conclusion

Through his pioneering work in light therapy, Dr. Niels Ryberg Finsen made an important contribution to medical science. Breaking new ground in the treatment of lupus vulgaris with concentrated light radiation, he laid the foundations of modern phototherapy. His work is still used today in the treatment of many skin diseases and improves patients' quality of life.

Finsen's work was an important turning point for medicine. His discovery of the healing power of light led to the development of new treatments such as phototherapy and opened a new chapter in the treatment of skin diseases. Finsen's legacy is still felt in modern medicine and continues to inspire future research. His determination in the fight against disease and his passion for science have secured him an important place in the history of medicine.