Allvar Gullstrand was born in 1862 in the Swedish town of Landkroma where his father was the principal municipal medical officer. He subsequently attended the grammar school in the more northerly town of Jönköping where he was tutored in elements of mathematics that would later be a key element of his research work.
Between 1885 and 1888, Allvar Gullstrand studied medicine, following the career of his father and it seemed appropriate to select the speciality of ophthalmology since this could utilise specifics of mathematics that he had previously acquired.
After qualifying, he took up a post in the Seraphim Hospital in Stockholm. Being ambitious within the sphere of academic achievement his doctorate thesis, entitled Contribution to the theory of astigmatism, re-examined the prevailing models of astigmatism and was well received when published in 1890.
His appointment in 1891 as a lecturer at the Karolinska Institute would largely be due to his postgraduate studies. The subsequent award in 1895 of a specially created Chair of Professor of Ophthalmology at Uppsala University eventually allowed more time for researches into the structure of the eye where the publication in 1900 (in German), entitled General Theory of Monochromatic Aberrations and Its Implications for Ophthalmology,1 introduced him to the wider community of the science of optics.
The style of presentation used by Gullstrand in his mathematical models of visual functions is difficult to follow. In a specific work,1 for example, a chapter of 28 pages has over 150 equations all of which are unnumbered and without any diagrams.
This, however, appears to have been the conventional style for presentation of work of this kind. In addition, the bulk of his subsequent publications are in either German or Swedish, with only one major work2 available as an English translation.
Shape of the Cornea
While Gullstrand is sometimes credited with the first use of the ‘photo-keratotomer’ for determining the corneal profile, there is in fact an earlier trail of investigation and discovery, which Levene3 describes in some detail. A device for detection of abnormalities of the corneal topography had been developed by Henry Goode, a Cambridge physician in 1847, where the reflection of a square object from the cornea provided an indication of the corneal profile.
A more convenient device was developed by Antonio Plácido in 1880, where the reflection of a disk with concentric black and white rings could be viewed through a central aperture. The rings were typically illuminated by means of light situated behind and adjacent to the patient’s head.
Such devices are still available for screening applications. It is an observation that many of the early researchers into details of the corneal profile suffered from astigmatism.
While this technique could confirm the presence of degrees of astigmatism and other corneal issues (figure 2, pictured), visual inspection alone
could not provide confirmation of precise values of corneal topography or accurately record changes over time.
Levene3 also indicates that Plácido went on to develop the ‘photo-keratoscope’ in 1880 as a technique for recording the pattern of observed rings on the cornea and was a method independently developed by Emil Javal in France.
Later Gullstrand, in 1896, would use the technique to derive accurate measurements of the optical power of the anterior eye surface. Such measurements would identify key elements of his standard eye model.
Gullstrand took considerable care to make his measurements of the reflected Plácido ring profile – coating the photographic plate with a layer with the exact same refractive index as the glass plate to avoid double images. The measurement accuracy he achieved for measuring the location of points on the captured corneal image plate was of the order of 2.5 microns.
The high levels of illumination required was provided by a pair of 25 amp Siemens arc lamps. This level of direct exact observation explained many of the aspects of astigmatism related to aspects of the corneal profile.
Gullstrand endeavoured to simplify such observations for everyday practical use, but little notice of his efforts was taken in the wider world of ophthalmology.
Development of the Slit Lamp
The Czapski binocular corneal surface microscope developed in 1899 by Siegfried Czapski was a free-standing device, which would have been used with a diffuse light source. Czapski had migrated to work at Carl Zeiss (Jena) after successful academic studies and work under some of the luminaries of German optical science such as Hermann von Helmholz.
Czapski’s major published work4 has a documented style very much like that used by Gullstrand. This work was in fact a detailed account of the innovative optical concepts of Ernst Abee, the head of optical development at Carl Zeiss (Jena), who was apparently too busy to document his own work in detail.
While Czapski would succeed Abee in 1905 as head of technical developments at Carl Zeiss (Jena), Czapski would only retain this post for a short time following his premature death in 1907 at the age of only 46.
It is relevant not only to note the significant contribution of Ernst Abee in scientific optics, but his forward looking belief in the rights of the workers in Carl Zeiss (Jena) identified him also as a progressive social reformer.
Links with Carl Zeiss (Jena)
Gullstrand had first visited the Carl Zeiss (Jena) facility in 1901, meeting Czapski and others including Moritz von Rohr and Ernst Abee and collaborating in the development of various devices. It is noted, however, that there was a lack of engagement between Gullstrand and Abee, the technical director of Carl Zeiss (Jena).
The main objective behind Gullstrand’s development of the slit lamp was precision observation of anterior and posterior corneal topography to allow him to determine values for his eye model, in particular the corneal thickness. Initial work on the slit lamp was undertaken at the University of Uppsala incorporating the Walther Nernst lamp, which had been developed by Nernst at the University of Göttingen.
A key feature of the Nernst lamp was the use of a rod-like filament made from zirconium oxide-yttrium oxide. Not only was the lamp more efficient than the existing filament types, but it also did not need to be operated in a sealed gas environment. Nernst offered the patent to Westinghouse, the arch-rival of Edison and the General Electric company.
Some disadvantages, however, of the Nernst lamp was that it required to be initially heated by a separate filament to reduce its electrical resistance and it used elements of expensive platinum wire.
Walther Nernst was also a highly talented and perceptive scientist and would subsequently be awarded the Nobel Prize in chemistry in 1920 in recognition of his work in thermochemistry at the University of Berlin.
Initially, the Nernst slit lamp essentially developed by Gullstrand was a standalone device with the clinician observing the areas of illumination by means of a pair of handheld lenses and without any patient chin rest. It is recorded that initially Gullstrand only use x4 lens magnification.
The slit lamp system device was demonstrated by Gullstrand at the 37th assembly of the German Ophthalmological Society in Heidelberg in 1911, where its eventual key role in eye examination was probably not fully appreciated. It was not until around 1915 that Leonard Koeppe suggested to Zeiss the combination of Czapski’s binocular corneal microscope and the Nernst slit lamp.
Figure 4: The Czapski binocular corneal microscope (Image: Eye Antiques)
The head of development, Otto Henker, at Carl Zeiss (Jena) was able to demonstrate the new configuration in 1916. The binocular corneal microscope was mounted on a glass plate, which allowed its repositioning. In subsequent early versions the binocular unit appears to have independent x and y travel with locking positions available.
In time, Zeiss would add additional features to the system with particular options of light source, red-free light, system magnification, various coloured light filters and also options using polarised light.
In this phase of subsequent development for routine clinical use, Gullstrand would effectively play little or no part since his priority was in using the system to determine the physical structure of the eye for developing his standard eye model.
Figure 5: Original Nernst slit lamp (Image: wikimedia.org)
Gradual Acceptance of the Slit Lamp
There is an account in 1914 by Erggelet5 using the early system and a subsequent mention is a reference to the use of the device in two patients6 published in 1922. It is likely, however, that World War I hindered the uptake of the device although during the hostilities there would be a great need for such a device to diagnose and treat ocular trauma.
A significant boost to the use of the slit lamp was its demonstration by Gullstrand at the International Ophthalmological Congress in Washington, USA, in 1922. This was also a time where Gullstrand could act as a neutral agency in trying to reconnect international meetings relating to ophthalmology.
Some insight can be gained into the performance of Gullstrand’s slit lamp from the account of a certain TH Butler,7 an ophthalmologist from Birmingham who attended the second course of Professor Vogt in September 1923 at the University Eye Clinic in Zürich. The course was essentially structured over six days with two hours of lectures in the mornings and three hours of practical work in the afternoons.
Without exception, all participants found the operation of the instrument initially very challenging, but as the course developed, they found they could eventually investigate the structure of the anterior eye in a totally remarkable and novel way.
In the initial design, the microscope optics and illuminating optics were independent and the plane of focus of both had to be matched for direct illuminating viewing. There was also significance placed on additional modes of illumination, where, for example, a feature could be illuminated in scattered light or in light transmitted through adjacent tissues. Also, control of the size of the ‘slit’ or ‘ribbon’ was also identified as critical. There is a description of the ability to observe cells in the anterior chamber moving in micro convection currents.
Under guidance, the participants could observe anatomical details previously unknown to them in their routine clinical practice. There is no mention, however, of the anticipated value of the device in routine clinical use. While it had been identified that red-free light was advantageous for observing vascular structures, this was not an integral part of the initial design.
A comprehensive account of the evolution of the slit lamp is further described by Gellrich8 and Keeler.9 The important role that Prof Vogt played in giving prominence to Gullstrand’s optical developments is described by Gloor.10
Gullstrand Reflex Free Ophthalmoscope
While the ophthalmoscope developed by Hemholtz was in itself a significant advancement for routine examination of the retina, a major drawback to image quality was the reflection of illumination light from the corneal and lens surfaces. This led Gullstrand to develop various versions11, 12 of ‘reflex free’ ophthalmoscopes – one handheld and another stationary.
The first versions of these were developed by him in Sweden and were well received at the spring meeting in 1911 of the Swedish Ophthalmological Society. In one version developed subsequently by Carl Zeiss (Jena), the ‘large Gullstrand’ ophthalmoscope, with binocular option was identified as allowing observation of surface topography of the retina.
A more ‘basic’ model was also available as the ‘large simplified Gullstrand Ophthalmoscope’ in which there remained slight element of reflection from the optical lens elements.
In a Bausch + Lomb version of the large Gullstrand Ophthalmoscope there is described a ‘drawing apparatus in position’ to allow the observer to sketch the observed retinal profile.
Towards Retinal Camera System
The basic elements of imaging the ‘reflex free’ retina had been achieved, but it would be significantly later before a practical device for photographing the retina would be developed. This would be by JW Nordenson13 in consultation with Gullstrand and working with Zeiss, using essentially the optical principle of the large Gullstrand Ophthalmoscope.
The Nordenson retinal camera is described in detail in relevant Zeiss promotional literature. It is clear that the most complex component of the system was the compact carbon arc light source. The compact size of the overall system gives the impression of reduction of the number of optical components in order to reduce manufacturing costs and optical losses across paths of pupil illumination and image formation.
The optical design separated, as much as possible, the central optics of image capture from the system to illuminate the peripheral pupil though some element of reflection did also take place. The default shutter speed was 1/8th second and activating the shutter would swap out the neutral density filter to admit the full illumination level of the arc lamp during the exposure. A separate filter close to the arc lamp absorbed infrared radiation. A separate camera plate was exposed for each retinal observation.
Over time, there would be developments14 to the light source and camera mechanism type and with addition of flash photography the system would eventually come to be known as the fundus camera.
In Reflection
Nordenson15 would provide reflection on the work of Gullstrand on the centenary of Gullstrand’s birth. This account is perhaps one of the most valuable appreciations of Gullstrand’s work in English, since it deals principally with the theoretical aspect of his endeavours. It is therefore essential reading for anyone studying Gullstrand’s life and work. Nordenson, however, makes little reference to his own work in development of the ‘retinal camera’.
In all of the accounts relating to Gullstrand, there is very scarce information relating to his wife, Signe Christina Breitholtz, who he married in 1885. While Gullstrand had a brother and a sister, Signe had four brothers and three sisters, and most family relations would therefore have been on the Breitholtz side. Their only daughter Esther was born in Zurich but died of diphtheria at a young age. Nordenson, however, makes some mention of Gullstrand’s wife, describing her devotion to supporting her husband in his endeavours.
Einstein and Gullstrand
The academic rise of Gullstrand led him to become a member of the Nobel Committee for Physics in 191116, where it was the committee’s wish that the annual award should be given to Gullstrand. At the same time, the Nobel Committee for Physiology or Medicine was also considering him for their award.
The outcome was that Gullstrand was minded to accept the medical award for his ‘work on the dioptrics of the eye’ with his Nobel lecture entitled ‘How I found the mechanism of intracapsular accommodation’.17
Between 1911 and 1929, Gullstrand was a member of the Nobel Committee for Physics and its chair between 1923 and 1929. Between 1910 and 1922, Einstein was nominated over 10 times for the award in physics, often by leading figures in the field of physics.
In the committee debate of 1921, it is recorded that Gullstrand argued that the essential validity of Einstein’s theory of relativity had not been scientifically proved and that there was no benefit of it for humanity, which had been a condition of the award outlined by Alfred Nobel.
A way was found, however, to announce the award in 1921 for Einstein’s work on the photoelectric effect, which was received one year later in 1922. When eventually Einstein came to Sweden to deliver his Nobel lecture, it was entitled ‘Fundamental ideas and problems of the theory of relativity’.
Figure 6: Albert Einstein delivering his Nobel lecture
While there is attention given to the role that Gullstrand played in the apparent delay of the Nobel award to Einstein, less oversight is given to the role played by Gullstrand in the selection of Nobel physics laureates in the years 1923 to 1929, when he was chair of the committee. Grandin18 provides additional insight into the complex issues involved.
Epitaph
The labours of Gullstrand in researching and documenting his extensive investigations were demanding and Gullstrand is noted to have stated: ‘An academic teacher and scientist who is not trembling with exhaustion at the end of a semester has not done his duty.’
After retiring in 1927, Gullstrand died in 1930. Often the available documented extracts regarding Gullstrand from various sources only contain the relevant details in part, though there are on occasion elements that contain information which is highly relevant and of high quality, such as that provided by Nordenson.
The impression sometimes presented is that of a lone genius working in isolation but a more realistic assessment of his life and working respect of development of diagnostic equipment is to track interaction with co-workers and lines of development and investigation. It is certainly the case that a single article cannot hope to fully capture the extent of the work undertaken by Gullstrand.
The era of his work links with the high point of optical development in Europe and especially in Germany and where many aspects of development work that were challenging then remain relevant today.
A challenge for present day innovators of vision test equipment, for example, is in a way to be aware of the properties of the wealth of optical technologies now available, such as light sources, optical imaging components and image sensor devices.
Last, but not least, with the increased availability of language translation tools, the question arises, why have Gullstrand’s key publications and extensive research notes not been made available in English?
Figure 7: JW Nordenson of the Karolinska Institute in StockholmImage (Sydsvenska Medicinhistoriska Sällskapet)
References
- Gullstrand, Allvar, Allgemeine Theorie der Monochromatischen Aberrationen und Ihre Nächsten Ergebnisse für die Ophthalmologie (General Theory of Monochromatic Aberrations and Its Implications for Ophthalmology), Upsala : Berling, 1900
- Gullstrand, Allvar, Helmholtz’s treatise on physiological optics, Translated from the German ed. by James P. C. Southall. Published by the Optical Soc. of America [Rochester.] edn. G. Banta Pub. Co., 1924.
- Levine JR. The true inventors of the keratoscope and photo-keratoscope. Br J Hist Sci. 1965;2(8):324-42
- Czapski, Siegfried, Grundzüge der theorie der optischen instrumente nach Abbe, Leipzig : JA Barth, 1904 available at:- https://archive.org/details/grundzgederthe00czapuoft/page/58/mode/2up
- Erggelet H, Befunde bei fokaler Beleuchtung mit der Gullstandschen Nerst-Spaltlampe. Klin Montatsblatten für Augen, 1914;42:449-70
- Bedell AJ. Bridge Coloboma of the Iris-Slit Lamp Examination of Two Cases. Trans Am Ophthalmol Soc. 1922;20:350-2
- Butler TH. Professor Vogt’s Course On Slit-Lamp Microscopy. Br J Ophthalmol. 1923 Dec;7(12):551-8
- Gellrich MM, The Slit Lamp: Applications for Biomicroscopy and Videography, (Chapter History of the Slit Lamp), Springer Link, 2014
- Keeler, R in Marmor MF, Albert DM (eds,) Allvar Gullstrand: Dioptrics of the Eye and the slit lamp’, Foundations of Ophthalmology – Great insights that established the discipline, Springer publishing, Switzerland, 2017
- Gloor BP. Alfred vogt (1879-1943). Surv Ophthalmol. 2008 Nov-Dec;53(6):655-63
- Gullstrand A, Die reflexlose Ophthalmoskopie. Archiv für Augenheilhunde, 1911, 68: 101-14
- Henker, O, Einige Zusatzapparate für das grosse Gulstransche Ophthalmoskop. Bericht über die 39. Versammlung der Ophthalmologischen Gesellschaft. Heidelberg 1913
- Nordenson JW. Augen kamera zum stationaren Ophthalmoskop von Gullstrand. Ber Disch Ophthalmol Ges. 1925;45:278-288
- Bedell AJ. The Newest Model of the Nordenson Zeiss Photographing Ophthalmoscope. Trans Am Ophthalmol Soc. 1938;36:278-9
- Nordenson JW. Allvar Gullstrand (1862-1930). Doc Ophthalmol. 1962;16:283-337
- Ravin JG. Gullstrand, Einstein, and the Nobel Prize. Arch Ophthalmol. 1999 May;117(5):670-2
- Gullstrand Allvar, Nobel Lecture, How I Found the Mechanism of Intracapsular Accommodation, Available at: https://www.nobelprize.org/prizes/medicine/1911/gullstrand/lecture/
- Grandin, Carl. The difficult task to award Einstein a Nobel Prize, Il Nuova Saggiotora, 2021, Archivio, 37: 1-2
