The modern period
Ophtalmology > The modern period

The modern period

The Renaissance: the eye as a darkroom
Anatomy of the eye of Vesalius’s De Fabrica
Anatomy of the eye of Vesalius’s De Fabrica

The Renaissance opened new horizons for several artistic and scientific disciplines. Humanism multiplied the centres of interest while progressively promoting the use of critical thinking, which, gradually, was systematically adopted. Medicine, however, and ophthalmology in particular did not really evolve. Like the Arabs who did not question Galen’s or Hippocrates's theories the ophthalmologists of the Renaissance were the only ones in the medical field who took longer to develop a new way of thinking.

An important phenomenon in this framework, however, is the re-emergence of dissection, which was practiced in Italy in Bologna or in Padua. Leonardo da Vinci (1452-1519) did not hesitate to dissect human bodies. As a result he proposed an anatomy with the retina as the centre of sight but he continued to situate the lens in the centre of the eye, an error of the inherited tradition. Leonardo was one of the first to attempt to compare the eye with the camera obscura (darkroom) while being unable to figure out the question of the inverted retinal image. Unfortunately his treatises remained unknown for quite a long time, largely because they were never completed and had been written in an illegible hand.

In 1543 Andreas Vesalius published his magnum opus, "De humani corporis fabrica”, which went on to become one of the seminal works of modern anatomy. However Vesalius also was unable to avoid certain errors or inaccuracies in his dissection of the eye. Moreover the scientific minds of the time were also rather wary of medical advances, swearing blind loyalty to Galen and despising the idea of using illustrations in books.

The inability to properly situate the lens in the eye and to break away from the ancient theories partly explains the slow progress made in ophthalmology at the time. Paradoxically a man who thought that the lens was at the centre of the eye brought about a major development. Around 1600 Hieronymus Fabricius, a physician who trained at the University of Padua, correctly situated the famous lens as being more to the front of the eye and "defined the optical centres of several of the eye's surfaces”.

Engraving taken from Descartes’ Dioptrics
Engraving taken from Descartes’ Dioptrics, showing a man observing the image which is perceived by the retina of a cow’s eye

This discovery gave rise to several works in the field of optics. In 1604 Johannes Kepler gathered all the available contemporary knowledge as well as the facts which he gleaned from Ibn al-Haytham's Book on Optics. He considered the lens as an optical tool instead of thinking of it as a receptor and defined the “elementary properties of the eye” by demonstrating that “the representation of external objects was formed at the back of the eye”.

Like the hydraulic machines which William Harvey used as a metaphor for blood circulation the darkroom emerged as a model for the eye: “The eye is conceived as a spherical dark chamber, with a hole which contains the lens and a screen which acts as a retina on its back wall”. Descartes pushed this idea even further “marvelling at the inverted small image which is projected on the retina”.

Seventeenth century: from macro to micro
Replica of van Leeuwenhoek’s microscope
Replica of van Leeuwenhoek’s microscope

Around the same time Galileo’s telescope (1608) stimulated an interest in optics, the action of rays of light and the possibilities for enlargement, while Newton, several decades later, became interested in colour dispersion.

The Dutch naturalist Jan Swammerdam (1637-1680) meanwhile was able to find enlarging lenses, which at the time were used to observe the infinitely smaller aspects of our world. In 1658, at the age of barely 21, he described the red blood cell for the first time. A few years later Antonie van Leeuwenhoek, a draper who was worried about the quality of his fabrics, used the microscope and the techniques developed by Swammerdam to refine his own instruments. He soon veered towards microbiology describing the bee’s sting among others. Apparently his instruments could enlarge up to 300 times.

Van Leeuwenhoek may well have been the first to have discovered the rods and cones, which are the two photoreceptors of the retina. At the same time anatomical progress was also made. The posterior chamber, which is situated between the iris and the lens as well as the retina's central artery and the embryonic structure of the lens were now included in anatomical prints.

But at a time when scientists gradually acquired a better understanding of eyesight eye medicine by contrast stagnated somewhat. In the sixteenth century the German Georg Bartisch, who is considered one of the fathers of modern ophthalmology, devoted entire chapters in his works to (black or white) magic and to witchcraft as well as describing eye operations in a very detailed manner. Surgeons like Ambroise Paré, however, perfected eye wound care and systematically recorded their experiences in treatises which were filled with informative facts.

Eighteenth century: Daviel extracts a cataract
Drawing representing Daviel’s technique
Drawing representing Daviel’s technique

It was not until the mid-eighteenth century that the first significant therapeutic progress was made. Around this time a French ophthalmologist called Jacques Daviel turned the treatment of cataracts upside down. Since Susruta, the great Indian surgeon (800 BC to 600 BC) the operation to resolve clouding of the lens had not changed that much. Daviel, who had worked on the king's galleys and then levered cataracts at the Portuguese court, already had some solid experience.

In 1745, he operated on a hermit who wanted to save his left eye after a botched operation. Things started out badly: Daviel tore the lens while trying to lever it. Soon blood clouded the iris and the pupil. The surgeon then tried to enlarge the opening of the cornea and remove the clouded pieces of lens and the blood. The operation was a success and the patient soon could see again. Unfortunately the hermit suffered a "suppuration” of the eye, becoming permanently blind at a time when anaesthesia and antibiotics were completely unknown. Far from giving up Daviel refined his technique, repeating the operation over a hundred times, successfully this time. In spite of its effectiveness it would take more than a century before this “extra-capsular extraction of a cataract” became common practice. It is still the basis for present-day treatments.

Dalton and inverted colours
At the end of the eighteenth century an English chemist called John Dalton realised that he had trouble seeing colours properly. He started to study these eye problems which are due to a malfunction of the cones of the retina which are supposed to perceive the primary colours and submitted a study to the Manchester Literary and Philosophical Society in 1798. Although the official name of this phenomenon is dyschromatopsy it is better known as colour blindness. Colour blindness is a widespread phenomenon, which affects one in ten men and one in two hundred women. The most common form is red-green colour blindness.

In the eighteenth century modern eye anatomy progressed thanks to the works of the German botanist and anatomist Johan Gottfried Zinn. He proposed studying the eye layer by layer, describing what is known today as the zonule of Zinn, a ring of fibrous strands which "hold” the lens in place.

Nineteenth century: the development of a discipline

Over the centuries ophthalmology was mainly the realm of general practitioners, whereas the research in this field and in optics was conducted by various scientists, anatomists, astronomers, humanists or polymaths (experts in several fields) such as Descartes or Pascal. In the nineteenth century the discipline became significantly more specialised but at the same great progress was also made in the field of eyeglasses.

Since their development in the thirteenth and fourteenth centuries the eyeglass trade was populated with badly trained itinerant peddlers who considered this a product like any other. In the early seventeenth century Kepler finally explained how concave and convex lenses could be respectively used to correct myopia and presbyopia. The ingenious Benjamin Franklin, who could not see far or near and who was fed up of having to continuously switch glasses, invented bifocals in the eighteenth century.

The next century started with a remarkable discovery: astigmatism. The great scientist Thomas Young demonstrated this with his own eyes as he suffered from this affliction. But the first corrective measures were only developed about twenty years later, when the Astronomer Royal Sir George Biddell Airy invented cylindrical lenses. Subsequently, in the nineteenth century, the Dutch ophthalmologist Franciscus Donders made a crucial contribution to the growing adoption and prescription of eyeglasses in his book: "The anomalies of refraction and accommodation" (1864).

Hunting down glaucoma
Ophtalmoscope with tilting mirrors
Ophtalmoscope with tilting mirrors

If there is one disease that has been the subject of extensive scrutiny in the nineteenth century it has to be glaucoma. Although the term was coined by Hippocrates, who used it to designate blindness in the elderly, it has been used for several afflictions over time. The Romans often used it to refer to cataract but it was not the same disease.

In the seventeenth century Richard Banister, the first oculist to write a book in English on ophthalmology, remarked that the eyes of patients who were treated for cataract and who did not recover their eyesight was relatively hard. He listed the symptoms: “eye strain, the long duration of the disease, the absence of light perception and the presence of a fixed pupil. " The eye strain was confirmed by the Scotsman William MacKenzie in 1835 and Donders identified simple glaucoma, which occurred without an inflammation.

A major invention facilitated the diagnosis of glaucoma and had a significant influence on the profession: the ophthalmoscope, which was developed in 1850 by Hermann von Helmholtz. By illuminating the internal environment of the eye, or the fundus, he gave ophthalmologists the opportunity to detect any changes caused by glaucoma.

Albrecht von Graefe
Albrecht von Graefe, considered the greatest ophthalmologist of the nineteenth century. He is recognised as being one of the first ophthalmologists to make extensive use of the ophthalmoscope and for completing the first successful glaucoma surgery.

In 1856 Albrecht von Graefe, who is widely considered one of the greatest ophthalmologists of the nineteenth century, completed the first successful glaucoma operation or iridectomy (partial removal of the iris). In 1973 finally scientists discovered that glaucoma actually is a degenerative disease of the optic nerve, the pathway which carries impulses from the eye to the brain. The first pharmaceutical treatment became available in 1875, thanks to the discovery of pilocarpine.

Finally it is worth remembering that the nineteenth century was a period of major surgical progress, thanks to the arrival of anaesthetics, to antiseptic surgery as well as to Pasteur’s bacteriological research. All these developments contributed to the evolution of eye surgery in the long term.

Twentieth century: the great leap forward
Vladimir Filatov
Ukrainian coin featuring the portrait of Vladimir Filatov

In the nineteenth century the diagnosis was at the centre of all the progress made in ophthalmology. In the twentieth century one of the major advances related to a pharmaceutical development. Thanks to antibiotics diseases which previously resulted in blindness could be treated while more targeted medicines were increasingly often used to treat specific pathologies. From the start of the twentieth century significant progress was made as regards the quality of the microscopes, which helped further refine the histological studies of the eye.

Around 1920, Jules Gonin of Lausanne became interested in retinal detachment, an affliction which, at the time, inevitably would lead to blindness. He discovered that the detachment was always preceded by a retinal tear, which allowed the liquid in the eye to escape resulting in the detachment. He then succeeded in operating the detachment using a technique, now obsolete, called ignipuncture. The aim was to cauterise the retinal tear with an extremely hot sharp instrument.

In 1905 Eduard Zirm, a Czech ophthalmologist, was the first surgeon to perform a successful corneal transplant, removed from the eyes of a teenager which were incurable due to an accident that left metal pieces in them. In 1931 the Russian Vladimir Filatov succeeded in performing the same operation, which he had been trying for twenty years, but using the eyes of a deceased person.

The treatment of cataract also improved soon after the Second World War. During the war the ophthalmologist Harold Ridley realised that the splinters of the acrylic plastic cockpit canopies which were lodged into pilots’ eyes did not trigger rejection. This marked the start of research into intra-ocular lenses to correct cataracts.

In terms of instruments for correcting eyesight contact lenses, which were used before the Forties to protect the eye, were significantly improved after the war.

A Belgian in the pantheon of ophthalmology
Many of his colleagues consider Charles Schepens (born in Mouscron in 1912 and died in 2006) the “father of modern retinal surgery". As a former medical officer of the Belgian Air Force and an active member of the Resistance Schepens migrated to the United States in 1947. He invented an especially handy ophthalmoscope to examine the retina but above all he is known for developing a surgical technique, called scleral buckling, to treat retinal detachment. This method doubled the success rate of this operation.

The big difference between the ophthalmologist of the Fifties and the present-day ophthalmologist lies in the growing use of technology. Information technology is increasingly used in eyesight exams and in the twentieth century several devices capable of analysing eyesight were developed. Slowly but surely microsurgery and laser operations were introduced. Refractive photo keratoplasty is increasingly used to treat myopia, for example.

The range of possibilities for this discipline, which is one of the oldest and richest in the field of medicine, is more open than ever.