Man has always been deeply fascinated by the eye. During prehistory man carves drawings of eyes onto the walls of caves, inferring that the eye had a deeply mythical dimension. During pre-dynastic Egypt (8000 BC to 3400 BC) this cultural trait became even more widespread. The sun and the moon were said to be the eyes of Horus, one of the most important gods in Egypt who embodied the heavens.
Myth has it that Horus’s left eye was gravely injured during a battle with Set, the god-warrior who assassinated his father, Osiris. Thoth, the ibis-headed god, healed Horus’s eye, even using it to resurrect Osiris. In a sense the ancient Egyptians considered Thoth as the ancestor of all ophthalmologists. Horus’s eye transcended the legend entering people’s homes in the form of an amulet to help cure diseases.
The Egyptians quickly proved to be medical pioneers. Homer, Herodotus and even Pliny the Elder successively expressed their admiration for the progress made by the Egyptians in this field. The translation of the hieroglyphs of the Rosetta Stone in 1822 helped understand a series of medical treatises, including the famous “Edwin Smith” papyrus. Although the roll itself dates from 1500 BC it is considered to be a copy of an earlier text (around 2600 BC) written by a man of many talents called Imhotep. He was an architect, a poet, a philosopher but some also consider him to be the true father of modern medicine. Although it is a well-established fact that the Egyptians produced ocular prostheses, mainly for their mummies, not many people know that Imhotep described 29 eye diseases.
The World Museum’s collection in Liverpool has a number of instruments in its collection which may well be the first eye surgery instruments. These were found in the tomb of King Khasekhemwy, who lived in Upper Egypt over 4,700 years ago. These copper needles may have been used for cataract surgery. Today the progressive clouding of the natural lens behind the pupil still causes half the cases (about 20 million) of blindness worldwide. Although contemporary ophthalmology still faces the challenge of “making cataract surgery available to everyone” this eye disease was also a real public health problem in ancient Egypt because of the dust and the sand to which people’s eyes were exposed.
During the surgery flat copper needle knives were inserted into the patient’s cornea and used to lever the opaque lens away from its supports and tilt it into the eye’s vitreous gel. This was a rudimentary solution but at least the light could reach the retina once again. After the operation the patient could see again, albeit that his eyesight would be blurred. Interpretations differ however on the Egyptians’ capability to understand this disease so early.
The Ebers medical papyrus (around 1500 BC, named after the German Egyptologist who bought it in Luxor in 1873), in effect, does not mention this type of operation. Nine pages of the roll are devoted to eye diseases, describing, among others, blepharitis (inflammation of the eyelids), leukoma (an opaque white spot due to an eye injury), trichiasis (eyelashes growing back toward the eye) or the inevitable conjunctivitis and cataracts.
In the past recommended remedies often consisted of a mix of incantations and lotions containing various fluids extracted from animals. Cataracts, for example, were treated with “a poultice of goose fat and honey”, combined with an exhortation to the gods to “make the remedy even stronger”. In addition to this, the makeup which Egyptians used had cosmetic as well as strong therapeutic properties. One of the ingredients, laurionite, contained lead ions, “boosting the immune system and protecting the eyes from the eye infections that were so common in the Nile Valley”.
But the Egyptians were not the only pioneers in the ophthalmological field. In ancient India there were also early manifestations of eye surgery. The Vedas, the early sacred texts, already mention attempts to extract an injured eye. Ayurveda, or traditional Indian medicine, which was handed down orally and in writing, devotes one part of its pillars, the Salakya-tantra, to eye operations. While some sources estimate that the first eye treatments were administered around 2,500 BC on the Indian subcontinent the writings of Susruta are much more detailed in this respect.
This physician, about whom not much is known, apparently lived in Varanasi between 800 BC and 600 BC. He wrote the Sahita Susruta, a comprehensive treatise covering “all the fields of medicine”, and dedicated 18 chapters to the eye. Susruta considered that the eye was divided into five anatomical entities: the eyelashes, the eyelid, the sclera and the cornea, the choroid (the layer under the sclera) and the pupil. He also described 76 eye diseases as well as ways of treating them. Naturally these include cataract, which was quite common given India’s proximity to the equator. Susruta describes in detail an elaborate method consisting of levering the cataract, with anaesthesia using cannabis and wine and even the post-operative bandage which is imbibed with ghee (Indian butter) and root extracts, as well as the proper way of holding the needle before piercing the eye.
The ophthalmological knowledge of the Greeks and the Romans was permanently influenced by the earlier Egyptian research, especially as regards the formulation of drops or ointments which were used to treat eye infections after having been diluted.
Hippocrates for example left us a detailed description of trachoma (literally, hard eye), the bacterial eye infection which today is considered the leading cause of preventable blindness, mainly in the developing countries. The contribution of the father of medicine was mainly limited, in ophthalmology as well as elsewhere, to clearly distinguishing between the supernatural and the divine on the one hand and the practice of medicine on the other.
The research of Alcmaeon of Croton (fifth century BC) and of Herophilus of Chalcedon (around 330 BC to 260 BC) primarily focused on the anatomy of the eye. They were among the first to describe the optic nerve although their descriptions were not very accurate. Herophilus mainly worked in Alexandria, which had become the centre of the Greek world, and was one of the few scholars in his time to dissect human bodies, a practice which was widely regarded as a sacrilege.
Following the arrival of Greek scholars, Rome, which until then had contented itself with an extremely rudimentary medicinal practice, gradually became interested in ophthalmology with empiricists such as Celsius (the first Westerner to describe the levering of the cataract shortly before the Christian era) and Rufus of Ephesus (first-second century AD). The latter gave us a clearer knowledge of the eye's structure, having detected the conjunctiva or the membrane which lines part of the inside of the eyelid and the eyeball.
He also identified two distinct areas, one between the cornea and the iris and the other behind the lens stretching to the retina. Galen also made some changes to the rather simplistic concept of the eye, which did not evolve much until Vesalius’s research, in the early sixteenth-century. The great physician of Pergamum also studied the tear ducts.
The first sketches of the eye also started to appear in the beginning of the Christian era. In Alexandria Ptolemy started to study the reflection and the refraction of light, probably based on the research of Euclid and Archimedes during the second century AD.
The decline of the Roman Empire heralded the beginning of a dark age for science in the West. In ophthalmology as in many other fields the Arabs were at the forefront of the field. They also studied several Greek texts which were translated into Arabic before being handed down to western civilisation many centuries later. From the eighth century onwards Yuahan Ibn Masawaih, an Assyrian physician who worked in Baghdad, suggested a new way of operating cataracts using a suction tube. This technique, which never really became popular, was refined two centuries later by Ammar bin Ali Al Mawsili, who practiced it in Egypt and in Tiberias using a syringe with a hollow needle.
During the golden age of the Abbasid Caliphate (850-1258) eye doctors played an important role in society. Elaborating on the discoveries of the Greeks these scientists produced a significant amount of literature on the subject. Some of the most notable works include the Book of ten treatises on ophthalmology, one of thirty-six works focussing on the eye by Hunayn Ibn Ishaq (808-873) and the Book of Optics by Ibn al-Haytham (965-1040).
The former, who was greatly inspired by Greek and Roman physicians, introduced many subsequent European practitioners of medicine to Galen’s work while paving the way for new ocular research.
The Book of Optics, which discusses such diverse fields as the anatomy of the eye, optical illusions and psychology, brought about a significant change in the understanding of human eyesight. The two great theories which prevailed at the time postulated that rays emanated from the eye allowing us to see (according to Euclid and Ptolemy) or that external objects conveyed their shape to the eye (according to Aristotle and his disciples). Thanks to several experiments with light Ibn al-Haytham was able to conclude that eyesight was the outcome of rays of light emanating from all the points around an object towards the eye.
For two centuries the interest in ophthalmology continued to grow in the Arab world. Although there were no major anatomical evolutions (like the Greeks and the Romans the Arabs believed that the optical nerve was empty) some care techniques were nevertheless refined. Trichiasis, whereby the eyelashes grow towards the eye was tended to by removing the eyelashes in question and cauterising the roots.
An important question remains however. Since the early twentieth century several historians have debated the role played by Averroes in the identification of the retina as a key element in our eyesight whereas Galen attributed this role to the lens. Unfortunately the texts of the great scholar of Cordoba are too ambiguous to resolve these doubts.
At the end of the Middle Ages, around the time of the reconquista of Moorish Spain, Western European physicians started to take a keen interest in ophthalmology again. This slow renewal was largely due to the translation of certain Arab treatises in Latin, to the contacts between Spanish Sephardic Jews and to the last remaining traces of Greco-Roman knowledge which subsisted in the monasteries.
In the thirteenth century the treatises by scholars were nothing more than republications or compilations of Arabic works. Cataract surgery was usually performed by itinerant practitioners whereas eye interventions were carried out by established surgeons. One of the theorists was Peter of Spain, who primarily focused on eye hygiene and on medical treatments of eye diseases without therefore writing about eye surgery. In 1276 he was elected pope before dying a few months later when the roof of his palace collapsed.
Although the pre-Renaissance did not really focus on anatomy (in fact dissection was completely sidelined) it marked the advent of a crucial invention: eyeglasses. Although the first stonemason who was capable of cutting and grinding corrective glasses was probably the original inventor, a Berber by the name of Abbas Ibn Firnas (ninth century) thirteenth-century monks mainly started to examine eye problems. As they were the greatest readers of their time they must certainly have suffered the torment of presbyopia.
The English monk Roger Bacon was inspired by Ibn al-Haytham's work and confirmed that convex lenses were useful for enlarging objects. The first eyeglasses were probably manufactured sometime after 1250 in Italy although Marco Polo testified that he saw the Chinese use them around 1270. It is difficult to name the inventor of eyeglasses today, given the many different versions of their origins. We do know, however, that initially glasses or rocks were used for presbyopia and that they were set in frames made of leather, metal or bone and that the temples were not added until the fifteenth century. The progress made in glass manufacturing (more specifically the glass from Murano, an island near Venice) probably contributed to the widespread distribution of eyeglasses in the fourteenth century.
In addition to its revolutionary character the invention of printing (1450) also prompted a growing need for eyeglasses. In the Quattrocento the city of Florence thus became the hub for the production of eyeglasses and soon the first glasses for myopia were developed in the mid-fifteenth century.