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Keywords:

  • cornea;
  • history;
  • keratoconus

Abstract

  1. Top of page
  2. Abstract
  3. Keratoconus in the 18th Century
  4. Keratoconus in the First Half of the 19th Century
  5. Conclusions
  6. Acknowledgements
  7. References

In an era of scientific method, precision of nomenclature and an electronically accessible publication record, the early history of keratoconus still remains, in parts, as complex and perplexing as the disease itself. Historically, the disease has been somewhat confusingly referred to by several different terms, including hyperkeratosis, ochlodes, conical formed cornea, cornea conica, cornée conique, sugar loaf cornea, prolapses corneae, procidentia corneae, staphyloma transparent de la cornée, staphyloma pellucidum, staphyloma corneae totale conicum pellucidum, staphyloma diaphanum, keratconus and keratoconus. In his major 1854 treatise on conical cornea, John Nottingham is widely cited as the first author to succinctly define keratoconus and its associations; however, for 150 years prior to this landmark publication, others had been slowly deciphering elements of keratoconus and distilling their knowledge in a series of publications obscured by the passage of years. Uncritical re-writing of core information and references without their full verification has also led to confusion in the published literature in the 150 years since Nottingham's comprehensive description of keratoconus. In the light of the preceding limitations in the established literature, the authors conducted an historical survey, based on the analysis of original sources, to more fully establish the chronology of early descriptions of keratoconus prior to 1854, with particular focus on the works of Duddell, Taylor, Mauchart, Scarpa, Wardrop, Lyall, MacKenzie, Lawrence, Schmidt, von Ammon and Pickford. This review attempts to place the observations of these practitioners and others both in the context of contemporary ophthalmic practice and historical precedent.

The modern ophthalmic literature is full of conflicting and sometimes inaccurate data on the early descriptions of keratoconus. This might be caused in part by difficult access to older, original works written in different languages—mainly Latin, German, English and French.

Historically, keratoconus is somewhat confusingly referred to by several different terms,[1-4] including: hyperkeratosis (Himly[2]), ochlodes (meaning ‘annoying’), conical formed cornea, sugar loaf cornea, cornée conique, staphyloma transparent de la cornée, cornea conica, staphyloma pellucidum, prolapses corneae, staphyloma pellucidum conicum, staphyloma corneae totale conicum pellucidum, staphyloma diaphanum, procidentia corneae, keratoncus, keratoconus (von Ammon[3]), staphyloma conicum corneae pellucidum or in German durchsichtiges keelfoerges Hornhautstaphyloma.

Uncritical re-writing of core information and citation of references without proper verification, has also led to confusion in respect to the date and authorship of the original description of keratoconus. However, the majority of sources usually identify three authors: Mauchart (1748) (cited by Applebaum,[5] Caroline and colleagues,[6] Nielsen and colleagues[7] and McTigue[8]); Taylor (typically no date or reference provided) (cited by Zegers[9] and Tarkkanen[10]); or Duddell (1729, cited by Khachikian and Berlin[11] or 1736, cited by Hirschberg[12]). Sir Stewart Duke-Elder,[13] typically known for his accurate historical descriptions and his significant influence on 20th century ophthalmology, wrote that ‘the condition has been known from very early times (Mauchart 1748; Taylor, 1766), but it was first adequately described and distinguished from other ectactic conditions by Nottingham (1854)’. On this occasion, he may not have known the full story of ‘keratoconus’.

In the light of the preceding limitations in the established literature, the authors conducted an historical survey, based as far as possible on the direct analysis of original sources, to fully establish the chronology of early descriptions of keratoconus prior to Nottingham's landmark treatise in 1854.

Keratoconus in the 18th Century

  1. Top of page
  2. Abstract
  3. Keratoconus in the 18th Century
  4. Keratoconus in the First Half of the 19th Century
  5. Conclusions
  6. Acknowledgements
  7. References

Benedict Duddell

We have limited knowledge of Duddell (Duddel), who was born around 1695 and died around 1759 to 1767, indeed we cannot precisely establish his date of birth or death.[14] According to his own account in 1729,[15] in 1718, when in practice in Nottingham, he decided to be trained in eye diseases due to the failure to save the sight of a poor man with a large family and starving children. Thus, he journeyed to Paris to became a student of John Thomas Woolhouse (1660–1734), a famous English oculist, former oculist to King James II and surgeon to the Hospital des Quinze-Vingts, Paris.[14, 16-19] In Paris, Duddell had the opportunity to meet other Woolhouse students, including Zacharias Platner (1694–1747), later a professor of anatomy and surgery in Leipzig and Burkhard David Murchart (1696–1751), later a professor in Tübingen. From France, Duddell subsequently relocated to Hammersmith near London.[14, 16-19]

Duddell wrote three treatises in 1729,[15] 1733[20] and 1736[21] and one further work in 1732[22] is assigned by some researchers. He often differed with the leading contemporaries in his field; for example, he disagreed with Woolhouse arguing that the main cause of cataract was the clouding of the lens. He also disagreed with the eminent French surgeon, St Yves, arguing that the immediate organ of sight was the retina, not the choroid.[14, 16-19]

His anatomical knowledge was supplemented by his own dissections. In the description of the cornea, he noted that it is composed of several parts:[15]One may divide both the one and the other Portion of this Membrane into several Parallel Laminae’. Thus, for many years his name was associated with the posterior elastic lamina of the cornea, Duddell's membrane, now better-known as Desçemet's membrane (1758).[23]

Duddell[15] advocated removing the lens through the cornea in certain cases of cataract, usually when the lens was displaced into the anterior chamber following failed couching. In 1733, he also proposed an incision in the cornea and the anterior capsule of the lens to extract soft cataracts too difficult for couching.[19, 20, 24, 25] He incised the cornea and the capsule of the lens with the lancet he invented that was concealed in a cannula to minimise the loss of aqueous during the procedure. Subsequently, the lens was withdrawn by a hook.[20] He discussed the issue of after-cataract and argued that it was cloudiness of the anterior capsule. He also provided early descriptions of arcus senilis and sympathetic ophthalmia.[17] It is interesting to note that he used the pupil light reaction as a prognostic factor for cataract surgery, which he advised carefully:[15]I mention these things to foreworn young surgeons that they be not too rash in operating, before they well examined the case. For an eye is soon lost, and they in consequence will lose their reputation, if their want of skill occasions the misfortune’.

Duddell wrote his first treatise motivated by mistakes found in Taylor's book ‘An Account of the Mechanisms of the Eye’ (published in 1727). He disagreed with Taylor in relation to cutting corneal scars in spite of his own ‘conservative’ treatment, which included scrubbing the eye vigorously with a barley bristle brush.[15, 26] He criticised Taylor for claiming that the idea that cataract was due to opacification of the lens was a new observation, adding that it had earlier been described by Maitre Jan, Brisseau and Heister.[15] Moreover, he also answered Taylor's questions regarding the recurrence of cataract after couching.

In his treatise of 1736,[21] he described a 14-year-old boy with ‘the corneas very prominent, like obtused cones, which were sufficiently conspicuous’, which was probably an early description of keratoconus. The patient was described as an albino with nystagmus and with relatively good vision. This may be the earliest written description of keratoconus (Figure 1).

figure

Figure 1. Dr. Benedict Duddell's 1736 supplement to his treatise ‘Diseases of the Horny-coat and Cataract of the Eye and its Appendix’, which contains one of the earliest references to keratoconus

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Hirschberg[19] described Duddell as ‘a conscientious and human ophthalmologist, absolutely honest in recording his operations, rather argumentative, not only against Chesalden, but especially against Taylor whom he accuses of operating in a gross and unscrupulous manner’.

John ‘Chevalier’ Taylor

The name of John Taylor (1708–1772) is often cited when early descriptions of keratoconus are discussed. Indeed, some scholars[9, 10] give him the credit for the first description of the disease; however, often without a specific reference. The life of Taylor is described in detail elsewhere[27-30] (Figure 2). Julius Hirschberg[27] called him ‘the king among all itinerant oculists’. On the other hand, George Coats[29] (1876–1915), a well-known English ophthalmologist, who studied Taylor's life and works extensively, refers to him as ‘an unparalleled liar, pre-eminent among charlatans in the arts of advertisement; … In professional matters his knowledge was good; he was a shrewd observer and not without original ideas; but his actual practice was deeply tainted with the dishonest arts of the quack’. Uniquely, Taylor probably contributed to the blindness of two famous composers of the period, both Bach and Handel.[31, 32]

figure

Figure 2. Dr. John ‘Chevalier’ Taylor often regarded by contemporaries as a quack and charlatan provided the first accurate description of keratoconus in his works of 1766

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Taylor travelled across Europe and in places was treated with honour as the greatest ophthalmologist of his time, whereas in others he was expelled as a quack and charlatan. He was oculist to King George II and other members of royal families throughout Europe. His ophthalmic papers have been both severely criticised[27] and praised[33, 34] and they probably deserve some up-to-date review. His published works and methods of treatment were severely criticised by both Duddell and Mauchart. Two of Duddell's treatises (1729[15] and 1736[21]) were actually attacks against Taylor (vide supra). Mauchart criticised Taylor for his boasting and arrogance, although he recognised that ‘in his three publications he has reported some solid facts though they were not always his own experiences’.

It has been postulated[27, 33] that although Taylor presented some very modern ideas concerning strabismus surgery, specifically including cutting of an extra-ocular muscle,[27] tenotomy of the superior oblique, the internal rectus or division of their nerve supply,[30] he never actually performed these operations.[33] There are many descriptions of his surgery for strabismus, which appeared fraudulent.

Taylor actually described the (extra-capsular) cataract extraction before Jacques Daviel, although it is again questionable if he ever personally performed this type of cataract operation. Moreover, the first illustration of the semi-decussation of the optic nerves was published by Taylor in 1738 in his book entitled ‘La Méchanisme ou le nouveau traité de l'anatomie du globe de l'oeil’ (cited by Rucker[35]). This concept, which he seems to have understood well, was probably derived from the works of Newton or Briggs (cited by Rucker[35]).

In his two works published in 1766,[36, 37] 30 years after Duddell's (limited) first observation on keratoconus, Taylor briefly, but fairly accurately, described keratoconus, which he called ‘ochlodes’. He wrote: ‘In the second class of diseases of the cornea, the first disease in this class is when all the cornea preserve his transparency and elevate itself in a form of a cone, the point of this is obtuse (blunted) and the base occupies the entire circumference of the cornea. There is another kind of disease, where the cornea is not only high, retaining his transparency, the same as in the previous one, and similarly of a conical shape, but the point is so acute and so highten, that one at any time fears his breaking’.[37] In the other work, he described keratoconus as ‘a change in the form of the cornea by which it takes the form of a cone, whose apex is blunt, but whose base is equal to the diameter of the cornea, which preserves transparency’.[36]

Burkard David Mauchart

Mauchart (1696–1751) received a good education in Tübingen, then in Paris and Strasbourg. He returned to Tübingen and was appointed a court physician in 1723 and later (1734) a professor of the university. He taught several different fields of medicine, including anatomy, physiology, pathology, surgery, obstetrics, ophthalmology and also botany and pharmacology. For several terms of office, he was the dean of the college and the rector of the university. His publications covered all fields of medicine, especially anatomy and surgery but late in life he focused primarily on ophthalmology.[38, 39] He wrote an early treatise on ectropion,[40] in which the term ‘entropium’ was used for the first time, according to Hirschberg.[39]

It was argued that in 1748 Mauchart gave an early description of keratoconus referred to as staphyloma diaphanum;[5-8] however, the term appeared briefly in his treatise only twice: first, when he discussed different kinds of staphylomas and mentioned ‘c.diaphanum’ (probably cornea diaphanum), second when he discussed the aforementioned division in greater detail and wrote that ‘Staphyloma can be differentiated according to the colour: diaphanus if a protrusion is formed by corneal lamelae preserving its natural transparency’.[41] Mauchart knew Duddell, as they had both studied under Woolhouse in Paris and cited his works several times in his treatise. On the other hand, he disregarded Taylor's work so much that he devoted a critical paper to him.[42] Notably, Mauchart's several papers on ophthalmology were mainly devoted to corneal diseases but subsequent detailed analysis by Schleich[38] and by Hirschberg[39] make no mention of Mauchart's descriptions of keratoconus.

Keratoconus in the First Half of the 19th Century

  1. Top of page
  2. Abstract
  3. Keratoconus in the 18th Century
  4. Keratoconus in the First Half of the 19th Century
  5. Conclusions
  6. Acknowledgements
  7. References

In 1801, Scarpa described the case of a 36-year-old woman with visual deterioration with a coned, transparent cornea, the peak of which reflected the incidental light from the window ‘with such force that it appeared like a brilliantly illuminated point’.[43, 44]

Wardrop[45] devoted more pages to the description of the disorder, referencing the cases reported by other authors and analyzing the two cases he personally reviewed. He also asked for consultation by Sir David Brewster, a famous Scottish physicist, who conducted an experiment with a candle: ‘I therefore held a candle at the distance of fifteen inches from the cornea, and keeping my eye in the direction of the reflected rays, I observed the variations in the size and form of the image of the candle. The reflected image regularly decreased when it passed over the most convex parts of the cornea; but when it came to the part nearest the nose, it alternately expanded and contracted, and suffered such derangements, as to indicate the presence of a number of spherical eminences and depressions, which sufficiently accounted for the broken and multiplied images of luminous objects.’[45]

In ‘An essay on staphyloma pellucidum conicum’, Lyall[46] presented four more cases of the disorder to the Edinburgh Medical and Surgical Society.

In his ‘Encyclopedia of Ophthalmology’, Wood[47] pointed to Demours as the one who made one of the earliest descriptions of keratoconus. He wrote that ‘Demours (Traité des Maladies des Yeux, vol. 1, p.316, Paris 1818) observed the condition as early as in 1747’; however, the author of the 1818 treatise was AP Demours (1762–1836) (the son) and therefore, the observation in 1747 could have only been made by his father Pierre Demours (1702–1795) but keratoconus does not appear to be described in any of Pierre Demours' work. Interestingly, although Demours the younger mentions ‘transparent staphyloma’, his understanding of the disease may have been limited:[48]When the protuberance of the cornea or sclerotic is carried to a certain degree, it is easily recognized, but some are so not very apparent in their principle, that one sees them only with the assistance of an attentive examination. The rare transparent staphylomas of the cornea are not very appreciable when it begins, when it is recognized, by examining the eye laterally (from the side), it appears to be rather a variety of structure than the beginning of a real disease. One should not confuse with the protuberance of all the thickness of the cornea, or with the true staphyloma of this membrane, an elevation which one sometimes notices on its surface, an elevation due to an accumulation formed in its thickness …’.

In 1817, Adams[49] reported two cases of lens evacuation in patients with keratoconus, one cataract extraction and the other a clear lens extraction by ‘needling operation’ in a young woman. In both cases, he noted favourable results. Analysing the findings, he noticed that ‘the fact of the girl being capable of seeing after the removal of the lens, which was not in the slightest degree opaque, after having been blind previously, shows clearly that the refractive powers (the conical cornea and crystalline) were too powerful, and that the cure was effected by the removal of one of them’. This may have been the first surgical procedure employed in keratoconus.[50] His paper was subsequently cited by the majority of the 19th century textbooks.[1-4]

Dr William MacKenzie[51] (1791–1868), founder of Glasgow Eye Infirmary and Surgeon Oculist to Queen Victoria, devotes a little over four pages to ‘conical cornea’ in his 1830 magnum opus ‘Practical Treatise on the Diseases of the Eye’. This was the first major, comprehensive ophthalmology textbook (861 pages) written in English and it became a standard international text in various editions and translations for the next 30 years. MacKenzie fused his own clinical experience with a survey of the pertinent opinion of the time and notes Léveillé's translation of Scarpa as the first observation on conical cornea/staphyloma pellucidum.

MacKenzie[51] summarises the extant knowledge in 1830 and accurately comments on: the conical nature of the disease that the point of the cone may be less transparent ‘even nebulous or opaque’, and the cone though typically central can be to one side. He further describes at length the optical effect of the cone and surmises the effect might be akin to a normal sighted person looking through a plano-convex lens, while noting the early effect on vision is short-sightedness. MacKenzie[51] also describes in detail the candle experiment of Brewster on Wardrop's patient with conical cornea (vide supra). Thereafter, he highlights a dichotomy of opinion in 1830—either that the conical cornea was protruding and thin (Wardrop[45]) or that the protrusion was a thickening of the cornea such that the cone was solid (Adams[49]). Accurately, he further notes that the disease could occur at any time, although typically beginning around puberty, and that it often affected one eye first. Insightfully he suggests the disease was not related to elevated intraocular pressure (IOP) (the author being one of the first to note the relationship between IOP and glaucoma), nor was there any associated pain or inflammation. He suggested the aetiology was ‘an effect of some inordinate or irregular action of the nutrient vessels of the cornea itself.’[51]

MacKenzie[51] discusses some contemporary treatments he believed were unlikely to work, including concave or other glasses but points to Sir William Adams' assertion that conical cornea was due to a morbid growth of the cornea with increased short-sightedness due to increasing corneal power in conjunction with the power of the crystalline lens. MacKenzie comments that it was ‘impossible to remove the morbid state of the cornea without rendering it unfit for the transmission of light.’ He highlights that Adams had suggested removal of the lens to treat the refractive error of keratocomus and describes one of Adams' successful treatments at length (vide supra) but cautions that he is unaware of any other surgeon pursuing this approach.[51]

Thus, in his textbook of 1830, MacKenzie[51] already identifies many of the key features of keratoconus that modern eye care practitioners would recognise: a cone-shaped cornea, thinning of the cornea, apical scarring or nebulae, commencement in puberty, asymmetric but progressive disease, associated myopia, orthogonal and irregular astigmatism, an uncertain aetiology and limited correction by spectacles.

Three years later, Lawrence[52] devoted three pages to the description of the disease under the name of ‘conical cornea’ noting that the cornea ‘lost its regular convexity, and it is elevated into a conical protuberance without opacity, pain, or any preceding suffering, and without any visible change in its own texture, or in any other parts of the eye’. The patient has ‘a peculiar brilliance or dazzling look of the eye, the light being reflected in an unusual manner from the altered portion of the cornea’ and ‘when we survey the eye laterally, we see that the cornea does not present its natural convexity, that is elevated into an obtuse cone …’. Lawrence[52] noted that ‘the change in the shape of the cornea interrupts the transmission of light; the focus is altered and the patient is rendered myopic’. He also covered previous reports of keratoconus dating from Scarpa (1801) but appeared to be unaware of the earlier 18th century descriptions. Like other contemporary authors, the suggested treatment options included cataract extraction as proposed by Sir William Adams. At the end of the report, he perceptively confirmed ‘that we do not understand the pathology of conical cornea, that its causes are totally obscure, and that we know no treatment capable of remedying it’.[52]

In the contemporaneous German literature, Schmidt[53] published a treatise in 1830 solely devoted to the description of keratoconus, with an historical introduction (although he did not mention either Duddell or Taylor) and presentation of his own case. He also pointed to Guenz' 1748 dissertation[54] as the first description of the disease. A year later, von Ammon[55] described an additional case of the disorder and analysed the early description by Taylor.

In 1844, Pickford[56] published a comprehensive dissertation incorporating many earlier German and French references on the subject, beginning with the statement: ‘There is probably no disease to which the eye is subject, hitherto so rebellious to medicine, so intractable in its nature, and, at the same time, so fatal to vision, as conical cornea; and not one, the pathology and treatment of which are so little understood.’ In a well structured and insightful work, he equally eloquently notes that[56]the cornea is prolonged forwards, and presents to the observer a peculiar dazzling, sparkling point of brilliancy, a dew-drop, or gem-like radiance, as though a piece of solid crystal were embedded in its center’.

von Ammon[3, 55, 57] provided several very detailed descriptions of keratoconus. He noted that the ‘protrusion of the cornea, called as staphyloma pellucidum, has a blunt and a bit opaque tip, but the rest of the cornea is transparent. The central visual acuity is usually deteriorated, accompanied with myopia, double vision and dyschromatopsy, although there are no other eye pathologies.’ von Ammon[3] referred to studies by Schmidt under Jaeger,[53] who noticed that the cornea was ‘three times thinner than usual, resembling very thin letter paper’. He concluded with the statement that the prognosis for treatment of the disease was negative and it led to loss of visual acuity and optical illusions.

In addition to these major contributions, there were several other studies of keratoconus in the pre-Nottingham era, including reports of foetuses with conical cornea,[58-60] although these were more likely to be cases of ectasia related to congenital corneal staphyloma, rather than genuine keratoconus. Remarkably, there were only a few pictures published of the keratoconic eye, including those presented by Wardrop[45] (Figure 3) and Meller.[61] Although it has been suggested that the term keratoconus was originally introduced by Horner,[62] the earliest use of the term identified by the authors was by von Ammon in 1828.[57] Interestingly, in some later works, von Ammon[2, 63] has been correctly credited with coining the term.

figure

Figure 3. An early drawing of keratoconus by Dr James Wardrop: ‘conical formed cornea’ from Wardrop (1808)[45]

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Nottingham's practical observations on conical cornea

As highlighted in the preceding review, much was well-established in respect to the presentation, clinical features and refractive consequences of keratoconus before 1850; however, the exhaustive 270-page treatise by John Nottingham[64] in 1854 (Figure 4) has been widely recognised as the first work to fully consolidate and distil the disparate strands into a modern, comprehensive understanding of keratoconus. Nonetheless, Nottingham[64] personally recognised his indebtedness to his predecessors in the field, noting in the preface, ‘Especial mention should be made of the original observations of Dr Pickford, of the late Mr Walker of Manchester, of Mr Middlemore and Mr Gervis, of the valuable monograph on conical cornea of Mr W.W. Cooper (not to mention the many names of equal merit in France, Germany, and Italy. …) and last but not least, of the profound work of Stellwag von Carion, and the methodic and beautiful treatise of the brilliant Cappelletti.’

figure

Figure 4. The frontispiece of Dr John Nottingham's 1854 landmark publication on ‘Practical Observations on the Conical Cornea’

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Conclusions

  1. Top of page
  2. Abstract
  3. Keratoconus in the 18th Century
  4. Keratoconus in the First Half of the 19th Century
  5. Conclusions
  6. Acknowledgements
  7. References

This brief review highlights early 18th and 19th century descriptions of keratoconus, which are poorly recognised by modern eye-care professionals. This confirms, as is so often the case, that studying historical papers often reveals unknown or forgotten earlier descriptions of diseases, sometimes believed to be discovered by modern medicine. This study also corrects some of the erroneous historical statements, descriptions and references commonly cited in past and current articles on keratoconus. It also highlights that although there was no understanding of the pathogenesis of the disease, the clinical description in some of the early papers described was reasonably accurate.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Keratoconus in the 18th Century
  4. Keratoconus in the First Half of the 19th Century
  5. Conclusions
  6. Acknowledgements
  7. References

The authors wish to thank Dr Robert Heitz for his help in translation from French to English, Dr Katarzyna Surdyk for her help in translation from Latin to Polish and Professor David Taylor FRCOphth and Mrs Lilly Vekerdy (Rare Books Collection, Smithonian Library, Washington) for helping to access Duddell's textbooks. Ms Maree McInerney, New Zealand National Eye Centre, accessed Nottingham's treatise and other works.

References

  1. Top of page
  2. Abstract
  3. Keratoconus in the 18th Century
  4. Keratoconus in the First Half of the 19th Century
  5. Conclusions
  6. Acknowledgements
  7. References
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