[NOTE: This paper was written in Spring 2017, and in the absence of updates may no longer accurately reflect an up-to-date understanding of Coats’ disease. It is intended as a historical study rather than a medical resource. Links to further information regarding Coats’ disease are included below.]

George Coats was born on March 5, 1876 in Paisley, Renfrewshire, Scotland, the youngest child of eight surviving to Allan and Isabella Coats. His father was a second-generation ham curer who together with his older brother, William, operated the coal and butchery shop their father had run before them. Business was sufficiently brisk to pay for a detached villa in Paisley’s affluent Castlehead district, and to allow Allan’s four sons to pursue educations. Allan’s youngest brother, Joseph, was a pathologist and lecturer in nearby Glasgow, whom George alone would follow into medicine. After enrolling at Glasgow University in 1892, George Coats would finish first in his class in pathology and surgery and graduate in five years with bachelor degrees in medicine and surgery. He earned his MD in 1901 following residency at the Royal, Western, and Eye Infirmaries in Glasgow, writing his graduate thesis on hemorrhagic retinitis. Having decided by that time to pursue ophthalmic surgery, he trained for an additional year in the ophthalmic clinic of Vienna, while undertaking a cycling tour of similarly prestigious clinics in Munich, Freiburg, and Zurich. He returned to the United Kingdom in 1902 and settled in London, where he would spend the remainder of his life, practicing surgery and pathology at several of London’s largest hospitals. He was active in research throughout his career, building all the while on the interest in hemorrhagic and exudative diseases of the retina that had formed the basis of his thesis. His first paper, in 1904, dealt with central retinal vein thrombosis, while his last, published 11 years later, covered lymphoid infiltration of the orbit.

Coats died on November 2, 1915, aged 39, one week after an abdominal operation intended to relieve an unspecified chronic illness that had made it difficult to work for four or five years. Despite these obstacles, he was renowned amongst his colleagues for his work ethic: at least five contemporary obituaries refer to his insatiable academic curiosity, a reputation borne out by the 75 articles Coats produced in the 11 years he produced original research. (He additionally was sole author on all but 11 of these papers.) While Coats was held in high regard by his colleagues from nearly the beginning of his career – having been admitted to the Fellowship of the Royal College of Surgeons in 1903 – it was his research that made him famous within ophthalmology. On this basis, he was named Hunterian Professor of the Royal College of Surgeons in 1910, given the Ophthalmological Society’s Nettleship medal and prize in 1912, and elected to leadership positions in the Ophthalmological Society and Royal Society of Medicine’s ophthalmology section. Most significant among the honors bestowed during his lifetime, though, was the near-universal adoption of the eponym which would serve as his greatest legacy.

In introducing his first of two seminal papers outlining the condition that would soon bear his name, George Coats described an “undoubtedly rare” disease, but ventured that already “most ophthalmic surgeons [would] recall having seen something of the kind.” Coats was uniquely qualified to conceptualize this cluster of already-recognized symptoms as a unified disease entity. At the time, patients who would years later be recognized to have Coats’ disease were often diagnosed with suspected intraocular tumors, typically leading to enucleation. As one of London’s leading pathologists – and perhaps the only retina specialist among them – Coats was pleased to examine specimens provided by every other surgeon in his professional network, in addition to those taken from his own patients. The aforementioned paper, titled “Forms of Retinal Disease with Massive Exudation,” was a 85-page-long manifesto analyzing 6 of these pathological specimens and nearly 60 case reports which seemed, to Coats, to fulfill the same diagnostic criteria. Coats’ follow-up paper in 1912 was published in von Graefe’s Archiv für Ophthalmologie, at that time the most prestigious journal in his field; it, too, focused on the pathological hallmarks of the disease. Reflecting on these papers in an obituary, Leslie Paton remarked that despite a need for continued elucidation of the disease’s etiology and clinical course, “Coats’s work leaves practically nothing to be added to our knowledge of its pathology.”

As evidenced by his eventual publication in Graefe’s Archive, Coats’ work was of considerable interest in Germany, at that time the center of the ophthalmological world. Case reports written by Coats (including those on exudative retinitis) are cited in Archive papers as early as 1905. Likely the earliest published use of the eponym, however, came in a 1913 anatomical case report by the famed ophthalmologist Eugen von Hippel. Having compared his patient’s exudative retinitis to others found in the literature, von Hippel comments that “the main interest of the case” lies in whether or not it can be considered an early-stage example of “the Coatsian disease” [Coatsschen Erkrankung], “or whether it has nothing to do with it.” He further notes that this ambiguity was consistent with the contemporary understanding of the disorder, citing Coats’ warning that it was “not at all certain to decide whether [his] observations… represent a uniform clinical picture.”

Ambiguity, in fact, persisted for decades, with one 1955 case report on subretinal masses including Coats’ disease in the differential diagnosis, yet describing it as a “poorly defined symptom complex.” Part of the confusion lie in Coats’ uncertainty as to which entities were true “exudative retinitis,” a question he was unable to answer in the three years between his Graefe’s Archive paper and his death. Coats’ 1908 paper proposed three categories of patients under the newly-defined illness: those without vascular abnormalities, those with marked vascular changes, and those with arteriovenous communications. By 1912, Coats had refined his understanding of the disease and omitted disease categories. Critically, the erstwhile third group was found by von Hippel to be a separate disease entity, angiomatosis retinae (now named retinal hemangioblastoma). Concurrent to Coats’ second paper was one by Theodor von Leber describing a group of young male patients who displayed the unilateral telangiectasias and aneurysms described by Coats in 1908, but lacked the subretinal exudation that had given Coats’ first paper its title. Leber suggested in this and subsequent papers that these patients were likely in the early phases of the disease described by Coats. This cluster of symptoms was nonetheless held to be a separate disease entity, known as Leber multiple miliary aneurysms with retinal degeneration, until a case of definitive progression from Leber’s disease to Coats’ disease was published by Algernon Reese in 1956, formalizing its inclusion into the diagnosis.

With these entities at last disentangled, refinements of our understanding of the disease have been sporadic. In 1912, Coats had suggested that the vascular disease underlying exudative retinitis might have been “of a type which cannot be recognized by the ophthalmoscope itself, not by our present microscopic methods.” 44 years later, in addition to solving the question of Leber’s disease, Reese demonstrated thickened, PAS-positive capillary basement membranes in the retina. These structural abnormalities were postulated to limit retinal blood flow, triggering the characteristic vascular proliferation and exudation of Coats’ disease. The extent to which retinal architecture was disrupted emerged in 1971, when electron microscopy demonstrated changes including replacement of the endothelium and pericytes of vessel walls with a laminated, fibrous coating of basement membrane-like material. With novel microscopic findings effectively exhausted, contemporary advancements in our understanding of Coats’ disease are genetic in nature. Though multiple loci have been implicated, it is currently believed that a mutation in the Norrie disease pseudoglioma gene causes a Norrin protein deficiency, leading to malformations and unchecked proliferation in retinal vasculature.

George Coats’ final statement on Coats’ disease came in the summary of his 1912 article. He wrote that it was possible to “differentiate a disease of the retina,” characterized by prominent collections of exudates under the retinal vessels, with or without visible vascular disease on fundoscopic exam. This disease occurred primarily in healthy young men. The course was insidious, could wax and wane, and in relatively few cases could lead to loss of the eye secondary to “retinal detachment, secondary cataract, iritis, pressure loss, or glaucoma.” The pathology was characterized by chronic inflammation and scarring that progressed from the outer retinal layers into the subretinal space. Though the ultimate etiology was unclear, “the theory of local vascular disease seem[ed] to offer fewer difficulties than any other.” More than a century of subsequent progress has excluded retinal hemangioblastoma from, and included Leber’s disease into, the diagnosis; detailed the microscopic events underlying the observed vasculopathy; and elucidated the genetic abnormalities responsible.

Coats’ disease is otherwise understood in much the same way it was by the colleagues that survived its namesake.

* * *

J. Herbert Parsons was an ophthalmic surgeon, and one of nine practitioner-researchers to have appeared as a coauthor in Coats’ work. His office stood two doors east on Queen Anne Street from that of George Coats, and only 3 blocks from his Marylebone flat. It was perhaps this proximity that helped include Parsons among the few, he wrote in an obituary, whom Coats “admitted… into the intimacy of his friendship.” Parsons described a quiet man with two noteworthy extramedicinal interests: music and history. Discussing the latter, he references a paper Coats had recently contributed to the Ophthalmic Hospital Reports on the life and times of “the famous quack ‘Chevalier’ Taylor,” whose “vagaries… were obviously a source of amusement to the author.” While Parsons suitably called attention to an important addition to his friend’s bibliography, his words rather undersell the scope of the project: not only is Coats’ biography of Taylor 92 pages long, it was supplemented in the following issue with an additional 27 pages of historical research, including separate biographies of Taylor’s son and grandson! This thoroughness is the common bond linking each item in Coats’ body of work – from medical history to veterinary retinal pathology – and is surely what enabled him to uncover or predict nearly every detail relevant to his work outside of the discovery of DNA and birth of genetics. The life story and work of George Coats are inextricable from our understanding of his disease, and it’s only fitting that in an era of fading eponyms, his should be one of the last left standing.

Works Cited

• Coats G. “The Chevalier Taylor.” The Royal London Ophthalmic Hospital Reports May 1915; 20 (1): 1-92.

• Coats G. “Forms of retinal disease with massive exudation.” The Royal London Ophthalmic Hospital Reports Nov 1908; 17 (3): 440-525.

• Coats G. “Historical Notes.” The Royal London Ophthalmic Hospital Reports Mar 1916; 20 (2): 129-156.

• Coats G: “Über Retinitis exsudativa (Retinitis haemorrhagica externa).” Albrecht von Graefes Archiv für Ophthalmologie 26 Mar 1912; 81 (2): 275-327. Translation via Google Translate.

• Egerer I, Tasman W, Tomer TL. “Coats Disease.” Archives of Ophthalmology Aug 1974; 92 (2): 109-112.

• Frayer WC. “Coats’ Disease: A Clinical and Pathologic Study.” AMA Archives of Ophthalmology Aug 1955; 54 (2): 240-244.

• Knapp A, Hess C, Holden WA, Eds. “Obituary.” Archives of Ophthalmology 1916; 45 (1): 108.

• Morris B, Foot B, Mulvihill A. “A population-based study of Coats disease in the United Kingdom I: epidemiology and clinical features at diagnosis.” Eye 2010; 24: 1797-1801.

• The National Archives of the UK: Census for England, Scotland, and Wales, 1851, 1861, 1871, 1881, 1891, 1901, and 1911.

• “Obituary. George Coats, M.D. Glasg., F.R.C.S. Eng.” The Lancet 13 Nov 1915; 186 (4811): 1110-1111.

• Parsons JH. “The Late Mr. George Coats.” The Lancet 20 Nov 1915; 186 (4812): 1161-1162.

• Paton L. “Obituary. George Coats, M.D., F.R.C.S.” The Ophthalmic Review 1915; 34: 359-365.

• The Post Office London Directory for 1816. London: Kelly’s Directories Ltd., 1916. Trades Directory, 1873.

• Reese AB. “Telangiectasis of the retina and Coats’ disease.” American Journal of Ophthalmology July 1956; 42 (1): 1-8.

• Ryan SJ, Sadda SR, Hinton DR, Schachat AP, Wilkinson CP, Wiedemann P. Retina. 5th ed. [London?]: Saunders, c2013. Chapter 56, Coats’ disease; 1058-1070.

• Stephenson S, Ed. “Notes and Echoes: Deaths.” The Ophthalmoscope 1915; 13: 634-637.

• Tripathi R, Ashton N. “Electron microscopical study of Coat’s disease.” British Journal of Ophthalmology May 1971; 55 (5): 289-301.

• von Hippel E. “Anatomischer Befund bei einem Falle von Retinitis exsudativa (Coats).” Albrecht von Graefes Archiv für Ophthalmologie Oct 1913; 86 (3): 443-456. Translation via Google Translate.

• von Hippel, E. “Angiomatosis retinae und Retinitis exudativa (Coats).” Albrecht von Graefes Archiv für Ophthalmologie 23 Sept 1931; 127 (1): 27-56. Translation via Google Translate.

• Wise GN. “Coats’ Disease.” AMA Archives of Ophthalmology Nov 1957; 58 (5): 735-46.

George Coats’ Bibliography

George Coats was a prolific author who published nearly 1300 pages of novel research in only 11 years. This does not include reviews of scientific books and articles that he contributed to multiple journals during that time (most notably The Ophthalmoscope and Opthalmic Review); these short additional contributions number in the dozens to hundreds, and between them constitute a substantial body of work in their own right. Below is a chronological complete list of the 75 major articles written by George Coats between 1904 and 1915. It is adapted from the obituary written by Leslie Paton [“Obituary. George Coats, M.D., F.R.C.S.” The Ophthalmic Review 1915; 34: 359-365], with several key corrections.

1904

“Thrombosis of the central vein of the retina.” The Royal London Ophthalmic Hospital Reports 16 (1).

“A case of thrombosis of the central vein pathologically examined.” Transactions of the Ophthalmological Society of the United Kingdom 24.

1905

“The structure of the membrane of Bruch and its relation to colloid excrescences.” The Royal London Ophthalmic Hospital Reports 16 (2).

“Obstruction of the central artery of the retina.” Ibid, 16 (3).

“A case of tubercle of the nerve head.” Ibid.

“Sections of an eye with pieces of wood in it.” Transactions of the Ophthalmological Society of the United Kingdom 25.

“Peculiar appearance of a retinal vein.” Ibid.

“Congenital abnormalities of retinal vessels in two sisters.” Ibid.

1906

(With J. H. Parsons) “A case of orbital encephalocele with unique malformations of the brain and eye.” Brain 114.

“Case of Conjunctival Growth shown by Mr. E. J. Smyth at the last Meeting. Notes on the Pathology.” The Ophthalmic Review 25.

“On the pathology of chorio-vaginal veins.” Ibid.

(With A. Lawson) “Sections of a Case of Congenital Anterior Staphyloma, previously shown by Mr. Lawson.” Ibid.

(With J. H. Parsons) “Pathological Report on a Case of Orbital Encephalocele associated with Microphthalmos, shown before the Society in 1905.” Ibid.

“Posterior scleritis and infarction of posterior ciliary arteries.” Ibid.

“Intraocular vascular disease.” The Ophthalmoscope 4 (11).

“Further cases of thrombosis of the central vein.” The Royal London Ophthalmic Hospital Reports 16 (4).

(With A. Lawson) “Further history and pathological examination of a case of congenital anterior staphyloma previously shown by Mr. Arnold Lawson.” Transactions of the Ophthalmological Society of the United Kingdom 26.

(With A. S. Morton) “A Case of subconjunctival cysticercus.” Ibid.

1907

“The pathology of macular holes.” The Royal London Ophthalmic Hospital Reports 17 (1).

“An unusual form of cyst of the iris.” Ibid.

“The pathology of ruptures of the membrane of Descemet.” Transactions of the Ophthalmological Society of the United Kingdom 27.

“Posterior scleritis and infarction of the posterior ciliary arteries.” Ibid.

“A case of oxycephaly.” Ibid.

1908

“The pathology of coloboma at the nerve entrance.” The Royal London Ophthalmic Hospital Reports 17 (2).

“Congenital pigmentation of the papilla.” Ibid.

“Forms of retinal disease with massive exudation.” Ibid., 17 (3).

(With J. B. Lawford) “A case of primary extradural tumour of the optic nerve.” Transactions of the Ophthalmological Society of the United Kingdom 28.

“Varicose veins of the conjunctiva.” Ibid.

1909

“On the occurrence of misplaced derivatives of the secondary optic vesicle in congenitally abnormal eyes.” Ibid., 7 (11).

1910

“A case of microphthalmos with remarks.” The Ophthalmoscope, 8 (10).

(With R. J. Coulter) “Teratoma of orbit.” The Royal London Ophthalmic Hospital Reports 18 (1).

1911

(With W. I. Hancock) “Pathological examination of the freshly fixed eyes from a case of amaurotic family idiocy.” Brain 30 (3).

“A case showing enlargement of the anastomoses about the nerve entrance.” The Ophthalmic Review 30.

“A case of exudative retinitis.” Ibid.

(With J. G. Forbes) “On the relation of the meningococcus intracellularis to pseudoglioma.” Proceedings of the Royal Society of Medicine Pathological Section 4.

“Hernia and rupture of the early lens vesicle.” The Royal London Ophthalmic Hospital Reports 18 (2).

“The lacrimal ducts in a case of cyclopia.” Ibid.

“Pathological Examination of the Specimen from a Case of Marginal Keratectasia Previously Shown by Mr. J. Herbert Fisher.” Transactions of the Ophthalmological Society of the United Kingdom 31.

“An unusual instance of colloid excrescences of the membrane of Bruch.” Ibid.

“Atypical coloboma of the iris and lens with persistent mesoblastic strand.” Ibid.

(With F. G. Thomas) “A peculiar granuloma of the retina.” Ibid.

1912

“Über Retinitis exsudativa (Retinitis haemorrhagica externa).” Albrecht von Graefes Archiv für Ophthalmologie 81 (2).

“Discussion on chronic iridocyclitis.” British Medical Journal 2 (2703). [Part of “Eightieth Annual Meeting of the British Medical Association”]

“Three tumours arising in sweat glands.” The Royal London Ophthalmic Hospital Reports 18 (3).

“Papilloma and sebaceous adenoma of the caruncle.” Ibid.

“Local metastasis in intraocular sarcoma.” Ibid.

“Two cases showing small superficial opaque white rings in the cornea.” Transactions of the Ophthalmological Society of the United Kingdom 32.

“Concretions in the papilla and corpora amylacea in the retina.” Ibid.

“Tubercle of the choroid in a cat.” Ibid.

“On crystal-like bodies (? leucin) in the lens.” Ibid.

“Unilateral diffuse melanosis of the uvea, with small elevations on the iris.” Ibid.

“Pigmented cyst lying free in the anterior chamber.” Ibid.

1913

“Der Verschluss der Zentralvene der Retina.” Albrecht von Graefes Archiv für Ophthalmologie 86 (2).

“Anterior ring of opacity in the lens following a contusion (Vossius’s contusion ring).” The Ophthalmic Review 32.

“Iridocyclitis with special reference to pathology.” Ophthalmology 9 (2).

“Infarction of posterior ciliary arteries.” Ophthalmoscope 11.

“Some instances of disease in the animal eye.” Proceedings of the Royal Society of Medicine Ophthalmology Section 7.

“Small superficial white rings on the cornea.” Ibid.

“Pathology of obstruction of the central artery of the retina.” The Royal London Ophthalmic Hospital Reports 19 (1).

“On the preservation of visual field after obstruction of the central artery of the retina.” Ibid.

“Visible anastomoses on the papilla after obstruction of the central artery.” Ibid.

“On pathological aspects of retinal vascular disease.” Transactions of the Ophthalmological Society of the United Kingdom 33.

1914

“Abnormal course of a retinal vein.” Ophthalmoscope 12.

“Two instances of congential abnormality in the dog.” The Royal London Ophthalmic Hospital Reports 19 (3).

• “Congenital central cataract in two fox-terriers belonging to one litter.”

• “Bilateral failure in the separation of the pupillary membrane from the cornea and partial albinism in a bull-terrier.”

“Traumatic rupture of the pigment epithelium and dilatation of the iris.” Transactions of the Ophthalmological Society of the United Kingdom 34.

“Congenital partial paralysis of the oculomotor nerve, with cyclical contraction and dilatation of the pupil.” Ibid.

1915

“Lymphoma and lymphosarcoma of the conjunctiva.” Archives of Ophthalmology 44.

“Discrete lymphoid infiltration of the orbit.” Ibid.

“A peculiar form of retinal atrophy in the dog.” Ophthalmoscope 13.

“The Chevalier Taylor, a famous eye quack.” The Royal London Ophthalmic Hospital Reports 20 (1).

“Hyperplasia, with colloid and amyloid degeneration, of the episcleral and circumdural fibrous tissue.” Transactions of the Ophthalmological Society of the United Kingdom 35.

“The choroid and retina of the fruit-bat.” Ibid.

(With Lieut.-Colonel W. G. Pridmore) “Demonstration of a filaria from the eye of the horse.” Ibid.

“A parasite in the eyelid of the mouse.” Ibid.

1916

“Historical Notes” The Royal London Ophthalmic Hospital Reports, 20 (2). [Published posthumously]

• “The Chevalier Taylor’s Son.”

• “Some early observations on the restoration of sight in the congenitally blind.”

• “Roger Grant.”

• “The Chevalier Taylor’s grandson.”