How to Classify, Teach, and Learn Ophthalmic Eponyms

Introduction There are limited educational studies on effective ways to teach and learn medical eponyms. While there is no consensus on how to best address this issue, developing novel strategies to teach medical eponyms has become critical in many branches of medicine, including ophthalmology. Materials & Methods An ophthalmologic eponymic database was created using eight source texts (e.g., books, encyclopedias, and dictionaries) and included the year the eponym was introduced, related name, nationality, specialty, and the eponym’s description. PubMed database with a Medical Subject Headings (MeSH) keyword for “eponym” and “eye” and “ophthalmology” and a Google search for a combination of related keywords was also performed. A careful biographical search was conducted for each name in the second phase to obtain further biographical details. Inclusion criteria for eponyms in the dataset were: i) named after at least one person, ii) identified as a specific medical term in the literature, iii) related to any field of medicine. Names derived from art, history, mythology, patient, family, chemistry, botany (or other fields outside of medicine) were excluded. The three authors independently screened to eliminate duplicated names and ensure eligible names met inclusion and exclusion criteria. Results A total of 1,257 unique ophthalmologic eponyms representing 8.8% of 14,332 medical eponyms were identified. Three-hundred fifty-one of 743 (47.2%) eponyms were named after ophthalmologists representing 36 countries. The United States of America and Germany comprised the largest fraction of nationalities (40.2%), not necessarily representing their birthplace. Signs, syndromes, and diseases composed the largest category (45.8%) of eponymous ophthalmologic names. Discussion The current volume of eponymous names impedes the ability of a learner to retain this information. Classifying eponyms based on form, intention, or function, provides a more refined method for placing eponyms in their respective categories. Teaching eponyms by enumerating their historical content, demonstrating the correct performance of the eponym, assessing the technique, and providing feedback, affords the learner a more fruitful and meaningful learning experience. Understanding the context of the signs, syndrome, or techniques further allows the learner to gain insights into the clinical application of eponyms in diagnostic decision-making. Conclusion The teaching model proposed incorporates key aspects that may facilitate retention and recall of the eponymous name. The model includes imparting historical knowledge about the person who described the sign, technique, or process; demonstrating the correct procedure as originally reported; and coaching to ensure that the appropriate skill is mastered. Before abandoning eponyms, it is first necessary to understand their efficacy, effectiveness, usefulness, and role in clinical medicine.


Introduction
Eponyms provide a rich cultural perspective to the literature and remind us about our historical medical heritage. Despite this, the routine use of eponyms remains controversial, with not all physicians embracing their widespread use [1][2][3]. Unfortunately, ophthalmologic eponyms have not been well studied, and there is a paucity of information available for only a few eponyms in clinical medicine [4,5]. Before abandoning eponyms, it is incumbent that we further study them in order to determine their reliability, validity, and applicability in clinical practice. Eponyms found to be valid should be further classified, based on expert advice within the various subspecialties, to facilitate teaching and learning. This paper aims to formulate and propose a teaching model that provides a meaningful way for classifying and teaching ophthalmological eponyms. We recognize gaps in our knowledge about how to teach eponyms as there are limited studies available. Furthermore, the principles applied to the ophthalmologic literature are also applicable to other specialties of medicine.

Materials And Methods
Data were obtained from research utilizing primarily eight sources representing medical or eponymic books, dictionaries, encyclopedias, indexes, medical periodicals, and one online source. The following criteria were considered in selecting eponyms: i) the eponym should be named after at least one person, ii) the eponym should be identified as a specific medical term in the literature, and iii) the eponyms should be related to any field of medicine. Names derived from art, history, mythology, patient or family names were excluded from the list identified. Moreover, eponymic names related to chemistry, biology, botany (or other fields outside of medicine) were also excluded.
In the first phase, an eponymic database was created. The eight sources were scanned by one of the authors (Halil Tekiner), identifying names, year introduced, related name, nationality and specialty, and the eponym description. The PubMed database was searched with a Medical Subject Headings (MeSH) keyword for "eponym" and "eye" and "ophthalmology" in humans published from inception to June 1, 2021. A Google search for a combination of related keywords was also performed to find any other names not appearing in text sources. A biographical search was conducted for each name in the second phase to obtain further biographical details. Obituaries were extremely helpful in this regard. For those names whose gender was not apparent, a photographic search was also conducted. The three authors independently screened to eliminate duplicated names and ensure eligible names met inclusion and exclusion criteria.
This type of research has its limitations. Despite our efforts, it is inevitable to have several names missed in this list or the derivation undetermined, especially those known only with their surname or the initial letters of their names. Therefore we cannot claim this list is precisely complete in its current form.

Results
We identified and classified 1,257 (8.8%) unique ophthalmologic eponyms representing 14,332 total eponyms in the eponymous literature [6][7][8][9][10][11][12][13]. We created eight categories within this classification schema as this would limit the number of categories making it easier to manage and learn. Each eponym was assigned to a single category to avoid overlap, even though some fit into more than one. For example, Westphal pupillary reflex is both a clinical and physiologic phenomenon but was assigned to the clinical one, as it is more relevant to a practicing physician. Categories were arranged based on common themes. The category algorithm, classification, formula, theory, and law all involve problem-solving techniques. Clinical symptoms are objective or subjective findings or phenomena. Pathologic findings were grouped with clinical symptoms as they represent the histopathologic component to an objective or subjective condition. The words device, instrument, product, and supply are in reference to a larger category named tools, as a device may be an instrument or equipment, and an instrument is a device. With this exception, all the remaining eponyms received one qualifier within a category.
Signs, syndromes, and diseases represented the largest category at 576 (45.8%), followed by those including devices, instruments, medical products and supplies at 260 (20.7%), clinical/pathological aspects of disease at 185 (14.7%), techniques at 127 (10.1%), and other subcategories ( Table 1).  of these are names honored men, reflecting the preponderance of men in this specialty before the midtwentieth century. Interestingly, the nationality of these individuals, not necessarily the country from which the eponym was written, were American (20.9%), German (19.3%), and Austrian (10.2%); followed by French (9.8%), Swiss (7.6%), and English (7.1%) among many others.

Discussion
Eponyms used in the context of clinical medicine are honorific terms bestowed to an individual(s) who identified or discovered a disease, sign, symptom, syndrome, test, or finding. They may also represent a designation of an anatomical structure, devices, procedures or techniques, views or phenomena, treatments, classifications or indexes, prediction rules, laws or principles, or algorithms. Eponymic signs and findings are rarely pathognomonic by themselves. When used in combination with other symptoms, signs, and physical findings, it assists in diagnosis. Their use should be strictly reserved to honor individuals whose contribution(s) embody the rich tradition of the art of medicine for centuries.
There are drawbacks to the use of medical eponyms, which have led to reservations regarding their use. Limitations with eponyms include inaccessibility of the original publication or presentation because it was written in a different language or presented at a conference or in a monograph, historical misinformation, lack of attribution of all authors, naming (e.g., misspelled, a middle name used, multiple renditions of surname, and the same name which may have different meanings), and transcription challenges from non-Latin scripts such as Arabic, Greek, and Russian or sometimes from umlaut letters (ä, ö, ü) in the extended Latin alphabet. Other issues regarding eponyms are the routine use by authors of the possessive form of the name and inclusion within the literature of eponymic names derived from individuals who committed atrocities against humanity or bore racist or antisemitic remarks. The latter has improved as of more recent times as there has been increased awareness and confirmation of these claims. As a result, diseases were renamed and replaced with more descriptive terms (e.g., Wenger granulomatosis to granulomatous with polyangiitis or Reiter syndrome to reactive arthritis). The possessive form of the eponymous name continues to be used in the literature even though its use should be restricted to cases whereby the person had the sign, disease, or syndrome for which they described. The most highly recognized example of where the possessive form is an acceptable designation is Trousseau's sign named for Armand Trousseau (1801-1867), who developed phlebitis occurring in association with a gastric tumor [14].
It is unrealistic to think that hundreds of ophthalmologic eponymic names could be taught, processed, remembered, and recalled. This is compounded in that many eponymous names having more than one designation in the same category. Furthermore, it may not be recognized that an eponym may also be named for both a father and son, as in Sturge-Weber syndrome or von Hippel-Lindau disease. Several papers recommend standardizing terminology when naming new and existing morphological abnormalities and new diseases that can also be applied when classifying ophthalmologic eponyms [15][16][17]. This serves as the basis for assisting in identifying the framework for naming eponyms. The critical designations to consider are that eponyms be limited to one proper name and no more than three names with the last name(s) used, and authorship preferably limited to include those in the first three positions of the manuscript or monographs. Initials and acronyms [(e.g., acute retinal necrosis (ARN), congenital hypertrophy of the retinal pigment epithelium (CHRPE), and acute posterior multifocal placoid pigment epitheliopathy (APMPPE)] should be avoided. Eponyms that are currently obsolete (e.g., Donder glaucoma, Donder ring, Doyne honeycomb choroidopathy, Filatov operation) should be excluded from ophthalmologic terminology.
Despite these limitations, which apropos constitute a small portion of the eponymous corpus, we believe that eponyms should be retained and further studied unless there is compelling evidence to the contrary. We concur with the words of Sir Gordon Gordon-Taylor (1878-1960), a pioneering British surgeon and past President of the Royal Society of Medicine, "This may sound antiquated, but it goes against me to sacrifice names which for centuries have proved to be good and useful. The honorable names of our science are thereby fixed in the memory of posterity, and through them, there is awakened in the student a certain historical interest which stimulates him to further investigation" [18].
The field of ophthalmology is replete with eponyms that have been assigned to nearly every conceivable structure within the eye or as part of a systemic process that secondarily involves the eye. Interest in eponyms is likely to grow in recent years, with many journals publishing articles on ophthalmologic eponyms such as Eales disease and Sjögren syndrome or eponyms named to honor female ophthalmologists [19][20][21][22].
Clarifications regarding eponyms and their clinical applications can only come about through further studies that examine their validity, reliability, and reproducibility. Physicians make cognitive errors in clinical decision-making that involve biases and heuristic shortcuts. This may be further perpetuated based on anchoring and premature closure, which leads physicians astray from identifying the correct diagnosis.
Other errors are linguistic, based on a physician's lack of knowledge regarding the meaning of a structure, process, disease, symptom, syndrome, or sign. These failures include physician's inability to distinguish Bell (Charles Bell, 1774-1842) palsy as idiopathic facial nerve paralysis from other known causes of peripheral facial nerve paralysis, or that William John Adie (1886-1935) described the findings of areflexia found predominantly in women with a known tonic pupil and thus constitutes a syndrome (Adie syndrome), a constellation of signs, symptoms, and findings, "All the evidence seems to me to support the notion that the tonic convergence reaction in pupils apparently inactive to light is a thing apart. The peculiar extra-ocular phenomena (symptomless areflexia) that are frequently associated with it also suggests that we are confronted by a unique condition" [22]. Therefore, it is incumbent that educators teach these principles to learners to avoid perpetuating the same errors. The question is, what the best method for teaching eponyms is?
Disease, syndromes, and signs will continue to become better defined as they are studied, leading to, in some cases, a more refined and specific disease classification. Eponymically named signs and syndromes by themselves lack sufficient specificity alone for diagnostic purposes. In most cases, they represent only the anatomic (e.g., Leber venous plexus), physiologic (Donder law), or pathologic (e.g., Fuch adenoma) expression of the disease or algorithm (e.g., Helvacioglu reproducibility index), classification (e.g., Mann), theory (e.g., Elschnig), or formula (e.g., Reuss). These eponymic signs, syndromes, findings, devices, and techniques, when used in some cases in combination with other more sophisticated diagnostic tests, assist in better understanding, sorting out, and sorting through, the various disease processes.
Classifying ophthalmologic eponyms based on a mechanistic approach assists the reader to understand better their representation (e.g., anatomic, pathologic, physiologic) and purpose (e.g., test, technique, algorithm, classification, instrument, or device, or operative technique), as shown in Table 2.

Name Eponym Classification
Adie    We propose a learning model that involves teaching historical aspects of the person(s) who described the sign, the signs as originally described, and its application, if available, in medical practice. Teaching history imparts purpose to the eponym and, in some cases, a more in-depth understanding of the process or steps involved in identifying the particular finding. Teaching the finding as described by the author avoids misattribution or communication errors. Lastly, the application of the finding in clinical practice should be covered, incorporating known and evolving techniques and technologies to understand the disease or disease process better.
To the best of our knowledge, only one recent study evaluated a method for teaching eponyms. Viveen et al. assessed knowledge involving ten common eponymous questions before and after a two-day course among 20 orthopedic trauma surgeons in an Arbeitsgemeinschaft für Osteosynthesefragen (Swiss working group for bone fusion issues) advanced trauma course on complex elbow fractures [23]. The eponym questions covered the areas of surgical techniques, fracture types, injury, and pathologic findings. The training involved didactic and cadaveric sessions. In order to prevent bias, no emphasis was placed on the eponyms, and participants were unaware of the nature of the study. The study found that correct answers about the eponym improved in only one question with inter-rater reliability (Kappa score) of 0.31 and 0.37 before and after the course, respectively [23]. Findings from this limited study suggest that this is an ineffective method for teaching eponyms.
We believe that eponyms are interesting to learn, and information about them should be retained and taught using an evidence-based approach. When teaching eponyms, we recommend that the components include a brief historical perspective of the person who described the sign, its original description, and its application in clinical practice. The teacher should explain and, in some cases, demonstrate the proper performance of the eponym and its application in clinical practice. The eponym should be practiced with feedback provided, and in the case of eponyms involving signs, their utility in assisting in diagnosis be emphasized [5,24].

Conclusions
Teaching and learning eponyms in the context of a historical perspective and, as described by the author, tells a story using a case-based learning applied model approach. This way of learning provides a meaningful way best to understand the application of eponyms in clinical practice. There is a continued impetus to remove eponyms and to substitute them using more descriptive terms. Although we do not favor this approach, we emphasize that eponyms must first be studied before devoting time to this endeavor to determine their effectiveness in clinical medicine. Those eponyms deemed to have utility in clinical practice should be retained and classified using predetermined criteria.

Additional Information Disclosures
Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue.

Conflicts of interest:
In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.