Ophthalmology
From Wikipedia, the free encyclopedia
Ophthalmology is the branch of medicine which deals with the diseases and surgery of the visual pathways, including the eye and brain. The word ophthalmology comes from the Greek roots ophthalmos meaning eye and logos meaning word; ophthalmology literally means "The science of eyes." As a discipline it applies to animal eyes also, since the differences from human practice are surprisingly minor and are related mainly to differences in anatomy or prevalence, not differences in disease processes. By convention the term ophthalmologist is more restricted and implies a medically trained specialist. Since ophthalmologists perform operations on eyes, they are generally categorized as surgeons.
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[edit] History of ophthalmology
The eye, including its structure and mechanism, has fascinated scientists and the public in general since ancient times.
Sushruta wrote Sushruta Samhita in about 5th Century BC in India, describing about 72 diseases of the eye, description of fine ophthalmological surgical instruments & eye surgery and is described as the first ophthalmic surgeon for operating on cataract. [1] [2] [3] Arab scientists are some of the earliest to have written about and drawn the anatomy of the eye—the earliest known diagram being in Hunain ibn Is-hâq's Book of the Ten Treatises on the Eye. Earlier manuscripts exist which refer to diagrams which are not known to have survived. Current knowledge of the Græco-Roman understanding of the eye is limited, as many manuscripts lacked diagrams. In fact, there are very few Græco-Roman diagrams of the eye still in existence. Thus, it is not clear to which structures the texts refer, and what purpose they were thought to have.
The pre-Hippocratics largely based their anatomical conceptions of the eye on speculation, rather than empiricism. They recognised the sclera and transparent cornea running flushly as the outer coating of the eye, with an inner layer with pupil, and a fluid at the centre. It was believed, by Alcamaeon and others, that this fluid was the medium of vision and flowed from the eye to the brain via a tube. Aristotle advanced such ideas with empiricism. He dissected the eyes of animals, and discovering three layers (not two), found that the fluid was of a constant consistency with the lens forming (or congealing) after death, and the surrounding layers were seen to be juxtaposed. He, and his contemporaries, further put forth the existence of three tubes leading from the eye, not one. One tube from each eye met within the skull.
Alexandrian studies extensively contributed to knowledge of the eye. Aëtius tells us that Herophilus dedicated an entire study to the eye which no longer exists. In fact, no manuscripts from the region and time are known to have survived, leading us to rely on Celsius' account—which is seen as a confused account written by a man who did not know the subject matter. From Celsius it is known that the lens had been recognised, and they no longer saw a fluid flowing to the brain through some hollow tube, but likely a continuation of layers of tissue into the brain. Celsius failed to recognise the retina's role, and did not think it was the tissue that continued into the brain.
Rufus recognised a more modern eye, with conjunctiva, extending as a fourth epithelial layer over the eye. Rufus was the first to recognise a two chambered eye - with one chamber from cornea to lens (filled with water), the other from lens to retina (filled with an egg-white-like substance). Galen remedied some mistakes including the curvature of the cornea and lens, the nature of the optic nerve, and the existence of a posterior chamber. Though this model was roughly a correct but simplistic modern model of the eye, it contained errors. Yet it was not advanced upon again until after Vesalius. A ciliary body was then discovered and the sclera, retina, choroid and cornea were seen to meet at the same point. The two chambers were seen to hold the same fluid as well as the lens being attached to the choroid. Galen continued the notion of a central canal, though he dissected the optic nerve, and saw it was solid, He mistakenly counted seven optical muscles, one too many. He also knew of the tear ducts.
After Galen a period of speculation is again noted by Arab scientists - the lens modified Galen's model to place the lens in the middle of the eye, a notion which lasted until Versalius reversed the era of speculation. He, however, was not an ophthalmologist and taught that the eye was a more primitive notion than the notion of both Galen and the Arabian scientists - the cornea was not seen as being of greater curvature and the posterior side of the lens wasn't seen to be larger.
Understanding of the eye had been so slow to develop because for a long time the lens was perceived to be the seat of vision, not a tool of vision. This mistake was corrected when Fabricius and his successors correctly placed the lens and developed the modern notion of the structure of the eye. They removed the idea of Galen's seventh muscle (the retractor bulbi) and reinstated the correct curvatures of the lens and cornea, as well as stating the ciliary body as a connective structure between the lens and the choroid.
The seventeenth and eighteenth century saw the use of hand-lenses (by Malpighi), microscopes (van Leeuwenhoek), preparations for fixing the eye for study (Ruysch) and later the freezing of the eye (Petit). This allowed for detailed study of the eye and an advanced model. Some mistakes persisted such as: why the pupil changed size (seen to be vessels of the iris filling with blood), the existence of the posterior chamber, and of course the nature of the retina. In 1722 Leeuwenhoek noted the existence of rods and cones though they were not properly discovered until Gottfried Reinhold Treviranus in 1834 by use of a microscope.
The establishment of the first dedicated ophthalmic hospital in 1805 - now called Moorfields Eye Hospital in London, England was a transforming event in modern ophthalmology. Clinical developments at Moorfields and the founding of the Institute of Ophthalmology by Sir Stewart Duke-Elder established the site as the largest eye hospital in the world and a nexus for ophthalmic research.
[edit] Professional requirements
Ophthalmologists are medical doctors who have completed medical school and embark on a training schedule that generally lasts four years after medical school in most countries. Many ophthalmologists also undergo additional specialized training in one of the many subspecialities. Ophthalmology was the first branch of medicine to offer board certification, now a standard practice among all specialties.
In the United States, four years of training after medical school are required, with the first year being an internship in surgery, internal medicine, pediatrics, or a general transition year. The scope of a physician's licensure is such that he or she need not be board certified in ophthalmology to practice as an ophthalmologist. The American Academy of Ophthalmology (AAO) promotes the use of the phrase "Eye MD" to distinguish ophthalmologists from optometrists who hold the degree OD (Doctor of Optometry). (This, however, sometimes leads to confusion among patients, since a few ophthalmologists' primary medical degree is a D.O., or Doctor of Osteopathic Medicine, rather than an M.D. In both cases, the same residency and certification requirements must be fulfilled.) Completing the requirements of continuing medical education is mandatory for continuing licensure and re-certification. Professional bodies like AAO, ASCRS organise conferences and help members through CME programs to maintain certification, in addition to congress advocacy and peer support. Currently in the US there is an ongoing push by optometrists to increase the scope of their practice, including the use of lasers and incisional surgery. The AAO has been resisting these efforts, since although some procedures are simple perform in an office or operating room setting, the more extensive knowledge and training of an ophthalmologist may be required if a complication occurs.
In the United Kingdom, there are four Colleges that grant post graduate degree. The Royal College of Ophthalmologists grants MRCOphth and FRCOphth (postgraduate exams), Royal college of Edinburgh grants MRCSEd, Royal college of Glasgow grants FRCS and Royal college of Ireland grants FRCSI. Work experience as specialist registrar and one of these degrees is required for specialisation in eye diseases.
In Australia and New Zealand, the FRACO/FRANZCO is the equivalent postgraduate specialist qualification. They do not generally accept outsiders with equivalent qualifications and require repeat training on case by case basis, with possibility of certification for doctors with numerous international publications, desirous of joining academic institutions in Australia.
In India, after completing MBBS degree, post-graduation in Ophthalmology is required. The degrees are Doctor of Medicine (MD), Master of Surgery (MS), Diploma in Ophthalmic Medicine and Surgery (DOMS) or Diplomate of National Board (DNB). The concurrent training and work experience is in the form of a Junior Residency at a Medical College, Eye Hospital or Institution under the supervision of experienced faculty. Further work experience in form of fellowship, registrar or senior resident refines the skills of these eye surgeons. All India Ophthalmological Society (AIOS) and various state level Ophthalmological Societies (like DOS) hold regular conferences and actively promote continuing medical education.
In Pakistan, there is a residency program leading into FCPS which is composed of two parts.
In Canada, an Ophthalmology residency after medical school. A minimum of 5 years after the MD. degree although subspecialty training is undertaken by about 30% of fellows (FRCSC). There are about 30 vacancies per year for ophthalmology training in all of Canada.
Formal specialty training programs in veterinary ophthalmology now exist in some countries [4] [5] [6].
[edit] Sub-specialities
Ophthalmology includes sub-specialities which deal either with certain diseases or diseases of certain parts of the eye. Some of them are:
- Anterior segment surgery
- Cataract - not considered a subspecialty per se, since most general ophthalmologists do surgery for this.
- Cornea, ocular surface, and external disease
- Eye trauma
- Glaucoma
- Neuro-ophthalmology
- Ocular oncology
- Oculoplastics
- Ophthalmic pathology
- Pediatric ophthalmology/Strabismus (squint)
- Refractive surgery
- Retina and Vitreous (sometimes labelled as a posterior segment specialization)
- Uveitis/Immunology
[edit] Ophthalmic surgery
See eye surgery for a comprehensive list of surgeries performed by ophthalmologists.
[edit] Famous ophthalmologists
See also: Category:Ophthalmologists.
- Sir William Adams (UK) Founder of Exeter's West of England Eye Infirmary.
- Ignacio Barraquer (Spain) carried out the first intracapsular lens extraction using enzymatic zonulolysis.
- Alan C. Bird (UK) pioneer in medical retina and ophthalmic genetics in the second half of the 20th century. Based at Moorfields Eye Hospital and the Institute of Ophthalmology at University College London.
- Ramon Castroviejo (Spain) pioneer in corneal transplantation surgery.
- Marie Colinet, wife of Wilhelm Fabry, employs a magnet for removing a foreign body from the eye, 1627.
- Florent Cunier (Belgium) founded the world's first ophthalmologic journal, Annales d'Oculistique, 1838.
- Jacques Daviel (Normandy) claimed to be the 'father' of modern cataract surgery in that he performed intracapsular extraction instead of needling the cataract or pushing it back into the vitreous. It is said that he carried out the technique on 206 patients in 1752-3, out of which 182 were reported to be successful. These figures are not very credible, given the total lack of both anaesthesia and aseptic technique at that time.
- Frans Cornelis Donders (Dutch) published pioneering analyses of ocular biomechanics, intraocular pressure, glaucoma, and physiological optics. Made possible the prescribing of combinations of spherical and cylindrical lenses to treat astigmatism.
- Sir Stewart Duke-Elder (UK) Author of System of Ophthalmology, an immensely influential mid-20th century multivolume compendium of ophthalmic history, embryology, comparative ophthalmology, refraction, ocular basic sciences, medical ophthalmology and therapeutics, but avoiding discussion of surgical techniques (which he viewed as ephemera). Consultant at Moorfields Eye Hospital and founder of the Institute of Ophthalmology (now an integral part of University College London)
- Svyatoslav Fyodorov (Russia) - creator of radial keratotomy
- Jules Gonin (Switzerland)
- Albrecht von Graefe (Germany) Along with Helmholtz and Donders, one of the 'founding fathers' of ophthalmology as a specialty. A brilliant clinician and charismatic teacher who had an international influence on the development of ophthalmology. A pioneer in mapping visual field defects and diagnosis and treatment of glaucoma. Introduced a cataract extraction technique that remained the standard for over 100 years, and many other important surgical techniques such as iridectomy. Rationalised the use of many ophthalmically important drugs, including mydriatics & miotics. The founder of the one of the earliest ophthalmic societies (German Ophthalmological Society, 1857) and one of the earliest ophthalmic journals (Graefe's Archives of Ophthalmology). The most important ophthalmologist of the 19th century.
- Allvar Gullstrand (Sweden), Nobel Prize winner in 1911 for his research on the eye as a light-refracting apparatus. Described the schematic eye a mathematical model of the human eye based on his measurements known as the optical constants of the eye. His measurements are still used today.
- Hermann von Helmholtz, great German polymath, invented the ophthalmoscope (1851) and published important work on physiological optics, including colour vision (1850s).
- Fred Hollows (New Zealand/Australia) pioneered programs in Nepal, Eritrea, and Vietnam, and among Australian aborigines, including the establishment of cheap laboratory production of intraocular lenses in Nepal and Eritrea.
- Charles Kelman (United States) developed the cryo-probe used in intracapsular cataract extraction; introduced extracapsular cataract extraction and Kelman phacoemulsification.
- Ioannis Pallikaris (Greece), performed first LASIK surgery.
- P. Siva Reddy (India) holds the world record for the highest number of cataract operations by an individual doctor.
- Sir Harold Ridley (UK) may have been the first to successfully implant an artificial intraocular lens 1949, after observing that plastic fragments in the eyes of wartime pilots were well tolerated. He fought for decades against strong reactionary opinions to have the concept accepted as feasible and useful.
- Charles Schepens (Belgium), "father of modern retinal surgery", developer of the Schepens indirect binocular ophthalmoscope whilst at Moorfields Eye Hospital, founder of the Schepens Eye Research Institute, Boston, USA. This premier research institute is associated with Harvard Medical School and Massachusetts Eye & Ear Infirmary.
- Hermann Snellen (Netherlands) introduced the Snellen chart to study visual acuity.
- Carl Ferdinand Ritter von Arlt, the elder (Austrian) proved that myopia is largely due to an excessive axial length, published influential textbooks on eye disease, and ran annual eye clinics in needy areas long before the concept of volunteer eye camps became popular. His name is still attached to some disease signs, eg, von Arlt's line in trachoma. His son Ferdinand Ritter von Arlt, the younger, was also an ophthalmologist.
- Vladimir Petrovich Filatov (Ukraine) (1875-1956) His contributions to the medical world include the tube flap grafting method, corneal transplantation and preservation of grafts from cadaver eyes and tissue therapy. He founded The Filatov Institute of Eye Diseases & Tissue Therapy, Odessa, one of the leading eye care institutes in the world.
- Marshall M. Parks, "father of pediatric ophthalmology"
- Morton Goldberg a leader of American ophthalmology, made many contributions in understanding and treatment of ocular genetics, retinal diseases, and ocular trauma.[7]
- Robert Machemer (Germany, USA), "father of modern vitreoretinal surgery"[8]
- Meyer-Schwickerath (Germany) - father of Light(laser) surgery in Ophthalmology
[edit] See also
[edit] External links
- American Academy of Ophthalmology
- American Society of Cataract & Refractive Surgery
- European Society of Cataract & Refractive Surgery
- Royal College of Ophthalmologists
- American Board of Eye Surgeons
- American Board of Ophthalmology
- An On-Line Ophthalmology Journal Club (via JournalReview.org)
- Indian Journal of Ophthalmology
- All India Ophthalmological Society
- Delhi Ophthalmological Society
- The David G. Cogan Ophthalmic Pathology Collection
- Royal College of Surgeons in Edinburgh
