Ophthalmology (, ). is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders. Ophthalmologists also diagnose systemic (other parts of the body) diseases using changes seen in the eyes.
An ophthalmologist is a physician with an MD or DO degree who undergoes specialty training in medical and surgical eye care. In the United States, following graduation from medical school, one must complete a four-year residency in ophthalmology to become an ophthalmologist. Following residency, additional sub-specialty training (or fellowship) may be sought in a particular aspect of eye diseases.
Ophthalmologists prescribe medications to treat eye diseases, implement laser therapy, and perform surgery when needed. Ophthalmologists provide both primary and specialty eye care—medical and surgical. Most ophthalmologists participate in academic research on eye diseases at some point in their training, and many include research as part of their career. Ophthalmology has always been at the forefront of medical research with a long history of advancement and innovation in eye care.
A former term for this medical branch is oculism.
Diseases A brief list of some of the most common diseases treated by ophthalmologists: Cataract Excessive tearing (tear duct obstruction and others) Proptosis (bulging eyes) Graves' ophthalmopathy Eye, lid and orbit tumors Ptosis (drooping eyelid) Diabetic retinopathy Dry eye syndrome Glaucoma Macular degeneration Retinal detachment Endophthalmitis (infection in the eye) Refractive errors (glasses, contact lenses, surgery including LASIK) Strabismus (misalignment or deviation of eyes) Uveitis (Eye inflammation) Eye injury Globe rupture Orbital fracture
Diagnosis
Eye examination The following are steps often performed during a complete eye examination that enable diagnosis: Visual acuity assessment Ocular tonometry to determine intraocular pressure Extraocular motility and ocular alignment assessment Slit lamp examination Dilated fundus examination Gonioscopy Refraction
Specialized tests Optical coherence tomography (OCT) is a medical technological platform used to assess ocular structures. Physicians then use the information to assess the staging of pathological processes and confirm clinical diagnoses. Subsequent OCT scans are used to assess the efficacy of managing diabetic retinopathy, age-related macular degeneration, and glaucoma.
Optical coherence tomography angiography (OCTA) and fluorescein angiography to visualize the vascular networks of the retina and choroid.
Electroretinography (ERG) measures the electrical responses of various cell types in the retina, including the photoreceptors (rods and cones), inner retinal cells (bipolar and amacrine cells), and the ganglion cells.
Electrooculography (EOG) is a technique for measuring the corneo-retinal standing potential that exists between the front and the back of the human eye. The resulting signal is called the electrooculogram. Primary applications are in ophthalmological diagnosis and in recording eye movements.
Visual field testing to detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma, stroke, pituitary disease, brain tumours or other neurological deficits.
Corneal topography is a non-invasive medical imaging technique for mapping the anterior curvature of the cornea, the outer structure of the eye.
Ultrasonography of the eyes may be performed by an ophthalmologist.
Ophthalmic surgery
Eye surgery, also known as ocular surgery, is surgery performed on the eye or its adnexa by an ophthalmologist. The eye is a fragile organ and requires extreme care before, during, and after a surgical procedure. An eye surgeon is responsible for selecting the appropriate surgical procedure for the patient and for taking the necessary safety precautions.
Subspecialties Ophthalmology includes subspecialities that deal either with certain diseases or diseases of certain parts of the eye. Some of them are: Anterior segment surgery Cornea, ocular surface, and external disease Glaucoma Neuro-ophthalmology Ocular oncology Oculoplastics and orbit surgery Ophthalmic pathology Pediatric ophthalmology/strabismus (misalignment of the eyes) Refractive surgery Medical retina, deals with treatment of retinal problems through non-surgical means Uveitis Veterinary specialty training programs in veterinary ophthalmology exist in some countries. Vitreo-retinal surgery, deals with surgical management of retinal and posterior segment diseases
Medical retina and vitreo-retinal surgery are sometimes combined, and together they are called posterior segment subspecialization.
Etymology The Greek roots of the word ophthalmology are ὀφθαλμός (, "eye") and -λoγία (-, "study, discourse"), i.e., "the study of eyes". The discipline applies to all animal eyes, whether human or not, since the practice and procedures are quite similar with respect to disease processes, although there are differences in the anatomy or disease prevalence.
History
Ancient near east and the Greek period In the Ebers Papyrus from ancient Egypt dating to 1550 BC, a section is devoted to eye diseases.
Prior to Hippocrates, physicians largely based their anatomical conceptions of the eye on speculation, rather than empiricism. They recognized 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 (fifth century BC) and others, that this fluid was the medium of vision and flowed from the eye to the brain by 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.
The Greek physician Rufus of Ephesus (first century AD) recognized a more modern concept of the 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 a substance resembling egg whites).
Celsus the Greek philosopher of the second century AD gave a detailed description of cataract surgery by the couching method.
The Greek physician Galen (second century AD) remedied some mistaken descriptions, including about the curvature of the cornea and lens, the nature of the optic nerve, and the existence of a posterior chamber. Although this model was a roughly correct modern model of the eye, it contained errors. Still, 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, but he dissected the optic nerve and saw that it was solid. He mistakenly counted seven optical muscles, one too many. He also knew of the tear ducts.
Ancient India The Sushruta Samhita is an ancient Sanskrit text attributed to the Indian surgeon Sushruta. The final volume of the Sushruta Samhita, known as the Uttaratantra, contains the ophthalmic sections of the work, including the method of cataract surgery, and is attributed in the traditions of both India and China to a figure named Nagarjuna, who lived in the early Common Era.
The Uttaratantra describes 76 ocular diseases (of these, 51 surgical) as well as several ophthalmological surgical instruments and techniques.Bidyadhar, N.K. (1939), Sushruta's Ophthalmic Operations, Archives of Ophthalmology, 22, page 553.Agarwal, R.K. (1965), Ancient Indian Ophthalmology, The Ophthalmic Optician, 5(21),1093–1100 (the title of this journal was changed to Optometry Today in 1985), published by the Association of Optometrists, London, England. His description of cataract surgery was compatible with the method of couching.
Medieval Islam
Medieval Islamic Arabic and Persian scientists (unlike their classical predecessors) considered it normal to combine theory and practice, including the crafting of precise instruments, and therefore found it natural to combine the study of the eye with the practical application of that knowledge. Hunayn ibn Ishaq (a Christian), and others beginning with the medieval Arabic period, taught that the crystalline lens is in the exact center of the eye. This idea was propagated until the end of the 1500s.
Ibn al-Nafis, an Arabic native of Damascus, wrote a large textbook, The Polished Book on Experimental Ophthalmology, divided into two parts, On the Theory of Ophthalmology and Simple and Compounded Ophthalmic Drugs.
Avicenna wrote in his Canon "rescheth", which means "retiformis", and Gerard of Cremona translated this at approximately 1150 into the new term "retina".
Early Modern period In the early modern period, medicine increasingly shifted toward specialization. This was a result of building on developments that had begun in the Middle Ages. This shift further emphasized organs and diseases as separate from each other, rather than viewing the body as a whole. Ophthalmology, the medical branch concerning the eye, emerged more clearly as one of these early specialities; specialists were referred to as "oculists." Oculists were often not university-trained physicians, and instead relied on practical and surgical experience. Tensions formed between theory-based learned physicians and hands-on practitioners.
The early modern period included a few key figures. Georg Bartisch (c. 1535-1607) was a German oculist who wrote Ophthalmodouleia, das ist Augendienst (1583). This text contributed greatly to the knowledge of eye diseases and surgery in the sixteenth century. Bartisch became a surgical practitioner despite little formal university education. His work is known for its detailed descriptions of ocular conditions, surgical techniques, and its collection of visual illustrations. Bartisch believed in direct observation and practical experience as a method of teaching.
Another historical figure was the French surgeon Jacques Guillemeau (c. 1550-1613) author of A Worthy Treatise of the Eyes (1587). This text was among the earliest works entirely devoted to ocular diseases, and it is known for its inclusion of the detailed anatomy of the eye and systematic classification of eye diseases. By combining classical authorities and his personal surgical experience, a shift towards observation and empirical practice was shown. Another important figure was Richard Banister (c. 1570-1626), an English oculist and writer known for his detailed descriptions of eye diseases and his emphasis on careful observation of patients. He discussed visual disorders and treatments, and contributed practical surgical knowledge to the field. He represented a shift toward more systematic clinical understanding.
Surgical practices underwent great transformations during this period, although some techniques had been discovered much earlier. One such method was couching, which remained the primary treatment for cataracts throughout the early modern period. In the procedure. a needle was used to displace the opaque cataract lens. This practice did not remove the cataract, but it displaced the obstruction, allowing light to enter the eye. Though often temporary and risky, the practice restored partial vision; this made it appealing to the blind. Despite the continued use of such procedures and a surge in willingness to surgically intervene, surgery remained imprecise.