Ophthalmology

ophthalmologistophthalmicoculist
In North America, indigenous healers treated some eye diseases by rubbing or scraping the eyes or eyelids. The first ophthalmic surgeon in Great Britain was John Freke, appointed to the position by the Governors of St Bartholomew's Hospital in 1727. A major breakthrough came with the appointment of Baron de Wenzel (1724–90), a German who became oculist to King George III of England in 1772. His skill at removing cataract legitimized the field. The first dedicated ophthalmic hospital opened in 1805 in London; it is now called Moorfields Eye Hospital.

Tears

lacrimationteartear film
Eyelid. Professional mourning. Sadness.

Papilledema

papilloedemaP'''apilledemaSwelling of the optic disc (papilledema)
Papilledema or papilloedema is optic disc swelling that is caused by increased intracranial pressure due to any cause. The swelling is usually bilateral and can occur over a period of hours to weeks. Unilateral presentation is extremely rare.

Accommodation reflex

accommodationaccommodatingaccommodative
The accommodation reflex (or accommodation-convergence reflex) is a reflex action of the eye, in response to focusing on a near object, then looking at a distant object (and vice versa), comprising coordinated changes in vergence, lens shape (accommodation) and pupil size. It is dependent on cranial nerve II (afferent limb of reflex), superior centers (interneuron) and cranial nerve III (efferent limb of reflex). The change in the shape of the lens is controlled by the ciliary muscles inside the eye. Changes in contraction of the ciliary muscles alter the focal distance of the eye, causing nearer or future images to come into focus on the retina; this process is known as accommodation.

Esotropia

cross-eyedaccommodative esotropiacross-eye
Esotropia is a form of strabismus in which one or both eyes turns inward. The condition can be constantly present, or occur intermittently, and can give the affected individual a "cross-eyed" appearance. It is the opposite of exotropia and usually involves more severe axis deviation than esophoria. Esotropia is sometimes erroneously called "lazy eye", which describes the condition of amblyopia—a reduction in vision of one or both eyes that is not the result of any pathology of the eye and cannot be resolved by the use of corrective lenses.

Trigeminal nerve

trigeminalVfifth cranial nerve
The ophthalmic nerve (V 1 ) carries sensory information from the scalp and forehead, the upper eyelid, the conjunctiva and cornea of the eye, the nose (including the tip of the nose, except alae nasi), the nasal mucosa, the frontal sinuses and parts of the meninges (the dura and blood vessels). The maxillary nerve (V 2 ) carries sensory information from the lower eyelid and cheek, the nares and upper lip, the upper teeth and gums, the nasal mucosa, the palate and roof of the pharynx, the maxillary, ethmoid and sphenoid sinuses and parts of the meninges.

Nystagmus

nystagmus, pathologicinvoluntary eye movementsnystagmus, congenital
Nystagmus is a condition of involuntary (or voluntary, in rare cases) eye movement, acquired in infancy or later in life, that may result in reduced or limited vision. Due to the involuntary movement of the eye, it has been called "dancing eyes".

Anastomosis

anastomosesanastomosinganastomose
An anastomosis (plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be normal (such as the foramen ovale in a fetus's heart) or abnormal (such as the patent foramen ovale in an adult's heart); it may be acquired (such as an arteriovenous fistula) or innate (such as the arteriovenous shunt of a metarteriole); and it may be natural (such as the aforementioned examples) or artificial (such as a surgical anastomosis). The reestablishment of an anastomosis that had become blocked is called a reanastomosis.

Skew deviation

Skew deviation is an unusual ocular deviation (strabismus), wherein the eyes move upward (hypertropia), but in opposite directions. Skew deviation is caused by abnormal prenuclear vestibular input to the ocular motor nuclei, most commonly due to brainstem or cerebellar stroke. Other causes include multiple sclerosis and head trauma. Skew deviation is usually characterized by torticollis (head tilting) and binocular torsion. The exact pathophysiology of skew deviation remains incompletely understood. Skew deviation appears to be a perturbation of the ocular tilt reaction, which is itself probably a vestigial righting response used to keep fish and other lateral-eyed animals properly oriented.

Trochlear nerve

trochlearIVfourth
The trochlear nerve, also called the fourth cranial nerve or CN IV, is a motor nerve (a somatic efferent nerve) that innervates only a single muscle: the superior oblique muscle of the eye, which operates through the pulley-like trochlea.

Internuclear ophthalmoplegia

Internuclear ophthalmoplegia (INO) is a disorder of conjugate lateral gaze in which the affected eye shows impairment of adduction. When an attempt is made to gaze contralaterally (relative to the affected eye), the affected eye adducts minimally, if at all. The contralateral eye abducts, however with nystagmus. Additionally, the divergence of the eyes leads to horizontal diplopia. That is, if the right eye is affected the patient will "see double" when looking to the left, seeing two images side-by-side. Convergence is generally preserved.

Staphylococcus aureus

S. aureusstaph infectionmethicillin-sensitive ''Staphylococcus aureus
Staphylococcus aureus is a Gram-positive, round-shaped bacterium that is a member of the Firmicutes, and it is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive for catalase and nitrate reduction and is a facultative anaerobe that can grow without the need for oxygen. Although S. aureus usually acts as a commensal of the human microbiota it can also become an opportunistic pathogen, being a common cause of skin infections including abscesses, respiratory infections such as sinusitis, and food poisoning.

Vestibulo–ocular reflex

vestibulo-ocular reflexoculocephalic reflexoculovestibular reflex
The vestibulo-ocular reflex (VOR) is a reflex, where activation of the vestibular system causes eye movement. This reflex functions to stabilize images on the retinas (in yoked vision) during head movement by producing eye movements in the direction opposite to head movement, thus preserving the image on the center of the visual field(s). For example, when the head moves to the right, the eyes move to the left, and vice versa.

Bacteria

bacteriumbacterialeubacteria
Bacteria (common noun bacteria, singular bacterium) are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only about half of the bacterial phyla have species that can be grown in the laboratory.

Acne

acne vulgariscystic acneblemishes
Acne, also known as acne vulgaris, is a long-term skin disease that occurs when hair follicles are clogged with dead skin cells and oil from the skin. It is characterized by blackheads or whiteheads, pimples, oily skin, and possible scarring. It primarily affects areas of the skin with a relatively high number of oil glands, including the face, upper part of the chest, and back. The resulting appearance can lead to anxiety, reduced self-esteem and, in extreme cases, depression or thoughts of suicide.

Antibiotic

antibioticsantibacterialantibacterials
An antibiotic is a type of antimicrobial substance active against bacteria and is the most important type of antibacterial agent for fighting bacterial infections. Antibiotic medications are widely used in the treatment and prevention of such infections. They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the common cold or influenza; drugs which inhibit viruses are termed antiviral drugs or antivirals rather than antibiotics.

Gland

glandsglandularglandular tissue
A gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland).

Dandruff

scurfanti-dandruffantidandruff
Dandruff is a skin condition that mainly affects the scalp. Symptoms include flaking and sometimes mild itchiness. It can result in social or self-esteem problems. A more severe form of the condition, which includes inflammation of the skin, is known as seborrhoeic dermatitis.

Cerebral shunt

shuntventriculoperitoneal shuntcerebrospinal fluid shunts
Cerebral shunts are commonly used to treat hydrocephalus, the swelling of the brain due to excess buildup of cerebrospinal fluid (CSF). If left unchecked, the cerebrospinal fluid can build up leading to an increase in intracranial pressure (ICP) which can lead to intracranial hematoma, cerebral edema, crushed brain tissue or herniation. The cerebral shunt can be used to alleviate or prevent these problems in patients who suffer from hydrocephalus or other related diseases. Shunts can come in a variety of forms but most of them consist of a valve housing connected to a catheter, the end of which is usually placed in the peritoneal cavity.

Warm compress

warm compresseswarm moist compress
Non-steroidal anti-inflammatory drugs and corticosteroids may also be used in conjunction. dry eyes. pinkeye (conjunctivitis). stye or chalazion. swollen eyelids (blephartis). muscle spasms or pain.

Demodex

Demodex canisD. canisDemodex erminae
Blepharitis (inflammation of the eyelids) can be also caused by Demodex mites. Research about human infection by Demodex mites is ongoing: The natural host of Demodex canis is the domestic dog. Although it can temporarily infect humans, D. canis mites cannot survive on the human skin and therefore will die shortly after exposure and are considered not to be zoonotic. Naturally, the D. canis mite has a commensal relationship with the dog and therefore under normal conditions does not produce any clinical signs or disease. The escalation of a commensal D. canis infestation into one requiring clinical attention usually involves complex immune factors.

Hair follicle

hair folliclesfolliclefollicles
The hair follicle is a dynamic organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction between hormones, neuropeptides and immune cells. This complex interaction induces the hair follicle to produce different types of hair as seen on different parts of the body. For example, terminal hairs grow on the scalp and lanugo hairs are seen covering the bodies of fetuses in the uterus and in some new born babies. The process of hair growth occurs in distinct sequential stages.

Midbrain

mesencephalonmid-brainmesencephalic
The nuclei of two pairs of cranial nerves are similarly located at the ventral side of the periaqueductal grey – the pair of oculomotor nuclei (which control the eyelid, and most eye movements) is located at the level of the superior colliculus, while the pair of trochlear nuclei (which helps focus vision on more proximal objects) is located caudally to that, at the level of the inferior colliculus, immediatetly lateral to the dorsal raphe nucleus.

Demodicosis

demodectic mangedemodecticDemodex Mange
Demodicosis is accompanied by itching, swelling and erythema of the eyelid margins, and the appearance of scales at the base of the eyelashes. Typically, patients complain of eyestrain. Demodectic mange also occurs in other domestic and wild animals including captive pandas and in China. The mites are specific to their hosts, and each mammal species is host to one or two unique species of Demodex mites. There are two types of demodectic mange in cats. Demodex cati causes follicular mange, similar to that seen in dogs, though it is much less common. Demodex gatoi is a more superficial form of mange, causes an itchy skin condition, and is contagious amongst cats.

Superior colliculus

optic tectumsuperior colliculicolliculi
The superior colliculus (Latin, upper hill) is a paired structure of the mammalian midbrain. In other vertebrates the homologous structure is known as the optic tectum or simply tectum. The adjective form tectal is commonly used for mammals as well as other vertebrates.