They do this by restricting the blood flow leaving the head, thereby increasing blood pressure and rupturing tiny vessels around the eyelids. The blood not only confuses predators, but also tastes foul to canine and feline predators. It appears to have no effect against predatory birds. Only three closely related species (P. mcallii, P. modestum, and P. platyrhinos) are certainly known to be unable to squirt blood. While previous thought held that compounds were added to the blood from glands in the ocular sinus cavity, current research has shown that the chemical compounds that make up the defense are already in the circulating blood.
horned toadhorny toadsphrynosomatid
The skin is tubercular on the dorsal surface, prominently on the eyelids and around the tympanum. Fingers are half webbed and toes are fully webbed, both having well-developed discs. The tympanum is small and indistinct, and a vocal sac is not present. Males have black, spiny nuptial pads on their thumbs and "accessory spines" on their chests. These spines are used in amplexus by the males to attain a better grip on the females.
punctapuncta lacrimalialacrimal puncta
The lacrimal punctum (plural puncta) or lacrimal point, is a minute opening on the summits of the lacrimal papillae, seen on the margins of the eyelids at the lateral extremity of the lacrimal lake. There are two lacrimal puncta in the medial (inside) portion of each eyelid. Together, they function to collect tears produced by the lacrimal glands. The fluid is conveyed through the lacrimal canaliculi to the lacrimal sac, and thence via the nasolacrimal duct to the inferior nasal meatus of the nasal passage. * Diagram and discussion at aafp.org Imperforate lacrimal punctum. Lacrimal apparatus. Punctal plug.
Unlike most geckos, all species in the genus possess movable eyelids, and cannot climb up smooth surfaces, considering they do not have toe pads like most geckos. It has become a well-established pet in many places. Common leopard geckos were first described as a species by zoologist Edward Blyth in 1854 as Eublepharis macularius. The generic name Eublepharis is a combination of the Greek words eu (good) and blepharos (eyelid), as having eyelids is the primary characteristic that distinguishes members of this subfamily from other geckos, along with a lack of lamellae, bumpy skin, and crepuscular behavior, though they may be found awake during the day occasionally.
superior tarsalMüller muscleMüller's muscle
The superior tarsal muscle works to keep the upper eyelid raised after the levator palpebrae superioris has raised the upper eyelid. Damage to some elements of the sympathetic nervous system can inhibit this muscle, causing a drooping eyelid (partial ptosis). This is seen in Horner's syndrome. The ptosis seen in Horner's syndrome is of a lesser degree than is seen with an oculomotor nerve palsy. The muscle derives its name, typically used for drying. The term Müller's muscle is sometimes used as a synonym. However, the same term is also used for the circular fibres of the ciliary muscle, and also for the orbitalis muscle that covers the inferior orbital fissure.
A symblepharon is a partial or complete adhesion of the palpebral conjunctiva of the eyelid to the bulbar conjunctiva of the eyeball. It results either from disease (conjunctival sequelae of trachoma) or trauma. Cicatricial pemphigoid and, in severe cases, rosacea may cause symblepharon. It is rarely congenital. and its treatment is symblepharectomy.
Lid lag is the static situation in which the upper eyelid is higher than normal with the globe in downgaze. It is most often a sign of thyroid eye disease, but may also occur with cicatricial changes to the eyelid or congenital ptosis. Lid lag differs from Von Graefe's sign in that the latter is a dynamic process. It can also be the manifestation of chemosis (swelling (or edema) of the conjunctiva)
goblet cellsglandular epithelial cellsgoblet
They are found inside the trachea, bronchi, and larger bronchioles in the respiratory tract, small intestines, the large intestine, and conjunctiva in the upper eyelid. In the conjunctiva goblet cells are a source of mucin in tears and they also secrete different types of mucins onto the ocular surface. In the lacrimal glands, mucus is synthesized by acinar cells instead. Goblet cells are simple columnar epithelial cells, having a height of four times that of their width.
Permanent makeup is a cosmetic technique which employs tattoos (permanent pigmentation of the dermis) as a means of producing designs that resemble makeup, such as eyelining and other permanent enhancing colors to the skin of the face, lips, and eyelids. It is also used to produce artificial eyebrows, particularly in people who have lost them as a consequence of old age, disease, such as alopecia totalis, chemotherapy, or a genetic disturbance, and to disguise scars and white spots in the skin such as in vitiligo. It is also used to restore or enhance the breast's areola, such as after breast surgery.
skin tagsacrochordonFibroepithelial polyp
They may also occur on the face, usually on the eyelids. Perianal skin tags can be associated with Crohn's disease. Acrochorda are generally harmless and painless and usually do not grow or change over time. Though tags up to a half-inch long have been seen, they are typically the size of a grain of rice. The surface of an acrochordon may be smooth or irregular in appearance and is often raised from the surface of the skin on a fleshy stalk called a peduncle. Microscopically, an acrochordon consists of a fibrovascular core, sometimes also with fat cells, covered by an unremarkable epidermis. However, tags may become irritated by shaving, clothing, jewellery or eczema.
Krause's glands are small, mucous accessory lacrimal glands that are found underneath the eyelid where the upper and lower conjuctivae meet. Their ducts unite into a rather long sinus which open into the fornix conjunctiva. There are approximately forty Krause glands in the region of the upper eyelid, and around 6 to 8 in the region of the lower lid. The function of these glands are to produce tears which are secreted onto the surface of the conjuctiva. There are rare instances of tumors associated with Krause's glands. They usually occur as retention cysts in cicatricial conditions of the conjunctiva.
oculoplasticoculoplastic surgeryophthalmic plastic and orbital surgery
A canthorrhaphy is suturing of the outer canthus to shorten the palpebral fissure. A canthotomy is the surgical division of the canthus, usually the outer canthus. A lateral canthotomy is the surgical division of the outer canthus. Epicanthoplasty. Tarsorrhaphy is a procedure in which the eyelids are partially sewn together to narrow the opening (i.e. palpebral fissure). Removal of eyelid tumors (such as basal cell carcinoma or squamous cell carcinoma). A Hughes procedure. External or Endoscopic Dacryocystorhinostomy (DCR) for nasolacrimal duct obstruction. Canalicular trauma (canalicular laceration) repair.
Blepharophyma is chronic swelling of eyelids, mainly due to sebaceous gland hyperplasia. List of cutaneous conditions. Phymas in rosacea.
The syndrome consists of severe micrognathia, cleft lip and/or palate, hypoplasia or aplasia of the postaxial elements of the limbs, coloboma of the eyelids, and supernumerary nipples. Additional features of the syndrome include downward-slanting palpebral fissures, malar hypoplasia, malformed ears, and a broad nasal ridge.
lacrimal glandslacrimaltear glands
The smaller palpebral portion lies close to the eye, along the inner surface of the eyelid; if the upper eyelid is everted, the palpebral portion can be seen. The orbital portion contains fine interlobular ducts that unite to form 3–5 main secretory ducts, joining 5–7 ducts in the palpebral portion before the secreted fluid may enter on the surface of the eye. Tears secreted collect in the fornix conjunctiva of the upper lid, and pass over the eye surface to the lacrimal puncta, small holes found at the inner corner of the eyelids. These pass the tears through the lacrimal canaliculi on to the lacrimal sac, in turn to the nasolacrimal duct, which dumps them out into the nose.
cornealcorneal diseasecorneal diseases
The cornea has unmyelinated nerve endings sensitive to touch, temperature and chemicals; a touch of the cornea causes an involuntary reflex to close the eyelid. Because transparency is of prime importance, the healthy cornea does not have or need blood vessels within it. Instead, oxygen dissolves in tears and then diffuses throughout the cornea to keep it healthy. Similarly, nutrients are transported via diffusion from the tear fluid through the outside surface and the aqueous humour through the inside surface, and also from neurotrophins supplied by nerve fibres that innervate it.
opticiansdispensing opticianoptical engineer
Opticians, like ophthalmologists and optometrists, also use a slit-lamp/bio-microscope to examine the anterior segment, or frontal structures and posterior segment, of the human eye, which includes the eyelid, sclera, conjunctiva, iris, natural crystalline lens, and cornea. The binocular slit-lamp examination provides stereoscopic magnified view of the eye structures in detail, enabling anatomical diagnoses to be made for a variety of eye conditions. While a patient is seated in the examination chair, he rests his chin and forehead on a support to steady the head. Using the biomicroscope, the optician then proceeds to examine the patient's eye.
Common presenting signs include: a protruding eye (proptosis), eyelid edema (swelling), eye pain, vision loss, inability to move the eye completely (ophthalmoplegia), and fever. It is important to correlate physical findings with patient history and reported symptoms. CT scan and MRI of the orbits are two imaging modalities that are commonly used to aid in the diagnosis and monitoring of orbital cellulitis, as they can provide detailed images that can show the extent of inflammation along with possible abscess location, size, and involvement of surrounding structures.
supranuclear palsysupranuclear palsy, progressiveParkinson's disease with hyperextension
Some of the other signs are poor eyelid function, contracture of the facial muscles, a backward tilt of the head with stiffening of the neck muscles, sleep disruption, urinary incontinence and constipation. The visual symptoms are of particular importance in the diagnosis of this disorder. Patients typically complain of difficulty reading due to the inability to look down well. Notably, the ophthalmoparesis experienced by these patients mainly concerns voluntary eye movement and the inability to make vertical saccades, which is often worse with downward saccades. Patients tend to have difficulty looking down (a downgaze palsy) followed by the addition of an upgaze palsy.
The rash often affects the face, eyelids, and hands, and sometimes the skin above joints, including the knuckles, knees, elbows, etc. The color of the rash is a pinkish purple, and is called heliotrope (after a flower of the same name with approximately this color). On the hands and face, the rash very closely resembles allergies, eczema, fifth disease, or other more common skin condition, but the heliotrope color is unique to the inflammatory process of JDMS. Some children develop calcinosis, which are calcium deposits under the skin. The rash is the source of the "dermato-" part of the name of the disease.
harlequin ichthyosisharlequin type ichthyosisharlequinism
They affect the shape of the eyelids, nose, mouth, and ears, and limit movement of the arms and legs. Restricted movement of the chest can lead to breathing difficulties. These plates fall off over several weeks. Other complications can include premature birth, infection, problems with body temperature, and dehydration. Harlequin-type ichthyosis is due to mutations of the ABCA12 genes. It is inherited from a person's parents in an autosomal recessive manner. Diagnosis is often based on appearance at birth and confirmed by genetic testing. Before birth amniocentesis or ultrasound may support the diagnosis. There is no cure. Early in life constant supportive care is typically required.