Eyelash

Structure and function of the hair follicle

The main functions of mammalian hair are insulation and camouflage. These are no longer necessary for the naked ape, although vestiges of this remain in the seasonal patterns of our hair growth (Randall and Ebling 1991) and the erection of our body hairs when shivering with cold. Mammals often have specialised hairs as neuroreceptors e.g. whiskers and this remains slightly in human body hair with its good nerve supply. However, the main functions of human hair are protection and communication. Eyelashes and eyebrow hairs prevent substances entering the eyes and scalp hair may protect the scalp and back of the neck from sun damage during our upright posture. During puberty the development of axillary and pubic hair signals the beginning of sexual maturity in both sexes (Marshall and Tanner 1969 1970 Winter and Faiman 1972 1973) while the male beard, like the mane of the lion, readily distinguishes the sexes.

Diseases of the Eyelid

Entropion is a turning in of the eyelid margin so that there is a rubbing of eyelashes or cilia, with resultant ocular irritation. An ectropion is a turning out of the eyelid margin so that the eye builds up excessive tears and becomes inflamed. Both conditions are more common in the older adult population. Entropion and ectropion can cause symptoms of irritation and corneal changes.

Epilogue on zebras and quaggas

'I stayed on a farm once, where there was quaggas,' he announced, 'And of coursc I knows a quagga when I sees one. A quagga is like a big buck, with stripes all over his backside, like he got lashes. That's a quagga. You can't fool me, you can't. You got to go and learn, that's what. You got no brains, that's thai.'

Clinical Manifestations and Pathology Trachoma

Stage 4 (healed trachoma) is the final stage of the disease in which healing has been completed without any signs of inflammation, and the disease is no longer infectious. Trachomatous scarring remains, however, and may deform the upper lid and cause opaqueness in the cornea. The thickening of the upper lids gives a hooded appearance to the eyes. Because scarring of the upper lids involves the tarsal plate, which buckles, twists, and inturns, these features indicate a past trachoma. When the inturning occurs, the lashes often rub on the cornea (trichiasis), causing constant irritation and tearing until the corneal surface is scarred. Ulcers may develop, and bacterial infection of the ulcers can lead to blindness. Another complication may be drying of the conjunctiva and cornea. The combination of corneal scarring, opacification, and vascularization plus secondary bacterial infections all account for impaired vision and blindness (Thygeson 1964 Yanoff and Fine 1975 Grayson 1979 and...

History and Geography Antiquity

It was known in China in the twenty-seventh century B.C. (Bietti and Werner 1967) and ancient Egypt from the sixteenth century B.C. In 1872 George Ebers discovered a medical papyrus at Thebes that clearly described a chronic conjunctivitis (ophthalmia, lippitudo, chronic granular disease). The ancient Egyptians called the disease Hetae, and their symbol for it was the rain from heaven, which means a flowing downward of fluid. The papyrus also describes the white spot (sehet) or leukoma of the cornea, but still more clearly the hairs in the eye (shene m mert) or trichiasis (inward-growing eyelashes). All of this is very suggestive of trachoma (Worms and Marmoiton 1929 Hirschberg 1982 Meyerhof 1984). The fourth kind of trachoma is more grave than the three other kinds and exhibits still more roughness it is more dangerous and chronic. It is associated with severe pain and callosity, and it is impossible to root it out in a short space of time, on account...

PAdrenergic Antagonists

The ocular hypotensive lipids are well tolerated and rarely cause systemic side effects (headache has been reported). Local effects include conjunctival hyperemia, stinging on instillation, increase in iris pigmentation, hypertrichosis, and darkening of the eyelashes. Increases in iris pigmentation occur most commonly in patients with multicolored irides on long-term prostaglandin analog therapy. The mechanism of this effect is by its action on melanocytes of the iris, in which the irides become darker because of increased production of melanin in the iris.41,42 The 12-month incidence of iris pigmentation varies among the agents. Latanoprost appears to have the highest incidence of iris pigmentation after 12 months of therapy (5.2-25 ) compared to travoprost (3.1 ) and bimatoprost (1-5.5 ).43-48 The increase in pigmentation may be irreversible or may reverse at a very slow rate. Increased iris pigmentation appears to be only a cosmetic effect but may affect your product selection...

The paradoxical effects of androgens on human hair growth

Vellus Hair

In utero the humanbodyiscoveredwith quite long, colourless lanugo hairs. These are shed before birth and at birth, or shortly after, babies normally exhibit pigmented, quite thick protective hairs on the eyebrows and eyelashes and variable amounts on the scalp by the age of three or four the scalp hair is usually quite well developed, though it will not yet have reached its maximum length. These readily visible pigmented hairs are known as terminal hairs and are formed by large deep terminal follicles (Fig. 6.2). This emphasises that terminal hair growth on the scalp, eyelashes and eyebrows is not androgen-dependent. The rest of the body is often considered hairless but, except for the glabrous skin of the lips, palms and sole of the feet, is normally covered with fine, short almost colourless vellus hairs produced by small short vellus follicles (Fig. 6.2). The molecular mechanisms involved in the distribution and formation of the different types of follicles during embryogenesis are...

Basilar Skull Fracture Raccoon Eyes

Raccoon Eyes Medical

A stye, or acute hordeolum, is a localized abscess in an eyelash follicle and is caused by a staphylococcal infection. It is a painful, red infection that looks like a pimple pointing on the lid margin. Figure 10-30 depicts a stye. Blepharitis is a chronic inflammation of the eyelid margins. The most common form is associated with small white scales around the lid margin and the eyelashes, which stick together and may fall out. There are several annoying symptoms itching, tearing, and redness. The condition is frequently associated with seborrhe-ic dermatitis. Figure 10-31 shows blepharitis. The tarsal conjunctiva may be seen by everting the eyelid. Ask the patient to keep the eyes open and look downward. Grasp gently some of the eyelashes of the upper lid. Pull the eyelid away from the globe, and press the tip of an applicator stick against the upper border of the tarsal plate. Then quickly turn the tarsal plate over the applicator stick, using it as a fulcrum. Your thumb can now be...

Signs of anaesthesia Fig 372

This is seen with inhalation induction, but is passed rapidly during i.v. induction. Respiration is erratic, breath-holding may occur, laryngeal and pharyngeal reflexes are active and stimulation of pharynx or larynx, e.g. by insertion of a Guedel or laryngeal mask airway, can produce laryngeal spasm. The eyelash reflex (used as a sign of unconsciousness with i.v. induction) is abolished in stage 2, but the eyelid reflex (resistance to elevation of eyelid) remains present.

Dosage and administration

The dose required to produce anaesthesia varies, and the response of each patient must be assessed carefully cardiovascular depression is exaggerated if excessive doses are given. In healthy adults, an initial dose of 4 mg kg1 should be administered over 15-20 s if loss of the eyelash reflex does not occur within 30 s, supplementary doses of 50-100 mg should be given slowly until consciousness is lost. In young children, a dose of 6 mg kg-1 is usually necessary. Elderly patients often require smaller doses (e.g. 2.5-3 mg kg-1) than young adults.

Central nervous system

Anaesthesia is induced within 20-40 s after i.v. administration in otherwise healthy young adults. Transfer from blood to the sites of action in the brain is slower than with thiopental, and there is a delay in disappearance of the eyelash reflex, normally used as a sign of unconsciousness after administration of barbiturate anaesthetic agents. Overdosage of propofol, with exaggerated side-effects, may result if this clinical sign is used loss of verbal contact is a better end-point. EEG frequency decreases, and amplitude increases. Propofol reduces the duration of seizures induced by ECT in humans. However, there have been reports of convulsions following the use of propofol and it is recommended that caution be exercised in administration of propofol to epileptic patients. Normally cerebral metabolic rate, CBF and intracranial pressure are reduced.

Structure and Physiology

The eyelids and eyelashes protect the eyes. The eyelids cover the globe and lubricate its surface. The meibomian glands, which are modified sebaceous glands in the eyelids, secrete an oily lubricating substance to retard evaporation. The openings of these glands are at the lid margins. Meibomian glands Eyelashes Pupil Cornea Anterior chamber Posterior chamber

Trachoma Clinical Summary

Although symptoms occur along a continuum, there are two distinct phases, the active phase and the scarring (cicatricial) phase. The active phase presents with mild itching, irritation, and discharge from the eye associated with inflammation of the conjunctivae, particularly the superior tarsal plate. With progression, symptoms include marked photophobia, blurred vision, and eye pain. The cicatricial phase occurs after repeated or severe infection with chronic inflammation causing the upper lid to shorten (entropion) with subsequent inversion of the eyelashes (trichiasis). Trichiasis causes painful corneal abrasions which over time leads to corneal edema, ulceration, scarring, opacities, and ultimately blindness. The lacrimal glands may be affected leading to dryness and increased eye irritation. Trachoma usually affects both eyes. Trachoma is a clinical diagnosis but may be confirmed by culture. Community-based efforts on education of hygiene and behavior modification can decrease...

Emergency Department Treatment And Disposition

Lindane shampoo should be lathered into the pubic, perineal, and perianal hair or lindane lotion applied in the affected areas and left on for 10 minutes and rinsed off. Synergized pyrethrins (RID), or synthetic pyrethrins, may also be used. Since lindane may be toxic, pyrethrins are preferred in pregnant women and children. Treatment should be repeated in 1 week to treat any nits that may have hatched. Clothing worn or linen used in the preceding 24 hours should be washed. Mechanical removal of nits attached to hairs should be attempted. Petroleum jelly or any bland ophthalmic ointment can be applied to the eyelashes twice daily for a week to treat infestation of the eyelashes. Sexual contacts should be examined. Figure 9.30.

Ocular Foreign Body and Other Eye Injuries

Corneal abrasions are often caused by foreign bodies underneath the upper lid or inadvertent injury from a finger or small object. Evert the lid and examine for conjunctival foreign bodies. To evert the lid, the patient is seated and asked to look downward. The upper lid is grasped by its central lashes and pulled downward and slightly outward. The examiner then depresses the upper lid with a cotton applicator proximal to the upper tarsus margin. Gentle pressure is maintained until the upper lid is flipped into the everted position. Frequently, the foreign body is observed and can be removed with a cotton applicator or forceps. Corneal abrasions generally can be treated with an antibiotic ointment. Small abrasions often do not require patching. Large corneal abrasions may require pressure patching or bandage contact lens.

Blepharitis

Blepharitis is a chronic lid inflammation that involves abnormalities of the glands surrounding the eyelashes. The two most common types are chronic staphylococcal infections of the lid and seborrheic blepharitis (Fig. 41-6). Staphylococcal blepharitis is the most common inflammation of the external eye. It is frequently asymptomatic initially, but as the disease progresses, the patient complains of foreign body sensation, matting of the lashes, and burning. Lid crusting, discharge, redness, and loss of lashes are observed. Seborrheic blepharitis is associated with seborrhea of the scalp, lashes, eyebrows, and ears, characterized by greasy, dandruff-like scales on the lashes. Blepharitis is not associated with skin ulcerations.

Randall

Androgens are the most obvious regulators of human hair growth. Although hair with a major protective role, such as the eyelashes, eyebrows and scalp hair, is produced by children in the absence of androgens, the formation of long pigmented hair on the axillae, pubis, face etc. needs androgens in both sexes. In contrast, androgens may also inhibit hair growth on the scalp, causing baldness. How one type of hormone can simultaneously cause these contradictory effects in the same tissue in different body sites within one person is an endocrinological paradox. The hair follicle has another exciting characteristic. It is the only tissue in the adult body which can regenerate, often producing a new hair with different features. This is how androgens can stimulate such major changes.

Trachoma

Stage 4 (healed trachoma) is the final stage in which healing has been completed without inflammation, and the disease is no longer infectious. Trachomatous scarring remains, however, and may deform the upper lid and cause opaqueness in the cornea. When the eyelid in-turns, the lashes rub on the cornea (trichiasis), irritating, tearing, and scarring the corneal surface. Ulcers may develop, and bacterial infection of the ulcers can lead to blindness. Another complication may be drying of the conjunctiva and cornea. Many combinations of complications may account for impaired vision and blindness.

VIII80 Leprosy

The early and more subtle physiological changes caused by leprosy have been noted consistently only since the nineteenth century. Owing to the involvement of nerves supplying the dermis, the heavily innervated face loses free play of expression and affect. Eyelashes and the lateral part of the eyebrows disappear long before other, grosser signs betray infection.

Ocular Medications

A newer class of glaucoma medications includes the pros-taglandins and prostamides. These medications, such as latanoprost (Xalatan), travoprost (Travatan), and unoprostone isopropyl (Rescula), are associated with increased eyelash growth and increased pigmentation of the iris, conjunctiva, and eyelids. Additionally, these medications can induce conjunctival hyperemia and can increase the risk of postoperative retinal edema.