The use of cold or freezing in treatment. (See also cryosurgery.)
Astigmatism (See ASTIGMATISM.)
Blepharitis A chronic in?ammation of the lid margins. SEBORRHOEA and staphylococcal infection are likely contributors. The eyes are typically intermittently red, sore and gritty over months or years. Treatment is di?cult and may fail. Measures to reduce debris on the lid margins, intermittent courses of topical antibiotics, steroids or systemic antibiotics may help the sufferer.
Blepharospasm Involuntary closure of the eye. This may accompany irritation but may also occur without an apparent cause. It may be severe enough to interfere with vision. Treatment involves removing the source of irritation, if present. Severe and persistent cases may respond to injection of Botulinum toxin into the orbicularis muscle.
Cataract A term used to describe any opacity in the lens of the eye, from the smallest spot to total opaqueness. The prevalence of cataracts is age-related: 65 per cent of individuals in their sixth decade have some degree of lens opacity, while all those over 80 are affected. Cataracts are the most important cause of blindness worldwide. Symptoms will depend on whether one or both eyes are affected, as well as the position and density of the cataract(s). If only one eye is developing a cataract, it may be some time before the person notices it, though reading may be affected. Some people with cataracts become shortsighted, which in older people may paradoxically ‘improve’ their ability to read. Bright light may worsen vision in those with cataracts.
The extent of visual impairment depends on the nature of the cataracts, and the ?rst symptoms noticed by patients include di?culty in recognising faces and in reading, while problems watching television or driving, especially at night, are pointers to the condition. Cataracts are common but are not the only cause of deteriorating vision. Patients with cataracts should be able to point to the position of a light and their pupillary reactions should be normal. If a bright light is shone on the eye, the lens may appear brown or, in advanced cataracts, white (see diagram).
While increasing age is the commonest cause of cataract in the UK, patients with DIABETES MELLITUS, UVEITIS and a history of injury to the eye can also develop the disorder. Prolonged STEROID treatment can result in cataracts. Children may develop cataracts, and in them the condition is much more serious as vision may be irreversibly impaired because development of the brain’s ability to interpret visual signals is hindered. This may happen even if the cataracts are removed, so early referral for treatment is essential. One of the physical signs which doctors look for when they suspect cataract in adults as well as in children is the ‘red re?ex’. This is observable when an ophthalmoscopic examination of the eye is made (see OPHTHALMOSCOPE). Identi?cation of this red re?ex (a re?ection of light from the red surface of the retina –see EYE) is a key diagnostic sign in children, especially young ones.
There is no e?ective medical treatment for established cataracts. Surgery is necessary and the decision when to operate depends mainly on how the cataract(s) affect(s) the patient’s vision. Nowadays, surgery can be done at any time with limited risk. Most patients with a vision of 6/18 – 6/10 is the minimum standard for driving – or worse in both eyes should
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bene?t from surgery, though elderly people may tolerate visual acuity of 6/18 or worse, so surgery must be tailored to the individual’s needs. Younger people with a cataract will have more demanding visual requirements and so may opt for an ‘earlier’ operation. Most cataract surgery in Britain is now done under local anaesthetic and uses the ‘phaco-emulsi?cation’ method. A small hole is made in the anterior capsule of the lens after which the hard lens nucleus is liqui?ed ultrasonically. A replacement lens is inserted into the empty lens bag (see diagram). Patients usually return to their normal activities within a few days of the operation. A recent development under test in the USA for children requiring cataract operations is an intra-ocular ?exible implant whose magnifying power can be altered as a child develops, thus precluding the need for a series of corrective operations as happens now.
Chalazion A ?rm lump in the eyelid relating to a blocked meibomian gland, felt deep within the lid. Treatment is not always necessary; a proportion spontaneously resolve. There can be associated infection when the lid becomes red and painful requiring antibiotic treatment. If troublesome, the chalazion can be incised under local anaesthetic.
Conjunctivitis In?ammation of the conjunctiva (see EYE) which may affect one or both eyes. Typically the eye is red, itchy, sticky and gritty but is not usually painful. Redness is not always present. Conjunctivitis can occasionally be painful, particularly if there is an associated keratitis (see below) – for example, adenovirus infection, herpetic infection.
The cause can be infective (bacteria, viruses or CHLAMYDIA), chemical (e.g. acids, alkalis) or allergic (e.g. in hay fever). Conjunctivitis may also be caused by contact lenses, and preservatives or even the drugs in eye drops may cause conjunctival in?ammation. Conjunctivitis may addtionally occur in association with other illnesses – for example, upper-respiratory-tract infection, Stevens-Johnson syndrome (see ERYTHEMA – erythema multiforme) or REITER’S SYNDROME. The treatment depends on the cause. In many patients acute conjunctivitis is self-limiting.
Dacryocystitis In?ammation of the lacrimal sac. This may present acutely as a red, painful swelling between the nose and the lower lid. An abscess may form which points through the skin and which may need to be drained by incision. Systemic antibiotics may be necessary. Chronic dacryocystitis may occur with recurrent discharge from the openings of the tear ducts and recurrent swelling of the lacrimal sac. Obstruction of the tear duct is accompanied by watering of the eye. If the symptoms are troublesome, the patient’s tear passageways need to be surgically reconstructed.
Ectropion The lid margin is everted – usually the lower lid. Ectropion is most commonly associated with ageing, when the tissues of the lid become lax. It can also be caused by shortening of the skin of the lids such as happens with scarring or mechanical factors – for example, a tumour pulling the skin of the lower lid downwards. Ectropion tends to cause watering and an unsightly appearance. The treatment is surgical.
Entropion The lid margin is inverted – usually the lower lid. Entropion is most commonly associated with ageing, when the tissues of the lid become lax. It can also be caused by shortening of the inner surfaces of the lids due to scarring – for example, TRACHOMA or chemical burns. The inwardly directed lashes cause irritation and can abrade the cornea. The treatment is surgical.
Episcleritis In?ammation of the EPISCLERA. There is usually no apparent cause. The in?ammation may be di?use or localised and may affect one or both eyes. It sometimes recurs. The affected area is usually red and moderately painful. Episcleritis is generally not thought to be as painful as scleritis and does not lead to the same complications. Treatment is generally directed at improving the patient’s symptoms. The in?ammation may respond to NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) or topical CORTICOSTEROIDS.
Errors of refraction (Ametropia.) These will occur when the focusing power of the lens and cornea does not match the length of the eye, so that rays of light parallel to the visual axis are not focused at the fovea centralis (see EYE). There are three types of refractive error: HYPERMETROPIA or long-sightedness. The refractive power of the eye is too weak, or the eye is too short so that rays of light are brought to a focus at a point behind the retina. Longsighted people can see well in the distance but generally require glasses with convex lenses for reading. Uncorrected long sight can lead to headaches and intermittent blurring of vision following prolonged close work (i.e. eye strain). As a result of ageing, the eye becomes gradually long-sighted, resulting in many people needing reading glasses in later life: this normal process is known as presbyopia. A particular form of long-sightedness occurs after cataract extraction (see above). MYOPIA(Short sight or near sight.) Rays of light are brought to a focus in front of the retina because the refractive power of the eye is too great or the eye is too short. Short-sighted people can see close to but need spectacles with concave lenses in order to see in the distance. ASTIGMATISMThe refractive power of the eye is not the same in each meridian. Some rays of light may be focused in front of the retina while others are focused on or behind the retina. Astigmatism can accompany hypermetropia or myopia. It may be corrected by cylindrical lenses: these consist of a slice from the side of a cylinder (i.e. curved in one meridian and ?at in the meridian at right-angles to it).
Keratitis In?ammation of the cornea in response to a variety of insults – viral, bacterial, chemical, radiation, or mechanical trauma. Keratitis may be super?cial or involve the deeper layers, the latter being generally more serious. The eye is usually red, painful and photophobic. Treatment is directed at the cause.
Nystagmus Involuntary rhythmic oscillation of one or both eyes. There are several causes including nervous disorders, vestibular disorders, eye disorders and certain drugs including alcohol.
Ophthalmia In?ammation of the eye, especially the conjunctiva (see conjunctivitis, above). Ophthalmia neonatorum is a type of conjunctivitis that occurs in newborn babies. They catch the disease when passing through an infected birth canal during their mother’s labour (see PREGNANCY AND LABOUR). CHLAMYDIA and GONORRHOEA are the two most common infections. Treatment is e?ective with antibiotics: untreated, the infection may cause permanent eye damage.
Pinguecula A benign degenerative change in the connective tissue at the nasal or temporal limbus (see EYE). This is visible as a small, ?attened, yellow-white lump adjacent to the cornea.
Pterygium Overgrowth of the conjunctival tissues at the limbus on to the cornea (see EYE). This usually occurs on the nasal side and is associated with exposure to sunlight. The pterygium is surgically removed for cosmetic reasons or if it is thought to be advancing towards the visual axis.
Ptosis Drooping of the upper lid. May occur because of a defect in the muscles which raise the lid (levator complex), sometimes the result of ageing or trauma. Other causes include HORNER’S SYNDROME, third cranial nerve PALSY, MYASTHENIA GRAVIS, and DYSTROPHIA MYOTONICA. The cause needs to be determined and treated if possible. The treatment for a severely drooping lid is surgical, but other measures can be used to prop up the lid with varying success.
Retina, disorders of The retina can be damaged by disease that affects the retina alone, or by diseases affecting the whole body.
Retinopathy is a term used to denote an abnormality of the retina without specifying a cause. Some retinal disorders are discussed below. DIABETIC RETINOPATHY Retinal disease occurring in patients with DIABETES MELLITUS. It is the commonest cause of blind registration in Great Britain of people between the ages of 20 and 65. Diabetic retinopathy can be divided into several types. The two main causes of blindness are those that follow: ?rst, development of new blood vessels from the retina, with resultant complications and, second, those following ‘water logging’ (oedema) of the macula. Treatment is by maintaining rigid control of blood-sugar levels combined with laser treatment for certain forms of the disease – in particular to get rid of new blood vessels. HYPERTENSIVE RETINOPATHY Retinal disease secondary to the development of high blood pressure. Treatment involves control of the blood pressure (see HYPERTENSION). SICKLE CELL RETINOPATHY People with sickle cell disease (see under ANAEYIA) can develop a number of retinal problems including new blood vessels from the retina. RETINOPATHY OF PREMATURITY (ROP) Previously called retrolental ?broplasia (RLF), this is a disorder affecting low-birth-weight premature babies exposed to oxygen. Essentially, new blood vessels develop which cause extensive traction on the retina with resultant retinal detachment and poor vision. RETINAL ARTERY OCCLUSION; RETINAL VEIN OCCLUSION These result in damage to those areas of retina supplied by the affected blood vessel: the blood vessels become blocked. If the peripheral retina is damaged the patient may be completely symptom-free, although areas of blindness may be detected on examination of ?eld of vision. If the macula is involved, visual loss may be sudden, profound and permanent. There is no e?ective treatment once visual loss has occurred. SENILE MACULAR DEGENERATION (‘Senile’ indicates age of onset and has no bearing on mental state.) This is the leading cause of blindness in the elderly in the western world. The average age of onset is 65 years. Patients initially notice a disturbance of their vision which gradually progresses over months or years. They lose the ability to recognise ?ne detail; for example, they cannot read ?ne print, sew, or recognise people’s faces. They always retain the ability to recognise large objects such as doors and chairs, and are therefore able to get around and about reasonably well. There is no e?ective treatment in the majority of cases. RETINITIS PIGMENTOSAA group of rare, inherited diseases characterised by the development of night blindness and tunnel vision. Symptoms start in childhood and are progressive. Many patients retain good visual acuity, although their peripheral vision is limited. One of the characteristic ?ndings on examination is collections of pigment in the retina which have a characteristic shape and are therefore known as ‘bone spicules’. There is no e?ective treatment. RETINAL DETACHMENTusually occurs due to the development of a hole in the retina. Holes can occur as a result of degeneration of the retina, traction on the retina by the vitreous, or injury. Fluid from the vitreous passes through the hole causing a split within the retina; the inner part of the retina becomes detached from the outer part, the latter remaining in contact with the choroid. Detached retina loses its ability to detect light, with consequent impairment of vision. Retinal detachments are more common in the short-sighted, in the elderly or following cataract extraction. Symptoms include spots before the eyes (?oaters), ?ashing lights and a shadow over the eye with progressive loss of vision. Treatment by laser is very e?ective if caught early, at the stage when a hole has developed in the retina but before the retina has become detached. The edges of the hole can be ‘spot welded’ to the underlying choroid. Once a detachment has occurred, laser therapy cannot be used; the retina has to be repositioned. This is usually done by indenting the wall of the eye from the outside to meet the retina, then making the retina stick to the wall of the eye by inducing in?ammation in the wall (by freezing it). The outcome of surgery depends largely on the extent of the detachment and its duration. Complicated forms of detachment can occur due to diabetic eye disease, injury or tumour. Each requires a specialised form of treatment.
Scleritis In?ammation of the sclera (see EYE). This can be localised or di?use, can affect the anterior or the posterior sclera, and can affect one or both eyes. The affected eye is usually red and painful. Scleritis can lead to thinning and even perforation of the sclera, sometimes with little sign of in?ammation. Posterior scleritis in particular may cause impaired vision and require emergency treatment. There is often no apparent cause, but there are some associated conditions – for example, RHEUMATOID ARTHRITIS, GOUT, and an autoimmune disease affecting the nasal passages and lungs called Wegener’s granulomatosis. Treatment depends on severity but may involve NON-STEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS), topical CORTICOSTEROIDS or systemic immunosuppressive drugs.
Stye Infection of a lash follicle. This presents as a painful small red lump at the lid margin. It often resolves spontaneously but may require antibiotic treatment if it persists or recurs.
Sub-conjunctival haemorrhage Haemorrhage between the conjunctiva and the underlying episclera. It is painless. There is usually no apparent cause and it resolves spontaneously.
Trichiasis Inward misdirection of the lashes. Trichiasis occurs due to in?ammation of or trauma to the lid margin. Treatment involves removal of the patient’s lashes. Regrowth may be prevented by electrolysis, by CRYOTHERAPY to the lid margin, or by surgery.
For the subject of arti?cial eyes, see under PROSTHESIS; also GLAUCOMA, SQUINT and UVEITIS.... eye, disorders of
Common warts (verruca vulgaris) are seen mainly in children and young adults on the backs of the ?ngers and hands, and less often on the knees, face or scalp. They may be single or numerous and range from 1 mm to 10 mm or more in size. Untreated, they often resolve spontaneously after weeks or months. They may be occupationally contracted by butchers and meat-handlers.
Plane warts (verruca plana) are small, ?at-topped, yellowish papules seen mainly on the backs of the hands, wrists and face in young people. They may persist for years.
Digitate warts (verruca digitata) are ?nger- or thread-like warts up to 5 mm in length with a dark rough tip. They tend to grow on the eyelids or neck.
Plantar warts (verruca plantaris) occur on the soles of the feet, most commonly in older children, adolescents and young adults. Spread by walking barefoot in swimming pools, changing rooms, etc., these warts may appear as minor epidemics in institutions, such as schools. They are ?attened, yellow-white discrete lesions in the sole or heel, tender when squeezed. Multiple black points in the wart are thrombosed capillaries. Occasionally, aggregates of plantar warts form a mosaic-like plaque, especially in chronically warm, moist feet.
Genital warts are sexually transmitted. In the male they occur on the shaft of the PENIS and on the PREPUCE or around the anus. In women they occur around the entrance to the VAGINA and LABIA minora. Genital warts vary from 1–2 mm pink papules to ?orid, cauli?ower-like masses. Pregnancy facilitates their development.
Mucosal warts may develop on the mucous membranes of the mouth.
Laryngeal warts may be found in children whose mothers had genital warts (see above) at the time of delivery. Some subtypes of genital wart can infect the uterine cervix (see UTERUS), causing changes which may lead eventually to cancer.
Treatment CRYOTHERAPY – freezing with liquid nitrogen – is the principal weapon against all types of warts, but curettage (scraping out the wart with a CURETTE) and cauterisation (see ELECTROCAUTERY) or LASER therapy may be required for resistant warts. Genital warts may respond to local application of PODOPHYLLIN preparations. Sexual partners should be examined and treated if necessary. Finally, treatment of warts should not be more onerous or painful than the disease itself, since spontaneous resolution is so common.... warts
Treatment is with antibiotics or with antiviral drugs. If symptoms persist, the inflamed area of cervix may be cauterized by electrocoagulation, cryotherapy, or laser treatment.... cervicitis
Acute pain is caused by internal or external injury or disease. It warns the individual that harm or damage is occurring and stimulates them to take avoiding or protective action. With e?ective treatment of disease or injury and/or the natural healing process, the pain resolves – although some acute pain syndromes may develop into chronic pain (see below). Stimuli which are su?ciently intense potentially to damage tissue will cause the stimulation of speci?c receptors known as NOCICEPTORS. Damage to tissues releases substances which stimulate the nociceptors. On the surface of the body there is a high density of nociceptors, and each area of the body is supplied by nerves from a particular spinal segment or level: this allows the brain to localise the source of the pain accurately. Pain from internal structures and organs is more di?cult to localise and is often felt in some more super?cial structure. For example, irritation of the DIAPHRAGM is often felt as pain in the shoulder, as the nerves from both structures enter the SPINAL CORD at the same level (often the structures have developed from the same parts of the embryo). This is known as referred pain.
The impulses from nociceptors travel along nerves to the spinal cord. Within this there is modulation of the pain ‘messages’ by other incoming sensory modalities, as well as descending input from the brain (Melzack and Walls’ gate-control theory). This involves morphine-like molecules (the ENDORPHINS and ENKEPHALINS) amongst many other pain-transmitting and pain-modulating substances. The modi?ed input then passes up the spinal cord through the thalamus to the cerebral cortex. Thus the amount of pain ‘felt’ may be altered by the emotional state of the individual and by other incoming sensations. Once pain is perceived, then ‘action’ is taken; this involves withdrawal of the area being damaged, vocalisation, AUTONOMIC NERVOUS SYSTEM response and examination of the painful area. Analysis of the event using memory will occur and appropriate action be taken to reduce pain and treat the damage.
Chronic pain may be de?ned in several ways: for example, pain resistant to one month’s treatment, or pain persisting one month beyond the usual course of an acute illness or injury. Some doctors may also arbitrarily choose the ?gure of six months. Chronic pain di?ers from acute pain: the physiological response is di?erent and pain may either be caused by stimuli which do not usually cause the perception of pain, or may arise within nerves or the central nervous system with no apparent external stimulation. It seldom has a physiological protective function in the way acute pain has. Also, chronic pain may be self-perpetuating: if individuals gain a psychological advantage from having pain, they may continue to do so (e.g. gaining attention from family or health professionals, etc.). The nervous system itself alters when pain is long-standing in such a way that it becomes more sensitive to painful inputs and tends to perpetuate the pain.
Treatment The treatment of pain depends upon its nature and cause. Acute pain is generally treated by curing the underlying complaint and prescribing ANALGESICS or using local anaesthetic techniques (see ANAESTHESIA – Local anaesthetics). Many hospitals now have acute pain teams for the management of postoperative and other types of acute pain; chronic pain is often treated in pain clinics. Those involved may include doctors (in Britain, usually anaesthetists), nurses, psychologists and psychiatrists, physiotherapists and complementary therapists. Patients are usually referred from other hospital specialists (although some may be referred by GPs). They will usually have been given a diagnosis and exhausted the medical and surgical treatment of their underlying condition.
All the usual analgesics may be employed, and opioids are often used in the terminal treatment of cancer pain.
ANTICONVULSANTS and ANTIDEPRESSANT DRUGS are also used because they alter the transmission of pain within the central nervous system and may actually treat the chronic pain syndrome.
Many local anaesthetic techniques are used. Myofascial pain – pain affecting muscles and connective tissues – is treated by the injection of local anaesthetic into tender spots, and nerves may be blocked either as a diagnostic procedure or by way of treatment. Epidural anaesthetic injections are also used in the same way, and all these treatments may be repeated at intervals over many months in an attempt to cure or at least reduce the pain. For intractable pain, nerves are sometimes destroyed using injections of alcohol or PHENOL or by applying CRYOTHERAPY or radiofrequency waves. Intractable or terminal pain may be treated by destroying nerves surgically, and, rarely, the pain pathways within the spinal cord are severed by cordotomy (though this is generally only used in terminal care).
ACUPUNCTURE and TRANSCUTANEOUS ELECTRICAL NERVE STIMULATION (TENS) are used for a variety of pain syndromes, particularly myofascial or musculoskeletal pain. It is thought that they work by increasing the release of endorphins and enkephalins (see above). It is possible to implant electrodes within the epidural space to stimulate directly the nerves as they traverse this space before passing into the spinal cord.
Physiotherapy is often used, particularly in the treatment of chronic backache, where pain may be reduced by improving posture and strengthening muscles with careful exercises. Relaxation techniques and psychotherapy are also used both to treat chronic pain and to help patients cope better with their disability.
Some types of chronic pain are caused by injury to sympathetic nerves or may be relieved by interrupting conduction in sympathetic nerves. This may be done in several ways. The nerves may be blocked using local anaesthetic or permanently destroyed using alcohol, phenol or by surgery.
Many of these techniques may be used in the management of cancer pain. Opioid drugs are often used by a variety of routes and methods, and management of these patients concentrates on the control of symptoms and on providing a good quality of life.... pain
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