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20
Skin, nails and hair
and fungal infection (tinea and candidiasis). The
established routine use of the dermatoscope has
become essential in the assessment of pigmented
skin lesions and aids in diagnosis of skin malignancy,
especially malignant melanoma.
Scabies
Scabies is caused by the mite Acarus (Sarcoptes)
scabei. The female is larger than the male and
burrows in the epidermis, depositing eggs. These
burrows should be looked for between the fingers,
on the hands or wrists and on the sides of the feet.
They can be recognized with the naked eye as short
dark lines terminating in a shining spot of skin. The
eggs lie in the dark line, the mite in the shining spot.
It may be picked out by means of a flat surgical
needle and placed on a microscope slide for more
detailed examination.
Pediculosis
Three forms of pediculosis or louse infestation occur:
Pediculus capitis on the head, Pediculus corporis on the
trunk and Pediculus pubis on the pubic and axillary
hairs. The eggs or nits of P. pubis and P. capitis adhere
to the hairs. From their position on the hairs, one can
judge roughly the duration of the condition: they are
fixed at first near the root of the hair and are carried
up as the hair grows, so the higher the nits are, the
longer the pediculi have been present. P. corporis
should be looked for in the seams of the clothes,
especially where the clothes come into contact
with the skin, for example over the shoulders. The
bites of the parasite produce haemorrhagic spots,
each with a dark centre and a paler areola. Marks of
scratching should be looked for on parts accessible
to the patient’s nails. P. pubis is venereally acquired
and causes intense pubic itching. The nits are laid
on the pubic hair and the lice themselves are easily
visible. P. corporis is seen only in the grossly deprived,
living in rough conditions of war or social upheaval.
In contrast, P. capitis is common in school children,
however clean they and their families may be, and is
endemic in many schools.
Fungal infections
Fungus may grow in the skin, nails or hair and can
cause disease (ringworm or tinea), for example
athlete’s foot (tinea pedis).
The most common sites of fungal infection are the
skin between the toes (tinea pedis) and the soles of
the feet and the groin (tinea cruris). The lesions may
be scaly or vesicular, tending to spread in a ring form
with central healing (Fig. 20.28); macerated, dead,
white, offensive- smelling epithelium is found in the
intertriginous areas, such as the toe clefts.
Nail discolouration, deformity, hypertrophy and
abnormal brittleness may result from fungus infection
(tinea unguium).
Ringworm of the scalp (tinea capitis) is most
common in children. It presents as round or oval
areas of baldness covered with short, lustreless
broken- off hair stumps. These hair stumps may
fluoresce bright green under Wood’s light. Some
fungi do not fluoresce with Wood’s light, however,
and these can be detected only by microscopy and
culture (Figs 20.29 and 20.30).
Microscopic examination for fungus infection
Scales from the active edge of a lesion are scraped
off lightly with a scalpel or the roofs of vesicles are
snipped off with scissors. The material is placed in a
drop of 10% to 20% aqueous potassium hydroxide
solution on a microscope slide, covered with a
coverslip and left for 30 minutes to clear. It is then
examined under the light microscope with the
8- mm or 4- mm objective using low illumination.
The mycelia are recognized as branching, refractile
threads that boldly transgress the outlines of the
squamous cells. Nails are examined in much the same
way, but it is necessary to break up the snippings
Box 20.12
Dermatology blood investigations
Blood test Clinical example
Full blood count (FBC) Pruritus
Ferritin and iron studies Hail and nail
Biochemistry renal and liver
function
Streptococcal serology Cellulitis
Autoantibodies Autoimmune disorders
Hepatitis screen Lichen planus
HSV 1 and 2 serology Erythema multiforme
Syphilis serology Secondary syphilis
HIV Persistent infections
HLA typing Dermatitis herpetiformis
DNA analysis Epidermolysis bullosa
Pruritus
Figure 20.28 Tinea rubrum (ringworm infection).
Figure 20.29 Lactophenol blue preparation showing macronidia
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of Microsporum species, isolated from skin scrapings from a
patient with ringworm.
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Skin, nails and hair
Figure 20.31 Disposable punch skin biopsy, especially useful
where minimal scarring is desirable.
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Figure 20.30 Kerion owing to localized deep dermatophyte
infection in the scalp.
and shavings into small fragments. These are either
heated in potassium hydroxide or are left to clear in
it overnight before being examined.
A scalp lesion is cleaned with 70% alcohol or
with 1% cetrimide; infected stumps and scales are
removed by scraping with a scalpel. The hairs are
cleaned in potassium hydroxide in the same way
as skin scales. Examination under the microscope
reveals spores on the outside of the hair roots and
mycelia inside the hair substance. The species of
fungus responsible may be established by culture on
Sabouraud’s glucose- agar.
Wood’s light
A Wood’s light lamp emits long- wave ultraviolet
light at a peak of 360 nm. Wood’s light examination
is performed in a darkened room and is useful to
identify the fluorescence of fungi and corynebacterial
infection (erythrasma), elevated porphyrins in urine
or in the localization of pigmentary abnormalities.
Contact allergy patch testing
Contact allergy patch testing is an important and
valuable tool for the diagnosis of suspected allergic
Figure 20.32 A 4- mm punch diagnostic biopsy.
dermatitis owing to contact (contact dermatitis).
The formulation of the allergens is critical, and
various standard contact allergen test batteries have
been developed in different countries and clinics
to include the most common culprits. Patch testing
is simple, but the results are not always easy to
interpret. Allergens are placed in shallow aluminium
1- cm2 wells and applied in strips to the patient’s
back for 48 hours for initial reading and a second
reading at 96 hours. This ensures that any delayedtype hypersensitivity (e.g. Coomb’s type IV reaction
to an allergen) can be identified.
Skin biopsy
Biopsy of the skin is used not only to excise benign
and malignant tumours but also to identify the
nature of reactive and/or inflammatory lesions.
Punch biopsy (Figs 20.31 and 20.32) is popular
because of its convenience and its minimal scarring.
The biopsy can be studied by conventional histology,
often supplemented by immunofluorescence and
sometimes immunohistochemistry or molecular
biology, to identify specific proteins or genetic
abnormalities. Skin biopsy of fresh tissue can be
sent for the microbiology of unusual infections and
is increasingly used in diagnosis and in assessing the
progress of skin diseases.
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BASIC SYSTEMS
Eyes
Andrew Coombes
21
Introduction
Although proportionally a greater contribution towards
the diagnosis of ophthalmic disorders is made by the
examination compared with the history, it is important
to obtain a detailed account of the presenting complaint and associated visual symptoms from the patient
with an ocular problem.
History
Disturbance of vision, the most important ocular
symptom, may be sudden or gradual, unilateral or
bilateral, and lead to loss of central vision or partial
field loss. Simultaneous, bilateral visual symptoms are
usually owing to disease in optic pathways at or posterior to the optic chiasm. Sudden visual disturbance
should be assessed urgently. Visual hallucinations
may be formed or unformed. Some visual symptoms
have particular significance (Table 21.1). For exam-
ple, haloes around lights occur in acute angle- closure
glaucoma caused by corneal oedema. ‘Floaters’ and
flashes (photopsia) are indicative of vitreous or retinal disorders, respectively. The latter may also cause
objects to appear smaller (micropsia), larger (macropsia) or distorted (metamorphopsia). Disorders of
ocular movement may cause double vision (diplopia)
or visual blurring. Are the visual symptoms binocular
or monocular? Are they related to eye movements?
Other common presentations include a red eye,
abnormal lid position, protrusion of the globe and
pupillary or eyelid abnormality. Ocular pain is often
associated with a red eye (Table 21.2). Ocular pain
owing to a foreign body may be described as ‘a gritty
sensation’ in the eye, often worsened by blinking. It
may be associated with sensitivity to light (photophobia) but this, particularly in conjunction with
ocular aching, usually indicates serious corneal or intraocular disease. Severe ocular pain with vomiting
may indicate acute glaucoma. Migraine often presents with bilateral visual symptoms and headache.
Raised intracranial pressure and giant cell arteritis
should also be considered when headache is associated with visual symptoms. Pain may be referred to
the eye because of neighbouring disease, for example
sinusitis. Excessive tear production (lacrimation) associated with discomfort may indicate ocular surface
disease. There may be abnormal secretions from the
eye, such as mucus or pus. With insufficient tears, the
eye typically feels dry, whereas a painless overflow of
tears (epiphora) typically indicates blockage of the
lacrimal drainage system.
Note any previous ophthalmic history, such as a
squint in childhood, and any pre- existing poor vision
or previous ocular injury or surgery. Note what type
of glasses or contact lenses are worn: extended- wear
soft contact lenses are associated with an increased
risk of corneal infection. The family history may
reveal glaucoma, decreased visual acuity, colour
blindness, squint or neurological disease associated
with visual loss. In addition to the ocular history, the
medical, drug and social histories are important.
Examination
Eye examination is part of the cranial nerve examination. It includes ocular movements (cranial nerves
III, IV and VI), corneal sensation (ophthalmic division of the trigeminal nerve) and eye closure (VII).
Assess the optic (II) nerve by testing visual acuity,
colour vision, the visual fields and the pupillary light
reaction. Inspect the optic nerve head (the optic disc
and cup) with the ophthalmoscope. Detailed examination of the anterior segment of the eye requires
use of the slit lamp which, with additional equipment, can also be used to test the intraocular pressure (IOP) and examine the retina.
Visual acuity
Visual acuity is most reliably tested at 6 m (20 ft)
using a standard chart such as the Snellen (Fig. 21.1A)
or Log MAR chart (Fig. 21.1B). Tests of acuity in near
vision are portable, but limited by age- related loss
of accommodation (presbyopia), which necessitates
refractive correction in older patients. These use test
types of varying sizes, based on the point system of
the printers (Fig. 21.2), and the smallest type that can
be read comfortably at a distance of 33 cm is recorded
(normally N4.5 or N5 type).
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Table 21.1 Sudden visual disturbance
Diagnosis History: visual symptoms
Vascular Ocular Amaurosis fugax Transient (minutes), unilateral
Retinal artery/vein occlusion Permanent, unilateral, often associated with systemic vascular
disease (e.g. ischaemic heart disease, hypertension, diabetes)
Non- arteritic ischaemic optic
neuropathy (NAION)
Arteritic ischaemic optic
neuropathy (AAION)
Papilloedema/optic disc
swelling
Cortical Transient ischaemic attack
(TIA)
Migraine Transient, bilateral, typically followed by nausea and headache
Cerebrovascular accident
(CVA)
Non- vascular Vitreous Posterior vitreous
detachment (PVD)
Vitreous haemorrhage Transient (weeks), unilateral, multiple floaters, central vision
Retina Wet age- related macular
degeneration (AMD)
Retinal detachment Progressive, unilateral field loss, central vision reduced if macula
Optic nerve Optic neuritis Transient (months), unilateral, may be associated with features of
Acute compression Progressive, unilateral, bilateral if chiasm involved (e.g. pituitary
Pseudo Suddenly noticed Unilateral gradual visual loss from (e.g. dry AMD or cataract)
Functional Bilateral or unilateral; diagnosis of exclusion
Permanent, unilateral, often associated with systemic vascular
disease (e.g. ischaemic heart disease, hypertension, diabetes)
Permanent, unilateral, typically associated with symptoms of
giant cell arteritis (e.g. temporal headache/tenderness, jaw
claudication, features of polymyalgia rheumatica)
Transient (seconds), bilateral visual obscurations, often
precipitated by coughing or bending
Transient (minutes), bilateral, associated with systemic vascular
disease (e.g. ischaemic heart disease, hypertension, diabetes,
etc.)
Permanent homonymous field defect, may be preceded by TIA
symptoms; note central acuity usually preserved except in
bilateral occipital lobe infarction
Transient (weeks), unilateral, floaters, occasional photopsia,
central vision normal
typically reduced
Progressive, unilateral central visual distortion (metamorphopsia)
This condition is also known as exudative or neovascular AMD
involved, often associated with symptoms of PVD
multiple sclerosis
apoplexy (infarction of a pituitary tumour))
Snellen distance vision
On the Snellen chart, each line of letters is designated by a number that corresponds to the distance
at which those letters can be read by someone with
‘normal’ distance vision. For example, the largest
letter, at the top of the chart—designated 60—
would be read at 60 m by a person with ‘normal’
vision.
Technique
The patient sits or stands 6 m (20 ft) from the chart.
Where space is limited, a mirror may be used 3 m
from both patient and chart, with the patient facing
away from the chart and reading the letters in the
mirror, giving a total of 6 m. However, increasingly,
electronic computer screens are being used and the
letter size can be adjusted to allow test distance to be
varied between 3 and 6 m. Distance glasses should
be worn if necessary and each eye tested separately.
The patient should read line by line from the top of
the chart. If a patient cannot see the largest letter,
designated 60, then the test distance should be
reduced. If at 1 m the 60 letter cannot be seen, assess
the following:
Counting fingers held up at about 1 m (CFs)
Hand movements (HMs)
Perception of light (PL)
When testing low vision, ensure that the eye not
being tested is completely covered. If a patient cannot read 6/6 or better in either eye, check the vision
again using a pinhole occluder (Fig. 21.3). This test
distinguishes patients with poor vision owing to
refractive error from those who have ocular or neurological conditions. In a myopic (short- sighted) eye,
the rays of light are focused in front of the retina.
In hypermetropia (long- sightedness), light is focused
behind the eye, because the eye is abnormally short.
In astigmatism, the cornea is not uniformly curved
and light is not focused evenly on the retina. When
using a pinhole, only the central rays of light pass
through to the retina and refractive errors are significantly reduced.
Table 21.2 Red eye
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Diagnosis History Examination
Subconjunctival
haemorrhage
Viral conjunctivitis FB sensation, watering, no visual loss or photophobia
Bacterial
conjunctivitis
Allergic
conjunctivitis
Iritis (anterior
uveitis)
Acute angleclosure glaucoma
Episcleritis Mild discomfort, tenderness, no visual loss or photophobia,
Scleritis Significant aching pain, tender, photophobia, occasionally
Bacterial keratitis FB sensation, watering/discharge, visual loss, photophobia
Herpetic viral
keratitis
FB, foreign body; PMH, past medical history; URTI, upper respiratory tract infection.
Typically asymptomatic, spontaneous
May be associated with trauma
Recent contact with person with red eye or URTI?
FB sensation, discharge, no visual loss or photophobia Bilateral, prominent inflamed conjunctival
Itch, watering, no visual loss or photophobia, history of
atopy
Reduced vision, aching sensation, photophobia
PMH or systemic enquiry may elicit underlying disease
Severe pain, haloes/rainbows around lights, reduced
vision, hypermetropic, elderly
young adult, otherwise fit and well
reduced vision, systemic enquiry may elicit underlying
disease
Pre- existing ocular surface disease, recent trauma or
contact lens wear?
FB sensation, watering/discharge, visual loss, photophobia
Cold sores or ophthalmic shingles?
Unilateral (except some trauma), contiguous
red area
Bilateral, prominent inflamed conjunctival
vessels and follicles, enlarged tender
preauricular lymph node
vessels, mucopus
Bilateral, prominent inflamed conjunctival
vessels and follicles
Unilateral, prominent pericorneal vessels,
small pupil, aqueous cells and flare (protein)
(at slit lamp), hypopyon
Unilateral, pericorneal prominent vessels,
semidilated (oval) pupil, corneal oedema,
shallow anterior chamber (slit lamp)
Unilateral, typically sectorial prominent
inflamed subconjunctival vessels (may also be
nodular or diffuse)
Unilateral, typically sectorial prominent
inflamed deep scleral vessels (may also be
nodular or diffuse)
Unilateral, opacity in cornea (slit lamp) stains
with fluorescein
Unilateral, branching linear dendrite(s) on
cornea (slit lamp) stains with fluorescein
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Recording visual acuity
The top figure, the numerator, records the distance
of the subject from the test chart—usually 6 m. The
bottom figure records the line read by the patient.
The normal person can read the line designated 6 at
6 m (i.e. 6/6 (20/20) vision).
Record a mistake of one letter in a line as ‘−1’
and a single letter read from the next smaller line as
‘+1’. Thus, if all except one of the letters on the line
designated 6 are read correctly, the visual acuity is
recorded 6/6 −1. If only one letter on that line is read
correctly, the visual acuity is recorded 6/9 +1. Like
all ophthalmic findings except visual fields, right eye
visual acuity is traditionally written on the left side
of the page (as the patient’s eye appears to you) and
vice versa. Whether the patient was using glasses,
pinhole (ph) or was unaided (ua) is recorded in the
middle (Fig. 21.4).
Log MAR charts
Increasingly, Snellen acuity tests are being replaced
by use of a Log MAR chart, which superficially
appears similar to a Snellen chart but addresses its
problems, namely different number of letters per
line, irregular spacing between letters/lines and
unequal graduation from one line to the other. On a
Log MAR chart each letter has a score value of 0.02
log units with 5 letters per line (each line therefore
scores 0.1 log units). 6/6 is equivalent to Log MAR
score 0.00 and 6/60 is 1.00. Each letter read contributes to the score; for example, 6/6−1 would be
recorded as 0.02. The digital output is also helpful
for research and audit purposes.
Colour vision
Tests of colour vision are important because colour
perception, especially for red, is affected in optic
nerve disease before changes in visual acuity can
be detected. Show the patient a red target one eye
at a time (any bright red target can be used) and
ask if there is a difference between the eyes. In the
affected eye, red appears ‘washed out’ (desaturated).
Acquired defects of colour vision may also occur in
macular disease. The Ishihara test (Fig. 21.5) was
devised to test for congenital colour anomalies (colour
blindness), but is often used to assess acquired visual
disorders. Most inherited colour blindness occurs in
males (sex- linked recessive inheritance). It ranges
from total colour blindness (monochromatopsia) to
subtle confusion between colours, typically between
red and green. About 8% of men and 0.5% of women
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lesions anterior to the chiasm (i.e. in the optic nerves
or retinae). Characteristic field defects (scotoma)
occur in glaucoma, when damage to nerve fibres
occurs at the optic disc, typically at the inferior or
superior aspect of the optic cup. Fundoscopy shows
an increase in vertical length of the optic cup (see
later in the chapter for details about how to examine the fundi) and field loss is arc- shaped (arcuate
scotoma). If both the inferior and superior fields are
involved, a ring- shaped scotoma develops. Untreated
glaucoma results in loss of the peripheral field so that
only a small central island of vision remains (tunnel
vision). Computerized perimetry is useful in identifying early visual field loss. The Humphrey field test
analyser (Carl Zeiss), for example, provides statistical information indicating the reliability of the test
in comparison with a group of age- matched controls
(Fig. 21.6).
Pupils
Examination of the pupils in neurology is discussed
in Chapter 16. In ophthalmic practice, there are
three key aspects to pupil examination: size, shape
and reactions.
Figure 21.1 (A) Snellen chart for testing distance vision. (B) Log
MAR chart for testing distance vision.
in the UK have congenital colour perception defects.
Blue/yellow deficiencies and total colour blindness
are uncommon.
Visual field testing
Visual field testing is described in Chapter 16. Field
defects may affect one or both eyes. Symmetrical
bilateral (homonymous) field defects are characteristic of lesions posterior to the optic chiasm, and
asymmetrical field defects are usually caused by
Pupil size: anisocoria
In 12% of normal individuals, the pupils are slightly
unequal, particularly in bright light (anisocoria),
but in these subjects they react normally. Abnormal pupils dilate and constrict abnormally, and the
degree of anisocoria varies with the ambient illumination. However, it is often difficult to decide which
pupil is abnormal. In the absence of local eye disease,
a small pupil may be owing to paralysis of the dilator
pupillae muscle (sympathetic innervated), part of
Horner’s syndrome (Fig. 21.7), in which anisocoria is
more pronounced in low ambient light. An enlarged
pupil suggests a parasympathetic lesion, which may
be preganglionic in oculomotor lesions or postganglionic as in the tonic pupil of Adie’s syndrome.
Adie’s tonic pupil tends to be dilated in bright light
and is very slow to react. A feature of both parasympathetic and sympathetic lesions is denervation
hypersensitivity caused by upregulation of receptors
at the neuromuscular junction (adrenergic in sympathetic and cholinergic in parasympathetic). This is
the basis of pharmacological pupil testing. In both
pre- and postganglionic parasympathetic blockade,
the pupil is supersensitive to weak cholinergic drops
(e.g. pilocarpine 0.1%). In sympathetic block, dilute
adrenergic agonists, such as phenylephrine 1%, are
unreliable, so the uptake blocker, cocaine 4%, is
used. This dilates normal pupils but has no effect in
pre- or postganglionic lesions. Hydroxyamfetamine
1% causes noradrenaline (norepinephrine) release
from normal or intact postganglionic neurons and
allows pre- and postganglionic lesions to be distinguished (the synapse is located in the superior
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Eyes
Figure 21.2 Near vision chart based on
the point system of the printer.
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cervical ganglion). In complex pupil abnormalities,
for example bilateral Horner’s syndrome, infrared
pupil imaging can be valuable. Causes of anisocoria
are highlighted in Box 21.1. In congenital Horner’s
syndrome, the affected iris is depigmented and
appears blue.
Pupil reactions: afferent and central defects
The swinging light test is used to detect a relative
afferent pupillary defect (RAPD) resulting from
retinal or optic nerve disease. The test loses sensitivity
in symmetrical bilateral optic nerve disease, but this is
rare; in most bilateral cases the defect will be detected
on the more abnormal side. RAPD is often associated
with reduced vision, but if central vision is retained,
the acuity will be normal, although severe peripheral
field damage may cause RAPD. In neurosyphilis, the
pupils are small and irregular and show the Argyll
Robertson phenomenon (normal pupil constriction
to a near target but reduced reaction to light) owing
to a midbrain defect. In Parinaud’s syndrome, the
pupils are typically large and poorly reactive to light,
with abnormal vertical gaze, convergence retraction
nystagmus and lid retraction on attempted upgaze
(Collier’s sign). The causes of light- near dissociation
are given in Box 21.2.
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Figure 21.3 Testing vision with a pinhole. Top: light is not
focused on the retina owing to refractive error (in this case in front
of the retina, as in myopia, or short- sightedness). Bottom: the use
of a pinhole selects rays of light not needing to be focused, giving
a better indication of a patient’s true best corrected visual acuity
despite refractive error.
Figure 21.4 Recording visual acuity: the numerator is the test
distance. ph, pinhole.
Pupil shape
Slit- lamp examination is the best technique to assess
intrinsic ocular disease that may affect the shape and
position of the pupil (Box 21.3).
Direct ophthalmoscopy
The direct ophthalmoscope is an indispensable
clinical instrument that allows direct visualization of
the retina, which is part of the central nervous system
(CNS), and its circulation. It consists of a bright,
focused light source that illuminates the retina to
allow the observer to see the image, magnified about
15 times.
Preparation
1. Decide the objective of the examination.
2. Consider dilating the pupils with 1%
cyclopentolate (Mydrilate) (0.5% in children
under 6 months) or 1% tropicamide (Mydriacyl).
This blurs the vision for at least 2 hours, so
patients should be forewarned and instructed
not to drive. Some patients have a predisposition
to closed- angle glaucoma (Box 21.4) and dilation
may precipitate an attack. At- risk individuals
must be warned to return if symptoms of acute
angle closure occur.
3. Briefly explain the examination so that the
patient can cooperate fully. Ask the patient to
fixate on a distant target: the patient should
continue to look in this direction even if the
examiner’s head obscures the target.
4. Dim the room lights.
5. Set the ophthalmoscope lens wheel to zero
dioptres (D), unless correcting for your own
short- or long- sightedness.
6. Ensure that the ophthalmoscope light is bright.
Unless the pupil is small, select a large light spot
size (Box 21.5, Fig. 21.8).
Examining the fundi
Look carefully at the optic disc/cup, the retinal
vessels and the retina and macula (Fig. 21.9).
Optic disc
The optic disc marks the point where the retinal
axons exit the back of the eye to form the optic
nerve. It corresponds to the physiological blind
spot. The normal disc is round or slightly oval. With
astigmatism, the disc may appear more oval than
normal. There are four key questions to consider
when viewing the optic disc:
1. Is the colour normal? The normal disc is
yellow- pink and its temporal side is paler. An
abnormally pale disc is a sign of optic atrophy
(Fig. 21.10). In addition, in optic atrophy there is
a reduction in the number of capillaries crossing
the edge of the disc, from the normal 10 to 7 or
fewer (Kestenbaum’s sign). The causes of optic
atrophy are listed in Box 21.6. In primary optic
atrophy owing to optic nerve lesions, the disc is
flat and white, with clear- cut edges. Secondary
optic atrophy follows swelling of the optic disc
owing to papilloedema: the disc is greyish- white,
with indistinct edges.
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Figure 21.5 Ishihara colour vision test.
Eyes
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Figure 21.6 Automated static perimetry: the Humphrey field test
analyser.
Box 21.1
Causes of anisocoria
Idiopathic (12% population)
Parasympathetic:
– Third nerve palsy (external ophthalmoplegia)
– Tonic pupil (internal ophthalmoplegia, e.g.
Holmes- Adie)
Sympathetic:
Horner’s syndrome
Argyll Robertson
Pharmacological
Ocular:
– Iris inflammation (e.g. iritis)
– Iris ischaemia
– Trauma
– Iatrogenic
Box 21.2
Light- near dissociation
Argyll Robertson pupil
Holmes- Adie pupil
Parinaud’s syndrome
Aberrant third nerve regeneration
Myotonic dystrophy
Diabetes mellitus
Figure 21.7 Horner’s syndrome. On the affected side there
is ptosis, which may be very slight, and a small pupil (miosis)
that reacts to both light and accommodation. (Reproduced with
permission from Mir, 2003 Atlas of Clinical Diagnosis, ed 2.
Saunders, Edinburgh.)
Box 21.3
Causes of abnormal pupil shape
Congenital: Rieger’s anomaly (anterior segment cleavage
anomalies)
Trauma
Iatrogenic (sphincterotomies, iridectomy, cataract
surgery)
Inflammatory (posterior synechiae in iritis)
Tumour (ectropion uveae in ciliary body malignancies)
Ischaemic: herpes zoster, angle- closure glaucoma
Idiopathic: iridocorneal endotheliopathy (ICE) syndrome
(which also features multiple pupils (polycoria) and
misplaced pupils (correctopia))
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Box 21.4
Risk factors for acute angle- closure glaucoma:
dilate pupils cautiously
Intermittent symptoms of angle- closure attack (see
symptoms in Table 21.2)
High hypermetropia
Old age
Narrow anterior chamber angles (detected on slit- lamp
gonioscopy)
Family history of acute angle- closure glaucoma
Box 21.5
Technique of ophthalmoscopy
Use your LEFT eye for the patient’s LEFT eye, holding the
ophthalmoscope with your LEFT hand and using your
RIGHT hand with your thumb over the LEFT brow to steady
the patient’s head (the opposite approach is used for the
right eye) (Fig. 20.8).
First, at arm’s length, look for and examine the red
reflex (like that in flash photographs). The red reflex is
dimmed in elderly people with cataracts, and these may
obscure the retina. In a child, congenital cataract and
retinoblastoma may abolish the red reflex.
Looking at the red reflex through the ophthalmoscope,
gradually close in on the eye to examine the anterior ocular
structures. Use the +20 D lens to view the cornea and the
+15 D lens for the iris. Some ophthalmoscopes have a lever
to switch to these lenses.
Then, with a zero lens setting, locate the optic disc. If it
is difficult to find, locate any blood vessel and follow it
towards the optic disc. Fine- tune the focus with 1–2 D
lens steps; if the focus worsens, reverse the other way.
If your eye is emmetropic and your accommodation is
relaxed, the strength of the lens necessary to bring the
fundus into focus indicates the refractive error of the
patient’s eye (plus or red lenses indicate hypermetropia
and minus or black lenses myopia).
Compare the two eyes. There is a broad range of
normal appearances, so if an unusual appearance is
symmetrical, it could be a variant of normal.
Figure 21.8 Examining the right eye with the direct
ophthalmoscope.
67
61
)
0
Figure 21.9 Normal fundus anatomy. OC, optic cup; OD, optic
disc. Retinal vascular arcades: F, fovea; IN, inferonasal; IT,
inferotemporal; M, macula; SN, superonasal; ST, superotemporal.
2&
2'
,1
,7
2. Are the margins distinct? The disc margin should
be sharply defined. In optic disc swelling, this
clear edge is obscured (Fig. 21.11) and venous
pulsations are abolished. However, venous
pulsations may be difficult to see in some
normal subjects. Some important causes of disc
swelling are listed in Box 21.7. In papilloedema,
caused by raised intracranial pressure, the disc
is abnormally red and its margins are blurred,
especially at the upper and lower margins, and
particularly in the upper nasal quadrant. The
physiological cup becomes obliterated and
the retinal veins are slightly distended. As the
condition progresses, the disc becomes more
definitely swollen (Fig. 21.12). In order to
measure the degree of swelling, start with a high
plus lens in the ophthalmoscope and reduce the
Figure 21.10 Primary optic atrophy. The disc is pale and whiter
than normal, and its edges are unusually sharply demarcated from
the retina. The retinal vessels are slightly attenuated.
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