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Paediatric cataract
Cataract in children often interferes with normal visual
development and is a significant cause of visual
handicap. Therefore, it is an important problem to pick
up and treat as early as possible.
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Cataract in childhood can be classified as
congenital, infantile and juvenile,
depending on the age of onset. Congenital
cataract is present at birth, but may not be
obvious and therefore can go unnoticed
until it is observed to have an effect on the
child’s visual function. Infantile cataract
refers to cataract which develops in the first
two years of life, and juvenile cataract has a
later onset (many lens opacities which are
classified as infantile or juvenile are, in
fact, congenital cataracts which were not
picked up at birth).
Childhood cataract can also be classified
according to aetiology, (i.e. traumatic
cataract, autosomal dominant cataract etc),
and morphology (i.e. lamellar cataract,
subcapsular, cortical etc).
The importance of making the diagnosis
and rapidly implementing treatment of
cataract in the young child cannot be overemphasised,
as it is the major preventable
cause of lifelong visual impairment. A
simple examination of the red reflex in the
newborn child allows this all too important
diagnosis to be made (Figure 1).
Aetiology
1. Hereditary cataract
Hereditary cataract is passed from one
generation to the next in autosomal
dominant fashion in 75% of cases of
congenital cataract 1 . The affected
individuals are usually perfectly well, and
have no associated systemic illness. Less
commonly, the inheritance may be
autosomal recessive 2 .
However, there are a number of rare
hereditary syndromes where the affected
individual not only has cataract, but also
has an associated systemic illness, for
example kidney and brain disease in Lowe’s
oculo-cerebro-renal syndrome, which is X-
linked recessive. It is, therefore, important
that all children with congenital cataract are
examined by a paediatrician to exclude any
underlying systemic disorder.
2. Metabolic cataract
Congenital, infantile or juvenile lens
opacities may have an underlying metabolic
cause, for example, galactosaemia 3 .
Galactosaemia is a metabolic disorder in
which the child’s body cannot metabolise
galactose, a major component of milk and
milk products. The baby will have vomitting
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Figure 1
Red reflex revealing a posterior subcapsular cataract after X
ray irradation of the eye
and diarrhoea, and develops typical ‘oil
droplet’ cataracts which are easily seen by
examining the red reflex. These are
reversible, and the lens returns to normal on
removing dairy products from the diet. If
this condition is not picked up and treated,
it leads to dense cataracts, deafness and
death.
Glucose-6-phosphate dehydrogenase
deficiency is an X- linked disorder and
therefore affects mainly males. These babies
present with jaundice and have haemolytic
anaemia, and may also develop infantile
cataract. Infection, acute illness and
ingestion of fava beans will precipitate an
attack of haemolysis (rupture of red blood
cells) in these children. Death may result,
unless the condition is diagnosed and
treated with an urgent blood transfusion.
Hypoglycaemia of whatever cause may
give rise to lens opacities in a child 4 . The
majority of babies with hypoglycaemia this
profound will also have convulsions and may
have permanent brain damage.
Hypocalcaemia may result in cataracts 5
(Figure 2), though these are usually
functionally less significant than cataracts
resulting from hypoglycaemia.
Mannosidosis is an autosomal recesively
inherited metabolic disease which can be
associated with infantile cataracts 6 . In this
disorder, the deficient enzyme is alpha
mannosidase, and these children also have
corneal clouding and optic atrophy. Other
features include deafness, skeletal dysplasia
and mental retardation which is variable.
3. Traumatic cataract
Trauma is the most common cause of
unilateral cataract in children. Traumatic
cataract is usually the result of a
penetrating injury, though blunt trauma can
also lead to cataract formation.
Figure 2
Lamellar cataract in a patient with a previous
episode of hypocalcaemia
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4. Secondary cataract
The most common type of secondary
cataract seen in the paediatric
ophthalmology clinic is as a result of uveitis
seen in conjunction with arthritis (juvenile
chronic arthritis (JCA)). The cataract may be
as a direct result of inflammation within the
anterior segment, or can also result from
the steroids used to treat the condition.
Cataracts caused by steroid ingestion are
usually posterior subcapsular. Progression of
the cataract will be halted following
cessation of treatment although not
reversible.
Less frequently, cataract may be seen
secondary to an intraocular tumour such as
retinoblastoma. Retinoblastoma is a
malignant tumour of the retina and can
spread to the brain resulting in death,
thus immediate referral and treatment is
vital.
5. Cataract secondary to maternal
infection during pregnancy
The most common maternal infection to
cause congenital cataract in the child is
rubella, more commonly known as German
measles. The cataracts caused by rubella
may be present at birth, or develop several
months later. These children may also have
microphthalmia, glaucoma, retinal
disease, microcephaly, deafness and heart
defects.
Other infectious diseases which may
have affected the mother during pregnancy,
such as toxoplasmosis (picked up from cat’s
faeces), toxocariasis (picked up from dog’s
faeces), and cytomegalovirus (CMV) can also
cause congenital cataracts along with
systemic illness in the newborn baby.
6. Iatrogenic cataract
Iatrogenic cataract is most commonly seen
in children who have had total body
irradiation 7 for leukaemia, and in children
who have had organ transplants and are on
long-term systemic steroid therapy 8 . These
children are usually older children and do
very well after cataract surgery.
7. Syndromes and congenital cataract
There are large variety of chromosomal and
dysmorphic syndromes, in which the child
will have a high risk of having congenital
cataract (Table 1). It is important to notice
any abnormal features in children presenting
with cataract, such as unusual facial
features, extra digits, unusual skin, short
stature, developmental delay, microcephaly
or hydrocephaly, as it is essential that the
child’s diagnosis is made so that any
necessary treatment is given to the child,
and so the parents can receive genetic
counselling about the possible risks of
producing other offspring with similar
problems.
Presentation
How do children with cataracts present?
Obviously, older children are able to tell
their parents and carers that they are
having visual difficulties. A very shy and
quiet child may not complain, but their
school-work may deteriorate and an
observant teacher may become suspicious
that the child is having visual difficulties.
However, all is not so straightforward
with the non-verbal infant or child. These
babies may present in different ways. For
example, the mother or other family member
may notice leukocoria (a white pupil). The
Table 1 Chromosomal and dysmorphic syndromes associated with congenital cataract
I. CONGENITAL CATARACT AND
DYSMORPHIC FACIAL FEATURES
II. CONGENITAL CATARACT AND
SHORT STATURE
III. CONGENITAL CATARACT
AND MICROCEPHALY
1. Trisomy 21 (Down’s syndrome)
2. Hallermann-Streiff-Francois syndrome
(characterised by certain facial features
such as a thin pointed nose, small
pointed chin, and can be associated
with breathing difficulties and in 15%
mental reardation)
3. Lowe’s oculo-cerebro-renal syndrome
(an X-linked recessive condition
characterised by chubby cheeks, renal
problems, congenital cataract and
glaucoma)
4. Nance-Horan syndrome (an X-linked
condition characterised by abnormal
dentition, prominent ears and congenital
cataract)
5. Smith-Lemli-Opitz syndrome (an
autosomal recessive condition in which
the children may have microcephaly,
cleft palate, congenital cataract and
overlapping fingers and toes)
6. Congenital cataract, microphthalmia,
septal heart defect and dysmorphic
facial features
IV. CONGENITAL CATARACT AND
DIGITAL ABNORMALITIES
1. Majewski syndrome (nornatal dawrfism,
extra fingers [polydactyly], cleft palate
2. Smith-Lemli-Opitz syndrome (see
above)
3. Schachat and Maumenee’s patient
(1982) - congenital cataract, mental
retardation; obesity; hypogenitalism;
skull deformities; polydactyly
1. Chondrodysplasia punctata (an
autosomal recessive condition
characterised by short limbs, abnormal
skin and typical skeletal features on x-
ray)
2. Autosomal recessive mental retardation,
cataract, ataxia, deafness and
polyneuropathy
3. Cataract, sensoryneural deafness;
hypergonadism; hypertrichosis; short
stature
4. Marinesco-Sjögren’s syndrome (an
autosomal recessive condition
characterised by unsteadiness of gait,
poor co-ordination, short stature and
mental retardation)
V. CONGENITAL CATARACT AND
DERMATOLOGICAL DISEASE
1. Conradi’s syndrome/Conradi-
Hunermann syndrome (short limbs, skin
changes [pitted skin] and skeletal
abnormalities)
2. Pollitt syndrome – (mental retardation,
brittle hair, short stature and skin
abnormalities)
3. Menke’s disease (an X-linked condition
characterised by severe mental
retardation, kinky hair, bone and
connective tissue abnormalities)
VI. CONGENITAL CATARACT WITH HYDROCEPHALUS OR SKULL DEFORMITIES
1. Autosomal cerebro-oculofacial skeletal
syndrome (COFS) (an autosomal
recessive syndrome characterised by
microcephaly, joint contractures, typical
facial features and failure to thrive)
2. Autosomal recessive congenital
infection-like syndrome (characterised
by microcephaly, seizures and
intracranial calcification)
3. Autosomal dominant microcephaly, eye
anomalies (congenital cataract and
coloboma), short stature and mental
retardation
4. Autosomal recessive congenital
cataract, mental retardation, motor,
sensory and autonomic neuropathy
5. Early onset Cockayne syndrome
(thought to be the same condition as
COFS)
6. Cri du Chat syndrome (5p deletion)
(microcephaly, mental retardation,
round face and high pitched cry in
infancy)
7. Autosomal recessive cataract,
microcephaly, renal tubular necrosis
and encephalopathy with epilepsy
8. Czeizal-Lowry syndrome (microcephaly,
hip disease and mental retardation)
9. Edwards syndrome (aniridia,
microcephaly, small jaw and
abnormalities of the nose)
1. HEC syndrome: hydrocephalus, endocardial fibroelastosis, cataract
2. Lerone; craniosynostsosis
3. Martsolf’s syndrome
4. Hydrocephalus and microphthalmia
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differential diagnosis of a leukocoria is
listed in Table 2. Suspicion may be aroused
if a baby startles every time someone picks
him/her up. In many cases, congenital
cataracts are spotted by the health visitor
at the six-week check.
Assessment
When a child presents with cataract, he/she
must have a full ophthalmic examination.
Visual acuity of each eye must be
checked, as this will be a major factor in
planning the management. In the verbal
child, the Snellen chart, Sheridan–Gardner
Singles and Kay Pictures are used to assess
acuity. In the non or pre-verbal child, visual
acuity is assessed using Cardiff Acuity Cards
or Forced Choice Preferential Looking (FPL).
It is important that the child’s ability to
fixate a light source or torch is not used as
an indicator of visual acuity, as a child with
total cataracts significantly affecting visual
acuity may fix and follow a light source
normally, despite being blind to non
luminous objects.
Strabismus must be checked for and any
co-existing amblyopia managed with
occclusion therapy.
Slit lamp examination performed (a
hand-held slit lamp is useful for examining
very small children), and the laterality and
density of the lens opacities assessed.
All children should have their intraocular
pressure checked in order to outrule coexisting
glaucoma. This is best done using
the hand-held air-puff tonometer.
Before dilating the pupils, an afferent
pupillary defect is excluded (there may be a
retinal or optic nerve lesion contributing to
visual loss and cataract formation).
Dilated fundoscopy is then performed to
ensure the retina and optic nerve is normal.
If the cataract is so dense that no fundal
details can be seen, B-scan ultrasonography
can be carried out following referral in order
to exclude a tumour or retinal detachment.
The child then has a full physical
examination by a paediatrician, and has
routine blood tests to test for congenital
infection, galactosaemia, hypocalcaemia and
hypoglycaemia. The urine is also checked for
aminoaciduria which may be present in
children with Lowe’s syndrome.
In specialised centres, a visual evoked
potential (VEP) is performed on very young
babies in whom a visual acuity cannot be
obtained, and in children with very dense
cataracts, and in whom a possible coexisting
visual pathway abnormality is
suspected. The VEP gives the clinician
information about the visual pathways, from
the ganglion cell layer in the retina to the
occipital cortex.
Management of
paediatric cataract
The management of cataract in the child
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Table 2 The differential diagnosis of leukocoria
Retinoblastoma - malignant retinal tumour
Cataract - lens opacity
Toxoplasmosis - infection of retina or optic nerve with toxoplasma
Toxocariasis - infection of retina or optic nerve with toxocara
Retinal dysplasia - hereditary retinal maldevelopment
Coats’ disease - congenital retinal telangiectasis and exudate
Retinopathy of prematurity - retinal disease seen in some neonates born at less than 32
weeks’ gestation
Persistent hyperplastic primary vitreous
Retinal astrocytoma - benign retinal tumour, can be associated with a systemic condition
known as tuberous sclerosis
High myopia with posterior staphyloma
Eales disease - retinal vasculitis with haemorrhages
Familial exudative vitreoretinopathy
Extensive myelinated nerve fibres
depends upon several factors: the child’s
age; the extent of visual loss; whether or
not there is an associated illness or coexisting
eye disease; and if the cataract
affects one or both eyes.
Surgery
Intraocular lens (IOL) implantation
is becoming an increasingly accepted
procedure in young children and infants.
Awareness of the rate of myopic shift which
takes place in the developing eye, and the
use of biometry helps to predict appropriate
IOL powers to try to ensure eventual
emmetropia. However, final refraction is
variable, such that emmetropia in adulthood
cannot be guaranteed, as there are
insufficient long-term studies. Whether or
not an IOL is inserted will depend on the
age of the child (recently in some centres
IOLs are inserted into the eyes of babies as
Table 3 The Great Ormond Street Occlusion Regime for Cataract
Occlusion regime for bilateral cataract
1. 0-1/2 octaves interocular difference
in visual acuity – no occlusion
2. 1-2 octaves interocular difference
in visual acuity – 1-2 hours of
occlusion of the better eye
3. More than 2 octaves interocular
difference in visual acuity – 2-4
hours occlusion of the better eye
4. If no improvement after stage 3 –
full-time occlusion
NB To be reviewed every 2 weeks
* i.e. a child aged 2 months is patched for 2 hours a day,
a 3 month old child for 3 hours/day etc.
** The difference between each Cardiff Card is one octave
young as four weeks of age), whether or
not there is any underlying ocular
pathology in which IOL implantation is
contra-indicated. In some instances, for
example, in remote areas in less
industrialised countries where it is unlikely
that the child will be able to be brought
back for regular follow-up, IOL implantation
is not advisable.
Bilateral cataracts
Surgery is indicated when the cataracts are
interfering with normal visual development.
If the vision is good, then surgery is not
indicated, and the child has regular checkups.
If there is a significant deterioration
in that child’s acuity at any stage, then
surgery is considered.
If a child has bilateral dense cataracts,
one eye is operated on followed by the
second eye one to two weeks later. The first
Occlusion regime for unilateral cataract
1. The phakic eye is occluded 1hour/day for
each month of life* until 6 months of age.
After 6 months occlusion depends on
interocular difference (see 2-4 below)
2. 0-1/2 octave interocular difference in visual
acuity – 50% of waking hours
3. 1-2 octaves interocular difference in visual
acuity – 75% of waking hours
4. More than 2 octaves interocular difference
in visual acuity – 100% waking hours
NB To be reviewed every 2 weeks
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eye is occluded post-operatively until the
second eye is operated on, to prevent
amblyopia in the un-operated eye. In very
young babies, an IOL is not inserted; these
babies are given contact lenses one to two
weeks post operatively, and if contact lens
are contra-indicated, the child is given
aphakic spectacles. In some of these
children, an IOL may be inserted as a
secondary procedure when the eye has
grown. In general, an IOL is inserted into the
eye of older babies, and depending on the
age of the child, an IOL power is selected
(according to the biometry) to make that eye
appropriately hypermetropic, and hence allow
for the myopic shift which takes place in the
developing eye; the aim is for emmetropia
when the eye is fully grown.
In the older child, for example a seven
year old child with bilateral cataracts which
are beginning to significantly interfere with
visual acuity, the eye with the worst visual
acuity is operated on, followed by the
second eye at least three to four weeks
later.
All surgery has potential complications,
and the parents are warned about all
possible complications pre-operatively (see
later). Complications of lens aspiration and
IOL implantation include post-operative
uveitis, endophthalmitis, glaucoma and
retinal detachment. In addition, there is a
greater than 90% risk that the posterior
capsule will become thickened within in a
year, which requires a further procedure
either with laser or surgical capsulotomy to
clear the visual axis and restore visual
acuity to what it was initially postoperatively.
In order to reduce the need for
repeated general anaesthetics in order to
perform laser and or surgery, a primary
posterior capsulorhexis (and limited anterior
vitrectomy) may be performed. This involves
making a hole in the posterior capsule and
removing a small amount of vitreous at the
time of the initial cataract surgery. This
procedure significantly reduces the
development of posterior capsular
opacification.
Unilateral cataract
In infants with unilateral cataract, the
cataract is most likely to be idiopathic and
there is usually no associated systemic
disease. It is important not to confuse
asymmetric bilateral cataract with unilateral
cataract and, hence, careful slit lamp
examination is essential in all children with
cataract, as there may be very subtle
changes in one lens and dense cataract in
the other.
With regard to the management of
unilateral cataract, the decision to operate
depends on the density of the lens opacity,
whether or not there is any associated
microphthalmos, and on the parent’s
motivation to have the surgery performed.
The parents need to be fully informed that
surgery alone will not improve their child’s
vision, and that the management of
amblyopia is the key to a successful result.
This entails optical correction and many
hours of patching the normal eye every day
(Table 3), which as one knows can be
extremely difficult in a small infant or
toddler, and needs to be maintained for
many years. If occlusion is not performed
the eye will remain densely amblyopic.
It has been reported extensively in the
literature that children who have had
surgery for bilateral cataracts have a much
better visual outcome than children who
have had surgery for unilateral cataract.
Children with unilateral cataract need
diligent occlusion therapy of the unoperated
eye together with accurate optical
correction of the operated eye to obtain a
good visual result.
Optical correction
post-operatively
Aphakia
If the child has not had an IOL inserted and
is therefore aphakic, contact lenses are
fitted as soon as possible after surgery,
regardless of age. This is usually done one
to two weeks post-operatively. The baby is
refracted and contact lenses fitted. Contact
lenses are relatively safe 9 , they can be used
in combination with spectacles for near, and
also to correct aniseikonia 10 . Rigid gas
permeable contact lenses are most suitable
for the management of aphakia, as they
have a wide range of powers, can correct
astigmatism, and are relatively cheap. The
disadvantages of contact lens wear are
similar to those seen in adults, and include
hypoxia and infective keratitis. Parents
should be educated about contact lens
hygiene and the signs and symptoms of
possible complications associated with
contact lens wear. All infants and
children wearing contact lenses should be
kept under constant review at a specialised
unit.
If contact lenses cannot be fitted (e.g.
raised intraocular pressure, external eye
disease, dry eye, severe microphthalmos or
parents who are unable to cope with
contacts), the child is given aphakic
spectacles which have the advantage of
increasing magnification and, therefore,
enhancing the child’s acuity, and in can
make the eyes of children with
microphthalmia look slightly bigger.
Pseudophakia
To allow for the future growth of the infant
eye (i.e the myopic shift) an IOL power less
than that to result in emmetropia is used.
This makes the child hypermetropic (the
amount of hypermetropia depends on the
age of the child), then as the child’s eye
grows emmetropia is approached. The child
is then given reading spectacles (and a
distance prescription if required).
Amblyopia management
post-operatively
The treatment of amblyopia is essential in
order to obtain a successful outcome in
patients who have had both unilateral and
bilateral cataract surgery. Amblyopia is
managed by giving the required optical
correction and occluding the eye with better
visual acuity. The occlusion is performed
according to a standardised regime 11
(Table 3). It is important to realise that
excessive patching of the phakic eye in
infants with unilateral aphakia may be
associated with increased nystagmus and
can have adverse effects on the phakic eye,
hence it is imperative that these children
are reviewed every two weeks.
Complications of
cataract surgery
Cataract surgery in the child and especially
in babies has a higher incidence of
complications than those seen after adult
cataract surgery. This may be due to several
reasons: cataract surgery is technically more
difficult in the child’s eye, as the tissues are
more elastic and behave differently to adult
tissues; the child’s eye becomes more
inflammed than an adult eye in response to
an IOL; the very young child’s visual system
is still developing and is therefore extremely
sensitive to having a defocused image as is
the case in aphakia; and a young child is
less likely to fully comprehend the
importance of keeping dirty fingers away
from the operated eye in the immediate
post-operative period and, therefore, may
rub the eye too vigorously resulting in
wound dehisence and iris prolapse or
infection.
There have been many reports of the
visual outcome and complications of
posterior chamber lens implantation in
children 12-20 . The most common
complications include:
1. Glaucoma
Glaucoma may arise in the first few weeks
post-operatively, and may present as a
watery eye with or without photophobia.
The child is usually irritated or just “not his
usual self”. Some children are asymptomatic,
hence the importance of regular review with
IOP checks post-operatively.
Glaucoma may also occur as a late
complication years later, and this type of
glaucoma can be asymptomatic, therefore all
children who have had cataract surgery
should be followed up for life.
2. Uveitis
All children will develop a certain degree of
uveitis post-cataract surgery. This is kept
30
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under control with frequent installation of
topical steroids, which are given to all
children routinely, and are eventually tailed
off and discontinued. However, some
children (approximately 30%) develop
inflammation with fibrin formation. This
accumulation of fibrin may result in
secondary membrane formation blocking the
visual axis if not recognised and treated
promptly.
3. Irregular pupil
An irregularly shaped pupil after cataract
surgery may be due to: a) a strand of
vitreous coming forwards from the vitreous
cavity to the anterior chamber; b) damage
to the iris during surgery; and c) iris
prolapse, which may be due to accidental
trauma to the eye post-operatively and
requires urgent attention, as if left
untreated that eye may become infected,
and even the other eye may be at a risk
from sympathetic ophthalmia.
4. Endophthalmitis
Bacterial infection of the eye is a
devastating complication which can occur in
up to 0.4% of eyes after cataract surgery. It
may occur early (i.e. within days to weeks)
or late (months to years) post-operatively
and presents with a sore painful red eye,
and/or reduced vision, and requires urgent
hospital admission and treatment.
5. Posterior capsule opacification
Posterior capsule opacification occurs in up
to 90% of paediatric eyes after lens
aspiration when the posterior capsule and
anterior vitreous face are left intact. These
children, having had a good visual result
initially, later present with blurred vision.
The thickened posterior capsule is seen
using the slit lamp, or simply by examining
the red reflex. These children are admitted
as a day case and a posterior capsulotomy is
performed. Older children can have laser
treatment without a general anaesthetic. In
some cases, the capsule thickens again and
may require surgery to clear the visual axis.
6. Retinal detachment
Retinal detachment may occur years after
cataract surgery, and present with reduced
vision which may be preceeded by flashes
and floaters.
Conclusion
Cataract in early childhood, if not picked up
early and managed appropriately, can have
devastating visual consequences. Treatment
may not always be surgical, and parents
need to be aware that those children who
do require surgery will also need optical
correction and, in many cases, many hours
of occlusion therapy for the treatment of
amblyopia. It is also essential to be aware
that there are many syndromes and systemic
disorders which may be associated with
congential cataract and that may have
implications for the child’s health.
Acknowledegemt
Figures 1 and 2 reproduced with kind
permission from Consultant
Ophthalmologist, Nicholas Phelps Brown.
References
1. Scott, M.H., Hejtmancik, J.F.,
Wozencraft, L.A. et al (1994)
“Autosomal dominant congenital
cataract. Intraocular phenotypic
variability”. Ophthalmology 101: 866-71.
2. Forsius, H., Arentz-Grastvedt, B. and
Eriksson, A.W. (1992) “Juvenile cataract
with autosomal recessive inheritance. A
study from the Aland Islands, Finland”.
Acta. Ophthalmol. 70: 26-32.
3. Stambolian, D. (1988) “Galactose and
cataract”. Surv. Ophthalmol. 32: 33-49.
4. Merin, S. and Crawford, J. (1971)
“Hypoglycaemia and infantile cataract”.
Arch. Ophthalmol. 86: 495-8.
5. Hochman, H.I. and Mejlszenkier, J.D.
(1977) “Cataracts and pseudotumour
ceribri in an infant with vitamin D
deficiency rickets”. J. Pediatr. 90: 252-4.
6. Letson, R.D. and Desnick, R.J. (1978)
“Punctate lenticular opacities in type II
mannosidosis”. Am. J. Ophthalmol. 85:
218-24.
7. Henk, J.M., Whitelocke, R.A.F.,
Warrington, A.P. et al (1993) “Radiation
dose to the lens and cataract
formation”. Int. J. Radiat. Oncol. Biol.
Phys. 25: 815-20.
8. Brocklebank, J.T., Harcourt, R.B.,
Meadow, S.R. (1982) “Corticosteroid
induced cataracts in idiopathic
nephrotic syndrome”. Arch. Dis. Child.
53: 30-4.
9. Amaya, L., Speedwell, L. and Taylor,
D.S.I. (1990) “Contact lenses for infant
aphakia”. Br. J. Ophthalmol. 74: 150-4.
10. Enoch, J.M. and Hamer, R.D. (1983)
“Image size correction of the unilateral
aphakic infant”. Ophthalmic Paediatr.
Genet. 2: 153-65.
11. Tayloe, D.S.I., The Doyne Lecture.
(1998) “Congenital cataract: the
history, the nature and the practice”.
Eye 12: 9-36.
12. Thouvenin, D., Lesueur, L. and Arne,
J.L. (1995) “Implantation
Intercapsulaire dans les cataractes de
l’Enfant. Etude de 87 cas et
comparaison a 88 cas sans
implantation”. J. Franc. Ophthalmol.
18: 678-687.
13. Knight-Nanan, D., O’Keefe, M. and
Bowell, R. (1994) “Outcome and
complications of intraocular lenses in
children with cataract”. J. Cat. Ref.
Surg. 22: 730-736.
14. Brady, K.M., Atkinson, C.S., Kilty, L.A.
and Hiles, D.A. (1995) “Cataract
surgery and intraocular lens
implantation in children”. Am. J.
Ophthalmol. 120: 1-9.
15. Sinskey, R.M., Stoppel, J.O. and Amin,
P. (1993) “Long-term results of
intraocular lens implantation in
pediatric patients”. J. Cat. Ref. Surg.
19: 405-408.
16. Zwaan, J., Mullaney, P.B., Awad, A., Al-
Mesfer, S. and Wheeler, D.T. (1998)
“Pediatric Intraocular lens
implantation: Surgical results and
complications in more than 300
patients”. Ophthalmology 105: 112-
119.
17. Gimbel, H.V., Basti, S., Ferensowicz, M.
and DeBroff, B.M. (1997) “Results of
bilateral cataract extraction with
posterior chamber intraocular lens
implantation in children”.
Ophthalmology 104: 1737-1743.
18. Crouch, E.R., Pressman, S.H. and
Crouch, E.R. (1995) “Posterior chamber
intraocular lenses: long term results in
pediatric cataract patients”. J. Pediatr.
Ophthalmol. Strabismus 32: 210-218.
19. Burke, J.P., Wilshaw, H.E. and Young,
J.D.H. (1989) “Intraocular lens
implants for uniocular cataracts in
children”. Br. J. Ophthalmol. 73: 860-
865.
20. Churchill, A.J., Noble, B.A., Etchells,
D.E. and George, N.J. (1995) “Factors
affecting visual outcome in children
following uniocular traumatic cataract”.
Eye 9: 285-291.
ABOUT THE AUTHOR
Lorraine Cassidy is Locum Consultant Ophthalmologist at Great Ormond Street Hospital for
Children, and at St Helliers and Sutton Hospitals, Surrey. She has a special interest in
paediatric ophthalmology and trained with David Taylor and Isabelle Russell-Eggitt at Great
Ormond Street.
www.optometry.co.uk 31

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Multiple choice questions
Paediatric cataract MCQs
1. Hypoglycaemia in an infant is most likely
to give rise to all of the following except:
a. cataract
b. convulsions
c. permanent brain damage
d. skeletal dysplasia
2. ‘Oil droplet’ cataracts are
associated with which disorder?
a. Galactosaemia
b. Mannosidosis
c. Trauma
d. Glucose-6-phosphate dehydrogenase
deficiency
3. Which one of the following statements
is incorrect regarding cataract?
a. Short stature may be associated with
cataract
b. Cataracts which result from the metabolic
abnormality known as galactosaemia can be
reversible
c. Congenital cataracts are most easily seen by
looking at the red reflex in the first week of
life
d. In babies with dense congenital cataract it
is best to wait until the child is at least five
years old before considering surgery
4. Which one of the following statements is
correct regarding cataract?
a. Contact lenses are contraindicated in
children under six weeks old
b. Leukocoria is always a benign ocular sign
which warrants routine referral
c. Steroid induced cataracts are reversible on
discontinuing steroid therapy
d. Microphthalmos may be a contra-indication
of contact lens wear
Please note there is only ONE correct answer
5. Steroid induced cataracts are typically:
a. lamellar
b. anterior polar
c. cortical
d. posterior subcapsular
6. Which one of the following
statements is correct?
a. Children who have had surgery for unilateral
cataract have a much better visual outcome
than children who have had surgery for
bilateral cataracts
b. When a very young infant is having
an IOL implanted, the power of the
IOL is calculated to make the child
myopic
c. Management of ambyopia is essential in
improving visual function
d. Bilateral cataracts are often operated in
simultaneously
7. Complications of cataract surgery in the
child include all of the following except:
a. glaucoma
b. uveitis
c. retinal detachment
d. diabetes
8. A child who presents with a watery
eye one or two weeks post cataract
surgery is most likely to have:
a. conjunctivitis
b. a blocked tear duct
c. glaucoma
d. posterior capsular opacification
9. Endophthalmitis occurs in what
proportion of eyes following
cataract removal?
a. 0.4%
b. 1%
c. 0.2%
d. 10%
10. Posterior capsular opacification occurs in
what proportion of eyes following
cataract removal?
a. 50%
b. 60%
c. 70%
d. 90%
11. According to the Great Ormond Street
Occlusion Regime for Cataract, a child
with bilateral cataract showing 1-2
octaves interocular difference in visual
acuity will be occluded for what period of
time?
a. One to two hours of the better eye
b. No occlusion
c. Two to four hours of the better eye
d. Full-time occlusion
12. According to the Great Ormond Street
Occlusion regime for cataract, a child
with a unilateral cataract showing more
than 2 octaves interocular difference in
visual acuity will be occluded for what
period of time?
a. 50% of waking hours
b. 1 hour/day for each month of life
c. 75% of waking hours
d. 100% of waking hours
An answer return form is included in this issue.
It should be completed and returned to:
CPD Initiatives (c2983d),
OT, Victoria House, 178–180 Fleet Road, Fleet,
Hampshire, GU13 8DA by April 4, 2001.
32
March 9, 2001 OT
www.optometry.co.uk

Sponsored by
Module 3 Part 3
Multiple choice answers - The epidemology of cataract
Here are the correct answers to CPD module 3 part 2, which appeared in our February 9 issue.
1. The UK government is aiming for how
many cataract operations per year in
its Action on Cataracts initiative?
a. 175,000
b. 250,000
c. 1,500,000
d. 30 million
b is the correct answer
The Department of Health, in its initiative
Action on Cataracts, aims to increase
cataract surgery from the current annual
estimate of 175,000 cases to 250,000
within three years, mostly by improving
efficiency. There are 1,500,000 cataract
surgeries a year in the United States, and
it is estimated that there are 38 million
people blind from cataract in the world.
2. Which one of the following
statements is correct?
a. Studies investigating cataract are easy to
compare
b. Cataract grading methods should not be
sensitive to change
c. Photographic grading systems are most
reproducible and reliable
d. Lens opacities usually regress in
epidemiological studies
c is the correct answer
There have been many different cataract
grading systems used, making comparison
of different studies difficult. In order to
detect change, cataract grading systems
must be sensitive to detect that change,
which is why many systems have been
decimalised from simple 0-5 grading
points, to 0.1, 0.2 etc, up to 5.0.
Photographic systems are most
reproducible and reliable as there is ‘hard
evidence’ to compare, compared to
subjective systems. Lens opacities do not
regress, and so studies with significant
regression suggest that the grading of
cataract was not reliable.
3. Which one of the following
statements is correct?
a. Genes are important in congenital cataract
b. The genes responsible for age-related
cataract have been identified
c. Environmental factors have been shown to
be more important than genetic make-up
d. Genes are unlikely to be important in agerelated
cataract
a is the correct answer
The Twin Eye Study has shown that genes
are important in age-related cataract, with
a heritability of 48%. Environment only
contributed to 14% of the variance,
although this may still be important in
individuals with particular genetic defects.
The gene mutations involved in agerelated
cataract are still unknown, but
many mutations have been identified in
congenital cataracts, which are often
familial.
4. The heritability of nuclear cataract
has been reported as:
a. 12%
b. 38%
c. 48%
d. 66%
c is the correct answer
The heritability of nuclear cataract in the
Twin Eye Study was 48%.
5. The prevalence of nuclear cataract:
a. is greater in women than men
b. is greater in men than women
c. is the same in the two sexes
d. is greatest in the 65-74 age group
a is the correct answer
The prevalence of nuclear cataract is greater
in women than men, as it is for cortical
cataract. The reasons for this are not
known. The prevalence of cataract is also
strongly age-related, so that cataract is
more common in those aged over 75 than
those aged 65-74 years.
6. In patients over the age of 75 years:
a. posterior subcapsular cataract is the
commonest cataract type
b. cortical cataract is present in over 40%
c. nuclear cataract is rare
d. diabetes is the commonest cause of lens
opacities
b is the correct answer
Cortical cataract is present in over 40% of
individuals over the age of 75 years, and
significant nuclear cataract in at least 50%.
www.optometry.co.uk 33

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Multiple choice answers - continued
Posterior subcapsular cataract is least
common, but is still present in over 10% of
those aged over 75. Although diabetes is a
risk factor for the development of cataract,
it is only present in around 2% of the
population and so is not the most important
cause of cataract in this age group.
7. Which one of the following has NOT
been shown to be associated with
cataract formation?
a. High myopia
b. Marfan’s syndrome
c. Myotonic dystrophy
d. Myasthenia gravis
d is the correct answer
Cataract has been associated with various
systemic conditions, such as connective
tissue disorders (myotonic dystrophy which
causes ‘Christmas tree’ cataracts) and
Marfan’s syndrome (also associated with lens
dislocation). It is also associated with
intraocular diseases such as uveitis, and
high myopia is a risk factor. Myasthenia
gravis, a myopathy causing fatiguable ptosis
and reduced eye movements, is not
associated with cataract itself. (However,
patients may require sustained oral
steroids for its treatment and may
develop cataracts as a result.)
8. Which one of the following is
associated with cortical
cataract?
a. Steroid intake
b. Smoking
c. Vitamin D
d. Ultraviolet light
d is the correct answer
Cortical cataract is associated with
increasing age, and is more common in
women and people of Afro Caribbean
descent. Ultraviolet light, in the form of
sunlight, has been assoiciated with cortical
cataract also. Smoking is not associated
with cortical cataract, and while steroids
may increase the risk of all types of
cataract, they are particularly associated
with posterior subcapsular cataract.
9. The London City Eye Study
demonstrated that:
a. alcohol may be related to cataract
b. ultraviolet light exposure is related to
posterior subcapsular cataract
c. smoking is associated with cataract
d. vitamin C is protective in cataract
c is the correct answer
The London City Eye Study suggested
smoking was associated with cataract, and
found a greater risk in smokers compared to
ex-smokers, and the ex-smokers carried a
greater risk than the non-smokers,
suggesting a causal link.
10. Which one of the following statements is
incorrect regarding cigarette smoking?
a. It is related to the development
of nuclear cataract
b. It is related to the development
of posterior subcapsular cataract
c. Ex-smokers have an increased risk of
developing cataract compared
to non-smokers
d. It is related to the development
of cortical cataract
d is the correct answer
Smoking has been particularly associated
with nuclear cataract, although some
studies have suggested it may also be
associated with posterior subcapsular
cataract. It has not been associated with
cortical cataract, however. As above, the
London City Eye Study did suggest that exsmokers
carried a greater risk than nonsmokers.
11. Hypertension may be related
to which type of cataract:
a. nuclear
b. cortical
c. posterior subcapsular
d. congenital
c is the correct answer
No consistent evidence has linked cataract
to hypertension, although the Beaver Dam
Eye Study did suggest that hypertensive
patients were slightly more likely to have
posterior subcapsular cataract than those
without hypertension.
12. Which one of the following statements
is correct regarding cataract?
a. 20 million people will be blind due to
cataract by 2020
b. Cataract is more common in men compared
to women
c. Tall height may be associated with cataract
d. Diarrhoea may be associated with cataract
d is the correct answer
Case-control studies have suggested that
severe diarrhoeal disease may be associated
with cataract in later life. Low height or
body weight may also be associated
with cataract, and may reflect early
malnutrition.
34
March 9, 2001 OT
www.optometry.co.uk