Download the PDF

CET CONTINUING
EDUCATION
& TRAINING
1 FREE CET POINT
Approved for: Optometrists 4
Dispensing Opticians 4
OT CET content supports Optometry Giving Sight
Retinoscopy in infancy:
cycloplegic versus non-cycloplegic
C-18551 O/D
Fabrizio Bonci, Dip. Optom (ITA), MCOptom
Luigi Lupelli, Dip. Optom (ITA), FAILAC, FIACLE, FBCLA
The assessment of refractive status in very young children is often not conducted
in the same manner as for adult patients. In particular, the child’s age, their cooperation
and dynamic refractive status will be key factors which influence the
accuracy of refraction. For this reason, it is often necessary to choose procedures
which inhibit or minimise accommodative activity. This can be achieved by
fogging with positive lenses or rousing the tonic (resting) accommodation
(dry refraction), or with pharmacological agents (wet refraction). This review
article compares the two approaches, focusing on the retinoscopy techniques.
Dry retinoscopy
Static retinoscopy
The patient views a distance target (foursix
metres) so that accommodation is
presumed to be static and in a relaxed
condition. The fixating eye (contralateral
to the one being examined) should be
adequately “fogged” with a positive lens
(resulting in an “against” movement seen
on the retinoscopy swipe). 1 For children,
maintaining fixation at this distance
can be difficult and new computerised
test charts generally provide dynamic
and more interesting targets to view
than a standard spotlight (Figure 1)
to help with this. It is also possible
to download a number of videoclips,
especially cartoons, with different
animations. Practitioners should also
consider not using a phoropter or trial
frame when conducting retinoscopy
on a very young child, as this can be
intimidating for the child. It is preferable
to use single trial lenses or a lens rack.
Speed during retinoscopy is essential
when performing this technique in
young children, especially as they
maintain fixation only for very short
periods of time. In cases of fluctuation of
accommodation, the practitioner should
follow the “with” movement, ignoring the
occasional “against” movements seen.
Figure 1
Examples of exciting targets presented by computerized test charts during retinoscopy. Different face
expressions allow to the practitioner to talk to the child to maintain attention on the target (Courtesy of
Thomson Software Solutions, UK).
For the latest CET visit www.optometry.co.uk/cet
Having trouble signing in to take an exam?
View CET FAQ Go to www.optometry.co.uk
Yeotikar et al. 2 evaluated the difference
in refractive error in non-strabismic
children between the ages of seven years
and 16 years, using static retinoscopy
under two conditions – first by fogging
the contralateral eye with a positive
lens and second with cycloplegia using
cyclopentolate 1%. The study found
that the average difference in refractive
error between these two conditions
was only 0.29DS more hypermetropic
with cyclopentolate, highlighting the
accurate results that can be obtained
when there is adequate accommodative
control during static retinoscopy.
Furthermore, Chan and Edward3 suggested a calculation which can be
used to match the dry retinoscopy
result to that which would be obtained
using cyclopentolate 1%, in children
between 3.5 to five years of age. The
astigmatic component is kept the same
whilst the spherical component found
in both meridians is multiplied by 1.45
and a value of 0.39D is added. However,
this depends on an accurate static
retinoscopy result having been obtained.
Mohindra retinoscopy
The Mohindra technique, also known
as near retinoscopy or near monocular
retinoscopy, carries the main advantage
of being child-friendly and requiring less
co-operation from the child. 4 In this case,
the stimulus is the dimmed light source
of the retinoscope in a darkened room.
The darkness of the room will facilitate
the child to keep their attention on the
retinoscope’s light. The retinoscope
is held at a distance of 50cm (errors in
distance are not clinically relevant),
with hand-held trial lenses used to find
the neutral point. The accommodation
activity during the examination is small
and the same in both eyes. It is important
during the examination to keep the light
of the retinoscope on the child’s pupil
49
06/04/12 CET

50
06/04/12 CET
CET CONTINUING
EDUCATION
& TRAINING
1 FREE CET POINT
Approved for: Optometrists 4 Dispensing Opticians 4
(to see the retinal reflex) for only a short
period of time so as not to stimulate
accommodation; subsequently the
optometrist’s attention should be focused
on the pupil, watching for maximum
dilation (indicating no accommodation). 5
The procedure should be carried out
with one eye occluded, preferably by the
parent, while the other eye is evaluated.
However, Wesson et al. 6 confirmed that
there is no substantial difference in the
result if binocular fixation is allowed
(Figure 2); indeed this can be useful if the
infant is resistant and becomes agitated
with occlusion. Several people advocate
neutralisation of the two principal
meridians of the eye separately, using
loose spherical trial lenses. However,
Saunders and Westall7 confirmed that
the accuracy of the technique can
be improved using a combination of
spherical and cylindrical lenses instead.
Once the retinoscopy result is obtained, the
refractive error was originally calculated
by adding -1.25DS to the gross finding. 8,9
Saunders and Westall7 have reported
that the accuracy can be improved if
-0.75DS is added instead, for children
aged between 0-2 years, and -1.00DS
added for those children over two years
of age. They also affirmed that the result
achieved by the Mohindra procedure in
children between six months and four
years of age is similar to wet retinoscopy
(using cyclopentolate 1% – see later),
with a difference of only 0.50DS. Others
have reported similar results, 10 and
certainly no differences greater than
1.00DS, 11 whilst similar results were
also obtained for children with Down’s
syndrome12 and even in adults. 13
The Mohindra technique is useful for
practitioners in Europe who are not
permitted to used cycloplegic agents, 14
whilst there are benefits for conducting
frequent follow-up assessments without
repeated use of cycloplegic agents. 15
One must remember, however, that the
OT CET content supports Optometry Giving Sight
Figure 2
Mohindra retinoscopy. Hand-held trial lenses are
placed in front of both eyes whilst the child fixates
the retinoscope light. The procedure should be run
in darkened room (the high level of room light in
this image was for photographic purposes only).
accuracy of results will naturally depend
on the practitioner’s experience. 16
Cycloplegic agents
Control of accommodation in children
of pre-school age is more commonly
achieved by pharmacological means,
using cycloplegic agents such as
cyclopentolate and tropicamide; atropine
can only be used by therapeutically
qualified practitioners. All of these drugs
are muscarinic receptor blockers, thus
they work by blocking the muscarinic
receptors in the ciliary body, which
in turn prevents accommodation.
A mydriatic effect is concurrently
achieved by inhibiting muscarinic
stimulation of the iris sphincter muscle.
An ideal cycloplegic would have no
ocular and systemic adverse effects.
Also, it should produce a rapid onset of
cycloplegia, blocking accommodation
completely for an adequate period
of time, before swiftly restoring
accommodative ability. 17 Several
studies have reported both ocular
and systemic side effects (especially
using atropine) in those children who
have had a cycloplegic refraction,
in addition to expected mydriasis
and cycloplegia, as detailed later. 18
Drug selection and instillation
Cycloplegia is an invasive technique
Having trouble signing in to take an exam?
View CET FAQ Go to www.optometry.co.uk
which can be uncomfortable, or even
distressing, for the child. This is notably
so because the acidic pH of the cycloplegic
agent leads to stinging on instillation.
Some practitioners advocate the use of a
local anaesthetic prior to instillation of
the cycloplegic agent; proxymetacaine
0.5% is the drug of choice as it stings less
than other topical anaesthetics. However,
this is not always recommended due to
the risks associated with an anaesthetised
cornea. To facilitate the application
of cycloplegics, cyclopentolate has
been instilled in spray form onto the
eyelashes and the closed upper lid. 19
Practitioners should also be conscious
of their instillation technique, since
different degrees of cycloplegia between
the eyes can occur, especially if the
child does not keep their eyes open wide
enough and/or if there is significant postinstillation
tearing (which is very likely).
As such, practitioners can opt to instil
the higher concentration of cycloplegic
agent and/or instil further drops if
regular review (eg, periodic measurement
of the amplitude of accommodation)
reveals differing levels of cycloplegia.
Differences in the main cycloplegic
agents are summarised in Table 1. The
optometrist should select an appropriate
agent considering factors such as the
patient’s age and whether they have
dark, or light coloured, irides. Adequate
cycloplegic effect could be achieved
with tropicamide in a teenage patient
suspected of having latent hypermetropia,
for example, whereas cyclopentolate
is likely to be required for an infant
suspected of having an accommodative
esotropia. Those with light coloured
irides may exhibit an increased response
to drugs as compared with darkly
pigmented irides, and therefore a lower
concentration/dose ought to be selected.
Overdose of cycloplegic agent has to
be avoided in children with Down’s
syndrome or those affected by cerebral
Find out when CET points will be uploaded to Vantage at www.optometry.co.uk/cet/vantage-dates

palsy, trisomy 13 and 18, and other
central nervous system (CNS) disorders.
This is because toxicity increases in
these people, especially children, which
causes stimulation of the medulla
and the cerebral centres, leading to
hallucinogenic effects similar to those
caused by LSD drugs. 20,21 These reactions
generally occur within 20-30 minutes
after administration. 22 Tropicamide
1% should be considered in these
children as opposed to cyclopentolate.
Cyclopentolate
Cyclopentolate 0.5% or 1.0% is
commonly used by practitioners as
the cycloplegic agent of choice for
paediatric examinations. The cycloplegia
achieved is not too deep, as compared
with atropine, but it is quicker in
onset, often achieved after 30 minutes
from its administration. Recovery of
accommodation is typically between six-
12 hours after instillation whilst mydriasis
resolves by 24 hours after instillation.
Although full cycloplegia is achieved
with atropine, the cycloplegic refractive
results obtained with cyclopentolate
are comparable in “normals”, 23 high
hypermetropic children24,25 and also
those children with strabismus. 26,27
For children under the age of three
months, it is advised that two drops of
cyclopentolate 0.5% are used as opposed
to 1%. 28 This is becasue drug absorption
through the conjunctival epithelium and
skin is more rapid in infants compared
to adults, 29,30 due to immature metabolic
enzyme systems in neonates and young
children, which may prolong the effects
of the drug. 31,32 The main side effects
of cyclopentolate include incoherent
speech, hallucinations and disorientation,
psychosis and visual disturbances. 33,34
Tropicamide
This is an anti-muscarinic drug with
short-lasting effect on the pupil
(mydriasis) and on accommodation
(cycloplegia) at the 1% concentration.
Although tropicamide is mostly used for
mydriasis, to examine the optical media
and the ocular fundus, several studies
have suggested that this drug can be used
for a cycloplegic effect. 35 In particular,
it is a cycloplegic agent that can at least
detect latent hypermetropia, for example
in school children, teenagers and those
in their early 20s, with otherwise normal
refractive status and/or with moderate
hypermetropia, 36 as well as for children
during the post-natal period. 37 In adult
patients undergoing refractive surgery, a
study showed no significant difference
in cycloplegic refraction between
tropicamide 1% and cyclopentolate
1%. 38 In the same patients, however,
the study showed that cyclopentolate
was more effective than tropicamide
in reducing accommodative amplitude
in adult myopes (near-point testing).
Atropine sulphate
This is a natural alkaloid extracted
from the deadly nightshade (Atropa
belladonna) plant. Its administration
is justified in children of pre-verbal
age or when other cycloplegic agents
fail to produce a satisfactory level of
cycloplegia. Atropine is administrated
three times a day during the three days
before the eye examination. Associated
mydriasis decreases in two weeks after
For the latest CET visit www.optometry.co.uk/cet
Mydriasis Cycloplegia
Agent Concentration Max effect Recovery
time
Max
effect
Recovery
time
Atropine 0.5-3.0% 1-2 hours 7-12 days 60-180 min 6-12 days
Cyclopentolate 0.5-2.0% 30-60 min. 1 days 25-75 min 6-12 hours
Tropicamide 0.5-1.0% 20-40 min 6 hours 20-35 min 4-6 hours
Homatropine 2.0-5.0% 40-60 min. 1-3 days 30-60 min 1-3 days
Scopolamine 0.25% 20-30 min 3-7 days 30-60 min 3-7 days
Table 1
Cycloplegic and mydriatic effects amongst the main cycloplegic drugs used in optometric practice
the refractive examination. This drug is an
antagonist of the muscarinic acetylcholine
receptors, thus it dampens mediation of
the parasympathetic nervous system. As
a result, systemic absorption of atropine
can lead to difficulties with swallowing
food (opposed effects of the vagus nerve),
inhibition of the salivary glands leading
to a dry mouth, and reduction of sweating.
Atropine can also increase firing of the
sino-atrial node (SA) and conduction
through the atrio-ventricular node (AV)
of the heart, leading to tachycardia. It
also decreases bronchial secretions,
which can make breathing difficult.
Other side effects that have been reported
include dizziness, nausea and sensation
of being unbalanced and allergic
reactions of the eyelids and conjunctiva.
Atropine is able to pass through the
blood-cerebral-barrier and alter the state
of consciousness of the child. Therefore,
in order to minimise the systemic
absorption of atropine, the practitioner
can gently press the punctum of both eyes
and keep the patient’s head tilted back.
A recent study39 compared the
cycloplegic efficacy of homatropine
2% and atropine 1% in children
between the ages of four and 10 years by
retinoscopy and automated refraction.
As expected, the study reported that
homatropine produced a significantly
lesser cycloplegic effect than atropine,
51
06/04/12 CET

52
06/04/12 CET
CET CONTINUING
EDUCATION
& TRAINING
1 FREE CET POINT
Approved for: Optometrists 4 Dispensing Opticians 4
with residual accommodation being
greater (1.80±0.40D with atropine
vs. 3.10±0.50D with homatropine;
p

those with risk factors for binocular
vision anomalies the refraction should
be performed under cycloplegia.
Tropicamide seems to be as effective
as cyclopentolate for measurement of
refractive error in most non-strabismic
infants, particularly at the 1%
concentration, so it should be considered
more often in paediatric eye care in
order to reduce the possibility of adverse
Module questions Course code: C-18551 O/D
PLEASE NOTE There is only one correct answer. All CET is now FREE. Enter online. Please complete online by midnight on May 4, 2012 – You will be unable to submit
exams after this date. Answers to the module will be published on www.optometry.co.uk/cet/exam-archive. CET points for these exams will be uploaded to Vantage
on May 14, 2012. Find out when CET points will be uploaded to Vantage at www.optometry.co.uk/cet/vantage-dates
1. Which of the following statements is TRUE?
a) Atropine produces cycloplegia within 2-3 hours and recovery of
accommodation in 2 days
b) Cyclopentolate produces cycloplegia within 30 minutes and
recovery of accommodation in 12 hours
c) Homatropine produces cycloplegia in 20-30 minutes and recovery of
accommodation in 24 hours
d) All of the above
2. Which pharmacological agent should be considered in a child
with Down’s Syndrome?
a) Atropine
b) Homatropine
c) Cyclpentolate
d) Tropicamide
3. When should Mohindra’s retinoscopy technique be
performed?
a) In all children
b) Only in children aged 7-10 years
c) Only in young children with moderate astigmatism
d) In pre-verbal children
reactions. Where there is suspicion of a
binocular vision anomaly, cyclopentolate
should be the agent of choice.
About the authors
Fabrizio Bonci is an optometrist and
clinical research fellow at the division
of clinical neuroscience and mental
health, Imperial College, London, and
the Faculty of Medicine, Charing Cross
4. How should Mohindra’s retinoscopy technique be performed?
a) In darkness, fixation being on the retinoscope light, using hand held lenses
b) In room lighting, fixation being on a high contrast target at the retinoscope mirror
c) In darkness, fixation being on a spotlight at 6 metres, using hand held lenses
d) In room light, fixation being on a high contrast target at 6 metres, under
cycloplegia
5. Which of the following statements regarding cycloplegic refraction is
TRUE?
a) It should be considered in children with high hypermetropia or strabismus
b) It should be considered in every child at every sight test
c) Atropine is the cycloplegic of choice for a 5-year-old child
d) Objective automated refraction should be used for prescribing decisions
6. Which of the following is NOT a side effect of cyclopentolate?
a) Incoherent speech
b) Hallucinations
c) Mydriasis
d) Conjunctival hyperaemia
For the latest CET visit www.optometry.co.uk/cet
Hospital, London. Luigi Lupelli is an
optometrist, professor in contact lenses
at the Faculty of Science, Department
of Physics, (Optics and Optometry)
at the University of Roma Tre, Italy.
References
See www.optometry.co.uk/
clinical. Click on the article title and
then on ‘references’ to download.
53
06/04/12 CET