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& TRAINING<br />


Approved for: Optometrists 4<br />

Dispensing Opticians 4<br />

OT CET content supports Optometry Giving Sight<br />

Retinoscopy in infancy:<br />

cycloplegic versus non-cycloplegic<br />

C-18551 O/D<br />

Fabrizio Bonci, Dip. Optom (ITA), MCOptom<br />

Luigi Lupelli, Dip. Optom (ITA), FAILAC, FIACLE, FBCLA<br />

The assessment of refractive status in very young children is often not conducted<br />

in <strong>the</strong> same manner as for adult patients. In particular, <strong>the</strong> child’s age, <strong>the</strong>ir cooperation<br />

and dynamic refractive status will be key factors which influence <strong>the</strong><br />

accuracy of refraction. For this reason, it is often necessary to choose procedures<br />

which inhibit or minimise accommodative activity. This can be achieved by<br />

fogging with positive lenses or rousing <strong>the</strong> tonic (resting) accommodation<br />

(dry refraction), or with pharmacological agents (wet refraction). This review<br />

article compares <strong>the</strong> two approaches, focusing on <strong>the</strong> retinoscopy techniques.<br />

Dry retinoscopy<br />

Static retinoscopy<br />

The patient views a distance target (foursix<br />

metres) so that accommodation is<br />

presumed to be static and in a relaxed<br />

condition. The fixating eye (contralateral<br />

to <strong>the</strong> one being examined) should be<br />

adequately “fogged” with a positive lens<br />

(resulting in an “against” movement seen<br />

on <strong>the</strong> retinoscopy swipe). 1 For children,<br />

maintaining fixation at this distance<br />

can be difficult and new computerised<br />

test charts generally provide dynamic<br />

and more interesting targets to view<br />

than a standard spotlight (Figure 1)<br />

to help with this. It is also possible<br />

to download a number of videoclips,<br />

especially cartoons, with different<br />

animations. Practitioners should also<br />

consider not using a phoropter or trial<br />

frame when conducting retinoscopy<br />

on a very young child, as this can be<br />

intimidating for <strong>the</strong> child. It is preferable<br />

to use single trial lenses or a lens rack.<br />

Speed during retinoscopy is essential<br />

when performing this technique in<br />

young children, especially as <strong>the</strong>y<br />

maintain fixation only for very short<br />

periods of time. In cases of fluctuation of<br />

accommodation, <strong>the</strong> practitioner should<br />

follow <strong>the</strong> “with” movement, ignoring <strong>the</strong><br />

occasional “against” movements seen.<br />

Figure 1<br />

Examples of exciting targets presented by computerized test charts during retinoscopy. Different face<br />

expressions allow to <strong>the</strong> practitioner to talk to <strong>the</strong> child to maintain attention on <strong>the</strong> target (Courtesy of<br />

Thomson Software Solutions, UK).<br />

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Yeotikar et al. 2 evaluated <strong>the</strong> difference<br />

in refractive error in non-strabismic<br />

children between <strong>the</strong> ages of seven years<br />

and 16 years, using static retinoscopy<br />

under two conditions – first by fogging<br />

<strong>the</strong> contralateral eye with a positive<br />

lens and second with cycloplegia using<br />

cyclopentolate 1%. The study found<br />

that <strong>the</strong> average difference in refractive<br />

error between <strong>the</strong>se two conditions<br />

was only 0.29DS more hypermetropic<br />

with cyclopentolate, highlighting <strong>the</strong><br />

accurate results that can be obtained<br />

when <strong>the</strong>re is adequate accommodative<br />

control during static retinoscopy.<br />

Fur<strong>the</strong>rmore, Chan and Edward3 suggested a calculation which can be<br />

used to match <strong>the</strong> dry retinoscopy<br />

result to that which would be obtained<br />

using cyclopentolate 1%, in children<br />

between 3.5 to five years of age. The<br />

astigmatic component is kept <strong>the</strong> same<br />

whilst <strong>the</strong> spherical component found<br />

in both meridians is multiplied by 1.45<br />

and a value of 0.39D is added. However,<br />

this depends on an accurate static<br />

retinoscopy result having been obtained.<br />

Mohindra retinoscopy<br />

The Mohindra technique, also known<br />

as near retinoscopy or near monocular<br />

retinoscopy, carries <strong>the</strong> main advantage<br />

of being child-friendly and requiring less<br />

co-operation from <strong>the</strong> child. 4 In this case,<br />

<strong>the</strong> stimulus is <strong>the</strong> dimmed light source<br />

of <strong>the</strong> retinoscope in a darkened room.<br />

The darkness of <strong>the</strong> room will facilitate<br />

<strong>the</strong> child to keep <strong>the</strong>ir attention on <strong>the</strong><br />

retinoscope’s light. The retinoscope<br />

is held at a distance of 50cm (errors in<br />

distance are not clinically relevant),<br />

with hand-held trial lenses used to find<br />

<strong>the</strong> neutral point. The accommodation<br />

activity during <strong>the</strong> examination is small<br />

and <strong>the</strong> same in both eyes. It is important<br />

during <strong>the</strong> examination to keep <strong>the</strong> light<br />

of <strong>the</strong> retinoscope on <strong>the</strong> child’s pupil<br />

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& TRAINING<br />


Approved for: Optometrists 4 Dispensing Opticians 4<br />

(to see <strong>the</strong> retinal reflex) for only a short<br />

period of time so as not to stimulate<br />

accommodation; subsequently <strong>the</strong><br />

optometrist’s attention should be focused<br />

on <strong>the</strong> pupil, watching for maximum<br />

dilation (indicating no accommodation). 5<br />

The procedure should be carried out<br />

with one eye occluded, preferably by <strong>the</strong><br />

parent, while <strong>the</strong> o<strong>the</strong>r eye is evaluated.<br />

However, Wesson et al. 6 confirmed that<br />

<strong>the</strong>re is no substantial difference in <strong>the</strong><br />

result if binocular fixation is allowed<br />

(Figure 2); indeed this can be useful if <strong>the</strong><br />

infant is resistant and becomes agitated<br />

with occlusion. Several people advocate<br />

neutralisation of <strong>the</strong> two principal<br />

meridians of <strong>the</strong> eye separately, using<br />

loose spherical trial lenses. However,<br />

Saunders and Westall7 confirmed that<br />

<strong>the</strong> accuracy of <strong>the</strong> technique can<br />

be improved using a combination of<br />

spherical and cylindrical lenses instead.<br />

Once <strong>the</strong> retinoscopy result is obtained, <strong>the</strong><br />

refractive error was originally calculated<br />

by adding -1.25DS to <strong>the</strong> gross finding. 8,9<br />

Saunders and Westall7 have reported<br />

that <strong>the</strong> accuracy can be improved if<br />

-0.75DS is added instead, for children<br />

aged between 0-2 years, and -1.00DS<br />

added for those children over two years<br />

of age. They also affirmed that <strong>the</strong> result<br />

achieved by <strong>the</strong> Mohindra procedure in<br />

children between six months and four<br />

years of age is similar to wet retinoscopy<br />

(using cyclopentolate 1% – see later),<br />

with a difference of only 0.50DS. O<strong>the</strong>rs<br />

have reported similar results, 10 and<br />

certainly no differences greater than<br />

1.00DS, 11 whilst similar results were<br />

also obtained for children with Down’s<br />

syndrome12 and even in adults. 13<br />

The Mohindra technique is useful for<br />

practitioners in Europe who are not<br />

permitted to used cycloplegic agents, 14<br />

whilst <strong>the</strong>re are benefits for conducting<br />

frequent follow-up assessments without<br />

repeated use of cycloplegic agents. 15<br />

One must remember, however, that <strong>the</strong><br />

OT CET content supports Optometry Giving Sight<br />

Figure 2<br />

Mohindra retinoscopy. Hand-held trial lenses are<br />

placed in front of both eyes whilst <strong>the</strong> child fixates<br />

<strong>the</strong> retinoscope light. The procedure should be run<br />

in darkened room (<strong>the</strong> high level of room light in<br />

this image was for photographic purposes only).<br />

accuracy of results will naturally depend<br />

on <strong>the</strong> practitioner’s experience. 16<br />

Cycloplegic agents<br />

Control of accommodation in children<br />

of pre-school age is more commonly<br />

achieved by pharmacological means,<br />

using cycloplegic agents such as<br />

cyclopentolate and tropicamide; atropine<br />

can only be used by <strong>the</strong>rapeutically<br />

qualified practitioners. All of <strong>the</strong>se drugs<br />

are muscarinic receptor blockers, thus<br />

<strong>the</strong>y work by blocking <strong>the</strong> muscarinic<br />

receptors in <strong>the</strong> ciliary body, which<br />

in turn prevents accommodation.<br />

A mydriatic effect is concurrently<br />

achieved by inhibiting muscarinic<br />

stimulation of <strong>the</strong> iris sphincter muscle.<br />

An ideal cycloplegic would have no<br />

ocular and systemic adverse effects.<br />

Also, it should produce a rapid onset of<br />

cycloplegia, blocking accommodation<br />

completely for an adequate period<br />

of time, before swiftly restoring<br />

accommodative ability. 17 Several<br />

studies have reported both ocular<br />

and systemic side effects (especially<br />

using atropine) in those children who<br />

have had a cycloplegic refraction,<br />

in addition to expected mydriasis<br />

and cycloplegia, as detailed later. 18<br />

Drug selection and instillation<br />

Cycloplegia is an invasive technique<br />

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which can be uncomfortable, or even<br />

distressing, for <strong>the</strong> child. This is notably<br />

so because <strong>the</strong> acidic pH of <strong>the</strong> cycloplegic<br />

agent leads to stinging on instillation.<br />

Some practitioners advocate <strong>the</strong> use of a<br />

local anaes<strong>the</strong>tic prior to instillation of<br />

<strong>the</strong> cycloplegic agent; proxymetacaine<br />

0.5% is <strong>the</strong> drug of choice as it stings less<br />

than o<strong>the</strong>r topical anaes<strong>the</strong>tics. However,<br />

this is not always recommended due to<br />

<strong>the</strong> risks associated with an anaes<strong>the</strong>tised<br />

cornea. To facilitate <strong>the</strong> application<br />

of cycloplegics, cyclopentolate has<br />

been instilled in spray form onto <strong>the</strong><br />

eyelashes and <strong>the</strong> closed upper lid. 19<br />

Practitioners should also be conscious<br />

of <strong>the</strong>ir instillation technique, since<br />

different degrees of cycloplegia between<br />

<strong>the</strong> eyes can occur, especially if <strong>the</strong><br />

child does not keep <strong>the</strong>ir eyes open wide<br />

enough and/or if <strong>the</strong>re is significant postinstillation<br />

tearing (which is very likely).<br />

As such, practitioners can opt to instil<br />

<strong>the</strong> higher concentration of cycloplegic<br />

agent and/or instil fur<strong>the</strong>r drops if<br />

regular review (eg, periodic measurement<br />

of <strong>the</strong> amplitude of accommodation)<br />

reveals differing levels of cycloplegia.<br />

Differences in <strong>the</strong> main cycloplegic<br />

agents are summarised in Table 1. The<br />

optometrist should select an appropriate<br />

agent considering factors such as <strong>the</strong><br />

patient’s age and whe<strong>the</strong>r <strong>the</strong>y have<br />

dark, or light coloured, irides. Adequate<br />

cycloplegic effect could be achieved<br />

with tropicamide in a teenage patient<br />

suspected of having latent hypermetropia,<br />

for example, whereas cyclopentolate<br />

is likely to be required for an infant<br />

suspected of having an accommodative<br />

esotropia. Those with light coloured<br />

irides may exhibit an increased response<br />

to drugs as compared with darkly<br />

pigmented irides, and <strong>the</strong>refore a lower<br />

concentration/dose ought to be selected.<br />

Overdose of cycloplegic agent has to<br />

be avoided in children with Down’s<br />

syndrome or those affected by cerebral<br />

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palsy, trisomy 13 and 18, and o<strong>the</strong>r<br />

central nervous system (CNS) disorders.<br />

This is because toxicity increases in<br />

<strong>the</strong>se people, especially children, which<br />

causes stimulation of <strong>the</strong> medulla<br />

and <strong>the</strong> cerebral centres, leading to<br />

hallucinogenic effects similar to those<br />

caused by LSD drugs. 20,21 These reactions<br />

generally occur within 20-30 minutes<br />

after administration. 22 Tropicamide<br />

1% should be considered in <strong>the</strong>se<br />

children as opposed to cyclopentolate.<br />

Cyclopentolate<br />

Cyclopentolate 0.5% or 1.0% is<br />

commonly used by practitioners as<br />

<strong>the</strong> cycloplegic agent of choice for<br />

paediatric examinations. The cycloplegia<br />

achieved is not too deep, as compared<br />

with atropine, but it is quicker in<br />

onset, often achieved after 30 minutes<br />

from its administration. Recovery of<br />

accommodation is typically between six-<br />

12 hours after instillation whilst mydriasis<br />

resolves by 24 hours after instillation.<br />

Although full cycloplegia is achieved<br />

with atropine, <strong>the</strong> cycloplegic refractive<br />

results obtained with cyclopentolate<br />

are comparable in “normals”, 23 high<br />

hypermetropic children24,25 and also<br />

those children with strabismus. 26,27<br />

For children under <strong>the</strong> age of three<br />

months, it is advised that two drops of<br />

cyclopentolate 0.5% are used as opposed<br />

to 1%. 28 This is becasue drug absorption<br />

through <strong>the</strong> conjunctival epi<strong>the</strong>lium and<br />

skin is more rapid in infants compared<br />

to adults, 29,30 due to immature metabolic<br />

enzyme systems in neonates and young<br />

children, which may prolong <strong>the</strong> effects<br />

of <strong>the</strong> drug. 31,32 The main side effects<br />

of cyclopentolate include incoherent<br />

speech, hallucinations and disorientation,<br />

psychosis and visual disturbances. 33,34<br />

Tropicamide<br />

This is an anti-muscarinic drug with<br />

short-lasting effect on <strong>the</strong> pupil<br />

(mydriasis) and on accommodation<br />

(cycloplegia) at <strong>the</strong> 1% concentration.<br />

Although tropicamide is mostly used for<br />

mydriasis, to examine <strong>the</strong> optical media<br />

and <strong>the</strong> ocular fundus, several studies<br />

have suggested that this drug can be used<br />

for a cycloplegic effect. 35 In particular,<br />

it is a cycloplegic agent that can at least<br />

detect latent hypermetropia, for example<br />

in school children, teenagers and those<br />

in <strong>the</strong>ir early 20s, with o<strong>the</strong>rwise normal<br />

refractive status and/or with moderate<br />

hypermetropia, 36 as well as for children<br />

during <strong>the</strong> post-natal period. 37 In adult<br />

patients undergoing refractive surgery, a<br />

study showed no significant difference<br />

in cycloplegic refraction between<br />

tropicamide 1% and cyclopentolate<br />

1%. 38 In <strong>the</strong> same patients, however,<br />

<strong>the</strong> study showed that cyclopentolate<br />

was more effective than tropicamide<br />

in reducing accommodative amplitude<br />

in adult myopes (near-point testing).<br />

Atropine sulphate<br />

This is a natural alkaloid extracted<br />

from <strong>the</strong> deadly nightshade (Atropa<br />

belladonna) plant. Its administration<br />

is justified in children of pre-verbal<br />

age or when o<strong>the</strong>r cycloplegic agents<br />

fail to produce a satisfactory level of<br />

cycloplegia. Atropine is administrated<br />

three times a day during <strong>the</strong> three days<br />

before <strong>the</strong> eye examination. Associated<br />

mydriasis decreases in two weeks after<br />

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Mydriasis Cycloplegia<br />

Agent Concentration Max effect Recovery<br />

time<br />

Max<br />

effect<br />

Recovery<br />

time<br />

Atropine 0.5-3.0% 1-2 hours 7-12 days 60-180 min 6-12 days<br />

Cyclopentolate 0.5-2.0% 30-60 min. 1 days 25-75 min 6-12 hours<br />

Tropicamide 0.5-1.0% 20-40 min 6 hours 20-35 min 4-6 hours<br />

Homatropine 2.0-5.0% 40-60 min. 1-3 days 30-60 min 1-3 days<br />

Scopolamine 0.25% 20-30 min 3-7 days 30-60 min 3-7 days<br />

Table 1<br />

Cycloplegic and mydriatic effects amongst <strong>the</strong> main cycloplegic drugs used in optometric practice<br />

<strong>the</strong> refractive examination. This drug is an<br />

antagonist of <strong>the</strong> muscarinic acetylcholine<br />

receptors, thus it dampens mediation of<br />

<strong>the</strong> parasympa<strong>the</strong>tic nervous system. As<br />

a result, systemic absorption of atropine<br />

can lead to difficulties with swallowing<br />

food (opposed effects of <strong>the</strong> vagus nerve),<br />

inhibition of <strong>the</strong> salivary glands leading<br />

to a dry mouth, and reduction of sweating.<br />

Atropine can also increase firing of <strong>the</strong><br />

sino-atrial node (SA) and conduction<br />

through <strong>the</strong> atrio-ventricular node (AV)<br />

of <strong>the</strong> heart, leading to tachycardia. It<br />

also decreases bronchial secretions,<br />

which can make breathing difficult.<br />

O<strong>the</strong>r side effects that have been reported<br />

include dizziness, nausea and sensation<br />

of being unbalanced and allergic<br />

reactions of <strong>the</strong> eyelids and conjunctiva.<br />

Atropine is able to pass through <strong>the</strong><br />

blood-cerebral-barrier and alter <strong>the</strong> state<br />

of consciousness of <strong>the</strong> child. Therefore,<br />

in order to minimise <strong>the</strong> systemic<br />

absorption of atropine, <strong>the</strong> practitioner<br />

can gently press <strong>the</strong> punctum of both eyes<br />

and keep <strong>the</strong> patient’s head tilted back.<br />

A recent study39 compared <strong>the</strong><br />

cycloplegic efficacy of homatropine<br />

2% and atropine 1% in children<br />

between <strong>the</strong> ages of four and 10 years by<br />

retinoscopy and automated refraction.<br />

As expected, <strong>the</strong> study reported that<br />

homatropine produced a significantly<br />

lesser cycloplegic effect than atropine,<br />

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& TRAINING<br />


Approved for: Optometrists 4 Dispensing Opticians 4<br />

with residual accommodation being<br />

greater (1.80±0.40D with atropine<br />

vs. 3.10±0.50D with homatropine;<br />


those with risk factors for binocular<br />

vision anomalies <strong>the</strong> refraction should<br />

be performed under cycloplegia.<br />

Tropicamide seems to be as effective<br />

as cyclopentolate for measurement of<br />

refractive error in most non-strabismic<br />

infants, particularly at <strong>the</strong> 1%<br />

concentration, so it should be considered<br />

more often in paediatric eye care in<br />

order to reduce <strong>the</strong> possibility of adverse<br />

Module questions Course code: C-18551 O/D<br />

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<br />

exams after this date. Answers to <strong>the</strong> module will be published on www.optometry.co.uk/cet/exam-archive. CET points for <strong>the</strong>se exams will be uploaded to Vantage<br />

on May 14, 2012. Find out when CET points will be uploaded to Vantage at www.optometry.co.uk/cet/vantage-dates<br />

1. Which of <strong>the</strong> following statements is TRUE?<br />

a) Atropine produces cycloplegia within 2-3 hours and recovery of<br />

accommodation in 2 days<br />

b) Cyclopentolate produces cycloplegia within 30 minutes and<br />

recovery of accommodation in 12 hours<br />

c) Homatropine produces cycloplegia in 20-30 minutes and recovery of<br />

accommodation in 24 hours<br />

d) All of <strong>the</strong> above<br />

2. Which pharmacological agent should be considered in a child<br />

with Down’s Syndrome?<br />

a) Atropine<br />

b) Homatropine<br />

c) Cyclpentolate<br />

d) Tropicamide<br />

3. When should Mohindra’s retinoscopy technique be<br />

performed?<br />

a) In all children<br />

b) Only in children aged 7-10 years<br />

c) Only in young children with moderate astigmatism<br />

d) In pre-verbal children<br />

reactions. Where <strong>the</strong>re is suspicion of a<br />

binocular vision anomaly, cyclopentolate<br />

should be <strong>the</strong> agent of choice.<br />

About <strong>the</strong> authors<br />

Fabrizio Bonci is an optometrist and<br />

clinical research fellow at <strong>the</strong> division<br />

of clinical neuroscience and mental<br />

health, Imperial College, London, and<br />

<strong>the</strong> Faculty of Medicine, Charing Cross<br />

4. How should Mohindra’s retinoscopy technique be performed?<br />

a) In darkness, fixation being on <strong>the</strong> retinoscope light, using hand held lenses<br />

b) In room lighting, fixation being on a high contrast target at <strong>the</strong> retinoscope mirror<br />

c) In darkness, fixation being on a spotlight at 6 metres, using hand held lenses<br />

d) In room light, fixation being on a high contrast target at 6 metres, under<br />

cycloplegia<br />

5. Which of <strong>the</strong> following statements regarding cycloplegic refraction is<br />

TRUE?<br />

a) It should be considered in children with high hypermetropia or strabismus<br />

b) It should be considered in every child at every sight test<br />

c) Atropine is <strong>the</strong> cycloplegic of choice for a 5-year-old child<br />

d) Objective automated refraction should be used for prescribing decisions<br />

6. Which of <strong>the</strong> following is NOT a side effect of cyclopentolate?<br />

a) Incoherent speech<br />

b) Hallucinations<br />

c) Mydriasis<br />

d) Conjunctival hyperaemia<br />

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Hospital, London. Luigi Lupelli is an<br />

optometrist, professor in contact lenses<br />

at <strong>the</strong> Faculty of Science, Department<br />

of Physics, (Optics and Optometry)<br />

at <strong>the</strong> University of Roma Tre, Italy.<br />

References<br />

See www.optometry.co.uk/<br />

clinical. Click on <strong>the</strong> article title and<br />

<strong>the</strong>n on ‘references’ to download.<br />

53<br />

06/04/12 CET

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