Cyloplegia and mydriasis

Question 1

what is cycloplegia

Answer 1

the paralysis of the cillary muscle resulting in a loss of accomoodattion

Question 2

what is the cillary body innervated by

Answer 2

cillary body is innervated by the parasympathetic nervous system

cycloplegia agents stop this innervation by competing with the acetylcholine receptor sites on the post synaptic membrane of the cillary muscle

Question 3

how is accomodation inhibited by cloplegics

Answer 3

although the drugs occupy the post synaptic receptor sites they don’t initiate the depolarisation of the neurone , by occupying these sites each is rendered ineffective temporarily

the nerve impulse which was started in the endanger Westphalia nuclei travelled via the cranial nerves does not activate the cillary muscle

this results in the temporal paralysis of accomodation

Question 4

what drug types are clycloplegics

Answer 4

All cycloplegics are anti-muscarinic,
anticholinergics,
cholinergic antagonists,
muscarinic antagonists,
muscarinic inhibitors,
parasympatholytics.
Note these synonyms!

Question 5

how should atropine 1% be used

Answer 5

Typically single-dose preparations (Minims) but can be as multi-use bottle (with preservative). Prescription Only Medicine (POM)
3 months to 17 years

Cautions:
Pigmented irides.
Narrow angles.
Neonates.

Question 6

what interactions should you be aware of when using atropine

Answer 6

Typically other drugs which have antimuscarinic effects but also levodopa (used in Parkinson’s disease) as cyclopentolate can reduce the absorption of levodopa.
Phenylephrine; atropine increases the risk of severe hypertension.

Question 7

what are the side effects of atropine

Answer 7

Photophobia, stinging.
confusion
constipation
dizziness
drowsiness
dry mouth
dyspepsia

flushing
headache
nausea
palpitations
skin reactions
tachycardia
urinary disorders
vision disorders
vomiting

Question 8

how should cycloplentate 0.5% and 1% be used

Answer 8

flushing
headache
nausea
palpitations
skin reactions
tachycardia
urinary disorders
vision disorders
vomiting

Question 9

what drug interactions should you be aware of with cyclopentalate

Answer 9

flushing
headache
nausea
palpitations
skin reactions
tachycardia
urinary disorders
vision disorders
vomiting

Question 10

what are the side effects of cyclopentalate

Answer 10

Abdominal distension
arrhythmias
behaviour abnormal
cardio-respiratory distress
conjunctivitis (on prolonged administration)
constipation
dry mouth
eye oedema (on prolonged administration)

flushing
gastrointestinal disorders
hyperaemia (on prolonged administration
palpitations
psychotic disorder
staggering
urinary disorders
vomiting

Question 11

how should tropicimacide be used 0.5% and 1%

Answer 11

As Minims or multi-use (Mydriacyl).
For cycloplegia in older children or teens one drop 1% followed by another drop five minutes later. POM
Cautions.
Pigmented irides. Narrow angles. Neonates.

Question 12

what drug interactions should you be careful of with tropiciamidie

Answer 12

Typically other drugs which have antimuscarinic effects but also levodopa (used in Parkinson’s disease) as cyclopentolate can reduce the absorption of levodopa.
Clozapine; risk of developing intestinal obstruction. Manufacturer advises caution.

Question 13

what are the side effects of tropiciamide

Answer 13

Eye erythema
eye irritation (on prolonged administration)
eye pain; headache
hypotension
nausea
syncope
vision blurred
(From BNFC 12-9-2022)

Question 14

what are the clinical uses of tropcimide

Answer 14

Paediatric refraction

Amblyopia therapy

Uveitis

Alleviation of ciliary spasm

Question 15

what is paediatric refraction necessary for

Answer 15

Essential for any practitioner to know the true refractive state in all presentations of paediatric strabismus, particularly esotropia. (Fotedar et al 2007)
The gold standard was atropine (and still gives the greatest depth of cycloplegia) but today Cyclopentolate 1% is the preferred choice. (College of Optometrists 2019, Farhood 2012)

Question 16

what is the ideal drug for refraction

Answer 16

fast-acting,
give adequate cycloplegia
last long enough for the refraction to take place
have no local or systemic side-effects.

Question 17

what is cycloplentalate best for

Answer 17

refraction

Cyclopentolate does well on all of these although there are potential local and systemic side effects.

Local: ocular stinging, allergy.

Systemic: CNS disturbances such as ataxia, incoherent speech, restlessness, hallucinations, hyperactivity, and disorientation. Children should be monitored for 45 minutes post-instillation.

Question 18

how is atropin used in optical penalisation

Answer 18

In 2002, the Paediatric Eye Disease Investigator Group (PEDIG) published the results of their multi-centre randomised clinical trial involving 419 children with amblyopia.
They were assigned to either a patching group or atropine group.
Visual acuity in each eye was measured after 6 months and compared and they found no significant difference between the treatment modalities. (PEDIG 2002)

Question 19

why is atropine best used in optical penalisation

Answer 19

Atropine 1% is placed into the better seeing eye, thereby preventing that eye from having a clear stimulus at near and forcing the amblyopic eye to read.
It is also possible to reduce any hyperopic correction in the better seeing eye to also cause blur at distance.
1% atropine was instilled everyday and the children were provided with sunglasses and advised to wear a hat.

Question 20

how often should atropine be administered

Answer 20

Currently, weekend atropine or twice-weekly instillation of atropine 1% is indicated. (Taylor and Bryant 2012)
Close monitoring of adherence is essential and can be easily checked by observing pupil dilation (better by doing dynamic ret!).
If the vision does not respond then conventional patching should be considered.
The long-lasting action of atropine is the main reason why it is preferred to Cyclopentolate for amblyopia therapy.

Question 21

what is uvetis

Answer 21

In particular anterior uveitis (iritis). Uveitis is the inflammation of the uveal tract and anterior uveitis is the inflammation of the iris and ciliary body.
The acute type typically presents in young adults as a uniocular painful red eye which has affected the vision.
The patient is photophobic and may have a history of systemic inflammatory disease, eg rheumatoid arthritis.

Question 22

what would you see on a slit lamp with uveitis

Answer 22

marked circum-limbal injection
cells in the anterior chamber
flare
keratic precipitates
possibly hypopyon
the pupil may be misshapen due to posterior synechiae.

Question 23

what is the management of a patient with uveitis

Answer 23

The patient will hate you looking with the slit lamp!
The chronic type may be much more subtle in it’s presentation. Both types (acute and chronic) require a doctors opinion.
Cyclopentolate 1% is given to break/prevent the synechiae and to reduce the pain due to the ciliary body/iris being inflamed by preventing the movement associated with accommodation.
Steroids are also prescribed by the doctor to reduce the inflammation.

Question 24

how is a cillary spasm alleviated

Answer 24

In some cases of corneal abrasion, the ciliary muscle can go into a spasm which is extremely uncomfortable.
Cyclopentolate 1% can be administered to alleviate this spasm through cycloplegia.

Question 25

what is mydriasis

Answer 25

All anti-muscarinics will cause pupil dilation (mydriasis) as the sphincter papillae of the iris receives parasympathetic innervation.
Therefore, stopping this muscle from working leaves the dilator papillae to exert it’s affect without competition and the pupil will dilate.
Therefore, stopping this muscle from working leaves the dilator papillae to exert it’s affect without competition and the pupil will dilate.
If one stimulates the dilator papillae using an adrenergic agonist (sympathomimetic) then this will result in mydriasis.

Question 26

what is a combination approach and how is it used

Answer 26

Often, a combination approach is used which creates mydriaisis using one drug from each class. Eg phenylephrine 2.5% and tropicamime 1%.
This is particularly seen when checking infants for signs of retinopathy of prematurity and in adults when the peripheral retina needs to be seen in suspected retinal detachment.
NOT atropine with phenylephrine!!!

Question 27

how is atropine 1% used

Answer 27

Rarely used as a mydriatic due to long time of onset, long lasting effect and potential toxicity.
Only used if other drops ineffective or allergy. Eg heavily pigmented irides. POM

Question 28

how is clyclopnetalte 0.5% used

Answer 28

More frequent use than atropine but not drug of choice as cycloplegic effect too great.
Again used in case of ineffective dilation with Tropicamide or allergy. POM

Question 29

how is tropicimide 0.5% used

Answer 29

sufficient to produce 6mm pupil diameter in young healthy adults (Siderov and Nurse, 2005)
Usually tolerated better than the above due to rapid onset and faster recovery and usually leaves some residual accommodation. POM

Question 30

how is pheneleyrphyine 2.5% used

Answer 30

Available as Minim. Pharmacy medicine (P)
Cautions:
Asthma;
corneal epithelial damage
darkly pigmented iris is more resistant to pupillary dilatation and caution should be exercised to avoid overdosage
diabetes (avoid eye drops in long standing diabetes)

Question 31

what should you be cautious of with phenelyerphine

Answer 31

mydriasis can precipitate acute angle-closure glaucoma in the very few children who are predisposed to the condition because of a shallow anterior chamber
neonates are at an increased risk of systemic toxicity (in neonates);
ocular hyperaemia
susceptibility to angle-closure glaucoma

Question 32

what phenelyrphine interactions should you be careful of

Answer 32

BNFc cites 19 drugs with severe interactions, including with atropine. Please check the site for details.
Side effects:
Conjunctivitis allergic
eye discomfort
hypertension
myocardial infarction (usually after use of 10% strength in patients with pre-existing cardiovascular disease)
periorbital pallor
vision disorders

Question 33

what are the risks of 0.5% tropicimide and 2.5% phenelyrphone

Answer 33

As stated, in many clinics 0.5% Tropicamide and 2.5% phenylephrine are used in all healthy adults.
It is important to take a careful medical history prior to instilling these drops.
Also, there is a risk of precipitating angle closure glaucoma in susceptible individuals and assessment of the potential to close should be carried out on all patients.
In particular, older, phakic female hypermetopes of East Asian descent are particularly at risk.

Question 34

which patients should be dilated

Answer 34

The use of mydriasis is to aid the examination of the fundus, especially for indirect viewing techniques such as Volk lens examination with a slit lamp or headset mounted binocular indirect ophthalmoscopy.
It is particularly indicated when wishing to view the peripheral fundus, commonly needed to check for retinal tears following posterior vitreous detachment (PVD).
Ensuring adequate mydriasis is essential but using too much of any of the agents mentioned here increases the risk of systemic absorption and raises the possibility of systemic effects.