Cycloplegics Flashcards
What happens as get older
Accommodation reduces
What does duanes classical curve show
Amplitude or width of accommodation as changing with age = declines as older
Why use cylcoplegics
Optometric uses
*Assessment of refractive error - latent hyperopia = accommodative muscles are used to increase the eyes focusing power
*Penalisation - instead of occlusion
*Adaptation to spectacles (rare) – vision clear only with glasses
Additional ophthalmological uses
*Anterior uveitis – dilating pupil and alleviating ciliary spasm
*Corneal abrasion - alleviate ciliary spasm
What optometric indications would make you want to use cyloplegics
From H and S
- Symptoms
- Asthenopia = fatigue, blurred vision, pain in eyes
- Reading difficulties
- History
- Manifest deviations
- Family history
- Refractive error at an early age
-Manifest deviations
From clinical tests:
- Binocular vision anomaly
- Manifest eso deviation Sometimes if latent deviation
- Fluctuating ret
- Large difference between subjective and objective
- Poor fixation
- Accommodative anomalies
- Visual acuity reduced
Properties of a cycloplegic
- Rapid onset
- Adequate depth of cycloplegia
- Adequate duration
- No stinging
-No mydriasis - No toxic effects – Local AND systemic
- Large pupil
- Drops sting / duration of onset of cycloplegia
- Unnatural conditions
Effects of cycloplegia - how is cycloplegia caused
- Initially mydriasis
- Iris located anteriorly to ciliary muscle
- Unnecessary side effect - Cycloplegia
- Paralysis of the ciliary muscle, resulting in loss of accommodation
- Because of the paralysis of the ciliary muscle, the curvature of the lens can no longer be adjusted to focus on near objects
- Paralysis of the ciliary muscle, resulting in loss of accommodation
- Reduced tear secretion = dry eye
Which parts of eye does antimuscarinic agents affect
- Lacrimal gland
- Iris sphincter muscle
- Ciliary body
Advice before instillation
Advice for parent/guardian
* Explain need to use
* Onset
* Duration
* Expected side effects = temporary blurred vision until effects wear off
* Caution
Advice for child
* Explain might feel drop on eye
* 1dropof proxymetacaine first?
– RCOguidelines
What happens if consent is denied
Parent/Guardian:
* Explain advantages and disadvantages
* Note refusal on record
* If concern for child great refer to GP
Child
* Gillick competent = child agrees
* Record all discussions on notes
* If concern for child great refer to GP
How to instil drops
- Instillation-lying down may help.
- Sometimes drop onto eyelashes can help
Checking for cycloplegia
*Measure accommodation
*Check ret reflex
Cycloplegic Retinoscopy
- Sit younger child on parent’s knee
- Can ask px to fixate upon light of ret
– Ensures retinoscopy is conducted upon axis - No need to fog other eye
- Can try using lens rack
- Observe central movement – 3-4mm
- Ignore movement in periphery
Examples of cycloplegic drugs
Strongest to weakest:
- Atropine 1%
- Additional supply or independent prescriber status
- Associated with numerous side effects
- Cyclopentolate
- 0.5 and 1%
- Most commonly used
-Homatropine 1%
- Additional supply or independent prescriber status
- Tropicamide 1%
- Weakest drug only effective in adults
- Used mainly as mydraitic
Features of atropine sulphate
- Naturally occurring compound “Belladonna” deadly nightshade
- First muscarinic antagonist used in medicine
- Toxic agent
- POM = For use and supply by additional
supply optometrists and used and prescribed by independent prescribing optometrists
Atropine- Preparations
- Atropine Sulphate: eye drops, (non-proprietary)
– 0.5% atropine sulphate
– 1.0% atropine sulphate - Atropine Sulphate: eye ointment
– 1% atropine sulphate (non- proprietary) - Minims
- 1% atropine sulphate (Bausch &
Atropine- Dose
Adults and children > 3 months
*Eye drops
– 1 drop (1%) twice per day for 1-3 days before refraction
*Ointment
– 2 times a day for 1-3 days before refraction
Why is atropine ointment preferable
– Systemic toxic effects
– Prolonged contact with eye
Atropine -Timing
After instilling 1 drop of 1%:
Mydriasis
–Commences in 10-15 mins
–Maximal in 30 – 40 mins
–Recovers in 3 – 7 days
Cycloplegia
–Commences in 30 mins
–Maximal in 1 – 3 hours
–Recovers in 3 - 7 days
After 3x twice daily instillations
Mydriasis
–Recovers after 10 – 14 days
Cycloplegia
–Recovers after 7 – 10 days
–Adequate near vision recovers after 4 – 5 day
Atropine-Tonus allowance
- Ciliary muscle has dependant and independent tone
- Allowance needs to be made for dependent tone - Spherical power only needs to be adjusted in less
positive direction - -1.00DS for low myopes and hyperopes
- 0.00DS for moderate and high myopes
Atropine - Cautions
Contraindications
- Known allergy to atropine or component of the preparation
- Narrow angles - not so present in children
Cautions
- Children < 3 months
- Elderly or debilitated
- Down’s syndrome
- Children with brain damage
- Hypersensitivity
- Soft contact lenses = multi-dose containers contain benzalkonium chloride – do not use if lenses worn Intermittent manifest deviations
Pregnancy and Lactation Interactions
Atropine Sulphate side effects on eye
- Transient stinging
- Blurring
- Photophobia
- RaisedIOP?
- Repeated use
– Hyperaemia
– Oedema
– Itching, irritation
– Follicular conjunctivitis
Atropine Sulphate side effects on body
- Toxic effects
– Dry as a bone: Dry mouth and skin
– Red as a beetroot: Flushing, Increased body temperature
– Blind as a bat: Cycloplegia
– Mad as a hatter: CNS effects –ataxia, hallucinations, confusion, difficulty in speaking - Tachycardia
- Death from respiratory depression = more likely in children. 3 gram tube can be fatal to a small children
Atropine - additional uses
- Used to treat amblyopia = instead of occlusion
- Instilledinto“better eye”
- Preventsaccommodation
- Used when child will not tolerate patching/ first choice?
- Excellent results
Features of Cyclopentolate Hydrochloride
- Commonly used cycloplegic
- Synthetic drug
- Not commonly used as a mydriatic by Optometrists
*0.5% more useful as a mydriatic
*Ophthalmologists - Stings
Cyclopentolate- Preparations
- POM for use and supply by all optometrists
- Mydrilate: eye drops
– Mydrilate (Intrapharm)
– 0.5% cyclopentolate HCL
– 1.0% cyclopentolate HCL
– Stored between 2 - 8°C - Minims
– 0.5% cyclopentolate HCL
– 1% cyclopentolate HCL
– Store below 25°C, protect from light
When would you use 1% or 0.5% cyclopentolate
Up to age 12 yrs– usually 1%, if iris pigmentation is light then 0.5% may be suitable
CAUTION-very young px
Cyclopentolate - Timing
Cycloplegia:
- Commences after a few minutes, maximal in 30-60 minutes
- Recovery 4-12 hours
Mydriasis:
-Commensces after 30 mins
-Recovery 24-48 hours
- Residual accommodation ≤1.50D
- Time scale variable
Cyclopentolate – Tonus allowance
- No tonus allowance made
- Almost always give full Rx found
- Exception
– Hyperopia and exo deviation
– Myopia and eso deviation
Cyclopentolate - Cautions - which px’s
- Young children
- Debilitated patients
- Elderly
- Avoid over dosage in darkly pigmented eyes
– Compressing the lacrimal sac for 2-3 mins after instillation of the drops to make sure maximum amount of drug in eye - Pregnancy and lactation
– Unknown use only if risk to mother outweighs risk to foetus - Hallucinations and CNS effects reported with concentrations
Cyclopentolate side effects
Ocular:
- Transient stinging
- Transient blurring
- Photophobia
- Raised IOP?
- Conjunctival hyperaemia and oedema
- After prolonged administration = irritation, hyperaemia, oedema, conjunctivitis
General-body:
* Dose related – Children
* CNS effects
* Dry mouth
* Flushing
* Tachycardia
* Urinary symptoms
* GI symptoms
Cyclopentolate - additional uses
- Adaptation to spectacles
- Children almost always adapt well
to hyperopic prescriptions - Use 1% cyclopentolate daily for 2/52
– Accommodation abolished
– Clear vision only obtained via
spectacle wear
– Child usually then accepts spectacle wear = as clear vision only obtained when wearing them - For anterior & posterior uveitis and
posterior synechiae breakdown: 1 - 2 drops (1%) are instilled every 6- 8 hours. - For alleviation of ciliary spasm: 1 drop (1%) 2-3 times per day
Duration of mydriasis
24 hours
Homatropine Hydrobromide
POM
–Additional supply or independent prescriber
–1% multi-dose containers (non- proprietary)
–Store below 25°C, protect from light
– Used for dilating pupil in anterior uveitis
– Alleviation of ciliary spasm following corneal abrasion
- Mydriasis~30-40mins
- Recovery24-48hrs
Tropicamide Hydrochloride - what does degree of cycloplegia depend on and what is the recovery and mydriasis time
Degree of cycloplegia dependent upon:
- Age
– Only indicated for cycloplegic refraction in older patients in late teens or older)
– 1% strength only suitable *Iris pigmentation
- Degree of cycloplegia dependent upon pigmentation - in blue eyes its more
Effects after instillation of 2 drops of 1% solution:
– Mydriasis after ~15 minutes * Recovery ~8-9 hours
– Cycloplegia maximal 30 mins * Recovery ~6 hours
