AMBLYOPIA + REFRACTIVE ADAPTATION + PATCHING + ATROPINE + EMMATROPISATION

Question 1

What is the pass mark for visual school screening in Scotland?

Answer 1

• 0.2 logMAR Keeler or 0.1 logMAR Sonksen
• 0.1 logMAR Kays pictures
• Or referred if manifest dev / sig phoria / OM defect / reduced conv + 20 ^ / No co-op

Question 2

What is the definition of anisometropia?

Answer 2

• Difference of 1D or more between two eyes

Question 3

Amblyopia definition and types?

Answer 3

Developmental condition characterised by reduced vision in one eye, VA worse than 0.2 logMAR or corrected VA difference of 0.2 logMAR or worse, which is not due to abnormalities of fundus or pathology of visual pathway, but due to sensory impediment to visual development e.g.
- Stimulus Deprivation Amblyopia: Result of manifest strabismus
- Strabismus Amblyopia : result of manifest strabismus
- Anisometropia Amblyopia : result of difference in refractive errors between two eyes
- Ametropic Amblyopia : result of high degree of bilateral uncorrected refractive error
- Meridional Amblyopia : result of uncorrected astigmatism

Question 4

What do all patients have to undergo before commencement and after commencement of treatment? (Amblyopia therapy)

Answer 4

• pupil check, cycloplegic refraction, fundus and media examination

Question 5

Stimulus deprivation amblyopia?

Answer 5

• Although there is less robust evidence of the effectiveness of occlusion in cases of stimulus deprivation amblyopia , patients with SDA usually need more aggressive occlusion regardless of age.

Question 6

When will patching have no effect?

Answer 6

• If fundus has hypoplasia (not enough cells in fovea during development)

Question 7

Mechanisms of amblyopia:

Answer 7

• Light deprivation: no stimulus to retina
• Form deprivation: retina receives a defocused image
• Abnormal binocular interaction: non-fusible are formed on the fovea

Question 8

Prevalence of Amblyopia:

Answer 8

2-5 % of kids in the UK

Question 9

Severity of Amblyopia:

Answer 9

MILD – 0.2 - 0.3 logMAR
* MODERATE - >0.3 – 0.7 logMAR
* SEVERE - 0.7+ logMAR

Question 10

What is definition of anisometropia?

Answer 10

• Difference of 1D or more between two eyes

Question 11

What are the types of anisometropia?

Answer 11

Mixed anisometropia: One eye refractive error is myopic, and one eye refractive error is hypermetropic.
* Simple hypermetropic astigmatism
* Simple myopic astigmatism

Question 12

How to transpose rx?

Answer 12

1. Add the sphere and cylinder powers to determine the new sphere power.
2. Change the sign of the cylinder.
3. Change the axis by 90 degrees

Question 13

How much refractive error risks amblyopia?

Answer 13

• Children with >+3.50DS increased risk of amblyopia & squint

Question 14

How much refractive error do you give for anisometropia?

Answer 14

• Give full Rx in amblyopia

Question 15

How much refractive error do you give for hypermetropia?

Answer 15

• In Accommodative ET – full +
• XT or X - <+3.00DS left uncorrected
• • without strabismus – give if above expected for age

Question 16

How much refractive error do you give for myopia?

Answer 16

• Weakest – that gives best corrected VA

Question 17

Recommended time length to achieve maximum VA in refractive adaptation?

Answer 17

Recommended time length to achieve maximum VA 18-22 weeks (Paediatric Eye Disease Investigator Group (2012)
* Greatest change in first 12 weeks. Asper et al. (2018)
* Continued VA improvement up to 30 weeks (Paediatric Eye Disease Investigator Group (2006)
* Refractive adaptation phase: review within 3 months of prescribing glasses to establish full-time glasses compliance and improvement in visual acuity.

Question 18

Refractive Adaptation : how much cases of amblyopia with glasses alone?

Answer 18

• Resolution of amblyopia with refractive correction alone in 20% of kids (Stewart et al., 2004)

Question 19

Refractive adaptation VA average improvement?

Answer 19

• Amblyopic VA - average improvement of 0.24 logMAR with refractive adaptation alone in 18 weeks. Stewart & MOTAS et al. (2004) = 2 visits

Question 20

What are types of occlusion?

Answer 20

• Total occlusion – occlusive patch, blenderm, frosted lens
• Partial occlusion – bangerter foil (< 0.05 logMAR difference in VA improvement between 2 hours patching and 0.3 BF. BF better tolerated, PEDIG 2010)
• Full time occlusion – all waking hours/24 hours
• Part time occlusion – specific periods of time/certain activities

Question 21

What are the patching recommendations for moderate amblyopia ?

Answer 21

2 hours = 6 hours patching for <7 year olds (PEDIG 2003)
* 2 hours + near tasks = 2 hours without near tasks (PEDIG 2008)
* When baseline acuity is 0.6 to 0.7, more hours may improve acuity faster (PEDIG 2003)

Question 22

What are the patching recommendations for severe amblyopia ?

Answer 22

6 hours = full time patching for <7 year olds (PEDIG 2003)
* high dose rate achieved a successful outcome more rapidly but did not improve outcome

Question 23

How many hours for 1 line VA improvement?

Answer 23

• log unit (1 chart line) improvement per 120 hours of occlusion (MOTAS 2004)
• 224 hours gave 0.1 logMAR increase in VA (white and walsh 2022)

Question 24

Max hours for occlusion ?

Answer 24

252 hours occlusion = 80 % done (MOTAS 2004)
* 504 hours occlusion required to reach outcome VA (MOTAS 2004)

Question 25

compliance patching

Answer 25

• Compliance better when starting VA better (refractive adaptation)
• Dose rates of 2-6 hours resulted in same final outcome
• Regular supervision / contact with orthoptist improves compliance and may shorten treatment phase.

Question 26

Age and patching? For older kids

Answer 26

Amblyopia improves with optical correction alone in about one fourth of patients aged 7 to 17 years, although most patients who are initially treated with optical correction alone will require additional treatment for amblyopia.
* For patients aged 7 to 12 years, prescribing 2 to 6 hours per day of patching with near visual activities and atropine can improve visual acuity even if the amblyopia has been previously treated.
* For patients 13 to 17 years, prescribing patching 2 to 6 hours per day with near visual activities may improve visual acuity when amblyopia has not been previously treated but appears to be of little benefit if amblyopia was previously treated with patching.
* PEDIG 2005

Question 27

When are patching/atropine patients reviewed?

Answer 27

• Review every 6-8 weeks after commencement of treatment to monitor improvement and / or adjust the prescribed hours of occlusion. If acuity fails to improve by at least 4 letters each visit the occlusion dose should be increased i.e. from 2 to 4 to 6 hours.

Question 28

Atropine, how does it work?

Answer 28

• Paralyses the ciliary muscles to optically defocus the non-amblyopic eye
• Effect lasts for longer than other cycloplegics – up to 14 days
• Greater effect for near VA than distance
• Daily atropine Vs Weekend atropine

Question 29

Atropine in moderate amblyopia daily vs weekend ?

Answer 29

Mean VA after 4 months 0.2 logMAR with daily vs weekend (PEDIG 2004)
* ≥10 hours occlusion quicker improvement – no significant difference between all treatments at 6 months (PEDIG 2003)

Question 30

Atropine in severe amblyopia?

Answer 30

• 2 hours patching (1.8 lines improvement) vs weekend atropine (1.5 lines improvement) – (7 – 12 year olds in this study)- PEDIG 2009

Question 31

Atropine + Optical Penalisation?

Answer 31

• Non responders – could add optical penalisation although no great improvement in VA found when compared to atropine alone (about ½ line).

Question 32

Optical penalisation in occlusion treatment?

Answer 32

• Alone or in conjunction with Atropine
  o Lenses used to blur VA of better eye

*Total penalisation: Use of amblyopic eye for all distances. Add strong convex lens to the better eye

• Suggest the choice is based on degree of amblyopia

Question 33

Indications for use: atropine?

Answer 33

Mild – moderate amblyopia with no co-op to patching
* *VA static with other treatment
* *Older children with anisometropic amblyopia – social reasons
* *Latent nystagmus component

Question 34

atropine vs atropine + optical peanilisation

Answer 34

180 children with moderate amblyopia
*Weekend atropine vs weekend atropine + optical penalisation (plano lens)
*18 weeks
o2.8 lines improvement in atropine + optical penalisation
o2.4 lines improvement in atropine alone
*More patients in atropine + optical penalisation had reduced sound eye VA – no reports of persistent reverse amblyopia (PEDIG 2009)

Question 35

who is atropine not suited towards?

Answer 35

• atropine is not suitable for aphakic / pseudoaphakic children, patients with Down’s syndrome or those with a known history of cardiac disorders, raised IOP, narrow angles or known hypersensitivity to atropine or any component of the preparation

Question 36

Suppression and patching?

Answer 36

All patients aged 6 and above with no motor fusion should be evaluated with Sbisa bar or Bagolini filter bar prior to amblyopia treatment and monitored closely. If diplopia occurs then treatment should be stopped immediately. It should be noted that the Bagolini filter bar (filters 1-16) and Sbisa bar (filters 1-17) are not equivalent . Monitoring of suppression should be undertaken using the same bar at each visit

• Filter 7 is most often used as the point at which treatment is stopped

Question 37

When and how to stop occlusion?

Answer 37

• Amblyopia treatment should be tapered once optimum equal visual acuity obtained has been reached to reduce the risk of recurrence or reversing amblyopia. Most that did alternate started treatment before age 2. (Campos & Gulli 1985) 42% recurrence when treatment not reduced and only 14% when reduced from 6-8 to 2 hours before discontinuing. (PEDIG 2004)
• No significant improvement in the amblyopic eye when occlusion dosage increased after 2 consecutive visits with full compliance with treatment and no change in refraction and fundus exam.
• Failure to improve, or deterioration of acuity, within 4-6 months of the commencement of amblyopia therapy (when compliance is good), should prompt re-refraction and re-examination of fundus and possible further investigations.
• Complaints of binocular diplopia = Definitely stop if density of suppression reduces with risk of intractable diplopia

Question 38

Patching and quality of life?

Answer 38

• Questionnaire - focus group of patients, orthoptists and ophthalmologists
• Children were hardly troubled by the patch when playing games on the computer, watching TV or colouring (item 5), whereas parents thought that they were really troubled (Fig. 1e).
• Almost all children (54), could play well with other children when wearing the patch (item 6).
• Most all children (57) were not laughed at or bullied by other children when wearing the patch (item 10), and almost all parents agreed (Fig. 1j)
• Children’s quality of life during occlusion therapy is affected less than their parents think

Question 39

Atropine important info:

Answer 39

Pupil responses should be checked to ensure the correct eye has been dilated.
All parents or guardians to be given verbal and written information regarding the use and side effects atropine drops / ointment and a copy of the atropine information leaflet (Appendix IV). A copy may also be issued for the child’s school.
Any patient experiencing an adverse reaction to atropine should be seen by a doctor, the event recorded in the notes with any unexpected effects being reported to the Medicines and Healthcare products Regulatory Agency (MHRA) via the Yellow Card Scheme immediately.
i) locally: irritation, photophobia, transient stinging, hyperaemia, oedema, conjunctivitis, raised IOP.
ii) systemically: ataxia, restlessness, hallucinations, dry mouth, difficulty swallowing or talking, flushing and dry skin, irregular heartbeat, palpitations, urinary urgency and retention, constipation, confusion, nausea, vomiting, giddiness. Systemic effects are more likely with drops than ointment.32

Question 40

where do you report atropine side effects

Answer 40

Any patient experiencing an adverse reaction to atropine should be seen by a doctor, the event recorded in the notes with any unexpected effects being reported to the Medicines and Healthcare products Regulatory Agency (MHRA) via the Yellow Card Scheme immediately.

Question 41

What are problems during treatment of amblyopia?

Answer 41

1. Occlusion amblyopia
   *Amblyopia in the fellow eye caused by treatment *Most likely in total occlusion
   *Sometimes seen in atropine treatment *Reports of development after one week occlusion in children <18 months *Can occur up to 2 years old
   Prognosis: *VA can generally be recovered
   Treatment: *Stop treatment and swap to other eye with careful supervision
2. Interactable diplopia
   *Luckily rare *Older children without BSV potential
   *Density of suppression monitored during treatment *Binocular function monitored
   Prognosis *Generally - unlikely to persist
   Treatment *Stop treatment at first sign of diplopia+ don’t draw attention to it
3. Dissociation
   *Cases of latent or intermittent strabismus
   *More likely in >5 year olds
   *Those with inadequate motor fusion
   Prognosis: *Good likelihood of functional result
   Treatment: *Treatment stopped and patient monitored
   *May spontaneously restore BSV
   *Prisms to fuse diplopia then strength reduced
   *Surgery if persists
4. General
   * Allergic response to Patch or Atropine
   *Infection incubated by patch
   * Psycho-social implications - increased likelihood of bullying & stigmatisation
   *Danger socially due to disorientation

Question 42

Specific treatment for amblyopia types? 1. Stimulus-deprivation Amblyopia:

Answer 42

1. Stimulus-deprivation Amblyopia:
   *Most common cause is cataract
   *Most severe is unilateral congenital cataract
   *Removal of cataract within 6 weeks in unilateral and 10 weeks in bilateral
   *Correction with IOL or CL
   Prognosis: VA Reasonable – improves if cataract acquired early infancy rather than truly congenital but Stereopsis rare
   Treatment: Intensive total occlusion as soon as possible after optical correction
   *1 hour per day per month of child’s age (until 8 months)
   *>8 months: all waking hours every other day or ½ waking hours every day
   *Limitations in testing & monitoring VA accurately in this age group

Question 43

Specific treatment for amblyopia types? 2. Strabismic Amblyopia

Answer 43

*Monitor near and distance VA
*Explain watching for alternation of strabismus to parents

Prognosis: Already covered
*Possible improvement in angle in ET patients post occlusion therapy
*Some not then requiring strabismus surgery
*Patching can reduce eccentric fixation – should be monitored regularly

Treatment: Improvement to be gained from FT refractive error correction first
*Occlusion still generally treatment of choice in departments
*Total occlusion – varying durations
*Increase in hours if no improvement
*Swap treatments
*Add optical penalisation
*Atropine in nystagmus cases

Question 44

Specific treatment for amblyopia types? 3. Anisometropic Amblyopia

Answer 44

*May be detected late - >5 years old
*Preschool vision screening
Prognosis: Still good – despite late diagnosis
*Central fixation increases chances of 0.00 LogMAR
Treatment :
*Refractive adaptation *Patching or atropine
*Consider CLs if marked anisometropia
*High aniso-myopia tend to respond less well

Question 45

Specific treatment for amblyopia types? 4. Ametropic Amblyopia

Answer 45

*Aim to achieve useful VA with refraction
Prognosis
*Normal VA level rarely obtained
*Improvement normally more gradual over 2-3 years
Treatment
*Constant glasses wear
*Some non-tolerance more likely in older children

Question 46

Future of amblyopia treatment…

Answer 46

Video games, perceptual learning, refractive surgery

Question 47

Emmatropisation:

Answer 47

Emmatropisaion is the process by which the refractive state of the eye changes and is mostly complete by 3 years old, from birth.
Its the reduction in mostly hypermetropia and astigmatism and can eradicate around +3.00 DS and +1.50 DC (astigmatism)

Passive emmetropization refers to normal eye growth as eye size increases, power of optical components decreases and proportionally refractive error decreases.

Active emmatropisation describes the visual feedback mechanism in the control of eye growth (feedback from eye which is blur and stimulates cortex to keep/stop growing the eye)

The eye axial length elongates, the lens becomes thinner and the cornea becomes thinner. The cone cells elongate and migrate towards the centre of the retina to form the foveal pit and bunch closer together so there’s less space for light to fall in-between and the signal getting lost.

The Critical period is where vision and BV connections are being rapidly formed and this period lasts until roughly 2 y/o. Any disruption during this time can have a severe effect on the overall visual outcome.

The sensitive period is when the visual system is still developing therefore disruptions can still have an effect on the overall visual outcome but are not as severe, and lasts up to 8-10 y/o.
The earlier the deprivation, the more severe the visual loss.

Amblyopia exists when the process of emmetropization has failed and one eye (or rarely both) have not developed the neural connections from the eye to the brain due to disruption to the visual system