BVP - Optometric Management of Esotropic Strabismus - Week 5 Flashcards
List six differential diagnoses for esotropia.
Accommodative esotropia
-including partially accommodative esotropia and accommodative excess
Non-accommodative esotropia
Pseudotropia
Infantile esotropia
Duane’s syndrome
Pathological syndrome
-6th nerve palsy
-other pathological esotropia
What is the most common strabismus?
Accommodative esotropia
What are three choices a child with significant hyperopia (+3D OD, +4D OS) can make regarding their accommodative esotropia? What do children with this Rx typically choose?
-Relax accommodation and blurred binocular vision
-Exert accommodation by 3D and have clear vision RE
-Exert accommodayion by 4D and have clear vision LE
Typically choose to accommodate by 3D or less - clear vision with minimal effort
With a child with the Rx +3D OD, +4D OS, who chooses to accommodate by 3D or less, what effect will the accommodation have on their fusion? what effect will this have on their left eye and what is a possible outcome?
The accommodation causes convergence, so she will have increased demand on fusion (divergence)
The left eye will have a blurred retinal image, causing amblyopia, decreasion fusion quality
Possible outcome is left eye esotropia driven by accommodative convergence, facilitated by left eye amblyopia
When should spectacles be prescribed for esotropia (3)?
Hyperopia is over +2.00D
If esotropia responds to plus lenses (positive Raab +3.00D test)
Hyperopia is less than +2.00D, but a high AC/A ratio
-convergence excess
What is the most important prognostic sign for optometric management of esotropia? Is this true even for hyperopia
Response to plus lenses
True even if hyperopia is less than +2.00D
Are you looking for a complete accommodative component when assessing esotropia response to plus lenses?
No, just a significant one
What is a way of checking esotropia response to plus lenses?
Raab +3.00D test
List three complications in diagnosing accommodative esotropia at the first visit.
You will not necessarily find all the hyperopia at the first visit
-25-35% will show more hyperopia after wearing hyperopic spectacles for a few weeks
The esotropia may respond better to the plus after a few weeks
The motor examination is done before the cycloplegic and cannot be reliably repeated as accommodation is paralysed
What is the gold standard cycloplegic in children under 4 and children with esotropia? List the dosage for under 6 months and older than 6 months.
Cyclopentolate
Under 6 months - 0.5%
Over 6 months - 1%
Compare the effects of 2x1% cyclopentolate with 1x1%.
About the same
How long do you need to wait after instilling cyclopentolate to do retinoscopy?
40 minutes
Compared to cyclopentolate, how much more plus does atropine reveal?
0 - 0.50D
What is a way of checking if you have found the maximum plus in a high hyperopia esotropia case?
Check that +0.50D over Rx reduces VA at least a line
+1.00D should bur by 3 lines
Can maximum plus be measured on a three year old?
Yes
Where should plus be put in accommodative esotropia? Explain why.
Accommodative esotropia has its origin in the fixating eye
Plus in front of the fixating eye will keep the strabismic eye straight
What causes the strabismic eye to turn in accommodative esotropia? What is the implication here in terms of prescribing?
The accommodative effort of the fixating eye
Prescribe the full plus to the sominant eye to treat the strabismus
In simple terms, what is happening with accommodative esotropia?
the child has learned to accommodate and break fusion to make the retinal image clearer in the dominant eye
What happens to accommodative esotropia if left untreated, and how long does it take? What develops in the first few days/weeks (2)?
Esotropia changes from intermittent to constant over weeks/months
Suppression develops in the first few days to weeks
Amblyopia develops in the first few weeks
What happens to the extraocular muscles (note which two) in untreated accommodative esotropia? After how long?
A decrease in the number and size of sarcomeres of the medial and lateral rectus muscles in the first 6-12 months
How long does it take for anomalous retinal correspondence to develop in peripherally and centrally with untreated accommodative esotropia?
Peripherally in the first few weeks
Centrally after 1-2 years
Consider a patient with changes to their extraocular muscles and anomalous retinal correspondence with untreated esotropia. How will the esotropia respond to plus lenses (2)? Explain.
Either:
Completely (non-accommodative esotropia)
Partially (partially accommodative esotropia)
Can subjective refraction be done in children under 8?
No, not really
In what four cases is dry retinoscopy recommended at the first visit?
If they have esotropia
If they are under 3 years old
If they have plus over 2.50D
If they are a spectacle virgin
Is dry retinoscopy acceptable for review appointments?
Yes
Is dry retinoscopy acceptable if the patient is wearing close to full plus? what does wearing plus do in this regard exactly?
Yes
Wearing plus makes the dry and wet retinoscopy the same
Explain the following prescriptions for constant esotropia (for a child):
Full hyperopic correction
Slight overcorrection
Full hyperopic correction - necessary
Slight overcorrection - appropriate
To what VA should maximum plus be pushed?
6/6
Which patients should especially be pushed to maximum plus (3)?
Those with esotropia
Children
Those with amblyopia
When determining maximum plus, what must you demonstrate at second and later visits?
That an extra +0.50D will blur
List the five principles of treatment of any esotropia.
Give full plus (determined using cycloplegia)
Treat any amblyopia
Plus for amblyopic eye is for vision
Plus for the fixating eye is for the esotropia
Consider realignment for any residual esotropia after best amblyopia result and plus has been rechecked
When is surgery for esotropia typically considered (2)? Give an example where appropriate (1). What is the aim of the surgery?
For where there is still a cosmetic defect despite wearing full plus
If spectacles were never tried as not likely to work
-ie. +1.00D and 50ET
Aim is to provide acceptable cosmetic appearance
Consider a child who had surgery for esotropia. In what case would they need to wear glasses after surgery?
If there is more than +2.00D hyperopia
What is the success rate of esotropia surgery long term?
55% with one operation
