Strabimus Managment Flashcards
Goal of strabismus
Fusion and alignment
How can we manage strabismus
- correction of refractive error
- added lenses
- prism (NRC)
- occlusion-for amblyopia or suppression treatment
- VT (accommodation, suppression, or vergence ranges)
- Botox
- surgery (large angle)
Strabismus prognosis
-the early the intervention after the onset, the lower the chance of sensory adaptation
Sensory adaptations
- amblyopia
- suppression
- anaomalous correspondence
Strab prognosis is worse with
Esotropia
ARC
Constant unilateral strabismus
Sensory adaptations
Amblyopia
Suppression
ARC
Importance of strab management
- to prevent debilitating consequences
- to improve quality of life
How could strab affect quality of life
Lower self esteem
Symptoms
Unable to perform hobbies or task
Appearance
Management for strab needed to
Offer better acuity
Offer some fusion
Provide better appearance (cosmetic goal)
Eliminate adaptations such as head turn or tilts, or anomalous correspondence
Correction of refractive error in strab
- to offer the best acuity for BV and clarity
- fully correct anisometropia and astigmatism
- full hyperopia easier to accept in younger children
- in older children, give the amount of plus that offer best alignment
Why would you not fully correct an older child
If not accepting full plus
Cutting plus on refractive error
Cut anisometropia by the same amount
- could take down the amount of plus in the future, as long as alignment is maintained
- follow up for VA, fusion and deviation
If someone has an esotropia, full or partial correction
Full
Cutting plus in someone with anisometropia and no strab
But by the same amount
Added lenses for strab
- additional alignment and fusion
- for example in children with high AC/A, addled lenses could offer affiiotnal alignment
- bisect the pupil in bifocal in younger children
- recommended full time wear
Where should the add be placed in kids with strab
Bisect the pupil
Added lenses for strab (plus or minus)
- added minus can be used in chidlren with IXT (since there is already some level of fusion)
- the accommodative drive is increased and the fusional vergence collapses the angle
- works very well in IXT kids
- do not want to over minus in cases of convergence insufficiency or presbyopia or accomodative problems
Prism for strab
- shift the image to the fovea
- prism can be fresnel or ground in
- do not over do it. Can try prism in cases with deviations as much as 16-18PD. Greater than this needs surgery because the deviation becomes visible
- for it to work, VA has to be good, no AC and/or suppression
When can fresnel prisms be used
In acute strab, but larger amounts can compromise the VA
What else could prism be good for
Also useful in anomalous head positioning in nystagmus, palsies, decompensatiyng phorias
VT for strab
- to improve fusional abilities, acommodation
- work on suppression
- has to be tailored to the patient
- may work well in patients with existing fusion
- works well with convergence insufficnicy, XT
- if not in a VT practice, you can refer
- can try home orthoptic programs as well
Botox for strab
- binds to nerve endings to interfere with ACH action
- there is a temporary paralysis of the muscles and there is some contracture of the opposing muscle, this could be permanent
- varying repsosne and improvement compared to surgery
- only have 4 randomized controlled trials on this
Referral for surgery for strab
- surgery to achieve close to normal alignment
- for large angles (more than 15PD)
Referral after addressing
- refraction correction
- the use of added lenses
- the use of prisms
- VT (as needed)
Why do we not want to give large amounts of prism in glasses
Because it will be too heavy
-above 15PD is too much
Surgery contraindicated for
Accommodative esotropes
Watch intermittent exotropia s that have good control
No surgery for smaller angles until every thing possible has been tried
Make sure the amblyopia is treated
VT can be done before nad after to build fusional vergences
Timing for referral for surgery
- the early the referral the better for infantile strab. Offers better chance to retain BV
- educate the family that there could be a need for revisions in the future
Strab surgery performed to
Tighten or loosen the muscles
Recession
The muscle is detached and reattached further back
Resection
The muscel is shortened and reattached to its original insertion site
Adjustable sutures
Alignment can be adjusted while the patient is in recovery (vs permanent)
- to fine tune
- to reduce reoperation rebates
Spiral of tillaux and surgery
Need to know how far from the limbus the muscles are to know how much they can recess it
Other management considerations for strab
- full eval to rule out other pathology
- managemtn must be tailored for each child
- may habe to combine differnt treatment options for desirable results
Pseudoesotropia
- appearance of ET when eyes are actually straight
- hirschberg and cover test wil be normal
- seen in children with wide, flat nose bridges with prominent epicanthal folds and small interpupillary distance
- pinch the nose bridge
- the appearance improves with age
- these children may actually have a deviation though
Infantile esotropia
- onset is between birth and 6 months
- large constant esotropia (>30PD)
- family Hx of ET likely
- other neurological or developmental conditions seen in these children (cerebral palsy, hydrocephalus, prematurity)
- many have cross fixation- using the addicted eye to look into the contralateral view
Other variable findings of infantile esotropia
- amblyopia likely in constantly deviated eye (even with cross fixation)
- A or V pattern
- DVD-dissociated vertical deviation
- OIO-over action of inferior oblique
- latent nystagmus
- anomalous head positioning
- low hyperopia may be present
- about 30-50% of all esotropes
Management of infantile esotropia
- comprehensive eval
- full cyclo refraction. Rules out early onset of accommodative ET
- surgery allows some degree of fusion
Accomodative ET
- onset between 6 months and 7 years (average age of onset is 2.5y ears)
- starts intermittently and then may beceoms constant
- family Hx
- trauma can precipitate it
- amblyopia often present with large constant and unilateral angles
- diplopia May result, followed by active suppression
Types of accommodative ET
- refractive accommodative ET (due to high hyperopia)
- non refractive accommodative ET (due to AC/A high)
- mixed accommodative ET (due to higher hyperopia and high AC/A)
About 50% of all ET have an accommodative component
Refractive accommodative ET (high hyperopia)
- due to uncorrected hyperopia and insuffienct FV to diverge
- ET could be about 20-30PD
- could be intermittent, alternating with asthenoopia
- similar deviations at D and N
- due to hyperopia as little as +2.00D or more
If hyperopia is >5D, isoametropia amblotia devleoeps because patient has too much blur and will be unable to try to acommodative
prevalence of ET and amount of hyperopia
As amount of hyperopia in the less hyperopic eye goes up, increased prevalence of amblyopia
Managemtn of refractive accommodative ET
- comprehensive eval
- cyclo
- full hyperopic Rx for full time wear ASAP. If not, residual ET may no longer respond to hyperopic correction
- start amblyopia treatment if VA doesnt full improve Rx
