BV II Exam 3- Nicole

Why does Pseudo-ET look like an ET?

Wide bridge and prominent epicanthal folds give appearance of ET

• Epicanthal folds cover part of the nasal bulbar sclera

• Eyes look more ET when child looks to the right or left

• Nearly 50% of infants brought in for suspicion of ET have Pseudo ET!

How can we confirm a Pseudo-ET in an infant?

CT, Hirschberg, and Bruckner used to verify alignment

Why do we want to follow-up w/ Pseudo-ET babies after 6 mos to monitor alignment?

Study found that the prevalence of strab and amblyopia is higher in pseudoET's than normal population

RTC q6mo to monitor alignment

gaols of strabismus treatment

-normalize VA, eliminate amblyopia

-improve motor fusion potential- specs, prism, surgery, VT

-improve sensory fusion potential/ adaptations

-provide favorable cosmesis

accommodative esotropia

esotropia related at least in part ot use of accommodation

ETE will decrease with prescription of maximum plus glasses and/or bifocals

non-accommodative ET

esotropia that isn't exacerbated by accommodation, plus lenses provide no improvement in eso deviation

infantile esotropia

esotropia that presents by 6 mo and not significantly affected by accommodation

mechanically restrictive/ paretic esotropia

incomitant ETs

What is the most frequent childhood strabismus

Accommodative Esotropia

• 30% of children with hyperopia >+4.00D will develop ET by 3yo

• Runs in families (25% of 1st degree relatives have ET)

3 types of Accommodative Esotropia

• Refractive Accomm. ET

• non-refractive Accomm. ET

• partly Accomm. ET

refractive accommodative ET

hyperopia RE

normal AC/A

ET is eliminated with full plus Rx

Age of onset for Refractive Accommodative Esotropia

Typical age of onset 2.5 yo (6 mos - 8yo)

What causes Refractive Accommodative Esotropia?

• refractive errors +2 to +6, pt. is accommodating to clear refractive error --> ET

accommodative effort to overcome hyperopia causes eyes to cross

• Can be intermittent & variable due to accomm. effort

What is the typical magnitude of an Accommodative Esotrope

Typically moderate angle (10-45Δ)

Treatment of Refractive Accommodative Esotropia

full plus cyclopleged Rx

• Normal AC/A- ET eliminated with full plus hyperopic Rx

• High AC/A- ET eliminated with full plus hyperopic Rx + add

-Approximately 1/3 of comitant ET's will have complete

resolution of ET with hyperopic Rx

90% of all strabismus begin before _____ years of age

6

-Median age of onset 29 mos

(excludes paretic, mechanically restrictive, neuro origin)

What are some signs of a "dangerous" strabismus

anything that makes you think that strabismus was developed later in life

a) Later onset: >5 yo

b) Diplopia

c) Ptosis (new) + diplopia

d) Ocular neuro signs: Diplopia with incomitance, pupil anomalies, visual field defects

e) Other neuro signs Ataxia, speech disorder, cerebellar signs in children

f) Vomiting + diplopia in children

signs of refractive accommodative ET

ET magnitude is variable based on accommodative effort

goes away with fully plus

if ET is longstanding, pt develops suppression to prevent diplopia

important parent education for accommodative ETs

you may see more of an eye turn when the glasses come off

ET may have been intermittent before, but now accommodation is relaxed in specs, ET is more frequent

If hyperopic Rx aligns eyes at distance but leaves a residual ET at near, what can we presume about the AC/A

• Presume high AC/A

• Treatment with ADD power in a bifocal may be indicated*

-High ACA Esotropes with good alignment at distance may

have similar outcomes with or without a bifocal

• Prescribe least amount of plus to align eyes at near or give full near plus (+2.50-3 D add)

Where do we fit the add for children?

-FT BF seg height at lower pupil margin or split pupil (good control except at intermediate distances)

-PALs fit 2-3 mm above center pupil (better control for intermediate distance)

What refractive accomm. ET patients are able to be weaned out of their add?

For CE/ET's, those with lower AC/A's and smaller ET's more likely to wean out of near add

*Patients were more likely to discontinue bifocal use if they had surgery for Esotropia

Prognosis of refractive accomm. ET

-Some have excellent prognosis for NBV & stereo if ET resolved with Rx →May be able to wean out of add over time

prognosis was better if pt developed ET later in life (>2 yo) and shorter duration prior to treatment

-50% will show deterioration (return of Esotropia)

-some ET's will develop spontaneous consecutive exotropia.

Despite Tx of refractive accomm. ET with Plus Rx, up to 50% will show deterioration (return of Esotropia). What factors increase the risk of this?

• Higher calculated AC/A

• Earlier age of onset

• IOOA

• Amblyopia

consecutive exotropia

tropia angle was previously eso

sometimes occurs in refractive accommodative ETs despite treatment

Despite Tx with Plus Rx, some ET's will develop spontaneous consecutive exotropia. What factors increase the risk of this?

• earlier age of onset

• hyperopia of +5.00 or greater

• lack of stereo/fusion

• DVD

-No relationship between initial ET angle and initial XT angle

-seen most at distance

are BF actually helpful for high AC/A accommodative ETs

similar outcomes with and without bifocal

if bifocal improves function (fusion/ stereo) at near, Rx an add but otherwise maybe no benefit

research is conflicted

primary and secondary treatment of refractive accommodative ET

1. full wet ret Rx

2. BF with add for near ET if high AC/A

Non-Refractive Accommodative Esotropia

aka Convergence Excess ET

eso is not related to refractive error (no hyperopia) but is exacerbated by accommodation

• High AC/A

age of onset for Non-Refractive Accommodative Esotropia

2-5 yo

before 6

Non-Refractive Accommodative Esotropia etiology

high ACA causes eyes to cross when pt uses accommodation at near

often intermittent and variable depending on accommodative effort

average magnitude of deviation in Non-Refractive Accommodative Esotropia

initial treatment for Non-Refractive Accommodative Esotropia

Rx near add in BF to reduce accommodative effort if it improves fusion

rule out latent hyperopia with cyclo and spasm of near reflex

important things to rule out before diagnosing Non-Refractive Accommodative Esotropia

latent hyperopia- cylo pt

spasm of near reflex- MEM

typical age of onset for Partly Accommodative Esotropia

before 6 yo

etiology of Partly Accommodative Esotropia

accommodative effort to overcome hyperopia causes eyes to cross

typically a moderate- high hyperopia

plus specs don't correct full eso deviation

usually constant and unilateral> amblyopia risk

treatment for Partly Accommodative Esotropia

• Treatment with max plus (hyperopia Rx and add if high AC/A) still leave a residual ET

• Must employ additional treatment for residual ET> next ppt deck

• Prognosis for NBV reduced if residual ET isn't managed

We have a residual ET w/ Max plus, now what?

• Prism

• Surgery

• Therapy

• Pharmacology

What is the max amount of ground in prism you can use?

• Max ground prism 10-12Δ total

• 5-6Δ per lens is upper limit (can go higher with temporary Fresnel)

how does a BO prism work for esos

prism bends light toward the base and the image is shifted to the apexi which allows the eye to remain eso by decreasing divergence demand

What provides the greatest chance of success in Prismatic correction of residual ET

✓ Residual ET ≤10-12Δ small angles after plus lenses (partially accommodative ETs)

✓ No Amblyopia

✓ Stable deviation with prism (no prism adaptation)

✓ Normal fusion response with W4D (NRC)

When do we consider surgery for ETs?

• Better for larger deviations. (>10-15Δ)

• Earlier surgery associated with better outcomes (>6mos,

When do we consider VT for ETs?

• Reserved for small angle intermittent ET or small angle CET with compensating prism (good fusion potential)

• Hard to manage moderate to large ET with sensory adaptations using VT & hard to train divergence

What are the different Pharmacological options for treatment of ETs

• Botulinum Toxin (Botox)—Alternative to EOM surgery. Weakens injected muscle

• Bupivacaine HCL (BUP)—Alternative to EOM surgery. Strengthens injected muscle

• Cholinesterase inhibitors—Decrease accommodative effort and reduce accomm ET (no longer in use)

Botox MOA

"sausage toxin"

injection into muscle causes muscle paralysis and weakening by blocking acetylcholine release

in EOMS, effects last much longer than face muscles- can be permanent

onset takes 2-3 days

how does Botox compare to surgical outcomes for ETs

• Botox alone reported to have similar results to EOM sx for ET< 30Δ

• Maybe used in addition to surgery for larger angle ET (>60 Δ)

• Effects are often longstanding and sometimes permanent.

SEs of Botox inj. for Tx. of ETs

• Onset of effects takes 2-3 days

• Ptosis

• Over/under corrections (dosage guidelines

variable)

how is Botox used to treat ETs

injection into MR weakens MR

MOA of using Bupivacaine HCL (BUP) to tx. ETs

• Local anesthetic inj. into EOM to strengthen the muscle

- Myotoxic, causing necrosis of extra ocular muscle

- Initially, results in muscle weakening

- Muscle regeneration occurs during next 3-4 weeks

- Regenerated muscles have stronger myofibrils and increased muscle thickness

provides stable correction for 5-10 years

how is Bupivacaine used to treat ETs

injection into LR strengthens LR

how much deviation is Bupivacaine able to treat

5-10^

often mused as bilateral injection or with botox to increase treatment effect (15^)

T/F pharmacological treatment is better than surgery outcomes

False- drugs are used less often because they have an unpredictable effect due to pts metabolizing drugs differently

MOA of Cholinesterase Inhibitors in tx. of ETs

Echothiophate iodine (Phospholine Iodide) and Isoflurophate

-increase ciliary body sensitivity to Ach.

-Allows the eye to accommodate with w/ less Ach.

-Decreased accommodative effort reduces the amount of

accommodative convergence (reduces the AC/A)

- Drugs administered as an ointment or a solution at a

loading dose and then tapered over time

- May cause extreme sensitivity to muscle relaxants (general anesthesia) and iris cysts

- No longer used in current practice

Magnitude of residual ET =

•BO prism if patient is stable with prism

•VT to improve BI Ranges

•taper prism

Magnitude of residual ET =

•Monitor if asymptomatic

•Aggressive VT?

Magnitude of residual ET = >15Δ

Normal fusion potential = yes

What are our treatment options?

•BO prism (Fresnel) until surgery or Botox

Magnitude of residual ET = >15Δ

Normal fusion potential = no

What are our treatment options?

Surgery or Botox

when is an eso pt a poor prism candidate

if they adapt/ eat prism

would ultimately make pt more eso

when do you consider surgery for an eso

>15 ^

a ET pt decides to undergo a long VT program in the synoptophore, what other treatment could be useful during this time

full time, alternating occlusion

strabismic deterioration

angle of deviation that increases over time

recession

move EOM posteriorly on the globe to weaken pull

resection

move EOM anteriorly on globe/ shorten muscle to strengthen pull

What surgery is often used to correct ETs?

ET treated with recession

• Weaken pull of MR by moving insertion farther back on globe

ET treated with resection

• Strengthen pull of LR by moving insertion closer to limbus

-*Larger deviations may require bilateral surgery

What increases the risk of consecutive XT after surgery?

•Greatest risk for those with IOOA and amblyopia

•Onset of Consecutive XT often years after surgery

•Outcome wasn't associated with type of ET

which pts are strabismus surgery candidates?

large angle >10 ^

any direction of strab- eso, exo, hyper, hypo, torsional

comitant and incomitant

unilateral and alternating

constant and intermittent (w/ poorer control)

>6 mo

at what ages can you do strabismus surgery

>6 months

upper limit decided based on pts ability to tolerate anesthesia

EOM surgical process

•Outpatient procedure (elective)

•Done under general anesthesia

- No incisions on the eye lids or eye ball itself

- Doctor moves muscles to strengthen or weaken their pull

- The surgeon does NOT remove the eye ball

Plication

•Used to tighten muscle as alternative to resection

•Muscle body lifted off sclera and folded on top of itself to shorten muscle

•Less invasive and can be done with topical anesthesia

•May be used for small angle strab (

Adjustable Sutures

•Cut muscle leaving suture attached with knot

•Can adjust the tightness of the muscle within 24 hours

post surgically while the patient is awake

•Allows for subjective assistance from patient to help

align the eyes

•Typically reserved for adult patients

•Limited evidence this procedure improves outcomes

What to expect in terms of symptoms/ recovery after EOM surgery?

•Localized redness right after sx is common (subconj heme) but heals quickly

•Mild discomfort possible typically managed with Motrin

•Most patients can return to school or work within a few days

•Possibility of double vision following sx (usually short term)

what is the success rate of strabismus surgery

depends on how you define success

78% cosmetic (

____% surgically treated ETs decompensated 3 yrs post sx

21%

there is a higher rate of reoperation with strab surgery in __________ pts

older pts

make sure to still send your older pts to peds strab surgeon bc they do this sx all the time, not general OMD

What does the success rate of strabismus surgery depend on?

•type of strab, age, definitions of success, length of follow up, magnitude of the eye turn, and direction of eye turn.

•There's always a risk that the eye turn will come back or need another sx.

_________ pts typically have higher success rate with strab surgery

younger

Long term success rates of strabismus surgery appear to be about _____%

50%

Factors associated with better surgical outcomes

✓ Strabismus onset after 6 months of age, but still a young pt

✓ Shorter duration of strabismus before surgery

✓ normal fusional potential

✓ Smaller magnitude strabismus before surgery

✓ Purely horizontal strabismus

✓ Exotropia (not as favorable for Esotropia)

✓ No amblyopia

✓ Less post surgical residual strabismus

at the end of the day, EOM surgery is ____________

elective, not medically necessary

T/F if surgery is indicated do not delay referral to surgeon

True

Non-accommodative ET

magnitude of ET is altered by

What is non-accommodative ET? What are the 4 types?

- Early Onset

- Acute Acquired Comitant ET

- Divergence Insufficiency ET

- Consecutive

If the magnitude of the ET is altered by

non-accommodative ET

-ET is not exacerbated by accommodation

-Hyperopia and AC/A not the cause of the ET

What is the onset of early onset Non-accomm. ET?

6 mos - 5 years old

median age of diagnosis is 4 yo

2nd most common type of ETs

early onset non-accommodative ETs

Characteristics of Early onset Non-Accomm. ET

a) magnitude

b) distance vs. near deviation

c) refractive error

-Moderate angle ET (median 25Δ)

-Constant ET (rarely diplopia)

-Angle similar at distance and near

-Low hyperopia (

90% of all strabismus begins before age _________

6 yo

How do we manage Early onset Non-Accomm. ET

*usually treated w/ prism & sx.

first Rx specs for hyperopia and treat amblyopia

-

Prognosis of Early onset Non-Accomm. ET

-few achieve bifoveal fusion with high-grade stereopsis

-poorer prognosis for onset

-Chance of recurring ET or consecutive XT after surgery

Late Onset Non-Accomm ET aka

Acute Acquired Comitant ET

typical age of onset for Late Onset Non-Accomm ET

>5 yo

Characteristics of Acute Acquired Comitant ET

-Sudden onset

-moderate size (15-35Δ)

-comitant ET

-Horizontal Diplopia

-Onset >5yo

Classic (non-neurological) Etiologies of Acute Acquired Comitant ET

-Type I - Swan

-Type II - Burian-Franceschetti

-Type III - Bielschowski

**There is a non-classical but non-neurological cause = Decompensated Eso

Acute Acquired Comitant ET -Swan (Type I) Etiology

Sudden onset due to interrupted fusion (monocular occlusion or vision loss)

Acute Acquired Comitant ET -Burian-Franceschetti (Type II) Etiology

Result of physical or psychological stress causing large ET

Acute Acquired Comitant ET -Bielschowski (Type III) Etiology

associated with moderate to high myopes performing intense prolonged near work without glasses (convergence without accomm causing convergence spasm)

Acute Acquired Comitant ET - What are some Neurological Etiologies?

-Brain tumors

-Idiopathic Intercranial Hypertension

-Seizures

-Migraines

-Hydrocephalus

-Frequency of underlying neuro etiology in children is low

Acute Acquired Comitant ET- Risk Factors for Neuro Etiology

• Older children (mean age 7yo)→ adults

• Presence of Papilledema (only seen in about 1/3 of neuro etiology)

• Larger ET at distance

• Nystagmus (Chiari malformations, hydrocephalus, tumors)

• Inability to provide fusion with plus and/or prism

Non-Classic (non-neurological) Etiologies of Acute Acquired Comitant ET

decompensated eso (15-45^)

could be due to smartphones? due to high accommodation and short working distance

Studies have shown that smartphone usage can cause Acute Acquired Comitant Esotropia. What patients are at risk of this?

• ≥6 hours/day on smart devices (tablets/smartphones)

• Short working distances (20cm)

• Patients of all ages (predominantly teens to young adults)

• Myopic presbyopes who remove glasses to read

• Myopes may be higher risk, but all refractive errors represented