Heterophoria mangement Flashcards
which 2 types of patients with heterophoria are appropriate to treat
- Symptomatic patients
- Asymptomatic and decompensating (under 8 yrs old)
why must you immediately treat an asymptomatic and descompensating heterophoria patient under the age of 8
they can end up with a constant tropia and can develop amblyopia and suppression
if they develop suppression, they won’t have any stereo vision and will struggle with driving, writing etc
what 4 things does a complete full investigation consist of prior to deciding to treat a patient with symptomatic heterophoria
- Diagnosis understood
- Full BV work up
- Fundus exam
- Post refraction (cyclo for children)
why must a full BV work up be investigated before treating someone with a heterophoria
if your going to manage with prisms, then you must be sure of the diagnosis and that your not making something worse underneath
which 3 things can help determine if someones symptoms are truly related to a phoria
- From the history
Convergence weakness XOP symptoms >near - Diagnostic occlusion
Do symptoms stop after monocular occlusion?
suggests heterophoria is decompensating - Diagnostic prisms
Do symptoms stop after corrected
suggests heterophoria is decompensating
list 6 clinical signs and symptoms that can indicate decompensation
- Increase in symptoms
- Increase in size of phoria
speed of recovery reducing - Reduced fusional reserves
- Reduced binocular controlled acuity
- Reduced convergence
- Reduced stereo-acuity
what are the 2 types of conservative treatment methods of a decompensating heterophoria
- optical
- orthoptic exercises
what are the 2 types of optical treatment methods to treat a decompensating heterophoria
- Manipulation of Rx
- Prisms
Fresnel
incorporated
how will you manipulate an Rx for someone in order to reduce an esophoria and an exophoria and what does this Rx actually manipulate
Esophoria = +ve/convex lenses
Exophoria = -ve/concave lenses
manipulates accommodative convergence
what is the advantage of a fresnel prism
it is cheaper than having prisms incorporated and you can use them if you know the problem will get better before buying expensive incorporated lenses
so is good as a temporary measure
what is the non conservative treatment method of a decompensating heterophoria
surgery
done as a last resort
name 3 reasons that prisms are used for
- For diplopia
Give minimum horizontal correction
Often need full vertical correction - To alleviate symptoms
- Prevent decompensation
how much prism should you give for horizontal diplopia
the minimal horizontal correction
how much prism should you give for vertical diplopia
often full vertical correction
what should you try first before prescribing prisms
try exercises if possible
what are prisms only good for
they are a crutch
so just stops the symptoms but does not resolve the problem of a decompensating phoria
which type of prisms can be used for a critical period/recent onset nerve palsy
fresnel temporary prisms
what can prisms be used with if the deviation is too large
with the exercises
how should the prism be used if correcting the symptoms of a heterophoria
prism base always OPPOSITE TO DEVIATION.
why must you give minimal possible prism for horizontal phorias
due to prism adaptation
as you get older, the teamwork of both eyes gets worse and if prisms are given at a young age, then you need to keep giving stronger prism powers as the patient gets older
what are the 2 risks of prism usage
- prism adaptation
- aetiology unknown could mask ocular or systemic pathology
list 4 reasons when you will decide to give long term use of prisms
- Elderly or poor general health
- Small symptom producing vertical deviation (as we have a tiny amount of fusional reserves)
- Refusal or unfit for surgery and exercises don’t work
- Failed to respond to other forms of treatment
list 6 types of patients who will make a good selection for orthophoric exercises
- Good potential for BSV
- V-A quite good in either eye
- Motivated
- Understands exercises i.e. can’t give to a 3/5 yr old child
- Sufficient time
- Good GH
list the steps of how you will use a prim bar as an exercise to control a deviation e.g. RSOT to a phoria
- Fuse images with prism (lend prism bar or Fresnel’s)
- example RSOT
- first correct with base out prism
- Once corrected reduce prism strength while patient maintains BSV (nil diplopia), ask if they can still hold the image as one
- Now use exercising prism base in (for ESOT) = same direction as deviation
and if the RSOT is due to convergence excess (i.e. at near the ESOT is getting worse)
- Find the point of intersection (where they hold eyes straight) of visual axes by changing distance you hold fixation object
- Now increase or decrease distance your holding the target at while asking them to maintain BSV (nil diplopia)
i.e. to make the eyes straight, pull the target back until the eyes are straight and then bring the target closer and see if the px can hold their eyes straight
how can exercises to control a deviation to a phoria be used by manipulating accommodation
by:
- Stimulating exophorias (Then reducing)
- Relaxing it in esophorias (Then reducing)
in order to relax accommodation, ask the patient to make the target more blurry and therefore relax the eyes = eyes should start to turn out and if they can do that, then ask them to make the target clearer again
what will an improvement of relative convergence/change in accommodation result in
a pre-determined change in accommodative convergence
if accommodation is constant, what will happen to relative convergence as a result
relative convergence can be exerted or relaxed whilst maintaining static accommodation
for every dioptre of accommodation how many dioptres of accommodative convergence will occur
5 dioptres of accommodative convergence occurs
AC/A = 5:1
what occurs in +ve relative convergence
Convergence is exerted in excess of accommodation
i.e. going to converge more than what we can accommodate
Relative convergence controls deviation whilst static accommodation keeps vision clear
you look infront of the target in order to see it clearly
which type of heterophoria does +ve relative convergence exercises improve
exophorias
as we want them to converge more
what occurs in -ve relative convergence
Convergence is relaxed relative to accommodation
Sufficient accommodation for clear vision without the associated convergence
you look behind the target in order to see it clearly
which type of heterophoria does -ve relative convergence exercises improve
esophorias
as we want them to converge less
where is the plane of vergence in relation to the plane of accommodation in +ve relative convergence exercises
plane of vergence is infront of the plane of accommodation
where is the plane of vergence in relation to the plane of accommodation in -ve relative convergence exercises
plane of vergence is behind the plane of accommodation
with relative convergence excerices, what do you want to keep constant and what do you want to change
- Keep plane of accommodation constant
- Change stimulus to converge
what 3 things can be used for relative convergence exercises
- prism bar
- prism flippers
- stereograms
which prisms are used for +ve relative convergence exercises
base OUT
which causes px to converge
which prisms are used for -ve relative convergence exercises
base IN
which reduces convergence
explain how the stereogram method is used
- Each cat is incomplete in some way
- Card held at approx. 33cms
- Patient either fixates on:
A pencil in front of the card (positive relative convergence)
A distance object behind/through the card (negative relative convergence) - Position of the pencil changed until 3 figures are seen
- Patient asked to maintain fusion while exerting accommodation for the appropriate distance to see clearly
how frequently are patients advised to carry out exercises
Exercise for short periods frequently
Repeat each exercise once or twice 5 to 7 times daily
warn may have worsening of symptoms initially
how often should you review a patient who is carrying out exercises
every 6 weeks
what must you monitor a patient for who is carrying out exercises and when must you stop exercises
Monitor for spasm
if after exercises the px experiences constant diplopia that will not resolve then STOP
what are the 2 risks of orthophoric exercises
- intractable diplopia
- accommodative spasm (ask px to relax eyes after exercises)
which 3 reasons will you decide to refer a px for surgery
- Large angled heterophorias
- Prevention of decompensation in children
- If patient does not respond to conservative means
surgery is the last resort
which muscle mainly works at near
medial rectus
which muscle mainly works at distance
lateral rectus
what procedure weakens muscles
recession
snip muscle off from insertion and then stitch on further back
what procedure strengthens muscles
resection
snip muscle off from insertion, take a piece of it off and reattach it back to where it was originally inserted
what is the optical management for someone with a convergence excess esophoria
- Full correction hyperopia
- Minimal correction myopia
- If high AC/A ratio consider extra convex lenses
people will accept +ve at near
what is the orthoptic exercise management for someone with a convergence excess esophoria
- Increase negative base in (BI) fusional reserves (exercising divergent prisms) particularly at NEAR (where problem mainly is)
- Negative relative convergence (stereograms), as want them to converge less
which prisms will be used to manage someone with a convergence excess esophoria
Base out (BO) to relieving prism
what surgery will be done for someone with a convergence excess esophoria
Bimedial rectus recessions
what is the optical management for someone with a divergence weakness esophoria
Not suitable as:
Correction of refractive error has little effect
Extra plus will blur vision in distance
what is the orthoptic exercise management for someone with a divergence weakness esophoria
- Increase negative (BI) fusional reserves (exercising prism) particularly in the DISTANCE
- Negative relative convergence (stereograms), as want them to converge less
which prisms will be used to manage someone with a divergence weakness esophoria
Base out (BO) to relieving prism
what surgery will be done for someone with a divergence weakness esophoria
Bilateral lateral rectus resections
what is the orthophoric exercise management for someone with non-specific esophoria
- Similar management to SOP convergence excess.
- Except negative (BI) fusional amplitudes are exercised at both near and distance
what surgery will be done for someone with non-specific esophoria
medial rectus recession and lateral rectus resection
what is the optical management for someone with a divergence excess exophoria
- Full correction of any myopic error
- Consider extra minus
what is the orthophoric exercise management for someone with a divergence excess exophoria
- Increase positive (BO) fusional reserves (exercising prism) particularly in the distance
- Positive relative convergence (stereograms), to pull eyes in
which prisms will be used to manage someone with a divergence excess exophoria
Base in (BI) relieving prism
what surgery will be done for someone with divergence excess exophoria
Bilateral lateral rectus recessions
what is the optical management for someone with a convergence weakness exophoria
- Full correction of any myopic error
- Consider extra minus
what is the orthophoric exercise management for someone with a convergence weakness exophoria
- Pen convergence, dot card, jump convergence
- Increase positive (BO) fusional reserves (exercising prism) particularly at near
- Positive relative convergence (stereograms)
all respond well to convergence exercises
which prisms will be used to manage someone with a convergence weakness exophoria
Base in (BI) relieving prism
what surgery will be done for someone with convergence weakness exophoria
- Usually not required as responds well to exercises
- Bimedial medial rectus resections
what is the orthophoric exercise management for someone with non-specific exophoria
- Similar management to XOP convergence weakness.
- Except positive (BO) fusional amplitudes exercised at both near and distance
what surgery will be done for someone with non-specific exophoria
medial rectus resection and lateral rectus recession
what must you ensure with a patient who has a hyperphoria and a cyclophoria
Ensure no incomitancy
when will you treat someone with a hyperphoria
only where they are symptomatic
how will you treat someone who has a phoria with both a horizontal and vertical element
they dont respond well to exercises so instead:
1. correct vertical element only with prisms
or
2. correct vertical element with prisms and horizontal element with spheres
you try to do option 1 and treat the vertical element first as once you treat the vertical element first, they can use their horizontal fusional reserves to pull the horizontal deviation
when will you refer someone with a hyperphoria
if recent onset or longstanding & symptoms persist
how will you treat a cyclophoria
- Repeat near subjective to check cyl axis or focimeter their glasses to make sure its correct
- Difficult to treat (prisms of no value)
list the 7 circumstances that you will refer
- Any incomitancy: Urgent referral if recent onset
- Significant increase in deviation: Urgent referral
- Large angle heterophoria or failing to respond to treatment: Refer for possible surgery
- Children under 7 years old: Hospital will watch them every few weeks to make sure they don’t decompensate and end up with amblyopia and lose their binocular functions
- Unknown aetiology
- Unexplained reduced visual acuity: Urgent referral if suspicious reduction
- Anything you are unable to cope with
