9 - Exodeviations Flashcards
FdR d’exotropie
Risk factors for exotropia include
* Maternal substance abuse
* Smoking during pregnancy
* Premature birth
* Perinatal morbidity
* Genetic anomalies
* Family history of strabismus
* Uncorrected refractive errors
(Pseudoexotropia)
Définir la Pseudoexotropie
The term pseudoexotropia refers to an appearance of exodeviation when in fact the eyes are properly aligned.
(Pseudoexotropia)
Prévalence de la Pseudoexotropia?
Pseudoexotropia is much less common than pseudoesotropia
(Pseudoexotropia)
Causes/Exemples de Pseudoexotropia (x2)?
May occur when there is a wide interpupillary distance or a positive angle kappa with or without other ocular abnormalities
(Exophoria)
Définir l’Exophorie
Exophoria is an exodeviation controlled by fusion under normal binocular viewing conditions.
(Exophoria)
Comment détecter l’Exophorie?
An exophoria is detected when binocular vision is interrupted, as during an alternate cover test or monocular visual acuity testing.
(Exophoria)
Prévalence de l’Exophorie?
Exophoria is relatively common
(Exophoria)
L’Exophorie est-elle symptomatique ou asymptomatique généralement?
Patients are usually asymptomatic, although with prolonged near work, they may experience asthenopia.
(Exophoria)
Exemple de précipitants qui causent une décompensation de l’Exophorie en Exotropie?
Decompensation of an exophoria to an exotropia may occur when the patient is ill or under the influence of sedatives or alcohol.
(Exophoria)
Est-il recommandé de traiter l’exophorie?
Treatment is recommended when an exophoria becomes symptomatic
Quel est le type de manifest exodeviation le plus fréquent?
Intermittent exotropia is the most common type of manifest exodeviation.
(Intermittent exotropia)
Vers quel âge se manifeste l’exotropie Intermittente ?
The onset of intermittent exotropia is usually before age 5 years, and the exotropia typically continues into adulthood.
(Intermittent exotropia)
Circonstances où l’Intermittent exotropia devient manifeste?
The exodeviation becomes manifest during times of
* Visual inattention
* Fatigue
* Stress
* Illness
* Exposure to bright light
Parents of affected children often report that the exotropia occurs late in the day or when the child is daydreaming or tired.
(Intermittent exotropia)
Impact de la lumière sur l’Intermittent exotropia?
Exposure to bright light often causes exodeviation and a reflex closure of 1 eye (which is why strabismus is sometimes referred to as a “squint”).
(Intermittent exotropia)
Exodéviation est-elle plus prononcée lors VP ou VL?
Exodeviations are usually larger when the patient views distant targets, and they may be difficult to elicit at near.
(Intermittent exotropia)
Autres signes/éléments associés à l’Intermittent exotropia
Intermittent exotropia can be associated with small hypertropias, A and V patterns (see Chapter 10), and overelevation and underelevation in adduction (see Chapter 11).
(Intermittent exotropia)
Évolution de l’Intermittent exotropia si non traitée?
Left untreated, intermittent exotropia may remain stable, resolve, or progress, sometimes to constant exotropia.
(Intermittent exotropia)
Est-ce que la diplopie chez les patients avec intermittent exotropia est fréquente?
Because of suppression, children younger than 10 years with intermittent exotropia rarely report diplopia.
(Intermittent exotropia)
Est-ce que les enfants avec Intermittent exotropia maintiennent une bonne fonction binoculaire?
- They retain normal retinal correspondence and good binocular function when orthotropic.
- Amblyopia may occur if the strabismus is poorly controlled or becomes constant.
(Intermittent exotropia)
Catégorisation du contrôle de l’Intermittent exotropia
Exodeviation control may be categorized as follows:
* Good control: Exotropia manifests only after cover testing, and the patient resumes fusion rapidly without blinking or refixating.
* Fair control: Exotropia manifests after fusion is disrupted by cover testing, and the patient resumes fusion only after blinking or refixating.
* Poor control: Exotropia manifests spontaneously and may remain manifest for an extended time.
Some ophthalmologists use the Newcastle Control Score for Intermittent Exotropia to quantitatively grade the control exhibited by patients with this deviation.
(Intermittent exotropia)
Qu’est-ce que le Newcastle Control Score for Intermittent Exotropia?
- Pour l’évaluation de l’Exodeviation control
- Le score incorporate data from both the clinic visit and from symptoms experienced at home and are scored from 0 to 9, with 9 being the worst control.
Pour quel type de déviation oculaire utilise-t-on le Newcastle Control Score?
For Intermittent Exotropia
(Intermittent exotropia)
Concernant l’Intermittent exotropia, quel test est-il préférable de faire en premier à l’e/o et pourquoi?
Because visual acuity and alignment tests are dissociating and may adversely affect assessment of strabismus control, they should be performed after sensory tests for stereopsis and fusion.
(Intermittent exotropia)
Pour l’intermittent exotropia, la déviation est-elle plus grande lors de la fixation de près ou de loin ? Pourquoi?
- The deviation at near fixation is often smaller than the deviation at distance fixation.
- This difference is usually due to tenacious proximal fusion, a slow- to- dissipate fusion mechanism at near.
- The difference may sometimes be due to a high accommodative convergence/accommodation (AC/A) ratio, but a high AC/A ratio occurs much less commonly in exotropia than in esotropia
(Intermittent exotropia)
Que signifie basic intermittent exotropia
The exodeviation is termed basic intermittent exotropia when the size of the deviation at distance fixation is within 10 prism diopters (D) of the deviation size at near fixation.
(Intermittent exotropia)
V ou F : No children have a larger deviation at near than at distance in Intermittent exotropia
Faux. Some children have a larger deviation at near than at distance; this is distinct from convergence insufficiency.
(Intermittent exotropia)
Que faire si on mesure une exodéviation at distance qui est > 10D de celle at near fixation dans l’Intermittent exotropia?
- When the exodeviation at distance is larger than the deviation at near fixation by 10D or more, the near exodeviation should be remeasured after 1 eye is occluded for 30–60 minutes (the patch test).
- The patch test eliminates the effects of tenacious proximal fusion, helping distinguish between pseudodivergence excess and true divergence excess.
- A patient with pseudodivergence excess has similar distance and near measurements after the patch test.
- A patient with true divergence excess continues to have a significantly larger exodeviation at distance.
Many patients with true divergence excess also have a high AC/A ratio.
* For these patients, the AC/A ratio can be determined by measuring the near deviation with and without +3.00 diopter (D) lenses (while the patient wears corrective lenses, if necessary), after the patch test is completed. The measurements are then compared.
* Alternatively, the distance deviation can be measured with and without −2.00 D lenses to determine the AC/A ratio.
(Intermittent exotropia)
Différence entre le pseudodivergence excess et le true divergence excess dans l’évalutation de l’Intermittent exotropia post-patch test de 30-60 minutes?
- A patient with pseudodivergence excess has similar distance and near measurements after the patch test.
- A patient with true divergence excess continues to have a significantly larger exodeviation at distance.
Many patients with true divergence excess also have a high AC/A ratio.
* For these patients, the AC/A ratio can be determined by measuring the near deviation with and without +3.00 diopter (D) lenses (while the patient wears corrective lenses, if necessary), after the patch test is completed. The measurements are then compared.
* Alternatively, the distance deviation can be measured with and without −2.00 D lenses to determine the AC/A ratio.
(Intermittent exotropia)
Quel type de patients pourrait être seulement observé/monitoré dans le Intermittent exotropia?
- All patients with exodeviations should be monitored as some will require treatment.
- Patients who have well- controlled, asymptomatic intermittent exotropia and good binocular fusion can be observed.
- Untreated strabismus often results in poor self- esteem in adults and children.
- Adults with strabismus report a wide range of difficulties with social interactions, which improve significantly after surgery.
(Intermittent exotropia)
3 options de Nonsurgical management dans l’Intermittent exotropia
- Correction of refractive errors (hyperopia > 4,00D, toute myopie, on peut même sur corriger de 2,00-2,00D)
- Oclusion therapy (même sans amblyopie)
- Prisms: Although they can be used to promote fusion in intermittent exotropia, base-in prisms are seldom chosen for long- term management because they can cause a reduction in fusional vergence amplitudes.
(Intermittent exotropia)
Dans le traitement de l’Intermittent exotropia :
* Pertinence de la correction de l’erreur réfractive (myopie, hypermétropie)?
* Pertinence de l’overcorrection?
- Corrective lenses should be prescribed for significant refractive errors.
- Correction of even mild myopia may improve control of the exodeviation.
- In some cases, overcorrection of myopia by 2.00–4.00 D can stimulate accommodative convergence to help control the exodeviation. This therapy may cause asthenopia in school- aged children.
- For patients whose initial overcorrection results in control, the prescription can be gradually tapered and surgery may be avoided.
- Mild- to- moderate degrees of hyperopia are not routinely corrected in children with intermittent exotropia because refractive correction may worsen the deviation.
- Children with marked hyperopia (>+4.00 D) may be unable to sustain accommodation, which results in a blurred retinal image and manifest exotropia. In these patients, correction of refractive errors with glasses or contacts may improve retinal image clarity and help control the exodeviation.
(Intermittent exotropia)
Pertinence de l’occlusion therapy dans le Tx de l’Intermittent exotropia?
- Occlusion therapy (patching) for amblyopia may improve exotropic deviations.
- For patients without amblyopia, part- time patching of the dominant (nondeviating) eye or alternate patching (alternating which eye is patched each day) in the absence of a strong ocular preference can improve control of small- to moderate- sized deviations, particularly in young children.
- The improvement is often temporary, however, and many patients eventually require surgery.
(Intermittent exotropia)
Pertinence des prismes dans le Tx de l’Intermittent exotropia?
Although they can be used to promote fusion in intermittent exotropia, base-in prisms are seldom chosen for long- term management because they can cause a reduction in fusional vergence amplitudes.
DONC : Pas un bon choix comme Tx à long terme.
(Intermittent exotropia)
Facteurs influençants la décision d’un surgical treatment pour l’Intermittent exotropia (x6).
Factors influencing the decision to proceed with surgery include strabismus that is
* frequently manifest
* poorly controlled
* worsening (especially at near)
* symptomatic
* poor self- image
* difficulty with personal or professional relationships.
(Intermittent exotropia)
Types de chirurgie proposés pour l’Intermittent exotropia
Surgical treatment of exotropia typically consists of
* bilateral lateral rectus muscle recession or
* unilateral lateral rectus muscle recession combined with medial rectus muscle resection.
Large (>50D) deviations may require surgery on 3 or 4 muscles.
For small deviations, single- muscle recession is sometimes performed.
The optimal age for surgery and the choice of procedure are debatable.
Caution is advised when surgery is considered for patients with true divergence excess exotropia, as they are at risk for postoperative diplopia and esotropia at near.
(Intermittent exotropia)
Concernant le postoperative alignment in Intermittent exotropia :
* Taux de récurrence selon les long-term follow-up studies?
* Résolution spontanée ou non d’un small-angle esotropia dans les PO immédiat?
* Sx possible en PO?
* Indications de traiter l’ésotropie?
* Délai avant seconde opération dans un contexte ésotropie PO?
* Tx additionnel pour patient avec un true divergence excess
- Long- term follow-up studies of the effectiveness of surgical treatment of intermittent exotropia show high recurrence rates.
- Patients may require multiple surgeries to maintain ocular alignment long term.
- A small- angle esotropia in the immediate postoperative period tends to resolve and is desirable because of its association with a reduced risk of recurrent exotropia.
- Patients may experience diplopia while esotropic.
- An esodeviation that persists beyond 3–4 weeks or that develops 1–2 months after surgery (postsurgical esotropia) may need further treatment (hyperopic correction, base- out prisms, patching to prevent amblyopia, or additional surgery).
- Unless deficient ductions suggest a slipped or “lost” muscle, a delay of a few months is recommended before reoperation for postsurgical esotropia, as spontaneous improvement may occur.
- Bifocal glasses can be used for a high AC/A ratio and should be discussed preoperatively with patients who have true divergence excess.
(Convergence Insufficiency)
Définir le Convergence Insufficiency.
- Convergence insufficiency (CI) is an exodeviation that is greater at near fixation than at distance fixation.
- It is characterized by poor fusional convergence amplitudes and a remote near point of convergence
(Convergence Insufficiency)
Sx de Convergence Insufficiency
This sometimes results in symptoms of asthenopia, blurred near vision, and diplopia during near work, usually in older children or adults.
Rarely, accommodative spasms occur when accommodation and convergence are stimulated in an effort to overcome the CI.
(Convergence Insufficiency)
Convergence Insufficiency est une complication fréquente d’une mx neurodégénérative, laquelle?
Convergence insufficiency is a common complication of Parkinson disease.
(Convergence Insufficiency)
Traitement médical et chirurgical du Convergence Insufficiency
- Treatment of symptomatic CI typically involves orthoptic exercises.
- Base- out prisms can be used to stimulate and strengthen fusional convergence amplitudes.
- Stereograms, “pencil push- ups,” and computer- based or office- based convergence training programs are all viable options.
- If these exercises fail, base-in prism reading glasses may alleviate symptoms.
- Surgical treatment, usually medial rectus muscle resection, may be indicated in patients whose problems persist despite medical therapy.
(Constant exotropia)
Étiologies/Causes de Constant exotropia
- Constant exotropia is encountered most often in older patients with sensory exotropia or in patients with a history of long- standing intermittent exotropia, which has decompensated.
- Constant exotropia also occurs in persons with infantile or consecutive exotropia.
Lequel survient dans le Constant exotropia versus le Intermittent exotropia :
* Pseudodivergence excess
* True divergence excess exotropia
Les deux peuvent survenir pour les exotropies intermittente et constante.
A patient with an exotropia that is constant can have basic, pseudodivergence excess, or true divergence excess exotropia— the same forms seen in intermittent exotropia.
(Constant exotropia)
Traitement chirurgical
Surgical treatment is the same as that for intermittent exotropia.
Surgical treatment of exotropia typically consists of
* bilateral lateral rectus muscle recession or
* unilateral lateral rectus muscle recession combined with medial rectus muscle resection.
Large (>50D) deviations may require surgery on 3 or 4 muscles.
For small deviations, single- muscle recession is sometimes performed.
The optimal age for surgery and the choice of procedure are debatable.
Caution is advised when surgery is considered for patients with true divergence excess exotropia, as they are at risk for postoperative diplopia and esotropia at near.
(Constant exotropia)
Pourquoi ces patients peuvent se plaindre d’une réduction du champs de vision en PO ?
Some patients with constant exotropia have an enlarged field of peripheral vision because they have large areas of nonoverlapping visual fields.
These patients may notice a field constriction when the eyes are straightened.
(Infantile Exotropia)
Lequel est le plus prévalent entre Esotropie et Exotropie Infantile?
Infantile exotropia is much less common than infantile esotropia.
(Infantile Exotropia)
Age of onset of Infantile Exotropia
Constant infantile exotropia is apparent before age 6 months as a large- angle deviation (Fig 9-1).
(Infantile Exotropia)
Lequel est le plus à risque d’amblyopie : constant ou intermittent exotropia?
The risk of amblyopia is higher in constant exotropia than in intermittent exotropia.
(Infantile Exotropia)
Les enfants avec constant exotropia sont plus à risque de quels disorders?
Although infants with constant exotropia may be other wise healthy, the risk of associated neurologic impairment or craniofacial disorders is increased in these patients.
* A careful developmental history is thus important, and referral for neurologic assessment should be considered if there are indications of developmental delay.
(Infantile Exotropia)
Concernant le Tx chirurgical de l’Infantile Exotropia :
* À quel âge l’enfant est-il opéré?
* Outcomes de l’opération?
* Restauration de la fonctione binoculaire?
- Patients with constant infantile exotropia are operated on early in life, and outcomes are similar to those for infantile esotropia.
- Early surgery can lead to monofixation with gross binocular vision, but restoration of normal binocular function is rare.
- Dissociated vertical deviations and overelevation in adduction may develop
Consecutive exotropia
Définir le Consecutive exotropia
Exotropia that occurs after a period of esotropia is called consecutive exotropia.
* Rarely, exotropia may develop spontaneously in a patient who was previously esotropic and never underwent strabismus surgery.
* Much more commonly, consecutive exotropia develops after previous surgery for esotropia (postsurgical exotropia)
Consecutive exotropia
Combien de temps après une chirurgie pour ésotropie on peut s’attendre à développer une consecutive exotropia ?
Usually within a few months or years after the initial surgery.
However, in some patients who had surgery for infantile esotropia, consecutive exotropia may not develop until adulthood.
Consecutive exotropia
Constante ou intermittente ?
Un ou l’autre
Consecutive exotropia
Définir sensory exotropia
Esotropia or exotropia may develop as a result of any condition that severely reduces vision or the visual field in 1 eye.
Consecutive exotropia
Pourquoi certains patients développent une ésotropie alors que d’autres une exotropie?
It is not known why some individuals become esotropic and others exotropic after unilateral vision loss.
En général:
< 4 ans = ET
> 4 ans = XT
Sensory Exotropia
Quelle population est plus à risque ?
Enfants plus âgés et adultes
In addition, although both sensory esotropia and sensory exotropia occur in infants and young children, the latter predominates in older children and adults
Sensory exotropia
Dans quel cas est-ce qu’on peut s’attendre à une diplopie constante et permanente chez ces patients ? Par quoi est-ce causé ?
Loss of fusional abilities, known as central fusion disruption, can lead to constant and permanent diplopia despite anatomical realignment when adult- onset sensory exotropia has been present for several years before vision rehabilitation.
Sensory Exotropia
Est-ce que la fusion périphérique peut être rétablie en PO ?
Oui.
If the vision in the exotropic eye can be improved, peripheral fusion may be reestablished after surgical realignment, provided the sensory exotropia has not been present for an extended period.
Duane retraction syndrome
Quel type (1,2,3) de syndrome de Duane est associé à une exotropie et quels sont les 2 autres signes fréquemment associés à l’exo ?
Patients with type 2 can present with exotropia, usually accompanied by deficient adduction and a head turn away from the affected side.
Nomme 3 étiologies neuromusculaires d’exotropie
A constant exotropia may result from
* third nerve palsy
* internuclear ophthalmoplegia (INO)
* myasthenia gravis
DHD
Que signifie l’abbréviation DHD?
Dissociated horizontal deviation (DHD)
DHD
Quel est le signe qui suggère un dx de dissociated horizontal deviation plutot qu’une vraie exophorie ?
When a dissociated abduction movement is predominant, the condition is called dissociated horizontal deviation (DHD). Though not a true exotropia, DHD can be confused with a constant or intermittent exotropia.
- Dissociated vertical deviation and latent nystagmus often coexist with DHD.
- In rare cases, patients may manifest both DHD and intermittent esotropia.
DHD
Tx chirurgical du DHD
Treatment of DHD usually consists of unilateral or bilateral lateral rectus recession in addition to any necessary oblique or vertical muscle surgery
convergence paralysis
Où est situé la lésion intra-crânienne souvent associé au dx de convergence paralysis ?
Convergence paralysis is distinct from convergence insufficiency and usually secondary to an intracranial lesion, most commonly in association with dorsal midbrain syndrome (mésencéphale dorsal)
convergence paralysis
Caractéristiques du convergence paralysis ?
It is characterized by normal adduction and accommodation, with exotropia and diplopia present at attempted near fixation only.
convergence paralysis
Comment peut-on distinguer une convergence paralysis vs malingering ?
Apparent convergence paralysis due to malingering or lack of effort can be distinguished from true convergence paralysis by the absence of pupillary constriction with attempted near fixation.
convergence paralysis
Quel est le traitement du convergence paralysis ?
Treatment of convergence paralysis is difficult and often limited to use of base-in prisms at near to alleviate the diplopia.
* Plus lenses may be required if accommodation is limited.
* Monocular occlusion is indicated if diplopia cannot be other wise treated.
DHD
Comment on peut distinguer DHD vs anisohyperopia associated with intermittent exotropia ?
DHD must be differentiated from anisohyperopia associated with intermittent exotropia, in which the exotropic deviation is present during fixation with the normal eye but is masked during fixation with the hyperopic eye because of accommodative convergence.
DHD
Traitement du DHD
Treatment of DHD usually consists of unilateral or bilateral lateral rectus recession in addition to any necessary oblique or vertical muscle surgery.
