Consecutive Exotropia (XT) Flashcards
What is a consecutive exotropia?
An exotropia occurring in a patient with a history of esotropia.
How might consecutive esotropia present?
1) Spontaneously
Occurs for unknown, or known, reasons e.g. sudden visual loss
2) Post-Operatively
In the initial post op period planned or unplanned (early)
Or
May present as adults years after original surgery (late)
What must you consider in Early Post-Op Consecutive XT?
1) Was it planned or unplanned?
2) Were there complications during surgery?
3) What are the symptoms?
4) What is the appearance of the XT?
5) What are the clinical features?
Why might we want to overcorrect an ET?
If the patient has a tendency to move in we may want to overcorrect to ET if they the risk of diplopia during PODT and have diplopia at straight or slightly ET
So due to risk of symptoms when correcting
When might we suspect a detached muscle post-surgery?
The eyes wont move in at the angle expected during OMs i.e. restricted. We suspect detachments as they may have rubbed their eye or the suture may not have been tight enough
What do we do if we suspect a detached muscle post-surgery?
Go back in and reattach but it can be hard to find as “pinged back” into the orbit. Can do a CT scan of the orbit to see the position of the muscle.
What do we do when we don’t suspect a detached muscle?
If it’s not detached it could lead to scar tissue which would need to be observed + non-surgical management or surgical intervention
What are the non-surgical interventions when we don’t expect a detached muscle but the OM’s aren’t moving properly post-surgery?
Optical - reduce hypermetropic correction / increase myopic correction
Prisms - Restore BSV / alleviate diplopia
BT Injection
What are the surgical interventions when we don’t expect a detached muscle but the OM’s aren’t moving properly post-surgery?
Concerns over symptoms/appearance so do surgery
What might slipped, severed, torn or lost extraocular muscles look like?
- Widening of palpebral fissures
- Limited ductions
- Reduced saccadic velocities (we look for smooth pursuit to get ppt to look at one point and then another without moving their head)
- Differential changes in IOP
What did Heaven & Anson’s (1995) found out about the long-term results of surgery for consecutive and secondary XT?
Amblyopic ET are at a higher risk of becoming consecutive XT after surgery
Large angle the older the presentation the larger the angle mean 45∆ (range 10-90∆)
Adduction limited in one or both eyes 92%
Amblyopia in 58%
Alphabet pattern 44%
Hypermetropia 25%
Diplopia 25%
What did Gesite-de Leon & Demer (2014) find out about consecutive XT?
Those with consecutive XT have significant late exodrift post-surgery. At 1.6 years follouw-up 50% remained within 10PD orthotropia but 50% recurrent XT of 25PD
Pre-Operatively:
- PCT (mean, 28Δ),(range, 12Δ–60Δ)
- Medial rectus slippage of 2.5mm (range, 1.0–5.0 mm)
- MR slippage in 14 patients (36%) who had previously undergone medial rectus recession.
Post-Operatively:
- PCT (mean 2Δesotropia)
- Significant late exodrift, averaging 17Δat final follow-up.
- At final follow-up, 1.6 (range, 0.10–6.2) years after surgery - 50% of patients maintained alignment within 10Δof orthotropia (mean, 3Δ± 4Δexotropia); the rest experienced recurrent exotropia of 25Δ.
What is the aim of non-surgical management of consecutive XT’s?
To alleviate diplopia –> restore BSV, or establish suppression zone
What’s the aim of surgical management in consecutive XT’s?
- To achieve a post operative overcorrection of 5-10∆
- Improve any adduction deficit
What are the options in surgical management of small-angle consecutive XT’s?
Small angles single muscle surgery may be sufficient
