A & V patterns 3

Question 1

RAD SIN

Answer 1

Vertical Rectus muscle ADduct

Superior muscles INtort

Question 2

5∆BO on elevation, 15∆BO in PP, 35∆BO in depression

Answer 2

V ESO

Greatest deviation is in depression, more convergent looking down than looking up

Question 3

5∆BI on elevation, 18∆BI in PP, 25∆BI on depression

Answer 3

A EXO
More divergent looking down so A exo, more convergent in elevation

Question 4

V pattern can be caused by IO over action and SR underaction

Answer 4

IO= an abductor so an overaction- more divergence looking up.
SR= an adductor so an underaction- less adduction and more abduction and SO underactor- less abduction looking down (-= abductors, +=adductors)

Question 5

A pattern possible cause-which u/a and o/a muscles

Answer 5

SR overaction and IR underaction. A pattern has more abduction in elevation, overaction of SO (abductor) more divergence and IR underaction with IO underactor

Question 6

V ESO more convergent where and which muscles overacting

Answer 6

overaction of MR and is more convergent looking down

Question 7

What does MR insertion too high cause

Answer 7

causes V pattern. Insertion is too high, so the muscle in elevation becomes more slack so less adduction, MR is an adductor, less elevation in adduction

Question 8

LR insertion too low

Answer 8

causes V pattern as LR is abductor and there is more slack on downgaze, less abduction, more adduction in LR depression

Question 9

Oblique muscle positioned too anterior leads to which alphabet pattern

Answer 9

The abducting force of SO is weakened an lead to a V eso

Question 10

Saggitalisation of SO

Answer 10

The angle between the SO and visual angle is reduced compared to angle for IO, and leads to SO and SR contract to compensate for the torsion and causes SO over-action and A pattern

Question 11

Saggitalisation

Answer 11

It is muscle is closer to the anterior/posterior axis of the globe
- look at the inferior oblique and So to see which muscles are contracting to compensate

Question 12

Saggitalisation of SO

Answer 12

• Superior muscles are contracting so overacting SO and SR overactions- which gives an A pattern

Question 13

Saggitalisation of IO

Answer 13

Inferior muscles (IO and IR) are contracting so overactions of this causes a V pattern

Question 14

Surgery for V pattern

Answer 14

Anterior transposition of IO
IO position more anterior- weakening so anterior transposition will weaken and less abduction so close V

Question 15

Surgery for A pattern

Answer 15

SO tenotomy
SO Overacting in A- tenotomy weakens the SO- Transpose LR upwards will cause less divergence on elevation and increase the a pattern and increased abduction on depression

Question 16

Surgery of V eso

Answer 16

Bilateral MR recessions and IO myectomy
Correct eso deviation- weaken medial recti then IO is overacting in A pattern so IO is weakened in a myectomy

Question 17

Surgery for A exo

Answer 17

LR recess/MR resect and SO tendon spacer
SO tendon spacer- spacer between tendon so making it longer and weakening the SO to close the A

Question 18

Case 1- History
—24 year old patient presents with asthenopic symptoms

Bilateral LR recession (5mm) for XT aged 15 years
Bilateral MR resection (5mm) inferior displacement of each MR for XT with associated A pattern aged 20 years

Present prescription
R -8.00/+2.25x96
L -7.00/+1.75x94

VA R 0.1 L 0.1
CT cgls N sl/mod intermittent XT c brief control
cgls sl D intermittent XT
OM A exo more abduction in down gaze

—Worth lights cgls N&D BSV
Titmus test cgls 100 sec of arc
PCT N and D 18∆BI

Answer 18

Aetiology- MR was moved down, MR more slack looking down so more abduction looking down A pattern is worse and SO OA makes it larger

Question 18

2BO elevation
10BI PP
40BI depression

Answer 18

A exo
Management- LR recess and MR resection with SO tenotomy

Question 19

5 year old boy. Parents noticed esotropia from approximately 1 year of age
Angle of deviation has increased and noticed all the time now, parents are keen for treatment
No refractive error

VA R 0.3 L 0.0 Crowded logMAR
CT N & D mod RET
Bagolini gls N & D Right suppression response
Synoptophore Objective: +15 degrees Subjective: right suppression (peripheral slides)

PCT N + D 30 BO

Answer 19

Aetiology- IO overaction and SR underaction

Expected anomaly- IO overaction and SR underaction

Question 20

20 BO elevation
30 BO PP
40 BO depression

Answer 20

V eso
Management- MR recession and IO myectomy/myotomy or IO recession or Anterior transposition

Question 21

30 year old female is unhappy with appearance of strabismus and keen for surgery.
5’2 tall, prev surgery for convergent strabismus and patching treatment as a child.
Refractive error:
R -0.50/+0.25*80 L -2.50DS
VA cgls R 0.16 L -0.04 l
CT c and sgls
N sl/mod RXT
D mod RXT
OM- V exo

Answer 21

V ESO
Expected anomaly IO overaction and SO underaction

Question 22

Surgical options

Answer 22

Bilateral LR recession and IO myotomy/myectomy or recession work on the IO muscle for the V Pattern
Bilateral IO weakening

Question 23

Alphabet patterns

Answer 23

Tend to operate on both muscles

Question 24

TO KNOW

Answer 24

Define patterns
Know aetiological factors
Diagnosing patterns
Surgical management options