The common causes of V-pattern are:
- Over-action of the inferior muscles (10 or IR)
- Under-action of the superior muscles (SO or SR)
- Over-action of medial rectus
- Brown syndrome
The common causes of A-pattern are:
- Over-action of the superior muscles (SO or SR)
- Under-action of the inferior muscles (10 or IR)
- Under-action of lateral rectus