Isolated medial rectus is a rare clinical entity. This prospective study of 32 patients from China showed that this was caused most commonly by iatrogenic injury (43.75%), trauma (37.50%) and congenital (18.75%) causes. An average of 60 ±25 prism dioptres (PD) was significantly reduced to 12 ±13PD. An angle <10PD was achieved in 62.50% of patients. Twenty-eight patients had one surgery, three patients had two surgeries and one patient had three surgeries. Surgical choice was a combination of medial rectus repair, medial rectus recession, lateral rectus resection, vertical muscle transposition and orbital wall suture depending on medial rectus function and forced duction testing. The authors report their limitations being a small sample size, a possible bias in that all the patients required surgery and it focused solely on medial rectus palsy therefore cannot be extrapolated to cases where more than this muscle is involved. This is a large study of a rare clinical problem. It provides evidence on possible surgical management of these cases and is the largest of its kind.