Outcomes and Factors Associated with Successful Strabismus Surgery for Abducens Nerve Palsies: A Retrospective Study and Literature Review [Letter]

Dear editor

We read the article by Srimanan W recently published in Clinical Ophthalmology¹ with great interest. We really appreciate the author’s attempt to find out factors associated with the surgical success rate of abducens nerve palsy. However, we have certain concerns regarding this article that if addressed will further clarify the situation for better understanding.

The following are the concerns:

1. Preoperative forced duction test (FDT) is very important for surgical planning of abducens nerve palsy as medial rectus muscle contracture is very common after abducens nerve palsy² which may cause abduction limitation beyond the midline and might give a false impression of total abducens nerve palsy. We believe that should have been done before allocating patients to either group and surgical planning.

2. The author has correctly used the Mann–Whitney test at places with an uneven distribution of data; however, they used the mean and SD as a measure of central tendency and measure of spread respectively in representation of postoperative angles which does not seem to be normally distributed data and their representation as the median with range would have been more appropriate.

3. In the materials and methods section, treatment options discussed were unilateral medial rectus recession, monocular horizontal recession–resection, and bilateral medial rectus recession for partial abducens nerve palsy and full tendon vertical rectus muscle transposition to the lateral rectus muscle accompanied by Foster’s suture surgery for complete abducens nerve palsy cases. However, in Table 3 for subgroup analysis the author has mentioned three muscles were operated in one patient of each group. This seem to be a little confusing as it is not matching the inclusion criteria described.

4. In the complications and reoperation section, the author has mentioned that two subjects who had initial horizontal muscle surgery did not achieve desired outcome and underwent another horizontal muscle resection for correction. We presume that these two patients were from the partial abducens nerve palsy group and we just wish to know that these two patients were allotted to which group – surgical success group or surgical non-success group?

Disclosure

The authors report no conflicts of interest in this communication.