Strabismus Surgical Numbers
 
     
 
 
  The following table can be used as a guideline in planning strabismus surgery. These numbers have been derived from Parks, with modifications from the surgical experience of the author. The numbers are only a guide and should be modified as necessary.  
  Binocular Surgery  
 
Esotropia Exotropia
MR OU Recession
15 ∆ - 3.0 mm
20 ∆ - 3.5 mm
25 ∆ - 4.0 mm
30 ∆ - 4.5 mm
35 ∆ - 5.0 mm
40 ∆ - 5.5 mm
50 ∆ - 6.0 mm
60 ∆ - 6.5 mm
70 ∆ - 7.0 mm
LR OU Resection*
15 ∆ - 3.5 mm
20 ∆ - 4.5 mm
25 ∆ - 5.5 mm
30 ∆ - 6.0 mm
35 ∆ - 6.5 mm
40 ∆ - 7.0 mm
50 ∆ - 8.0 mm
LR OU Recession
15 ∆ - 4.0 mm
20 ∆ - 5.0 mm
25 ∆ - 6.0 mm
30 ∆ - 7.0 mm
35 ∆ - 7.5 mm
40 ∆ - 8.0 mm
50 ∆ - 9.0 mm
MR OU Resection
15 ∆ - 3.0 mm
20 ∆ - 4.0 mm
25 ∆ - 5.0 mm
30 ∆ - 5.5 mm
35 ∆ - 6.0 mm
40 ∆ - 6.5 mm
* When a lateral rectus resection is done for residual esotropia after a large medial rectus recession (6.0 mm or larger), these numbers should be lowered.
 
  Monocular Surgery  
 
Esotropia Exotropia
MR Recession
15 ∆ - 3.0 mm
20 ∆ - 3.5 mm
25 ∆ - 4.0 mm
30 ∆ - 4.5 mm
35 ∆ - 5.0 mm
40 ∆ - 5.5 mm
50 ∆ - 6.0 mm
60 ∆ - 6.5 mm
70 ∆ - 7.0 mm
LR Resection
3.5 mm
4.0 mm
5.0 mm
5.5 mm
6.0 mm
6.5 mm
7.0 mm
7.5 mm
8.0 mm
LR Recession
15 ∆ - 4.0 mm
20 ∆ - 5.0 mm
25 ∆ - 6.0 mm
30 ∆ - 6.5 mm
35 ∆ - 7.0 mm
40 ∆ - 7.5 mm
50 ∆ - 8.5 mm
MR Resection
3.0 mm
4.0 mm
4.5 mm
5.0 mm
5.5 mm
6.0 mm
6.5 mm
 
  Three Muscle Surgery  
 
For large amounts of correction, surgery on three muscles may be planned for the primary operation. This amount of surgery can be judged from the above tables. This works especially well in adults, where one muscle can be placed on an adjustable suture. The adjustable suture should be done on the eye for which two muscles are being operated.
 
  Vertical Numbers  
 
A rule of thumb for vertical surgery is 3 prism diopters of vertical correction for every millimeter of recession. Inferior rectus recessions are notorious for late overcorrections therefore, under most circumstances, do not recess the inferior rectus muscle more than 5 mm to 6 mm. Superior rectus recessions for dissociated vertical deviation (DVD), on the other hand, must be large, with the minimum recession of approximately 5 mm and a maximum of 9 mm (fixed suture technique).
 
  Kestenbaum Procedure for Nystagmus  
 
Face turn to the RIGHT
To correct the right face turn (eyes shifted to a left null point), move the eyes to primary position by moving both eyes to the right.
 
 
LEFT EYE
RIGHT EYE
Degree of Face Turn
Recess LR
Resect MR
Recess MR
Resect LR
Classic
< 20°
7 mm
6 mm
5 mm
8 mm
Parks
30°
9 mm
8 mm
6.5 mm
10 mm
Classic +40%
45°
10 mm
8.5 mm
7 mm
11 mm
Classic +60%
50°
11mm
9.5 mm
8 mm
12.5 m