In regard to the article, "Surgery on the Normal Eye in Duane Retraction Syndrome," by Dr Saunders et al (J Pediatr Ophthalmol Strabismus. 1994;31:162-169), for your readership interested in the surgical management of this clinical entity, I would like to add to the authors' bibliography our series of four patients, each receiving a posterior fixation suture to the medial rectus of the fellow eye, in their care.1 We concur that the surgical goals of alignment in primary position, elimination of a significant face turn, and improved comitance in lateral gaze, are all benefits to be gained with the described approach. However, given the data by Matteuci2 and Miller et al,3 histologically demonstrating an absence of the sixth cranial nerve in Duane Syndrome, I cannot agree with their contention (on page 166) that Herings law explains the improved abduction through an "increased innervational output to the affected eye" without electromyograph (EMG) evidence of increased firing in the region of the lateral rectus or accessory abductors. Clinically, one would have to perform the medial rectus recession of the Duane eye, and at a second sitting, operate on the fellow eye with a posterior fixation suture, to evaluate any increase in abduction due to the second procedure alone.
Case 1 in our series was such a patient, and although comitance was improved into the field of the underacting lateral rectus, a strong case for having improved abduction, as well, is not proposed. The posterior fixation suture certainly balances underactions well, but if we are to believe the pathoanatomical studies, any suggestion of improved abduction should be considered to have occurred on the basis of having released the tight medial rectus, so common in this syndrome.
FIGURE: (A) 41-year-old woman with mild Duane retraction syndrome in the left eye associated with moderate limitation of abduction. (B) Same patient 6 months after 6-millimeter right medial rectus muscle recession. Abduction has improved in the unoperated Duane eye.
1. Lingua RW, Walonker F. Use of the posterior fixation suture in type 1 Duane's syndrome. Journal of Ocular Therapeutics and Surgery. 1985;4:107-111.
2. Matteuri P. I difetti consenti di abduzione con particolare risuardo alia patogenesi. Rassegna Italiana dOttalmologia. 1946;15:345-380.
3. Miller NR, Kiel SM, Green WR, et al. Unilateral Duane's retraction syndrome (type 1). Arch Ophthalmol. 1982;100: 1468- 1472.
ROBERT W. LINGUA, MD
We thank Dr Lingua for his comments and wish to apologize for not including his excellent article in our bibliography.1 It appeared in the Journal of Ocular Therapeutics and Surgery, which is no longer published and was not retrieved in our Mediine search. His photographs clearly demonstrate the improved comitance that can be obtained by using posterior fixation sutures in the normal eye in selected cases of Duane retraction syndrome. In this article, Dr Lingua also states (page 111) that "Bering's law cannot explain improved comitance in Duane's syndrome when a counterparesis procedure is performed on the yolk medial of the underacting lateral rectus, unless increased firing of the accessory abductors is demonstrated on EMG studies." This assertion would be true in patients devoid of abduction in the Duane eye. However, these are the same patients in whom posterior fixation of the contralateral medial rectus muscle is ineffective. Patients with mild-tomoderate limitation of abduction must have partially intact 6th cranial nerve function to explain ocular movement significantly past the midline. Bering's law therefore would apply and potentially be useful in improving ocular motility.
While we have not performed EMG studies to support our contention, we have treated patients with type I Duane retraction syndrome who experienced improved abduction in the Duane eye when surgery was limited to the medial rectus muscle in the normal eye. Because the Duane eye was untreated, we believe that the improved abduction ability can only be explained by invoking Bering's law.
A 41-year-old woman presented with a long-standing left face turn associated with a mild type I Duane syndrome in the left eye. Motility evaluation revealed an esotropia of 20 prism diopters in primary gaze position at distance and 10 Δ at near. There was mild retraction of the left eye on adduction and -2 limitation of abduction. The patient was treated with a 6-millimeter recession of the right medial rectus muscle. Six months postoperatively, an esophoria of 5 ? was present at distance and she was orthophoric at near. Rotations revealed -1 limitation of adduction in the right eye and -1 limitation of abduction in the left eye. There was no demonstrable face turn. Diplopia visual fields revealed single vision except beyond 30° up gaze and left gaze.
1. Lingua RW, Walonker F. Use of the posterior fixation suture in type 1 Duane's syndrome. Journal of Ocular Therapeutics and. Surgery. 1985:4:107-111.
RICHARD A. SAUNDERS, MD
M. EDWARD WILSON, MD
ETTALEAH C. BLUESTEIN, MD
ROBBIN B. SINATRA, MD