Long-term Surgical Outcomes of Augmented Bilateral Lateral Rectus Recession in Children With Intermittent Exotropia

The interesting article by Kim and associates compares the results of conventional vs augmented lateral rectus recession surgery in children with basic and divergence excess type of intermittent exotropia. The following observations/queries are in order.

Near-distance disparity is of special importance in children in the age group included in the present study. The authors make no mention of the postoperative deviation at near. Their data for overcorrection is for overcorrection at distance. It is important to know the postoperative deviation at near and if there was overcorrection at near, more so in children in whom the visual receptive field is usually limited to near and intermediate targets and who are at risk for amblyopia. Similarly, it appears that the authors have also measured stereopsis only for distance targets.

Also, the authors have included only those cases of divergence excess subtype in which the near-distance disparity is less than 20 prism diopters (PD). Now, by definition, divergence excess subtype includes cases with near-distance disparity more than 10 PD. That leaves us with a very narrow spectrum of patients with the divergence excess subtype (those similar to the basic subtype) to which the results of this study might apply. In essence, the results of the study may be more accurate for only the basic subtype, considering the fact that measurement accuracy to such a level may be very difficult in children in the said age group.

Pattern strabismus is another bone of contention. For example, if a patient has V-pattern exotropia with approximately 35 PD deviation in up gaze, 30 PD in primary gaze, and 20 PD in down gaze, performing augmented surgery for a deviation of 35 PD will almost surely lead to overcorrection in down gaze. As we would all agree, down gaze (reading position) is more important than up gaze. The authors make no mention of postoperative deviations in different gazes. What was the postoperative status of patients with pattern strabismus in the present study?

A similar argument may be made for cases with lateral incomitance, for which decreased surgical dosages are usually advised. What were the postoperative deviations in side gazes for subjects with lateral incomitance in the present study?

Finally, patients with hyperopia (preoperatively) have been undercorrected by 1–1.5 diopters. Is this advisable in children?

The authors’ comments/views on the above observations may help readers get better insight into the management of intermittent exotropia in children and learn more from the authors’ commendable experience of treating such a large number of subjects with a long follow-up period.

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Jan 6, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Long-term Surgical Outcomes of Augmented Bilateral Lateral Rectus Recession in Children With Intermittent Exotropia
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