Journal of Pediatric Ophthalmology and Strabismus

Letters to the Editor 

SURGICAL DOSES FOR THE ENHANCED GROUP

Michael X Repka, MD; Constance E West, MD

Abstract

The methods in our recently published article, "A Comparison of Surgical Techniques for the Treatment of Acquired Esotropia with Increased Accommodative Convergence/Accommodation Ratio" (J Pediatr Ophthalmol Strabismus 1994:31:232-237), inadvertently oversimplify the determination of the enhanced surgical dosages. There will be difficulty determining the amount of surgery actually performed in the enhanced or "near angle* surgery group from the published data. To alleviate this problem we wish to provide the readers with the actual surgical dosages.

The surgical dosages for the "enhanced" surgery group were based on the near angle. However, there was some variability in the actual surgery performed. Because this study was retrospective we found that the surgeon would modify the surgical dosage based on his or her consideration of the refractive error and the magnitude of the distance-near disparity. The surgeon often increased the surgery beyond that determined by the near angle with correction. This decision was made especially for patients with low amounts of hypermétropie and fusion. Such patients were thought to have an excellent possibility of satisfactory alignment without wearing refractive correction. Thus, the amount of surgery was based upon the near angle, but there were some patients who received surgical dosages beyond that calculated for the near angle measured with hypermétropie correction. To clarify this variability in near-angle surgical dosing, we are adding a column to Table 2 of our original paper. These added data document the actual amount of surgery performed in each patient (Table). Consider patient 31 as an example. This patient had 2.00 D of hypennetropia, a 5-prism-diopter esotropia while wearing full hypermétropie distance correction, and a 10-prism-diopter esotropia at near through a bifocal. There was a 50-prism-diopter deviation at near without correction. The amount of surgery chosen was based upon the near angle without correction. The patient underwent 6-millimeter bilateral medial rectus muscle recession. This patient thus had more surgery than her near deviation with correction would have allowed.

Table

The assumptions made in calculating the millimeters of enhancement for small deviations were not in the original article. These are incorporated in the Table legend.

This study was retrospective and these children were treated while the surgical management of distance-near disparity esotropia was evolving. We acknowledge that the amount of surgery performed for the near angle group was inconsistent. However, each patient received surgery for at least near angle and some patients actually received more. Therefore, we believe that our results support the original conclusion that surgery based on the near angle is safe and provides the opportunity for good motor and sensory alignment. The advantage of enhanced surgery found in this study was the reduced need for continued spectacle and bifocal usage. The disadvantage was an increased risk of overcorrection when compared with distance angle determined surgical dosages. The data are inadequate to comment on the value of surgery enhanced beyond the near angle.

TABLE

Enhanced Surgery…

The methods in our recently published article, "A Comparison of Surgical Techniques for the Treatment of Acquired Esotropia with Increased Accommodative Convergence/Accommodation Ratio" (J Pediatr Ophthalmol Strabismus 1994:31:232-237), inadvertently oversimplify the determination of the enhanced surgical dosages. There will be difficulty determining the amount of surgery actually performed in the enhanced or "near angle* surgery group from the published data. To alleviate this problem we wish to provide the readers with the actual surgical dosages.

The surgical dosages for the "enhanced" surgery group were based on the near angle. However, there was some variability in the actual surgery performed. Because this study was retrospective we found that the surgeon would modify the surgical dosage based on his or her consideration of the refractive error and the magnitude of the distance-near disparity. The surgeon often increased the surgery beyond that determined by the near angle with correction. This decision was made especially for patients with low amounts of hypermétropie and fusion. Such patients were thought to have an excellent possibility of satisfactory alignment without wearing refractive correction. Thus, the amount of surgery was based upon the near angle, but there were some patients who received surgical dosages beyond that calculated for the near angle measured with hypermétropie correction. To clarify this variability in near-angle surgical dosing, we are adding a column to Table 2 of our original paper. These added data document the actual amount of surgery performed in each patient (Table). Consider patient 31 as an example. This patient had 2.00 D of hypennetropia, a 5-prism-diopter esotropia while wearing full hypermétropie distance correction, and a 10-prism-diopter esotropia at near through a bifocal. There was a 50-prism-diopter deviation at near without correction. The amount of surgery chosen was based upon the near angle without correction. The patient underwent 6-millimeter bilateral medial rectus muscle recession. This patient thus had more surgery than her near deviation with correction would have allowed.

Table

TABLEEnhanced Surgery

TABLE

Enhanced Surgery

The assumptions made in calculating the millimeters of enhancement for small deviations were not in the original article. These are incorporated in the Table legend.

This study was retrospective and these children were treated while the surgical management of distance-near disparity esotropia was evolving. We acknowledge that the amount of surgery performed for the near angle group was inconsistent. However, each patient received surgery for at least near angle and some patients actually received more. Therefore, we believe that our results support the original conclusion that surgery based on the near angle is safe and provides the opportunity for good motor and sensory alignment. The advantage of enhanced surgery found in this study was the reduced need for continued spectacle and bifocal usage. The disadvantage was an increased risk of overcorrection when compared with distance angle determined surgical dosages. The data are inadequate to comment on the value of surgery enhanced beyond the near angle.

TABLE

Enhanced Surgery

10.3928/0191-3913-19950101-17

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