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Centration of Clear Zone Over the Pupil Is the Best Strategy for Rotational Autografts—Reply

Centration of Clear Zone Over the Pupil Is the Best Strategy for Rotational Autografts—Reply In reply We thank Dr Harris for his letter to the editor concerning our simplified mathematical model for corneal rotational autograft. We agree with Dr Harris that there are limitations to our simplified model, especially in clinical situations that differ from our stated assumptions. We also agree that moving the scar beyond the pupillary margin and relocating the center of the largest zone of clear cornea over the center of the entrance pupil is the goal of the surgery. To simplify our calculations, we limited our analysis to situations where the center of the pupil and the center of the cornea were in close proximity. In our patient, suturing the intraocular lens would have resulted in a relatively unpredictable shift in the pupil center relative to the corneal center. Another assumption that we made in our simplified model is the circular shape of the cornea. We are currently attempting to generate a more involved mathematical solution assuming a horizontally oval corneal shape and a distance separating the center of the cornea from the center of the pupil. We suspect that in these situations, the displacement may have to be in a direction other than the superior direction; temporal displacement may be more advantageous in some cases (such as the one presented by Dr Harris and as described in the classic article by Bourne and Brubaker). In our case report, the preoperative visual acuity did not improve with refraction. Of note, the patient had preoperative diplopia and triplopia. Postoperatively with secondary intraocular lens implantation and a clear visual axis, he could be refracted. We thank Dr Harris for his interest in our article and for his comments. We also thank Dr Jonas for his insightful comments and for his confirmation of our findings that for the average cornea (having an 11-mm diameter), the optimal corneal rotational autograft diameter would be 8 mm. We agree that the autograft diameter would have to be modified for corneal diameters outside the normal range. We look forward to incorporating his calculations in such cases, particularly those involving young children, and thank him for his interest in our work. Correspondence: Dr Afshari, Department of Ophthalmology, Duke University Medical Center, Box 3802, Durham, NC 27710 (afsha003@mc.duke.edu). Financial Disclosure: None reported. Funding/Support: This work was supported by Research to Prevent Blindness (Dr Afshari). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Ophthalmology American Medical Association

Centration of Clear Zone Over the Pupil Is the Best Strategy for Rotational Autografts—Reply

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Publisher
American Medical Association
Copyright
Copyright © 2007 American Medical Association. All Rights Reserved.
ISSN
0003-9950
eISSN
1538-3687
DOI
10.1001/archopht.125.7.993
Publisher site
See Article on Publisher Site

Abstract

In reply We thank Dr Harris for his letter to the editor concerning our simplified mathematical model for corneal rotational autograft. We agree with Dr Harris that there are limitations to our simplified model, especially in clinical situations that differ from our stated assumptions. We also agree that moving the scar beyond the pupillary margin and relocating the center of the largest zone of clear cornea over the center of the entrance pupil is the goal of the surgery. To simplify our calculations, we limited our analysis to situations where the center of the pupil and the center of the cornea were in close proximity. In our patient, suturing the intraocular lens would have resulted in a relatively unpredictable shift in the pupil center relative to the corneal center. Another assumption that we made in our simplified model is the circular shape of the cornea. We are currently attempting to generate a more involved mathematical solution assuming a horizontally oval corneal shape and a distance separating the center of the cornea from the center of the pupil. We suspect that in these situations, the displacement may have to be in a direction other than the superior direction; temporal displacement may be more advantageous in some cases (such as the one presented by Dr Harris and as described in the classic article by Bourne and Brubaker). In our case report, the preoperative visual acuity did not improve with refraction. Of note, the patient had preoperative diplopia and triplopia. Postoperatively with secondary intraocular lens implantation and a clear visual axis, he could be refracted. We thank Dr Harris for his interest in our article and for his comments. We also thank Dr Jonas for his insightful comments and for his confirmation of our findings that for the average cornea (having an 11-mm diameter), the optimal corneal rotational autograft diameter would be 8 mm. We agree that the autograft diameter would have to be modified for corneal diameters outside the normal range. We look forward to incorporating his calculations in such cases, particularly those involving young children, and thank him for his interest in our work. Correspondence: Dr Afshari, Department of Ophthalmology, Duke University Medical Center, Box 3802, Durham, NC 27710 (afsha003@mc.duke.edu). Financial Disclosure: None reported. Funding/Support: This work was supported by Research to Prevent Blindness (Dr Afshari).

Journal

Archives of Ophthalmology – American Medical Association

Published: Jul 1, 2007

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