The Effect of Horizontal Rectus Muscle Surgery on Distance-Near Incomitance
Paul H. Phillips, MD; Katherine J. Fray, CO; Hanya Qureshi; Brita S. Rook, MD; Lamonda Corder, BSN; Robert S. Lowery, MD; Adrian P. Grigorian, MD
University of Arkansas for Medical Sciences
Little Rock, Arkansas
Introduction: To determine the effect of horizontal rectus muscle surgery on distance-near incomitance.
Methods: Prospective evaluation of patients > 7 years old who had medial rectus or lateral rectus muscle surgery between 12/09 and 7/12. PACT testing was performed at distance (6 meters) and near (0.3 meters) after > 1 hour of monocular occlusion at the pre-operative and post-operative examinations. The change in distance-near incomitance was calculated. Post-operative examinations within 1 week and closest to 1 year after surgery were analyzed. Patients with muscle fibrosis or paralysis were excluded.
Results: Forty-five patients met inclusion criteria. Twenty-three patients had esotropia treated with medial rectus muscle recessions (21 patients) or lateral rectus muscle resections (2 patients). Twenty-two patients had exotropia treated with lateral rectus muscle recessions (18 patients) or medial rectus muscle resections (4 patients). Post-operative examinations within one week after surgery were obtained in 44 patients. The change in distance-near incomitance was </= 5 prism diopters (pd) in 37 patients; </= 10 prism diopters in 42 patients. Follow-up examinations 6 – 24 months after surgery were obtained in 28 patients. The change in distance-near incomitance was </= 5 pd in 20 patients; </= 10 pd in all 28 patients. Change in distance-near incomitance did not correlate with the specific surgical procedure (TOST p-value < 0.05 for 90% CI +/- 2 pd).
Discussion: Horizontal rectus muscle surgery does not have a clinically significant effect on distance-near incomitance.
Conclusion: It is not necessary to consider distance-near incomitance when choosing between medial rectus and lateral rectus muscle surgery.
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