To the Editor The rectus muscle plication is a useful strabismus surgical procedure as reported by Chaudhuri and Demer in the article titled “Surgical Outcomes Following Rectus Muscle Plication: A Potentially Reversible, Vessel-Sparing Alternative to Resection.”1 I first published the rectus plication procedure in 1991 and called it a modified rectus tuck.2 The modification involved suturing muscle to sclera, in contrast to a tuck that sutures muscle to muscle. The standard muscle-to-muscle tuck relaxes over time and was therefore generally abandoned. When I originally published the technique, like Chaudhuri and Demer, I classified it as a strengthening procedure. The plication is actually a rectus muscle tightening procedure. This distinction is important when planning strabismus surgery as tightening limits eye movement, whereas strengthening increases eye movement. A plication of the right medial rectus muscle causes slight limitation of abduction, thus inducing an eso shift in right gaze and having little effect in left gaze. A strengthening procedure would do the opposite and induce an eso shift in left gaze. Hence, an exotropia increasing in right gaze is best treated with a right medial rectus plication.