We read the article by Lee and associates with keen interest. We appreciate the authors for commendable work on epiblepharon repair in Down syndrome patients. The authors performed a combined Z-medial epicanthoplasty on patients with a prominent epicanthal fold by using modified Park’s Z- epicanthoplasty. However, the markings for the skin incision for Z-epicanthoplasty in Figure 4 appear to be those of the original Z-epicanthoplasty. In the original Z-epicanthoplasty, the middle of the epicanthal fold is marked as point A; point A is joined to point B, which is at the point of confluence of the epicanthal fold with the lower eyelid skin; point C is placed medial to point A; the distance between points A and C is the same as line AB; line AC is drawn as a horizontal bar, while in the modified Park’s Z- epicanthoplasty line AC is designed as an oblique line toward the mid glabella point. Unlike the original Z-epicanthoplasty, angle CAB becomes almost a straight line. The original technique had a tendency to develop a redundancy of the pretarsal skin near the medial canthus and a convergence of the pretarsal double fold toward the lacrimal lake in about 20% of cases, compared to <5% with the modified technique.
The authors mention that the recurrence rate of lower eyelid epiblepharon repair did not significantly differ between the 2 groups. However, there was a huge difference in the number of eyelids included in the 2 groups (only 22 eyelids of Down syndrome patients vs 1072 eyelids of non–Down syndrome patients). Similarly, there was a significant difference in the number of cases in the 2 groups requiring upper eyelid epiblepharon repair with or without Z-medial epicanthoplasty. In the Down syndrome patients, only upper eyelid epiblepharon repair was performed in 6 eyelids and combined with Z-medial epicanthoplasty in 34 eyelids. In non–Down syndrome patients only upper eyelid epiblepharon repair was performed in 192 eyelids and combined with Z-medial epicanthoplasty in 12 eyelids only. It would be inappropriate to compare the 2 grossly unequal groups as the recurrence rate may increase or decrease unless a statistically valid number of eyelids are operated.
The authors have speculated that the flatter nose in Down syndrome patients predisposes the cilia of the upper eyelids to rotate medially and eventually touch the cornea. There are several possible etiologic factors contributing to the pathogenesis of epiblepharon, which include failure of eyelid retractors to gain access to skin, failure of interdigitation of septae in the subcutaneous plane, and weak attachment of the pretarsal orbicularis oculi muscle and skin to the tarsus below, thus raising a skin fold near the eyelid margin and pushing the eyelashes toward the cornea. However, in view of the hypotonia or low muscle tone that generally affects all muscles in the body of Down syndrome patients, we would like to add that hypotonia of eyelid muscles may be yet another factor in the pathogenesis of epiblepharon and the higher recurrence rate in this subset of patients.