Reply: Distinct Features in Koreans with Involutional Blepharoptosis.

Abstract

Sir: We thank Dr. Hwang for his interest in our recent article entitled “Distinct Features in Koreans with Involutional Blepharoptosis.”1 We appreciate his criticisms of our work. Dr. Hwang rebutted our results on Korean patients with involutional blepharoptosis who showed slightly decreased levator muscle function. His rebuttal was based on a study that described normal levator function in Koreans (we found that the study he cited was published in Plastic and Reconstructive Surgery in 2008, not in Archives of Aesthetic Plastic Surgery in 2002).2 In the cited study, subjects showed larger levator function than what we reported: 11.9 ± 1.6 mm (11.9 ± 1.6 mm in male patients and 11.9 ± 1.6 mm in female patients) in the cited study and 10.7 ± 2.2 mm (10.5 ± 2.4 mm in male patients and 10.8 ± 2.2 mm in female patients) in our study. However, the subjects enrolled in the cited study were ordinary people, aged between 6 and 80 years, not aging patients with involutional blepharoptosis. Meanwhile, our study included patients with involutional blepharoptosis only, aged 63.1 ± 10.0 years. Furthermore, among the elderly people included in the cited study, levator function was decreased, similar to our results: 10.9 ± 1.2 mm in male patients and 12.0 ± 0.9 mm in female patients aged 50 to 59 years, and 7.8 ± 2.0 mm in male patients and 10.4 ± 1.6 mm in female patients aged older than 60 years.2 To address the issue of fatty infiltration on the levator muscle, Dr. Hwang wrote that he could not find the content that “fatty levator muscle was found in 25.6% of eyes with involutional ptosis” in the article by Tucker and Verhulst.3 However, Tucker and Verhulst clearly state that 42 of the 164 levator muscles (25.6 percent) demonstrated some degree of fatty infiltration in their study of 164 eyelids that underwent aponeurotic ptosis repair. They observed that eyelids with fatty levator muscles had a reduced levator function and a higher rate of surgical revision compared with normal appearing levator muscles.3 Unfortunately, regarding the study by Jeong et al.,4 our statement was misleading, as mentioned by Dr. Hwang. We intended to present that fat deposits on the anterior surface of the tarsal plate, especially the medial side, were also found in this study (data not shown in the article) and that fatty infiltration of levator muscles may be related to increased fat deposits on surrounding structures, including subcutaneous, suborbicularis, preseptal, and pretarsal tissue, in the Asian upper eyelid. We proposed that lipotoxicity could be a mechanism by which fat changes in the levator muscle weaken muscle power. Although a causal relationship for lipotoxicity of cardiac lipids on cardiac function could not be derived from the literature, as Dr. Hwang pointed out, the article we cited demonstrated that exercise training decreases cardiac lipid content and improves cardiac function.5 Another study showed that an increased cardiac lipid content in rodents leads to contractile dysfunction.6 In addition, fat gain was reported as a potential cause of sarcopenia, as we cited in our article.7 This is just a hypothesis, of course, and further studies are warranted to investigate the mechanism. DISCLOSURE The authors have no financial to declare in relation to the content of this communication. Chang Yeom Kim, M.D., Ph.D. Sang Yeul Lee, M.D., Ph.D. Department of Ophthalmology Yonsei University College of Medicine Seoul, Republic of Korea