We appreciate the comments by Tan and Seah regarding our article on HRQOL in patients with BEB.1 They suggest that we have failed to consider a potential study design limitation that may partly explain our observed results, that is, referral bias. They suggest that our comparison group of patients with HFS has less severe disease, thus had we included a more representative population of patients with HFS, the observed differences would have been minimized. It is important to remember that the National Eye Institute Visual Function Questionnaire measures vision-related quality of life. Thus, the fact that patients with HFS with more severe disease characterized by non-vision-related manifestations may not have been included in our study is of little consequence, as the objective was to characterize vision-related HRQOL. More importantly, the reality is that the Department of Ophthalmology, University of Alabama at Birmingham, treats a wide range of patients with HFS; therefore, the potential for referral bias is quite low. Finally, according to Table 2 in our article, the average disease duration was similar for both groups, as were several other disease-related characteristics, providing indirect evidence that the groups may be similar with respect to disease severity.
McGwin G, Vaphiades MS, Kline LB. Health-Related Quality of Life in Blepharospasm and Hemifacial Spasm—Reply. Arch Ophthalmol. 2007;125(8):1141. doi:10.1001/archopht.125.8.1141-b