Author Response: Comparison of Risk Factor Profiles for Primary Open-Angle Glaucoma Subtypes Defined by Pattern of Visual Field Loss: True Risk Factors or Arbituary Definition?
Author Response: Comparison of Risk Factor Profiles for Primary Open-Angle Glaucoma Subtypes Defined by Pattern of Visual Field Loss: True Risk Factors or Arbituary Definition?
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作者回应：根据视野丧失模式定义的原发性开角型青光眼亚型的风险因素概况比较：真正的风险因素还是任意定义？
DOI：
10.1167/iovs.15-17944
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发表时间：
2015
影响因子：
4.4
通讯作者：
Pasquale,LouisR
中科院分区：
文献类型：
--
作者：
Kang,JaeH;Loomis,StephanieJ;Rosner,BernardA;Wiggs,JaneyL;Pasquale,LouisR
We thank Ratnarajan et al. 1 for their interest in our work2 and for the opportunity to clarify aspects of the study. First Ratnarajan et al. 1 were concerned that our definitions for the primary open-angle glaucoma (POAG) with paracentral and peripheral visual field (VF) defect groups were arbitrary and that we did not follow predefined international glaucoma guidelines. Importantly, Ratnarajan et al. 1 were concerned that because the paracentral VF defect group included those with paracentral and peripheral VF defects that our results mainly reflected differences in association with later versus earlier diagnosis rather than with different VF loss patterns. To the best of our knowledge, we are not aware of any clear predefined internationally accepted guidelines for distinguishing POAG subtypes by VF patterns. Absent such guidelines, we allowed those with both types of VF defects for the paracentral group because this definition balanced the need for accuracy with statistical power. Our cases were incident POAG cases, with generally mild early VF loss, and in this setting, among those with any paracentral loss, those with isolated paracentral loss only was relatively uncommon (21%), whereas most with clear paracentral loss also had some peripheral VF defects; thus, we included those with isolated as well as early paracentral and peripheral defects to maximize power. However, our definition is supported by several key clinical observations. For example, compared to cases of peripheral VF loss only, our paracentral VF loss group showed lower mean intraocular pressure (IOP), higher cup-to-disk ratio at diagnosis, and significantly (P ¼ 0.0002) more defects in the superior than in the inferior hemifield, which is entirely consistent with reports from studies that have included only those with isolated paracentral VF loss. 3, 4 Also, in a recently published computerized machine learning approach to objectively categorize VFs, 13,213 Humphrey VFs were classified into 17 archetypes of VF loss patterns. Interestingly, in the paper by Elze et al., 5 VF archetype number 14 was most representative of an archetype of paracentral VF loss and indeed included paracentral, Bjerrum region, and nasal step involvement, closely resembling our definition.A second concern was that VF mean deviation (MD) parameters were not provided in the two groups. When we evaluated a random sample of the paracentral VF loss cases (n¼ 31) and peripheral VF loss cases (n ¼ 54), we observed that the MD was-4.5 (SD ¼ 3.2) dB in the paracentral VF loss group and-2.7 (SD ¼ 2.4) dB in the peripheral VF loss group, with 74% and 91% considered having mild disease severity (ie, MD better than-6 dB based on the Hodapp-Anderson-Parrish grading scheme6) in the paracentral and peripheral VF groups, respectively; this refutes the claim that our paracentral VF loss group consisted mainly of those with advanced loss. In contrast, in a random sample (n ¼ 18) of cases that we censored in analyses due to advanced loss with both paracentral and peripheral defects, the MD was-10.6, indicative of moderate disease severity, based on the Hodapp-Anderson-Parrish grading scheme. 6 A third concern was our reliance on self-reporting for glaucoma case confirmation. We agree that this was a limitation, which was mentioned in the Discussion. However, it should be emphasized that although the first step in the case
