Reply to Correspondence

We thank Pooja Gupta and colleagues for their comments on our article, “Border Tissue Morphology Is Spatially Associated With Focal Lamina Cribrosa Defect and Deep-Layer Microvasculature Dropout in Open-Angle Glaucoma.”

Focal lamina cribrosa (LC) defect has been reported to be associated not only with glaucoma but also with myopia. The previous study by You and associates did not show focal LC defect in normal eyes. However, in other previous studies, the LC defect was found in myopic eyes without glaucoma. , If the axial length (AL) is longer, it seems that normal eyes also can have LC defects though their sizes or numbers are relatively smaller than those of eyes with glaucoma.

As you mentioned, open-angle glaucoma (OAG) eyes in our present study showed significantly longer AL than normal eyes. Considering that we speculated that microvasculature dropout (MvD) located near the border tissue and the border tissue length can be longer with axial elongation, longer AL could induce a higher presence of MvD in glaucoma eyes. However, the results we stressed using OAG eyes and normal eyes were firstly that MvD was found more frequently in more severe OAG eyes, and second, MvD was not found even in 1 normal eye as the previous study result. Even though we included the normal eyes matching AL with OAG eyes, there might be no different result.

The relationship between focal LC defect and MvD is important for understanding their implications in glaucoma pathogenesis. However, to compare the 2 factors, the specific parameters used in the study should be considered. For example, to compare the focal LC defect and MvD, several parameters such as presence, the size (or height), and the width of the focal LC defects and MvDs could be used for comparison. In the present study, we used cross-sectional images using Heidelberg enhanced depth imaging (EDI)–optical coherence tomography (OCT) to measure LC defect and en face images using swept-source OCT angiography to measure MvD. With OCT angiography, the width and height of MvD were measurable consistently; however, with EDI-OCT, it was especially difficult to measure the exact width of focal LC defect because of the overlying vessels or tissues above peripheral LC. Thus, we compared only measurable parameters such as presence and size of LC defect, and presence, width, and height of MvD. For direct comparison between focal LC defect and MvD, we only showed the locational correlation between the focal LC defect and MvD (Table 3 and Figure 2). To understand the clinical meaning of the parameters in glaucoma in detail, it is necessary to perform further research with an advanced device that can overcome these limitations.

See the original article for any disclosures of the authors.

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Mar 14, 2020 | Posted by in OPHTHALMOLOGY | Comments Off on Reply to Correspondence
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