Response to comment on: Optical coherence tomography angiography in acute unilateral nonarteritic anterior ischemic optic neuropathy: A comparison with the fellow eye and with eyes with papilledema.

Sir,

We thank Dr. Hayreh for his comments[1] on our study[2] and fully appreciate his volume of work and expertise on this subject.

Regarding some of the points raised – we agree that fundus fluorescein angiography (FFA) findings in non-arteritic anterior ischemic optic neuropathy (NAION) have been extensively reported and would like to explain that this study was not designed to compare optical coherence tomography angiography (OCT-A) with FFA or any other modality. It was aimed at trying to analyze the results of OCT-A in NAION, since it is a relatively new modality and a little is known about its utility in this disorder. Hence, we wish to clarify that we do not propose any new hypothesis regarding the pathophsiology of NAION based on this study, it would be very premature to do so since the technology and our understanding of OCT-A is still evolving. We do not claim to be the first to describe these findings and there are other studies which have tried to use OCT-A to delve deeper into the pathology of this disease[345] and we have cited them in the original article as well.

Visual fields are routinely tested using the Humphrey perimeter in everyday clinical practice and most studies on NAION[6] use this investigative modality. While we realize the inherent limitations of automated perimetry, we have described our visual field testing results based on the investigative modality available to us for routine use.

The terminology used to describe the vascular beds has been used in reference with the OCT-A and has been described in the methodology.

Again, we thank Dr. Hayreh for his interest in our article.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.