The Effect of Ocular Perfusion Pressure on Retinal Thickness in Young People with Presumed Systemic Hypotension

Round 1

Reviewer 1 Report

Nice manuscript, well presented work by the authors.

2.1 Sampling: "estimated prevalence for BP" - i am not quite sure what you mean, and the article cited describes a study on an irish population?

otherwise quite fine

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The ocular perfusion pressure (OPP) has been investigated pretty good. Glaucoma and ganglion cells are the characters mainly involved in modifications or alterations of OPP, with more or less severe consequences on eye health and visual function.

Though Introduction is a little bit long and the sample of 15 patients is probably too small, the manuscript is well-organized and well-written. Reference list is rather updated. 30 eyes were investigated, but I do not think there is much distinction between two eyes of the same patients about OPP.

Please, shorten Introduction and Discussion making them more fluent and less redundant. I suggest to keep it simple trying to simplify and convey the message of the study to the readers without digressions.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The paper is very interesting and well written. I congrat with the authors and I think it could be of some interest and landmark for future investigations as already highlighted by the same authors.

However, I have main concerns especially related to the introduction and methods and to my point of view they need to be improved. Indeed, the introduction does not provide a complete overview about the glaucoma disease to the readers that are not glaucoma glaucoma specialists.

Below I will be very grateful if authors could address shortly my suggestions:

Introduction

1) The introduction needs to be rewritten. It is too long, verbose and confusing. Please also start saying what it is glaucoma…later discuss briefly main risk factors and the role of MOPP, DOPP ans SOPP. At the end underline why the paper is original and its aims. Please also summary the most significative literature and move the rest (for example the gender-related differences) in the discussion.  

2) Please define better the glaucoma as a “heterogeneous group” of chronic neurodegenerative disorders characterized by a relatively selective, progressive damage to the retinal ganglion cells (RGCs) and their axons, which leads to axon loss and visual field alterations.

Please use the following reference:

• doi: 10.3390/ijms22094323.

3) What is “PSH”? there is not an explanation of acronimus before in the introduction.

4) Please add some epidemiological data regarding the impact of glaucoma to highlight how the knowledge of blood flow pathophysiology is a crucial. It is the most common cause of irreversible blindness worldwide, currently affecting almost 80 million people, or more than 1% of the global population. By 2010, 1 out of 15 blind people was blind due to glaucoma, and 1 of 45 visually impaired people was visually impaired due to glaucoma, highlighting the increasing global burden of glaucoma. In this way, the reader will understand why the topic that authors are discussing is an “hot topic” and of interest for the pubblic health.

Please use the following references:

• doi: 10.1016/j.ophtha.2014.05.013
• doi: 10.1177/1120672120960339.

 

5) Please explain briefly that the mechanism of neurodegeneration in glaucoma is not sufficiently elucidated, and in particular, the mechanisms of this so-called extraretinal neurodegeneration are poorly understood. This will justify the background of the study. Indeed, as stated by the authors, a deeper knowledge regarding the key factors associated with progression, could potentially be used of great importance.

Please use the following reference:

• doi: 10.3390/ijms22031039

 

6) Treatments aimed at decreasing IOP are ineffective in many cases. Indeed IOP is not a static parameter but undergoes dynamic changes. Please clarify this aspect in the Introduction, using the following reference:

• doi: 10.1155/2019/9890831. PMID: 30809389; PMCID: PMC6369465.

 

7) The management of glaucoma patients may benefit from surgery to preserve visual function. Surgical intervention, considered the most effective procedure for lowering IOP in uncontrolled glaucoma with OH, is not available to the vast majority of patients in need or multiple interventations could be required to reach an acceptable IOP target; similarly, surgery is unavailable to more than three-quarters of patients suffering from vision impairment due to cataract or uncorrected refractive error, conditions that are fully treatable surgically. In this scenario, the perspective a deeper knowledge of risk factors in selected cases could completely change the history of those patients, providing personalized therapeutic approach.

Additionally, refractory glaucoma cases are characterized by advanced optic nerve damage, severe impairment of visual field, and a non-controlled intraocular pressure (IOP) despite maximal medical therapy and previous glaucoma surgeries. Please point these aspects in the Introduction. Indeed, this could provide a better explaination and clarify why assessing the thickness of the GCC and ONH-RNFL thickness may be of value in people with systemic hypotension as they may suffer reduced perfusion translating into optic neuropathy over time.

Please use the following references:

• doi:10.3389/fphar.2020.573238
• doi: 10.3390/jcm9072039.

 

Methods

1) Ethical approval? Please mention in the methods and in the dedicated section of the template. Also the enrollement period of the study.

2) “…as no previous studies on systemic hypotension and the retina is known to have been 116 done. The estimated prevalence of BP is 0.3 based on a study by Owens et al. 22 for an 117 African population.” Please move this part in the discussion or use it to expain in the introduction your paper is original. The methids section should describe only the methods and no explanation of them should be provided.

3) “To satisfy the selection criteria, screening was carried out on all participants.” It is obvious. Please delete and list more in details the inclusion and exclusion criteria. No comments should be used in this section

4) Regarding the “Retinal Thickness measurements” using the Optovue iVue 100 OCT, please specify the the softaware of the device.

 

I hope the authors will consider my suggestions useful to improve their already interestingg paper.

Looking to review the manuscript once again

Best regards,

 

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Authors have provided a detailed replay to all my previous queries. The quality of presentation and the description of methods has been improved. I have no additional commets or suggestions for the authors.