Relationship Between Visual Acuity, Colour Vision, Contrast Sensitivity and Stereopsis, and Road Traffic Accidents: A Systematic Review and Meta-Analysis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper presents a comprehensive analysis of the relationship between various visual functions and the occurrence of road traffic accidents (RTAs). The aim of this study is to evaluate the relationship between visual functions (visual acuity, color vision, contrast sensitivity, and stereopsis) and RTAs through a meta-analysis of observational studies. With several adjustments based on the suggestions provided, this paper has the potential to make a strong impact in the emerging field.

• The paper aims to evaluate the relationship between visual functions (visual acuity, color vision, contrast sensitivity, and stereopsis) and road traffic accidents (RTAs) through a meta-analysis of observational studies. For That, the authors are invited to be more specific in the title of the paper since it is very general with comparison to the study that is very specific and cover only visual acuity, color vision, contrast sensitivity, and stereopsis.
• The authors are invited to present the reason the study is conducted on healthy individuals (in the introduction section) so in this case the effect of visual diseases is not considered.
• The authors are invited to add the structure of the paper at the end of the introduction section for more clarity and paper organization.
• The authors used 35 studies from the literature and found that healthy individuals with visual acuity are not subject to RTA which is the normal thing, no new information is provided.
• The authors have found that stereopsis and contrast sensitivity have almost no effect on the increase of RTA. This conclusion is unfortunately based on a very small number of studies and should not be generalized. The authors are invited to address the limitation of small sample sizes, which may affect the reliability of findings.
• The authors are invited to explain the difference of their review findings and the results of Piyasena et al. in [9]. In the discussion section, the authors mentioned that their findings are the same found by Piyasena et al. in [9].
• The authors are invited to present the results and data in a graphical form for more clarity. Ensure forest plots are clearly labeled and include all relevant studies for each visual function.

Author Response

We, the authors, appreciate your comments as they have helped us to improve the quality of the manuscript. We have made several changes to the title, introduction, results and discussion, i.e. throughout the manuscript. 
We have tried to respond to your comments point by point, and you will find the responses in the attached file.
We hope that these changes meet your requirements and look forward to hearing from you if further changes are required.
Yours sincerely,

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The author has selected a compelling yet complex research topic. Given that vision is the primary source of information for drivers, visual impairments are inevitably linked to driving safety. However, the most challenging aspect lies in obtaining robust data to establish a causal relationship between visual impairments and road traffic accidents.

1. Introduction part: The data from the WHO offers a comprehensive global overview of traffic accident fatalities across various countries and regions, highlighting the critical importance of addressing road traffic safety issues. However, the research overview on the relationship between visual functions and road traffic safety is insufficiently detailed in the explanation section, making it challenging to clearly underscore the significance of studying visual functions in this context.
2. In the research conclusions, the authors highlighted issues related to study design and quality, emphasizing that the majority of participants were elderly. However, it is important to note that older adults are more likely to be selected as subjects precisely because they are more susceptible to declines in visual function. From a scientific research perspective, the framing of this as a limitation appears somewhat unreasonable.
3. Please request that the author provide further clarification on the relationship between national contexts, the development of road safety policies, and traffic accidents resulting from visual impairments.
4. The blue lines in Figures 2 to 6 are indeed a bit confusing.

Author Response

We, the authors, appreciate your comments as they have helped us to improve the quality of the manuscript. We have made several changes to the title, introduction, results and discussion, i.e. throughout the manuscript. 
We have tried to respond to your comments point by point, and you will find the responses in the attached file.
We hope that these changes meet your requirements and look forward to hearing from you if further changes are required.
Yours sincerely,

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The overall findings of this study are exhaustive and would likely be of interest to a number of readers. The introduction is well-developed, the methodology is generally well-described, and the results are clearly shown. It is particularly interesting that the authors highlighted if these came from low, middle, or high-income countries. There are some minor points to address in this manuscript. 

Line 13: Abstract - should add "of this study" after The aim...

Line 145: Unclear if this refers to if the VA results were averaged for both eyes, were averaged over time, or via another method. Please clarify.

Results: Overall table formatting should be improved, because it is difficult to read. Would suggest changing column structure or spacing to improve this.

Table 2: The number of participants from each study is unclear. I believe it is number of cases/controls, but this is not how it is shown in the heading. Also some acronyms do not seem to be explicitly stated in the text of caption (i.e. TNO)

Figures 2-4: Lines extending outside the box should be removed and notes should be larger

Discussion: The importance of the study/reason for conducting the study should be restated. Also, this section is relatively long and much of it is simply restating the results shown earlier. There are some interesting discussion points, but they seem to be a bit buried in the text. For instance, the points regarding stereopsis, VA, and reports from low, middle, and high-income countries could be highlighted more in the discussion.

Author Response

We, the authors, appreciate your comments as they have helped us to improve the quality of the manuscript. We have made several changes to the title, introduction, results and discussion, i.e. throughout the manuscript. 
We have tried to respond to your comments point by point, and you will find the responses in the attached file.
We hope that these changes meet your requirements and look forward to hearing from you if further changes are required.
Yours sincerely,

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

I like the paper very much - it focuses on a timely and safety-relavant topic, using the state-of-the-art methods of systematic review and meta-analysis. I have no major comment - I recommend the paper to be accepted for the journal publication.

Author Response

Dear reviewer,

Thanks for your feedback on our article.

Reviewer 5 Report

Comments and Suggestions for Authors

This paper reviewed the recent studies regarding the relationship among visual fucntions and road traffic accidents. The topic is interesting and deserves more effort. Here are some suggestions to enhance the contributions:

• Some of the literature are very old like over 40 years ago. The reviewer wonders if it suitable to be included for reference.
• The summary of current studies and research gap should be provided after these tables. 

Author Response

We, the authors, appreciate your comments as they have helped us to improve the quality of the manuscript. We have made several changes to the title, introduction, results and discussion, i.e. throughout the manuscript. 
We have tried to respond to your comments point by point, and you will find the responses in the attached file.
We hope that these changes meet your requirements and look forward to hearing from you if further changes are required.
Yours sincerely,

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I would like to thank the authors to answer my points

Comments on the Quality of English Language

Good English Quality

Reviewer 3 Report

Comments and Suggestions for Authors

The authors adequately responded to the minor comments. I would have preferred a more structured discussion, but it is acceptable.

Reviewer 5 Report

Comments and Suggestions for Authors

The paper is suitable for publication for its current version.