Correlation between Eye Movements and Asthenopia: A Prospective Observational Study

Round 1

Reviewer 1 Report

The topic is interesting, and the study was conducted nicely. I have only minor suggestions.

1. Although the CVS-Q was average scored, I guess that individual item correlations with the eye-tracking parameters could be informative.

2. I would like to see more information regarding the oculomotor status of the patients that generate symptoms as a fusional amplitude, near point of convergence.

3. The lack of significative correlation of the eye-tracking parameters could be related to the huge variability of the data. Instead of median and IQ range it would be more interesting to show individual data spread in figure 1.

4. In the discussion section, include information regarding the high variability of the Eye-Tracking measurements.

Author Response

Point 1: Although the CVS-Q was average scored, I guess that individual item correlations with the eye-tracking parameters could be informative. 

Response 1: Thanks for the reviewer’s comments. We analyzed about the correlations between individual item from CVS-Q with the eye-tracking parameters. Some positive results were reached. However, the results would be too long and confused if we added this part to the manuscript. So we decided to enroll more participants and specifically to write about this topic in another research.

Point 2: I would like to see more information regarding the oculomotor status of the patients that generate symptoms as a fusional amplitude, near point of convergence.

Response 2: Thanks for the reviewer’s advice. We checked the eye position for all participants but we did not record the oculomotor status. The reason was that we thought examinations like fusional amplitude or near point of convergence would put stimulus on students’ accommodation and might influence the accuracy of the examinations. In further research we would extend the test period and record the oculomotor status on another day.

Point 3:The lack of significative correlation of the eye-tracking parameters could be related to the huge variability of the data. Instead of median and IQ range it would be more interesting to show individual data spread in figure 1.

Response 3: Thanks for the reviewer’s comments. The eye-tracking parameters did show great variability in our research and the deviation bar in Fig 1 had revealed this. Individual data spread in a scatter diagram would provide more information but the chart would also be more complicated and the result cannot be expressed clearly. So we decided to publish the raw data as a choice for readers who are interested in this topic.  

Point 4: In the discussion section, include information regarding the high variability of the Eye-Tracking measurements.

Response 4: Thanks for the reviewer’s comments. Eye-Tracking measurements have great variability [1-2]. Our data were also in agreement with previous research. We added some discussion regarding this area in the revised manuscript.

[1]Tao L, Wang Q, Liu D, Wang J, Zhu Z, Feng L. Eye tracking metrics to screen and assess cognitive impairment in patients with neurological disorders. Neurol Sci. 2020 Jul;41(7):1697-1704.

[2]Carter BT, Luke SG. Best practices in eye tracking research. Int J Psychophysiol. 2020 Sep;155:49-62.

Reviewer 2 Report

In this paper the Authors aimed to analyze the correlation between eye movements and asthenopia so as to explore the possibility of using eye-tracking techniques for objective assessment of asthenopia.. Even though the idea this paper is based on may be of interest, I have major concerns:

1.    The paper should be slightly revised to improve its writing.

2.    Abstract section: “This prospective observational study used the computer visual syndrome questionnaire to assess the severity of asthenopia in 93 enrolled college students who complained about asthenopia.” I would suggest to specific the age range.

3.    Methods section:  “This prospective observational study enrolled healthy college students aged between 20 and 30”. I would suggest to insert the number of patients enrolled.

4.    Methods section: “The frequency and intensity of 16 symptoms were assessed across the following three categories: vision disturbance including blurred vision, double vision, difficulty focusing for near vision and colored halos; ocular dis- comforts including burning, itching, feeling of a foreign body, tearing, excessive blinking, eye redness, eye pain and dryness; and extraocular symptom of headache.”. Were the patients examined with a light source? I would suggest to specify and discuss the dark adaptation on the eye movements (https://doi.org/10.1167/tvst.8.6.5).

5.    Methods section, Accommodation : I would suggest to better explain this point. It is confused.

6.    Discussions: I would suggest to better explain the conclusions of this work. The authors seems to stop the discussions with the limitations. I would suggest to include some hypothesis.

Author Response

Point 1: The paper should be slightly revised to improve its writing. 

Response 1: Thanks for the reviewer’s comments. The manuscript has been edited by a language service from MedSci (Certificate was provided).

Point 2: Abstract section: “This prospective observational study used the computer visual syndrome questionnaire to assess the severity of asthenopia in 93 enrolled college students who complained about asthenopia.” I would suggest to specific the age range.

Response 2: Thanks for the reviewer’s comments. The age range of subjects is 20-30. Information was added in the manuscript as:“This prospective observational study used the computer visual syndrome questionnaire to assess the severity of asthenopia in 93 enrolled college students (age 20-30) who complained about asthenopia.” (highlighted in yellow)

Point 3: Methods section:  “This prospective observational study enrolled healthy college students aged between 20 and 30”. I would suggest to insert the number of patients enrolled.

Response 3: Thanks for the reviewer’s comments. Information was added in the manuscript as: “This prospective observational study enrolled 93 healthy college students aged between 20 and 30” (highlighted in yellow).

Point 4: Methods section: “The frequency and intensity of 16 symptoms were assessed across the following three categories: vision disturbance including blurred vision, double vision, difficulty focusing for near vision and colored halos; ocular dis- comforts including burning, itching, feeling of a foreign body, tearing, excessive blinking, eye redness, eye pain and dryness; and extraocular symptom of headache.”. Were the patients examined with a light source? I would suggest to specify and discuss the dark adaptation on the eye movements (https://doi.org/10.1167/tvst.8.6.5).

Response 4: Thank you so much for the valuable advice and reference. Yes, the patients were examined with a light source in our research. This is because we want to explore eye movement in reading task under real life situation, which is almost with a light source. Meantime, the subjects are healthy and young, with no retina disease (AMD or RPD which may cause great influence on vision dark adaption) so the dark adaptation was not included in this research.

Point 5: Methods section, Accommodation : I would suggest to better explain this point. It is confused.

Point 6: Discussions: I would suggest to better explain the conclusions of this work. The authors seems to stop the discussions with the limitations. I would suggest to include some hypothesis.

Response 6: Thanks for the reviewer’s comments. We revised the last paragraph and made the conclusion more clear (highlighted in yellow).