Accommodative Relaxation by Extending the Viewing Distance through the Simple Optical Design of a Double-Mirror System
Round 1
Reviewer 1 Report
The submitted manuscript reports the study on accommodative relaxation by extending the viewing distance through the optical design of a double-mirror system. The authors claim that the proposed simple optical system may improve eye fatigue and delay the progression of myopia. The authors examined 32 people with an average age of 20.8. The research brings some results related to eye strain caused by digital devices. Generally, the presented study seems to be interesting for readers of the Applied Sciences.
In the revised version authors should provide more details on the proposed system, i.e. the parameters of the concave and convex mirrors. Are there any optical defects of the mirrors that could interrupt the image view and the results? A short discussion is needed.
Author Response
Dear reviewer,
Thank you for the precious suggestions on the manuscript, “Accommodative relaxation by extending the viewing distance through the simple optical design of a double-mirror system,” and we have made substantial revision to the manuscript based on the comments, as the details below.
In the revised version authors should provide more details on the proposed system, i.e. the parameters of the concave and convex mirrors. Are there any optical defects of the mirrors that could interrupt the image view and the results? A short discussion is needed.
Response:
The image observed by a user viewing a target of 10 mm X 10 mm, which is at the right-bottom side of the double-mirror system, can be analyzed by the optical software, LightTools, illustrated in Fig. 2 [21]. In the simulation, the concave mirror is of 140 mm wide and 70 mm high with a curvature radius of 706.7 mm in the y-z plane and 745 mm in the x-z plane. The convex mirror is also of 140 mm wide and 70 mm high with a spherical curvature radius of 706.7 mm. When viewing the target through the double-mirror system, both eyes rotate to a vergence angle of 1.62° and can observe an enlarged image at 2285 mm with a size of 0.254 mm wide and 0.195 mm high, as shown in Fig. 3a and 3b for the left and right eyes, respectively. A direct viewed image for the same target at 2285mm is 0.075 mm wide and shown in Fig. 3c for comparison. The simulations indicate that the magnification of the double system is around 3.386 X along the horizontal direction and 2.6 X along the vertical direction. In fact, these values are obtained by assuming the pupil distance to be 65 mm and can vary significantly for different pupil distances. Besides the magnification difference between the horizontal and the vertical directions needs to be improved for further applications.
Fig. 2 Optical layout of the double-mirror system built in the optical software, LightTools.
Fig. 3 Simulated images at the retina. The viewed images by (a) the left eye and (b) the right eye though the double-mirror system. (c) A direct viewed image for a target at 2285mm.
Kind regards
With above responses and substantial revisions, please kindly consider its publication in Applied sciences. Thank you for your kind consideration and assistance.
Sincerely,
Shuan-Yu Huang
Professor,
School of Optometry,
Chung Shan Medical University,
Author Response File: 
Author Response.docx
Reviewer 2 Report
The authors to present the acommodative relaxation by extending the viewing distance through the simple optical design of a doble mirror system
Major concerns
#1 The sample analyzed is small.
#2 The age of the sample is high to speak of myopia control, this statement would need to be better justified.
#3 The methodology should be better described, what parameters have been measured and how.
#4 The changes in the accommodation of the participants are not clear, they should provide a table with the values ​​using and not using the device described.
#5 Little little bibliography provided.
Author Response
Dear reviewer,
Thank you for the precious suggestions on the manuscript, “Accommodative relaxation by extending the viewing distance through the simple optical design of a double-mirror system
,” and we have made substantial revisions to the manuscript based on the reviewer’ comments, as the details below.
#1 The sample analyzed is small.
Response:
The 32 subjects of this study were recruited from the Chung Shan Medical University and the Da-Yeh University. The inclusion criteria were as follows: those who had no prior eye or systemic diseases, those with a spherical diopter ranging from 0D to -5.00D, those with an astigmatism diopter ≥-2.00D, those with binocular visual acuity ≥ 0.1 logMAR, and those with normal binocular vision. There were 43 participants, 32 of them met the criterias, and 11 were excluded. The experimental process was quite time-consuming, especially for an examination of the basic visual function. With the limitation of the experimental resources, we were currently unable to obtain a large number of samples. Despite the number of samples we analyzed were not large, the significant differences were found in accommodative response (p <0.001) and pupil size (p<0.001) between gazing at 0.4m and 2.285m (through double-mirror system) in this stud. For the next experiment, we will definitely recruit more subjects.
#2 The age of the sample is high to speak of myopia control, this statement would need to be better justified.
Response:
In the end of the introduction, we have corrected as “In this study, the accommodative response can be reduced for the subjects aged between 18 to 22 years old, we expect that the accommodative relaxation can be also achieved for school children, furthermore, it may be applied to slow down the progression of myopia and to mitigate the problems caused by near work.”
By the end of the conclusion, we have corrected as ”In this study, the accommodative response of the subjects aged from 18 to 22 years old can be reduced by the simple optical design. We expect that the accommodative relaxation can be also achieved for school children, moreover, it may have the potential application in slowing down the progression of myopia and to mitigate the problems caused by near work.”
#3 The methodology should be better described, what parameters have been measured and how.
Response:
In the research process, we described as
Research Process
The experimental procedure included the following two steps: The first step was an examination of the basic visual function. Each subject received an initial examination of refractive status by an open-field autorefractor, visual acuity by a chart-projector, phoria by a cover test, stereoscopic vision by a fly-stereopsis test, etc. After the basic examination, disposable contact lenses were provided to the subjects with a corresponding refractive error (Cooper Vision, water content: 55%, base arc: 8.6 mm, diameter: 14.2 mm).
The second step was to measure the subjects’ dynamic accommodative responses and pupil sizes. The indoor brightness affects the pupil size. In the dark state, the pupil size is larger. Because this optical design is for reading purposes, we measured the accommodative responses and pupil size in the state of brightness. The luminance of the laboratory is about 588 lux (measured by spectral light meter (optimum SRI 2000)). Two viewing distances were set for the experiment: (1) the subjects gazed at a real object that was placed at a distance of 0.4 m; and (2) they gazed at a virtual image that was located at a distance of 2.285 m through the double-mirror system. An open-field autorefractor (Grand Seiko WAM WR-5500) was used to measure the dynamic accommodative responses and pupil sizes of the subjects. Each detection time was 30 seconds, and the average value of the three measurements was taken. Only the data of the right eye were measured in the experiment, and the subjects were required to cover their left eye with a occlude covering. During the detection, the subjects were allowed to blink naturally, but they were asked to maintain their gaze at the target. The unit of the accommodative response is a diopter (D), and the unit of the pupil size is mm.
Data Analysis
The dynamic accommodative responses and the pupil sizes of the right eye were recorded on the computer. All the data were analyzed by SPSS Statistics 21.0, and an independent sample t-test and paired samples t-test were conducted for statistical analysis.
#4 The changes in the accommodation of the participants are not clear, they should provide a table with the values using and not using the device described.
Response:
The accommodative response varies with the viewing distance in these three ways is presented in Table. 2. When the subjects are looking directly at the real object and seeing the image through a single plane mirror, the accommodative response decreases with the increase of the viewing distance from 0.4 m to 1.6m. When the viewing distance reaches 2.285m, the accommodative response of the above two observation methods is very close to the accommodative response obtained by the double mirror system, which is about 0.11 ± 0.05D.
Table. 2. The accommodative response varies with the viewing distance in the different ways
|
Accommodative Response (D) |
Viewing Distance (m) |
|||||
|
0.4 |
0.6 |
0.8 |
1.2 |
1.6 |
2.285 |
|
|
Directly seeing target |
1.69 ± 0.31 |
0.74 ± 0.22 |
0.48 ± 0.09 |
0.37 ± 0.08 |
0.14 ± 0.05 |
0.11 ± 0.04 |
|
Single plane mirror |
1.97 ± 0.59 |
1.20 ± 0.31 |
0.83 ± 0.16 |
0.26 ± 0.06 |
0.17 ± 0.03 |
0.16 ± 0.04 |
|
Double-mirror system |
x |
x |
x |
x |
x |
0.11 ± 0.05 |
Note: The viewing distance of the double-mirror system is fixed, there is only one
accommodative response at 2.285 m.
#5 Little little bibliography provided.
Response: We have added additional 10 references in the manuscript as follows:
|
2. Demir, P.; Baskaran, K.; Theagarayan, B.; Gierow, P.; Sankaridurg, P.; Macedo, A.F. Refractive error, axial length, environmental and hereditary factors associated with myopia in Swedish children. Clinical and Experimental Optometry. 2021, 2, 1. 3. Guan, H.; Yu, N.N.; Wang, H.; Boswell, M.; Shi, Y.; Rozelle, S.; Congdon, N. Impact of various types of near work and time spent outdoors at different times of day on visual acuity and refractive error among Chinese school-going children. Plos One. 2019, 14(4), 1. 4. Deng, L.; Gwiazda, J,; Thorn. Children’s refractions and visual activities in the school year and summer. Optometry and Vision Science. 2010, 87(6), 406. 5. Hagen, L.A.; Gjelle, J.V.B.; Arnegard, S.; Pedersen, H.R.; Gilson, S.J.; Baraas, R.C. Prevalence and possible factors of myopia in Nnorwegian adolescents. Scientific Reports. 2018, 8(13479), 1. |
|
8. Lee, Y.Y.; Lo, C.T.; Sheu, S.J.; Lin, J.L. What factors are associated with myopia in young adults? A Survey Study in Taiwan Military Conscripts. Investigative Ophthalmology & Visual Science. 2013, 54(2), 1026. |
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9. Mutti, D.O.; Mitchell, G.L.; Moeschberger, M.L.; Jones, L.A.; Zadnik, K. Parental myopia, near work, school achievement, and children’s refractive error. Investigative Ophthalmology & Visual Science. 2002, 43(12), 3633. 10. Saw, S.M.; Hong, R.Z.; Zhang, M.Z.; Fu, Z.F.; Ye, M.; Tan, D.; Chew, S.J. Near-work activity and myopia in rural and urban schoolchildren in China. Journal of Pediatric Ophthalmology & Strabismus. 2001, 38(3), 149. 11. García-Gen, E.; Penadés, M.; Mérida, S.; Desco, C.; Araujo-Miranda, R.; Navea,A.; Bosch-Morell, F. High Myopia and the Complement System: Factor H in Myopic Maculopathy. J. Clin. Med. 2021, 10(12), 2600. doi.org/10.3390/jcm10122600. |
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16. Mazyed Alsaqr, A.; Alshareef, H.; Alhajri, F.; Abusharha, A.; Fagehi, R.; Alharbi, A.; Alanazi, S. Accommodative Response in Patients with Central Field Loss: A Matched Case-Control Study. Vision 2021, 5(3), 35. doi.org/10.3390/vision5030035. 21. LightTools, https://www.synopsys.com/optical-solutions/lighttools.html |
Kind regards
With above responses and substantial revisions, please kindly consider its publication in Applied sciences. Thank you for your kind consideration and assistance.
Sincerely,
Shuan-Yu Huang
Professor,
School of Optometry,
Chung Shan Medical University,
Author Response File: Author Response.docx
