PONE-D-19-21173

Accuracy of intraocular lens power calculation formulas using a swept-source optical biometer

PLOS ONE

Dear Dr Jung,

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PLOS ONE

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Please, address the issues raised by the reviewers.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: No

Reviewer #4: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This is an interesting study. Although it does not add significant information to the recently published studies on much larger samples, it is the one of the first multiformula comparisons carried out with measurements by the IOLMaster 700.

Please find below some suggestions to improve the paper.

METHODS

• Subgroup analysis: short eyes are usually defined as those with AL <22.0 mm (not 22.5 mm). Please correct and repeat analysis.

• Statistical analysis: in addition to Friedman’s test (to analyze the absolute prediction errors), I would include Repeated Measures ANOVA to compare the arithmetical prediction errors and their variance. This can be useful for both the whole sample and the different subgroups (shallow, medium and deep ACD, etc.), where it may reveal statistically significant differences among the 5 formulas.

• Statistical analysis: since you correctly used it, please cite Cochran’s Q test in the Methods section too.

• Please include errata for the Hoffer Q formula in the references (J Cataract Refract Surg 1993;19:700-712; errata, 1994;20:677; 2007;33:2-3.)

RESULTS

• It is quite hard to believe the Cochran’s Q test was not able to detect any statistically significant difference among the 5 formulas, as – for example – the Hoffer Q achieved only 69.6% of eyes within 0.5D, whereas the Barrett achieved 78.1% with the same prediction error. Please check carefully the statistical analysis once more.

DISCUSSION

• Barrett formula does not belong to 5th generation formulas. Although unpublished and thus largely unknown, it should be classified among 4th generation ones.

• Please compare your results with those reported by Hoffer Q when comparing the IOLMaster 700 to the Lenstar (JCRS 2016;42:1165-1172). They included the Hoffer Q, Holladay 1 and SRK/T formulas and achieved better results. It would be opportune to elaborate on the possible causes of this discrepancy.

• The whole discussion should be reviewed after ANOVA has been applied to the arithmetic prediction errors, as statistically significant differences may arise.

Reviewer #2: Good results that support the conclusion. Reasonable statistical analysis. Correct terminology used. The ideas are clearly expressed in English. A bigger sample size is suggested in future research.

Reviewer #3: I have read the article by Kim et al. The authors have analyzed the accuracy of IOL power calculation formulas using the IOL Master 700.

Comments:

- P3 L53 - what about LCOR?

- P3 L56 - some formulas also use preoperative refraction and age. Moreover, you should state that increasing the number, from the basic which is AL and K

- P3 L63 - be more precise, what formulas in what axial lengths? Is it concordant with the results of your study?

- P5 L108 - short eyes were determined as those having AL<22.5 mm, while long as those having 25.0 mm. As several studies used different cut-off values i.e. 22.0 mm or 26.0 mm choosing these values should be thoroughly explained.

- the group size for some subgroups (e.g. long eyes=16, flat keratometry=16, shallow ACD=20) very small, making an appropriate analysis difficult.

- in the results section you state: "The percentages of eyes within the prediction errors of ±0.25, ±0.50, ±0.75 D, and ±1.00 D were not significantly different among the five formulas using the Cochran Q test (P > 0.050)". However, in the abstract one can find "The Barrett Universal II formula resulted ... in a higher percentage of eyes with prediction errors within ±0.50 D, ±0.75 D, and ±1.00 D." The same in P8 L163

- P8 L164 - present what test was used and the p values.

- P12 L238 as 20 eyes had a shallow ACD, how is it possible that 36.8% eyes (and not 35% or 40%) in this group had a prediction error of ±0.50 D with the Hoffer Q formula

- Figure 3 is difficult analyze. Please consider a more various grayshade scheme or preferably adding colours...

The main limitation of the study is the group size, which is 219 eyes, compared to e.g., 18 501 in the study by Melles et al. Moreover, the novelty of this study is limited. Finally, the conclusions do not reflect the actual findings of the study (low difference between formulas, limited statistical significance)

I would consider publication after the revision.

Reviewer #4: This study evaluated the accuracy of the five intraocular lens (IOL) formulas integrated to a swept-source optical biometer. The manuscript was well written. I would like to add some comments.

1. Page 5, Line 108-111

Provide a reference for the criteria of subgroup classification as follows:

For the subgroup analysis, the AL, preoperative mean keratometry, and ACD (measured

from epithelium to lens) were divided into three subgroups: short (<22.5 mm), medium

(22.5–25.0 mm), and long (>25.0 mm); flat (<42.0 D), medium (42.0–45.0 D), and steep

(>45.0D); shallow (<2.50 mm), medium (2.5–3.5 mm), and deep (>3.5 mm).

2. Page 7, Line 150, Table 1

Please present the mean±SD of each subgroup in AL, K, and ACD.

3. Page 21, Fig.2.

For the MAE, we recommend the box whiskers plot instead of the line. The box whiskers plot can provide more information to the reader.

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Reviewer #1: Yes: Giacomo Savini, MD

Reviewer #2: No

Reviewer #3: Yes: Piotr Kanclerz, MD, PhD

Reviewer #4: No

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PONE-D-19-21173R1

Accuracy of intraocular lens power calculation formulas using a swept-source optical biometer

PLOS ONE

Dear Dr Jung,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

We would appreciate receiving your revised manuscript by Jan 10 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Ireneusz Grulkowski, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (if provided):

Some minor editing of the plot needed as given by the Reviewer 4

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

Reviewer #4: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #4: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #4: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #4: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: (No Response)

Reviewer #4: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Just a minor comment: in table 1, medium axial length is still defined as between 22.5 and 26 mm. Please correct 22.5 and change it into 22

Reviewer #2: Good results that support the conclusion. Reasonable statistical analysis. Correct terminology used. The ideas are clearly expressed in English. A bigger sample size is suggested in future research.

Reviewer #4: We have confirmed the corrections in the manuscript.

Please indicate the minimum and maximum values ​​for the box & whisker plots.

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Reviewer #1: No

Reviewer #2: No

Reviewer #4: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

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Accuracy of intraocular lens power calculation formulas using a swept-source optical biometer

PONE-D-19-21173R2

Dear Dr. Jung,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

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Ireneusz Grulkowski, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #4: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #4: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #4: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #4: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #4: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #4: The manuscript has been modified according to the requirements. This manuscript is expected to give readers useful information.

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Reviewer #4: No