Analysis of the Effective and Actual Lens Position by Different Formulas. Postoperative Application of a Ray-Tracing-Based Simulated Optical Model
, Laura Remón MartÃn 1, Iván Pérez Escorza 1 and Francisco Javier Castro Alonso 2,3
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsIn the manuscript “Postoperative application of a ray tracing-based simulated optical model”, the authors present the results of an interesting study comparing the effective lens position and intraocular lens power obtained by different formulas from preoperative data, and that after cataract surgery.
Some modifications and suggestions are indicated.
Title
As a suggestion, the title could be modified, since it does not reflect clearly the scope of the study.
Methods
Line 66. - In relation with sample size, how it was calculated? It is important to warrant validity of statistical results.
Line 98. - A typographic error is observed: … the IOLP and ELP were predicted…
Line 96 and 100: “A-Constant” or “A Constant”?
Line 147. - More specific data to R-Commander statistical software should be included.
Line 145 to 153. - Some confusion in relation with statistical analysis is observed, since paired-t test is not a correlation one, so, it don’t assess relationships; moreover, it can be observed that no correlation analysis was done according to results section. Paired-t test show specific statistical differences between each variable. Bland–Altman describes the correlation or similarity between two variables, just representing averages versus differences. Please, clarify all these concepts.
Results
Line 158. - Why right or left eyes numbers are indicated? Explain
Line 159, table 1. - It could be another option to include demographics patient data in the text, to just include in table 1 pre and postoperative descriptive data of each parameter.
Line 160. - Include statistical test used together with p-value, both here as well as in all analysis.
Line 179. - Orthographical mistake: … differences were found…
Include statistical test used together with p-value.
Line 181. - Table 2 don’t display agreement but differences.
Line 192 and table 3.- ALP and ALPideal difference was checked later. Why difference between ALP and each of the calculated values was not analyzed? Could it be useful?
Discussion
Just some general observations:
- Very long sentences are used all along discussion, which make it difficult to understand.
- Do not include p-values
Conclusions
Line 298. - Singular or plural tense? Integrating instead of integrate; Do not include p-values
Comments on the Quality of English Language
In the manuscript “Postoperative application of a ray tracing-based simulated optical model”, the authors present the results of an interesting study comparing the effective lens position and intraocular lens power obtained by different formulas from preoperative data, and that after cataract surgery.
Some modifications and suggestions are indicated.
Title
As a suggestion, the title could be modified, since it does not reflect clearly the scope of the study.
Methods
Line 66. - In relation with sample size, how it was calculated? It is important to warrant validity of statistical results.
Line 98. - A typographic error is observed: … the IOLP and ELP were predicted…
Line 96 and 100: “A-Constant” or “A Constant”?
Line 147. - More specific data to R-Commander statistical software should be included.
Line 145 to 153. - Some confusion in relation with statistical analysis is observed, since paired-t test is not a correlation one, so, it don’t assess relationships; moreover, it can be observed that no correlation analysis was done according to results section. Paired-t test show specific statistical differences between each variable. Bland–Altman describes the correlation or similarity between two variables, just representing averages versus differences. Please, clarify all these concepts.
Results
Line 158. - Why right or left eyes numbers are indicated? Explain
Line 159, table 1. - It could be another option to include demographics patient data in the text, to just include in table 1 pre and postoperative descriptive data of each parameter.
Line 160. - Include statistical test used together with p-value, both here as well as in all analysis.
Line 179. - Orthographical mistake: … differences were found…
Include statistical test used together with p-value.
Line 181. - Table 2 don’t display agreement but differences.
Line 192 and table 3.- ALP and ALPideal difference was checked later. Why difference between ALP and each of the calculated values was not analyzed? Could it be useful?
Discussion
Just some general observations:
- Very long sentences are used all along discussion, which make it difficult to understand.
- Do not include p-values
Conclusions
Line 298. - Singular or plural tense? Integrating instead of integrate; Do not include p-values
Author Response
Title.
Comments 1: As a suggestion, the title could be modified, since it does not reflect clearly the scope of the study.
Response 1: [We agree with the referee that the current title does not reflect the scope of the study. We have changed it to:
Analysis of the effective and actual lens position by different formulas. Postoperative application of a ray tracing-based simulated optical model.]
Methods.
Comments 2 - Line 66: In relation with sample size, how it was calculated? It is important to warrant validity of statistical results.
Response 2: [We agree with the reviewer that this information is very useful for ensuring the validity of the statistical results. We have added a new paragraph with this information on line 84:
“The sample size was derived based on calculations evaluation the optimization of ALP to achieve emmetropia [18]. The same methodology applied to the current work suggested that a sample size of at least 16 participants would yield 90% power to optimize the position of the IOL and the refractive error at the 0.05 significance level.”
[18] Castro FJ, Bordonaba D, Piñero DP, et al. Predictive value of intracrystalline interphase point measured by optical low-coherence reflectometry for the estimation of the anatomical position of an intraocular lens after cataract surgery. J Cat-aract Refract Surg 2019, 45, 1294-1304.
Comments 3 - Line 98: A typographic error is observed: … the IOLP and ELP were predicted…
Response 3: [We apologize for the oversight. The typographic error has been corrected.]
Comments 4 - Line 96 and 100: “A-Constant” or “A Constant”?
Response 4: [We apologize for this inconsistency. We have corrected the text to ensure that "A-Constant" is used consistently throughout the manuscript.]
Comments 5 - Line 147: More specific data to R-Commander statistical software should be included.
Response 5: [We have added the version of the software to the manuscript. Specifically, the version 4.1.1 of R-Commander has been included on line 156.]
Comments 6 - Line 145 to 153: Some confusion in relation with statistical analysis is observed, since paired-t test is not a correlation one, so, it doesn’t assess relationships; moreover, it can be observed that no correlation analysis was done according to results section. Paired-t test show specific statistical differences between each variable. Bland–Altman describes the correlation or similarity between two variables, just representing averages versus differences. Please, clarify all these concepts.
Response 6: [You are correct in pointing out that the type of statistical test used was not clearly specified in the original text. We have made the necessary corrections in the manuscript. The revised text now reads:
"Subsequently, a paired t-test was used to compare the means of related samples, identifying significant differences between them."
The paragraph referring to the Bland-Altman plots has also been revised:
“Bland-Altman plots were used to explore the correlation between ELP, ALP and RE measurements.”
We have also corrected other instances throughout the text where the concept of correlation was incorrectly applied.]
Results.
Comments 7 - Line 158: Why right or left eyes numbers are indicated? Explain
Response 7: [We agree with the reviewer that it is not important to indicate the numbers for right and left eyes in this context. We have removed this information from the text and from Table 1.]
Comments 8 - Line 159, table 1: It could be another option to include demographics patient data in the text, to just include in table 1 pre and postoperative descriptive data of each parameter.
Response 8: [We agree with the reviewer that including patient demographic data in the text while limiting Table 1 to pre- and postoperative descriptive data for each parameter will help clarify the results. We have made these adjustments accordingly.]
Comments 9 - Line 160: Include statistical test used together with p-value, both here as well as in all analysis.
Response 9: [We have added the specific statistical test next to each p-value throughout the manuscript. The format used is (t-test, p-value=XX).]
Comments 10 - Line 179 : a) Orthographical mistake: … differences were found… b) Include statistical test used together with p-value.
Response 10: a) We apologize for the orthographical mistake. The error has been corrected to “… differences were found…”.
- b) We have added the specific statistical test next to each p-value throughout the manuscript.
Comments 11 - Line 181: Table 2 don’t display agreement but differences.
Response 11: [Thank you for your comment. We have revised the text to clarify that Table 2 reflects differences rather than agreement.]
Comments 12 - Line 192 and table 3: ALP and ALPideal difference was checked later. Why difference between ALP and each of the calculated values was not analyzed? Could it be useful?
Response 12: Thank you for your query. The difference between ALP and each calculated value of ELP does not provide clinically relevant insights. ALP directly represents the anatomical axial position, whereas ELP is a calculated value intended to optimize alignment with biometric data, IOL power, and postoperative refraction. This calculation involves assumptions, such as the conversion from corneal curvature to corneal power using a keratometer index, which can introduce systematic errors in corneal power estimation.
In essence, while ALP serves as a straightforward anatomical measurement, ELP serves a more abstract role in optimizing postoperative outcomes. Considering these factors, we have determined that conducting such an analysis would not be particularly informative.
Discussion.
Comments 13: Just some general observations: Very long sentences are used all along discussion, which make it difficult to understand. Do not include p-values
Response 13: [We have revised and modified the text to shorten the sentences and improve clarity. Additionally, we have removed the p-values as per your recommendation.]
Conclusions.
Comments 14 - Line 298: Singular or plural tense? Integrating instead of integrate; Do not include p-values
Response 14: [The sentence now reads: "A customized ray-tracing eye model was proposed, integrating parameters such as anterior and posterior corneal topography, biometry, and IOL position." We have removed all p-values from the conclusions as per your suggestion.].
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsPage 1 line 43 is the statement "these formulas are not public" correct? in the conclusions they are referred to as open source with one exception.
Page 5 lines 177-179 please consider showing the results of using each of the vergence formulas in a table.
Page 5 Table 2 and Page 6 Table 3: Please comment on why some p-values corresponding to IOLP Haigis are so close to 0.
Page 7, Fig 2 please put a minus in front of the red 0.47 limit on the plot
Page 7, Fig 3 caption please avoid "as a function" to describe what seems to be a correlation plot.
Page 8, lines 232-236 please explain why it is relevant to compare against a study that looks at a different IOL model.
Page 8, line 258 please explain what is meant by "It was found". (e.g. by whom?)
Finally, please rewrite the sentences in abstract starting with "to ..." and add verbs in the past tense where necessary in other sentences; at the moment it reads like a bullet list.
Comments on the Quality of English LanguageThe abstract needs some attention to make the sentences flow but very good otherwise.
Author Response
Comments 1 - Page 1 line 43 is the statement "these formulas are not public" correct? in the conclusions they are referred to as open source with one exception.
Response 1: [We agree with the referee that the statement in the introduction section is confusing. We have added that new generation formulas are not publicly available, and thus their estimated ELP remains unknown.]
Comments 2 - Page 5 lines 177-179 please consider showing the results of using each of the vergence formulas in a table.
Response 2: [We have added the average IOLP ± SD calculated with Hoffer Q, Holladay I, SRK/T and Haigis to Table 2].
Comments 3 - Page 5 Table 2 and Page 6 Table 3: Please comment on why some p-values corresponding to IOLP Haigis are so close to 0.
Response 3: [We have revised the annotation to avoid confusion for the reader. The p-values corresponding to IOL power (Haigis) are reported as p<0.001* due to the significant differences observed when compared with the Barrett Universal II model.]
Comments 4 - Page 7, Fig 2 please put a minus in front of the red 0.47 limit on the plot.
Response 4: [Thank you for your suggestion. We have added the minus sign in front of the red 0.47 limit on the plot.]
Comments 5 - Page 7, Fig 3 caption please avoid "as a function" to describe what seems to be a correlation plot.
Response 5: [We have changed "as a function" to "vs" in the caption of Figure 3: a) REOBJ vs ΔALP (mm). (b) RESUBJ vs ΔALP (mm).]
Comments 6 - Page 8, lines 232-236 please explain why it is relevant to compare against a study that looks at a different IOL model.
Response 6: [We have rewritten these lines to explain why it is relevant to compare with the present study. In both studies, the same methodology and platform design of the IOL (Alcon) were used. We have added this information:
“In a previous study using the same methodology, Castro et al [18] measured the postoperative ALP with Lenstar in patients implanted with the SN60WF IOL. Their results were very similar to our findings, with an ALP of 4.50 ± 0.33 mm obtained with the Clareon IOL. Both IOLs have the same platform design (Alcon Laboratories, Inc.)]”
Comments 7 - Page 8, line 258 please explain what is meant by "It was found". (e.g. by whom?)
Response 7: [It was a mistake. We have rewritten the sentence as: “No statistically significant differences were identified between the IOLPs calculated using third-generation formulas and Haigis”.]
Comments 8: Finally, please rewrite the sentences in abstract starting with "to ..." and add verbs in the past tense where necessary in other sentences; at the moment it reads like a bullet list. The abstract needs some attention to make the sentences flow but very good otherwise.
Response 8: [We have rewritten the sentences in abstract section.]
Author Response File: Author Response.docx
Reviewer 3 Report
Comments and Suggestions for Authorsline 19 - "being the difference -0.04 ± 0.45 mm" - improper phrasing, please rephrase
Lines 234-235 - actually the difference found by Castro is about 50% larger than the one found in this study (0.65)
R2 of 0.46, respectively 0.67 indicates a good correletion. While it is not very useful for small deltaALP (for instance, figure 3a shows eyes with zero delta ALP may have RE OBJ from -0.6 to +0.6), it is important to highlight the fact that eyes with large delta ALP (-1, +1.25 mm) will also have large RE OBJ and especially large RE SuBJ, up to 1 diopter
lines 301-302 " A significant cor- 301 relation between ΔALP (ΔALP=ALP- ALPIDEAL) and RESUBJ was found" - you could also add REOBJ
Author Response
Comments 1 - Line 19: "being the difference -0.04 ± 0.45 mm" - improper phrasing, please rephrase.
Response 1: [We have rephrased this sentence].
Comments 2 - Lines 234-235 : actually the difference found by Castro is about 50% larger than the one found in this study
Response 2: [To clarify concepts, we have added the actual study data to the discussion (line 246). In Castro's study, the difference between ELP SRK/T and ALP is 1.04 mm, while in our study, the difference between ELP SRK/T (5.78 mm) and ALP (4.53 mm) is 1.25 mm, indicating consistency. The following paragraph has been added to the discussion for clarification:
“Moreover, Castro et al. [18] identified a 1.04 mm difference between ELP and ALP when using the SRK/T formula, a result that aligns with the 1.25 mm difference ob-served in our current study.” ]
R2 of 0.46, respectively 0.67 indicates a good correlation. While it is not very useful for small delta ALP (for instance, figure 3a shows eyes with zero delta ALP may have RE OBJ from -0.6 to +0.6), it is important to highlight the fact that eyes with large delta ALP (-1, +1.25 mm) will also have large RE OBJ and especially large RE SuBJ, up to 1 D.
Response 2: [We agree with the referee that it is important to note this fact. We have added the following sentence in line 219:
It is important to highlight the fact that eyes with large delta ALP (-1.00, +1.25 mm) will have large REOBJ and especially large RESUBJ, up to 1.00 D.]
Comments 3 - Lines 301-302 : " A significant correlation between ΔALP (ΔALP=ALP- ALPIDEAL) and RESUBJ was found" - you could also add REOBJ.
Response 3: [We have added this information in lines 296-297]
Author Response File: Author Response.docx
