Laser Vision Correction for Regular Myopia and Supracor Presbyopia: A Comparison Study

Round 1

Reviewer 1 Report

This study aims at evaluating the efficacy and safety of femto-presbyLASIK as refractive surgical correction for presbyopia. By comparing the visual outcomes of presbyLASIK with those of standard myopia femto-LASIK, the authors endorse the effectiveness of presbyLASIK, and further proposed a set of more specific indications for the surgery. Overall, the analysis is carefully performed and data properly interpreted. I have only the following minor points that the authors can consider commenting on or discussing in more detail. 

In [Methods], please specify which type of statistical analysis is employed, and include p-value for statistical significance in the results. Typo: Table 1 “Supracore” should be “Supracor” In [3.4. Corneal curvature change], Fig. 3 legends state that “Presbyopia treatments (b) showed a better match than (a) myopia” but in body text “myopic corrections show a good match between planned and achieved spherical correction” and “presbyopia treatments achieve a steeper central cornea than the planned spherical correction”. Please clarify the confusion. Also in [Fig. 3], the axes need to be labeled. [L172-176] the following sentences are duplicated: “In addition to this criterion… None of the eyes in this study developed postoperative ectasia.” It would be interesting if the authors can discuss why astigmatism correction is not working in the current settings. Was it due to the different analysis employed (if the Alpins method vector analysis showed more promising outcomes, it would be helpful to include that data in the manuscript as well); or was it caused by surgically induced astigmatism?

Author Response

Thank you very much for the very valuable comments of the reviewer. The work has gotten so much better.

 

[…] In [Methods], please specify which type of statistical analysis is employed, and include p-value for statistical significance in the results […]

Thank you, that is an excellent hint that has been forgotten. Two-tailed Student t-test was used for calculating the parametric datas and for the nonparametric test the Wilcoxon signed rank test was used. The level of significance was set at p < 0.05.

 

[…]Typo: Table 1 “Supracore” should be “Supracor” […]

Thanks for pointing out, the wording was changed accordingly

 

[…]In [3.4. Corneal curvature change], Fig. 3 legends state that “Presbyopia treatments (b) showed a better match than (a) myopia” but in body text “myopic corrections show a good match between planned and achieved spherical correction” and “presbyopia treatments achieve a steeper central cornea than the planned spherical correction”. Please clarify the confusion. […]

Thank you very much for the advice. It gives us the opportunity to express it more clearly. The top plot (b) in Figure 3 shows that the presbyopia corrections showed a better match between planned and achieved spherical correction (y=0.67x-0.09, R²=0.93), than did the myopia corrections (see Figure 3 a) (y=0.45x-1.22, R²=0.47). We have adapted the text in the paper accordingly.

 

[…]Also in [Fig. 3], the axes need to be labeled. […]

Done. Thank you very much for the remark.

 

[…][L172-176] the following sentences are duplicated: “In addition to this criterion… None of the eyes in this study developed postoperative ectasia.” […]

Thank you, duplication was removed

 

[…]It would be interesting if the authors can discuss why astigmatism correction is not working in the current settings. Was it due to the different analysis employed (if the Alpins method vector analysis showed more promising outcomes, it would be helpful to include that data in the manuscript as well); or was it caused by surgically induced astigmatism? […]

That is an important point. Thank you very much for the remark. We reflected in the manuscript discussion section that the manifest refraction assessments did not support the topography results. Hence, we could assume the topography data to be not accurate enough. However, we did not have the data sets at hand to investigate this further. A future study on repeatability and accuracy of cylinder measurement could be important. We have expanded the text accordingly in the paper.

Reviewer 2 Report

Interesting paper on two commonly used laser treatment techniques for myopia and presbyopia. Well written and with some new aspects.

 

Comments:

Could you please give us the time frame of the study?

Where was the surgery performed and by who?

What was the follow-up time? At what time point were the results collected?

Can you provide the pre-  and postoperative refraction?

What was the reason for the unchanged UCVA in 4 patients? especially in the myopia group?

Author Response

Many thanks for the very helpful inputs. The paper has become much better. […]Could you please give us the time frame of the study?[…]

Thank you for the remark! All surgery procedures were performed between January 2014 and February 2015. We have inserted it accordingly in the text.

[…]Where was the surgery performed and by who?[…]

All surgery procedures were performed by an experienced surgeon (BP) at the Eye Clinic ORASIS. We have added this note in the paper.

[…]What was the follow-up time? At what time point were the results collected?[…]

Preoperative assessment was one week before the surgery. Postoperative assessment was three months after the operation day. This was reflected in the manuscript, accordingly.

Can you provide the pre- and postoperative refraction?

Thank you very much for the hint, the work gains in precision. Pre- and postoperative manifest refraction, was assessed before and after surgery. These data were added to the beginning of the results section of the manuscript.

What was the reason for the unchanged UCVA in 4 patients? especially in the myopia group?

In 2 Supracor eyes of 2 different patients, a slight undercorrection could be seen in the non-dominant eye, which led to no improvement of UCVA. The dominant eye of these patients was perfect regarding target refraction and UCVA.

In both myopic eyes of 2 different patients with no improvement in UCVA in one eye, initial visual acuity was already quite high (0.63). In both cases there was a slight undercorrection and consequently there was no improvement of UCVA. Again, the opposing eye reached the target refraction and UCVA.

In all affected eyes the target refraction could be achieved after re-treatment and UCVA improved accordingly.

Thank you very much for the information. We have extended the corresponding part of the paper.