Optical Characterization of a Rotationally Asymmetric Refractive Multifocal Intraocular Lens Compared to a Standard Monofocal One

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper focuses on the optical properties of a rotational asymmetric refracting multifocal intraocular lens (IOL) and a standard single focal IOL. By comparing the optical properties of the two IOL, the researchers found that the multifocal IOL was significantly different from the optical performance of the unifocal IOL.

 Following are some questions for that paper,

1,Figure 3 shows primary spherical aberration variation with optical zone diameter, whereas vertical coma is depicted in Figures 4 (primary vertical coma) and 5 (secondary vertical coma).

In line 163 and line 164, the author says the remaining Zernike polynomials have no significant effect, so what’s the reason for that conclusion?

2,In section 2.2 Optical Bench from line 90 to line94,what’s the reason for author adopt microns (from the third to thirteenth order) to be expressed for the Zernike coefficient values related to the spherical aberration [from Z(4:0) to Z(8:0)]? The same qustion at line 95 about the RMS was studied for 3 mm and 4.5 mm.

Author Response

We would like to express our gratitude to the Reviewer for his/her valuable work in reviewing our manuscript.

Following are some questions for that paper,

1,Figure 3 shows primary spherical aberration variation with optical zone diameter, whereas vertical coma is depicted in Figures 4 (primary vertical coma) and 5 (secondary vertical coma).

In line 163 and line 164, the author says the remaining Zernike polynomials have no significant effect, so what’s the reason for that conclusion?

We have added the nest sentence after lines 163-164:

“ since the RMS values computed considering all Zernike polynomials up to the 10th order for each of the IOLs are almost equal to the RMS values computed with just the aforementioned polynomials (with minor variations from the 3th decimal position onwards)”

2,In section 2.2 Optical Bench from line 90 to line94,what’s the reason for author adopt microns (from the third to thirteenth order) to be expressed for the Zernike coefficient values related to the spherical aberration [from Z(4:0) to Z(8:0)]? The same qustion at line 95 about the RMS was studied for 3 mm and 4.5 mm.

The reason for expressing the Zernike coefficient values in microns is to adhere to the international standards (International Standard ISO-24157). The standards for reporting optical aberrations in human eyes and intraocular lenses consider microns as the unit to be used for aberration reporting (Thibos LR et al. Standards for reporting the optical aberrations of eyes. J Refract Surg. 2002 Sep-Oct;18(5):S652-60. doi: 10.3928/1081-597X-20020901-30). On the other side, to the best of our knowledge, all commercially available instruments for measuring aberrations, both clinically in the human eye, and in vitro in an optical bench, report aberration information in microns. Using microns allows for a precise representation of the aberration magnitudes and aligns our methodology with internationally recognized guidelines.

Regarding the question about selecting 3 and 4.5 mm for aberration reporting, these values are typically used in the literature as they correspond to typical pupil sizes under photopic (3.00 mm) and mesopic (4.5 mm) lighting conditions. In the previous version of the manuscript, we stated that these optical zone values were to be used for studying RMS values. However, these zones have been utilized to also study the coefficient values for isolated Zernike polynomials, and not just RMS values. Therefore, we have made some changes to this sentence.

“Aberrations were studied for 3 mm and 4.5 mm, since those are currently used in the literature as they correspond to typical pupil sizes under photopic (3.00 mm) and mesopic (4.5 mm) lighting conditions”

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Well-written. A more clinically relevant conclusion would have been slightly better (e.g. stressing what the benefits/disadvantages of a the multifocal IOLs could be; one such point was mentioned about degradation of visual outcome by decentration of the multifocal IOL relative to monofocal; perhaps other clinically relevant points may be worth mentioning). 

Author Response

We would like to express our gratitude to the Reviewer for his/her valuable work in reviewing our manuscript.

The central idea of this work is to provide practitioners with precise and comprehensive information on the power and aberrometric profiles of the evaluated intraocular lenses, as laboratories do not typically provide such detailed information. This is not a clinical study reporting visual results on implanted eyes, but the information herein presented has important implications for ophthalmic surgeons. We have pointed some clinically relevant conclusions that can arise in the light of our results:

Lines 231-234:

“With the information of power profiles herein presented, any ophthalmic surgeon can decide to implant a given IOL model with a given nominal addition depending on the patient’s pupil size and distance requirements.”

Lines 241-245:

“On the other hand, providing complete information on the Zernike values for both 3 mm and 4.5 mm apertures could help other researchers to make image simulations of the optical behavior of those lenses implanted in a model eye before actual implantation. Without a complete aberrometric information those simulations are not possible.”

Lines 405-407

“This asymmetrical design of the Acunex multifocal IOLs could be a contraindication in patients with zonular stability issues, making the implantation of the monofocal model more advisable in those cases.”

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The paper is sound but the premise is unusual, in that the authors seem to assess several aberrations orders in commercially available IOL models in order to create a database that can be helped to inform opththalmic care. Perhaps there is a demand for this kind of information (I am not extremely familiar with IOL usage in practice) but it would be good to see the motivation behind the study explained in a more persuasive manner.

Minor comment: a diagram showing the IOL in the quartz cuvette and the technical info such as refractive index of the saline solution should be added

Author Response

We would like to express our gratitude to the Reviewer for his/her valuable work in reviewing our manuscript.

Laboratories do not provide complete aberrometric information of the IOLs they deliver. In fact, some laboratories do not provide any information at all apart of the power and refractive index.

Before a clinical IOL implantation in an actual eye, researchers and clinicians would benefit from simulations to understand what to expect from an IOL implant. These simulations, made in Zemax, Matlab, or any other software, require a complete optical lens characterization to be run. The Modulation Transfer Function (MTF) is one of the best parameters for providing comprehensive optical quality information. MTF can be obtained from aberrometric information, as can the Point Spread Function (PSF) needed to simulate images by convolution. Thus, complete aberrometric information of IOLs is crucial for running these simulations

The following lines have been added at line 241:

“On the other hand, providing complete information on the Zernike values for both 3 mm and 4.5 mm apertures could help other researchers to make image simulations of the optical behavior of those lenses implanted in a model eye before actual implanta-tion. Without a complete aberrometric information those simulations are not possible.”

Minor comment: a diagram showing the IOL in the quartz cuvette and the technical info such as refractive index of the saline solution should be added

Lines 101-102 have been modified:

“To prevent surface deformation and dehydration during measurements, IOLs were immersed in a saline solution with refractive index = 1.334 in a quartz cuvette devoid of aberrations.”

And lines 104-108 and Figure 1 have also been modified:

“Figure 1 shows a picture of the +20.00 D AN6VM IOL as seen inside the NIMO cuvette (left side). A vertical dashed line has been added to the IOL image in Figure 1 to indicate the IOL axis of symmetry along which data was obtained to depict power profiles (left side). A picture of the cuvette containing the lens and positioned for measurement can be seen in the right side of Figure 1.”

 

And figure caption is now:

“Figure 1. Image of the Acunex multifocal lens measured on the optical bench (left side). The near power zone is located at the bottom, while the distance power zone is at the top and centered within the notch. The vertical dashed line symbolizes the axis of symmetry, along which data was collected to illustrate power profiles. Cuvette with the lens inside in measurement position (right).”

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The purpose of this study is to provide laboratory-independent technical information on the Acunex IOL, so the revised paper lack of some highlight points for Applied Sciences.

The decision of rejection mainly based on the figure3 and the conclusion from figure 3,

From Figure 3 we can see the primary spherical aberration of AN6 have significant change with almost 0.3 microns comparing the value of AN6V and AN6VM, the author should further analysis and explain the aberration instead of saying the remaining Zernike polynomials have no significant effect.

Author Response

The purpose of this study is to provide laboratory-independent technical information on the Acunex IOL, so the revised paper lack of some highlight points for Applied Sciences.

The decision of rejection mainly based on the figure3 and the conclusion from figure 3,

From Figure 3 we can see the primary spherical aberration of AN6 have significant change with almost 0.3 microns comparing the value of AN6V and AN6VM, the author should further analysis and explain the aberration instead of saying the remaining Zernike polynomials have no significant effect.

We wish to extend our heartfelt thanks to the reviewer for their thorough and valuable review of our manuscript.

To address the reviewer's comments, we have included a new figure, Figure 4, which shows the third to fifth-order Zernike coefficients, including second and eighth-order spherical aberrations, for an optical zone diameter of up to 5.00 mm for the three IOL models (AN6, AN6V, AN6VM) and for the three nominal powers (+10.00 D, +20.00 D, +30.00 D). Additionally, we have calculated the wavefront error variance for HOA, SA, and coma, and their percentage contributions for the three lenses evaluated at an IOL power of +20.00 D. This information has been included as Table 1.

Table 1. Wavefront error variance and contribution for an optical zone diameter of 3.00 and 4.50 mm for the three IOL models (AN6, AN6V, AN6VM) for the nominal power of +20.00 D

		Wavefront error variance			Contribution wavefront error variance
Zone (mm)	IOL (D)	HOA (µ2)	SA (µ2)	COMA (µ2)	% SA	% COMA
3	AN6	0,00351	0,00336	3,5E-06	96	0
3	AN6V	0,08884	0,00066	0,03723	1	42
3	AN6VM	0,34315	0,00194	0,14969	1	44
4,5	AN6	0,06988	0,06912	2,7E-05	99	0
4,5	AN6V	0,48104	0,00712	0,13796	1	29
4,5	AN6VM	1,84837	0,00334	0,59934	0	32

 mm: milimeters; D: diopter; µ: microns; %: percentage

 

 

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

the revised paper have met the requirements for acceptance.