Comparison of two one-piece acrylic foldable intraocular lenses: Short-term change in axial movement after cataract surgery and its effect on refraction.

PURPOSE: To compare the change in intraocular lens (IOL) axial movement, corneal power, and postoperative refraction of eyes implanted with two different single-piece, open loop, acrylic foldable IOLs with planar-haptic design: one IOL with hinges vs. one IOL without hinges. The role of IOL axial movement on short-term refractive shift after cataract surgery was also evaluated.
METHODS: This retrospective comparative study enrolled consecutive patients who had phacoemulsification with aspheric IOL implantation. The IOL depth (the distance from corneal endothelium to IOL surface) and corneal power were measured via anterior-segment optical coherence tomography at 4 days and 1 month postoperatively. The changes in axial movement of the IOL, corneal power, and manifest refractive spherical equivalent (MRSE) were compared among groups, and the correlations between each lens were evaluated.
RESULTS: IOL with hinges was implanted in 42 eyes of 42 patients and IOL without hinges was implanted in 42 eyes of 42 patients. The change in axial movement between 4 days and 1 month was significantly smaller in the IOL with hinges group than in the IOL without hinges group (p < 0.001). The axial movement of IOL with hinges did not correlate with the MRSE change; however, the forward shift of IOL without hinges correlated with the myopic refractive change (Pearson r = 0.62, p < 0.001).
CONCLUSION: The postoperative axial movement of IOL was more stable in the IOL with hinges group than the IOL without hinges group between 4 days and 1 month after cataract surgery. Even though the two study IOLs with planar-haptic design are made of similar acrylic materials, other characteristics such as hinge structure may affect IOL stability in the bag.

Introduction

Postoperative intraocular lens (IOL) position can affect postoperative refraction, and the gap between actual and target refraction remains a major concern in cataract surgery [1, 2]. IOL characteristics play an important role in determining postoperative lens position. Although previous studies have compared postoperative axial movement of single- and three-piece IOLs, with the single-piece IOLs having less axial movement and resulting in more stable refraction [3-8], short-term myopic changes in refraction from one day to one month after cataract surgery with implantation of single-piece acrylic IOLs were recently reported [9, 10]. Despite the substantial number of IOL models on the market and the popularity of single-piece acrylic IOLs, little is known about differences in postoperative axial movement between one-piece IOLs with planar-haptics from different manufacturers and its effect on the postoperative refraction.

In vitro compression assessments have demonstrated that there is a difference in the axial movement of the IOL optics when one-piece IOLs are designed with planar haptics [11-14]. Hence, we hypothesized that the hinge design, which may affect the axial movement of the IOL optics, is partially responsible for stability of the IOL position.

The purpose of this study was to compare the short-term axial movements of two types of IOLs using anterior-segment optical coherence tomography (AS-OCT). Both IOLs have a similar material (hydrophobic acrylic), 1-piece open loop, and planar haptics; however, both lenses have different haptics design. In addition, we evaluated the role of IOL position shift on refractive change after cataract surgery.

Methods

This was a retrospective, observational, comparative, single-center study of all patients who had undergone uncomplicated cataract surgery at the National Hospital Organization, Tokyo Medical Center, Tokyo, Japan, between December 2015 and February 2017. The study was approved by the institutional review board of the National Hospital Organization, Tokyo Medical Center; Tokyo, Japan, and was conducted in accordance with the tenets of the Declaration of Helsinki. Each patient provided written consent for their medical records to be used in this study.

Only eyes undergoing their first cataract surgery were included. Patients were excluded if they had previous ocular surgery, history of ocular trauma, presence of significant ocular comorbidities, unreliable preoperative biometric measurements, IOL implantation outside the capsular bag, dislocated IOL, intraoperative or postoperative complications, or corrected distance visual acuity (CDVA) after cataract surgery less than 20/30.

All surgical procedures were performed under topical anesthesia by the same experienced surgeon (TN). First, a continuous curvilinear capsulorrhexis measuring approximately 5.0 mm in diameter was accomplished using a bent needle. Subsequently, a clear cornea temporal self-sealing 2.2-mm incision was made, followed by phacoemulsification and in-the-bag unilateral or bilateral IOL implantation of either an IOL with hinges (AcrySof® IQ Toric IOL [Alcon Vision, LLC; Fort Worth, Texas]) or an IOL without hinges (Vivinex™ iSert® XY-1 IOL [Hoya Corporation; Tokyo, Japan]). Both of the IOLs have 13.0 mm overall diameter, 6.0 mm optic diameter, and planar haptics designs that have a 0-degree angle, whereas IQ Toric IOL has a specific flexible hinge design (Fig 1). The same ophthalmic viscoelastic device (Opegan Hi, Santen Pharmaceutical, Osaka, Japan) was used for all surgeries. The I/A tip was inserted behind the IOL optic and the posterior chamber was directly irrigated and cleaned.

Fig 1

Optic and haptic configurations of (a) IOL with hinges and (b) IOL without hinges. While both of IOLs have planar haptics designs with a 0-degree angle, the haptics of the IOL with hinges (c) are constricted (i.e. flexible hinge design, black arrows) and the haptics of the IOL without hinges (d) are straight.

Preoperative axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and keratometry (K) were measured using the swept-source OCT-based biometer OA-2000 (Tomey Corporation, Nagoya, Japan). The corneal real power including anterior and posterior corneal refractive powers, corneal thickness and IOL depth, which is the distance from corneal endothelium to IOL surface along the vertex normal (Fig 2), were automatically measured using a swept-source AS-OCT (CASIA2, SS-2000; Tomey Corp; Aichi, Japan) with a super-luminescent diode light source (1310 nm wavelength) and a scan speed of 50,000 A-scans/second. To precisely measure a true change in IOL position or in corneal curvature, three repeated measurements were obtained during a single visit by one technician. The exported data is the average value of three repeated measurements. The OCT images were obtained with dilated pupils. The estimated refractive error associated with the change in IOL depth was calculated using OpticStudio 16.5 Sp5 (Zemax, LLC.) [15, 16]. The calculations with OpticStudio were performed in the paraxial form. Therefore, the number of rays and aperture size did not contribute to the calculated results. Although asphericity affects the spherical results when comparing 4 days and 1 month spherical differences, to simplify the analysis, asphericity can be removed from the calculation of spherical differences. The eye model was built from the patients’ biometry data including the cornea power, aqueous depth, and AL (refer to the S1 File).

Fig 2

IOL depth measured using anterior-segment optical coherence tomography.

IOL, intraocular lens, Post-ACD; postoperative anterior chamber depth.

Manifest refractive spherical equivalent value (MRSE) determined as the spherical power plus half the cylindrical power and AS-OCT were measured postoperatively at 4 days and 1 month. All examinations, including a CDVA measurement using a Landolt C chart at 5 meters, were performed by experienced ophthalmic technicians unaware of the purpose of the study.

Statistical analyses were performed with JMP Pro version 14.3.0 (SAS Institute Inc.). Normality of data distribution was assessed using the Shapiro-Wilk normality test. Differences between IOL groups in IOL depth and other continuous variables with normal distribution were compared with an unpaired t-test. Continuous variables without normal distribution were compared using the Mann-Whitney U test. The data between each time-interval pair were compared using the paired t-test or Wilcoxon signed-rank test. The Pearson correlation coefficient was used to determine the strength of the linear association between the changes of MRSE and the changes in IOL depth and corneal power. The sample size was calculated to detect a difference in error of 0.1 mm between 2 groups; with a significance level of 5%, a statistical power of 80%, and assuming standard deviation (SD) to 0.11 mm, 41 eyes were required. Differences with a p-value less than 0.05 were considered statistically significant.

Results

The IOL with hinges was implanted in 42 eyes of 42 patients, and IOL without hinges was implanted in 42 eyes of 42 patients. Table 1 summarizes the demographic data and ocular dimensions of the two IOL groups. The mean age, ratio of men to women, preoperative AL, CCT, ACD, LT, K, and implanted IOL power did not significantly differ between the groups.

Table 1

Demographic data and preoperative optical properties of the eyes.

Characteristic	IOL with hinges groupn = 42		IOL without hinges groupn = 42		P Value
	Mean + SD	Range	Mean + SD	Range
Age (years)	73.8 ± 8.1	56 to 85	72.9 ± 7.8	56 to 87	0.57
Male/Female	14/28	---	16/26	---	0.65
Axial length (mm)	24.24 ± 1.64	21.68 to 28.58	23.90 ± 1.27	22.22 to 28.19	0.26
Ksteep (D)	44.92 ± 1.66	41.21 to 49.71	44.29 ± 1.31	40.61 to 47.14	0.06
Kflat (D)	43.69 ± 1.61	40.37 to 48.01	43.64 ± 1.30	40.27 to 46.68	0.89
Corneal thickness (mm)	525 ± 29	454 to 583	528 ± 29	467 to 594	0.67
ACD (mm)	3.17 ± 0.35	2.25 to 3.75	3.16 ± 0.32	2.46 to 4.01	0.60
Lens thickness (mm)	4.55 ± 0.41	3.60 to 5.26	4.54 ± 0.33	3.96 to 5.41	0.91
IOL (D)	20.1 ± 4.2	10 to 26	21.4 ± 3.0	13 to 26.5	0.12

ACD; anterior chamber depth, D; diopter, IOL; intraocular lens, K; corneal power, SD; standard deviation.

Mean postoperative IOL depth and ACD over time is shown in Table 2. Compared with the IOL without hinges group, the IOL with hinges group had significantly less change in IOL depth and ACD from 4 days to 1 month (p = 0.0002 and p = 0.0004, respectively; Fig 3). Accordingly, the IOL with hinges group had significantly less absolute axial movement from 4 days to 1 month compared with the IOL without hinges group (p = 0.0004). While corneal thickness and postoperative ACD obtained by swept-source AS-OCT were significantly reduced from 4 days to 1 month in both group, there was no significant difference in the change in corneal thickness between the two groups. Although posterior corneal power was statistically significant different from 4 days to 1 month after surgery in both groups, postoperative total and anterior corneal powers of each group did not show significant changes (Table 3). The IOL without hinges group had a significant myopic shift in MRSE compared with the IOL with hinges group (p = 0.03, Table 4).

Table 2

Comparison of mean (± SD) corneal thickness, postoperative anterior chamber depth, and intraocular lens depth, change in each parameter and absolute axial movement.

Parameters	IOL with hinges groupn = 42		IOL without hinges groupn = 42		P Valuea
Corneal thickness (um)	Mean ± SD	Range	Mean ± SD	Range
4 days postop.	562 ± 38	482 to 644	566 ± 30	510 to 647	0.59
1 month postop.	544 ± 32	471 to 615	545 ± 31	486 to 636	0.91
P Valueb	< .0001***		< .0001***
Postoperative ACD (mm)
4 days postop.	4.74 ± 0.27	4.30 to 5.29	4.75 ± 0.27	4.32 to 5.75	0.89
1 month postop.	4.70 ± 0.25	4.10 to 5.24	4.62 ± 0.25	4.21 to 5.53	0.15
P Valueb	0.002**		< .0001***
IOL depth (mm)
4 days postop.	4.19 ± 0.27	3.72 to 4.76	4.19 ± 0.28	3.73 to 5.24	0.95
1 month postop.	4.17 ± 0.25	3.56 to 4.77	4.08 ± 0.26	3.63 to 5.04	0.1
P Valueb	0.13		< .0001***
Change in corneal thickness (um)	17.8 ± 17.2	-11 to 75	21.1 ± 12.2	-2 to 51	0.31
Change in postoperative ACD (mm)	0.05 ± 0.09	-0.11 to 0.24	0.13 ± 0.12	-0.07 to 0.42	0.0004***
Change in IOL depth (mm)	0.02 ± 0.09	-0.13 to 0.23	0.11 ± 0.12	-0.10 to 0.40	0.0002***
Refractive change associated with change in IOL depth (D)c	0.02 ± 0.11	-0.19 to 0.39	0.15 ± 0.16	-0.15 to 0.55	0.0001***
Absolute axial movement (mm)	0.07 ± 0.06	0 to 0.23	0.13 ± 0.09	0.02 to 0.40	0.0004***

ACD = anterior chamber depth; IOL = intraocular lens; *Statistically significant difference, P < 0.05; P Valuea between the 2 IOL groups; P Valueb between the intervals; C calculated by the OpticStudio software.

Fig 3

Mean (± standard deviation) change in IOL depth between 4 days and 1 month after cataract surgery.

IOL, intraocular lens; W/O, without; Student t-test, ***p < 0.001.

Table 3

Comparison of mean (± SD) anterior and posterior corneal power, change in each corneal power.

Parameters	IOL with hinges groupn = 42	IOL without hinges groupn = 42	P Valuea
Anterior corneal power (D)
4 days postop.	49.39 ± 1.69	48.84 ± 1.44	0.18
1 month postop.	49.32 ± 1.70	48.86 ± 1.42	0.18
P Valueb	0.67	0.48
Posterior corneal power (D)
4 days postop.	-6.40 ± 0.30	-6.30 ± 0.27	0.10
1 month postop.	-6.34 ± 0.26	-6.24 ± 0.23	0.10
P Valueb	0.0003***	0.0015**
Corneal real power (D)
4 days postop.	43.04 ± 1.49	42.69 ± 1.27	0.25
1 month postop.	43.11 ± 1.50	42.74 ± 1.25	0.23
P Valueb	0.06	0.08
Change in anterior corneal power (D)	-0.02 ± 0.23	-0.02 ± 0.20	0.89
Change in posterior corneal power (D)	-0.07 ± 0.11	-0.05 ± 0.10	0.55
Change in corneal real power (D)	-0.07 ± 0.23	-0.06 ± 0.21	0.79

*Statistically significant difference; P Valuea between the 2 IOL groups; P Valueb between the intervals.

Table 4

Comparison of mean (± SD) change in manifest refractive spherical equivalent.

Parameters	IOL with hinges groupn = 42	IOL without hinges groupn = 42	P Valuea
4 days postop.	-1.08 ± 0.84	-0.75 ± 0.83	0.08
1 month postop.	-1.19 ± 0.78	-1.03 ± 0.79	0.34
P Valueb	0.03*	< .0001***
Change in MRSE (D)	0.11 ± 0.31	0.27 ± 0.36	0.03*

MRSE = manifest refractive spherical equivalent;

*Statistically significant difference;

P Valuea between the 2 IOL groups; P Valueb between the intervals.

To investigate the effect of the change in IOL depth on postoperative refraction, a general linear model analysis was performed for each group (Fig 4). The refractive change related to IOL shift from 4 days to 1 month in the IOL without hinges group was significantly correlated with the change in MRSE from 4 days to 1 month (r = 0.62, 95% confidence interval [CI] of 0.39 to 0.78; p < 0.0001); whereas there was no significant correlation in the IOL with hinges group (r = 0.22, 95% CI of -0.09 to 0.49; p = 0.15).

Fig 4

Correlations with the changes in refraction and IOL depth between 4 days and 1 month after cataract surgery: (a) IOL with hinges and (b) IOL without hinges.

The change in corneal power was not significantly correlated with the change in MRSE in both the IOL with hinges (r = 0.24, 95% CI of -0.07 to 0.50; p = 0.13) and IOL without hinges groups (r = 0.05, 95% CI of -0.26 to 0.35; p = 0.77).

Discussion

The present study demonstrates that the mean postoperative IOL depth of the IOL with hinges group was stable during the first month from postoperative day 4, while the mean postoperative IOL depth of the IOL without hinges group significantly decreased during the same period. The change in postoperative IOL depth between day 4 and 1 month was significantly correlated with the change in MRSE in the IOL without hinges group.

According to a previous report, the postoperative IOL depth significantly decreased between day 1 and 1 month in eyes with an AcrySof SN60WF IOL, which has the same haptic design as Acrysof IQ Toric IOLs, AMO ZCB00V IOLs, and Hoya XY-1 IOLs [9]. Recently, Clareon CNA0T0 IOL(Alcon), which also has the same haptics design as the AcrySof IQ Toric IOL, was reported to have a significant anterior shift of postoperative IOL depth between day 1 and 1 month [10]. In the present study, we set the IOL depth at postoperative day 4 as the reference and compared that value with the IOL depth at 1 month postoperative. Additionally, AL was positively correlated with the change in IOL depth from 4 days to 1 month in only the IOL without hinges group (S1 Fig). As a consequence, the IOL depth of IOL with hinges was stable from postoperative day 4 to postoperative 1 month. Considering that the haptics of the AcrySof IQ Toric IOL have a specific flexible hinge design in which the axial stiffness is greater than the lateral stiffness [13] and the haptics of the Vivinex iSert XY-1 IOL are straight (Fig 1), the presence or absence of the hinge may cause differences in postoperative anterior shift of the IOL even if IOLs are designed with planar haptics.

Based on OpticStudio software, a 20 D IOL with a 24 mm AL, 7.7 mm anterior corneal radii of curvature, and 6.8 mm posterior corneal radii of curvature would have axial forward movement of 0.1 mm, 0.2 mm, and 0.3 mm corresponding to a myopic shift in refraction of 0.13 D, 0.27 D, and 0.40 D, respectively [16]. The mean axial movement was less than 0.2 mm for both the IOL with hinges and IOL without hinges groups, which indicates a myopic shift of approximately 0.27 D based on modeling. Calculating the refractive change caused by the IOL shift in each subject demonstrates that the IOL shift strongly correlates with the changes in MRSE.

Klijn et al. evaluated the role of IOL position shift on long-term refractive shift from 1 month to 1 year after cataract surgery with implantation of Acrysof SA60AT IOL(Alcon) [17]. There was no correlation between the long-term change in refraction and the IOL position shift after cataract surgery, and Klijn et al. hypothesized that the postoperative refractive shift might be explained by natural fluctuations in corneal curvature [17]. In contrast, the current results reveal a correlation between the short-term change in refraction and the IOL position shift from 4 days and 1 month after cataract surgery in the IOL without hinges group, but no correlation in the IOL with hinges group. Moreover, there was no significant correlation in corneal curvature with the short-term change in refraction of both groups. This suggests that there must be other factors that better explain short-term refractive changes after cataract surgery or multiple factors might be intricately interrelated.

In the current study, the changes in posterior corneal curvature were statistically significant but clinically insignificant (-0.07 ± 0.11 [IOL with hinges] and -0.05 ± 0.10 [IOL without hinges], Table 3), although posterior corneal curvature significantly flattened from day 4 to 1 month in both groups after surgery. This result is consistent with previous reports. Jin et al. reported that postoperative focal flattening in the posterior cornea were detected in the early postoperative period [18]. Although the change in postoperative corneal power is one of the factor related to the postoperative change in MRSE, there was no correlation between the myopic shift of MRSE and the change in corneal power during the early postoperative period in the present study. Hence, the discrepancy between the refractive shift and corneal power change might be due other variables such as postoperative IOL shift. The postoperative stability of IOL position is one important factor for maintaining refractive stability.

This study has some limitations. First, postoperative ALs were not measured. Given the results of previous studies [9, 17, 19], it is unlikely that postoperative changes in AL are responsible for the changes in refraction. Second, two different IOL types were evaluated; namely, one was a mono-focal IOL and another was a toric mono-focal IOL. Future studies should be done with the same type of IOL. Third, the repeatability and reproducibility of AS-OCT measurements were not evaluated; however, this has been well proven in previous reports [20-22]. Future studies can also evaluate the effect of the change in IOL position and corneal value on the refractive prediction error of the IOL power calculation formula in a long-term study. Additionally, since subjective refraction is measured in 0.25 D steps, the results might vary with the examiner and patient. To compare postoperative changes in refraction, the use of 0.125 D steps for subjective refraction or an autorefractometer, which can measure values every 0.01 D, are options that can be used in the future [9].

In conclusion, despite similarities in material and planar haptics, postoperative IOL depth and axial movement can vary between two types of acrylic single-piece, open loop, foldable IOLs with different hinge designs at the early postoperative period (4 days to 1 month).

Correlations between axial length and the changes in IOL depth between 4 days and 1 month after cataract surgery: (a) IOL with hinges and (b) IOL without hinges.

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6 Apr 2022

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Reviewer #1: 1. How did you assess you case number?

2. Was the CASIA measurement performed only once in each case?

3. Was it performed by one examiner? Or more?

Could you please provide ZEMAX simulation results or table as supplementary material?

Reviewer #2: Comparison of two one-piece acrylic foldable intraocular lenses: Short-term change in

axial movement after cataract surgery and its effect on refraction

The study describes axial IOL movement of two different IOLs from day 4 to 1 month postoperatively and correlates it with changes in the MRSE over time.

Methods:

When the study was retrospectively conducted, it is unlikely that it took 15 months. Rather patients which had surgery in this timespan were included.

Can you explain in short how the ZEMAX software works?

Did you use the post-OP Cataract module of the Casia 2 software?

Why did the authors include 42 eyes when only 34 were required according to their sample size calculation? Due to the retrospective nature of the study, no drop out correction is necessary.

Why did the authors assume 0.1mm as a SD? There are a lot of studies available with SD`s for axial movement of IOLs.

Since you study axial movement of the eye, you should clearly state which viscoelastics were used during the conduct of the study. Did the surgeon also remove the OVD from behind the lens? I ask this because one of the IOLs was a toric IOL, usually a surgeon removes the OVD behind the lens very thoroughly to avoid postoperative IOL rotation due to remaining viscoelastic.

Did the surgeon remove viscoelastics for both groups under the same manner? Or were the same viscoealstics used? This could affect postoperative axial stabilization within the first weeks.

How was the postoperative refraction (MRSE) assessed at 4 days and 1 month? Objective or subjective refraction?

I miss a detailed description of both IOLs in the methods section (overall diameter, optic diameter, capsular bag angle, haptic resilience, and other characteristics)

Results:

It’s a little bit confusing that you present change in IOL depth and actual axial movement. What`s the difference between these two variables? You should describe this in detail in the methods.

Are the results absolute values? Since the IOL can move forward and backwards? This is a very essential point

I would also report the range for the IOL depths and/or IOL axial movements [min;max] or seeing Boxplots of the results to get a better feeling were all the results are located.

Discussion:

What do the authors mean by “constricted” and “straight” haptics, what exactly is the difference between the haptics of these two IOLs? A figure would be good for better understandability.

The overall discussion is well written.

I miss a single point: Since both of the IOLs show pretty much the same design, what may be the main reason or multiple reasons for this difference between the IOLs in axial movement?

Another important point: was IOL movement correlated with axial length? It has been shown in earlier studies, that shorter eyes (or shorter preoperative ACDs) are more prone to axial IOL movement postoperatively. (Schartmüller et al, JRS 2021) (Schartmüller et al ESCRS 2019 Paris)

Reviewer #3: The authors present an interesting manuscript about two different IOL (haptic) designs and their axial stability in the postoperative course. Results are set in context with refractive changes. Interestingly, the authors chose a toric lens and a nontoric lens, which leads to differences in the centration of the haptics, still I like the study design.

While I think that overall, the manuscript is very well composed, I do see a few open questions:

With Aquaeous depth as main criterion, the authors reported significant changes in posterior radial curvature but failed to report changes in CCT and in ACD. Changes in posterior corneal curvature might be a sign of swelling of the corneal endothelium, certain levels of Descemet striae and swelling are not seldom after cataract surgery. AQD should not be described without ACD and CCT.

What is lacking is a discussion about the ideal timeframe for lens constant optimization, as a shift of the IOL and refraction obviously influence constant optimization if refractive results for certain types of IOLs are analyzed too early.

I would think that an autorefractometer is influenced by the Abbe number of the IOL and a diffractive form. We see systematically differing results from subjective refraction that differ for various IOLs. I don’t necessarily advise to change to ARF. Furthermore, repeatability has proven better for us for subjective refraction than for pseudophakic objective refraction. It is of note that we actually have 0.125 Dpt steps for subjective refraction (although not for a phoropter) that can be used if 0.25 Dpt seems to be too imprecise.

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20 May 2022

All reviewers:

First of all, I would appreciate it if you could see the submitted response file. Just in case, the following is a transcription of the response without the figures.

Previously each IOL evaluated in this study was described by the product name. Based on the reviewers’ point, we are now referencing the products with descriptors “with hinges or without hinges” in lieu of product names to better clarify the argument of this manuscript.

Reviewer #1:

1. How did you assess you case number?

Response: We performed the sample size power calculation. At the end of the method section, we mentioned as follows; The sample size was calculated to detect a difference in error of 0.10 mm between 2 groups; with a significance level of 5%, a statistical power of 80%, and assuming standard deviation (SD) to 0.1 mm, 34 eyes were required. Page 7, line 132.

2. Was the CASIA measurement performed only once in each case?

Response: Thank you for this comment. The CASIA was performed three times in each visit and data is exported as the mean value of three measurements. We have added the explanation in the Methods section. Page6, line 111.

3. Was it performed by one examiner? Or more?

Response: Thank you for this comment. Yes, the CASIA was performed by one experienced ophthalmic technician. We have added clarification to the Methods section. Page 6, line 111.

4. Could you please provide ZEMAX simulation results or table as supplementary material?

Response: Thank you for this comment. In Table 2, we have already described the simulation results of refraction change associated with change in IOL position, those were estimated using OpticStudio 16.5 Sp5 (Zemax, LLC.), the industry standard optical system design software; however, the representation of the parameter was not clear. Therefore, we have changed “Estimated refractive error associated with change in IOL depth” to “Refractive change associated with change in IOL depth” and have added the phrase of “C calculated by the OpticStudio software” in the footnote of Table 2.

Reviewer #2:

Methods: When the study was retrospectively conducted, it is unlikely that it took 15 months. Rather patients which had surgery in this timespan were included.

Response: Thank you for this comment. As the reviewer pointed out, this was a retrospective, observational, comparative, single-center study of all patients who had undergone uncomplicated cataract surgery at the National Hospital Organization, Tokyo Medical Center, Tokyo, Japan, between December 2015 and February 2017. We corrected the sentence at the beginning of the Methods section. Page 5, line 74.

Can you explain in short how the ZEMAX software works?

Response: The Zemax software, the official name is "OpticStudio" [Zemax, LLC.], is the premier optical design software used by engineers around the globe for 30 years. We have corrected the name of the software in the manuscript. We can estimate the theoretical postoperative refractive change that is caused by postoperative axial movement of IOL by using the OpticStudio software (see the attached screenshot of OpticStudio software). For example, if one eye showed 0.2 mm forward shift of IOL between postoperative 4 days and 1 month, the refractive changes caused by the change in IOL position are affected by the IOL power, corneal power, and axial length. Eventually, we can calculate the estimated refractive change associated with change in IOL depth. The results of these simulations using the OpticStudio was shown in Table 2 as “Refractive change associated with change in IOL depth (D)c.” “C” is explained in the footnote of Table 2.

Did you use the post-OP Cataract module of the Casia 2 software?

Response: Yes, we used the post-op cataract module of the Casia2, which gave us the postoperative aqueous depth, corneal thickness, and anterior chamber depth as well.

Why did the authors include 42 eyes when only 34 were required according to their sample size calculation? Due to the retrospective nature of the study, no drop out correction is necessary.

Response: Thank you for this comment. Before the current study started, we had a data set of 42 eyes for each group. When we proposed this study, we performed a sample size calculation to confirm whether the subject number was enough for the investigation of the topic.

In this revision, we have randomly selected 34 eyes from 42 eyes, and analyzed the data. We have validated this analysis three times. As the result, every data set demonstrated significant difference shown in the table below.

Comparison of IOL depth between IQ Toric and XY-1

n = 34 IQ Toric XY-1 P value

1st 0.014 ± 0.076 0.098 ± 0.127 0.0015

2nd 0.023 ± 0.090 0.096 ± 0.126 0.0077

3rd 0.029 ± 0.018 0.129 ± 0.018 0.0002

34 eyes were randomly selected from 42 eyes

In addition, as we mentioned the detail in the next question below, once we use the SD of 0.11, the power calculation tells us that 41 subjects are needed. Based on these calculation result, the data set of 42 subjects seems to be appropriate for this investigation.

Why did the authors assume 0.1mm as a SD? There are a lot of studies available with SD`s for axial movement of IOLs.

Response: Thank you for this constructive comment. To determine the SD of the change in IOL position to perform the power calculation, we referred to the article published by Hayashi K, et al. (doi:10.1016/j.ajo.2020.05.031.). Given that the SD of the change in IOL position in the paper was 0.11mm, we should have use 0.11 mm for SD. If we performed sample size power analysis to detect a difference in error of 0.1 mm between two groups; with a significance level of 5%, a statistical power of 80%, and assuming standard deviation (SD) to 0.11 mm, 41 eyes were required. Based on these data, we concluded that 42 subjects are appropriate to investigate the postoperative change in IOL depth. We have edited the sentence related to power sample analysis at the end of the Methods section. Page 6, line 132.

Since you study axial movement of the eye, you should clearly state which viscoelastics were used during the conduct of the study. Did the surgeon also remove the OVD from behind the lens? I ask this because one of the IOLs was a toric IOL, usually a surgeon removes the OVD behind the lens very thoroughly to avoid postoperative IOL rotation due to remaining viscoelastic.

Did the surgeon remove viscoelastics for both groups under the same manner? Or were the same viscoealstics used? This could affect postoperative axial stabilization within the first weeks.

Response: Thank you for this insightful comment. I have added the information of OVD. Additionally, the surgeon removed the same OVD with the same manner for both groups. Briefly, the I/A tip is inserted behind the IOL optic and the posterior chamber is directly irrigated and cleaned. I have added the explanations of these procedures in the Methods section. Page 5, line 94.

How was the postoperative refraction (MRSE) assessed at 4 days and 1 month? Objective or subjective refraction?

Response: Thank you for this comment. Subjective MRSE was assessed at 4 days and 1 month.

I miss a detailed description of both IOLs in the methods section (overall diameter, optic diameter, capsular bag angle, haptic resilience, and other characteristics)

Response: Thank you for this comment. We have added the information of both IOLs in the Methods section of the manuscript with the photograph of both IOLs. Both of the IOLs made of acrylic material have 13.0 mm overall diameter, 6.0 mm optic diameter, and planar-haptic design, whereas IQ Toric IOL has a specific flexible hinge design. We have added the information of each IOL in the Methods section (page 5, line 92). There is no available information of haptic resilience.

Results:

It’s a little bit confusing that you present change in IOL depth and actual axial movement. What`s the difference between these two variables? You should describe this in detail in the methods. Are the results absolute values? Since the IOL can move forward and backwards? This is a very essential point.

Response: Thank you for this constructive comment. Whereas the change in IOL depth is the numerical value, the actual axial movement is the absolute value. As the reviewer pointed out the definitions of these parameters are a little confusing, we have replaced “actual axial movement” with “absolute axial movement” in Table 2.

I would also report the range for the IOL depths and/or IOL axial movements [min;max] or seeing Boxplots of the results to get a better feeling were all the results are located.

Response: Thank you for this constructive comment. I have added the data of [min:max] in Table 2 and have made the graph including all dots as Figure 3 (see below).

Fig 3. Fig 3. Mean (± standard deviation) change in IOL depth between 4 days and 1 month after cataract surgery. IOL, intraocular lens; W/O, without; Student t-test, ***p < 0.001

Discussion:

What do the authors mean by “constricted” and “straight” haptics, what exactly is the difference between the haptics of these two IOLs? A figure would be good for better understandability.

Response: We appreciate this valuable comment. We have added the photographs of IOLs as Fig 1 that emphasizes the difference of the haptics structure.

Fig 1. Optic and haptic configurations of (a) IOL with hinges and (b) IOL without hinges. While both of IOLs have planar haptics designs with a 0-degree angle, the haptics of the IOL with hinges (c) are constricted (i.e. flexible hinge design, black arrows) and the haptics of the IOL without hinges (d) are straight.

The overall discussion is well written. I miss a single point: Since both of the IOLs show pretty much the same design, what may be the main reason or multiple reasons for this difference between the IOLs in axial movement?

Response: Thank you for this constructive comment. Both of IOLs have planar-haptic design, whereas IQ Toric IOL has a specific flexible hinge design (Fig 1. C, black arrows). Based on an in vitro experiment (IOL compression test), the planar haptics with a flexible hinge design could minimize axial forces and allow the IOLs to remain planar when compressed. 13 Although the axial stability of IOLs has been proved in vitro, there was less clinical data. We believe that the difference in haptic configurations would be the main factor that provides the postoperative stability.

13. Lane S, Collins S, Das KK, et al. Evaluation of intraocular lens mechanical stability. J Cataract Refract Surg 2019;45:501–506.

Another important point: was IOL movement correlated with axial length? It has been shown in earlier studies, that shorter eyes (or shorter preoperative ACDs) are more prone to axial IOL movement postoperatively. (Schartmüller et al, JRS 2021) (Schartmüller et al ESCRS 2019 Paris)

Response: Thank you for this constructive comment. We have confirmed the relationship between axial length and axial IOL movement, indicating that longer eyes are more prone to axial IOL movement postoperatively in only XY-1 (IOL without hinges) group, which is the opposite result of Schartmüller et al, JRS 2021. There are several differences between our study and Schartmüller et al, such as the observation period and the type of IOL. We assumed that longer eye tends to have larger bag, and as such IOLs can more easily to move in the bag postoperatively. At least, the result shown as S1 Fig might also indicate that IQ Toric IOLs (IOL with hinges) are more stable. We have added this result to the Discussion section and added supplemental figure 1. Page12, line 194.

S1 Fig. Correlations between axial length and the changes in IOL depth between 4 days and 1 month after cataract surgery: (a) IOL with hinges and (b) IOL without hinges.

Reviewer #3:

The authors present an interesting manuscript about two different IOL (haptic) designs and their axial stability in the postoperative course. Results are set in context with refractive changes. Interestingly, the authors chose a toric lens and a nontoric lens, which leads to differences in the centration of the haptics, still I like the study design.

While I think that overall, the manuscript is very well composed, I do see a few open questions: With Aqueous depth as main criterion, the authors reported significant changes in posterior radial curvature but failed to report changes in CCT and in ACD. Changes in posterior corneal curvature might be a sign of swelling of the corneal endothelium, certain levels of Descemet striae and swelling are not seldom after cataract surgery. AQD should not be described without ACD and CCT.

Response: Thank you for providing this insightful comment. As the reviewer recommended, we have analyzed the changes in CCT and ACD. Whereas there was no significant difference in change in CCT between 2 groups (p = 0.31), the change in ACD was significantly smaller in IQ Toric (IOL with hinges) group than XY-1 (IOL without hinges) group, which is the same as the result of IOL depth (i.e. postoperative AQD). We have added these results in Table 2. Subsequently, the change in ACD was significantly correlated with the refractive changes in XY-1 group (r = 0.63, p < 0.0001), but there was no significant difference in IQ Toric group (r = 0.21, p = 0.20); this result is also the same as the change in AQD.

What is lacking is a discussion about the ideal timeframe for lens constant optimization, as a shift of the IOL and refraction obviously influence constant optimization if refractive results for certain types of IOLs are analyzed too early.

Response: Thank you for this valuable comment. We agree with the reviewer’s comment. Therefore, we have added the following discussion in the Discussion section: The postoperative stability of IOL position is one important factor for maintaining refractive stability. Page 13, line 230.

The purpose of the current study is to investigate the postoperative IOL axial movement, not improve the prediction error of the IOL power calculation formulas. Even though there are a lot of IOL formulas, we can say that at least 1 month or more after surgery is required to evaluate the postoperative refraction as many studies reported.

I would think that an autorefractometer is influenced by the Abbe number of the IOL and a diffractive form. We see systematically differing results from subjective refraction that differ for various IOLs. I don’t necessarily advise to change to ARF. Furthermore, repeatability has proven better for us for subjective refraction than for pseudophakic objective refraction. It is of note that we actually have 0.125 Dpt steps for subjective refraction (although not for a phoropter) that can be used if 0.25 Dpt seems to be too imprecise.

Response: We truly appreciate your comments. As you recommended, we would like to have 0.125 D steps for subjective refraction, which would give us more promising results in this field. I have added this recommendation in the Discussion section. Page14, line 241.

Submitted filename: PONE-D-22-01418 Response to Reviewers.docx

Click here for additional data file.

7 Jul 2022

1 Aug 2022

Manuscript ID: PONE-D-22-01418

Title: Comparison of two one-piece acrylic foldable intraocular lenses: Short-term change in axial movement after cataract surgery and its effect on refraction

Point-by-Point Response 2

Reviewer #1:

The authors have properly addressed all comments. The manuscript is now improved in all its part. I suggest to send the exact ZEMAX table as Supplementary materials.

Response: Thank you for this constructive comment. At the reviewer’s suggestion, we have added supporting information, which includes an exact ZEMAX table based on the “zmx” file and screenshots of the Lens Data Editor and Effective Focal Length (EFL) and axial Longitudinal Spherical Aberration (LSA0). Page 6, line 121.

Supporting Information

Method:

Zemax OpticStudio (ZOS) was used to evaluate the refractive errors from the change in postoperative lens position (the difference between 4 days postop and 1 month postop).

All ocular biometric parameters were obtained from preoperative measurement data and assumed to be constant in order to not interfere with the lens position variability.

The procedures were as follows:

1. Cornea anterior radius curvature was calculated by 337.5/PreOp(AveK).

2. Cornea posterior radius curvature was assumed to be constant for all subjects, and defined as 6.5 mm.

3. Cornea center thickness was assumed to be constant for all subjects, and defined as 550 mm.

4. Cornea and aqueous refractive indices were defined as 1.376 and 1.336, respectively.

5. IOL design and refractive indices were given by the manufacturers.

6. Axial power was obtained by PreOp(AL).

7. Lens positions were determined using the measurement results at 4 days and 1 month.

8. Back focal length (the distance from the posterior IOL to the retina) was then calculated using the aforementioned distances.

All the information was inputted into the ZOS Lens Data Editor, and ZOS calculated the Effective Focal Length (EFL) and axial Longitudinal Spherical Aberration (LSA0) (Supplemental figure).

The refractive error was calculated using the following formula

SE = -(1000/EFL – 1000/(EFL-LSA0))

Raw data of ZOSModel.zmx:

MODE SEQ

NAME

PFIL 0 0 0

LANG 0

UNIT MM X W X CM MR CPMM

FLOA

ENVD 35 1 1

GFAC 0 0

GCAT SCHOTT

RAIM 0 2 1 1 0 0 0 0 0 1

PUSH -2.7131892210931558e-05 0 0 0 0 0

SDMA 0 1 0

OMMA 1 1

FTYP 0 0 1 1 0 0 0

ROPD 2

HYPR 0

PICB 1

XFLN 0 0 0 0 0 0 0 0 0 0 0 0

YFLN 0 0 0 0 0 0 0 0 0 0 0 0

FWGN 1 1 1 1 1 1 1 1 1 1 1 1

VDXN 0 0 0 0 0 0 0 0 0 0 0 0

VDYN 0 0 0 0 0 0 0 0 0 0 0 0

VCXN 0 0 0 0 0 0 0 0 0 0 0 0

VCYN 0 0 0 0 0 0 0 0 0 0 0 0

VANN 0 0 0 0 0 0 0 0 0 0 0 0

WAVM 1 0.54607399999999995 1

WAVM 2 0.55000000000000004 1

WAVM 3 0.55000000000000004 1

WAVM 4 0.55000000000000004 1

WAVM 5 0.55000000000000004 1

WAVM 6 0.55000000000000004 1

WAVM 7 0.55000000000000004 1

WAVM 8 0.55000000000000004 1

WAVM 9 0.55000000000000004 1

WAVM 10 0.55000000000000004 1

WAVM 11 0.55000000000000004 1

WAVM 12 0.55000000000000004 1

WAVM 13 0.55000000000000004 1

WAVM 14 0.55000000000000004 1

WAVM 15 0.55000000000000004 1

WAVM 16 0.55000000000000004 1

WAVM 17 0.55000000000000004 1

WAVM 18 0.55000000000000004 1

WAVM 19 0.55000000000000004 1

WAVM 20 0.55000000000000004 1

WAVM 21 0.55000000000000004 1

WAVM 22 0.55000000000000004 1

WAVM 23 0.55000000000000004 1

WAVM 24 0.55000000000000004 1

PWAV 1

POLS 1 0 1 0 0 1 0

GLRS 3 0

GSTD 0 100.000 100.000 100.000 100.000 100.000 100.000 0 1 1 0 0 1 1 1 1 1 1

NSCD 100 500 0 0.001 5 9.9999999999999995e-07 0 0 0 0 0 0 1000000 0 2

COFN QF "COATING.DAT" "SCATTER_PROFILE.DAT" "ABG_DATA.DAT" "PROFILE.GRD"

COFN COATING.DAT SCATTER_PROFILE.DAT ABG_DATA.DAT PROFILE.GRD

SURF 0

COMM Object Distance

TYPE STANDARD

FIMP

CURV 0.0 0 0 0 0 ""

HIDE 0 0 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 9

DISZ INFINITY

DIAM 0 0 0 0 1 ""

MEMA 0 0 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

SURF 1

COMM Cornea Anterior

TYPE STANDARD

FIMP

CURV 1.386962962962962342E-01 0 0 0 0 ""

HIDE 0 0 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 1

DISZ 0.55000000000000004

GLAS ___BLANK 1 0 1.3759999999999999 0 0 0 0 0 0 0

DIAM 5 1 0 0 1 ""

MEMA 5 0 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 5 0

SURF 2

COMM Cornea Posterior

TYPE STANDARD

FIMP

CURV 1.538461538461538547E-01 0 0 0 0 ""

HIDE 0 1 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 2

DISZ 3.8639999999999999

GLAS ___BLANK 1 0 1.3360000000000001 0 0 0 0 0 0 0

DIAM 5 1 0 0 1 ""

MEMA 5 0 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 5 0

SURF 3

COMM Pupil

STOP

TYPE STANDARD

FIMP

CURV 0.0 0 0 0 0 ""

HIDE 0 1 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 3

DISZ 0

GLAS ___BLANK 2 2 1.3360000000000001 0 0 0 0 0 0 0

DIAM 1.5 1 0 0 1 ""

MEMA 1.5 1 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 1.5 0

SURF 4

COMM IOL Anterior

TYPE STANDARD

FIMP

CURV 5.263157894736841813E-02 0 0 0 0 ""

HIDE 0 0 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 4

DISZ 0.69999999999999996

GLAS ___BLANK 1 0 1.5 0 0 0 0 0 0 0

DIAM 3 1 0 0 1 ""

MEMA 3 1 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 3 0

SURF 5

COMM IOL Posterior

TYPE STANDARD

FIMP

CURV -5.263157894736841813E-02 0 0 0 0 ""

HIDE 0 1 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 5

DISZ 17.274000000000001

GLAS ___BLANK 2 2 1.3360000000000001 0 0 0 0 0 0 0

DIAM 3 1 0 0 1 ""

MEMA 3 1 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 3 0

SURF 6

TYPE STANDARD

FIMP

CURV 0.0 0 0 0 0 ""

HIDE 0 0 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 8

DISZ 0

DIAM 0.040796963281374721 0 0 0 1 ""

MEMA 5 0 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

EFFL 0 1 0 0 0 0 0 0 0 0

LONA 0 0 0 0 0 0 0 0 0 0

TOL TOFF 0 0 0 0 0 0 0 0

MNUM 1 1

MOFF 0 1 "" 0 0 0 1 1 0 0.0 "" 0

Reviewer #3:

I didn’t view this as critical in my first review, but as both other reviewers noticed this point I have to agree that the description of how OpticStudio was used is kind of lacking in this study. Apparently the authors used a simulation model with 7 rays? Which model eye was chosen? Did the authors use full aperture raytracing or the paraxial simplification form? Was the individual pupil size and asphericity considered? Considering 2 different IOL designs were used was IOL geometry data known? At least all the actual simulation details used for this analysis should be provided in the materials section.

Response:

Thank you for this constructive comment. As the reviewer pointed out, we have added the details related to how to analyze the data using ZEMAX software in the Method section as follows (page 6, line 115):

The calculations with OpticStudio were performed in the paraxial form. Therefore, the number of rays and aperture size did not contribute to the calculated results. Although asphericity affects the spherical results when comparing 4 days and 1 month spherical differences, to simplify the analysis, asphericity can be removed from the calculation of spherical differences. The eye model was built from the patients' biometry data including the cornea power, aqueous depth, and AL (refer to the Supporting Information).

Additionally, we have added the following “Supporting Information” file to describe the details of how to analyze the data with the OpticStudio.

Supporting Information

Method:

Zemax OpticStudio (ZOS) was used to evaluate the refractive errors from the change in postoperative lens position (the difference between 4 days postop and 1 month postop).

All ocular biometric parameters were obtained from preoperative measurement data and assumed to be constant in order to not interfere with the lens position variability.

The procedures were as follows:

9. Cornea anterior radius curvature was calculated by 337.5/PreOp(AveK).

10. Cornea posterior radius curvature was assumed to be constant for all subjects, and defined as 6.5 mm.

11. Cornea center thickness was assumed to be constant for all subjects, and defined as 550 mm.

12. Cornea and aqueous refractive indices were defined as 1.376 and 1.336, respectively.

13. IOL design and refractive indices were given by the manufacturers.

14. Axial power was obtained by PreOp(AL).

15. Lens positions were determined using the measurement results at 4 days and 1 month.

16. Back focal length (the distance from the posterior IOL to the retina) was then calculated using the aforementioned distances.

All the information was inputted into the ZOS Lens Data Editor, and ZOS calculated the Effective Focal Length (EFL) and axial Longitudinal Spherical Aberration (LSA0) (Supplemental figure).

The refractive error was calculated using the following formula

SE = -(1000/EFL – 1000/(EFL-LSA0))

Raw data of ZOSModel.zmx:

MODE SEQ

NAME

PFIL 0 0 0

LANG 0

UNIT MM X W X CM MR CPMM

FLOA

ENVD 35 1 1

GFAC 0 0

GCAT SCHOTT

RAIM 0 2 1 1 0 0 0 0 0 1

PUSH -2.7131892210931558e-05 0 0 0 0 0

SDMA 0 1 0

OMMA 1 1

FTYP 0 0 1 1 0 0 0

ROPD 2

HYPR 0

PICB 1

XFLN 0 0 0 0 0 0 0 0 0 0 0 0

YFLN 0 0 0 0 0 0 0 0 0 0 0 0

FWGN 1 1 1 1 1 1 1 1 1 1 1 1

VDXN 0 0 0 0 0 0 0 0 0 0 0 0

VDYN 0 0 0 0 0 0 0 0 0 0 0 0

VCXN 0 0 0 0 0 0 0 0 0 0 0 0

VCYN 0 0 0 0 0 0 0 0 0 0 0 0

VANN 0 0 0 0 0 0 0 0 0 0 0 0

WAVM 1 0.54607399999999995 1

WAVM 2 0.55000000000000004 1

WAVM 3 0.55000000000000004 1

WAVM 4 0.55000000000000004 1

WAVM 5 0.55000000000000004 1

WAVM 6 0.55000000000000004 1

WAVM 7 0.55000000000000004 1

WAVM 8 0.55000000000000004 1

WAVM 9 0.55000000000000004 1

WAVM 10 0.55000000000000004 1

WAVM 11 0.55000000000000004 1

WAVM 12 0.55000000000000004 1

WAVM 13 0.55000000000000004 1

WAVM 14 0.55000000000000004 1

WAVM 15 0.55000000000000004 1

WAVM 16 0.55000000000000004 1

WAVM 17 0.55000000000000004 1

WAVM 18 0.55000000000000004 1

WAVM 19 0.55000000000000004 1

WAVM 20 0.55000000000000004 1

WAVM 21 0.55000000000000004 1

WAVM 22 0.55000000000000004 1

WAVM 23 0.55000000000000004 1

WAVM 24 0.55000000000000004 1

PWAV 1

POLS 1 0 1 0 0 1 0

GLRS 3 0

GSTD 0 100.000 100.000 100.000 100.000 100.000 100.000 0 1 1 0 0 1 1 1 1 1 1

NSCD 100 500 0 0.001 5 9.9999999999999995e-07 0 0 0 0 0 0 1000000 0 2

COFN QF "COATING.DAT" "SCATTER_PROFILE.DAT" "ABG_DATA.DAT" "PROFILE.GRD"

COFN COATING.DAT SCATTER_PROFILE.DAT ABG_DATA.DAT PROFILE.GRD

SURF 0

COMM Object Distance

TYPE STANDARD

FIMP

CURV 0.0 0 0 0 0 ""

HIDE 0 0 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 9

DISZ INFINITY

DIAM 0 0 0 0 1 ""

MEMA 0 0 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

SURF 1

COMM Cornea Anterior

TYPE STANDARD

FIMP

CURV 1.386962962962962342E-01 0 0 0 0 ""

HIDE 0 0 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 1

DISZ 0.55000000000000004

GLAS ___BLANK 1 0 1.3759999999999999 0 0 0 0 0 0 0

DIAM 5 1 0 0 1 ""

MEMA 5 0 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 5 0

SURF 2

COMM Cornea Posterior

TYPE STANDARD

FIMP

CURV 1.538461538461538547E-01 0 0 0 0 ""

HIDE 0 1 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 2

DISZ 3.8639999999999999

GLAS ___BLANK 1 0 1.3360000000000001 0 0 0 0 0 0 0

DIAM 5 1 0 0 1 ""

MEMA 5 0 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 5 0

SURF 3

COMM Pupil

STOP

TYPE STANDARD

FIMP

CURV 0.0 0 0 0 0 ""

HIDE 0 1 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 3

DISZ 0

GLAS ___BLANK 2 2 1.3360000000000001 0 0 0 0 0 0 0

DIAM 1.5 1 0 0 1 ""

MEMA 1.5 1 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 1.5 0

SURF 4

COMM IOL Anterior

TYPE STANDARD

FIMP

CURV 5.263157894736841813E-02 0 0 0 0 ""

HIDE 0 0 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 4

DISZ 0.69999999999999996

GLAS ___BLANK 1 0 1.5 0 0 0 0 0 0 0

DIAM 3 1 0 0 1 ""

MEMA 3 1 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 3 0

SURF 5

COMM IOL Posterior

TYPE STANDARD

FIMP

CURV -5.263157894736841813E-02 0 0 0 0 ""

HIDE 0 1 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 5

DISZ 17.274000000000001

GLAS ___BLANK 2 2 1.3360000000000001 0 0 0 0 0 0 0

DIAM 3 1 0 0 1 ""

MEMA 3 1 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

FLAP 0 3 0

SURF 6

TYPE STANDARD

FIMP

CURV 0.0 0 0 0 0 ""

HIDE 0 0 0 0 0 0 0 0 0 0

MIRR 2 0

SLAB 8

DISZ 0

DIAM 0.040796963281374721 0 0 0 1 ""

MEMA 5 0 0 0 1 ""

POPS 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0

EFFL 0 1 0 0 0 0 0 0 0 0

LONA 0 0 0 0 0 0 0 0 0 0

TOL TOFF 0 0 0 0 0 0 0 0

MNUM 1 1

MOFF 0 1 "" 0 0 0 1 1 0 0.0 "" 0

Regarding the answer to my own comments on IOL constants optimization:

“The purpose of the current study is to investigate the postoperative IOL axial movement, not improve the prediction error of the IOL power calculation formulas.”

Well, why else are we interested in axial IOL movement, if not for right (right lens constant) and stable (good IOL design) refractive results?

Anyways, “we can say that at least 1 month or more after surgery is required to evaluate the postoperative refraction as many studies reported” is a sufficient statement, this doesn’t have to go into an in-depth analysis of every IOL calculation formula.

Response:

We appreciate this valuable comment, and totally agree with your comment.

I think the statement “the industry standard optical system design” sounds a bit like advertisement, can this be omitted?

Response:

Thank you for this comment. We have deleted the part in the manuscript as recommended.

I figure the refraction lane length was standardized? Which lane length was used?

Response:

Thank you for this comment. CDVA was measured at 5 meters. Therefore, we have added this information in the Method section. Page 7, line 124.

Submitted filename: @PONE-D-22-01418 Response to Reviewers2.docx

Click here for additional data file.

9 Aug 2022

Comparison of two one-piece acrylic foldable intraocular lenses: Short-term change in axial movement after cataract surgery and its effect on refraction

PONE-D-22-01418R2

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Reviewers' comments:

22 Aug 2022

PONE-D-22-01418R2

Comparison of two one-piece acrylic foldable intraocular lenses: Short-term change in axial movement after cataract surgery and its effect on refraction

Dear Dr. Maeda:

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