Evaluation of Resin Molds Change in Design and Polymerization by

Using a Wavefront Sensor

Kazumasa Tatsumi

1,2 a

, Kentaro Saeki

,Shin Kubota

, Yoshikatsu Kaneda

, Kenji Uno

1,3

Kazuhiko Ohnuma

1,3

and Tatsuo Shiina

SEED CO., LTD, 2-40-2 Hongo, Bunkyo-ku, Tokyo, 369-0131, Japan

Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba-shi, Chiba, 263-8522, Japan

Laboratorio de Lente Verde, 98-1 Nozomino, Sodegaura, Chiba, 299-0251, Japan

Keywords: Wavefront Sensor, Wavefront Shape, Contact Lenses, Resin, Mold.

Abstract: Advances in molding technology have made it possible to produce plastic molded products with complex

shapes. In contact lens manufacturing, a double-sided molding method using resin molds is employed, where

the front and back designs are replicated through injection molding. However, shape changes in the resin

molds caused by heat treatment (polymerization) during the manufacturing process affect lens characteristics.

This study proposes a method using optical techniques to clarify the influence of mold design and

polymerization on resin mold shapes. Five types of resin molds were measured using a wavefront sensor,

which allows for high-accuracy, non-contact measurement. Wavefront aberrations and radii of curvature were

evaluated, and results showed that polymerization caused slight deviations from the design values and changes

in shrinkage rates. This method demonstrated its effectiveness in measuring and evaluating resin molds for

contact lens production. Furthermore, the proposed method has wide-ranging applications, including quality

control in lens manufacturing and evaluating the transfer accuracy of metal molds.

1 INTRODUCTION

Injection molding technology, which has been rapidly

advancing in recent years, is one of the most

important technologies in the plastics industry. Since

John W. Hyatt invented the vertical celluloid molding

machine in 1872, laying the foundation for injection

molding, the technology has seen significant growth,

especially in the latter half of the 20th century

(Rosato, 2000). Innovations in both injection molding

techniques and plastic materials have greatly

enhanced production efficiency (Ciofu, 2013). The

introduction of automatic control systems using

microprocessors has made it possible to manufacture

parts with even greater complexity and precision.

Since the 1990s, injection molding has become more

refined and has evolved into a technology widely

used in fields such as medical devices and electronic

components.

https://orcid.org/0009-0008-2975-7695

https://orcid.org/0000-0002-4902-3110

https://orcid.org/0000-0001-9292-4523

Contact lenses are one of the medical devices

manufactured using injection molding technology. In

a world where myopia is increasing due to the

widespread use of smartphones and other tiny small

display devices, the global demand for contact lenses

is rising year by year. Consequently, there is a need

to mass-produce and high-quality contact lenses. The

concept of contact lenses was first introduced by

Leonardo da Vinci in 1508, and later in 1888, Adolf

Fick developed a glass scleral lens, marking the first

step toward their practical use (Oswald, 2008).

Similar to the advancements in injection molding, the

development of plastic materials also had a

significant impact on contact lenses, leading to the

creation of plastic scleral lenses, which greatly

reduced their weight and improved their durability

(Ciofu, 2013). In the 1960s, soft contact lenses made

from hydrogel materials, developed by Otto

Wichterle and Drahoslav Lim, were introduced and

remain popular today (Oswald, 2008).

Tatsumi, K., Saeki, K., Kubota, S., Kaneda, Y., Uno, K., Ohnuma, K. and Shiina, T.

Evaluation of Resin Molds Change in Design and Polymerization by Using a Wavefront Sensor.

DOI: 10.5220/0013150400003902

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 13th International Conference on Photonics, Optics and Laser Technology (PHOTOPTICS 2025), pages 20-27

ISBN: 978-989-758-736-8; ISSN: 2184-4364

Injection molding technology and contact lens

manufacturing are closely related. While glass lenses

are hand-polished, plastic soft contact lenses are

produced using a cast molding method that utilizes a

mold created through injection molding (Chen,

2017). A metal mold is made to replicate the front and

back designs, and a resin mold is then produced

through injection molding. The contact lenses are

formed by pouring the lens material into two resin

molds and fitting them together.

In the cast molding method, the surface of the

resin mold must be precisely and smoothly formed to

improve the quality of contact lenses (Chen, 2017).

Since the raw material for contact lenses is liquid, a

solid lens is formed through a heat treatment

(polymerization). Polymerization is carried out by

pouring the raw material into the resin mold and

sealing it. The space within the fitted resin mold

determines the shape of the contact lens, making the

precision of the mold surface crucial. Therefore, both

the mold design and the molding conditions during

manufacturing are key factors in producing high-

quality contact lenses, and research has been

conducted to optimize these conditions (Chen, 2017)

(Chang, 2001).

In mass production, resin molds are created under

nearly identical basic molding conditions, but

differences in precise design should still be evaluated.

Additionally, the influence of the polymerization on

the resin mold during the manufacturing process must

also be considered. This is because plastic, the

primary material for resin molds today, is more prone

to deform than glass or metal, and can change shape

when exposed to high temperature, around 100°C.

Resin molds are typically evaluated by using a

compact laser interferometer, but since the

measurements rely on the person interpreting the

interference fringes displayed during the

measurement, quantitative assessments are not

possible, and differences among them can arise.

In this study, we propose a method for evaluating

resin molds using a wavefront sensor to quantitatively

perform high-precision inspections. The wavefront

sensor allows for highly accurate wavefront

measurements at the sub-nanometer level using

Zernike polynomials. Additionally, it can acquire

aberration data within a few milliseconds, allowing

the detection of aberration changes real-time

(Atchison, 2005). Zernike coefficients can be

displayed as numerical parameters, providing

detailed measurements of the resin mold's

aberrations. Additionally, the radius of curvature can

be measured simultaneously, making the wavefront

sensor a promising alternative to interferometers.

Previous research has demonstrated that

measurements obtained from wavefront sensors

function effectively as evaluation indices for aspheric

lenses (Cheng, 2020). Given the high precision of the

measurement parameters, this study utilizes the

wavefront sensor to measure both the aberrations and

the radius of curvature of the resin molds. This study

aims to clarify how the design and polymerization

during the manufacturing process affect changes in

the aberration and radius of curvature of the resin

molds. It enables measurements with the same

accuracy as conventional measurement of

interferometer, while also providing real-time, stable

measurements. Therefore, it is innovative not only for

contact lens manufacturing but also for quality

control in medical devices and precision molded

products.

2 EXPERIMENTS

2.1 Experimental Equipment

Table 1 shows an overview of the wavefront sensor

used in this study. This device was specifically

designed to measure the reflected wavefront of resin

molds (Pulstec Industrial Co., Ltd.: LUCAS). Figure

1 illustrates the measurement principle. It employs

the Shack-Hartmann principle, using either a Charge

Coupled Device (CCD) or a Complementary Metal

Oxide Semiconductor (CMOS) as the imaging

element, which is composed of many microlenses

(Atchison, 2005). A laser is irradiated from the light

source, and the reflected light from the measurement

object passes through the microlenses and is directed

to the imaging element. As shown in Figure 2, if there

is no distortion in the wavefront of the measurement

object, equally spaced focused spots are formed on

the imaging surface according to the arrangement of

the microlenses. On the other hand, if the wavefront

is disturbed due to a phase change caused by the

measurement object, the incident direction of the light

beam changes due to the arrangement of each lens,

resulting in irregular Hartmann spot positions.

Information about the shape of the incident wavefront

can be obtained from this change in position. Its

information of the Hartmann spots is then expressed

using Zernike polynomials, which are orthogonal

polynomials defined on a unit circle. Each Zernike

polynomial represents an independent wavefront

shape, corresponding to a specific type of aberration

(Matsuyama, 2004).

Evaluation of Resin Molds Change in Design and Polymerization by Using a Wavefront Sensor

Using Zernike polynomials 𝑍

𝑛

𝑚

𝑋,𝑌 , the

incident equiphase surface is expressed as shown in

Equation (1).

𝑊



𝑋,𝑌



𝑐

𝑖

𝑗

1

𝑖

𝑗

0

𝑛

𝑖0

𝑍

𝑖

𝑗

1



𝑋,𝑌



(1)

𝑐

𝑖

2𝑗1

represents the coefficients corresponding to

each term of the Zernike polynomials. These

coefficients indicate the contribution of each term to

the wavefront aberration. The larger the value of

𝑐

𝑖

2𝑗1

is, the greater the influence of the corresponding

Zernike term on the shape of the wavefront is.

If the displacement of the Hartmann spot is

represented by



∆𝑥,∆𝑦



and the focal length of the

microlens array is 𝑓, the relationship of the wavefront

position shift is expressed in Equation (2).

𝜕𝑊𝑋,𝑌

𝜕𝑋



∆𝑥

𝑓

𝜕𝑊𝑋,𝑌

𝜕𝑌



∆𝑦

𝑓

(2)

The wavefront can be reconstructed by

substituting Equation (1) into Equation (2) to obtain

the Zernike coefficients.

Table 1: Specification of the wavefront sensor.

Index Paramete

Manufacturer

Pulstec Industrial Co.,

Ltd.

Model LUCUS

Measurement wavelength 589 nm

Measurement range of

concave surface

4.3 mm~46.5 mm

Measurement range of

convex surface

5.7 mm~9.5 mm

Tolerance of wavefront

incident angle

±1.1 deg

Wavefront measurement accuracy 1/100

Repeatability 1/200

Radius measurement accuracy ±10

Number of microlens array 108×80

The focal length of

the microlens array

4 mm

Data update rate 6 Hz

Focal lens NA 0.81

Figure 1: Wavefront sensor principle.

Figure 2: Relationship between wavefront and Hartmann

spot.

2.2 Zernike Polynomials

In this study, the resin mold was evaluated using

Zernike coefficients. The device can output 36 Zernike

coefficients, but this study focused on the unique ones.

Zernike coefficients are widely used in ophthalmic

optics and are often employed to assess ocular

aberrations (Salmon, 2006). The Zernike polynomials

were standardized by fringe order (Niu, 2022). Among

the Zernike coefficients shown in Table 2, "Z04" and

"Z07" exhibited the largest changes.

"Z04" indicates astigmatism, which is one of the

five types of Seidel aberrations (spherical aberration,

coma aberration, astigmatism, field curvature, and

distortion aberration) (Carvalho, 2005). When the

orthogonal coordinates in an optical system are

defined as the horizontal and vertical planes,

astigmatism occurs when there is a shift between the

focal positions of the light beam in these planes. The

resulting image can be an ellipse, a circle, or a line. In

optical lenses, astigmatism arises when the horizontal

and vertical radii of curvature differ.

"Z07" indicates coma aberration, which occurs

when light incident at an angle does not converge to

a single point on the image plane, resulting in a

conical image. This aberration is influenced by the

distance from the optical axis, significantly affecting

how the image appears through the lens.

Table 2: Zernike polynomials.

Term Pol

nomial Aberration

Z01

ρ𝑐𝑜𝑠θ

x-Tilt

Z02

ρ𝑠𝑖𝑛θ

y-Tilt

Z03

2ρ

1

Defocus

Z04

𝑐𝑜𝑠2θ

0°Primary astigmatism

Z05

𝑠𝑖𝑛2θ

45°Primary astigmatism

Z06

3ρ

2ρ𝑐𝑜𝑠θ

Primary x-coma

Z07

3ρ

2ρ𝑠𝑖𝑛θ

Primary y-coma

Z08

6ρ

6ρ

1

Primary spherical

aberration

Z09

𝑐𝑜𝑠3θ

Secondary x-trefoil

Z10

𝑠𝑖𝑛3θ

Secondary y-trefoil

PHOTOPTICS 2025 - 13th International Conference on Photonics, Optics and Laser Technology

Both of these aberrations are critical components

in the creation of contact lenses, and the

manufacturing process must be designed to minimize

their presence. By understanding that these

aberrations exist in resin molds, their relationship to

contact lens aberrations can be clarified.

2.3 Measurement Sample

2.3.1 Contact Lens

Figure 3 shows an o

verview of the contact lens.

In this

study, the contact lens and the resin mold were

measured. The refractive power of the lens is adjusted

by designing the radius of curvature. This range is

called the Optical Zone (OZ) and plays an important

role in vision correction with contact lenses. The lens

made in this study was designed with an OZ of φ5.77

mm, and the radius of curvature was variable (OZ

radius). The five different curvature radii were

prepared in Table 3. The design outside the OZ was

common to all patterns, with the radius of curvature

changed in two stages. The back surface was designed

with a single radius of curvature, R = 6.670[mm],

which was also common to all patterns.

The contact lenses were measured using the

NIMO TR1504 manufactured by Lambda-X

Ophthalmic. This device employs a technology that

combines interferometry and phase-shifting

technology using the Phase-Shifting Schlieren (PSS)

method (Joannes, 2003). It can measure the power

profile and wavefront aberration of contact lenses.

Although this device can’t measure wavefront

measurement of resin molds, it’s useful for evaluating

contact lenses.

2.3.2 Resin Mold

Figure 4 shows an overview of the fitted state of the

resin molds. The design of the concave side for the

lens front (the orange part in the figure) was valuable

as shown in Table 3. And the measurement results

with the interferometer are presented as well. The OZ

radius was adjusted in 0.500 mm increments. The

measurement range was diameter of 5 mm from the

center of the concave surface. All resin molds for the

back surface maintained the same design. The

measurement range of the convex surface was the

same as the concave one. The reflectivity of the mold

may potentially affect the measurements taken by the

wavefront sensor. Adjusting the laser power on the

measurement device, it is possible to eliminate the

influence of reflectivity. In this study, the saturated

pixels of the Hartmann spot were defined, and the

laser power was adjusted to ensure that the number of

pixels was within the specified range.

2.3.3 Polymerization

Contact lens raw materials are liquid, so solid contact

lenses are formed through polymerization.

Polymerization is carried out after pouring the raw

materials into a resin mold and fitting it into the mold.

The shape of a contact lens is defined by the gap

between two resin molds. However, if the molds

deform during polymerization, it can greatly impact

the final lens shape.

The polymerization is crucial in forming contact

lenses, and since it’s closely related to their quality,

polymerization was conducted in nitrogen at 105±5℃

for 120 minutes, which simulates the conditions

during actual polymerization.

Figure 3: Overview of the contact lens.

Table 3: Specification of resin molds.

Sample

No.

Value of OZ

radius[mm]

Measurement of

Interferometer

]

A 6.500 6.476

B 7.000 6.975

C 7.500 7.441

D 8.000 7.899

E 8.500 8.378

Figure 4: Overview of the resin mold.

Evaluation of Resin Molds Change in Design and Polymerization by Using a Wavefront Sensor

3 RESULT

3.1 Zernike Coefficients

Wavefront measurements were performed on five

samples with different OZ radius design values. Five

measurements were taken for each sample. As a result,

for Z07, the design-dependent changes in the Zernike

coefficients were confirmed before and after

polymerization. The comparison results before and

after polymerization are presented shown in Figure

5(a) ~ (c).

Figure 5(a) shows the measurement results before

polymerization. The horizontal axis represents the

Zernike coefficient terms, and the vertical axis

displays the Zernike coefficient values. This device

can output 36 Zernike coefficients. However, since

there is almost no change from Z10 onwards, they

were judged to be unnecessary for evaluating the

resin mold. It was found that Z04 exhibited different

values depending on the OZ radius design. Similarly,

the difference in Z07 represented different designs.

Although the difference in the measurement results

due to the design for Z06 was small, it was still

possible to observe the variation in the results, while

Z10 didn’t change regardless of the design.

Figure 5(b) shows the measurement results for the

resin mold after polymerization. The sample shown

in Figure 5(a) was heat-treated under the conditions

specified in Section 2.3.3, and after the

polymerization, it was measured again using a

wavefront sensor. The absolute values of each

coefficient became larger than before the

polymerization. Z07 changed regularly. Z04 and Z05

changed significantly, but the results showed a large

variance.

Figure 5(c) shows the changes in each coefficient

before and after polymerization. The changes were

calculated by subtracting the Zernike coefficient

values before polymerization from after

polymerization. It was found that the coefficient

values were generally larger after polymerization.

Z04's values shifted in the negative direction,

although there was some variance. Z07's values

increased overall, showing a tendency for the amount

of change in value to depend on the OZ radius design.

For the other values, Z05 exhibited a larger variance,

while the other coefficients showed that the Zernike

coefficients increased in absolute values.

Figure 5(a): Zernike coefficients before polymerization.

Figure 5(b): Zernike coefficients after polymerization.

Figure 5(c): Change in subtraction for Zernike coefficients.

PHOTOPTICS 2025 - 13th International Conference on Photonics, Optics and Laser Technology

3.2 Oz Radius

Figure 6 shows the measurement results of the radius

of curvature compared to the design value of the OZ

radius of the resin mold. The horizontal axis

represents the design value, while the vertical axis

represents the measured value. This comparison

illustrates the differences before and after

polymerization for each design.

Table 4 presents the measurement results and

deviations from the design value. The radius of

curvature was consistently smaller than the design

value, with the deviation increasing as the design

value of OZ radius increased.

Table 5 shows the measurement results and

shrinkage rates of the radius of curvature before and

after polymerization. The radius of curvature before

polymerization was equivalent to the values with the

interferometer shown in Table 3. And it was found

that the radius of curvature shrank further after

polymerization compared to before polymerization.

The measurement results also indicated that the larger

the design value of the OZ radius is, the greater the

shrinkage rate is, too. The polymerization-induced

shrinkage further increased the difference between

the radius of curvature of the resin mold and the

design value.

Table 4: Difference in design value.

Value of

OZ radius

[mm]

Measurement

OZ radius before

polymerization

[mm]

Difference from

design value [%]

6.500 (A) 6.482 0.3%

7.000 (B) 6.976 0.3%

7.500 (C) 7.439 0.8%

8.000 (D) 7.895 1.3%

8.500 (E) 8.371 1.5%

Figure 6: Change in each measurement radius.

Table 5: Shrinkage rate due to polymerization.

Value of

OZ radius

[mm]

Measurement

OZ radius

before

polymerization

[mm]

Measurement

OZ radius after

polymerization

[mm]

Shrinkage

Rate

[%]

6.500 (A) 6.482 6.471 0.17%

7.000 (B) 6.976 6.956 0.29%

7.500 (C) 7.439 7.411 0.38%

8.000 (D) 7.895 7.858 0.47%

8.500 (E) 8.371 8.313 0.69%

4 DISCUSSION

In this study, we proposed the method using the

wavefront sensor to evaluate resin molds used in

contact lens manufacturing. Specifically, we

measured the Zernike coefficients and radius of

curvature for five types of resin molds with different

curvature radii in the OZ range, to assess the impact

of each design difference on aberrations. We also

compared the measurement results before and after

the polymerization performed during the

manufacturing process to observe changes in

aberrations and the radius of curvature.

The difference in the curvature radius of the OZ

range caused a significant change in Z07 (coma

aberration), clearly indicating that design variations

affect aberrations. In contrast, changes in Z04

(astigmatism) will be largely influenced by

polymerization conditions, likely due to the

characteristics of the material.

Furthermore, after comparing the changes in

Zernike coefficients, we found the overall increase in

aberration values with the most significant change

observed in Z07. This means that the interaction

between design and polymerization has an influence

on the aberrations of the resin mold. As similar study,

Cheng et al. (Cheng, 2020) also used a wavefront

sensor to evaluate aberrations and analysed the

impact of molding errors on the optical performance

of lenses. Both studies share the common approach of

evaluating molding errors based on Zernike

coefficients and are considered effective methods for

quantitatively assessing molding errors during the

manufacturing process.

In addition, contact lenses were produced using

the resin molds made in this study, and their

measurements were performed using the NIMO

TR1504. The evaluation range was φ5.0 mm. Table 6

shows the measured radius of curvature of the resin

molds. Each lens refractive power was calculated

using that radius of curvature. Furthermore, each

power of contact lenses was measured by NIMO. The

Evaluation of Resin Molds Change in Design and Polymerization by Using a Wavefront Sensor

data on Table 6 are also plotted in Figure 7. The

horizontal axis represents the design value of the

radius of curvature, and the vertical axis is the

refractive power. Both the theoretical lens power and

the measured lens power were shown on the graph.

The results of this study indicate that sample C

had almost no error in lens power, confirming that the

lens was produced as designed. In contrast, samples

A and E showed differences from the design values.

The difference in the radius of curvature between the

front and back surfaces of the resin mold (maximum

and minimum values) likely caused an imbalance in

the resin thickness between the center and periphery,

which affected the shrinkage. On the other hand, the

resin thickness of sample C showed a thickness

difference of less than 10μm between the center and

periphery, which was more uniform compared to the

other samples. As a result, sample C was the most

accurately produced according to the design. Based

on these findings, to further investigate the effects of

polymerization, it is necessary to accurately measure

the thickness of the resin mold. As a method for

measuring transparent resin mold, there are some

reports about the measurement method of contact

lenses with Optical Coherence Tomography (OCT)

principles (Saeki, 2020, 2021). OCT measurements

can provide data on the thickness of the resin mold

and the front and back curvature radii inside and

outside the OZ range. While the wavefront sensor can

measure wavefront shape and curvature radius with

high precision, it cannot measure the thickness or the

shape of the back surface of the resin mold. The

impact of resin thickness is a factor in the inability to

manufacture the lenses as designed. Therefore, by

adding data on changes in resin thickness obtained

through OCT measurements, we can clarify the

influence of resin thickness on the lenses. By

combining the results of this study with OCT data, it

becomes possible to assess the impact of the non-

uniformity of resin thickness on shrinkage and lens

power. These results can provide appropriate

feedback into the design as manufacturing factors.

Table 6: Comparison of theoretical and measured values of

OZ radius and refractive power.

Value of

OZ radius

[mm]

Measurement

OZ radius after

polymerization

[mm]

Theoretical

value of

refractive

power

[D]

Measurement

refractive

power

[D]

6.500 (A) 6.471 +2.73 +4.16

7.000 (B) 6.956 -2.76 -2.28

7.500 (C) 7.411 -7.26 -7.29

8.000 (D) 7.858 -11.16 -11.72

8.500 (E) 8.313 -14.72 -15.44

Figure 7: Variation of theoretical and measured values of

OZ radius and refractive power.

In this study, the evaluation was limited to five

types of resin molds, but more diverse designs and

different molding conditions are necessary for a

comprehensive understanding. Additionally,

experiments under varying temperatures and

durations could provide more detailed insights into

the influence of polymerization. Although the

wavefront sensor used in this study enables highly

precise measurements, comparative verification with

other measurement methods remains a future

challenge.

It is anticipated that the evaluation method using

the wavefront sensor will be applied to other

materials and molding processes, further expanding

its general applicability. In particular, this method can

be applied to the evaluation of transfer accuracy in

precise resin molding such as medical devices. Cheng

et al.'s research (Cheng, 2020) evaluated aberrations

in the manufacturing process of mobile phone camera

lenses and contributed to the optimization of

manufacturing conditions. By optimizing the

manufacturing process based on the Zernike

coefficients obtained in this study, the mass

production of higher-quality contact lenses will

become feasible. In this way, the wavefront sensor-

based evaluation method can be applied to quality

control across various optical products, including

contact lenses.

5 SUMMARY

In this study, the wavefront sensor was used to

evaluate resin molds utilized in contact lens

manufacturing. Five types of resin molds that have

each different curvature radius in the OZ range were

measured. Wavefront measurements were also

PHOTOPTICS 2025 - 13th International Conference on Photonics, Optics and Laser Technology

conducted before and after polymerization to observe

their changes.

The clear trend was observed in the measurement

results due to differences of the radii of curvature in

the OZ range, and specific Zernike coefficients were

identified. It was also confirmed that the certain

Zernike coefficients Z04 and Z07 changed after

polymerization.

Additionally, the measurement results for the

radius of curvature showed values smaller than the

design values even before polymerization.

Polymerization caused the resin molds to shrink more,

making the radius of curvature even smaller. It was

found that the larger the design value is, the greater

the shrinkage rate is, too, which is leading to a larger

difference from the design value.

The results for the radius of curvature were shown

to be consistent with those obtained using a laser

interferometer, demonstrating that changes in

aberration due to differences in the resin mold design

could be effectively evaluated using Zernike

coefficients of Z01 - Z10 as parameters. This suggests

that the wavefront sensor is a useful new method for

evaluating those resin molds.

However, for the contact lenses produced using

the resin molds from this study, there was a difference

between the lens power derived from the measured

radius of curvature of the resin molds and the actual

lens power measured by NIMO. The exact cause

related to the transfer accuracy from the resin mold to

the contact lens remains unclear and will be a subject

of future investigation. There have already been

reports on methods for evaluating the shape of contact

lenses using OCT (Saeki, 2021). By combining the

results from these methods, further evaluation of the

lenses will be investigated the correlation between the

transfer accuracy of the resin mold and the final

contact lens.

REFERENCES

Rosato, D. V., Rosato, D. V., & Rosato, M. G. (2000).

Injection molding handbook. Kluwer Academic

Publishers.

Ciofu, C., & Mindru, D. T. (2013). Injection and micro

injection of polymeric plastics materials: A review.

International Journal of Modern Manufacturing

Technologies, 5(2), 21-30.

Oswald, T. A., Turng, L.-S., & Gramann, P. J. (2008).

Injection molding handbook (2nd ed.). Hanser Verlag.

Chen, C.-C. A., et al. (2017). Study on injection molding of

shell mold for aspheric contact lens fabrication.

Procedia Engineering, 184, 344–349.

Chang, T. C., & Faison, E. (2001). Shrinkage behavior and

optimization of injection molded parts studied by the

Taguchi method. Polymer Engineering and Science,

41(5), 703-709.

Atchison, D. A. (2005). Recent advances in measurement

of monochromatic aberrations of human eyes. Clinical

and Experimental Optometry, 88(1), 5-27.

Cheng, X., Yan, L., Liu, L., Cao, J., Lin, Y. J., & Hao, Q.

(2020). Fabrication-error analysis of injection-molded

aspheric elements using typical aberration terms

in transmitted wavefront with Shack–Hartmann

wavefront-sensing measurement. Optical Engineering,

59(12), 123102.

Matsuyama, T., & Ujike, T. (2004). Orthogonal aberration

functions for microlithographic optics. Optical review,

11(4), 199-207.

Salmon, T. O., & van de Pol, C. (2006). Normal-eye

Zernike coefficients and root-mean-square wavefront

errors. Journal of Cataract & Refractive Surgery,

32(12), 2064-2074.

Niu, K., & Tian, C. (2022). Zernike polynomials and their

applications. Journal of Optics, 24(12), 123001.

Carvalho, L. A. (2005). Accuracy of Zernike polynomials

in characterizing optical aberrations and the corneal

surface of the eye. Investigative ophthalmology &

visual science, 46(6), 1915-1926.

Joannes, L., Dubois, F., & Legros, J.-C. (2003). Phase-

shifting schlieren: High-resolution quantitative

schlieren that uses the phase-shifting technique

principle. Applied Optics, 42(25), 5046–5053.

Saeki, K., Huyan, D., Sawada, M., Sun, Y., Nakamura, A.,

Kimura, M., ... & Shiina, T. (2020). Measurement

algorithm for real front and back curved surfaces of

contact lenses. Applied Optics, 59(28), 9051-9059.

Saeki, K., Huyan, D., Sawada, M., Nakamura, A., Kubota,

S., Uno, K., ... & Shiina, T. (2021). Three-dimensional

measurement for spherical and nonspherical shapes of

contact lenses. Applied optics, 60(13), 3689-3698.

Saeki, K., Huyan, D., Nakamura, A., Kubota, S., Uno, K.,

Ohnuma, K., & Shiina, T. (2021). 2D and 3D

Measurement Algorithms for Real Front and Back

Curved Surfaces of Contact Lenses. In PHOTOPTICS

(pp. 73-80).

Evaluation of Resin Molds Change in Design and Polymerization by Using a Wavefront Sensor