慶 市川

Dr. 慶 市川

orcid

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 December 2024 in Journal of Cataract & Refractive Surgery
Verified
Journal Article
Open access
YKYukihito Kato
Yukihito Kato
MAMasahiko Ayaki
Masahiko Ayaki
YTYoshiki Tanaka
Yoshiki Tanaka
ATAkeno Tamaoki
Akeno Tamaoki
YSYukihiro Co Sakai
Yukihiro Co Sakai
KIKazuo Ichikawa
Kazuo Ichikawa
Purpose: To compare three biometers equipped with swept-source optical coherence tomography (OCT), including ARGOS (OCTB1), IOLMaster 700 (OCTB2), and Anterion (AS-OCTB). The primary aim was to assess the axial length (AL) acquisition success rates, and secondary aims included comparing parameters obtained from the three devices and evaluating postoperative refractive prediction errors. Setting: Chukyo Eye Clinic, Nagoya, Japan. Design: Retrospective observational study. Methods: The study included patients undergoing preoperative assessments for cataract surgery using the three biometers. The AL acquisition success rates and parameters obtained from the three devices were compared and the postoperative refractive prediction errors (defined as the difference between subjective refractive error and predicted refractive error) were assessed at one month after surgery. Results: The study included 361 eyes from 361 patients. The AL acquisition success rates for all patients were 100.0% (n=361) (OCTB1), 98.6% (n=356) (OCTB2), and 96.7% (AS-OCTB) (P < .0001), and those for nuclear sclerosis of grade 4 or higher were 100.0%, 87.8%, and 87.8%, respectively (P = .007). The AL of mature cataract was measurable only with OCTB1 using the enhanced retina visualization mode. Although there were significant differences in parameters obtained on the three devices, there were no significant differences in postoperative refractive prediction errors. Conclusions: OCTB1 demonstrated the highest AL acquisition success rate and was able to measure AL even in eyes with dense or mature cataract. AS-OCTB using a wavelength of 1300 nm showed lower AL acquisition success rates compared to the other two devices probably due to reduced light transmission through the vitreous body.

1 November 2024 in Journal of Refractive Surgery
Verified
Journal Article
Closed access
慶市慶 市川
慶 市川
YSYukihiro Sakai
Yukihiro Sakai
HTHiroto Toda
Hiroto Toda
YKYukihito Kato
Yukihito Kato
KIKazuo Ichikawa
Kazuo Ichikawa
Purpose: To describe Light Adjustable Lens (RxSight, Inc) (LAL) visual and refractive outcomes in a Japanese patient population with and without prior refractive surgery. Methods: In this retrospective chart review of patients with cataract in a private eye clinic, 34 eyes from 21 patients underwent cataract surgery with LAL implantation. Eyes underwent light treatment to adjust the patients' refraction after implantation to meet individual visual goals. Standard visual and refractive outcomes were collected. Contrast sensitivity (to assess quality of vision), clinical defocus and vergence curves (to assess range of vision), and patient satisfaction were also collected. Results: The mean prediction error of the light adjustment was −0.04 ± −0.48. Thirty-one eyes (91%) and 33 eyes (97%) were within ±0.25 and ±0.50 diopters (D) of manifest spherical equivalent target, respectively. Thirty-two eyes (94%) had residual refractive cylinder of 0.50 D or less. The full depth of focus was 3.68 D. Monocular contrast sensitivity shows frequencies equivalent to a normal population aged 50 to 60 years. The mean satisfaction score was 8.8 (scale: 1 to 10). There were no adverse events and no eyes lost corrected distance visual acuity from the light treatment. Conclusions: LALs in cataract refractive surgery hold great promise, including for the Japanese population, which have unique ocular biometrics. By providing a safe procedure and the ability for postoperative adjustments, the LAL provided a tailored approach to vision correction, ultimately improving patient outcomes and satisfaction. [ J Refract Surg . 2024;40(11):e854–e862.]

10 July 2023 in Medicina
Verified
Journal Article
Open access
PDF file
KIKazuo Ichikawa
Kazuo Ichikawa
慶市慶 市川
慶 市川
Naoki YamamotoNaoki Yamamoto
Naoki Yamamoto
RHRie Horai
Rie Horai
Background and Objectives: In this study, we aimed to compare the physical properties of hole-implantable collamer lenses (H-ICLs) and implantable phakic contact lenses (IPCLs) and investigate their flexural and cell adhesion characteristics. Materials and Methods: Transverse compression load to achieve lens flexion and static Young’s modulus were measured in H-ICLs and IPCLs using designated equipment. Load was measured both with and without restraining the optic section of the lenses. Adhesion of iHLEC-NY2 cells to the lens surfaces was examined using phase-contrast microscopy, and cell proliferation activity was evaluated using WST-8 assay. Results: The H-ICL showed a greater tendency for transverse compression load compared to IPCL, while the IPCL showed a higher Young’s modulus with respect to the force exerted on the center of the anterior surface of the optic section. The joint between the optic section and haptic support in the IPCL was found to mitigate the effects of transverse compression load. Both lens types showed minimal cell adhesion. Conclusions: Our findings indicate that H-ICLs and IPCLs exhibit distinct physical properties and adhesive characteristics. The IPCL demonstrated higher Young’s modulus and unique structural features, while the H-ICL required greater transverse compression load to achieve the flexion required to tuck the haptic supports into place behind the iris to fix the lens. The observed cell non-adhesive properties for both lens types are promising in terms of reducing complications related to cell adhesion. However, further investigation and long-term observation of IPCL are warranted to assess its stability and potential impact on the iris. These findings contribute to a better understanding of the performance and potential applications of H-ICLs and IPCLs in ophthalmology.

26 November 2024 in Bioengineering
Verified
Journal Article
Open access
PDF file
KIKazuo Ichikawa
Kazuo Ichikawa
慶市慶 市川
慶 市川
STSeiji Tokiwa
Seiji Tokiwa
YSYuki Sato
Yuki Sato
TMTomoyuki Miyazaki
Tomoyuki Miyazaki
Naoki YamamotoNaoki Yamamoto
Naoki Yamamoto
Various tips are available for phacoemulsification in cataract surgery. Evidence-based data can inform ophthalmologists, especially inexperienced ones, on tip selection. We retrospectively evaluated the energy efficiency and other parameters of two ultrasonic phacoemulsification and aspiration tips across different nuclear hardness grades in 342 cataract patients (342 eyes) with nuclear hardness grades II to IV. Surgical procedures, ultrasound settings, and instrumentation were standardized. All surgeries were performed by one experienced doctor. We compared the metal INTREPID® Balanced Tip (M-tip) with the INTREPID® Hybrid Tip (P-tip), which has a polymer coating. The M-tip required significantly less total ultrasound time and cumulative dissipated energy (CDE) than the P-tip for grades III and IV, while the P-tip had a shorter aspiration time and less estimated fluid aspirated for grade II. No differences in corneal endothelial cell loss were observed. Lens rupture rates were low: 0.47% for the M-tip and 0.78% for the P-tip. Multiple regression analysis showed that CDE increased with nuclear hardness. These findings suggest that the M-tip is efficient for harder lenses, while the P-tip may be advantageous for softer lenses, informing optimal tip selection in cataract surgery. Further research is suggested to elucidate their clinical significance.

30 July 2025 in Medicina
Verified
Journal Article
Open access
PDF file
慶市慶 市川
慶 市川
YTYoshiki Tanaka
Yoshiki Tanaka
RHRie Horai
Rie Horai
YKYu Kato
Yu Kato
KIKazuo Ichikawa
Kazuo Ichikawa
Naoki YamamotoNaoki Yamamoto
Naoki Yamamoto
Background and Objectives: Posterior chamber phakic implantable contact lenses (Phakic-ICL) are widely used for refractive correction due to their efficacy and safety, including minimal corneal endothelial cell loss. The Collamer-based EVO+ Visian implantable contact lens (ICL), manufactured from Collamer, which is a blend of collagen and hydroxyethyl methacrylate (HEMA), has demonstrated excellent long-term biocompatibility and optical clarity. Recently, hydrophilic acrylic Phakic-ICLs, such as the Implantable Phakic Contact Lens (IPCL), have been introduced. This study investigated the material differences among Phakic-ICLs and their interaction with fibronectin (FN), which has been reported to adhere to intraocular lens (IOL) surfaces following implantation. The aim was to compare Collamer, IPCL, and LENTIS lenses (used as control) in terms of FN distribution and cell adhesion using a small number of explanted Phakic-ICLs. Materials and Methods: Three lens types were analyzed: a Collamer Phakic-ICL (EVO+ Visian ICL), a hydrophilic acrylic IPCL, and a hydrophilic acrylic phakic-IOL (LENTIS). FN distribution and cell adhesion were evaluated across different regions of each lens. An in vitro FN-coating experiment was conducted to assess its effect on cell adhesion. Results: All lenses demonstrated minimal FN deposition and cellular adhesion in the central optical zone. A thin FN film was observed on the haptics of Collamer lenses, while FN adhesion was weaker or absent on IPCL and LENTIS surfaces. Following FN coating, Collamer lenses supported more uniform FN film formation; however, this did not significantly enhance cell adhesion. Conclusions: Collamer, which contains collagen, promotes FN film formation. Although FN film formation was enhanced, the low cell-adhesive properties of HEMA resulted in minimal cell adhesion even with FN presence. This characteristic may contribute to the long-term transparency and biocompatibility observed clinically. In contrast, hydrophilic acrylic materials used in IPCL and LENTIS demonstrated limited FN interaction. These material differences may influence extracellular matrix protein deposition and biocompatibility in clinical settings, warranting further investigation.

19 September 2025 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
慶市慶 市川
慶 市川
STSeiji Tokiwa
Seiji Tokiwa
YTYoshiki Tanaka
Yoshiki Tanaka
HTHIROTO TODA
HIROTO TODA
YKYukihito Kato
Yukihito Kato
Naoki YamamotoNaoki Yamamoto
Naoki Yamamoto
Background/Objectives: Cataract surgery often reveals preexisting corneal astigmatism, which can be corrected using a toric intraocular lens (T-IOL). However, postoperative T-IOL rotation may compromise correction. We investigated T-IOL rotation, focusing on deployment time and proximity to the posterior capsule (PC), using intraoperative optical coherence tomography (iOCT). Methods: Six different T-IOL models were inserted into acrylic simulated lens capsule models under different tacking durations (5 s, 30 s, and 60 s) and temperature conditions (23 °C, 28 °C, and 32 °C). The selection criteria for porcine lenses for examination required that they match human lens dimensions, typical of those used to train cataract surgeons. T-IOL misalignment due to vibration was assessed. Additionally, the impact of temporary intraocular pressure (IOP) reduction on T-IOL proximity to the PC was measured using iOCT in porcine eyes. Results: Tacking time and temperature independently affected T-IOL deployment, with shorter tacking durations and higher temperatures leading to faster deployment. Among lenses tested under identical tacking time and temperature conditions, iSert Micro Toric Aspheric 1-Piece IOL (355T3) had the slowest expansion time, while Avansee™ Preload 1-Piece Toric (YP-T3) had the fastest. Porcine eyes with a corneal white-to-white major axis < 16.0 mm fell within the 95% confidence interval for matching human lens size. Temporarily reducing IOP during surgery improved T-IOL adhesion to the PC, reducing both the occurrence and degree (from 14.0° to nearly 0°) of postoperative rotation. Conclusions: Optimal T-IOL deployment, temporary IOP reduction during surgery, and enhanced adhesion to the PC can reduce the risk and degree of T-IOL rotation. Intraoperative iOCT aids in monitoring T-IOL positioning, which is essential to prevent rotation. Accumulated fluid between the T-IOL and PC may contribute to rotation, which requires further investigation. These findings provide practical strategies for enhancing T-IOL stability and improving the effectiveness of astigmatism correction in cataract surgery.