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"Ichikawa, Kazuo"
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Comparison of angle-closure detection between automated gonioscopy and anterior-segment optical coherence tomography
2025
To investigate the concordance between angle-closure assessments based on GS-1 gonioscope images and those obtained with anterior-segment optical coherence tomography.
Retrospective clinical study.
We included 33 patients (53 eyes) who visited Chukyo Eye Clinic during 2020-2024, were suspected of having angle closure, and underwent anterior-segment optical coherence tomography (CASIA2 Advance STAR Analyzer) and GS-1 examinations. The 16-directional images captured with the GS-1 were divided into two halves, creating 32 directions, which were rearranged to correspond with those obtained via anterior-segment optical coherence tomography. Agreement between evaluations was analyzed using Cohen's κ, and the area under the receiver operating characteristic curve was evaluated. Anterior-segment optical coherence tomography images were manually corrected, and eyes with areas classified as \"narrow\" or \"closed\" were categorized as angle closure. With the GS-1, two glaucoma specialists independently reviewed the images. Areas in which the posterior trabecular meshwork was obscured in more than half of the image (Scheie classification grades III-IV) were judged indicative of angle closure.
We included 1,660 directions from 53 eyes in the agreement analysis. The proportion of directions judged as angle closure was 57.0% with anterior-segment optical coherence tomography and 46.1% with the GS-1. Cohen's κ for inter-test agreement was 0.173 (95% confidence interval: 0.128-0.218), and the area under the receiver operating characteristic curve was 0.588 (95% confidence interval: 0.561-0.615).
Analyses using anterior-segment optical coherence tomography yielded more frequent classifications of angle closure than evaluations based on GS-1 gonioscopic images.
Journal Article
Evaluation of visual function within the central 10 degrees using IMOvifa™ 24plus (1-2)
2025
The IMOvifa™ perimeter with a 24plus (1-2) testing mode has additional measurement points within the central 10 degrees, which may help evaluate the visual field within this area. Here, we comparatively evaluated the IMOvifa™ 24plus (1-2) and HFA 10-2 for the first time.
We included 30 patients (48 eyes) who underwent HFA 24-2 Swedish Interactive Threshold Algorithm Standard and IMOvifa™ 24plus (1-2) Ambient Interactive Zippy Estimated tests on the same day and HFA 10-2 within six months. We used Spearman's rank correlation coefficient to analyze the mean deviation (MD) and pattern standard deviation (PSD) between HFA 10-2 and IMOvifa™. The central 10-degree visual field was divided into four sectors, and concordance of visual field defects between IMOvifa™ 24plus (1-2) and HFA 10-2 was evaluated using kappa analysis. Additionally, all sectors showing a sensitivity of 0 dB on the HFA 24-2 were assessed for the presence and agreement of residual visual field in HFA 10-2 and IMOvifa™ 24plus (1-2).
The MD (0.843/0.804) and PSD (0.852/0.763) of IMOvifa™ 24plus (1-2) and HFA 24-2 correlated strongly with those of HFA 10-2. Regarding the ability to detect visual field defects within the central 10 degrees, agreement with HFA 10-2 was κ = 0.715 (0.611,0.819) and 0.754 (0.654,0.854) for IMOvifa™ 24plus (1-2) and HFA 24-2, respectively. In the evaluation of residual visual field, IMOvifa™ 24plus (1-2) detected residual visual function in 100% of cases where HFA 10-2 indicated residual function.
The IMOvifa™ 24plus (1-2) may have a higher ability to detect defects in certain areas of the visual field, compared with HFA 24-2, and may also detect residual visual function. However, the IMOvifa™ 24plus (1-2) is difficult to substitute for the 10-2 test, as the 10-2 test is necessary for evaluating visual field defects within the central 10 degrees.
Journal Article
Comparison of Adhesion of Immortalized Human Iris-Derived Cells and Fibronectin on Phakic Intraocular Lenses Made of Different Polymer Base Materials
by
Yamamoto, Naoki
,
Horai, Rie
,
Ichikawa, Kazuo
in
Cataracts
,
Cell adhesion
,
Cell adhesion & migration
2025
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.
Journal Article
Multicenter clinical outcomes of hole implantable collamer lens implantation in middle-aged patients
2022
To assess the multicenter clinical outcomes of the implantation of hole implantable collamer lens (Hole ICL, ICL KS-AquaPORTTM; STAAR Surgical, Nidau, Switzerland) in patients of 45 years or more. We retrospectively assessed the surgery’s safety, efficacy, predictability, stability, and adverse events before surgery and after the surgery at 1 week; 1, 3, and 6 months; and 1 year, followed by once every year for approximately 2.2 years. A total of 118 eyes of 65 patients aged 45–65 years with myopic refractive errors ranging from − 2.13 to − 18.75 diopters (D) underwent hole ICL implantation and routine postoperative examinations. The average observation period was 2.2 ± 1.0 years. The safety and efficacy indices were 1.08 ± 0.21 and 0.87 ± 0.25, respectively. Manifest refraction changes of − 0.20 ± 0.43 D occurred from 1 month to the final visit after ICL implantation. Eight eyes (6.8%) developed asymptomatic anterior subcapsular cataract (ASC) immediately after surgery, and three eyes (2.5%) developed clinically significant symptomatic nuclear cataracts during the follow-up period. According to our experience, hole ICL implantation offered favorable outcomes in all measures of safety, efficacy, predictability, and stability, even in middle-aged patients, during the 2.2-year observation period.
Journal Article
Comparison of INTREPID® balanced and hybrid tips on anterior capsule rupture in ex vivo porcine eyes
by
Yamamoto, Naoki
,
Ichikawa, Reiko
,
Tanaka, Yoshiki
in
Biology and Life Sciences
,
Care and treatment
,
Cataract
2023
Phacoemulsification has emerged as the global standard for cataract surgery, and various novel methods, tools, and agents have promoted surgical efficiency and reduced complications. Conventionally, the phaco tip, which cleaves and aspirates the cataractous lens, has been mainly constructed of metal. In this study, the risk of anterior capsule rupture was evaluated under conditions of different power modes, longitudinal (Mode-L), torsional (Mode-T), or both (Mode-LT), and different aspiration powers (0 or 200 mmHg), using a traditional metal phaco tip (Group-M) or a new phaco tip with a high-strength polymer overmold on the needle edge (Group-P), which was developed to reduce the risk of capsule rupture. One hundred twenty porcine eyes were used for experiments within a setting of typical human physiological intraocular pressure. We found that Group-M showed capsule rupture with a smaller ultrasound power than did Group-P, regardless of power mode or aspiration power. In Group-M, there was no significant difference in risk of capsule rupture among power modes, however in Group-P, capsule rupture was least likely to occur with Mode-T. These results provide useful information for inexperienced ophthalmologists to improve surgical safety.
Journal Article
Prediction of anterior chamber volume after implantation of posterior chamber phakic intraocular lens
by
Kazuo Ichikawa
,
Yuki Takagi
,
Takashi Kojima
in
Adult
,
Anterior Chamber
,
Anterior chamber (Eye)
2020
To predict the anterior chamber volume (ACV) after implantable collamer lens (ICL) implantation based on ICL size and parameters of anterior segment optical coherence tomography (AS-OCT).
Retrospective study.
This study included 222 eyes of 222 patients who underwent ICL implantation at Nagoya Eye Clinic. The patients were divided into two groups: prediction group, for creating the prediction equation (148 eyes, mean age: 32.11 ± 8.04 years), and verification group, for verifying the equation (74 eyes, mean age: 33.03 ± 6.74 years). The angle opening distance (AOD), anterior chamber width (ACW), ACV, anterior chamber depth, lens vault, angle-to-angle distance, angle recess area, and trabecular iris space area were calculated using AS-OCT. A stepwise multiple regression analysis was performed. After the creation of the prediction equation, its accuracy was verified in the verification group.
The ACV, AOD750, ACW, and ICL size were selected as explanatory variables to predict postoperative ACV. Mean predicted (114.2 ± 21.83 mm3) and actual postoperative ACVs (116.1 ± 25.41 mm3) were not significantly different (P = 0.269); absolute error was 10.59 ± 9.13 mm3. In addition, there was high correlation between actual and predictive ACV (adjusted R2 = 0.6996, p < 0.0001). Bland-Altman plot revealed that there was no addition or proportional error between predicted and actual postoperative ACV.
Postoperative ACV was accurately predicted using AS-OCT parameters and ICL size. This prediction equation may be useful for making decisions regarding ICL size.
Journal Article
Flexural and Cell Adhesion Characteristic of Phakic Implantable Lenses
by
Yamamoto, Naoki
,
Horai, Rie
,
Ichikawa, Kazuo
in
Cataracts
,
Cell adhesion & migration
,
Cell growth
2023
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.
Journal Article
Comparison of the efficacy and invasiveness of manual and automated gonioscopy
by
Mitsunori Watanabe
,
Kazuo Ichikawa
,
Ryo Asano
in
Anterior Chamber
,
Automation
,
Biology and Life Sciences
2023
To compare the efficacy and invasiveness of manual gonioscopy and automated 360-degree gonioscopy.
Manual and automated gonioscopy were performed on 70 patients with glaucoma. Manual gonioscopy was performed by a glaucoma specialist and an ophthalmology resident, and automated gonioscopy (GS-1) was performed by orthoptists. We compared the examination time for acquiring gonioscopic images (GS-1: 16 directions; manual gonioscopy: 8 directions). Furthermore, we compared the pain and discomfort scores during the examination using the Individualized Numeric Rating Scale. Among the images acquired by automated gonioscopy, we also evaluated the percentages of acquired images that could be used to determine the angle opening condition.
The examination time was not significantly different between manual (80.2±28.7) and automated gonioscopy (94.7±82.8) (p = 0.105). The pain score of automated gonioscopy (0.22±0.59) was significantly lower than that of manual gonioscopy (0.55±1.11) (p = 0.025). The discomfort score was not significantly different between manual (1.34±1.90) and automated gonioscopy (1.06±1.50) (p = 0.165). Automated gonioscopy successfully acquired clear gonioscopic images in 93.4% of the total images.
Automated gonioscopy is comparable in examination time and invasiveness to manual gonioscopy and may be useful for 360-degree iridocorneal angle evaluation.
Journal Article
Multicenter survey on implantable collamer lens dislocation
by
Kamiya, Kazutaka
,
Shimizu, Kimiya
,
Nakamura, Tomoaki
in
Accidental Falls - statistics & numerical data
,
Adult
,
Athletic Injuries - complications
2022
This study aimed to investigate the incidence, patient background, and postoperative prognosis of implantable collamer lens (ICL) dislocation. We retrospectively reviewed all cases of ICL dislocation at four major refractive surgery centers in Japan until December 2019. The incidence, patient background, cause of dislocation, complications of repositioning surgery, and postoperative visual function were investigated. Seven ICL dislocations [0.072% of total ICL-implanted eyes (9775 eyes)] occurred at an average of 28.6 months (11–82 months) postoperatively. All patients were male. Five eyes were injured during sports activities, one due to a fall from a bicycle, and another due to ocular blunt trauma caused by a mortuary tablet. Two patients had re-dislocation in the same eye. Retinal detachment occurred after repositioning surgery in one patient, and scleral buckling surgery was performed without ICL removal. ICL dislocation is a rare complication of ICL surgery; repositioning surgery is effective, but retinal complications may occur.
Journal Article
Age-related changes of color visual acuity in normal eyes
2021
To evaluate the age-related change in color visual acuity (CVA) in normal eyes.
In total, 162 normal eyes (162 subjects, women: 52, men: 110, age range: 15-68 years) with best-corrected visual acuity (BCVA) ≥20/13 were enrolled. Fifteen colors from the New Color Test (chroma 6) were applied to Landolt \"C\" rings, white point D65 was applied as background, and a luminance of 30 cd/m2 was set for both the rings and the background. These rings were used to measure the chromatic spatial discrimination acuity as the CVA value, while changing the stimulus size. Correlations of the CVA value of each color and age were evaluated. Mean CVA values of all 15 colors (logarithm of the minimum angle of resolution) were compared between age groups in 10-year increments.
Nine CVA values (red, yellow-red, red-yellow, green, blue-green, green-blue, purple, red-purple, and purple-red) were negatively correlated with age (all p<0.05); the remaining six (yellow, green-yellow, yellow-green, blue, purple-blue, and blue-purple), as well as BCVA were not. The age groups with the best to worst mean CVA values of 15 colors were as follows: 20-29 (mean ± standard deviation, 0.303 ± 0.113), 30-39 (0.324 ± 0.096), 10-19 (0.333 ± 0.022), 50-59 (0.335 ± 0.078), 40-49 (0.339 ± 0.096), and 60-69 (0.379 ± 0.125) years. There were statistically significant differences between mean CVA values of the following groups: 20-29 and 40-49 years; 20-29 and 60-69 years; 30-39 and 60-69 years (all p<0.01).
The CVA values related to the medium/long-wavelength-sensitive cones were more susceptible to aging than those related to the short-wavelength-sensitive cones. This differed from previous reports, and may be related to the difference in the range of foveal cone function evaluated with each examination.
Journal Article