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Dive into the research topics where Akihito Igarashi is active.

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Featured researches published by Akihito Igarashi.


Archives of Ophthalmology | 2009

Four-year follow-up of posterior chamber phakic intraocular lens implantation for moderate to high myopia.

Kazutaka Kamiya; Kimiya Shimizu; Akihito Igarashi; Fumika Hikita; Mari Komatsu

OBJECTIVE To assess the long-term clinical outcomes of implantation of a lens consisting of a biocompatible collagen copolymer (Visian implantable Collamer lens [ICL]; STAAR Surgical, Nidau, Switzerland) for moderate to high myopia. METHODS We evaluated 56 eyes of 34 patients with myopic refractive errors of -4.00 to -15.25 diopters (D) who underwent ICL implantation and routine postoperative examinations. Before and 1, 3, and 6 months and 1, 2, and 4 years after surgery, we assessed the safety, efficacy, predictability, stability, and adverse events of the surgery. RESULTS Mean (SD) logMAR uncorrected and best spectacle-corrected visual acuities were -0.03 (0.23) and -0.21 (0.09), respectively, at 4 years after surgery. The mean (SD) safety and efficacy indexes were 1.19 (0.25) and 0.83 (0.29), respectively. At 4 years, 44 (79%) and 52 (93%) of the eyes were within +/-0.5 and +/-1.0 D, respectively, of the targeted correction. Mean (SD) manifest refraction changes of -0.24 (0.57) D occurred from 1 month to 4 years after surgery. No vision-threatening complications occurred during the observation period. CONCLUSION Implantation of ICLs is safe and effective and provides predictable and stable refractive results in the treatment of moderate to high myopia during a 4-year observation period, suggesting its viability as a surgical option for the treatment of such eyes.


American Journal of Ophthalmology | 2014

Visual and refractive outcomes of femtosecond lenticule extraction and small-incision lenticule extraction for myopia.

Kazutaka Kamiya; Kimiya Shimizu; Akihito Igarashi; Hidenaga Kobashi

PURPOSE To compare the visual and refractive outcomes of femtosecond lenticule extraction (FLEx) and small-incision lenticule extraction (SMILE) in eyes with myopia. DESIGN Prospective, randomized, masked clinical trial with intraindividual comparison. METHODS This study evaluated 52 eyes of 26 consecutive patients with spherical equivalents of -4.19 ± 1.65 diopters (D) (mean ± standard deviation) who underwent FLEx in 1 eye and SMILE in the other eye by randomized assignment. Before surgery, and 1 week and 1, 3, and 6 months after surgery, we assessed safety, efficacy, predictability, stability, and adverse events of the 2 surgical techniques. RESULTS LogMAR uncorrected and corrected distance visual acuity was, respectively, -0.17 ± 0.10, -0.20 ± 0.07 in the FLEx group and -0.15 ± 0.10, -0.19 ± 0.07 in the SMILE group 6 months postoperatively. In the FLEx and SMILE groups 6 months postoperatively, 96% and 100% of eyes, respectively, were within 0.5 D of the targeted spherical equivalent correction. Changes of -0.02 ± 0.39 D and 0.00 ± 0.30 D occurred in manifest refraction from 1 week to 6 months in the FLEx and SMILE groups, respectively. No clinically significant complications occurred in the FLEx or the SMILE group. CONCLUSIONS Both FLEx and SMILE performed well in the correction of myopia throughout the 6-month observation period. FLEx may be essentially equivalent to SMILE in terms of safety, efficacy, predictability, and stability, suggesting that the presence or absence of lifting the flap does not significantly affect these visual and refractive outcomes.


Journal of Cataract and Refractive Surgery | 2008

Comparison of Collamer toric contact lens implantation and wavefront-guided laser in situ keratomileusis for high myopic astigmatism

Kazutaka Kamiya; Kimiya Shimizu; Akihito Igarashi; Mari Komatsu

PURPOSE: To compare the postoperative visual outcomes after implantation of a Collamer toric implantable contact lens (ICL) and after wavefront‐guided laser in situ keratomileusis in high myopic astigmatism. SETTING: Department of Ophthalmology, Kitasato University, Kanagawa, Japan. METHODS: This study comprised 30 eyes (18 patients) having toric ICL implantation and 24 eyes (17 patients) having wavefront‐guided LASIK (Technolas 217z) to correct high myopic astigmatism (manifest spherical equivalent [SE] ≤−6.0 diopters [D]; manifest refractive cylinder ≥1.0 D). The safety, efficacy, predictability, stability, and adverse events were assessed preoperatively and 1 week and 1, 3, and 6 months postoperatively. RESULTS: At 6 months, the mean safety index was 1.28 ± 0.25 (SD) in the ICL group and 1.01 ± 0.16 in the LASIK group and the mean efficacy index, 0.87 ± 0.15 and 0.83 ± 0.23, respectively. All eyes in the ICL group and 71% of eyes in the LASIK group were within ±1.00 D of the targeted SE correction at 6 months. The mean change in manifest refraction from 1 week to 6 months was −0.04 ± 0.24 D in the ICL group and −0.60 ± 0.49 D in the LASIK group. There were no significant complications in the ICL group; 2 eyes (8.3%) in the LASIK group required enhancement ablations. CONCLUSION: Toric ICL implantation was better than wavefront‐guided LASIK in eyes with high myopic astigmatism in almost all measures of safety, efficacy, predictability, and stability, suggesting that toric ICL implantation may become a viable surgical option to treat high myopic astigmatism.


Eye | 2012

Clinical evaluation of the additive effect of diquafosol tetrasodium on sodium hyaluronate monotherapy in patients with dry eye syndrome: a prospective, randomized, multicenter study.

Kazutaka Kamiya; M Nakanishi; Rie Ishii; Hidenaga Kobashi; Akihito Igarashi; Nobuyuki Sato; Kimiya Shimizu

PurposeTo assess the additive effect of diquafosol tetrasodium on sodium hyaluronate monotherapy in patients with dry eye syndrome.MethodsThis study evaluated 64 eyes of 32 patients (age: 62.6±12.8 years (mean±SD)) in whom treatment with 0.1% sodium hyaluronate was insufficiently responsive. The eyes were randomly assigned to one of the two regimens in each patient: topical administration of sodium hyaluronate and diquafosol tetrasodium in one eye, and that of sodium hyaluronate in the other. Before treatment, and 2 and 4 weeks after treatment, we determined tear volume, tear film break-up time (BUT), fluorescein and rose bengal vital staining scores, subjective symptoms, and adverse events.ResultsWe found a significant improvement in BUT (P=0.049, Dunnett test), fluorescein and rose bengal staining scores (P=0.02), and in subjective symptoms (P=0.004 for dry eye sensation, P=0.02 for pain, and P=0.02 for foreign body sensation) 4 weeks after treatment in the diquafosol eyes. On the other hand, we found no significant change in these parameters after treatment in the control eyes.ConclusionsIn dry eyes, where sodium hyaluronate monotherapy was insufficient, diquafosol tetrasodium was effective in improving objective and subjective symptoms, suggesting its viability as an option for the additive treatment of such eyes.


British Journal of Ophthalmology | 2012

Early clinical outcomes of implantation of posterior chamber phakic intraocular lens with a central hole (Hole ICL) for moderate to high myopia

Kimiya Shimizu; Kazutaka Kamiya; Akihito Igarashi; Tetsu Shiratani

Aim To assess the early clinical outcomes of an ICL with a central hole (Hole ICL) implantation for the correction of moderate to high myopia. Methods This study evaluated 20 eyes of 20 patients with spherical equivalents of −7.36±2.13 D (mean±SD) who underwent Hole ICL implantation. Before surgery and at 1 week and 1, 3 and 6 months after surgery, we assessed the safety, efficacy, predictability, stability and adverse events of the surgery. Results Logarithm of the minimum angle of resolution (logMAR) uncorrected visual acuity and logMAR best spectacle-corrected visual acuity were −0.20±0.12 and −0.25±0.06, respectively, 6 months after surgery. The safety and efficacy indices were 1.13±0.24 and 1.03±0.30, respectively. At 6 months, 95%, and 100% eyes were within ±0.5 and ±1.0 D of the targeted correction, respectively. Change in manifest refraction from week 1 to month 6 was 0.06±0.28 D. No significant rise in intraocular pressure (including pupillary block) or a secondary cataract occurred in any case during the period of observation. Conclusions Implantation of a newly developed Hole ICL offered good results for all measures of safety, efficacy, predictability and stability for the correction of moderate to high myopic errors, even without peripheral iridectomy, suggesting its viability as a surgical option for the treatment of such eyes.


American Journal of Ophthalmology | 2014

Eight-Year Follow-up of Posterior Chamber Phakic Intraocular Lens Implantation for Moderate to High Myopia

Akihito Igarashi; Kimiya Shimizu; Kazutaka Kamiya

PURPOSE To assess the long-term clinical outcomes of Implantable Collamer Lens (Visian ICL; STAAR Surgical) implantation for moderate to high myopia. DESIGN Retrospective observational case series. METHODS This study evaluated 41 eyes of 41 patients with myopic refractive errors of -4.00 to -15.25 diopters (D) who underwent ICL implantation and routine postoperative examinations. Before surgery, and 1 and 6 months and 1, 4 and 8 years after surgery, we assessed the safety, efficacy, predictability, stability, and adverse events of the surgery. RESULTS The safety and efficacy indices were 1.13 ± 0.27 and 0.83 ± 0.36. At 8 years, 68.3% and 85.4% of the eyes were within 0.5 and 1.0 D, respectively, of the targeted correction. Manifest refraction changes of -0.32 ± 0.73 D occurred between 1 month and 8 years. The mean endothelial cell loss from preoperative levels was 6.2% at 8 years. Two eyes (4.9%) developed clinically significant symptomatic cataract during the follow-up period. Simultaneous lens extraction and phacoemulsification with IOL implantation was successfully performed in these 2 eyes. CONCLUSIONS According to our experience, ICL implantation was overall good in measures of safety, efficacy, predictability, and stability for the correction of moderate to high myopia during the 8-year observation period, suggesting its long-term viability as a surgical option for the treatment of such eyes.


American Journal of Ophthalmology | 2009

Visual performance after implantable collamer lens implantation and wavefront-guided laser in situ keratomileusis for high myopia.

Akihito Igarashi; Kazutaka Kamiya; Kimiya Shimizu; Mari Komatsu

PURPOSE To compare postoperative visual function after implantable collamer lens (ICL; STAAR Surgical, Nidau, Switzerland) implantation and after wavefront-guided laser in situ keratomileusis (WFG-LASIK) in eyes with high myopia. DESIGN Retrospective, observational case study. METHODS We investigated 46 eyes of 33 patients undergoing ICL implantation and 47 eyes of 29 patients undergoing WFG-LASIK (Technolas217z; Bausch & Lomb, Rochester, New York, USA) for the correction of high myopia (manifest spherical equivalent < or = -6 diopters). Ocular higher-order aberrations (HOA) and contrast sensitivity (CS) function were measured by Hartmann-Shack aberrometry (KR-9000; Topcon, Tokyo, Japan) and a CS unit (VCTS-6500; Vistech Consultants Inc, Dayton, Ohio, USA) before and 3 months after surgery, respectively. From the CS, the area under the log CS function (AULCSF) was calculated. RESULTS For a 4-mm pupil, the changes in ocular coma-like aberrations, spherical-like aberrations, and total HOAs after ICL implantation were significantly less than those after WFG-LASIK (P < .001, Mann-Whitney U test). The postoperative AULCSF was significantly increased after ICL implantation (P < .001), whereas after WFG-LASIK, it was significantly decreased (P < .001). CONCLUSIONS ICL implantation induces significantly fewer ocular HOAs than WFG-LASIK. Moreover, CS was improved significantly after ICL implantation, but deteriorated after WFG-LASIK in eyes with high myopia. Thus, in the correction of high myopia, ICL implantation seems to be superior in visual performance to WFG-LASIK, suggesting that it may be a better surgical option for the treatment of such eyes.


Journal of Cataract and Refractive Surgery | 2012

Early clinical outcomes, including efficacy and endothelial cell loss, of refractive lenticule extraction using a 500 kHz femtosecond laser to correct myopia

Kazutaka Kamiya; Akihito Igarashi; Rie Ishii; Nobuyuki Sato; Hiroyuki Nishimoto; Kimiya Shimizu

PURPOSE: To assess the early clinical outcomes, including the efficacy and the endothelial cell loss, of femtosecond lenticule extraction using a 500 kHz femtosecond laser system to correct myopia. SETTING: Department of Ophthalmology, Kitasato University, Kanagawa, Japan. DESIGN: Case series. METHODS: This study evaluated eyes with a spherical equivalent of −4.26 diopters (D) ± 1.39 (SD) that had femtosecond lenticule extraction for myopia. Before surgery and 1 week and 1, 3, and 6 months after surgery, the safety, efficacy, predictability, stability, and adverse events of the surgery were assessed. RESULTS: The study enrolled 38 eyes of 20 patients. The uncorrected distance visual acuity and corrected distance visual acuity 6 months after surgery were −0.14 ± 0.10 logMAR and −0.21 ± 0.09 logMAR, respectively. The safety index was 0.96 ± 0.19 and the efficacy index, 0.82 ± 0.17. At 6 months, all eyes were within ±0.50 D of the targeted correction. The mean manifest refraction change from 1 week to 6 months was 0.02 ± 0.28 D. The endothelial cell density was 2814 ± 199 cells/mm2 preoperatively and 2762 ± 213 cells/mm2 postoperatively; the change was not significant (P = .32, Wilcoxon signed‐rank test). No vision‐threatening complications occurred during the observation period. CONCLUSIONS: Femtosecond lenticule extraction performed well in the correction of myopia. Neither significant endothelial cell loss nor serious complications occurred throughout the 6‐month follow‐up, suggesting femtosecond lenticule extraction is a viable surgical option to treat myopic eyes. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.


American Journal of Ophthalmology | 2012

Intraindividual comparison of visual performance after posterior chamber phakic intraocular lens with and without a central hole implantation for moderate to high myopia.

Kimiya Shimizu; Kazutaka Kamiya; Akihito Igarashi; Tetsu Shiratani

PURPOSE To compare postoperative visual performance after implantable Collamer lenses with and without a central hole (Hole ICL and conventional ICL) are implanted to correct moderate to high myopia. DESIGN Prospective intraindividual comparative study. PATIENTS AND METHODS This study evaluated 58 eyes of 29 patients with spherical equivalents of -7.55 ± 2.09 diopters (D) [mean ± standard deviation] who underwent Hole ICL implantation in one eye and conventional ICL implantation in the other eye by randomization assignment. Ocular higher-order aberrations (HOAs) and contrast sensitivity (CS) function were measured by Hartmann-Shack aberrometry and a contrast sensitivity unit before and 3 months after surgery, respectively. From the contrast sensitivity, the area under the log CS function was calculated. RESULTS For 4-mm and 6-mm pupils, the changes after Hole ICL implantation in coma-like aberrations, spherical-like aberrations, and total HOAs are similar to those after conventional ICL implantation (P > .05, Wilcoxon signed rank test). The postoperative area under the log CS function was significantly increased after Hole ICL implantation (P < .05), and was equivalent to that after conventional ICL implantation under photopic, mesopic, or mesopic with glare conditions. Subjective symptoms such as glare or halo were also essentially equivalent after Hole ICL and conventional ICL implantation. CONCLUSIONS A newly developed Hole ICL implantation appears to be equivalent in the induction of HOAs and CS function to conventional ICL implantation for the correction of moderate to high myopia, suggesting its viability as a surgical option for the treatment of such eyes, because it does not require additional peripheral iridotomies and may also reduce the risk of cataract formation.


American Journal of Ophthalmology | 2012

Visual Performance After Posterior Chamber Phakic Intraocular Lens Implantation and Wavefront-Guided Laser In Situ Keratomileusis for Low to Moderate Myopia

Kazutaka Kamiya; Akihito Igarashi; Kimiya Shimizu; Kazuhiro Matsumura; Mari Komatsu

PURPOSE To compare postoperative visual function after implantable collamer lens (ICL) implantation and after wavefront-guided laser in situ keratomileusis (LASIK) in eyes with low to moderate myopia. DESIGN Retrospective observational case study. PATIENTS AND METHODS We investigated 30 eyes of 20 patients undergoing ICL implantation and 64 eyes of 38 patients undergoing wavefront-guided LASIK for the correction of low to moderate myopia (manifest spherical equivalent: -3.00 to -5.88 diopters [D]). Ocular higher-order aberrations (HOAs) and contrast sensitivity (CS) function were measured by Hartmann-Shack aberrometry and a contrast sensitivity unit before and 3 months after surgery, respectively. From the contrast sensitivity, the area under the log contrast sensitivity function was calculated. RESULTS For 4-mm and 6-mm pupils, the changes in ocular third-order aberrations, fourth-order aberrations, and total HOAs after ICL implantation were significantly less than those after wavefront-guided LASIK (P < .05, Mann-Whitney U test). The postoperative area under the log contrast sensitivity function was significantly increased after ICL implantation (P < .001), whereas, after wavefront-guided LASIK, it was not significantly changed (P = .11). CONCLUSIONS ICL implantation induces significantly fewer ocular HOAs than wavefront-guided LASIK. Moreover, CS was significantly improved after ICL implantation but unchanged after wavefront-guided LASIK in eyes with low to moderate myopia. Thus, even in the correction of low to moderate myopia, ICL implantation appears to be superior in visual performance to wavefront-guided LASIK, suggesting that it may be a viable surgical option for the treatment of such eyes.

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Hidenaga Kobashi

Massachusetts Eye and Ear Infirmary

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Rie Ishii

University of Münster

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Takashi Kojima

Sapporo Medical University

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