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Tetsuro Oshika - One of the best experts on this subject based on the ideXlab platform.
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influence of cycloplegia with topical cyclopentolate on higher order Aberrations in myopic children
Eye, 2014Co-Authors: Takahiro Hiraoka, Miyuki Ogata, Kazunori Miyata, Yasuko Nakamura, Fumiki Okamoto, Tetsuro OshikaAbstract:To investigate the influence of cycloplegia with topical cyclopentolate on wavefront Aberrations in myopic children. This is a prospective, comparative study. Twenty-eight myopic children with a mean age of 7.25±2.55 were enrolled in this study. We evaluated refraction and wavefront Aberrations before and after cycloplegia with 1% cyclopentolate hydrochloride. Ocular and corneal Aberrations were simultaneously measured and compared with each other. Individual Zernike components were also analyzed up to the sixth order. All these parameters were compared before and after cycloplegia. Ocular higher-order Aberrations (HOAs) significantly increased after cycloplegia (P=0.012 for spherical-like and P=0.015 for total HOAs). Corneal HOAs did not change after cycloplegia. When corneal and ocular HOAs were compared, the ocular HOAs were significantly smaller than the corneal HOAs in spherical-like Aberrations (P<0.001) and total HOAs (P=0.006). As for individual Zernike components, ocular Aberration generally showed smaller or equivalent values in comparison with corneal Aberration. In addition, each Zernike component showed a large standard deviation. Internal optics compensates for corneal HOAs in myopic children, and paralysis of tonic accommodation with cyclopentolate considerably affects ocular HOAs. However, inter-individual variation in each Zernike component is quite large in myopic children.
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influence of tilt and decentration of scleral sutured intraocular lens on ocular higher order wavefront Aberration
British Journal of Ophthalmology, 2007Co-Authors: Tetsuro Oshika, Kazunori Miyata, Tadatoshi Tokunaga, Tomokazu Samejima, C Okamoto, Gentaro Sugita, Yuko IshiiAbstract:Aim: To investigate the influence of tilt and decentration of scleral-sutured intraocular lenses (IOLs) on ocular higher-order wavefront Aberrations. Methods: In 45 eyes of 36 patients who had undergone scleral suture fixation of posterior chamber IOL, tilt and decentration of IOLs were determined by Scheimpflug videophotography, and higher-order Aberration for a 4-mm pupil was measured using the Hartmann–Shack aberrometer. In another 100 eyes of 100 patients after standard cataract surgery with posterior chamber IOL implantation, ocular higher-order Aberration was measured. Results: In eyes with scleral-sutured IOL, the mean (SD) tilt angle and decentration were 4.43° (3.02°) and 0.279 (0.162) mm, respectively. Ocular coma-like Aberration in the sutured IOL group was 0.324 (0.170) µm, which was significantly greater than that of the standard cataract surgery group (0.169 (0.061) µm, p Conclusion: In eyes with scleral-sutured posterior chamber IOL, tilting of the lens induces considerable amount of ocular coma-like Aberrations.
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contrast sensitivity function and ocular higher order wavefront Aberrations in normal human eyes
Ophthalmology, 2006Co-Authors: Tetsuro Oshika, Tadatoshi Tokunaga, Tomokazu Samejima, C Okamoto, Kazunori MiyataAbstract:Purpose To investigate the relation between contrast sensitivity function and ocular higher-order wavefront Aberrations in normal human eyes. Study Design Prospective observational case series. Participants Three hundred seven eyes of 161 normal subjects, ranging in age from 15 to 60 years (30.9±8.0 [mean ± standard deviation]). Methods Ocular higher-order Aberrations were measured for a 4-mm pupil using the Hartmann–Shack wavefront analyzer. The root-mean-square of the third- and fourth-order Zernike coefficients was used to represent comalike and spherical-like Aberrations, respectively. We measured contrast sensitivity, low-contrast visual acuity (VA), and letter contrast sensitivity. From the contrast sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. Pupil diameter in a photopic condition was recorded using a digital camera. Results Multiple linear regression analysis revealed that comalike Aberration ( P = 0.002) was significantly associated with AULCSF, but spherical-like Aberration ( P = 0.200), age ( P = 0.185), and photopic pupil diameter ( P =0.252) were not. Comalike Aberration showed a significant correlation with low-contrast VA ( P P = 0.293), age ( P = 0.266), and pupil diameter ( P = 0.756) did not. Comalike Aberration was found to be significantly associated with letter contrast sensitivity ( P P =0.082), age ( P = 0.370), and pupil diameter ( P = 0.160) were not. Conclusions In normal human eyes, comalike Aberration of the eye significantly influences contrast sensitivity function.
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influence of pupil diameter on the relation between ocular higher order Aberration and contrast sensitivity after laser in situ keratomileusis
Investigative Ophthalmology & Visual Science, 2006Co-Authors: Tetsuro Oshika, Kazunori Miyata, Tadatoshi Tokunaga, Tomokazu Samejima, Keisuke Kawana, Yuichi KajiAbstract:PURPOSE To investigate the influence of pupil diameter on the relation between induced changes in ocular higher-order wavefront Aberrations and changes in contrast sensitivity by conventional laser in situ keratomileusis (LASIK) for myopia. METHODS In 215 eyes of 117 patients (age, 33.2 +/- 8.3 years) undergoing LASIK for myopia of -1.25 to -13.5 D (-5.28 +/- 2.55 D), ocular wavefront Aberrations and contrast sensitivity function were determined before and 1 month after surgery. Preoperative photopic pupil diameter was measured with a digital camera. Ocular higher-order Aberrations were measured for a 4-mm pupil with a Hartmann-Shack wavefront analyzer. The root-mean-square (RMS) of the third- and fourth-order Zernike coefficients was used to represent coma- and spherical-like Aberration, respectively. From the contrast-sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. RESULTS One hundred five eyes had a photopic pupil diameter of 4 mm or larger, and the remaining 110 had a photopic pupil diameter smaller than 4 mm. There were no statistically significant differences in the background clinical data between these two groups. In the eyes with a photopic pupil diameter of 4 mm or larger, the changes in third-order comalike Aberrations did not correlate with the changes in AULCSF (Pearson correlation coefficient, r = -0.037, P = 0.723) and 10% low-contrast visual acuity (r = 0.125, P = 0.224), but fourth-order spherical-like Aberrations correlated significantly with the changes in AULCSF (r = -0.229, P = 0.024) and 10% low-contrast visual acuity (r = 0.221, P = 0.038). In the eyes with photopic pupil size smaller than 4 mm, there were significant correlations between the changes in comalike Aberrations and the changes in AULCSF (r = -0.487, P < 0.001) and 10% low-contrast visual acuity (r = 0.310, P = 0.003), but spherical-like Aberrations showed no correlation with the changes in AULCSF (r = -0.078, P = 0.485) and 10% low-contrast visual acuity (r = 0.208, P = 0.158). CONCLUSIONS In eyes with larger photopic pupil diameter, increases in spherical-like Aberration dominantly affect contrast sensitivity, whereas in eyes with smaller pupil size, changes in coma-like Aberration exert greater influence on visual performance.
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Comparison of corneal wavefront Aberrations after photorefractive keratectomy and laser in situ keratomileusis
American journal of ophthalmology, 1999Co-Authors: Tetsuro Oshika, Stephen D. Klyce, Raymond A. Applegate, Howard C. Howland, M.alaa El DanasouryAbstract:Abstract PURPOSE: To compare changes in the corneal wavefront Aberrations after photorefractive keratectomy and laser in situ keratomileusis. METHODS: In a prospective randomized study, 22 patients with bilateral myopia received photorefractive keratectomy on one eye and laser in situ keratomileusis on the other eye. The procedure assigned to each eye and the sequence of surgery for each patient were randomized. Corneal topography measurements were performed preoperatively, 2 and 6 weeks, 3, 6, and 12 months after surgery. The data were used to calculate the wavefront Aberrations of the cornea for both small (3-mm) and large (7-mm) pupils. RESULTS: Both photorefractive keratectomy and laser in situ keratomileusis significantly increased the total wavefront Aberrations for 3- and 7-mm pupils, and values did not return to the preoperative level throughout the 12-month follow-up period. For a 3-mm pupil, there was no statistically significant difference between photorefractive keratectomy and laser in situ keratomileusis at any postoperative point. For a 7-mm pupil, the post–laser in situ keratomileusis eyes exhibited significantly larger total Aberrations than the post–photorefractive keratectomy eyes, where a significant intergroup difference was observed for spherical-like Aberration, but not for coma-like Aberration. This discrepancy seemed to be attributable to the smaller transition zone of the laser ablation in the laser in situ keratomileusis procedure. Before surgery, simulated pupillary dilation from 3 to 7 mm caused a five- to six-fold increase in the total Aberrations. After surgery, the same dilation resulted in a 25- to 32-fold increase in the photorefractive keratectomy group and a 28- to 46-fold increase in the laser in situ keratomileusis group. For a 3-mm pupil, the proportion of coma-like Aberration increased after both photorefractive keratectomy and laser in situ keratomileusis. For a 7-mm pupil, coma-like Aberration was dominant before surgery, but spherical-like Aberration became dominant postoperatively. CONCLUSIONS: Both photorefractive keratectomy and laser in situ keratomileusis increase the wavefront Aberrations of the cornea and change the relative contribution of coma- and spherical-like Aberrations. For a large pupil, laser in situ keratomileusis induces more spherical Aberrations than photorefractive keratectomy. This finding could be attributable to the smaller transition zone of the laser ablation in the laser in situ keratomileusis procedure.
M Arif - One of the best experts on this subject based on the ideXlab platform.
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spot size and quality of scanning laser correction of higher order wavefront Aberrations
Journal of Cataract and Refractive Surgery, 2002Co-Authors: David Huang, M ArifAbstract:Abstract Purpose To investigate the effect of laser spot size on the outcome of Aberration correction with scanning laser corneal ablation. Setting Cleveland Clinic Foundation, Cleveland, Ohio, USA. Methods Corrections of wavefront Aberrations of Zernike modes from the second to eighth order were simulated. Gaussian and top-hat beams of 0.6 to 2.0 mm full-width-half-maximum diameters were modeled. The fractional correction and secondary Aberration (distortion) were evaluated. Results Using a distortion/correction ratio of less than 0.5 as a cutoff for adequate performance, a 2.0 mm or smaller beam was adequate for spherocylindrical correction (Zernike second order), a 1.0 mm or smaller beam was adequate for correction of up to fourth-order Zernike modes, and a 0.6 mm or smaller beam was adequate for correction of up to sixth-order Zernike modes. Conclusions Since ocular Aberrations above the Zernike fourth order are relatively insignificant in normal eyes, current scanning lasers with a beam diameter of 1.0 mm or less are theoretically capable of eliminating most higher-order Aberrations.
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spot size and quality of scanning laser correction of higher order wavefront Aberrations
Journal of Refractive Surgery, 2001Co-Authors: David Huang, M ArifAbstract:PURPOSE To investigate the effect of laser spot size on the outcome of Aberration correction with scanning laser corneal ablation. METHODS Numerical simulation of ablation outcome. RESULTS Correction of wavefront Aberrations of Zernike modes from second to eighth order were simulated. Gaussian and top-hat beams of 0.6 to 2.0-mm full-width-half-maximum diameters were modeled. The fractional correction and secondary Aberration (distortion) were evaluated. Using a distortion/correction ratio of less than 0.5 as a cutoff for adequate performance, we found that a 2 mm or smaller beam is adequate for spherocylindrical correction (Zernike second order), a 1 mm or smaller beam is adequate for correction of up to fourth order Zernike modes, and a 0.6 mm or smaller beam is adequate for correction of up to sixth order Zernike modes. CONCLUSIONS Since ocular Aberrations above Zernike fourth order are relatively insignificant, current scanning lasers with a beam diameter of 1 mm or less are theoretically capable of eliminating most of the higher order Aberrations of the eye.
David Huang - One of the best experts on this subject based on the ideXlab platform.
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spot size and quality of scanning laser correction of higher order wavefront Aberrations
Journal of Cataract and Refractive Surgery, 2002Co-Authors: David Huang, M ArifAbstract:Abstract Purpose To investigate the effect of laser spot size on the outcome of Aberration correction with scanning laser corneal ablation. Setting Cleveland Clinic Foundation, Cleveland, Ohio, USA. Methods Corrections of wavefront Aberrations of Zernike modes from the second to eighth order were simulated. Gaussian and top-hat beams of 0.6 to 2.0 mm full-width-half-maximum diameters were modeled. The fractional correction and secondary Aberration (distortion) were evaluated. Results Using a distortion/correction ratio of less than 0.5 as a cutoff for adequate performance, a 2.0 mm or smaller beam was adequate for spherocylindrical correction (Zernike second order), a 1.0 mm or smaller beam was adequate for correction of up to fourth-order Zernike modes, and a 0.6 mm or smaller beam was adequate for correction of up to sixth-order Zernike modes. Conclusions Since ocular Aberrations above the Zernike fourth order are relatively insignificant in normal eyes, current scanning lasers with a beam diameter of 1.0 mm or less are theoretically capable of eliminating most higher-order Aberrations.
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spot size and quality of scanning laser correction of higher order wavefront Aberrations
Journal of Refractive Surgery, 2001Co-Authors: David Huang, M ArifAbstract:PURPOSE To investigate the effect of laser spot size on the outcome of Aberration correction with scanning laser corneal ablation. METHODS Numerical simulation of ablation outcome. RESULTS Correction of wavefront Aberrations of Zernike modes from second to eighth order were simulated. Gaussian and top-hat beams of 0.6 to 2.0-mm full-width-half-maximum diameters were modeled. The fractional correction and secondary Aberration (distortion) were evaluated. Using a distortion/correction ratio of less than 0.5 as a cutoff for adequate performance, we found that a 2 mm or smaller beam is adequate for spherocylindrical correction (Zernike second order), a 1 mm or smaller beam is adequate for correction of up to fourth order Zernike modes, and a 0.6 mm or smaller beam is adequate for correction of up to sixth order Zernike modes. CONCLUSIONS Since ocular Aberrations above Zernike fourth order are relatively insignificant, current scanning lasers with a beam diameter of 1 mm or less are theoretically capable of eliminating most of the higher order Aberrations of the eye.
Peter Christiaan Tiemeijer - One of the best experts on this subject based on the ideXlab platform.
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breaking the spherical and chromatic Aberration barrier in transmission electron microscopy
Ultramicroscopy, 2005Co-Authors: B Freitag, Stephan Kujawa, J Ringnalda, Peter Christiaan TiemeijerAbstract:Abstract Since the invention of transmission electron microscopy (TEM) in 1932 (Z. Physik 78 (1932) 318) engineering improvements have advanced system resolutions to levels that are now limited only by the two fundamental Aberrations of electron lenses; spherical and chromatic Aberration (Z. Phys. 101 (1936) 593). Since both Aberrations scale with the dimensions of the lens, research resolution requirements are pushing the designs to lenses with only a few mm space in the pole-piece gap for the specimen. This is in conflict with the demand for more and more space at the specimen, necessary in order to enable novel techniques in TEM, such as He-cooled cryo electron microscopy, 3D-reconstruction through tomography (Science 302 (2003) 1396) TEM in gaseous environments, or in situ experiments (Nature 427 (2004) 426). All these techniques will only be able to achieve Angstrom resolution when the Aberration barriers have been overcome. The spherical Aberration barrier has recently been broken by introducing spherical Aberration correctors (Nature 392 (1998) 392, 418 (2002) 617), but the correction of the remaining chromatic Aberrations have proved to be too difficult for the present state of technology (Optik 57 (1980) 73). Here we present an alternative and successful method to eliminate the chromatic blur, which consists of monochromating the TEM beam (Inst. Phys. Conf. Ser. 161 (1999) 191). We show directly interpretable resolutions well below 1 A for the first time, which is significantly better than any TEM operating at 200 KV has reached before.
Kazunori Miyata - One of the best experts on this subject based on the ideXlab platform.
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influence of cycloplegia with topical cyclopentolate on higher order Aberrations in myopic children
Eye, 2014Co-Authors: Takahiro Hiraoka, Miyuki Ogata, Kazunori Miyata, Yasuko Nakamura, Fumiki Okamoto, Tetsuro OshikaAbstract:To investigate the influence of cycloplegia with topical cyclopentolate on wavefront Aberrations in myopic children. This is a prospective, comparative study. Twenty-eight myopic children with a mean age of 7.25±2.55 were enrolled in this study. We evaluated refraction and wavefront Aberrations before and after cycloplegia with 1% cyclopentolate hydrochloride. Ocular and corneal Aberrations were simultaneously measured and compared with each other. Individual Zernike components were also analyzed up to the sixth order. All these parameters were compared before and after cycloplegia. Ocular higher-order Aberrations (HOAs) significantly increased after cycloplegia (P=0.012 for spherical-like and P=0.015 for total HOAs). Corneal HOAs did not change after cycloplegia. When corneal and ocular HOAs were compared, the ocular HOAs were significantly smaller than the corneal HOAs in spherical-like Aberrations (P<0.001) and total HOAs (P=0.006). As for individual Zernike components, ocular Aberration generally showed smaller or equivalent values in comparison with corneal Aberration. In addition, each Zernike component showed a large standard deviation. Internal optics compensates for corneal HOAs in myopic children, and paralysis of tonic accommodation with cyclopentolate considerably affects ocular HOAs. However, inter-individual variation in each Zernike component is quite large in myopic children.
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influence of tilt and decentration of scleral sutured intraocular lens on ocular higher order wavefront Aberration
British Journal of Ophthalmology, 2007Co-Authors: Tetsuro Oshika, Kazunori Miyata, Tadatoshi Tokunaga, Tomokazu Samejima, C Okamoto, Gentaro Sugita, Yuko IshiiAbstract:Aim: To investigate the influence of tilt and decentration of scleral-sutured intraocular lenses (IOLs) on ocular higher-order wavefront Aberrations. Methods: In 45 eyes of 36 patients who had undergone scleral suture fixation of posterior chamber IOL, tilt and decentration of IOLs were determined by Scheimpflug videophotography, and higher-order Aberration for a 4-mm pupil was measured using the Hartmann–Shack aberrometer. In another 100 eyes of 100 patients after standard cataract surgery with posterior chamber IOL implantation, ocular higher-order Aberration was measured. Results: In eyes with scleral-sutured IOL, the mean (SD) tilt angle and decentration were 4.43° (3.02°) and 0.279 (0.162) mm, respectively. Ocular coma-like Aberration in the sutured IOL group was 0.324 (0.170) µm, which was significantly greater than that of the standard cataract surgery group (0.169 (0.061) µm, p Conclusion: In eyes with scleral-sutured posterior chamber IOL, tilting of the lens induces considerable amount of ocular coma-like Aberrations.
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contrast sensitivity function and ocular higher order wavefront Aberrations in normal human eyes
Ophthalmology, 2006Co-Authors: Tetsuro Oshika, Tadatoshi Tokunaga, Tomokazu Samejima, C Okamoto, Kazunori MiyataAbstract:Purpose To investigate the relation between contrast sensitivity function and ocular higher-order wavefront Aberrations in normal human eyes. Study Design Prospective observational case series. Participants Three hundred seven eyes of 161 normal subjects, ranging in age from 15 to 60 years (30.9±8.0 [mean ± standard deviation]). Methods Ocular higher-order Aberrations were measured for a 4-mm pupil using the Hartmann–Shack wavefront analyzer. The root-mean-square of the third- and fourth-order Zernike coefficients was used to represent comalike and spherical-like Aberrations, respectively. We measured contrast sensitivity, low-contrast visual acuity (VA), and letter contrast sensitivity. From the contrast sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. Pupil diameter in a photopic condition was recorded using a digital camera. Results Multiple linear regression analysis revealed that comalike Aberration ( P = 0.002) was significantly associated with AULCSF, but spherical-like Aberration ( P = 0.200), age ( P = 0.185), and photopic pupil diameter ( P =0.252) were not. Comalike Aberration showed a significant correlation with low-contrast VA ( P P = 0.293), age ( P = 0.266), and pupil diameter ( P = 0.756) did not. Comalike Aberration was found to be significantly associated with letter contrast sensitivity ( P P =0.082), age ( P = 0.370), and pupil diameter ( P = 0.160) were not. Conclusions In normal human eyes, comalike Aberration of the eye significantly influences contrast sensitivity function.
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influence of pupil diameter on the relation between ocular higher order Aberration and contrast sensitivity after laser in situ keratomileusis
Investigative Ophthalmology & Visual Science, 2006Co-Authors: Tetsuro Oshika, Kazunori Miyata, Tadatoshi Tokunaga, Tomokazu Samejima, Keisuke Kawana, Yuichi KajiAbstract:PURPOSE To investigate the influence of pupil diameter on the relation between induced changes in ocular higher-order wavefront Aberrations and changes in contrast sensitivity by conventional laser in situ keratomileusis (LASIK) for myopia. METHODS In 215 eyes of 117 patients (age, 33.2 +/- 8.3 years) undergoing LASIK for myopia of -1.25 to -13.5 D (-5.28 +/- 2.55 D), ocular wavefront Aberrations and contrast sensitivity function were determined before and 1 month after surgery. Preoperative photopic pupil diameter was measured with a digital camera. Ocular higher-order Aberrations were measured for a 4-mm pupil with a Hartmann-Shack wavefront analyzer. The root-mean-square (RMS) of the third- and fourth-order Zernike coefficients was used to represent coma- and spherical-like Aberration, respectively. From the contrast-sensitivity data, the area under the log contrast sensitivity function (AULCSF) was calculated. RESULTS One hundred five eyes had a photopic pupil diameter of 4 mm or larger, and the remaining 110 had a photopic pupil diameter smaller than 4 mm. There were no statistically significant differences in the background clinical data between these two groups. In the eyes with a photopic pupil diameter of 4 mm or larger, the changes in third-order comalike Aberrations did not correlate with the changes in AULCSF (Pearson correlation coefficient, r = -0.037, P = 0.723) and 10% low-contrast visual acuity (r = 0.125, P = 0.224), but fourth-order spherical-like Aberrations correlated significantly with the changes in AULCSF (r = -0.229, P = 0.024) and 10% low-contrast visual acuity (r = 0.221, P = 0.038). In the eyes with photopic pupil size smaller than 4 mm, there were significant correlations between the changes in comalike Aberrations and the changes in AULCSF (r = -0.487, P < 0.001) and 10% low-contrast visual acuity (r = 0.310, P = 0.003), but spherical-like Aberrations showed no correlation with the changes in AULCSF (r = -0.078, P = 0.485) and 10% low-contrast visual acuity (r = 0.208, P = 0.158). CONCLUSIONS In eyes with larger photopic pupil diameter, increases in spherical-like Aberration dominantly affect contrast sensitivity, whereas in eyes with smaller pupil size, changes in coma-like Aberration exert greater influence on visual performance.
