The Experts below are selected from a list of 69 Experts worldwide ranked by ideXlab platform

Cynthia J Roberts - One of the best experts on this subject based on the ideXlab platform.

  • long term follow up of ultrathin corneas after surface retreatment with phototherapeutic keratectomy
    Journal of Cataract and Refractive Surgery, 2005
    Co-Authors: Paolo Vinciguerra, Fabrizio I Camesasca, Maria Ingrid Torres Munoz, Fabio Grizzi, Cynthia J Roberts
    Abstract:

    Purpose To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 μm and cornea-related vision problems. Setting Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano−Milan, Italy. Methods This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 μm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 ± 0.09 (SD) with −2.53 ± 2.34 diopters (D), and the mean pachymetry was 390 ± 38 μm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, Optical Refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. Results At 1 year, the mean BSCVA was 0.6 ± 0.72 with −2.15 ± 1.67 D and the mean pachymetry, 341 ± 40 μm. At 5 years, the mean BSCVA was 0.7 ± 0.15 with −2.33 ± 1.12 D and the mean pachymetry, 339 ± 48 μm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of Refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. Conclusions After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the Optical Refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.

  • long term follow up of ultrathin corneas after surface retreatment with phototherapeutic keratectomy
    Journal of Cataract and Refractive Surgery, 2005
    Co-Authors: Paolo Vinciguerra, Fabrizio I Camesasca, Maria Ingrid Torres Munoz, Fabio Grizzi, Cynthia J Roberts
    Abstract:

    Purpose To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 μm and cornea-related vision problems. Setting Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano−Milan, Italy. Methods This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 μm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 ± 0.09 (SD) with −2.53 ± 2.34 diopters (D), and the mean pachymetry was 390 ± 38 μm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, Optical Refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. Results At 1 year, the mean BSCVA was 0.6 ± 0.72 with −2.15 ± 1.67 D and the mean pachymetry, 341 ± 40 μm. At 5 years, the mean BSCVA was 0.7 ± 0.15 with −2.33 ± 1.12 D and the mean pachymetry, 339 ± 48 μm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of Refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. Conclusions After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the Optical Refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.

Paolo Vinciguerra - One of the best experts on this subject based on the ideXlab platform.

  • long term follow up of ultrathin corneas after surface retreatment with phototherapeutic keratectomy
    Journal of Cataract and Refractive Surgery, 2005
    Co-Authors: Paolo Vinciguerra, Fabrizio I Camesasca, Maria Ingrid Torres Munoz, Fabio Grizzi, Cynthia J Roberts
    Abstract:

    Purpose To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 μm and cornea-related vision problems. Setting Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano−Milan, Italy. Methods This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 μm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 ± 0.09 (SD) with −2.53 ± 2.34 diopters (D), and the mean pachymetry was 390 ± 38 μm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, Optical Refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. Results At 1 year, the mean BSCVA was 0.6 ± 0.72 with −2.15 ± 1.67 D and the mean pachymetry, 341 ± 40 μm. At 5 years, the mean BSCVA was 0.7 ± 0.15 with −2.33 ± 1.12 D and the mean pachymetry, 339 ± 48 μm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of Refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. Conclusions After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the Optical Refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.

  • long term follow up of ultrathin corneas after surface retreatment with phototherapeutic keratectomy
    Journal of Cataract and Refractive Surgery, 2005
    Co-Authors: Paolo Vinciguerra, Fabrizio I Camesasca, Maria Ingrid Torres Munoz, Fabio Grizzi, Cynthia J Roberts
    Abstract:

    Purpose To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 μm and cornea-related vision problems. Setting Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano−Milan, Italy. Methods This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 μm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 ± 0.09 (SD) with −2.53 ± 2.34 diopters (D), and the mean pachymetry was 390 ± 38 μm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, Optical Refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. Results At 1 year, the mean BSCVA was 0.6 ± 0.72 with −2.15 ± 1.67 D and the mean pachymetry, 341 ± 40 μm. At 5 years, the mean BSCVA was 0.7 ± 0.15 with −2.33 ± 1.12 D and the mean pachymetry, 339 ± 48 μm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of Refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. Conclusions After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the Optical Refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.

Johannes Courtial - One of the best experts on this subject based on the ideXlab platform.

  • experimental demonstration of ray Optical Refraction with confocal lenslet arrays
    Optics Letters, 2010
    Co-Authors: Johannes Courtial, Blair C Kirkpatrick, Eric Logean, Toralf Scharf
    Abstract:

    We observe imaging through windows comprising pairs of confocal lenslet arrays that have different focal lengths but that are otherwise identical. Image space is stretched in the longitudinal direction only. Such windows are examples of METATOYs, Optical components that can change light-ray direction in ways that appear wave-Optically forbidden.

  • ray Optical Refraction with confocal lenslet arrays
    New Journal of Physics, 2008
    Co-Authors: Johannes Courtial
    Abstract:

    Two parallel lenslet arrays with focal lengths f1 and f2 that share a common focal plane (that is, which are separated by a distance f1+f2) can refract transmitted light rays according to Snell's law, but with the 'sin's replaced with 'tan's. This is the case for a limited range of input angles and other conditions. Such confocal lenslet arrays can therefore simulate the interface between Optical media with different refractive indices, n1 and n2, whereby the ratio η=-f2/f1 plays the role of the refractive-index ratio n2/n1. Suitable choices of focal lengths enable positive and negative Refraction. In contrast to Snell's law, which leads to nontrivial geometric imaging by a planar refractive-index interface only for the special case of n1=±n2, the modified Refraction law leads to geometric imaging by planar confocal lenslet arrays for any value of η. We illustrate some of the properties of confocal lenslet arrays with images rendered using ray-tracing software.

Maria Ingrid Torres Munoz - One of the best experts on this subject based on the ideXlab platform.

  • long term follow up of ultrathin corneas after surface retreatment with phototherapeutic keratectomy
    Journal of Cataract and Refractive Surgery, 2005
    Co-Authors: Paolo Vinciguerra, Fabrizio I Camesasca, Maria Ingrid Torres Munoz, Fabio Grizzi, Cynthia J Roberts
    Abstract:

    Purpose To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 μm and cornea-related vision problems. Setting Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano−Milan, Italy. Methods This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 μm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 ± 0.09 (SD) with −2.53 ± 2.34 diopters (D), and the mean pachymetry was 390 ± 38 μm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, Optical Refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. Results At 1 year, the mean BSCVA was 0.6 ± 0.72 with −2.15 ± 1.67 D and the mean pachymetry, 341 ± 40 μm. At 5 years, the mean BSCVA was 0.7 ± 0.15 with −2.33 ± 1.12 D and the mean pachymetry, 339 ± 48 μm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of Refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. Conclusions After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the Optical Refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.

  • long term follow up of ultrathin corneas after surface retreatment with phototherapeutic keratectomy
    Journal of Cataract and Refractive Surgery, 2005
    Co-Authors: Paolo Vinciguerra, Fabrizio I Camesasca, Maria Ingrid Torres Munoz, Fabio Grizzi, Cynthia J Roberts
    Abstract:

    Purpose To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 μm and cornea-related vision problems. Setting Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano−Milan, Italy. Methods This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 μm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 ± 0.09 (SD) with −2.53 ± 2.34 diopters (D), and the mean pachymetry was 390 ± 38 μm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, Optical Refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. Results At 1 year, the mean BSCVA was 0.6 ± 0.72 with −2.15 ± 1.67 D and the mean pachymetry, 341 ± 40 μm. At 5 years, the mean BSCVA was 0.7 ± 0.15 with −2.33 ± 1.12 D and the mean pachymetry, 339 ± 48 μm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of Refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. Conclusions After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the Optical Refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.

Fabio Grizzi - One of the best experts on this subject based on the ideXlab platform.

  • long term follow up of ultrathin corneas after surface retreatment with phototherapeutic keratectomy
    Journal of Cataract and Refractive Surgery, 2005
    Co-Authors: Paolo Vinciguerra, Fabrizio I Camesasca, Maria Ingrid Torres Munoz, Fabio Grizzi, Cynthia J Roberts
    Abstract:

    Purpose To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 μm and cornea-related vision problems. Setting Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano−Milan, Italy. Methods This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 μm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 ± 0.09 (SD) with −2.53 ± 2.34 diopters (D), and the mean pachymetry was 390 ± 38 μm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, Optical Refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. Results At 1 year, the mean BSCVA was 0.6 ± 0.72 with −2.15 ± 1.67 D and the mean pachymetry, 341 ± 40 μm. At 5 years, the mean BSCVA was 0.7 ± 0.15 with −2.33 ± 1.12 D and the mean pachymetry, 339 ± 48 μm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of Refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. Conclusions After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the Optical Refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.

  • long term follow up of ultrathin corneas after surface retreatment with phototherapeutic keratectomy
    Journal of Cataract and Refractive Surgery, 2005
    Co-Authors: Paolo Vinciguerra, Fabrizio I Camesasca, Maria Ingrid Torres Munoz, Fabio Grizzi, Cynthia J Roberts
    Abstract:

    Purpose To evaluate visual acuity and long-term stability after phototherapeutic keratectomy (PTK) in patients with corneal thickness less than 400 μm and cornea-related vision problems. Setting Department of Ophthalmology, Istituto Clinico Humanitas, Rozzano−Milan, Italy. Methods This retrospective study comprised 48 eyes that had PTK for complications after photorefractive keratectomy that removed more than 200 μm of tissue. Phototherapeutic keratectomy was performed with the Nidek EC-5000 excimer laser with 10 Hz frequency, intraoperative topography, and masking fluid over an ablation diameter of 10.0 mm. The follow-up was 5 years. The mean preoperative best spectacle-corrected visual acuity (BSCVA) was 0.2 ± 0.09 (SD) with −2.53 ± 2.34 diopters (D), and the mean pachymetry was 390 ± 38 μm. The efficacy parameters were pachymetry and visual acuity at 1 year and the stability parameters, Optical Refraction, corneal curvature (calculated as the mean curvature over the entire 3.0 mm and 5.0 mm central zones), and pachymetry from 1 to 5 years. Results At 1 year, the mean BSCVA was 0.6 ± 0.72 with −2.15 ± 1.67 D and the mean pachymetry, 341 ± 40 μm. At 5 years, the mean BSCVA was 0.7 ± 0.15 with −2.33 ± 1.12 D and the mean pachymetry, 339 ± 48 μm. In all patients, there was an improvement of 4 or more Snellen lines. Statistical evaluation of Refraction and corneal curvature values at 1 and 5 years indicated no statistically significant differences. Conclusions After PTK in eyes with ultrathin corneas, there was significant improvement in BSCVA and long-term stability of the Optical Refraction, corneal curvature, and pachymetry. In selected cases, 10.0 mm ablation zone PTK may be an alternative to penetrating keratoplasty, offering long-term corneal stability.