Time filter

Source Type

Herndon, VA, United States

Morimoto T.,Applied Visual Sciences
International Review of Neurobiology | Year: 2012

Neurons of the central nervous system (CNS) of adult mammals can be damaged in a variety of ways. Most neurons rapidly die after injury. Even if the injured CNS neurons do not die in a short time, the neurons eventually die because they are not able to regenerate their axons to reconnect with their normal targets. In addition, neurons are normally not replaced. Therefore, much work has been directed toward understanding of the molecular regulation of the CNS degeneration following injury, and different experimental strategies are being used to try to protect the damaged neurons. Following axonal lesion, the neurons not only need to survive but also to reconnect to be functionally relevant, and efforts are directed toward not only survival but also axonal regeneration and proper rewiring of injured neurons. Recent experimental data suggest that electrical activity, endogenous or exogenous, can enhance neuronal survival and regeneration in vitro and in vivo. This chapter reviews the evidence that have been obtained on the role of neuronal electrical activity on neuroprotection. We will develop perspectives toward neuroprotection and regeneration of adult lesioned CNS neurons based on electrical activity-dependent cell survival that may be applicable to various diseases of the CNS. © 2012 Elsevier Inc. Source

Polizzi S.,University of Florence | Fujikado T.,Applied Visual Sciences
Optometry and Vision Science | Year: 2016

Purpose To report a case of transient loss of accommodation after laser photocoagulation for peripheral retinal tear. Loss of accommodation is one of the lesser known and less common complications of peripheral retinal laser photocoagulation. In fact, only a few works concerning this issue have been published so far. Deficit of accommodation has been described only after extensive laser treatment of the peripheral retina. To the best of our knowledge, this is the first case that reports this complication after treatment limited to a small retinal area. We discuss the possible pathogenetic mechanism of this phenomenon. Case Report A 25-year-old healthy myopic woman came to the eye clinic for flashes and floaters in her right eye. Fundus evaluation revealed a small horseshoe retinal tear at the 6 o'clock position. She was treated with prophylactic retinal laser barrage in the right eye. Twelve days later, she returned to our Retinal Clinic because of difficulty with near vision. The problem started soon after the laser procedure. On examination, her distance visual acuity was 20/20 wearing her glasses. The patient could read J1+ at 33 cm with the left eye and required a +3.00D addition over her corrective lens to read J1+ with the right eye. The accommodative disturbance resolved itself spontaneously and gradually within 3 months of laser treatment. Conclusions We believe that transient loss of accommodation, although rare, should be included during pretreatment discussion with young patients regarding the possible side effects of laser photocoagulation, even if this is limited to a small area of the peripheral retina. © 2015 American Academy of Optometry. Source

Koh S.,Osaka University | Maeda N.,Osaka University | Nakagawa T.,Osaka University | Higashiura R.,Osaka University | And 5 more authors.
American Journal of Ophthalmology | Year: 2012

Purpose: To investigate the corneal higher-order aberrations (HOAs) of the anterior and posterior corneal surfaces in eyes that underwent penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), and Descemet stripping automated endothelial keratoplasty (DSAEK). Design: Retrospective, case-control study. Methods: study population: Twenty-four eyes underwent PK, 28 eyes underwent DALK, and 19 eyes underwent DSAEK; 29 normal eyes served as controls. observation procedures: The anterior and posterior corneal heights and pachymetric data were obtained with a Scheimpflug-based corneal topographer. Corneal HOAs for 4-mm pupils were calculated from the height data and were expanded with normalized Zernike polynomials. The HOAs resulting from the anterior and posterior corneal surfaces were compared among the procedures. main outcome measures: Anterior and posterior corneal HOAs (root mean square). Results: Control eyes had significantly lower total HOAs and Zernike vector terms of the anterior and posterior surfaces than the other groups, except for spherical aberration. The mean anterior corneal surface total HOAs in the PK, DALK, DSAEK, and control groups were 1.38 ± 0.67 μm, 1.19 ± 0.57 μm, 0.61 ± 0.33 μm, and 0.21 ± 0.07 μm, respectively. The anterior corneal HOAs in the DSAEK group were significantly less than those in the PK group (P <.001) and DALK group (P <.001). The mean posterior corneal surface total HOAs were, respectively, 0.20 ± 0.09 μm, 0.24 ± 0.11 μm, 0.27 ± 0.15 μm, and 0.07 ± 0.02 μm. There were no significant differences in the posterior corneal HOAs among the treatment groups. Conclusions: Because the refractive indices between the anterior and the posterior surfaces differed greatly, eyes that undergo DSAEK have lower anterior corneal HOAs compared with PK or DALK eyes. However, the anterior and posterior corneal HOAs in DSAEK eyes still were greater than those in control eyes. © 2012 Elsevier Inc. All rights reserved. Source

Fujikado T.,Applied Visual Sciences
Clinical Ophthalmology | Year: 2014

Methods: Three types of IOL holders were prepared. The first was without decentration or tilt, the second had a decentration of 0.5 mm, and the third had a tilt of 5.0°. One spherical IOL and three aspherical IOLs, each with a power of +20 D, were set in the holders and their optical properties (wave front aberration, defocused modulation transfer function, defocused point spread function, and Landolt ring simulations) were compared.Results: Coma aberrations generated by misaligned IOLs were related to the spherical aberration corrective power of the IOLs. Landolt ring simulations show that the depth of focus increased as spherical aberration increased and that the retinal image quality was degraded by increases in coma aberration.Conclusion: Coma aberration was generated by IOLs with a large degree of spherical aberration correction, leading to reduced retinal image quality when the IOL was misaligned. This suggests that, in a clinical setting, the quality of vision might be improved by reducing the degree of coma aberration using IOLs that retain, or minimally correct, spherical aberration.Purpose: To examine the effect of misalignment (decentration and tilt) of intraocular lenses (IOLs) on retinal image quality using a water-immersed model eye with corneal spherical aberration adjusted to the values found in normal human eyes (spherical aberration 0.25 μm; pupil diameter 6 mm). © 2014 Fujikado and Saika. Source

Morimoto T.,Osaka University | Miyoshi T.,Osaka University | Sawai H.,Osaka University | Fujikado T.,Applied Visual Sciences
Experimental Eye Research | Year: 2010

We previously showed that transcorneal electrical stimulation (TES) promoted the survival of axotomized retinal ganglion cells (RGCs) of rats. However the relationship between the parameters of TES and the neuroprotective effect of TES on axotomized RGCs was unclear. In the present study, we determined whether the neuroprotective effect of TES is affected by the parameters of TES. Adult male Wistar rats received TES just after transection of the left optic nerve (ON). The pulse duration, current intensity, frequency, waveform, and numbers of sessions of the TES were changed systematically. The alterations of the retina were examined histologically seven days or fourteen days after the ON transection. The optimal neuroprotective parameters were pulse duration of 1 and 2 ms/phase (P < 0.001, each), current intensity of 100 and 200 μA (P < 0.05, each), and stimulation frequency of 1, 5, and 20 Hz (P < 0.001, respectively). More than 30 min of TES was necessary to have a neuroprotective effect (P < 0.001). Symmetric pulses without an inter-pulse interval were most effective (P < 0.001). Repeated TES was more neuroprotective than a single TES at 14 days after ON transection (P < 0.001). Our results indicate that there is a range of optimal neuroprotective parameters of TES for axotomized RGCs of rats. These values will provide a guideline for the use of TES in patients with different retinal and optic nerve diseases. © 2009 Elsevier Ltd. Source

Discover hidden collaborations