Transient cardiac ischaemia and abnormal variations in systemic blood pressure in unselected primary open angle glaucoma patients

To investigate the relationship between the occurrence of transient cardiac ischaemic episodes and variations in the ambulatory 24-h blood pressure and heart rate measurements in a group of unselected glaucoma patients.

Transient response in high-resolution Brillouin-based distributed sensing using probe pulses shorter than the acoustic relaxation time

We perform numerical simulations on a model describing a Brillouin-based temperature and strain sensor, testing its response when it is probed with relatively short pulses. Experimental results were recently published [e.g., Opt. Lett. 24, 510 (1999)] that showed a broadening of the Brillouin loss curve when the probe pulse duration is reduced, followed by a sudden and rather surprising reduction of the linewidth when the pulse duration gets shorter than the acoustic relaxation time. Our study reveals the processes responsible for this behavior. We give a clear physical insight into the problem, allowing us to define the best experimental conditions required for one to take the advantage of this effect.

Studies on the luminance-related characteristics of the transient pattern reversal electroretinogram

The electroretinogram evoked by reversal pattern stimulation (rPERG) is known to contain both pattern contrast and luminance related components. The retinal mechanisms of the transient rPERGs subserving these functional characteristics are the main concern in the present studies. Considerable attention has been paid to the luminance-related characteristics of the response. The transient PERGs were found to consist of two subsequent processes using low frequency attenuation analysis. The processes overlapped and the individual difference in each process timings formed the major cause for the variations of the negative potential waveform of the transient rPERGs. Attention has been paid to those having ‘notch’ type of variation. Under different contrast levels, the amplitudes of the positive and negative potentials were linearly increased with higher contrast level and the negative potential showed a higher sensitivity to contrast changes and higher contrast gain. Under lower contrast levels, the decreased amplitudes made the difference in the timing course of the positive and negative processes evident, interpreting the appearance of the notch in some cases. Visual adaptation conditions for recording the transient rPERG were discussed. Another effort was to study the large variation of the transient rPERGs (especially the positive potential, P50) in the elderly who’s distant and near visual acuity were normal. It was found that reduction of retinal illumination contributed mostly to the P50 amplitude loss and contrast loss mostly to the negative potential (N95) amplitude loss. Senile miosis was thought to have little effect on the reduction of the retinal illumination, while the changes in the optics of the eye was probably the major cause for it, which interpreted the larger individual variation of the P50 amplitude of the elderly PERGs. Convex defocus affected the transient rPERGs more effectively than concave lenses, especially the N95 amplitude in the elderly. The disability of accommodation and the type and the degree of subjects’ ametropia should be taken into consideration when the elderly rPERGs were analysed.

Nearwork-induced transient myopia (NITM) in anisometropia

Objective: To assess the magnitude of nearwork-induced transient myopia (NITM) under binocular viewing conditions separately in each eye of individuals with mild to moderate anisometropia to determine the relationship between NITM and their interocular refractive error. Methods: Forty-three children and young adults with anisometropia [cycloplegic spherical equivalent (SE) difference >1.00 D] were tested (ages 9-28 years). NITM was measured with binocular viewing separately in each eye after binocularly performing a sustained near task (5 D) for 5 min incorporating a cognitive demand using an open-field, infrared autorefractor (Grand-Seiko, WAM-5500). Data were averaged over 10 s bins for 3 min in each eye. Initial NITM, its decay time (DT), and its decay area (DA) were determined. A-scan ultrasound ocular biometry was also performed to determine the axial length of each eye. Results: The more myopic eye exhibited increased initial NITM, DT, and DA as compared to the less myopic eye (0.21 ± 0.16 D vs 0.15 ± 0.13 D, p = 0.026; 108.4 ± 64.3 secs vs 87.0 ± 65.2 secs, p = 0.04; and 17.6 ± 18.7 D*secs vs 12.3 ± 15.7 D*secs, p = 0.064), respectively. The difference in DA and the difference in SE between the more versus less myopic eye were significantly correlated (r = 0.31, p = 0.044). Furthermore, 63% (27/43), 56% (24/43), and 70% (30/43) of the more myopic eyes exhibited increased initial NITM, longer DT, and larger DA, respectively, than found in the less myopic eye. Conclusions: In approximately two-thirds of the anisometropic individuals, the initial NITM and its decay area were significantly increased in the more myopic eye as compared to the less myopic eye. NITM may play an important role in the development of interocular differences in myopia, although a causal relationship is yet to be established. Furthermore, the findings have potentially important implications regarding accommodative control and interocular accommodative responsitivity in anisometropia, in particular for anisomyopia. © 2013 The College of Optometrists.

Drug-induced bilateral transient myopia with the sulphonamide sulphasalazine

Whereas there are numerous reported ocular side effects from systemic sulpha medication, most are rare and reversible, with myopia being the most common reaction observed. A case report is presented of sudden bilateral onset of -1.0 DS of myopia (from -3.0 to -4.0 DS) in a young adult female following the addition of a sulphonamide (sulphasalazine) to oral non-steroidal anti-inflammatory treatment (meloxicam) for rheumatoid arthritis. The myopia regressed to -3.50 DS after 2 weeks when all medication was withdrawn and stabilised at this level when subsequent treatment was resumed after 8 weeks with the non-steroidal anti-inflammatory drug celecoxib. The case indicates that account needs to be taken of the possibility that relatively modest myopic shifts encountered in young adult contact lens wearers may be associated with concomitant systemic medication. © 2003 The College of Optometrists.

Transient response in high-resolution Brillouin-based distributed sensing using probe pulses shorter than the acoustic relaxation time

We perform numerical simulations on a model describing a Brillouin-based temperature and strain sensor, testing its response when it is probed with relatively short pulses. Experimental results were recently published [e.g., Opt. Lett. 24, 510 (1999)] that showed a broadening of the Brillouin loss curve when the probe pulse duration is reduced, followed by a sudden and rather surprising reduction of the linewidth when the pulse duration gets shorter than the acoustic relaxation time. Our study reveals the processes responsible for this behavior. We give a clear physical insight into the problem, allowing us to define the best experimental conditions required for one to take the advantage of this effect.

Transient reconfigurable subangstrom-precise photonic circuits at the optical fiber surface

Transient fully reconfigurable photonic circuits can be introduced at the optical fiber surface with subangstrom precision. A building block of these circuits - a 0.7Å-precise nano-bottle resonator - is experimentally created by local heating, translated, and annihilated.