Association of ocular blood flow and contrast sensitivity in normal tension glaucoma

Graefe's Archive for Clinical and Experimental Ophthalmology - To investigate the relationship of ocular blood flow (via arteriovenous passage time, AVP) and contrast sensitivity (CS) in...     

Amplitude calculation in multifocal ERG: comparison of repeatability in 30 Hz flicker and first order kernel stimulation

BACKGROUND: In multifocal flicker stimulation, each step of the M-sequence consists of four consecutive flashes with a frequency of 30 Hz. The resulting amplitudes can be calculated by means of a discrete fourier transformation (DFT). With this method, amplitudes can be calculated without having to localise peaks and troughs and set cursors. The purpose of this study is to compare the re-test stability of this method to conventional mfERG stimulation. METHODS: We examined 27 healthy subjects using a RETI-scan device (Roland Consult, Wiesbaden). We used 61 hexagons within a 30 deg. visual field. We compared the classic first order kernel (FOK) stimulation with the multifocal 30 Hz Flicker (mfFlicker-ERG) stimulation. Repeatability was calculated using coefficients of variation. RESULTS: Both methods had coefficients of 15% for the sum P1-amplitude and the DFT results, respectively. The amplitudes calculated by flicker and DFT were approximately 25% smaller than the FOK amplitudes. CONCLUSIONS: This study showed no difference of re-test repeatability between the mfFlicker-ERG and the conventional first order kernel method. Since the mfFlicker-ERG method does not require a definition of peaks and troughs in order to calculate the amplitudes, we believe that a common source of error is eradicated, especially when dealing with distorted or atypical curves.     

A comparison of 8 and 16 frames gated SPECT imaging for determination of left ventricular volumes and ejection fraction: effects of gender and myocardial counts

The International Journal of Cardiovascular Imaging - In myocardial gated SPECT imaging each cardiac cycle is divided into 8 or 16 temporal frames and the cause of the difference between 8 and 16...     

A review of key challenges of electrospun scaffolds for tissue‐engineering applications

Tissue engineering holds great promise to develop functional constructs resembling the structural organization of native tissues to improve or replace biological functions, with the ultimate goal of avoiding organ transplantation. In tissue engineering, cells are often seeded into artificial structures capable of supporting three‐dimensional (3D) tissue formation. An optimal scaffold for tissue‐engineering applications should mimic the mechanical and functional properties of the extracellular matrix (ECM) of those tissues to be regenerated. Amongst the various scaffolding techniques, electrospinning is an outstanding one which is capable of producing non‐woven fibrous structures with dimensional constituents similar to those of ECM fibres. In recent years, electrospinning has gained widespread interest as a potential tissue‐engineering scaffolding technique and has been discussed in detail in many studies. So why this review? Apart from their clear advantages and extensive use, electrospun scaffolds encounter some practical limitations, such as scarce cell infiltration and inadequate mechanical strength for load‐bearing applications. A number of solutions have been offered by different research groups to overcome the above‐mentioned limitations. In this review, we provide an overview of the limitations of electrospinning as a tissue‐engineered scaffolding technique, with emphasis on possible resolutions of those issues. Copyright © 2015 John Wiley & Sons, Ltd.     

Vitrectomy with and without encircling band for pseudophakic retinal detachment with inferior breaks: VIPER Study Report No. 3

Graefe's Archive for Clinical and Experimental Ophthalmology - To test if an encircling band improves outcomes in vitrectomy for pseudophakic retinal detachment (PRD) with inferior or with...     

Improving the quality of multifocal visual evoked potential results by calculating multiple virtual channels

Purpose  

To introduce a method for improvement of multifocal VEP (mfVEP) recordings by prediction of waveforms at multiple positions on the surface of the skull.