Estimation of evoked potentials using total least squares Prony technique

PubMedID: 10367435The authors investigate the applicability of Prony modelling to the estimation of evoked potentials. Four types of total least squares (TLS) model are considered and their optimal parameters are defined based on ten visual averaged EPs. Simulations with various signal and noise characteristics show that the TLS-Prony estimation is superior to averaging for two of the models, namely the unconstrained and the stable models. Application of the TLS-Prony estimator as a post-processor to moderate averaging allows a reduction in the number of responses averaged, or equivalently of recording time, by a factor of two.The authors investigate the applicability of Prony modelling to the estimation of evoked potentials. Four types of total least squares (TLS) model are considered and their optimal parameters are defined based on ten visual averaged EPs. Simulations with various signal and noise characteristics show that the TLS-Prony estimation is superior to averaging for two of the models, namely the unconstrained and the stable models. Application of the TLS-Prony estimator as a post-processor to moderate averaging allows a reduction in the number of responses averaged, or equivalently of recording time, by a factor of two

Marked MVR knife for vitreoretinal surgery

WOS: 000182898700033PubMed ID: 1270762

Illuminated endochopper in the management of posteriorly dislocated lens nucleus

WOS: 000233184000018PubMed ID: 16246769We describe the use of an illuminated endochopper (a prototype instrument produced by DORC International) in the management of a posteriorly dislocated lens nucleus or lens particles. This instrument helps to divide the lens nucleus or its fragments into small pieces and thus reduces time and ultrasound energy

A novel suture technique in stellate corneal lacerations

WOS: 000170981100013PubMed ID: 11563791A novel suture technique for regular stellate corneal lacerations, called a star-shaped suture is described. The suturing begins from inside any of the wound tips in a clockwise direction. Suture placement proceeds in a counterclockwise direction by the adjacent wound limb, while the suture passes are all in clock-wise direction. Finally, a star-shaped suture is achieved with the knot self-buried in the corneal stroma at the initial entry site. This is a continuous suture, of which tractional forces direct to the center of the wound providing good apical apposition for stellate lacerations. This suture technique can be an alternative for the reconstruction of stellate corneal lacerations

Color Doppler imaging of choroidal circulation in patients with asymmetric age-related macular degeneration

WOS: 000181458300010PubMed ID: 12592053We aimed at evaluating the possible role of choroidal perfusion abnormalities in the development of choroidal neovascularisation (CNV) in patients with age-related macular degeneration (AMD). Twenty-six patients who had non-exudative AMD in the first eye and CNV secondary to AMD in the fellow eye were enrolled. Blood flow velocities, vessel pulsatilities and resistivities were measured from ophthalmic artery, nasal and temporal posterior ciliary arteries using colour Doppler imaging. Systolic and diastolic velocities were lower in eyes with CNV for all vessels, except for the systolic velocity of the nasal posterior ciliary artery (p >0.05). Pulsatility and resistivity indices were higher in eyes with CNV for all vessels. This difference was statistically significant for the resistivity index of the nasal and temporal posterior ciliary arteries (p = 0.032 and p = 0.021, respectively) and the pulsatility index of the nasal posterior ciliary artery (p = 0.035). We have shown that in patients with AMD choroidal blood flow is more impaired in the eyes with CNV than in the fellow eyes