Biomedical subjects

S Fonda

Publications and source records attributed to S Fonda.

4 recordsLinked to original sources

PubMed1990

Medical treatment of senile cataract: clinical investigation of bendazac-lysine using objective and subjective methods.

A modified Zeiss slit lamp coupled with a digital image-processing system was used to evaluate objectively changes in lens transparency over 1 year at 4-month intervals in 150 eyes of 92 patients affected by early senile cataract. A total of 59 patients were treated daily with 1.5 g bendazac-lysine, and 33 patients constituted the control group. At follow-up, visual acuity was also tested using Snellen letter charts at variable contrast to provide an additional parameter closer to traditional methods. Results indicate that the minimal angle of resolution at 10% contrast (MAR10) and the mean gray-level value of the lens image obtained by retroillumination (MLR) are sensitive to early changes in lens transparency. Using MAR10 as a parameter, the control group showed a significant, progressive worsening of the lens status over 12 months, whereas the treated group exhibited no significant changes. MRL indicated the same behaviour as MAR10, although lens damage was detected later in the control group. The results show that bendazac-lysine may delay the formation of lens opacities.

Aged↗

PubMed1987

Incremental binocular amplitude of the pattern visual evoked potential during the first five months of life: electrophysiological evidence of the development of binocularity.

The amplitude of the pattern visual evoked potential (VEP) of a binocular stimulus has been shown to be generally larger than the VEP obtained monocularly. There is evidence that this effect can be considered an electrophysiological index of fusion. To study how binocular vision develops in infancy we evaluated the incremental binocular amplitude (IBA) in three infants in a longitudinal investigation during the first five months of life. The stimuli were phase-alternating square-wave gratings with spatial and temporal parameters chosen to be appropriate for neonates. IBA was defined as the percentage increment of the largest binocular response compared with the monocular response. In the first two months of life IBA values were near zero, that is, no summation occurred. Between the second and third month IBA values rose markedly and after the third month its value was greater than 100%, demonstrating binocular facilitation. Thus in the first two months of life the eyes do not seem to cooperate as in adults. By the second and third month the binocular pattern VEP reflects an increasing binocular interaction. Other studies of the development of stereopsis have also found evidence of binocularity at similar ages.

Aging↗

PubMed1979

Pattern reversal visually evoked potentials in general anesthesia.

Various authors have tried to determine visual acuity both electrophysiologically (Sokol, 1976 and 1978; Marg et al., 1976; Maffei and Fiorentini, 1977) and with psychophysical methods (Teller et al., 1974; Banks and Salapatek, 1976; Atkinson et al., 1976) in awake children. Our experiments try to verify the possibility of assessing visual acuity in children under Ethrane anesthesia. We conclude that under Ethrane anesthesia VEPs produced by phase-alternating square-wave gratings do not allow a fine assessment of visual acuity. Gross indications of visual acuity can however be obtained.

Adolescent↗

PubMed1977

Relative photometric measurements of retinal circulation (dromofluorograms): a televison technique.

Television fluoroangiography is used in order to obtain fluorescein dilution curves (dromofluorograms [From the Greek word: epsilon rho omicron mu omicron, which means flowing. We coined this word because dilution curves do not afford a true measurement of the blood circulation, or simply of a dilution, but of the fluorescein transport in the circulation!] from single retinal vessels. An optical fiber conveys the light from a single retinal artery, vein, or any other retinal area on the video screen to a photomultiplier. After low-pass electronic filtration, the dilution curves are recorded on a strip-chart recorder. The measurements considered are all related to time: the time interval between initial instants of the arterial and venous curve; the time interval between maximum instants; the arterial and venous curve rising times. It is seen that (1) the method is sensitive enough to enable variations in the quantities in pathologic cases to be detected; (2) owing to the great variability from part to part of the vessels, it is important to specify where the retinal dromofluorogram has been recorded.

Collagen Diseases↗