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Biomedical subjects

B Falsini

Publications and source records attributed to B Falsini.

61 records · Page 4Linked to original sources
PubMed1988

Binocular interaction and steady-state visual evoked potentials. I. A study in normal subjects and in subjects with defective binocular vision.

A correlate of binocular-neuron activity was found in some properties of visual evoked potentials (VEPs), such as facilitation (defined as a binocular response greater than the sum of the monocular responses) and changes in latency (shortening of binocular VEP latency as compared to that of monocular VEPs). Monocular and binocular steady-state VEPs in response to phase-alternating gratings of different contrast and both spatial and temporal frequency were recorded in three normal subjects. Fourier analysis of the responses was performed to isolate the component at the reversal frequency. Binocular VEPs showed facilitation in the low-contrast range (3%-10%). Facilitation was highest for gratings that had spatial frequency of 0.6-2 cycles/degree (c/d), alternating at 16 reversals per second. Phase shortening was found across a parameter range larger than that at which amplitude facilitation occurred. These results suggest that both amplitude facilitation and phase shortening in binocular VEPs may provide an objective measure of binocular visual function in clinical ophthalmology.

Contrast Sensitivity↗
PubMed1987

Simultaneous macular and paramacular ERGs recorded by standard techniques.

A technique for the simultaneous recording of two small-field electroretinograms (ERGs), macular and paramacular, employing standard apparatuses for stimulation and analysis is described. The stimuli consisted of two adjacent checks (6 deg/side) obtained by masking the display of a commercially available TV pattern stimulator. The checks were square-wave-modulated in counterphase at 3.12 Hz. The subjects fixated the center of one of two checks. In one stimulus cycle, two ERGs could be distinguished: one from the macular area and the other from the adjacent area. The macular ERG is about twice as large as the paramacular. ERGs recorded by this technique can be considered focal since (i) they show a sharp fall-off in amplitude when the stimulus is displaced from the fovea, and (ii) they are no longer recordable when the stimulus is centered on the optic disk or on a large macular scar.

Electroretinography↗
PubMed1987

Pattern electroretinogram as a function of spatial frequency in ocular hypertension and early glaucoma.

Pattern electroretinograms (PERGs) in response to 8.3 Hz alternating gratings (16.6 rev/sec) of different spatial frequencies were recorded in normal subjects as well as in patients affected by early glaucoma and ocular hypertension. In normal subjects the PERG response is spatially tuned, with a maximum at about 1.5 cycles/deg and attenuation at higher and lower spatial frequencies. In all cases of early glaucoma and in the great majority of cases of ocular hypertension the PERG was reduced, as compared with that of normal subjects, mainly in the medium range of spatial frequencies (at which the PERG has its maximal amplitude).

Adult↗
PubMedDate not supplied

Simultaneously recorded macular and paramacular ERGs in diseases affecting the central retina.

Macular and paramacular ERGs in response to two alternating checks (6 deg/side) obtained from a standard TV stimulator were recorded in 34 normal subjects and in 54 patients affected by different macular diseases. Macular ERG amplitude and the amplitude ratio between macular and paramacular ERGs (M/P ratio) were measured. In normals, the intersubjects' variability of macular ERG was comparable to that reported using different stimulation/recording techniques. Macular ERG amplitude (but not the M/P ratio) was significantly affected by age. In patients, the mean amplitude of macular ERG and the mean M/P ratio were significantly lower than normal values. At least one of these two parameters was abnormal in 78.5% of eyes with maculopathy. Both macular ERG amplitude and M/P ratio were significantly correlated with visual acuity. The present results indicate that simultaneous macular and paramacular ERGs can be easily and reliably recorded in clinical routine to evaluate macular function. This technique appears to be particularly sensitive in hereditary macular diseases in which photoreceptors are primarily involved.

Adult↗
PubMedDate not supplied

Optical coherence tomography and focal electroretinogram evaluation of cystoid macular edema secondary to retinitis pigmentosa treated with intravitreal triamcinolone: case report.

PURPOSE: To assess macular structure and function by optical coherence tomography (OCT) and focal electroretinogram (FERG) before and after intravitreal triamcinolone acetonide (IVTA) administration for cystoid macular edema (CME) in a patient with retinitis pigmentosa (RP). METHODS: A 33-year-old man with RP and refractory bilateral macular edema was treated with IVTA in his left eye and evaluated with visual acuity, OCT, and FERG for 6 months. RESULTS. Compared to the fellow eye, after IVTA mean retinal thickness significantly decreased, while FERG amplitude and phase did not show significant changes at the end of follow-up. Visual acuity showed a significant tendency to improve. CONCLUSIONS: In this case report, IVTA improved macular anatomy and visual acuity; this result, however, was not associated with a similar electrophysiologic response.

Adult↗
PubMedDate not supplied

[Diet and management of degenerative diseases of the retina (retinitis pigmentosa)].

Considerable progress has been made in the understanding and management of degenerative diseases of the retina. The dietetic intervention has been favourably proposed in the most common forms of retinitis pigmentosa, a condition potentially leading to blindness. Vitamin A has been shown to be effective in delaying progression of the disease. In these patients such treatment is the only possible therapy, to date, and a lifetime generous supplementation of retinol is advisable, together with a vitamin A-rich diet and/or a dietary supplement (e.g. carrot flour) or pharmacologic supplement of vitamin A. Supply of vitamin A in doses up to 25000 IU (7500 igr/day), even for several years, has so far proved safe from risk of occurrence of liver disease. A possible effect on hypercholesterolemia related to a very prolonged treatment in predisposed individuals can be avoided by using a special diet, particularly enriched with beta-carotene. Guidelines for preparing a diet, specially formulated to provide an elevated weekly supply of vitamin and/or its precursor (equal to 15000 IU or 5000 microg of RE, retinol equivalent) and to control possible risk factors related to dietetic manipulation (supply of fat lower than 30% of total calories, variable levels of cholesterol and polyunsaturated fatty acids n-3, n-6) are presented. As long as resolutive therapy is lacking, dietetic intervention plays a primary role, although underestimated, in the management of the patients suffering from retinitis pigmentosa. The diet is specifically characterized by presence of food with a high content of carotenoids, substances with a favourable and additive effect.

Clinical Protocols↗