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Biomedical subjects

C Corbe

Publications and source records attributed to C Corbe.

At least 19 recordsLinked to original sources
PubMed1995

[Contrast sensitivity in navigating seamen].

UNLABELLED: Visual acuity measurement is the ophthalmological test used for determining the majority of professional aptitude thresholds. In the case of ship pilotage however, the necessity to detect physical information of size and variable contrast can only be partly assessed by this parameter. AIMS OF THE STUDY: A test considered to be more ergonomic for the visual capacity evaluation of seamen, and for the early diagnosis of ocular abnormalities, was evaluated. METHOD: At the time of their statutory aptitude visit, 159 professional seamen underwent a test for morphoscopic sense at variable contrast and luminance, gradual. RESULTS: Twenty-seven ametropias of -0.75 to +3.00 diopters, 2 hypertensive retinopathies and 2 optical neuropathies were detected. Despite their low visual acuity, the myopic subjects were able to preserve normal visual efficiency in low contrast, without correction. Inversely, in spite of the correction, a deficiency was noted at medium and low contrasts, with a special increase at low luminance. The 7 patients operated on for radial keratotomy, although their visual acuity reached 10/10, presented a morphoscopic discrimination deficiency at low and medium contrasts. CONCLUSION: The test used in this study is designed for morphoscopic discrimination testing in which contrast and luminance are variable. This determination of luminance contrast sensibility seems to be an informative, sensitive and reliable means of detecting uncorrected ametropia and diverse organic pathologies at their inset.

Adolescent↗
PubMed1993

Aircrew fitness decisions and advances in refractive surgery techniques.

Refractive surgery is a well mastered technique for the correction of ametropia. The results in terms of recovery of visual acuity are generally very satisfactory. However, when patients are applicants for pilot training it is necessary to consider the structural effects of the operation and its repercussions on the visual function. Since 1981, we have examined 273 eyes of subjects applying to flight crew. The alterations, in the corneal structure, in the sensitivity to contrasts, and in the resistance to glare have dampened the former enthusiasm of the operated. We have evaluated the functional and clinical consequences of each individual case as well as the administrative decisions made concerning these applicants. The outcome is that on average one of three applicants obtained a dispensation within a time limit ranging from 1 to 5 years after surgery, according to the field applied for.

Adolescent↗
PubMed1992

Effect of a dopaminergic agonist, piribedil (Trivastal 50 mg LP), on visual and spatial integration in elderly subjects.

Dopamine acts as a neuromodulator in the retina. Dopaminergic deficiency of any origin, as observed in elderly subjects, is associated with altered visual performances, and more specifically with altered perception of contrasts. The goal of this study was to compare contrast vision in elderly subjects and young subjects (first phase, n = 20), then to compare this function in elderly subjects before and after 3 months of treatment with a dopaminergic agonist, piribedil (Trivastal 50 mg LP), administered once daily (second phase, n = 20). The perception of contrast was analysed using a test measuring sensitivity to colour contrast yielding threshold values for sensitivity to contrast in eight spatial frequencies and three colours (red, green, blue) and in two directions (horizontal and vertical). The results of the first phase of the study demonstrated that elderly subjects showed a decrease in contrast perception in comparison with young subjects, primarily in the high frequency range, and over the full range of stimulation for direction and colour. In the second phase, elderly subjects, in comparison with young subjects, showed altered visual contrast, again in the high frequency range, but also in the low frequency range for horizontal simulation with red and blue. After 3 months of treatment with piribedil the mean contrast sensitivity threshold, over the entire frequency range, had significantly increased (P less than 0.05) for all stimulations, apart for red in the vertical direction. These results underline the value of treatment with a dopaminergic agonist, piribedil in visual disturbances in patients with dopaminergic deficiency (Parkinson patients or elderly subjects).

Aged↗
PubMed1990

[Visual handicap, autonomy and third party compensation. Evaluation trials].

Nowadays visual disability compensation, as for other disabilities, is mainly contingent on the patient's obtaining an allowance for a third party, but this is increasingly related to the concept of autonomy in the main activities of everyday life. This concept cannot be applied to visual handicaps. A special allowance, however, which need not be identical to that of third party compensation but would cover the poor-sighted currently in groups 2 and 3, whatever the extent of their handicap, may be the right solution for the Authorities to adopt, due to the specific nature of the visual handicap.

Activities of Daily Living↗
PubMed1989

[Aids for low vision--strategic approach].

There are currently methods to rehabilitate the remaining visual function of visually impaired people. Treatment stages and tests are based on classical physiology of vision and still remain strictly experimental. Recent investigations showed that the visual system, as a whole, operates as a space frequency analyzer. There are reception to each spatial frequency. They have to be assessed with accuracy before any rehabilitation attempting to develop channels which are still functional by elective stimulation. This stimulation must have a maximum determined energetic efficiency. The study of the Fourier spectrum on two different images demonstrates this possibility and starts opening the way for specific research.

Contrast Sensitivity↗
PubMed1989

[A case of MEWDS. "The multiple evanescent white-dot syndrome"].

A young white man developed acute bilateral visual loss with no previous general illness. Ophthalmoscopic examination showed multiple small yellow-white lesions scattered throughout the posterior poles and mild periphery fundus. There was also fine granularity of two foveal areas and one optic disc margin was blurred. Fluorescein angiography showed early hyperfluorescence of the lesions and late staining of the retinal pigment epithelium. Electrophysiologic abnormalities were transient, asymmetric, more marked in photopic than in scotopic. The origin could be in retinal bipolar cells. These lesions regressed, with return of normal visual function within several weeks. These clinical findings are different from others acute inflammatory diseases primarily involving retinal pigment epithelium and photoreceptors. This aspect is usually described as "multiple evanescent white dot syndrome". The etiology of this syndrome remains unknown with no evidence of systemic disease. A history of flulike illness is rare.

Adult↗
PubMed1988

[A glaucoma follow-up of 1500 persons over 20 years].

The parameters of glaucoma risk have been compiled and computer processed on 1,571 patients during 20 years at the C.P.E.M.P.N. (Medical Evaluation Center for the Aeronautic Staff) of Paris. The goal of this study is to follow in real time the évolution of these parameters and to determine their physiological variations across time in terms of age and professional categories. An average intra-ocular pressure of 15.1 mmHg as well as hypertonia and glaucoma percentages respectively of 3.88% and 0.6% have been recorded in this study. These results were below the results of other previous surveys due to the greater age range of our study the youngest being 15 years old. There was no significant difference among pilots and non pilots. The optic disc examination was not decisive for diagnostic screening.

Adolescent↗
PubMed1986

[Clinical value of the colored contrast sensitivity test. Preliminary note].

Evaluation of color contrast sensitivity is a new test for the assessment of visual capacity and especially of light stimulation transfer along the optic pathway. The color technique yields more accurate results. It is combined with previously existing functional examinations and allows very early detection of subclinical signs of starting pathological processes.

Color Perception Tests↗