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Biomedical subjects

F Lavenant

Publications and source records attributed to F Lavenant.

At least 37 records · Page 2Linked to original sources
PubMed1981

The muscle elongation test in functional esotropias. Statistical survey of 211 cases.

Study of the muscle elongation test in 211 patients with convergent squints who never have been operated on previously reveals that about 35% of cases display abnormal muscle stretching; 48 cases retain a lasting anesthetic angle in spite of a normal elongation test. Particularly significant correlations exist between a positive muscle elongation test and the degree of clinical oculogyric spasm, electro-oculographic motor impairments, squint deviation degrees, and age at strabismus onset. All these correlations prove that viscoelastic anomalies of the ocular muscles are secondary to supranuclear innervational impairments. In addition, both together have an asymmetrical degree on each eye in more than half the cases. The authors conclude that, in order to choose the correct surgical procedure, the results of the anesthetic and muscle elongation tests must be taken into account.

Child↗
PubMed1981

[Electro-oculographic study of vergence movements (author's transl)].

The study of vergence movements imperatively needs a recording method. Nowadays, in spite of its various drawbacks, electro-oculography is the most accurate method for clinical wants. The authors have studied the refixation vergence along a symmetrical inducing axis. With regard to both eyes in binocular and monocular fixations the analysis of a great lot of recordings in normal patients allows to reveal some phenomena unknown till now. In binocular fixation it is usual to notice a physiologic dyssynergy of vergence movements. The monocular fixations bear out evidence that Hering's Law doesn't apply to vergence movements. On the contrary they are submitted to a complete opto-motor dissociation, because the motor responses fully change according to the modalities of inducing visual inputs. In others respects, the analysis of all recordings proves that a vergence movement is made up with two synkinetic phases: a slow phase which was known for a long time thanks to physiological laboratory works; but also a fast phase having a saccadic feature. The fast vergence is related with a monocular visual attraction reflex and it is not bound only to the macular function.

Accommodation, Ocular↗
PubMed1981

[Atheromatous coronary artery disease: value of a study of calcification during assessment (author's transl)].

Correlations between calcifications and stenoses observed on coronarography were studied in 200 patients with coronary heart disease and calcifications in the coronary arteries. There was a very close relationship (p less than 0.0005) between the number of calcified and stenosed main coronary vessels. Calcification in the circumflex and right coronary vessels is a specific sign of stenosis. There was a high frequency of poor arterial beds distal to the stenoses when these were calcified. It is considered that the detection of coronary calcification by means of a brilliance amplifier constitutes one of the most effective non-invasive methods for assessing coronary artery disease.

Adult↗
PubMed1981

[Electro-oculographie study of vergence movements. II. Asymmetric vergence (author's transl)].

In relation to symmetrical vergence, a study of asymmetrical vergence reveals, in normal cases, particular kinetic phenomena of the most marked degree. In binocular fixation, Johannes Müller's phenomenon is noticed on the axial eye. It exhibits reflex competition between fast and slow vergence, and is always impaired in amblyopias. Monocular fixation with the centered open eye induces a pure and slow consensual vergence on the excentric occluded eye. The movement is mainly be accommodative in nature, and anomalies are shown to very frequent. Monocular fixation with the excentric open eye induces a relative vergence characterized by a fast version phase, limited and corrected by a slow vergence phase. Relative vergence is largely impaired in amblyopias, convergence deficiencies, functional squints and oculo-motor palsies. Generally, the different methods for investigating kinetic vergence patterns reveal a more or less physiological asymmetry in sensori motor potentialities of each eye. This asymmetry strongly increases in nearly all oculo-motor disorders.

Electrooculography↗
PubMedDate not supplied

[Differential photo-oculography of vertical and oblique movements].

Up to now EOG has been the only method used to record ocular movements in daily practice. However such a mean has various drawbacks and limits. It has two main gaps: firstly for vertical movements because the interference discharges related with palpebral movements and blinkings; on the other hand for oblique movements because the unequal transmission of EOG potential towards the orbital rim. The differential photo-oculography perfected by Charlier et Buquet has been fitted and now can be easily used in clinical conditions. With this optical method, it exists a direct relation between the gaze direction and video signals of the eye. The authors point out the reliability of its results not only for horizontal movements, but also for vertical and oblique movements. This method allows a relevant analysis of all kinetic parameters whatever the moving axis may be.

Eye Movements↗
PubMedDate not supplied

[Surgery of 6th nerve paralysis. 74 cases].

85% of abducens palsies recover spontaneously; then their surgical treatment has not to be hastened. However many non regressive cases are frequently observed. Whatever they may be, partial or complete, uni or bilateral, always they give a great functional handicap which warrants a surgical care. The analysis of 74 successive cases allows to reveal some rules concerning the operative plan. In that respect the electro-oculographic recording often provides many essential informations. The recovery of a normal oculo-motor balance is usual in monolateral paresis. In bilateral complete palsies, in spite of muscle transposition procedures, we can only expect to reduce torticollis and to restore the ocular alignment in primary position, but abduction remains always impaired or fully impeded.

Abducens Nerve↗