Selective Reflection Spectroscopy at the Interface between a Calcium Fluoride Window and Cs Vapour

A special vapour cell has been built, that allows the measurement of the atom-surface van der Waals interaction exerted by a CaF2 window at the interface with Cs vapour. Mechanical and thermal fragility of fluoride windows make common designs of vapour cells unpractical, so that we have developed an all-sapphire sealed cell with an internal CaF2 window. Although impurities were accidentally introduced when filling-up the prototype cell, leading to a line-broadening and shift, the selective reflection spectrum on the Cs D1 line (894 nm) makes apparent the weak van der Waals surface interaction. The uncertainties introduced by the effects of these impurities in the van der Waals measurement are nearly eliminated when comparing the selective reflection signal at the CaF2 interface of interest, and at a sapphire window of the same cell. The ratio of the interaction respectively exerted by a sapphire interface and a CaF2 interface is found to be 0.55 $\pm$ 0.25, in good agreement with the theoretical evaluation of ~0.67.Comment: soumis \`a Appl Phys B MS 4734

Azokh caves excavations 2002-2006: Middle-Upper palaeolithic transition in Nagorno-Karabagh

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

NORMATIVE DATABASES FOR OPTICAL COHERENCE TOMOGRAPHY (LITERATURE REVIEW)

An analysis of the quantitative results of optical coherence tomography (OCT) includes a comparison with normative databases. In their structure, the existing databases of the OCT devices do not have major differences. Most of them are diversified (include persons of different ethnic origin) and have significant limitations on age and refractive error (the length of the eye), what adversely affects the diagnostic power of the OCT, particularly in individuals with extreme values of these parameters. Databases are proposed or are in development for children and people older than 80 years, but such databases are not included in the OCT software yet. A proper evaluation of the results in patients with highdegree refractive errors is only possible using specialized databases. Long Axial Length Normative Database for Nidek RS series devices can serve as an example, but it is limited to the representatives of the Asian race. It is very important to develop similar databases for all ethnic groups of the population (or diversified) for this and other OCT devices. The methods were developed for correction of the magnification effect of the optical system of the eyes with refractive errors. These methods have limited value and could be applied to few parameters measured by OCT

A COMPARATIVE STUDY OF VICRYL SUTURES 6-0 AND 7-0 STRENGTH CAPACITY FOR STRABISMUS SURGERY

Purpose. A comparative study of vicryl sutures 6-0 and 7-0 durability.Material and methods. The study was conducted in 20 enucleated pig eyes, divided into 2 groups (10 eyes each). We used vicryl suture 7-0 in the main group and 6-0 for control eyes. After surgical recession of the medial rectus we used the INSTRON 3382 dual column floor model testing system to access extensibility, increasing suture strain. At the moment of the first suture rupture we measured strain and muscle elongation.Results. On average, vicryl suture 7-0 endured half the strain and muscle elongation before the rupture than vicryl 6-0. But this kind of stress reduction is not critical for the overall result, because to tear a muscle sutured with a fine thread, extraocular muscles would still need 4 times the force they naturally possess.Conclusion. Fine vicryl 7-0 thread possesses the necessary characteristics for oculomotor muscles surgery

Comparison of bifoveal fusion recovery efficiency using synoptophore and the liquid crystal glasses in children operated for esotropia

Purpose. This study aims to analyze sensory fusion recovery using method of  LCD glasses with  alternating occlusion of  visual  fields  and compare its efficacy with orthoptic treatment using synoptophore.Material  and methods.  Eighty-six  patients  with  prior  esotropia, post-operative absence of bifoveal fusion and residual angle of deviation <10° were studied. All patients were hyperopic. All of them underwent synoptophore treatment for 12 months (3–4 courses). Forty-three patients unsuccessful in bifoveal fusion recovery underwent treatment with LCD glasses for 6 hours/day.Results. Bifoveal fusion and binocular vision were significantly more often recovered (P<0,000) by LCD glasses treatment as compared to the synoptofore treatment. The stable bifoveal fusion was formed in 29 (67%) and 16 (18%) children, the unstable one –  in 11 (26%) and 17 (20%); the treatment was ineffective  in 3  (7%) and 53  (62%) patients,  respectively. Binocular vision was obtained in 20 (46%) and 21 (24%) patients, and taking into account the subsequent diplopic treatment in cases with stable sensory fusion in 10 (23%) and 2 (2%), respectively. Parents were more satisfied with the treatment by LCD glasses because of the lack of frequent visits to the hospital.Conclusion. Alternating occlusion of visual fields with LCD glasses is a more effective mean of bifoveal fusion and binocular vision recovery than orthoptic treatment with a synoptophore in patients after successful strabismus surgery

STRABO care less traumatic strabismus surgery technique in the rehabilitation of patients with strabismus

Purpose. Comparative evaluation of patients’ rehabilitation using less traumatic STRABO care technique and traditional methods of strabismus surgery. Material and methods. Sixty-two patients with esotropia were included in the study. All participants underwent medial rectus muscle recession and lateral rectus muscle plication. Patients were divided into two groups. In the main group (38 patients), the surgery was performed with less traumatic technique. Radio-wave knife was used for dissecting the connective tissues. Vicryl 7-0 was used as suture material. Traditional surgical technique was used in control group (24 patients). Scissors were used as a cutting tool and Vicryl 6-0 as a suture material. In the postoperative period conjunctival hyperemia, and width of the palpebral fissure were assessed after the surgery. Conjunctival flap edema (thickness) was measured one day after surgery by the anterior segment optical coherence tomography (AS-OCT). Results. The 1st day after surgery the median thickness of the conjunctival flap above the recession site according to AS-OCT was on average 1.5 times thinner in the main group than in the control group: 405 (351–555) µm vs. 618 (513–732) µm; p<0.001. During the entire observation period in the eyes operated with less traumatic technique, hyperemia was less expressed and palpebral fissure was wider as compared to the control group, where the standard surgical technique was used. Conclusion. Less traumatic STRABO care surgical technique allows to reduce the inflammatory response of tissues in response to surgical intervention and to facilitate the course of the early postoperative period