[Assessment of anterior segment anatomy by OCT after non penetrating deep sclerectomy]. / Analyse de l'architecture du segment antérieur par OCT après sclérectomie profonde non perforante.

PURPOSE: Thanks to recent progress in imaging techniques, the anatomy of the anterior segment can be measured accurately and noninvasively. The objective of this study was to assess early postoperative changes induced by non penetrating deep sclerectomy (NPDS) on anterior chamber depth, anterior chamber angle and central corneal thickness. PATIENTS AND METHODS: Twenty eyes of 20 patients with primary open-angle glaucoma (POAG) that underwent NPDS were studied. All patients underwent ophthalmologic examination including non invasive analysis of the anterior segment architecture. Visante(®) OCT was used to determine anterior chamber depth, central corneal thickness, scleral spur angle (SSA), angle opening distance at 500µm (AOD 500), and trabecular-iris space area at 500 µm (TISA 500) in the nasal and temporal quadrants. These evaluations were performed at 1 day preop, then day 1, day 7 and day 30 after surgery. RESULTS: Preoperatively, SSA, AOD 500 and TISA 500 were 37.24 ± 12.67°, 0.42 ± 0.25 mm and 0.15 ± 0.1 mm(2), respectively, in the nasal quadrant, and 39.62 ± 12.41°, 0.46 ± 0.25 mm and 0.16 ± 0.08 mm(2), respectively, in the temporal quadrant. Mean anterior chamber depth, central corneal thickness and intraocular pressure (IOP) were 3.09 ± 0.54 mm, 530 ± 34.3 µm and 20.43± 7.25 mmHg respectively. After NPDS, aside from IOP being significantly decreased on day 1 (5.57 ± 2.78 mmHg, P<0.0001), day 7 (8.2 ± 3.12 mmHg, P<0.0001) and day 30 (13.4 ± 3.47 mmHg, P=0.001), none of the other study parameters was significantly modified. CONCLUSION: No relationship was found between IOP and anterior chamber architecture after NPDS. NPDS appears to significantly reduce IOP while maintaining the architecture of the anterior chamber, and in particular, the anterior chamber angle.

Intertrial coherence and causal interaction among independent EEG components.

Over the past few years there has been an increased interest in studying the underlying neural mechanism of attention and cognitive brain activity. This paper aims towards identifying and analyzing distinct responses in an auditory working memory paradigm, as independent components with variable latency, frequency and phase characteristics. The event-related nature of components (either phase or non-phase-locked) over multiple trials is thoroughly examined through intertrial coherence measures. Furthermore, the functional coupling of independent components is investigated through the concept of partial directed coherence depicted as a directed graph. Using these tools, the paper compares issues of activation, connectivity and directionality in the synchronization maps of two populations, of control and Alzheimer's subjects. The results on real data from an oddball experiment verify and further enhance the findings of previous studies and illustrate the potential of the proposed analysis framework.

[Utility of the Visante OCT in the follow-up of glaucoma surgery]. / Apport de l'OCT-Visante dans le suivi de la chirurgie du glaucome.

PURPOSE: To evaluate the utility of the Visante OCT in the follow-up of filtering surgery. MATERIAL: and methods: In this study, we evaluated 38 filtering blebs in 31 patients following trabeculectomy (4) and nonpenetrating deep sclerectomy (NPDS). In 11 cases, mitomycin C was used during surgery. In patients who underwent NPDS, a collagen implant was placed within the scleral site in eight eyes and seven eyes had goniopuncture during follow-up. All patients had complete ophthalmologic examination with morphological evaluation of the bleb and intraocular pressure measurement as well as Visante OCT evaluation. RESULTS: The trabeculectomy site as well as the trabeculodescemetic membrane (in NPDS), the scleral flap, the conjunctival flap, the iris, and the relationship between these structures were analyzed. Functioning blebs had a hyporeflective and irregular conjunctival tissue associated with a route for aqueous humor under the scleral flap from the anterior chamber toward the subconjunctival space. This filtration route was also observed within nonfunctioning encapsulated blebs. Flat and encapsulated nonfunctioning blebs had dense and hyperreflective conjunctival tissue. In the particular case of nonfunctioning flat blebs, there was no route for aqueous humor filtration under the scleral flap. CONCLUSION: The Visante OCT is a simple and noninvasive imaging technique with good resolution, allowing the analysis of morphologic changes occurring in eyes after filtering surgery.

[Contribution of in vivo confocal microscopy to limbal tumor evaluation]. / Apport de la microscopie confocale in vivo dans l'exploration de tumeurs limbiques.

PURPOSE: To explore tumors of the limbus with a new in vivo confocal microscope and to compare the images to histology results. METHODS: We evaluated three tumors in three patients with the Heidelberg Retina Tomograph II, Rostock Cornea Module. A diagnostic and therapeutic excision with adjunctive cryotherapy was performed for each individual. Confocal microscopy was compared to histopathologic sections. RESULTS: Histology identified two dysplasias and one carcinoma in situ. The main pathological features were visible on our images: cytonuclear atypias, epithelial folds into an inflammatory and vascularized conjunctival stroma, fine vessels perpendicular to the surface, a clear limit with normal epithelium, papillomatous organization, and abnormal keratinization. CONCLUSION: Our preliminary study showed that this type of limbal tumor could be explored using in vivo confocal microscopy. We were not able to determine whether there was a microinvasion. This new method could be a diagnostic aid, especially for atypical lesions and for follow-up because of frequent recurrences. Other studies are necessary to confirm our hypothesis.