Objective: To test the construct validity of a low cost, low fidelity vitreoretinal surgical simulator Design: Construct validity study. Six microsurgical dexterity tasks, performed on a low cost vitreoretinal surgical simulator, were graded using a scoring rubric designed to assess microsurgical dexterity. Tasks one and two were dominant hand exercises, tasks three-five required bimanual dexterity and task six assessed visualization through a retinal viewing system The scores of a novice group (Ophthalmology residents who had never performed a pars planar vitrectomy) were compared to an expert group (Vitreoretinal surgeons who had performed in excess of 20 pars planar vitrectomies). Scores were graded via video recordings of the tasks, by blinded independent graders using a scoring rubric. Participants: The novice group of surgeons included 8 ophthalmology residents training at the Groote Schuur hospital department of Ophthalmology. The expert group of surgeons included 5 vitreoretinal surgeons working at the Groote Schuur hospital department of Ophthalmology, and 2 vitreoretinal surgeons working in the private sector in Cape Town, South Africa. Results: Expert surgeons performed significantly better( P=< 0.05) than the novice surgeons across all six microsurgical dexterity tasks. Greater differences were seen in bimanual tasks(tasks three-five) and in task six that was designed specifically to assess the surgeon's ability to ensure good visualisation through a retinal viewing system. Conclusions: The microsurgical dexterity tasks performed on This low cost, low-fidelity vitreoretinal surgical simulator can distinguish between novice and expert retinal surgeons demonstrating significant construct validity. Its use can be encouraged in the training of novice vitreoretinal surgeons.

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1 Abstract Introduction The vitreoretinal (VR) interface of the eye is a dynamically evolving environment which significantly influences and indicates the course of macular disorders. The main topic of the presented paper is research on the VR interface in relation to surgery on diabetic macular edema (ME), partial macular defects (PMD) and idiopathic macular holes (IMH). Aims The aims of the research were to find out new knowledge about specific characteristics of and changes in the VR interface in eyes with diabetic ME, PMD and IMH, namely with main attention focused on the internal limiting membrane (ILM) of the retina and the epimacular membrane (EMM). Methods Histopathologic and morphometric analyses were carried out on samples of the ILM of the retina and the EMM which were taken during pars plana vitrectomy (PPV) of eyes of sets of patients with diabetic ME, PMD and IMH. The analytic results were statistically evaluated and interpreted in relation to clinical factors and anatomical results of the PPV. Results Treatment of diabetic ME with removal of the ILM resulted in improved visual acuity (VA), at minimum 2 lines on the ETDRS table, in 51.8% surgically treated eyes and remained the same in 33.9% of eyes. A comparison study confirmed that PPV with preserving of the ILM achieved a long-term...

1 Abstract Introduction The vitreoretinal (VR) interface of the eye is a dynamically evolving environment which significantly influences and indicates the course of macular disorders. The main topic of the presented paper is research on the VR interface in relation to surgery on diabetic macular edema (ME), partial macular defects (PMD) and idiopathic macular holes (IMH). Aims The aims of the research were to find out new knowledge about specific characteristics of and changes in the VR interface in eyes with diabetic ME, PMD and IMH, namely with main attention focused on the internal limiting membrane (ILM) of the retina and the epimacular membrane (EMM). Methods Histopathologic and morphometric analyses were carried out on samples of the ILM of the retina and the EMM which were taken during pars plana vitrectomy (PPV) of eyes of sets of patients with diabetic ME, PMD and IMH. The analytic results were statistically evaluated and interpreted in relation to clinical factors and anatomical results of the PPV. Results Treatment of diabetic ME with removal of the ILM resulted in improved visual acuity (VA), at minimum 2 lines on the ETDRS table, in 51.8% surgically treated eyes and remained the same in 33.9% of eyes. A comparison study confirmed that PPV with preserving of the ILM achieved a long-term...

<p>Optical interrogation techniques are particularly well-suited for imaging tissue morphology, biological dynamics, and disease pathogenesis by providing noninvasive access to subcellular-resolution diagnostic information. State-of-the-art spectral domain optical coherence tomography (SDOCT) systems provide real-time optical biopsies of in vivo tissue, and have demonstrated clinical potential, particularly for applications in ophthalmology. </p><p>Recent advances in microscopy and endoscopy have led to improved resolution and compact optical designs, beyond those of conventional imaging systems. Application of encoded and multiplexed illumination and detection schemes may allow for the development of optical tools that surpass classical imaging limitations. Furthermore, complementary technologies can be combined to create multimodal optical imaging tools with advantages over current-generation systems. </p><p>In this dissertation, the development of coherence-gated and resolution-multiplexed technologies, aimed towards applications in human vitreoretinal imaging is described. Technology development in coherence-gated systems included increasing the imaging range of SDOCT by removing the complex conjugate artifact, improving acquisition speed using a scanning spectrometer design and a two-dimensional detector array, and hardware and algorithmic implementations that facilitated imaging of Doppler flow. </p><p>Structured illumination microscopy techniques were applied for resolution enhancement, and a spectrally encoded ophthalmic imaging system was developed for en face confocal fundus imaging through a single-mode fiber. These devices were resolution-multiplexed extensions of existing ophthalmic imaging devices, such as scanning laser ophthalmoscopes (SLO), which demonstrated improved resolution and more compact optical designs as compared to their conventional counterparts.</p><p>Finally, several multimodal ophthalmic diagnostic tools were developed that combined the advantages of OCT with existing imaging devices. These included a combined SLO-OCT system and a vitreoretinal surgical microscope combined with OCT. These devices allowed for concurrent ophthalmic imaging using complementary modalities for improved visualization and clinical utility.</p> / Dissertation

Les Lymphomes Primitifs Vitréo-Rétiniens (LPVR) représentent un sous-type de Lymphome Primitif du Système Nerveux Central (LPSNC). Ces hémopathies très rares sont caractérisées par leur localisation anatomique atypique, dans des sites physiologiquement dépourvus de lymphocytes B. Les lymphomes du SNC sont rattachés histologiquement aux Lymphomes B Diffus à Grandes Cellules (LBDGC) de type post-germinatif (ABC). L’objectif de notre étude était de définir le répertoire immunologique (chaînes lourdes et légères) des LPVR et des LPSNC, et de les comparer aux LBDGC. Nous avons mené une étude immunologique détaillée de ces tumeurs afin de rechercher des éléments de réponse expliquant ces localisations ectopiques. Notre projet, réalisé sur la plus grande série de LPVR à ce jour, a mis en évidence un biais de répertoire majeur, avec une sur-représentation massive du gène IGHV4-34 (63,6% des cas), significativement plus utilisé dans les LPVR comparativement aux LPSNC et aux LBDGC systémiques. Bien que la proportion de ce gène soit élevée dans d’autres SLP, cette fréquence n’a jamais été atteinte. Un subset a été décrit pour 50% des LPVR utilisant le gène IGHV3-7. Ces données suggèrent fortement l’implication d’un antigène dans leur développement. En conclusion, le LPVR représente un modèle surprenant et singulier de lymphome dirigé par l’antigène, dont l’identification offrirait des perspectives physiopathologiques et thérapeutiques prometteuses. / Primary vitroretinal lymphoma (PVRL) is a high-grade lymphoma considered as a subtype of primary central nervous system lymphoma (PCNSL). Unusual localization is a feature of these rare entities. The vast majority of cases are diffuse large B cell lymphoma (DLBCL), mostly of activated B-cell (ABC). To investigate whether PVRLs display a specific IG repertoire contributing to explain their unusual localization, we analysed in detail the IG heavy and light chain sequences from PVRL and PCNSL cases, and we compared their repertoire to that of a publicly available IG heavy chain sequences dataset from systemic ABC-type DLBCLs. Our study was carried out on the largest PVRL series reported to date and showed that PVRL displayed a strikingly biased repertoire as the IGHV4-34 gene was used in 63.6% of cases. The frequency was significantly higher in PVRL compared to PCNSL and DLBCL. This gene has been repeatedly found to be preferentially used in various B-cell malignancies, but never to such an extent. Half of PVRL cases expressing the IGHV3-7 gene had stereotyped VH CDR3 features (subset). Altogether our data showed that PVRLs display a very biased IG repertoire strongly suggesting that antigen selection plays a major role in their development. Thus, PVRL display a highly restricted IG repertoire indicative of antigen selection, and distinct from that of PCNSL. Antigen(s) identification may provide promising perspectives in physiopathology concepts and therapeutic approaches.