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- September 2014
September 2014
We present a novel fully automated algorithm for the detection of retinal diseases via optical coherence tomography (OCT) imaging. Our algorithm utilizes multiscale histograms of oriented gradient descriptors as feature vectors of a support vector machine based classifier. The spectral domain OCT data sets used for cross-validation consisted of volumetric scans acquired from 45 subjects: 15 normal subjects, 15 patients with dry age-related macular degeneration (AMD), and 15 patients with diabetic macular edema (DME). Our classifier correctly identified 100% of cases with AMD, 100% cases with DME, and 86.67% cases of normal subjects. This algorithm is a potentially impactful tool for the remote diagnosis of ophthalmic diseases.
PURPOSE: The aim of this study was to develop a modified ex vivo corneal cross-linking method that increases stromal resistance to enzymatic degradation for use as a carrier for the Boston keratoprosthesis. METHODS: Ex vivo cross-linking of human corneas was performed using Barron artificial anterior chambers. The corneas were deepithelialized, pretreated with riboflavin solution (0.1% riboflavin/20% dextran), and irradiated with ultraviolet A (UV-A) light (λ = 370 nm, irradiance = 3 mW/cm) for various durations. The combined effect of UV-A and gamma (γ) irradiation was also assessed using the commercially available γ-irradiated corneal donors. The corneas were then trephined and incubated at 37°C with 0.3% collagenase A solution. The time to dissolution of each cornea was compared across treatments. RESULTS: Deepithelialized corneas (no UV light, no riboflavin) dissolved in 5.8 ± 0.6 hours. Cross-linked corneas demonstrated increased resistance to dissolution, with a time to dissolution of 17.8 ± 2.6 hours (P < 0.0001). The corneal tissues' resistance to collagenase increased with longer UV-A exposure, reaching a plateau at 30 minutes. Cross-linking both the anterior and posterior corneas did not provide added resistance when compared with cross-linking the anterior corneas only (P > 0.05). γ-irradiated corneas dissolved as readily as deepithelialized controls regardless of whether they were further cross-linked (5.6 ± 1.2 hours) or not (6.1 ± 0.6 hours) (P = 0.43). CONCLUSIONS: Collagen cross-linking of the deepithelialized anterior corneal surface for 30 minutes conferred optimal resistance to in vitro keratolysis by collagenase A.
BACKGROUND: Choroidal neovascularization (CNV) is the main cause of vision loss in age-related macular degeneration (AMD). In experimental CNV, endothelial progenitor cells (EPCs) contribute to the formation of new vessels. The aim of this study was to investigate whether the behavior of EPCs in patients with AMD supports a role for EPCs in human CNV. METHODS: The number of circulating EPCs that are considered pure endothelial precursors and EPCs with monocytic characteristics, and the plasma levels of regulatory cytokines were evaluated in 23 patients with AMD with active CNV and 20 matched controls. In the patients, this profile was re-evaluated after ranibizumab. RESULTS: When compared with controls, the patients with AMD showed a lower number of both EPC types (P = 0.03) and higher plasma levels (P = 0.03) of stromal cell-derived factor 1. Three monthly injections of ranibizumab returned to control levels the number of circulating EPCs considered pure endothelial precursors and of stromal cell-derived factor 1, but not of monocytic EPCs. CONCLUSION: The observations indicate responsiveness of circulating EPCs to the CNV process in AMD. They suggest the hypothesis that increased stromal cell-derived factor 1 production at the CNV site (reflected in higher plasma levels) recruits EPCs from the circulation, and that antivascular endothelial growth factor therapy selectively decreases the recruitment of cells to be incorporated into new vessels.
PURPOSE: To report a novel surgical technique for lower eyelid involutional ectropion repair using a lateral tarsal strip and internal retractor reattachment procedure involving full-thickness eyelid sutures. METHODS:: A retrospective review was performed of patients who underwent repair of involutional ectropion via lateral tarsal strip and internal retractor reattachment with full-thickness eyelid sutures by 1 surgeon. Patients having concomitant or previous eyelid surgical procedures were excluded. Collected data included patient demographics, surgical outcomes, and length of follow up. RESULTS:: Forty-one lower eyelids of 31 patients with involutional ectropion underwent surgical repair. There were 17 men and 14 women in the age range of 69 to 92 years (mean age 82.2 ± 5.9 years). Surgical sites included 22 right and 19 left lower eyelids. Follow up ranged from 1 to 48 months with an average of 5.9 months. Surgical success with anatomical correction of involutional ectropion was achieved in 39 of 41 eyelids (95.1%). There were no perioperative or postoperative complications. Two of 41 (4.9%) eyelids had recurrence of ectropion 7 and 18 months after the procedure. CONCLUSIONS:: This procedure combining lateral tarsal strip with internal retractor reattachment involving full-thickness eyelid sutures effectively addresses horizontal eyelid laxity and tarsal instability, providing an effective technique to correct involutional ectropion of the lower eyelid.
: A critical review of the literature indicates that idiopathic opticochiasmatic arachnoiditis, once considered an important consideration in patients with otherwise unexplained optic atrophy, is not a valid disease entity.
PURPOSE: To design, fabricate, and evaluate novel materials to remove silicone oil (SiO) droplets from intraocular lenses (IOL) during vitreoretinal surgery. METHODS: Three different designs were fabricated using soft lithography of polydimethylsiloxane (PDMS), three-dimensional (3D) inverse PDMS fabrication using water dissolvable particles, and atomic layer deposition (ALD) of alumina (Al2O3) on surgical cellulose fibers. Laboratory tests included static and dynamic contact angle (CA) measurements with water and SiO, nondestructive x-ray microcomputer tomography (micro-CT), and microscopy. SiO removal was performed in vitro and ex vivo using implantable IOLs and explanted porcine eyes. RESULTS: All designs exhibited enhanced hydrophobicity and oleophilicity. Static CA measurements with water ranged from 131° to 160° and with SiO CA approximately 0° in 120 seconds following exposure. Nondestructive x-ray analysis of the 3D PDMS showed presence of interconnected polydispersed porosity of 100 to 300 μm in diameter. SiO removal from IOLs was achieved in vitro and ex vivo using standard 20-G vitrectomy instrumentation. CONCLUSION: Removal of SiO from IOLs can be achieved using materials with lower surface energy than that of the IOLs. This can be achieved using appropriate surface chemistry and surface topography. Three designs, with enhanced hydrophobic properties, were fabricated and tested in vitro and ex vivo. All materials remove SiO within an aqueous environment. Preliminary ex vivo results were very promising, opening new possibilities for SiO removal in vitreoretinal surgeries. TRANSLATIONAL RELEVANCE: This is the first report of an instrument that can lead to successful removal of SiO from the surface of IOL. In addition to the use of this instrument/material in medicine it can also be used in the industry, for example, retrieval of oil spills from bodies of water.
Purpose: To investigate whether systemically-injected syngeneic mesenchymal stem cells (MSCs) can home to the inflamed transplanted cornea, suppress induction of alloimmunity, and promote allograft survival. Methods: MSCs were generated from bone marrow of wild-type BALB/c or GFP+ C57BL/6 mice, and 1x106 cells were intravenously injected to allografted recipients 3 hours after surgery. MSCs homing to the cornea were examined at day 3 post-transplantation by immunohistochemistry. CD11c+MHC II+ cells were detected in the cornea and lymph nodes (LNs) 14 days post-transplantation using flow cytometry. Cytokine expression of bone marrow-derived dendritic cells (BMDCs) was determined using real-time PCR. ELISPOT assay was used to assess indirect and direct host T cell allosensitization, and graft survival was evaluated by slit-lamp biomicroscopy weekly up to 8 weeks. Results: Intravenously injected GFP+ MSCs were found in abundance in the transplanted cornea, conjunctiva, and lymph nodes, but not in the ungrafted (contralateral) tissue. The frequencies of mature CD11c+MHC II+ APCs were substantially decreased in the corneas and draining LNs of MSC-injected allograft recipients compared to control recipients. Maturation and function of in vitro cultured BMDCs was decreased when cocultured with MSCs. Draining LNs of MSC-injected allograft recipients showed significantly lower frequencies of IFNγ-secreting Th1 cells compared to the control group. Allograft survival rate was significantly higher in MSC-injected recipients compared to non-MSC injected recipients. Conclusions: Our data demonstrate that systemically-administered MSCs specifically home to transplanted corneas and promote allograft survival by inhibiting APC maturation and induction of alloreactive T cells.
Proliferative vitreoretinopathy (PVR) is a nonneovascular blinding disease and the leading cause for failure in surgical repair of rhegmatogenous retinal detachments. Once formed, PVR is difficult to treat. Hence, there is an acute interest in developing approaches to prevent PVR. Of the many growth factors and cytokines that accumulate in vitreous as PVR develops, neutralizing vascular endothelial growth factor (VEGF) A has recently been found to prevent PVR in at least one animal model. The goal of this study was to test if Food and Drug Administration-approved agents could protect the eye from PVR in multiple animal models and to further investigate the underlying mechanisms. Neutralizing VEGF with aflibercept (VEGF Trap-Eye) safely and effectively protected rabbits from PVR in multiple models of disease. Furthermore, aflibercept reduced the bioactivity of both experimental and clinical PVR vitreous. Finally, although VEGF could promote some PVR-associated cellular responses via VEGF receptors expressed on the retinal pigment epithelial cells that drive this disease, VEGF's major contribution to vitreal bioactivity occurred via platelet-derived growth factor receptor α. Thus, VEGF promotes PVR by a noncanonical ability to engage platelet-derived growth factor receptor α. These findings indicate that VEGF contributes to nonangiogenic diseases and that anti-VEGF-based therapies may be effective on a wider spectrum of diseases than previously appreciated.
Hypotropia following orbital fracture repair is traditionally attributed to residual tissue entrapment, scarring, direct muscle injury, or damage to the branches of the oculomotor nerve serving the inferior oblique or inferior rectus muscles. We present a case of acquired hypotropia and incyclotropia that occurred following repair of an orbital fracture involving the floor and medial wall. In order to enable adequate visualization and treatment of the combined fractures, access via a transcaruncular approach and disinsertion of the inferior oblique muscle at its origin was necessary. Whereas the possibility of inferior oblique paresis due to repair of an orbital fracture via the transcaruncular approach has received some acknowledgment, there are no prior reports in the ophthalmic literature. Strabismus surgeons should be aware of this possibility when planning surgical correction of hypotropia and incyclotropia in similar cases.
