Equalização em receptores de televisão digital de alta definição utilizando modulação 8VSB

Orientador : Jose Geraldo ChiquitoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoDoutorad

In vivo confocal microscopy of verticillata-like paraproteinemic keratopathy in a patient with monoclonal gammopathy of uncertain significance evolving into smoldering multiple myeloma

Purpose: To highlight the utility of in vivo confocal microscopy (IVCM) in the microstructural characterization of corneal deposits resembling vortex keratopathy in a case of secondary deposition keratopathy due to an evolving monoclonal gammopathy. Observations: A 56-year-old Caucasian woman previously diagnosed with monoclonal gammopathy of undetermined significance (MGUS), exhibited bilateral diffuse sub-epithelial and anterior stromal opacities distributed in a whorl-shaped pattern. IVCM examination permitted analysis of the microstructural features and distribution of the opacities in different corneal layers. Deposits resembling those reported in multiple myeloma rather than MGUS were detected, and the patient's hematologist was subsequently advised to re-evaluate the earlier diagnosis. Two months later, a bone marrow biopsy led to a diagnosis of plasma cell myeloma. Conclusions and importance: It is suggested that cornea verticillata-like paraproteinemic keratopathy (PPK) in MGUS might be predictive of disease evolution to plasma cell myeloma. Characteristic deposits and morphological features revealed by IVCM may be helpful for non-invasive assessment or screening in patients with hematological disorders

Glaucoma surgery during the first year of the COVID-19 pandemic

Purpose: To summarize the actions taken to give continuity to the surgical treatment of glaucoma patients and to present the volume and characteristics of glaucoma surgery in the first year of pandemic at the Tertiary Glaucoma Center of the University Hospital of Verona (Veneto, Italy). Methods: Demographical and surgical features of patients who underwent glaucoma surgery from March 9th, 2020 to March 8th, 2021 have been collected and compared to the same date range of the previous year. The analyzed data included age, gender, region of origin, glaucoma staging, type of anesthesia and surgical procedure. Results: The surgical volume of glaucoma has dropped by 30.1%. In comparison with the previous year, we found a significant variation in the overall distribution of the performed surgical procedures (p < 0.001). There was a decline in Baerveldt tube implants (- 4.9%), and an increase of non-penetrating surgery (+ 2.6%), cyclo-photo ablative procedures (+ 4.2%) and MIGS (+ 5.7%). Only 24.3% of the procedures were performed under general anesthesia compared to 41.5% in the pre-pandemic period (p < 0.001). The number of procedures performed on eyes affected by advanced or end-stage glaucoma is doubled (p < 0.001). Conclusions: To give continuity to glaucoma surgery, we prioritized interventions on patients with poorer visual fields, rapidly progressing visual field deficit and elevated IOP uncontrolled by maximal medical therapy. Secondly, we have rescheduled the other interventions following the same priority criteria. Finally, we managed some lower priority cases with MIGS, minimizing the need for close post-intervention follow-up. Considering the negative consequences that a delay in the management of glaucoma can have in terms of visual loss, the closure of the operating rooms in the first quarter of the pandemic was detrimental. It appears that glaucoma surgery deserves urgencies that cannot be overshadowed and the greatest effort must be to give continuity to this type of eye surgery

Femtosecond laser-assisted implantation of corneal stroma lenticule for keratoconus

PURPOSE: To review recent progress, challenges, and future perspectives of stromal keratophakia for the treatment of advanced keratoconus. METHODS: We systematically reviewed the literature in the PubMed database, last update June 30, 2020. No language restriction was applied. The authors checked the reference lists of the retrieved articles to identify any additional study of interest.RESULTS: Several techniques have been proposed for the treatment of keratoconus in order to avoid or delay keratoplasty. This was primarily due to the lack of accessibility to donor corneas in many countries. The ease and predictability of the more advanced femtosecond lasers used to correct ametropias by stromal lenticule extraction lead to hypothesize that generated refractive lenticules could be implanted into corneal stromal layers to restore volume and alter the refractive properties of the cornea in patients with corneal ectasias. At the same time, new techniques for preservation, customization, and cellular therapy of the corneal stromal have been developed, directing to the valorization of otherwise discarded byproducts such as donor corneas unsuitable for either lamellar of penetrating keratoplasty.CONCLUSIONS: Femtosecond laser-assisted stromal keratophakia could be a suitable therapeutic option for the treatment of corneal ectasias, especially in patients with advanced keratoconus, providing biomechanical support recovering the pachimetry to nearly normal value at the same time. The accuracy and predictability of the refractive outcome are yet a critical issue and the patient eligible for the procedure still has to be characterized

Topographic and biomechanical changes after application of corneal cross-linking in recurrent keratoconus

Background: Recurrent keratoconus (RKC) develops as a progressive thinning of the peripheral and the inferior cornea after keratoplasty, in both graft and host, causing secondary astigmatism, refractive instability, and reduced visual acuity. We evaluated the effectiveness of corneal cross-linking (CXL) in patients diagnosed with RKC. Methods: Accelerated-CXL via the epi-off technique was performed in15 patients (18 eyes) diagnosed with RKC. Topographic and biomechanical changes were assessed at 12 months. Results: Differences in maximum keratometry, thinnest corneal thickness, and biomechanical parameters (deformation amplituderatio, inverse concave radius, applanation 1 velocity, and applanation 2 velocity, stiffness A1) versus baseline were statistically significant (p < 0.05).Best corrected visual acuity was improved in 13 eyes and unchanged in 4;manifest refractive spherical equivalent was reduced in 13 eyes, increased in 3,and unchanged in 1 eye; topographic astigmatism was reduced in 9 eyes, remained stable in 1 eye, and increased in 7 eyes. Conclusions: Improved topographic and biomechanic indexes at 1 year after CXL suggest it's potential as first-line therapy for RKC, as it is for KC

Femtosecond laser-assisted big-bubble deep anterior lamellar keratoplasty

Purpose: To determine whether type 1 big-bubble (BB) formation is influenced by the sequence of incisions created with the Victus femtosecond laser (FSL) enabled with software version 3.4 (SV 3.4) during deep anterior lamellar keratoplasty (DALK). Materials and Methods: Consecutive FSL-assisted DALK BB procedures were performed on 20 human donor corneas: 10 shaped by tunnel incision followed by lamellar incision (tunnel-lamellar group, TL) and 10 in the reverse order (lamellar-tunnel group, LT). The BB type was assessed by evaluating dynamic air movement during air inflation; bubble diameter and floor thickness were measured by anterior segment optical coherence tomography. Results: Overall, a type 1 BB formed in 85% of eyes: 100% in the TL group and 70% in the LT group. In the LT group, a type 2 BB formed in 2 corneas and one cornea was perforated during cannula insertion. Type 1 BB was achieved after one attempt in 90% of eyes in the TL group and in 57% in the LT group. Conclusion: Shaping the tunnel before rather than after lamellar incision may be more effective for obtaining a type 1 BB by air injection

The role of topical povidone-iodine in the management of infectious keratitis: a pilot study

The aim of this prospective explorative study was to evaluate the safety and the effectiveness of topical polyvinylpyrrolidone-iodine (PVP-I) administered during the time-to-results period for pathogen identification and susceptibility testing in patients with infectious keratitis (IK). A corneal swab (CS) for antimicrobial evaluation was performed at enrollment (T0) and topical 0.66%-PVP-I was administered until the laboratory results were available (T1). Ulcer and infiltrate areas and infiltrate depths were compared between T0 and T1 (i.e., time-to-result period). Patients were then shifted to a specific antimicrobial therapy and followed up until resolution of their infiltrates (Tlast-TL). Twenty-five eyes were enrolled, and none showed clinical worsening leading to protocol withdrawal. At T1, ulcer and infiltrate areas showed significant improvement in Gram-positive IK (n = 13-52%; p = 0.027 and p = 0.019, respectively), remained stable in fungal IK (n = 5-20%; both p = 0.98) and increased in those with Gram-negative bacteria (n = 4-16%; p = 0.58 and p = 0.27). Eyes with negative cultures (n = 3-12%) showed complete resolution at T1 and did not initiate any additional antimicrobial therapy. The administration of 0.66% PVP-I during the time-to-result period seems to be a safe strategy in patients with IK while often sparing broad-spectrum antimicrobial agents. In addition, it showed to be effective in eyes with a Gram-positive bacterial infection

Microscopic corneal epithelial changes and clinical outcomes in simple limbal epithelial transplantation surgery after treatment with amniotic membrane eye drops (AMED): A case report

Purpose: To describe the microscopic epithelial changes and the clinical outcomes of a patient treated with amniotic membrane eye drops (AMED) because of a persistent epithelial defect (PED) and a partial limbal stem cell deficiency (LSCD) after simple limbal epithelial transplantation (SLET) and deep anterior lamellar keratoplasty (DALK). Observations: A 72-year-old patient, who had previously undergone SLET and DALK due to a total LSCD, presented with a PED related to a partial LSCD, and was treated with AMED for one month. We evaluated the patient's visual acuity, the Oxford grading scale, the Wong-Baker Pain Rating Scale, and in vivo confocal microscopy, both at baseline and 3 months after the end of treatment. Visual acuity improved from 0.5 to 0.4 LogMAR, the Oxford grading scale changed from grade III to grade I and the Wong-Baker Pain Rating Scale from grade 4 to grade 1. The corneal surface, which initially showed conjunctival characteristics over approximately 50% of the whole area, consisted mainly (75%) of mature corneal epithelium 3 months after the end of treatment. Conclusions and importance: While improving symptoms and clinical characteristics, AMED was also able to restore the normal corneal epithelium's morphology in a case of partial LSCD after SLET and DALK

Eight months follow-up of corneal nerves and sensitivity after treatment with cenegermin for neurotrophic keratopathy

Backgroud: Cenegermin (Oxervate, Dompè Farmaceutici, Milan, IT), a recombinant human NGF, is a potentially healing new drug for neurotrophic keratopathy (NK), a rare but challenging disease affecting the cornea. To date, studies that evaluate its mid-term effect on corneal nerves and sensitivity are lacking. Objective: To evaluate the recovery and morphology of subbasal corneal nerves in patients treated with Cenegermin for NK and assess their correlation with corneal sensitivity. Methods: This prospective, observational case series study was carried out between May 2018 and August 2020 at the Ophthalmic Clinic of the University of Verona. Clinical evaluation, sensitivity, and in vivo confocal microscopy (IVCM) were performed in the central and all four corneal sectors at baseline, the end of therapy (8 weeks), and 2, 4, and 8 months after therapy. Consecutive patients with NK (stage 2-3), treated with Cenegermin (1 drop 6 times daily for 8 weeks), were enrolled. During each visit, Corneal nerve fiber length (CNFL), corneal nerve fiber total branch density (CTBD), corneal nerve fiber fractal dimension (CNFraD) and Cochet-Bonnet esthesiometry (CBE) were measured. Results: We enrolled 18 patients. Complete NK healing was noted in 14/18(78%) patients after 8 weeks of treatment; then in 14(78%), 15(83%), and 13(72%) patients at 2-, 4-, and 8-months, respectively. Starting at 8 weeks through 4-month follow-up there was progressive improvement in CBE in all corneal sectors (p ≤ 0.01), which continued thereafter. There was significant corneal nerve regrowth especially in the peripheral cornea: centripetal progression starting at 8 weeks (CNFL and CNFrad) and significant branching starting at 2 months (CTBD), which continued through to the end of follow up. Sector-coupled IVCM and CBE findings correlated at all evaluations (all r ≥ 0.62 starting at 2 months, with highest values in the peripheral sectors). Conclusions: After Cenegermin we observed a subbasal corneal nerve regeneration, a recovery of sensitivity and a lasting epithelial healing, suggesting that the effect of its action persists several months after discontinuation in patients with NK