MARCONY RODRIGUES DE SANTHIAGO
Projetos de Pesquisa
Unidades Organizacionais
LIM/33 - Laboratório de Oftalmologia, Hospital das Clínicas, Faculdade de Medicina
11 resultados
Resultados de Busca
Agora exibindo 1 - 10 de 11
- OCT Study of the Femtosecond Laser Opaque Bubble Layer(2017) MARINO, Gustavo K.; SANTHIAGO, Marcony R.; WILSON, Steven E.PURPOSE: To characterize the location and regularity of the opaque bubble layer (OBL) in the corneal stroma after femtosecond laser-assisted LASIK (FS-LASIK) flap generation. METHODS: In this prospective study, 30 eyes of 15 patients who had FS-LASIK surgery for myopia, astigmatism, and/or hyperopia were included. Screen captures were obtained at the end of the flap creation and the eyes with hard type OBL were immediately imaged with anterior segment optical coherence tomography. RESULTS: The mean age of the 9 men and 6 women was 40 +/- 11.3 years (range: 22 to 60 years). Seven eyes (23.3%) developed hard type OBL that was typically localized in the central cornea beneath the LASIK flap and, in the majority of cases, located close to the hinge of the flap. Three of the seven eyes had OBL only within the laser cut, whereas the four other eyes had OBL in a spotty distribution within the stromal bed beneath the flap. None of the eyes had an accumulation of OBL within the flap itself. CONCLUSIONS: The excimer laser ablation of a stroma with OBL may be different from that of a stroma without OBL. Management of OBL when it occurs due to flap production, including allowing the bubble to dissipate when they overlie the pupil, is important to obtain the best outcomes with femtosecond laser-assisted LASIK.
- Microkeratome versus femtosecond flaps: accuracy and complications(2014) SANTHIAGO, Marcony R.; KARA-JUNIOR, Newton; WARING, George O.Purpose of review To update the knowledge on differences between mechanical microkeratome and femtosecond flaps for laser in-situ keratomileusis (LASIK) in terms of accuracy and complications. Recent findings Corneal flaps created with the femtosecond laser present a more planar architecture and provide greater precision in flap diameter and thickness; a more uniform flap thickness across the flap diameter and it allows the surgeon to programme the angulation of the flap periphery. Femtosecond LASIK flaps are classically related to complications derived from a more intense inflammatory response, such as diffuse lamellar keratitis and transient light-sensitivity syndrome. Newer femtosecond models allow for much lower energy delivery to cut the flap, to the point the overall inflammatory response is not significantly different from the microkeratome. The incidence of complications such as epithelial defect and flap dislocations is higher with microkeratome flaps. Summary This review examines the accuracy and complications of flaps created with femtosecond and microkeratome. Both femtosecond and microkeratome are able to create accurate LASIK flaps. Femtosecond LASIK flaps represent significant improvement in morphology and predictability with implications for safety.
- Phototherapeutic Keratectomy: Science and Art(2017) WILSON, Steven E.; MARINO, Gustavo K.; MEDEIROS, Carla S.; SANTHIAGO, Marcony R.PURPOSE: To describe, with videos, the principles of excimer laser phototherapeutic keratectomy (PTK) for the treatment of corneal scars, corneal surface irregularity, and recurrent corneal erosions. METHODS: Depending on the pathology in a treated cornea, the epithelium is removed either by transepithelial PTK ablation with the excimer laser or thorough scraping with a scalpel blade. Stromal PTK can be performed with or without photorefractive keratectomy (PRK), depending on the refractive status of both eyes. Residual surface irregularity is treated with masking-smoothing PTK. Typically, 0.02% mitomycin C treatment is applied for 30 seconds to corneas treated with PTK for scars and surface irregularity. RESULTS: Transepithelial PTK with masking-smoothing typically improves corrected distance visual acuity in the eye even if the entire stromal opacity cannot be removed and can be used to debulk surface irregularity to facilitate subsequent therapeutic customized wavefront-guided or optical coherence tomography-guided PTK or PRK. PTK for recurrent erosion is performed after thorough mechanical epithelial debridement of redundant epithelial basement membrane (EBM) with a scalpel and should only include a dusting of excimer laser to remove residual EBM without inducing central irregular astigmatism or damaging limbal tissues. Meta-analyses are provided for PTK treatment for corneal scars, corneal dystrophies, and recurrent corneal erosions. CONCLUSIONS: Excimer laser PTK is a highly effective treatment for superficial corneal scars, central corneal irregular astigmatism, and recurrent corneal erosions unresponsive to medical treatment or mechanical epithelial debridement alone.
- Corneal nerves anatomy, function, injury and regeneration(2020) MEDEIROS, Carla S.; SANTHIAGO, Marcony R.The cornea is a highly innervated tissue, exhibiting a complex nerve architecture, distribution, and structural organization. Significant contributions over the years have allowed us to come to the current understanding about the corneal nerves. Mechanical or chemical trauma, infections, surgical wounds, ocular or systemic comorbidities, can induce corneal neuroplastic changes. Consequently, a cascade of events involving the corneal wound healing, tmphic functions, neural circuits, and the lacrimal products may interfere in the corneal homeostasis. Nerve physiology drew the attention of investigators due to the popularization of modern laser refractive surgery and the perception of the destructive potential of the excimer laser to the corneal nerve population. Nerve fiber loss can lead to symptoms that may impact the patient's quality of life, and impair the best-corrected vision, leading to patient and physician dissatisfaction. Therefore, there is a need to better understand preoperative signs of corneal nerve dysfunction, the postoperative mechanisms of nerve degeneration and recovery, aiming to achieve the most efficient way of treating nerve disorders related to diseases and refractive surgery.
- Validation of the Percent Tissue Altered as a Risk Factor for Ectasia after LASIK(2019) SANTHIAGO, Marcony R.; WILSON, Steven E.; SMADJA, David; CHAMON, Wallace; KRUEGER, Ronald E.; RANDLEMAN, J. Bradley
- Mitomycin C: Biological Effects and Use in Refractive Surgery(2012) SANTHIAGO, Marcony R.; NETTO, Marcelo V.; WILSON, Steven E.Purpose: To provide an overview of the safety and efficacy of mitomycin C (MMC) as adjuvant therapy after refractive surgery procedures. Methods: Literature review. Results: Over the past 10 years, MMC has been used by refractive surgeons to prophylactically decrease haze after surface ablation procedures and therapeutically in the treatment of preexisting haze. Development of MMC treatments has had a significant role in the revival of surface ablation techniques. We reviewed the literature regarding mechanism of action of MMC, its role in modulating wound healing after refractive surgery, and its safety and efficacy as adjuvant therapy applied after primary photorefractive keratectomy surgery or after photorefractive keratectomy re-treatment after laser in situ keratomileusis and other corneal surgeries and disorders. The drug is a potent mitotic inhibitor that effectively blocks keratocyte activation, proliferation, and myofibroblast differentiation. Many studies have suggested that MMC is safe and effective in doses used by anterior surface surgeons, although there continue to be concerns regarding long-term safety. After initial depletion of anterior keratocytes, keratocyte density seems to return to normal 6 to 12 months after the use of MMC when corneas are examined with the confocal microscope. Most clinical studies found no difference between preoperative and postoperative corneal endothelial cell densities when MMC 0.02% was applied during refractive surgery, with exposure time of 2 minutes or less. Conclusions: After more than 10 years of use, MMC has been found to be effective when used for prevention and treatment of corneal haze. Questions remain regarding optimal treatment parameters and long-term safety.
- Percent tissue altered and corneal ectasia(2016) SANTHIAGO, Marcony R.Purpose of reviewThis article reviews the association of a novel metric, percentage tissue altered (PTA), with the occurrence of ectasia after laser in-situ keratomileusis in eyes with normal corneal topography, and analyses the influence of the variables that comprise it, and its role on eyes with suspicious topography.Recent findingsPTA is derived from [PTA=(FT+AD)/CCT] where FT=flap thickness, AD=ablation depth, and CCT=preoperative central corneal thickness. Our studies revealed that there is a robust relationship between high PTA and ectasia risk in eyes with normal preoperative topography. PTA higher or equal to 40% presented the highest odds ratio and highest predictive capabilities for ectasia risk than each of the variables that comprise it, residual stromal bed or age. Average thicker flaps alone were insufficient to create ectasia unless coupled with greater ablation depths, meaning a high PTA. In eyes with suspicious topography, even low PTA value is sufficient to induce ectasia.SummaryThis new metric, PTA, should be taken into account when screening patients for refractive surgery. Patients with normal topography or tomography, presenting a PTA higher or equal to 40% should be considered at higher risk for post laser in-situ keratomileusis ectasia.
- Corneal Molecular and Cellular Biology for the Refractive Surgeon: The Critical Role of the Epithelial Basement Membrane(2016) MARINO, Gustavo K.; SANTHIAGO, Marcony R.; TORRICELLI, Andre A. M.; SANTHANAM, Abirami; WILSON, Steven E.PURPOSE: To provide an overview of the recent advances concerning the corneal molecular and cellular biology processes involved in the wound healing response after excimer laser surface ablation and LASIK surgery. METHODS: Literature review. RESULTS: The corneal wound healing response is a complex cascade of events that impacts the predictability and stability of keratorefractive surgical procedures such as photorefractive keratectomy and LASIK. The generation and persistence of corneal myofibroblasts (contractile cells with reduced transparency) arise from the interaction of cytokines and growth factors such as transforming growth factor beta and interleukin 1 produced by epithelial and stromal cells in response to the corneal injury. Myofibroblasts, and the opaque extracellular matrix they secrete into the stroma, disturb the precise distribution and spacing of collagen fibers related to corneal transparency and lead to the development of vision-limiting corneal opacity (haze). The intact epithelial basement membrane has a pivotal role as a structure that regulates corneal epithelial-stromal interactions. Thus, defective regeneration of the epithelial basement membrane after surgery, trauma, or infection leads to the development of stromal haze. The apoptotic process following laser stromal ablation, which is proportional to the level of attempted correction, leads to an early decrease in anterior keratocyte density and the diminished contribution of these non-epithelial cells of components such as perlecan and nidogen-2 required for normal regeneration of the epithelial basement membrane. Haze persists until late repair of the defective epithelial basement membrane. CONCLUSIONS: Defective regeneration of the epithelial basement membrane has a critical role in determining whether a cornea heals with late haze after photorefractive keratectomy or with scarring at the flap edge in LASIK.
- Accelerated corneal collagen crosslinking: Technique, efficacy, safety, and applications(2016) MEDEIROS, Carla S.; GIACOMIN, Natalia T.; BUENO, Renata L.; GHANEM, Ramon C.; MORAES JR., Haroldo V.; SANTHIAGO, Marcony R.Corneal collagen crosslinking (CXL) is an approach used to increase the biomechanical stability of the stromal tissue. Over the past 10 years, it has been used to halt the progression of ectatic diseases. According to the photochemical law of reciprocity, the same photochemical effect is achieved with reduced illumination time and correspondingly increased irradiation intensity. Several new CXL devices offer high ultraviolet-A irradiation intensity with different time settings. The main purpose of this review was to discuss the current use of different protocols of accelerated CXL and compare the efficacy and safety of accelerated CXL with the efficacy and safety of the established conventional method. Accelerated CXL proved to be safe and effective in halting progression of corneal ectasia. Corneal shape responses varied considerably, as did the demarcation line at different irradiance settings; the shorter the exposure time, the more superficial the demarcation line. (C) 2016 ASCRS and ESCRS
- Presbyopic Excimer Laser Ablation: A Review(2018) STIVAL, Larissa R.; FIGUEIREDO, Marisa N.; SANTHIAGO, Marcony R.PURPOSE: To provide an overview of the efficacy andsafety of available presbyopic excimer laser ablation profiles. METHODS: Literature review. RESULTS: Monovision with excimer laser traditionally applies near correction to the non-dominant eye. Different excimer laser presbyopic approaches include the increase in depth of focus, through the controlled change of spherical aberration or asphericity, or multifocal ablation patterns with central or peripheral near vision zones. The studies investigating different excimer laser ablation patterns applied in previously myopic eyes revealed high levels of efficacy with all ablation profiles (between 68% and 99% achieving binocular uncorrected distance visual acuity [UDVA] of 20/25 or better, and between 70% and 100% achieving uncorrected near visual acuity [UNVA] presenting J3 or better). In hypermetropic eyes, most of the studies revealed high levels of efficacy with different platforms (between 78% and 100% achieving binocular UDVA of 20/25 or better and between 70% and 100% achieving UNVA presenting J3 or better). Loss of two or more lines of corrected distance visual acuity varied between 0% and 10% in the myopic eyes and between 0% and 14% in the hyperopic eyes. CONCLUSIONS: There is evidence that excimer laser presbyopic strategies accomplish spectacle independence at reasonable levels. There are reliable and safe options for both myopic and hyperopic eyes with satisfactory outcomes regarding near and distance vision.