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
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- 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.
- Association Between the Percent Tissue Altered and Post-Laser In Situ Keratomileusis Ectasia in Eyes With Normal Preoperative Topography(2014) SANTHIAGO, Marcony R.; SMADJA, David; GOMES, Beatriz F.; MELLO, Glauco R.; MONTEIRO, Mario L. R.; WILSON, Steven E.; RANDLEMAN, J. BradleyPURPOSE: To investigate the association of a novel metric, percent tissue altered, with the occurrence of ectasia after laser in situ keratomileusis (LASIK) in eyes with normal corneal topography and to compare this metric with other recognized risk factors. DESIGN: Retrospective case-control study. METHODS: The study included 30 eyes from 16 patients with bilateral normal preoperative Placido-based corneal topography that developed ectasia after LASIK (ectasia group) and 174 eyes from 88 consecutive patients with uncomplicated LASIK and at least 3 years of postoperative follow-up. The following metrics were evaluated: age, preoperative central corneal thickness, residual stromal bed, Ectasia Risk Score System scores, and percent tissue altered, derived from [PTA = (FT + AD)/CCT], where FT = flap thickness, AD = ablation depth, and CCT = preoperative central corneal thickness. RESULTS: In the ectasia group, percent tissue altered >= 40 was the most prevalent factor (97%), followed by age < 30 years (63%), residual stromal bed <= 300 mu m (57%), and ectasia risk score >= 3 (43%) (P < .001 for all). Percent tissue altered >= 40 had the highest odds ratio (223), followed by residual stromal bed <= 300 mu m (74) and ectasia risk score >= 4 (8). Stepwise logistic regression revealed percent tissue altered >= 40 as the single most significant independent variable (P < .0001). CONCLUSIONS: Percent tissue altered at the time of LASIK was significantly associated with the development of ectasia in eyes with normal preoperative topography and was a more robust indicator of risk than all other variables in this patient population.
- The Corneal Basement Membranes and Stromal Fibrosis(2018) MEDEIROS, Carla S.; MARINO, Gustavo K.; SANTHIAGO, Marcony R.; WILSON, Steven E.PURPOSE. The purpose of this review was to provide detailed insights into the pathophysiology of myofibroblast-mediated fibrosis (scarring or late haze) after corneal injury, surgery, or infection. METHOD. Literature review. RESULTS. The epithelium and epithelial basement membrane (EBM) and/or endothelium and Descemet's basement membrane (BM) are commonly disrupted after corneal injuries, surgeries, and infections. Regeneration of these critical regulatory structures relies on the coordinated production of BM components, including laminins, nidogens, perlecan, and collagen type IV by epithelial, endothelial, and keratocyte cells. Whether a cornea, or an area in the cornea, heals with transparency or fibrosis may be determined by whether there is injury to one or both corneal basement membranes (EBM and/or Descemet's BM) and delayed or defective regeneration or replacement of the BM. These opaque myofibroblasts, and the disordered extracellular matrix these cells produce, persist in the stroma until the EBM and/or Descemet's BM is regenerated or replaced. CONCLUSIONS. Corneal stromal fibrosis (also termed ""stromal scarring'' or ""late haze'') occurs as a consequence of BM injury and defective regeneration in both the anterior (EBM) and posterior (Descemet's BM) cornea. The resolution of fibrosis and return of stromal transparency depends on reestablished BM structure and function. It is hypothesized that defective regeneration of the EBM or Descemet's BM allows key profibrotic growth factors, including transforming growth factor beta-1 (TGF-beta 1) and TGF-beta 2, to penetrate the stroma at sustained levels necessary to drive the development and maintenance of mature opacity-producing myofibroblasts from myofibroblast precursors cells, and studies suggest that perlecan and collagen type IV are the critical components in EBM and Descemet's BM that bind TGF-beta 1, TGF-beta 2, platelet-derived growth factor, and possibly other growth factors, and regulate their bioavailability and function during homeostasis and corneal wound healing.
- Relative contribution of flap thickness and ablation depth to the percentage of tissue altered in ectasia after laser in situ keratomileusis(2015) SANTHIAGO, Marcony R.; SMAJDA, David; WILSON, Steven E.; RANDLEMAN, J. BradleyPURPOSE: To evaluate the contribution of flap thickness and ablation depth to the percentage of tissue altered (PTA) (flap thickness plus ablation depth divided by central corneal thickness) in determining the risk for ectasia after laser in situ keratomileusis (LASIK). SETTING: University of Sao Paulo, Sao Paulo, Brazil; Cleveland Clinic, Cleveland, Ohio, and Emory Vision at Emory University, Atlanta, Georgia, USA. DESIGN: Retrospective comparative study. METHODS: The study included 1 group of eyes with bilateral normal preoperative topography that developed ectasia after LASIK (ectasia group) and 2 control groups of eyes that did not develop ectasia after LASIK, 1 with 40% or more of tissue altered (high-PTA group) and 1 with flaps 120 mu m or thicker (thick-flap group). RESULTS: The 29 eyes (16 patients) in the ectasia group had thicker flaps (146 mu m) than the 24 eyes (20 patients) in the high-PTA group (118 mu m) and derived a higher portion of PTA from flap thickness. The ectasia group had a higher PTA (45%) than the 100 eyes (50 patients) in the thick-flap group (34%) and greater ablation depths (94 mu m versus 43 mu m) and derived a higher portion of the PTA from ablation depth. CONCLUSIONS: Flap thickness had more impact than ablation depth; however, thicker flaps were insufficient to create ectasia unless coupled with greater ablation depths and thus a high PTA. This percentage was a more significant factor than the variables it comprised. (C) 2015 ASCRS and ESCRS
- 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.
- Role of Percent Tissue Altered on Ectasia After LASIK in Eyes With Suspicious Topography(2015) SANTHIAGO, Marcony R.; SMADJA, David; WILSON, Steven E.; KRUEGER, Ronald R.; MONTEIRO, Mario L. R.; RANDLEMAN, J. BradleyPURPOSE: To investigate the association of the percent tissue altered (PTA) with the occurrence of ectasia after LASIK in eyes with suspicious preoperative corneal topography. METHODS: This retrospective comparative case-control study compared associations of reported ectasia risk factors in 129 eyes, including 57 eyes with suspicious preoperative Placido-based corneal topography that developed ectasia after LASIK (suspect ectasia group), 32 eyes with suspicious topography that remained stable for at least 3 years after LASIK (suspect control group), and 30 eyes that developed ectasia with bilateral normal topography (normal topography ectasia group). Groups were subdivided based on topographic asymmetry into high-or low-suspect groups. The PTA, preoperative central corneal thickness (CCT), residual stromal bed (RSB), and age (years) were evaluated in univariate and multivariate analyses. RESULTS: Average PTA values for normal topography ectasia (45), low-suspect ectasia (39), high-suspect ectasia (36), low-suspect control (32), and high-suspect control (29) were significantly different from one another in all comparisons (P < .003) except high-and low-suspect ectasia groups (P = .033), and presented the highest discriminative capability of all variables evaluated. Age was only significantly different between the high-suspect ectasia and normal topography ectasia groups, and CCT was not significantly different between any groups. Stepwise logistic regression revealed the PTA as the most significant independent variable (P < .0001), with RSB the next most significant parameter. CONCLUSIONS: There remains a significant correlation between PTA values and ectasia risk after LASIK, even in eyes with suspicious corneal topography. Less tissue alteration, or a lower PTA value, was necessary to induce ectasia in eyes with more remarkable signs of topographic abnormality, and PTA provided better discriminative capabilities than RSB for all study populations.
- Corneal Ectasia Risk And Percentage Tissue Altered In Myopic Patients Presenting For Refractive Surgery(2019) ONG, Hon Shing; FAROOK, Mohamed; TAN, Benjamin Boon Chuan; WILLIAMS, Geraint P.; SANTHIAGO, Marcony R.; MEHTA, Jodhbir S.Purpose: A percentage tissue altered (PTA) score of >= 40% has been advocated as an independent indicator of post-operative ectasia risk following laser in-situ keratomileusis (LASIK). This study was performed to test the hypothesis that refractive procedures, such as laser-assisted subepithelial keratectomy (LASEK) or small incision lenticule extraction (SMILE), may alter the range of PTA, within which refractive corneal surgery can be safely performed. Setting: Refractive department, tertiary ophthalmic hospital. Design: Retrospective observational study. Methods: Review of case notes was performed for patients who presented for refractive surgeries, other than LASIK. To determine the risk of corneal ectasia for each patient prior to refractive surgery, we estimated what each patient's PTA would have been if they had undergone LASIK. The Randleman Ectasia Risk Score System (ERSS) was also calculated. Results: 114 eyes (66 patients) were included. 94 eyes underwent SMILE. 20 eyes underwent LASEK. A significant proportion of eyes had PTA >= 40% - SMILE eyes: up to 31.9%, LASEK eyes: up to 60.0% (at presumed LASIK flap of 120 mu m). The maximum calculated PTA was up to 47.9% in the SMILE group and up to 51.5% in the LASEK group. Using ERSS, 12.8-16% of SMILE eyes and 15.0-80.0% of LASEK eyes would have been considered to have moderate-to-high ectasia risk. No post-surgical ectasia was observed at 3 years. Conclusion: SMILE and LASEK alter the range of PTA, within which corneal refractive surgery may be performed with a lower risk of developing post-operative corneal ectasia; a safe PTA threshold needs to be determined for these procedures before recommendations for clinical practice can be made.
- 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.
- Distinguishing Highly Asymmetric Keratoconus Eyes Using Combined Scheimpflug and Spectral-Domain OCT Analysis(2018) HWANG, Eric S.; PEREZ-STRAZIOTA, Claudia E.; KIM, Sang Woo; SANTHIAGO, Marcony R.; RANDLEMAN, J. BradleyPurpose: To determine optimal objective, machine-derived variables and variable combinations from Scheimpflug and spectral-domain (SD) OCT imaging to distinguish the clinically unaffected eye in patients with asymmetric keratoconus (AKC) from a normal control population. Design: Retrospective case-control study. Participants: Thirty clinically unaffected eyes with no physical findings on slit-lamp examination, no definitive abnormalities on corneal imaging, and corrected distance acuity of 20/20 or better from 30 patients with highly AKC eyes and 60 eyes from 60 normal control patients who had undergone uneventful LASIK with at least 2 years of stable follow-up (controls). Methods: Scheimpflug and SD OCT imaging were obtained in all eyes, and receiver operating characteristic (ROC) curves were generated to determine area under the curve (AUC), sensitivity, and specificity for each machine-derived variable and variable combination. Main Outcome Measures: Distinguishing AKC eyes from controls as determined by AUC, sensitivity, and specificity. Results: No individual machine-derived metric from Scheimpflug or SD OCT technology yielded an AUC higher than 0.75. Combining 5 Scheimpflug metrics (index height decentration [IHD], index vertical asymmetry [IVA], pachymetry apex, inferior-superior value, and Ambrosio's Relational Thickness Maximum [ARTmax]) yielded the best Scheimpflug results (AUC 0.86, sensitivity 83%, specificity 83%). Combining 11 SD OCT thickness metrics (minimum-median, temporal outer, superior nasal outer, minimum, epithelium minimum-maximum, epithelial standard deviation, superior inner, superior outer, superior temporal outer, superior nasal inner, central) yielded the best SD OCT results (AUC 0.96, sensitivity 89%, specificity 89%). Combining 13 total Scheimpflug/SD OCT metrics yielded the best results overall (AUC 1.0, sensitivity 100%, specificity 100%). The most impactful variables in combined models included epithelial thickness variability and total focal corneal thickness variability from SD OCT and anterior curvature and topometric indices from Scheimpflug technology. No posterior corneal metrics were impactful in modeling. Conclusions: Individual machine-derived metrics from Scheimpflug and SD OCT imaging poorly distinguished normal eyes from minimally affected eyes from patients with highly AKC. Combined SD OCT metrics performed better than combined Scheimpflug metrics. Combining anterior curvature and asymmetry indices from Scheimpflug with regional total thickness and epithelial thickness variability metrics from SD OCT clearly distinguished the 2 populations. Posterior corneal indices were not useful in distinguishing populations. (C) 2018 by the American Academy of Ophthalmology
- 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.