MARCONY RODRIGUES DE SANTHIAGO
Projetos de Pesquisa
Unidades Organizacionais
LIM/33 - Laboratório de Oftalmologia, Hospital das Clínicas, Faculdade de Medicina
5 resultados
Resultados de Busca
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- 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.
- 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
- 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.
- Intense Early Flattening After Corneal Collagen Cross-linking(2015) SANTHIAGO, Marcony R.; GIACOMIN, Natalia T.; MEDEIROS, Carla S.; SMADJA, David; BECHARA, Samir J.PURPOSE: To report two cases of significant flattening after corneal cross-linking (CXL) for keratoconus and discuss its potential explanations and implications. METHODS: Observational case report. RESULTS: One year after standard CXL protocol (3 mW/cm(2) for 30 minutes and total energy of 5.4 J/cm(2)), a 28-year-old woman presented a flattening of greater than 14 diopters and a 14-year-old boy presented a flattening of 7 diopters. CONCLUSIONS: Although rare, a significant flattening effect may occur during the first year after CXL, probably related to intense wound healing, increase in corneal elasticity, CXL effective depth, and central cone location. These cases suggest the necessity of a patient-specific approach and a better understanding regarding the actual mechanism behind its potent effect.
conferenceObject Role of Percentage of Tissue Altered (PTA) as a risk factor in eyes with Normal preoperative topography that developed Ectasia after LASIK(2014) SANTHIAGO, Marcony Rodrigues; SMADJA, David; GOMES, Beatriz; WILSON, Steven E.; MELLO, Glauco; MONTEIRO, Mario L. R.; RANDLEMAN, James Bradley