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- ItemAcesso aberto (Open Access)Aplicação de fórmula corretiva nas alterações da pressão intraocular dos pacientes submetidos a LASIK(Conselho Brasileiro de Oftalmologia, 2011-04-01) Silva, Thiago George Cabral; Polido, Júlia Gomes Fernandes; Pinheiro, Maurício Vieira; Silva, André Luís De Freitas; Goldbach, Laerte; Mascaro, Vera Lúcia Degaspare Monte [UNIFESP]; Serracarbassa, Pedro Durães; Araújo, Maria Emília Xavier Dos Santos [UNIFESP]; Hospital do Servidor Público Estadual de São Paulo; Hospital do Servidor Público Estadual de São Paulo - HSPE; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)PURPOSE: To compare the intraocular pressure (IOP) pre and post LASIK, correlating it to changes in central corneal thickness (CCT) and average simulated keratometry (K), as well as verifying the results of a corrective formula previously proposed. METHODS: Longitudinal prospective study conducted in outpatients that underwent to LASIK. Patients underwent complete ophthalmic examination, previously and 2 months after the surgery. Intraocular pressure was evaluated with Goldmann applanation tonometer between 9 am and 11 am, average simulated keratometry was evaluated using corneal topography and central corneal thickness was measured with ultrasound pachymetry, been considered the average of three measurements. Two patients were excluded due to surgery or eye disease, and previous use of topical steroids over the past three months. The surgeries were performed according to standard procedures. The formula [real IOP = IOP measured + (540 - ECC)/71 + (43 - K)/2.7 + 0.75 mmHg] proposed for correcting intraocular pressure was used. RESULTS: Fifteen eyes of eight patients were evaluated, age ranged from 24 to 46 years (mean: 31.37 ± 7.27). There was a statistically significant difference between the measurements of intraocular pressure, central corneal thickness and average simulated keratometry pre and post-LASIK. (p=0.0001). It was observed that each 1D corrected underestimated the IOP 1.06 ± 0.59 mmHg (0.11 a 1.89 mmHg). The use of the corrective formula lead to 80% of eyes within 2.50 mmHg of preoperative intraocular pressure. Although, the two sets of data are statistically different (p=0.0266). CONCLUSIONS: Post LASIK eyes presented lower intraocular pressure than preoperatively. Intraocular pressure was moderately correlated to central corneal thickness and weakly correlated to average simulated keratometry. With the use of the corrective formula, we were able to determine that 80% were within 2.50 mmHg of the preoperative intraocular pressure.
- ItemAcesso aberto (Open Access)Clinical evaluation of reprocessed blades in LASIK(Conselho Brasileiro de Oftalmologia, 2008-04-01) Mallmann, Felipe [UNIFESP]; Murata, Celina [UNIFESP]; Yamazaki, Ester Sakae [UNIFESP]; Campos, Mauro Silveira de Queiroz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)PURPOSE: To evaluate outcome and complications in LASIK with reprocessed blades. METHODS: Retrospective analysis of patients' charts submitted to complete custom LASIK from January 2004 to June 2005. Inclusion criteria comprised surgical description of blade use and minimum follow-up of 1 month. The blade was reprocessed following a clinic protocol, from 1 to 3 times (reprocessed group) and results compared with patients that underwent LASIK with first-use blades (first-use group). RESULTS: Two hundred fifty-one eyes of 135 patients were analyzed (spherical equivalent of -3.69 (D). There was no statistical differences between first-use group and reprocessed blade group regarding intraoperative (5.5% vs 8.8%), early (50.5% vs 49.5%) and late complications (33% vs 27.5%), respectively. Uncorrected visual acuity > 20/20 (68.1% vs 66.9%), aberrometry analysis (total RMS: 0.62 vs 0.64 µm) and safety (85.7% vs 83.1%) were similar between groups (p>0.05). CONCLUSION: Reprocessed blades following rigid sterilization protocol may have similar outcomes and complications rates in LASIK surgery compared to first-use blades.
- ItemAcesso aberto (Open Access)Interchangeability between Placido disc and Scheimpflug system: quantitative and qualitative analysis(Conselho Brasileiro de Oftalmologia, 2010-08-01) Stefano, Vinícius Silbiger de [UNIFESP]; Melo Junior, Luiz Alberto Soares [UNIFESP]; Mallmann, Felipe [UNIFESP]; Schor, Paulo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)PURPOSE: Many systems try to replace Placido disc-based topographers, such as those based in Scheimpflug principles. The purpose of this study is to check if they are interchangeable. METHODS: Quantitative analysis evaluated data obtained from EyeSys and Pentacam, i.e. simulated keratometric values, in addition to flattest and steepest keratometric values. Sixty-three maps from each device (EyeSys scale=0.5 D; Pentacam scale= 0.25 D) were used for the comparison. Qualitative analysis selected 10 EyeSys and 15 Pentacam topographies used in the quantitative evaluation. Aspheric, keratoconus suspects (KS) and established keratoconus corneas were included. Four groups (children [CH], non-physicians adults [AD], residents in ophthalmology [OP] and refractive surgeons [RS]) were asked to match the topographies belonging to the same eye. RESULTS: Analysis showed that the parameters are correlated; however they are not clinically similar. In the qualitative analysis, the percent of correct matches increased when KS was removed. CH group was statistically different from every group in these comparisons. When only KS was considered, CH vs. OP, CH vs. RS and AD vs. RS remained statistically different. AD vs. OP showed no relevant difference in any comparison. CONCLUSIONS: The systems are not fully interchangeable, yet they are correlated. Practitioners who are adapting to Pentacam should use the 0.25 D scale maps and transform formulas that use EyeSys parameters. Only with persistent training may the topographies be properly matched; KS corneas are more difficult to be correctly paired.
- ItemAcesso aberto (Open Access)Intrastromal crosslinking in post-LASIK ectasia(Conselho Brasileiro de Oftalmologia, 2014-06-01) Moscovici, Bernardo Kaplan [UNIFESP]; Campos, Mauro Silveira de Queiroz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Descrevemos um caso de ectasia de córnea precoce após cirurgia de LASIK, detectado no primeiro semestre pós-operatório. Nós optamos tratar este paciente com crosslinking embaixo do flap , sem desepitelização com bons resultados. A paciente permaneceu sem progressão da ectasia até o momento atual, dois anos após o procedimento.
- ItemAcesso aberto (Open Access)ORA waveform-derived biomechanical parameters to distinguish normal from keratoconic eyes(Conselho Brasileiro de Oftalmologia, 2013-04-01) Luz, Allan [UNIFESP]; Fontes, Bruno Machado [UNIFESP]; Lopes, Bernardo; Ramos, Isaac; Schor, Paulo [UNIFESP]; Ambrósio Jr., Renato [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Hospital de Olhos de Sergipe; Instituto de Olhos Renato AmbrósioPURPOSE: To evaluate the ability of the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments, Buffalo, NY) to distinguish between normal and keratoconic eyes, by comparing pressure and waveform signal-derived parameters. METHODS: This retrospective comparative case series study included 112 patients with normal corneas and 41 patients with bilateral keratoconic eyes. One eye from each subject was randomly selected for analysis. Keratoconus diagnosis was based on clinical examinations, including Placido disk-based corneal topography and rotating Scheimpflug corneal tomography. Data from the ORA best waveform score (WS) measurements were extracted using ORA software. Corneal hysteresis (CH), corneal resistance factor (CRF), Goldman-correlated intraocular pressure (IOPg), cornea-compensated intraocular pressure (IOPcc), and 37 parameters derived from the waveform signal were analyzed. Differences in the distributions among the groups were assessed using the Mann-Whitney test. Receiver operating characteristic (ROC) curves were calculated. RESULTS: Statistically significant differences between keratoconic and normal eyes were found in all parameters (p<0.05) except IOPcc and W1. The area under the ROC curve (AUROC) was greater than 0.85 for 11 parameters, including CH (0.852) and CRF (0.895). The parameters related to the area under the waveform peak during the second and first applanations (p2area and p1area) had the best performances, with AUROCs of 0.939 and 0.929, respectively. The AUROCs for CRF, p2area, and p1area were significantly greater than that for CH. CONCLUSION: There are significant differences in biomechanical metrics between normal and keratoconic eyes. Compared with the pressure-derived parameters, corneal hysteresis and corneal resistance factor, novel waveform-derived ORA parameters provide better identification of keratoconus.
- ItemSomente MetadadadosResultados preliminares de um algoritmo para ablação de lente de contato personalizada(Consel Brasil Oftalmologia, 2009-03-01) Matos, Luciana de [UNIFESP]; Carvalho, Luis Alberto Vieira de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Purpose: To develop a computer simulation for customized soft contact lenses in order to correct aberrations of higher order. Methods: Using real data from a patient diagnosed with keratoconus, which were measured using a Hartmann-Shack wavefront sensor, the thickness of the contact lenses that compensate these aberrations as well the numbers of pulses required to ablate the lenses were specifically determined for the patient. Results: The maps of correction are presented and the numbers of pulses are calculated, using a 0.5 mm beam width and a 0.3 mu m ablation depth. Conclusions: The results shown here are promising, but they should be improved so that the ablation in actual physical systems can reach the desired accuracy.
- ItemAcesso aberto (Open Access)Resultados preliminares de um sistema computadorizado e estereoscópico para pupilometria in vivo(Conselho Brasileiro de Oftalmologia, 2008-12-01) Carvalho, Luis Alberto Vieira de [UNIFESP]; Paranhos Junior, Augusto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Instituto Israelita de Ensino e Pesquisa Albert Einstein Pesquisa ClínicaPURPOSE: We developed a digital system with accommodation capacities for measurement of the diameter and shape of the in vivo pupil for 10 different levels of illumination intensity, varying from mesopic to photopic. METHODS: An optical system for conjugating images from an infrared and white light illuminated pupil was designed and mounted using an ophthalmoscope helmet and a typical diving mask as support for a high-resolution and sensitivity CCD. Using an IBM compatible computer sequences of video in AVI format were digitized for several seconds at a mean rate of 30 Hz. Algorithms using principles of image processing were implemented for detection of the pupil edges. RESULTS: We present preliminary results of this system for a voluntary patient. Data for the horizontal (x) and vertical (y) central position and for the diameter of the pupil were then exported to files that could be read by typical spread sheet programs (Excel). CONCLUSIONS: In this manner, precise data can be obtained stereoscopically (for both pupils at the same time) for any patient, given that the accommodation process is guaranteed by using a white LED virtual mire located 6 meters from the patient's eye. An electronic board precisely controls the level of illumination. We believe here developed instrument may be useful in certain ophthalmic practices where precise pupil geometric data are needed.
- ItemAcesso aberto (Open Access)Wavefront-guided refractive surgery results of training-surgeons(Conselho Brasileiro de Oftalmologia, 2010-08-01) Stillitano, Iane [UNIFESP]; Yamazaki, Ester [UNIFESP]; Melo Jr, Luiz Alberto [UNIFESP]; Bottos, Juliana [UNIFESP]; Campos, Mauro Silveira de Queiroz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)PURPOSE: To assess clinical outcomes and changes on higher-order aberrations (HOA) after wavefront-guided laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) for correction of myopia and myopic astigmatism performed by training-surgeons. METHODS: One hundred and seventy patients had customized LASIK (207 eyes) and PRK (103 eyes) performed by surgeons in-training using the LADARVision 4000 (Alcon, Fort Worth, TX). Preoperative and 1, 3, 6 and 12 months postoperative data of spherical equivalent (SE), best spectacle-corrected visual acuity (BSCVA) and uncorrected visual acuity (UCVA) were analysed. Wavefront changes were determined using the LADARWave Hartmann-Shack wavefront aberrometer and the pupil size was scaled for 6.5 mm. RESULTS: The mean SE in the LASIK group was -3.04 ±1.07 D and in the PRK group was -1.60 ± 0.59 D. At 1-year follow-up, (80.6%) (LASIK) and (66.7%) (PRK) were within ± 0.50 D of the intended refraction. The UCVA was 20/20 or better in (58.1%) (LASIK) and (66.7%) (PRK) of the operated eyes. A statistically significant positive correlation was found between achieved versus attempted refractive correction in both groups: LASIK (r=0.975, P<0.0005) and PRK (r=0.943, P<0.005). The higher-order aberrations (HO) RMS and coma did not changed signicantly in the PRK group between preoperative and 1-year follow-up. In the LASIK group the HO RMS and coma changed between preoperative and 1-month postoperative but remained statistically unchanged during 1-year follow-up. The spherical aberration showed statistically significant changes in both groups. CONCLUSIONS: Wavefront-guided LASIK and photorefractive keratectomy performed by training-surgeons were found to be similarly effective, predictable and stable.