Biomedical subjects

Luiz A S Melo

Publications and source records attributed to Luiz A S Melo.

5 recordsLinked to original sources

PubMed2006

Retinal assessment using optical coherence tomography.

Over the 15 years since the original description, optical coherence tomography (OCT) has become one of the key diagnostic technologies in the ophthalmic subspecialty areas of retinal diseases and glaucoma. The reason for the widespread adoption of this technology originates from at least two properties of the OCT results: on the one hand, the results are accessible to the non-specialist where microscopic retinal abnormalities are grossly and easily noticeable; on the other hand, results are reproducible and exceedingly quantitative in the hands of the specialist. However, as in any other imaging technique in ophthalmology, some artifacts are expected to occur. Understanding of the basic principles of image acquisition and data processing as well as recognition of OCT limitations are crucial issues to using this equipment with cleverness. Herein, we took a brief look in the past of OCT and have explained the key basic physical principles of this imaging technology. In addition, each of the several steps encompassing a third generation OCT evaluation of retinal tissues has been addressed in details. A comprehensive explanation about next generation OCT systems has also been provided and, to conclude, we have commented on the future directions of this exceptional technique.

Anatomy, Cross-Sectional↗

PubMed2006

Comparison of optic disk and retinal nerve fiber layer thickness in nonglaucomatous and glaucomatous patients with high myopia.

PURPOSE: To assess the optic nerve head (ONH) by optical coherence tomography (OCT), confocal scanning laser ophthalmoscopy (CSLO), and the retinal nerve fiber layer (RNFL) by OCT and scanning laser polarimetry (GDx) in highly myopic subjects. DESIGN: Observational cross-sectional study. METHODS: Thirty-five eyes of highly myopic individuals without glaucoma and 17 eyes of highly myopic patients with glaucoma were included in this study. All patients had myopia higher than 5.0 diopters and ocular axial length higher than 25 mm. In those patients without glaucoma, the intraocular pressure (IOP) was less than 21 mm Hg. RESULTS: Mean (SD) OCT cup-to-disk area ratio was 0.45 (0.30) and 0.58 (0.29) in the nonglaucomatous and glaucomatous subjects, respectively (P = .22); CSLO cup-to-disk area ratio was 0.27 (0.27) and 0.24 (0.23), respectively (P = .75); and OCT-RNFL was 65.2 (26.2) microm and 56.8 (28.6) microm (P = .43). CONCLUSIONS: OCT, CSLO, and GDx are not useful to discriminate nonglaucomatous and glaucomatous subjects that have high myopia.

Adult↗

PubMed2006

Intravitreal bevacizumab for choroidal neovascularization caused by AMD (IBeNA Study): results of a phase 1 dose-escalation study.

PURPOSE: To evaluate the safety of three dose regimens of intravitreal bevacizumab (Avastin; Genentech, Inc., South San Francisco, CA) for the management of choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD). METHODS: This was a prospective, nonrandomized open-label study of 45 patients with AMD and subfoveal CNV. A standardized ophthalmic evaluation was performed at baseline and at weeks 1, 6, and 12 (+/-1) after a single intravitreous injection (1.0, 1.5, or 2.0 mg) of bevacizumab. Main outcomes measures include clinical evidence of toxicity and complications. Changes in best corrected visual acuity (BCVA) and lesion characteristics-macular morphology were also evaluated. RESULTS: The most common adverse events were conjunctival hyperemia and subconjunctival hemorrhage at the injection site. Mean BCVA improved from baseline throughout the study (P < 0.001; ANOVA with Geisser-Greenhouse correction). Compared with baseline, BCVA was improved at week 1 (P = 0.001), week 6 (P < 0.001), and week 12 (P = 0.001; Dunnett test). At week 12, the lesion area and CNV area were stable or decreased in 79.1% (34/43) and in 74.4% (32/43) of patients, respectively, with no deterioration of macular architecture observed in 83.7% (36/43). A dose-related change in BCVA (in Early Treatment Diabetic Retinopathy Study [ETDRS] lines) was observed at week 12 (1.0 mg [+0.3 line]; 1.5 mg [+0.6 line]; and 2.0 mg [+1.0 line]; P = 0.02; nonparametric test for ordered groups). CONCLUSIONS: A single intravitreal bevacizumab injection was well tolerated and, except for minor transient local adverse events, no other adverse events were observed. In the short-term, treatment was associated with vision stabilization or improvement and no unfavorable neovascular lesion-macular changes in most patients.

Aged↗

PubMed2005

Comparison of intravitreal versus posterior sub-Tenon's capsule injection of triamcinolone acetonide for diffuse diabetic macular edema.

PURPOSE: To compare the safety and efficacy of intravitreal versus posterior Sub-Tenon's capsule injection of triamcinolone acetonide for diffuse diabetic macular edema. DESIGN: Prospective, double-masked, randomized controlled trial. PARTICIPANTS: Twelve patients (24 eyes) with bilateral diffuse diabetic macular edema. INTERVENTION: One eye of each patient was randomly assigned to receive a single 4-mg triamcinolone acetonide intravitreal injection and the fellow eye to receive a 40-mg triamcinolone acetonide posterior Sub-Tenon's capsule injection. MAIN OUTCOME MEASURES: Changes in visual acuity and central macular thickness obtained using optical coherence tomography were measured during a 6-month follow-up. Potential treatment complications were monitored, including increases in intraocular pressure (IOP) and cataract progression. RESULTS: Both intravitreal and Sub-Tenon's capsule injections of triamcinolone acetonide resulted in significant but transient improvements in central macular thickness. The mean (+/-standard deviation [SD]) central macular thickness in eyes with intravitreal injection was significantly thinner than in the Sub-Tenon's capsule-injected eyes at 1 month (226.8+/-41.7 microm and 431.5+/-165.8 microm, respectively; P = 0.002) and 3 months (242.3 +/- 93.9 microm and 364.7+/-78.2 microm, respectively; P = 0.005) after triamcinolone acetonide injection. The mean visual acuity (logarithm of the minimum angle of resolution) in the intravitreally injected eyes was significantly better than in the Sub-Tenon's capsule-injected eyes at 3 months post injection (0.832+/-0.293 and 1.107+/-0.339, respectively; P = 0.004). Intraocular pressure did not show any significant difference between the 2 forms of triamcinolone acetonide delivery at any follow-up visit, and no eyes had IOPs >25 mmHg. CONCLUSIONS: The findings from our study neither advocate nor support the use of corticosteroids for the treatment of diabetic macular edema, but do imply that both intravitreal and Sub-Tenon's capsule injections of triamcinolone acetonide may be equally tolerated, with short-term performance clearly favoring the intravitreal (4 mg) more than the SBT capsule (40 mg) route for the anatomic and functional aspects of improvement tested in this investigation.

Adult↗

PubMed2004

A single intraoperative sub-Tenon's capsule triamcinolone acetonide injection for the treatment of post-cataract surgery inflammation.

PURPOSE: To compare a single intraoperative sub-Tenon's capsule triamcinolone acetonide injection with steroid drops in the treatment of ocular inflammation after cataract surgery. DESIGN: Randomized, double-masked controlled trial. PARTICIPANTS: A total of 100 patients were randomized prospectively into 2 groups: 50 patients treated with 1% prednisolone eyedrops (control group A) and 50 patients treated with sub-Tenon's capsule triamcinolone (treatment group B). METHODS: All patients underwent phacoemulsification and intraocular posterior lens implantation. After surgery, patients were randomized to receive either (group B) an intraoperative 40 mg triamcinolone acetonide sub-Tenon's capsule injection or (group A) 1% prednisolone acetate eyedrops, according to the following schedule: 1 drop 4 times daily (week 1), 3 times daily (week 2), 2 times daily (week 3), once daily (week 4). To mask the study, group B received vehicle drops administered on a similar schedule, and group A received an intraoperative sub-Tenon's capsule injection of a 1 ml balanced salt solution. MAIN OUTCOME MEASURES: The main outcome measures included inflammation (cell, flare, ciliary flush), intraocular pressure, and lack of response. RESULTS: Triamcinolone was shown to have anti-inflammatory efficacy clinically equivalent to conventional 1% prednisolone eyedrops in reducing intraocular inflammation, as measured by clinical methods. Triamcinolone was found to be as safe as the prednisolone in terms of adverse effects, changes in visual acuity, intraocular pressure, and biomicroscopic and ophthalmoscopic variables. On the third, seventh, fourteenth, and twenty-eighth postoperative days, a significantly lower intraocular pressure (P<0.01) was noted in the triamcinolone group than in the prednisolone group. CONCLUSIONS: A single intraoperative 40-mg triamcinolone acetonide sub-Tenon's capsule injection demonstrated a clinically equivalent therapeutic response and ocular tolerance compared with 1% prednisolone drops in controlling postoperative inflammation after uncomplicated cataract surgery and merits further investigation.

Aged↗