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A Ferreras

Publications and source records attributed to A Ferreras.

8 recordsLinked to original sources
PubMed2006

[Sector-based analysis of the distribution of the neuroretinal rim by confocal scanning laser in the diagnosis of glaucoma].

PURPOSE: To evaluate the diagnostic ability of the Moorfields regression analysis (MRA; neuroretinal rim sector-based analysis) by means of confocal scanning laser. METHODS: 200 eyes were included in this study: 101 normal subjects and 99 glaucoma patients (standard automated perimetry with glaucomatous defects -MD or CPSD with p<0.02 or a cluster of three or more points with p<0.05 or a cluster of two or more points with p<0.01 or abnormal Glaucoma Hemifield Test). All subjects underwent a full ophthalmic evaluation, visual field evaluation by means of a Humphrey Field Analyzer, 24-2 full threshold strategy, and optic disc topography by Heidelberg retina tomograph (HRT-II). The outcome parameters were sensitivity and specificity of the MRA for each sector. RESULTS: The highest sensitivity in detecting structural defects based on MRA (p<0.05) was observed in the nasal-superior sector (48%) and nasal-inferior sector (45%); however the highest specificity was found in the temporal-superior (98%) and inferior (98%) sectors. The highest sensitivity for MRA (p<0.01) was found in the temporal-inferior sector (31%) and nasal-superior sector (30%) while the temporal-superior and inferior-sectors showed the highest specificity (100%). The diagnosis of glaucoma based on the presence of any sector alteration showed sensitivity figures of 67% with p<0.05 and 46% with p<0.01 and specificity values of 84% with p<0.05 and 96% with p<0.01. CONCLUSIONS: The analysis of the distribution of the neuroretinal rim by means of HRT-II contributes effectively to the diagnosis of glaucoma based on perimetry in a sample derived from a Spanish population.

Adult↗
PubMed2006

[Reproducibility of optic nerve head and retinal nerve fiber layer thickness measurements using optical coherence tomography].

PURPOSE: To evaluate the reproducibility of repeated quantitative measurements of optic nerve head topography and retinal nerve fiber layer thickness. METHODS: This study included 32 normal subjects, 41 patients with ocular hypertension and 33 patients with glaucoma. The study groups were defined by the intraocular pressure levels, optic disc stereo-photographs and perimetric performance. Optic disc and retinal nerve fiber layer assessments were performed by ocular coherence tomography (OCT III, Zeiss Instruments). OCT examination was repeated three times in each subject and the coefficient of variability was elaborated for each parameter and group of the study, and compared among them. RESULTS: The average retinal nerve fiber layer thickness measurement showed the best reproducibility figures with a coefficient of variability of 5.9%. The inferior quadrant and the 10, 6 and 7 clock-hours (coefficients of variability 6.3%, 7.4%, 7.5% and 8.6% respectively) showed higher reproducibility. The optic nerve head assessment showed the best reproducibility for the cup-to-disc ratios (vertical, horizontal and area ratios), with a coefficient of variability of 5.0%, 4.2% and 6.6% respectively. Although differences among groups were barely statistically significant, the glaucoma group showed coefficients of variability higher than the other two groups. CONCLUSIONS: Optic nerve head analysis and retinal nerve fiber layer thickness can be reproducibly assessed by OCT. The reproducibility of the device supports its potential use for ocular hypertension follow-up, although its use in glaucoma patients may present difficulties in some parameters.

Female↗
PubMed2006

[Diagnostic ability of stratus optical coherence tomography (OCT) in pre-perimetric glaucoma diagnosis].

OBJECTIVE: To compare retinal nerve fiber layer (RNFL) measurements performed with Stratus OCT 3000 in normal, ocular hypertensive, pre-perimetric and glaucomatous eyes. METHODS: 98 normal subjects, 156 ocular hypertensives with short-wavelength automated perimetry (SWAP), 21 ocular hypertensives with altered SWAP (pre-perimetric glaucoma) and 66 glaucomatous eyes were included in the study. Diagnostic groups were classified based on intraocular pressure, optic nerve head appearance, achromatic automatic perimetry and SWAP. RNFL parameters were obtained using a Stratus OCT 3000 (Humphrey Zeiss instruments). RNFL measurements were compared among the groups. RESULTS: RNFL average thickness, superior, inferior and nasal quadrant thickness, and each 12 clock-hour positions except for H9, H10 and H11 showed significant differences between glaucomatous and pre-perimetric glaucoma eyes. RNFL average thickness, inferior quadrant and H10 clock-hour position showed significant differences between normal and ocular hypertensive subjects. Pre-perimetric glaucomas and ocular hypertensives showed differences in H11 clock-hour position exclusively. CONCLUSION: RNFL measurements performed using Stratus OCT showed differences between the study groups. OCT may be as useful as SWAP in early glaucoma diagnosis.

Female↗
PubMed2006

[Diagnostic usefulness of optical coherence tomography (OCT), scanning laser tomography (HRT-II) and laser polarimetry (GDx) in open-angle glaucoma].

PURPOSE: To evaluate the diagnostic ability of three digital imaging technologies (HRT-II, OCT and GDx VCC) in detecting glaucomatous damage. METHODS: A total of 427 eyes from 427 subjects were included in this cross-sectional study. Each subject was classified as healthy, ocular hypertensive or glaucomatous, according to intraocular pressure levels, standard automated perimetry and optic disc morphology. All of them underwent examination by means of HRT, OCT and GDx VCC. Receiver operating characteristic (ROC) curves were plotted and sensitivities at fixed specificities (85% and 95%) were calculated for each parameter assessed. RESULTS: The parameters with the higher diagnostic ability were: FSM discriminant function from HRT-II (AUC=0.899), retinal nerve fiber layer average thickness from OCT (AUC=0.929) and NFI from GDx VCC (AUC=0.879), with no statistically significant differences between them. CONCLUSION: The HRT-II, OCT and GDx VCC provide measurements of the retinal nerve fiber layer and the optic nerve head with high discriminating ability in open-angle glaucoma.

Aged↗
PubMed2003

[Benefit of scanning laser ophthalmoscopy for detecting retinal nerve fiber layer defects in patients with intraocular hypertension].

PURPOSE: To compare the ability to identify RNFL alterations between standard images and SLO images in a group of patients suffering from ocular hypertension. METHODS: We evaluated RNFL in sixty patients with ocular hypertension and with normal perimetry, by using standard photography and SLO. Two different independent observers evaluated the images on two different ocassions. RESULTS: We studied 118 eyes, twelve eyes were rejected because of the low quality of the images. Four cases of diffuse atrophy and five patients with wedge shaped defects were observed using both methods. Statistical analysis showed no differences between both exploration techniques or between observers. CONCLUSIONS: RNFL study with SLO seems to be at least as reliable as standard photography as a method to evaluate RNFL defects. SLO has also proved to be much easier, and faster than traditional methods.

Female↗
PubMedDate not supplied

Glaucomatous damage patterns by short-wavelength automated perimetry (SWAP) in glaucoma suspects.

PURPOSE: To determine the glaucomatous visual field damage patterns by short-wavelength automated perimetry (SWAP) in glaucoma suspects, and to compare the frequency of diffuse visual field losses and localized defects. METHODS: 157 eyes of 157 ocular hypertensive subjects who met the selection criteria (intraocular pressure greater than 21 mm Hg and normal standard visual fields) were studied. SWAP was done with a modified Humphrey Field Analyzer. Total (TD) and Pattern Deviation (PD) probability maps were calculated for SWAP. The frequency of abnormlities in the TD and PD were determined, analyzing the visual field loss components. RESULTS: The involvement of the test points was more frequent on the TD plots than on the PD plots for all levels of defects (p< 0.001). The glaucomatous defects also showed certain topographical distribution. CONCLUSIONS: A diffuse sensitivity component of visual field loss was found at all SWAP defect depths in glaucoma suspects.

Adult↗
PubMedDate not supplied

An in vitro system from Plasmodium falciparum active in endogenous mRNA translation.

An in vitro translation system has been prepared from Plasmodium falciparum by saponin lysis of infected-erythrocytes to free parasites which were homogeneized with glass beads, centrifuged to obtain a S-30 fraction followed by Sephadex G-25 gel filtration. This treatment produced a system with very low contamination of host proteins (<1%). The system, optimized for Mg2+ and K+, translates endogenous mRNA and is active for 80 min which suggests that their protein factors and mRNA are quite stable.

Animals↗