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Biomedical subjects

M Iester

Publications and source records attributed to M Iester.

47 records · Page 3Linked to original sources
PubMed1997

ROC analysis of Heidelberg Retina Tomograph optic disc shape measures in glaucoma.

OBJECTIVE: To determine the capacity of the Heidelberg Retina Tomograph (HRT) optic disc shape measures to detect glaucomatous damage. DESIGN: Prospective study. SETTING: Department of ophthalmology at a university-affiliated hospital in Vancouver. PATIENTS: Ninety-seven consecutive patients from the glaucoma centre and 129 healthy subjects selected from volunteers and employees of the department. One eye of each subject was chosen randomly. OUTCOME MEASURES: Visual fields, as assessed with the Humphrey perimeter, program 30-2, and 12 HRT shape characteristics: disc area, cup area cup/disc area ratio, rim area, cup volume, rim volume, mean cup depth, maximum cup depth, cup shape measure, height variation contour, mean retinal nerve fibre layer thickness and retinal nerve fiber layer cross-section area. ROC (receiver operating characteristic) curves were used to analyse the capacity of each HRT characteristic to detect glaucoma. RESULTS: Statistically significant difference were found between the control and glaucoma groups in age, cup area, cup/disc ratio, rim area, cup volume, rim volume, mean cup depth, cup shape measure, mean retinal nerve fibre layer thickness and retinal nerve fibre layer cross-section area (p < or = 0.003, t-test). The largest (i.e., best) ROC curve area was found for cup shape measure (area = 0.812), rim area (0.809), cup/disc area ratio (0.804) and rim volume (0.768). The mean reference height was 0.31 mm (standard deviation [SD] 0.14 mm) for the control group and 0.29 mm (SD 0.12 mm) for the glaucoma group, a nonsignificant difference. CONCLUSIONS: Cup shape measure was the most predictive HRT shape characteristic.

Adult↗
PubMed1997

A comparison of healthy, ocular hypertensive, and glaucomatous optic disc topographic parameters.

PURPOSE: To compare the optic discs of 62 healthy individuals 68 patients who have ocular hypertension (OH), and 182 patients with primary open-angle glaucoma (132 high-tension glaucoma (HTG) and 50 normal-tension glaucoma (NTG)), and determine whether disc size exerted an influence on the group differentiation. PATIENTS AND METHODS: Standard criteria were used to define glaucoma and normality. Ocular hypertension was defined as having raised intraocular pressure, a normal visual field, and a healthy optic disc/retinal nerve fiber layer (RNFL). The optic disc of one eye from each individual was analyzed using a confocal scanning laser ophthalmoscope (Heidelberg Retina Tomograph software version 1.11, Heidelberg Engineering, Heidelberg, Germany). Thirteen topographical, volumetric, and shape parameters were compared between the three diagnostic groups. In addition, the individuals were divided into subgroups on the basis of disc size to determine any effect of disc size on the differentiating ability of the confocal scanning laser ophthalmoscope. Differences between the groups were evaluated using an analysis of variance. RESULTS: Glaucomatous optic discs were found to differ from both healthy and OH discs, although no differences in disc area between the groups were identified. On the basis of disc size, differentiating the glaucomatous discs was best for midsized discs of 2 mm2 to 3 mm2. However, no difference was found between healthy and OH discs, even when allowing for disc size. CONCLUSIONS: Ocular hypertensive optic discs (with a clinically normal appearance) could not be distinguished from healthy discs using a confocal scanning laser ophthalmoscopic technique. Glaucomatous optic discs were found to differ from both healthy and OH discs, with a limited effect of disc size.

Analysis of Variance↗
PubMed1997

Sector-based analysis of optic nerve head shape parameters and visual field indices in healthy and glaucomatous eyes.

PURPOSE: To evaluate the correlations between the sector optic nerve head parameters measured by Heidelberg Retina Tomograph (HRT, Heidelberg Engineering, Heidelberg, Germany), version 1.11S, and the visual field. METHODS: One eye was randomly chosen from 55 individuals with glaucoma and 50 healthy individuals. Each participant had at last one Humphrey visual field, program 30-2 (Humphrey Instruments, San Leandro, CA, U.S.A.), and three 10 degrees HRT pictures. From the mean of the three HRT pictures, global measurements, superior (45 degrees-135 degrees), nasal (135 degrees-225 degrees), inferior (225 degrees-315 degrees), and temporal (315 degrees-45 degrees) sector measurements were calculated for the following parameters: disc area, effective area, area below reference, mean height of contour, volume below surface, volume above surface, volume below reference, volume above reference, and third moment. From the visual field results, mean deviation (MD), superior MD, and inferior MD were calculated. For each HRT parameter we calculated the "r" Pearson correlation with the corresponding visual field measures. RESULTS: Within the combined healthy and glaucomatous groups we found highly significant (p < 0.001) correlations between the following HRT parameters and the visual field MD: inferior and mean high of contour (r = -0.53), inferior and third moment (r = -0.52), global and third moment (r = -0.49), inferior and volume above reference (r = 0.47), superior and third moment (r = -0.46), and superior and area below reference (r = -0.44). Correlations between global mean deviation and nasal or temporal sector parameters were generally smaller and less significant. CONCLUSIONS: Inferior and superior HRT sector parameters were correlated with the respective visual field indices. In many cases these correlations were as strong or stronger than with the global equivalent shape measures.

Diagnostic Techniques, Ophthalmological↗
PubMed1996

Pre-injection fluorescence in indocyanine green angiography.

PURPOSE: To verify whether infrared pre-injection fluorescence can be observed in patients undergoing indocyanine green (ICG) angiography. METHODS: Infrared fundus photographs were taken before dye injection for 450 consecutive patients undergoing ICG angiography for different chorioretinal disorders. The authors used a high-resolution videoangiography system with the standard ICG filters inserted (overlap, < 0.5%) and the highest flash intensity. RESULTS: Pre-injection fluorescence was detected in 184 patients (40.8%). It was a strong fluorescence in 75 patients (40.7%) and a faint fluorescence in 109 (59.2%). When fluorescence was strong, it simulated vascular filling on the ICG angiogram. Pre-injection fluorescence resulted from the following lesions: (1) old grayish subretinal hemorrhages (35 patients); (2) lipofuscin-like deposits (65 patients); (3) pigmented choroidal neovascular membranes (72 patients); and (4) serous retinal detachments lasting from several months or years (12 patients). Highly reflecting white lesions were not fluorescent. CONCLUSION: Pre-injection fluorescence of chorioretinal lesions is frequently detectable in patients with diseases requiring ICG examination. A pre-injection photograph may help to avoid misinterpretation of the angiograms. The authors' findings may be interpreted as pseudofluorescence or autofluorescence. Pigments contained in pathologic structures of the ocular fundus may be the source of autofluorescence emissions in the near-infrared range.

Adult↗
PubMed1995

Study of the correlation between average values of optic disc parameters and their measurement variability using stereovideographic digital analysis.

Purpose of our study was to find whether there is a correlation between average values of optic nerve head parameters and their coefficient of variation for repeated measurements. Disc stereo video images were taken with Topcon Imagenet (IS100) and analyzed with the Optic Disc Analysis program. Eleven normal and 9 glaucomatous eyes were selected. A significant correlation was found for horizontal cup/disc ratio (r = -0.037, p = 0.037) and disc area (r = 0.776, p = 0.027) in intra-observer intra-image repeated measurements. Vertical, horizontal and average cup/disc ratios (r = -0.81, r = -0.74, r = -0.78 p < 0.05) showed a significant correlation for intra-observer inter-image repeated measurements. For inter-observer intra-image measurements, a significant correlation was present for average cup/disc ratio (r = -0.64, p = 0.043). Our data show that bidimensional semiquantitative parameters in use for optic nerve head assessment, analyzed by computerized stereovideography, have an intrinsic measurement variability. The variability is significantly related to the value of the measured parameter only when their reference points are determined manually by the operator.

Adult↗
PubMed1995

Synthesis and photobiological properties of 3-acylangelicins, 3-alkoxycarbonylangelicins and related derivatives.

Convenient synthesis of 3-acyl-2H-furo[2,3-h]-1-benzopyran-2-ones, esters of 2-oxo-2H-furo[2,3-h]-1-benzopyran-3-carboxylic acid and 2H-furo[2,3-h]-1-benzopyran-3-carboxamides was accomplished via aromatization of the adducts obtained by a reaction between (E)-5-dimethyl-aminomethylene-6,7-dihydrobenzofuran-4(5H)-one and the appropriate acylacetate or dialkyl malonate. These compounds are angelicin derivatives which were prepared with the aim of obtaining intrinsically monofunctional drugs for photochemotherapy, with only one photoreactive site in their molecule. The new angelicins appear to be free of the known phototoxicity of furocoumarins on the skin and at a genetic level. The 3-carboxylic esters showed significant antiproliferative activity in Ehrlich ascites cells and T2 bacteriophage; the other derivatives were only slightly effective. The features of these compounds are such that they represent a new model for non-toxic agents for photochemotherapy.

Animals↗
PubMed1994

Measurement variability in digital analysis of optic discs.

The optic disc of nine patients with typical glaucomatous disc damage and ten normal controls has been studied by means of the Optic Disc Analysis program of the Topcon Image-net System. Vertical, horizontal and average cup/disc ratio (VC/D, HC/D, AC/D), disc, cup, rim area (DA, CA, RA), cup volume (CV) have been evaluated and the coefficient of variation (COV) of multiple measurements was calculated. For intra-observer intra-image variability assessment, sterovideographs of each disc were taken once and analyzed 10 times (COV range: 1.39-12.08%). Intra-observer interimage variability was evaluated on eight stereovideographs of each disc taken at one minute intervals (COV range: 1.63-96%). Inter-observer intra-image measurements were taken on each disc by 5 different observer (COV range: 1.28-27.08%).

Adult↗
PubMed1991

Functional enuresis: pharmacological versus behavioral treatment.

Treatment of childhood enuresis requires a careful anamnesis, physical examination, urinalysis, and urine culture to determine if a subject is affected with functional or organic enuresis. Functional enuresis (FE) was present in the majority of our patients (168/204). These 168 subjects, aged from 6 to 11 years, were randomly divided into three therapy groups (pharmacological therapy, behavioral therapy, and behavioral therapy with the aid of a personal computer). Our study shows that behavioral therapy gave better results in FE than did pharmacological therapy. We point out the usefulness of combining bladder retention training and behavioral therapy to improve the general maturity and autonomous behavior of the child, and the resultant positive effects on his personality.

Behavior Therapy↗
PubMedDate not supplied

Morphometric analysis of the optic disc surface. The level of smoothness as a diagnostic parameter for glaucoma.

PURPOSE: Since the glaucomatous loss of nerve fibers changes the appearance of the optic disc, we evaluated the morphology of the surface of the optic disc in normal and glaucomatous eyes by using a computerized system to provide the reciprocal position of a large number of points placed on its surface in order to study the clinical significance of differences in the 'smoothness' of optic disc surface. METHODS: The morphology of the optic disc surface was evaluated by means of simultaneous stereoscopic videographic pictures (IMAGEnet X Rev-3.51b-Topcon Europe, The Netherlands): the reciprocal distribution of a large number of points located on the surface of one eye of 100 subjects randomly chosen (45 normal and 55 glaucoma patients) was studied. In order to define the level of 'smoothness' of the optic disc surface, the differences of the relative position of each surface point were studied by measuring the standard deviation (SD) from the average heights of the points (n. ranging from 623 to 1916 depending on the size of the disc area) that identify the optic disc surface. RESULTS: The coefficient of variation of the reciprocal location of the points, placed on the optic disc surface at the different measurements performed by a single operator was 10.4%. The differences in Optic Disc Surface Smoothness (ODSS) between glaucoma and normal group were statistically significant (p < 0.0001 using Mann-Whitney U test). No correlation was detectable between age and standard deviation. The best threshold value, calculated using ROC methodology, able to separate the two groups was: normal group: SD < or = 17.79 (-1 x 10(-2) mm); glaucoma group: SD > -17.79 (-1 x 10(-2) mm). Such threshold value had a sensitivity of 82.1%, a specificity of 92.2% and a diagnostic precision (DP) of 86.5% in dividing the glaucoma group from the normal group. CONCLUSION: ODSS is a global index of optic disc conditions based on quantitative measurements of the morphology of the optic disc surface. As such it does not provide information about the location and the characteristics of optic disc damage. Nevertheless, ODSS measurement is able to separate normal from glaucomatous optic disc with a rather interesting sensitivity, specificity and diagnostic precision (DP). As such it could be useful both for research and clinical applications.

Female↗
PubMedDate not supplied

Retinal nerve fiber layer measured by Heidelberg retina tomograph and nerve fiber analyzer.

PURPOSE: To compare retinal nerve fiber layer (RNFL) thickness measured by Heidelberg retina tomograph (HRT) and nerve fiber analyzer (GDx). METHODS: Twenty eyes of 20 consecutive healthy subjects were recruited for this study. Each subject had a normal visual field and a normal optic nerve head, which was assessed by slit-lamp biomicroscopy using a 90 degrees lens. Using the HRT and GDx, RNFL measurement was calculated as for software vs 2.01 and vs 1.0.14, respectively. Retinal nerve fiber layer thickness was evaluated for the entire annulus surface every 5 degrees degrees. RNFL was assessed by HRT and GDx. HRT RNFL measurement was calculated at 0 microm from the edge, while GDx RNFL measurement at 1.75 disc diameter as for software. The difference between the highest points and the deepest points was calculated and compared. Furthermore, because of the possibility of different scales in the two systems, the following ratio was calculated: superior/inferior, superior/temporal, superior/nasal, inferior/temporal, and inferior/nasal. RESULTS: When the entire RNFL thickness was considered, a significant (p<0.001) difference was found between the HRT and GDx measurements. A difference of 200 microm was found between the highest and the deepest HRT points while a difference of 40 microm was found between the highest and the deepest GDx points. CONCLUSIONS: HRT and GDx RNFL measurements were statistically different in each sector. However, ratio parameters showed no difference between the obtained values except for superior/temporal ratio and inferior/temporal ratio.

Aged↗