Biomedical subjects

O Vattovani

Publications and source records attributed to O Vattovani.

4 recordsLinked to original sources

PubMed2005

Observer interpretation variability of peripapillary flow using the Heidelberg Retina Flowmeter.

PURPOSE: To evaluate the intraobserver and interobserver reproducibility of the automatic full field perfusion image analysis (AFFPIA) program on Heidelberg Retina Flowmeter (HRF) derived perfusion images in a multicentre study group. METHODS: A total of 10 subjects were consecutively recruited in the study. One eye was randomly selected for each patient. Blood flow was assessed by HRF and flow measurements were analyzed by using the AFFPIA program. AFFPIA calculates the Doppler frequency shift and the haemodynamic variables: flow for each pixel. Intraobserver and interobserver reproducibility was calculated for AFFPIA program. The retinal blood flow was calculated in the superior and inferior section, furthermore, each section was divided into three parts: the temporal area, the nasal, and the rim area, as for software, but only the temporal and nasal areas were considered in this study. The blood flow and the area considered were evaluated for each part. RESULTS: When the intraobserver and intraimage reproducibility was studied, the coefficient of variation ranged from 0.4 to 1.9%. When the interobserver and intraimage reproducibility was studied, the retinal blood flow coefficient of variation ranged from 0.52 to 3.30% for the supero-temporal area, from 0.13 to 2.67% for the inferotemporal area, from 0.15 to 2.75% for the supero-nasal area, and from 0.04 to 5.65% for the infero-nasal area. CONCLUSION: Our results with AFFPIA showed an interobserver coefficient of variation of retinal blood flow measurements always less than 6% in both temporal and nasal areas. No significant difference was found among the four observers for the flow measurements.

Adult↗

PubMed2005

Atypical pattern of retardation on GDx-VCC and its effect on retinal nerve fibre layer evaluation in glaucomatous eyes.

PURPOSE: To assess the effect of atypical pattern of retardation (APR) on retinal nerve fibre layer (RNFL) measurements made by scanning laser polarimetry (SLP) with variable corneal compensation (GDx-VCC) in glaucomatous eyes. METHODS: One eye each of 30 glaucomatous patients (average mean deviation (MD): -6.4+/-4.8) with APR on GDx-VCC retardation map were selected. In total, 34 glaucomatous, age- and severity-matched eyes (average MD: -7.0+/-5.3) and 36 age-matched healthy subjects, both with a normal pattern of retardation (NPR) represented control groups. APR on retardation maps was characterized by alternating peripapillary circumferential bands of low and high retardation, or high retardation areas arranged in a spokelike pattern, or high retardation nasal and temporal splotchy areas. Typical scan score (TSS) was extracted for each included eye. GDx-VCC parameters (mean+/-SD) in the two groups of glaucomatous eyes were compared with healthy eyes' corresponding values (Mann-Whitney U-test). Areas under receiver operating characteristic (AUROC) curves were generated to assess the APR effect on the parameters' diagnostic ability. RESULTS: All parameters discriminated adequately between healthy and glaucomatous eyes with NPR (AUROCs > or =0.9 for nine parameters). On the contrary, considering healthy and glaucomatous eyes with APR, four thickness parameters could not separate the two groups and AUROCs > or =0.85 appeared only for Inferior and Superior Ratio, NFI, Max Modulation. CONCLUSION: APR may void the effect of custom compensation and provide spurious RNFL thickness measurements. When a printout of glaucomatous eyes with APR is evaluated, it is proper to rely on ratios, modulation parameters, and NFI, since the diagnostic ability of thickness parameters is significantly reduced.

Aged↗

PubMed1994

Corneal endothelial function in diabetes: a fluorophotometric study.

The corneal endothelium in diabetics is particularly susceptible to surgical trauma. This is related to the presence of morphological alterations of endothelial cells and to a supposedly concomitant functional failure of the endothelium in these patients. The aim of our study was to evaluate the corneal endothelial function in diabetics. A fluorophotometric study was performed on 3 groups of diabetic subjects without retinopathy, with nonproliferative retinopathy and with proliferative retinopathy compared with an age-matched control group. We evidenced a significant increase in corneal thickness and in passive corneal permeability in diabetics with severe retinal involvement. These findings are not related with a proportional significant increase in endothelial pump function. We suggest an altered regulation in corneal hydration in diabetic patients depending on the functional failure of endothelial cells that is likely to be connected with corneal biochemical modifications caused by an altered glucidic metabolism.

Aged↗

PubMedDate not supplied

Comparing measurements of retinal nerve fiber layer thickness obtained on scanning laser polarimetry with fixed and variable corneal compensator.

PURPOSE: To compare retinal nerve fiber layer (RNFL) thickness measurements obtained on scanning laser polarimetry (SLP) with commercially available instruments coupled with fixed (FCC) and variable corneal compensator (VCC). METHODS: Forty-two eyes of 42 patients underwent a complete ophthalmologic evaluation and achromatic automated perimetry (24-2 program, SITA standard strategy). Nineteen eyes were healthy (average mean deviation: -0.12 dB +/- 2.26) and 23 glaucomatous (average mean deviation: -4.92 dB +/- 6.49). All patients underwent SLP with both FCC and VCC. Adequate compensation of corneal birefringence on FCC-SLP was checked acquiring macular retardation map (MRM). RNFL thickness was evaluated considering superior and inferior maximum (SM, IM), average thickness and ellipse average (AT, EA), and superior and inferior average (SA, IA). Mean values (+/-SD) for each parameter measured by the two polarimeters were compared and linear regression calculated. The ability of each parameter to discriminate between normal and glaucomatous eyes was evaluated on both polarimeters calculating area under ROC curve. RESULTS: A significant linear correlation for all parameters was noted (r range: 0.65-0.78). VCC produced slightly higher thickness values than FCC, both in normal and glaucomatous eyes. On both polarimeters, area under ROC curve for all parameters discriminated adequately healthy from glaucomatous eyes (range: 0.68-0.81). CONCLUSIONS: In a highly comparable and selected group of normal and glaucomatous eyes, FCC-SLP and VCC-SLP showed considerable concordance in measuring peripapillary RNFL thickness, both for sectorial and global parameters. Proper corneal birefringence compensation provided separation of normal from glaucomatous eyes on both polarimeters.

Adult↗