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Purpose: To determine the influence of the contour line position on the Heidelberg Retina Tomograph (HRT) parameters and on the diagnostic capacity of the system., Methods: Thirty subjects with clinical diagnosis of primary open angle glaucoma and 30 healthy subjects were recruited. For each patient only one eye was randomly chosen. All optic nerve heads (ONH) were analysed with HRT. An operator drew the right contour line in all the considered images, while a second user increased and decreased radius size of 0.05 and 0.1 mm, recalculating each time all the HRT parameters. Five different disc area subgroups were obtained and for each subgroup discriminant formulas were applied. Sensitivity, specificity, and diagnostic precision were considered for each subgroup., Results: Among the HRT parameters, rim area was the most sensitive to the contour line position changes when the radius variation was greater than +/-0.1 mm. For most of the HRT parameters, the differences between subjects with glaucoma and control group did not significantly change when the disc area increased or decreased. Highest diagnostic capacity was observed for Mikelberg and Mardin formulas when the contour line was narrowed, while the cup shape measure value had the best diagnostic capacity when the contour line was larger., Conclusions: When the disc area was modified, the sensitivity, specificity, and diagnostic capacity of discriminant formulas changed according to the ONH size; however, in the glaucoma clinic, small errors (within +/-0.05 mm) in contour line position did not significantly influence the final HRT diagnostic capacity.

Purpose: To verify whether scanning laser polarimeter with the new variable corneal compensation algorithm (GDx VCC) and scanning laser ophthalmoscopy (Heidelberg Retina Tomograph (HRT)) allow measuring retinal ganglion cell loss in patients with multiple sclerosis (MS)., Patients and Methods: We enrolled 23 MS patients with a history of previous demyelinating monocular optic neuritis. Examination included visual evoked potentials (VEPs), scanning laser ophthalmoscopy, and scanning laser polarimeter. HRT was performed to assess optic nerve head (ONH) shape, while GDx VCC was used to evaluate the retinal nerve fibre layer thickness (RNFLt) around the ONH. Statistical analysis was performed comparing results obtained for each eye with the available normative database and with the unaffected fellow eye., Results: When the affected eye group was compared to the fellow-eye group, a significant (P<0.05) difference was found for few GDx VCC parameters. In contrast, no significant correlation was observed between clinical assessment and imaging techniques when the normal database of HRT and GDx VCC was used. A significant association was observed between VEP latency and some GDx VCC parameters., Conclusions: Our results suggested that scanning laser polarimetry could detect loss of ganglion cells following demyelinating optic neuritis, but further studies are needed.

Purpose: The aim of this study was to evaluate and compare 4 different discriminant analysis formulas and the new Glaucoma Probability Score (GPS) for the detection of morphometric optic nerve head changes in chronic open-angle glaucoma., Methods: This is a prospectively planned cross-sectional study. Two hundred and fourteen consecutive eyes were recruited into this study. For each patient, the eyes were evaluated by a slit lamp examination, and the visual fields were assessed by a Humphrey Field Analyzer 750 (HFA, Humphrey Inc, San Leandro, CA), using the standard full threshold 24-2 (Swedish Interactive Threshold Algorithm) program. The optic nerve heads were morphometrically evaluated using the Heidelberg Retina Tomograph 3 (HRT 3, Heidelberg Engineering, Heidelberg, Germany; software version 3.0). From the HRT data, 4 discriminant analysis formulas and the GPS were considered. All data were analyzed by Student t test and Pearson r coefficient. A linear regression model was also used to determine the independent contribution of variables included in the model. Sensitivity, specificity, diagnostic precision, and receiver operating characteristic curve areas were calculated for all the 5 methods examined. kappa statistic was used to study the agreement among, and between, the 5 different methods., Results: One hundred and nineteen normal eyes and 95 eyes with primary open-angle glaucoma were included in the study. No significant difference was found between the 2 study subgroups in both age and refractive error. Significant (P<0.001) correlations were found between visual field indices and the HRT parameters. Sensitivity, specificity, and diagnostic precision of the 4 formulas ranged between 50% and 99.16%. Bathija et al's formula had the highest diagnostic precision, followed by Mikelberg's formula. Using kappa statistics, kappa ranged from 0.177 to 0.528 when comparing each single discriminant formula with the GPS., Conclusions: The GPS showed similar sensitivity and specificity to the Mikelberg and Bathija formulas; this method is a promising one for differentiating between healthy and glaucomatous eyes, requiring no subjective user input.

Purpose: To evaluate the capacity of a new topographic map analysis to detect abnormal optic discs from healthy ones in a new cohort of subjects., Patients and Methods: Only one eye was chosen randomly from each subject included in the study. In total, 20 normal eyes with a normal visual field, an IOP of <22 mmHg and no history of glaucoma in their family, and 20 glaucomatous eyes with an abnormal visual field and an open angle were selected. All the subjects were examined with the Heidelberg Retina Tomograph (HRT, Heidelberg Engineering GMBH, Heidelberg, Germany) and Humphrey Perimeter, program 30-2 (Humphrey Instrument, Inc., San Leandro, CA, USA). Topographic maps analysis was performed to each HRT optic nerve head image. Sensitivity, specificity, and diagnostic precision were calculated., Results: When the topographic map analysis was applied to the group, a sensitivity of 80%, a specificity of 75%, and a diagnostic precision of 77.5% were obtained., Conclusion: Using the topographic map analysis, the HRT capacity to differentiate normal optic discs from those with glaucoma was similar to those already published in the literature, but using this technique there is no input from the observer to draw the contourline and reference plane is not necessary.

Purpose: To evaluate which Heidelberg Retina Tomograph (HRT) parameter is the best predictor of frequency doubling technology (FDT) sensitivity by using a sector based analysis between FDT and optic nerve head shape parameters such as cup shape measure (CSM) and rim area (RA), which have been shown to have the best correlation with FDT indices among all the HRT parameters., Methods: One eye was randomly chosen from 100 patients with primary open angle glaucoma (abnormal visual field and/or abnormal optic nerve and untreated intraocular pressure above 21 mm Hg). All the patients were examined with Humphrey field analyzer (HFA), program 24-2, SITA standard, FDT program C 20, and HRT. RA and CSM for the HRT analysis and mean deviation, pattern standard deviation, and the sensitivity of each tested point for the FDT test were considered in this study. All the parameters were calculated as both global and sector measurements. Findings were analyzed using Pearson's correlation coefficient and linear regression model., Results: Significant (p<0.001) correlation was found between FDT indices and HRT RA and CSM. Significant (p<0.001) sector correlation was found between FDT sensitivity and RA and CSM, but when a linear regression model was applied, RA was the most predictive parameter of FDT. Temporal CSM was more strongly correlated to FDT fovea sensitivity than temporal RA. Furthermore, sector HRT parameters were better correlated to HFA than to FDT., Conclusions: In this glaucomatous group, cup shape measure and RA were significantly correlated to FDT indices. RA was more predictive of FDT abnormality than CSM in all the considered sectors except in the temporal one. However, HFA was a stronger predictor of HRT parameters than FDT.

Purpose: To evaluate the association between Heidelberg Retina Tomograph (HRT) parameters and the Frequency Doubling Technology (FDT) indices in ocular hypertension or primary open angle glaucoma patients., Methods: One eye was randomly chosen from 85 patients with primary open angle glaucoma (abnormal visual field and/or abnormal optic nerve and untreated IOP > 21 mm Hg) and ocular hypertension (normal visual field and normal optic nerve and untreated IOP > 21 mm Hg). All the patients were examined with Humphrey Perimeter program 30-2 full threshold, FDT program C 20-5, and HRT. Findings were analyzed using Pearson's correlation coefficient and linear regression., Results: Within the entire sample of studied subjects we found a statistically significant correlation (Pearson's r) (P < 0.05) between FDT mean deviation and RA, CA, RV, CSM, RNFLt, and RNFLc of HRT, and between FDT pattern standard deviation and RA, CA, VOLC, CV, RV, CSM, RNFLt, and RNFLc of HRT. Linear regression analysis showed that cup shape measure was the most predictive parameter for FDT MD. No correlation was found between HRT parameters and FDT PSD indices in the glaucoma subgroup; in the ocular hypertensive subgroup some correlation was found between FDT PSD and some of the HRT parameters., Conclusion: In the entire group, cup shape measure showed to be the most significant factor correlating functional and morphologic changes. The presence of significant correlations between some HRT parameters and visual field indices in the ocular hypertensive and glaucoma subgroup suggested that HRT parameters and FDT indices could detect glaucoma damage differently.

Purpose: To evaluate the intraobserver reproducibility of a software designed to assess retinal blood flow with the Heidelberg Retina Flowmeter (HRF)., Methods: Ten subjects were consecutively recruited, and one eye of each patient was randomly selected for study. Blood flow measurements were analyzed by using an automatic full field perfusion image analysis (AFFPIA) program, which calculates the Doppler frequency shift and hemodynamic variables (flow, volume, and velocity) for each pixel. The resulting perfusion image is processed with respect to underexposed and overexposed pixels, saccades, and retinal vessel tree. Intraobserver reproducibility was calculated for the AFFPIA program. All the optic nerve heads were horizontally divided into three sections (superior, central, and inferior). The retinal blood flow was calculated in the superior and inferior section, and each section was further divided into three areas (temporal, nasal, and rim). The blood flow was evaluated for each area., Results: When the same observer analyzed the same image five times (intraobserver intraimage reproducibility), the AFFPIA coefficient of variation ranged from 0.5% to 5% in the temporal area, from 0.1% to 5.3% in the nasal area, and from 0.5 to 28% in the rim area. When the same observer analyzed three different images of the same section once (intraobserver interimage reproducibility), the AFFPIA coefficient of variation of flow measurements ranged from 1% to 7.3% in the temporal area, from 1.5% to 10% in the nasal area, and from 2 to 30% in the rim area., Conclusion: Retinal blood flow measured by HRF and analyzed by AFFPIA had good intraobserver reproducibility. The reproducibility was significantly better in the temporal and nasal areas than in the rim area.

Aim: To evaluate the validity of cumulative rim/disc area (RA/DA) curve analysis as a clinical tool for the identification of glaucoma induced optic disc pathology., Methods: 71 normal and 83 glaucomatous eyes were evaluated from a series of 154 subjects recruited for this study. For each eye, the cumulative distribution of RA/DA was calculated from 36 equally spaced rim sectors of each optic disc obtained by the automatic evaluation of simultaneous videographics (Image-net X Rev.3/51b). To increase the sensitivity of this analysis in early glaucoma and in normal eyes, these cumulative curves were subsequently divided into two equal segments and the slopes of their respective regression lines compared., Results: The median RA/DA value obtained from the 36 sectors was significantly different in glaucomatous eyes compared with normals (p < 0.001). Nevertheless, the curves (5th-95th percentile of the cumulative curves distribution) of early glaucomatous eyes fell within the normal range. When the cumulative curve of these marginal cases was then divided into two equal segments, the comparison of the slopes of the regression lines showed a significant difference (p < 0.05) in 100% of early glaucomatous eyes. Furthermore, normal eyes were shown to be true negatives in 93% of the cases in which no significant difference between the two slopes was observed., Conclusion: Analysis of the RA/DA cumulative curve from 36 sectors of the optic disc was a valid method for the identification of glaucomatous disc pathology; however, a further calculation of the slopes of the two RA/DA regression lines was needed to identify early glaucomatous damage.

Purpose: To evaluate the correlation between computerised visual field testing and optic disc morphometric parameters (rim area, rim/disc area ratio, cup/disc area ratio and optic disc surface smoothness (ODSS)) in the follow-up of a group of patients affected by primary open angle glaucoma (POAG)., Methods: Reliable automated perimetry (Humphrey 640 VFA, central 30-2 threshold program) was performed at T0 (the enrollment time), T1 (after 6 +/- 1 months; range 5-7 months), T2 (12 +/- 1 months), T3 (18 +/- 1 months), and T4 (the end of the follow-up period: 24 +/- 2 months) in one eye randomly chosen from each of 30 POAG patients. Computerised optic disc analysis (IMAGEnet X Rev-3-51b, Topcon Europe, The Netherlands) was performed at T0 and T4. To evaluate the correlation between morphometric parameters and computerised visual field testing, the stability or worsening of visual field test was evaluated by means of 'Mean Deviation linear regression analysis' (STATPAC 2 software); that of morphometric parameters was studied using their coefficients of variation. A rank of '0' was assigned to stability and a rank of '1' to worsening. The Spearman rank correlation coefficient was used to evaluate statistically the correlations between visual field analysis and morphometric parameters. Furthermore kappa statistic was used to evaluate the agreement of morphometric parameter changes with visual field progression analysis., Results: According to the MD slope regression analysis, in 18 patients the visual fields were stable while in 12 they were worsening during the follow-up period. In 86.65% of patients (n = 26) the morphometric parameter ODSS and visual field analysis were concordant (p < 0.0001). In 80% of patients (n = 24) the cup/disc area ratio and visual field analysis were concordant (p < 0.001). The other morphometric parameters (rim area, rim/dics area ratio) were less correlated with visual field analysis than ODSS (p < 0.05). The agreement of visual field analysis with all the morphometric parameters was good (kappa = 0.690, 95% confidence interval (CI) of kappa = 0.589-0.790). The agreement of visual field analysis with ODSS and cup/disc area (kappa = 0.688; 95% CI = 0.511-0.864) was better than the agreement of visual field analysis with rim area and rim/disc area ratio (kappa = 0.438; 95% CI = 0.260-0.655)., Conclusion: Analysis of the progression of visual field damage and optic nerve head morphometric parameters should both be taken into account in glaucoma follow-up. Among the morphometric parameters evaluated by means of Topcon IMAGEnet, ODSS and (to a lesser extent) the cup/disc ratio should have the greatest weight.

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.

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%).