Biomedical subjects

Christian Y Mardin

Publications and source records attributed to Christian Y Mardin.

16 recordsLinked to original sources

PubMed2006

Measurement of autofluorescence in the parapapillary atrophic zone in patients with ocular hypertension.

PURPOSE: The purpose of the study was to investigate area and intensity of parapapillary autofluorescence in patients with ocular hypertension and controls. PATIENTS AND METHODS: Forty-two consecutive patients with ocular hypertension and 25 controls were investigated in a controlled prospective cross-sectional trial. All patients and controls were members of the Erlangen Glaucoma registry and received complete ophthalmologic examination and detailed standardized glaucoma examination, including 24-h IOP measurement, perimetrie (G1, three phases) and 15 degrees stereographic slides of the optic disc. Additionally, patients and controls were investigated with VEP with blue on yellow pattern stimulation and confocal scanning laser ophthalmoscope (HRA II, Heidelberg Engineering, Dossenheim, Germany) to detect lipofuscin in the parapapillary atrophic zone. Eyes with retinal diseases or pathologic changes of retinal pigmentepithelium were excluded. Extension of parapapillary area with increased autofluorescence compared (qualitatively) to background autofluorescence around the optic disc and the level of autofluorescence (quantitatively) in the area of qualitatively increased autofluorescence was measured. Patients and controls did not differ significantly concerning age. RESULTS: The area of parapapillary autofluorescence was significant larger in patients with ocular hypertension than in the control group (0.21+/-0.17 mm(2) versus 0.07+/-0.06 mm(2); P<0.001, Mann-Whitney U-test). An increased latency of blue-on-yellow pattern VEP was seen in patients with OHT with increasing parapapillary autofluorescence area (r=0.496; P<0.001, Spearman-Rho test). CONCLUSION: Parapapillary autofluorescence is increased in patients with ocular hypertension. Patients with large area of parapapillary autofluorescence had also an increased latency in blue on yellow pattern VEP.

Cross-Sectional Studies↗

PubMed2006

Visual evoked potentials of the blue-sensitive pathway under cold provocation in normals and glaucomas.

BACKGROUND: Vascular dysregulation in open-angle glaucomas can be identified by measuring the blood circulation during exposure to cold water. Aim of this study was to find out whether the same cold stimulus would lead to functional changes in the visual evoked potentials (VEP) of the short-sensitive pathway in normals and glaucoma patients. PATIENTS AND METHODS: Blue-on-yellow pattern-visual evoked potentials were studied in 22 healthy control persons and 47 patients with primary open-angle glaucoma (25 high-pressure glaucomas, 22 normal pressure glaucomas with clinical signs of vasospastic hyperreactivity). A blue stripe pattern, presented in onset-offset mode on a yellow adaptation light served as the stimulus. Cold provocation was initiated by dipping one hand of the patient into cold water of 3 degrees C to 5 degrees C. The onset amplitudes and peak times were measured without cold exposition as well as two and four minutes after the cold exposition began. RESULTS: In the group of vasospastic glaucoma patients a significant reduction of visual evoked potential-amplitudes was observed during cold provocation (amplitude before ice exposition: 4.17 microV, amplitude following two minutes of ice exposition: 3.52 microV; paired test: P < 0.01). Other subject groups showed no significant amplitude reductions after cold provocation. Peak times of both open-angle glaucoma groups (132.3 +/- 18.7 milliseconds in high pressure, 132.7 +/- 14.5 milliseconds in normal pressure) were significantly increased in comparison to normals (117.4 +/- 8.0 milliseconds). However, no significant influence of the cold provocation on peak times could be found in all groups. CONCLUSION: Peak times of the blue-on-yellow visual evoked potentials are significantly prolonged in patients with primary open-angle glaucomas. Cold provocation causes a significant amplitude reduction of the blue-on-yellow visual evoked potential in the present normal-pressure glaucoma patients and reflects vascular dysregulation in patients with vasospastic hyperreactivity.

Blood Pressure↗

PubMed2006

Improving glaucoma diagnosis by the combination of perimetry and HRT measurements.

PURPOSE: The aim of this study was to determine, whether the combination of morphologic data of the optic nerve head and visual field (VF) data would improve diagnosis of glaucoma, on the basis of the measurements alone. PATIENTS AND METHODS: Eighty-eight perimetric glaucomatous and 88 normal optic discs from the Erlangen Glaucoma Registry were matched for age. All normals and patients were examined in a standardized manner (Slitlamp biomicroscopy, gonioscopy, 24 h-applanation tonometry, automated VF testing, 15-degree optic disc stereographs, and Heidelberg Retina Tomograph (HRT)-scanning of the optic disc). The HRT variables were calculated in 4 optic disc sectors. All variables were calculated with the software's standard reference plane. To gain the same allocation of sectors as provided by the HRT software, the VF responses were averaged within 4 sectors. Classification results of these VF responses were compared with the summarized results within 4 sectors. Six different combinations of morphologic and VF data were used to assess their suitability to diagnose the disease. HRT measurements, and the standard output of the Octopus (HRT/PERI1), HRT measurements and the summarized sectors and their standard deviations (HRT/PERI2), HRT measurements, standard output of the octopus and the summarized sectors and their standard deviations (HRT/PERI1/PERI2), standard output of the Octopus (PERI1), summarized sectors of the Octopus and their standard deviations (PERI2) and HRT measurements. To assess the diagnostic value of the different data sets machine learning classifiers, stabilized linear discriminant analysis, classification trees, bagging, and double-bagging were applied. RESULTS: Combination of morphologic and VF data improved the automated classification rules. The accuracy to diagnose glaucoma just by VF and HRT indices was maximized for double-bagging using both diagnostic tools. An estimated misclassification probability of less than 0.07 could be achieved for the primary open angle glaucoma patients combining HRT and VF sectors by double bagging. So highest sensitivity was 95% and specificity 91%, achieved by double-bagging and combination of HRT, PERI1, and PERI2. CONCLUSIONS: The combination of optic disc measurements and VF data could not only improve glaucoma diagnosis in future, but could also help to find an objective way to diagnose glaucomatous optic atrophy. The limitation of the topographic relationship between structure and function is the individual variability of the optic disc morphology and the subjective variability of VF testing.

Female↗

PubMed2005

Influence of optic disc size on parameters of retinal nerve fiber analysis with laser scanning polarimetry.

PURPOSE: The aim of the study was to evaluate the influence of optic disc size on the variables of laser scanning polarimetry (GDx). PATIENTS AND METHODS: One hundred and nineteen healthy controls and 161 patients with ocular hypertension (OHT) received detailed ophthalmologic investigation with respect to glaucoma including retinal nerve fiber analysis with GDx (Version 3.0.05x1; Laser Diagnostic Technologies Europe). Optic disc size was measured with planimetry using 15 degrees optic disc photographs. With respect to frequency of optic disc size in the normal population patients were divided in quartiles of equal sample size. RESULTS: The ratio between retinal nerve fiber layer thickness in the superior and inferior areas in relation to the nasal and temporal regions decreases significantly with increasing optic disc size and the difference between the highest and lowest retinal nerve fiber layer thickness decreases significantly with increasing optic disc size. The results of multivariate neural network analysis increased with larger optic disc size in controls as well as in patients with OHT. Linear regression analysis showed an increase of 9 units (the Number) per 1 mm(2) of optic disc size. A Number above 30, which indicates suspected glaucoma, was detected in more than a third of the normal population investigated if the optic disc area was larger than 3.5 mm(2). Overall, patients with OHT had a higher Number than controls (20.5+/-11.5 vs. 18.1+/-10.4; p>0.05), but the difference between the two groups did not reach a significant level. CONCLUSIONS: Retinal nerve fiber analysis in patients with an optic disc size larger than 3.5 mm(2) should be interpreted carefully; the Number in particular requires corrections for optic disc size.

Adolescent↗

PubMed2005

Predictive factors for progressive optic nerve damage in various types of chronic open-angle glaucoma.

PURPOSE: To evaluate whether various types of chronic open-angle glaucoma differ in predictive factors for progression of glaucomatous optic nerve damage. DESIGN: Observational cohort study. METHODS SETTING: Prospective observational clinical study. PATIENTS: 517 eyes of 300 Caucasian patients with chronic open-angle glaucoma with elevated intraocular pressure (primary open-angle glaucoma, n = 289; secondary open-angle glaucoma, n = 50) and with normal intraocular pressure (n = 178). OBSERVATION PROCEDURE: During follow-up (median: 49 months, 6 months-130 months), all patients underwent repeated evaluation of color stereo optic disk photographs and white-on-white visual field examination. MAIN OUTCOME MEASURES: Progression of glaucoma was defined as neuroretinal rim loss during the study period. RESULTS: For patients with elevated intraocular pressure, significantly predictive factors for eventual progression were older age, advanced perimetric damage, smaller neuroretinal rim, and larger area of beta zone of parapapillary atrophy. In contrast, in the normal intraocular pressure group, a significant predictive factor was presence of disk hemorrhages at baseline. Within the patients with elevated intraocular pressure, the primary open-angle glaucoma group and the secondary open-angle glaucoma group did not differ in predictive factors for progression of glaucoma. CONCLUSIONS: Open-angle glaucoma patients with normal intraocular pressure and open-angle glaucoma patients with elevated intraocular pressure differ in predictive factors for eventual progression of glaucomatous optic nerve damage. It may have clinical importance and may be helpful in the discussion of the pathogenesis of the glaucomas.

Adolescent↗

PubMed2005

Association between localized visual field losses and thickness deviation of the nerve fiber layer in glaucoma.

PURPOSE: To perform a correlation between morphology and function by studying local perimetric field losses and thickness reduction of the nerve layer in corresponding areas. METHOD: Forty-seven patients with "preperimetric" open-angle glaucoma, 95 patients with "perimetric" open-angle glaucoma, and 75 control subjects had perimetric (Octopus) and polarimetric measurements. Criteria for exclusion: optic discs larger than 4 mm, media opacities, polarimetric hourglass pattern in the macular image. Thickness values of the retinal nerve fiber layer were determined in 14 upper and 14 lower sectors (10 degrees each) as well as nasally and temporally (40 degrees each) as provided from the GDx (software version 4000). The healthy control subjects served to determine age-corrected thickness deviation in all sectors. Analyses were calculated in eight nerve fiber bundle related areas. Due to non-linear relationships between perimetric defects and corresponding thickness deviation non-parametric tests were used. RESULTS: Localized visual field defects in the present perimetric patients were highest in upper and lower visual field areas abutting the nasal meridian. Thickness loss of nerve fiber layer however was highest in more circumferential upper and lower nerve fiber bundles. Correlations between local mean defects and deviation of the retinal nerve fiber layer thickness from normals showed a clear association for corresponding areas. The correlation coefficients were significant (P < 0.01) for all arcuate superior and inferior visual field zones except horizontally and not for the area of the lower nasal step. CONCLUSION: The present correspondence map indicates that focal perimetric defects can be identified best polarimetrically if they occur in the arcuate bundles of the visual field. A lack of correspondence was observed in the area of the papillo-macular bundle.

Female↗

PubMed2003

Comparison between central corneal thickness and IOP in patients with macrodiscs with physiologic macrocup and normal-sized vital discs.

BACKGROUND: Macrodiscs with physiologic macrocups and elevated intraocular pressure (IOP) are frequently suspicious for glaucoma. Patients with an elevated c/d ratio and an IOP of more than 21 mmHg are often treated for glaucoma. We investigated a possible relationship between macrodiscs, IOP and central corneal thickness. METHODS: Using the Erlangen glaucoma registry, 341 out of 1,096 consecutive patients with unremarkable and repeated visual field (Octopus 500, G1-3, MD<2.1) were selected. Most of these patients had been sent as glaucoma suspects. The following data were collected: corneal ultrasound pachymetry (Tomey, AL-2000), IOP profile, visual acuity and central corneal power. The morphometric analysis was performed by planimetry using the Littmann formula. Optic nerve heads with a disc area of more than 3.1 mm(2) were defined as macrodiscs. RESULTS: Patients were subdivided into the following groups: group A: healthy macrodiscs, IOP <22 mmHg (87 patients); group B: healthy macrodiscs, IOP >21 mmHg (66 patients); group C: normal-sized healthy discs, IOP <22 mmHg (93 patients); group D: normal-sized healthy discs, IOP >21 mmHg (95 patients). Mean corneal thickness was: group A: 575+/-36 microm, group B: 596+/-37 microm, group C: 557+/-31 microm and group D: 585+/-38 microm ( P=0.003). Mean central corneal power measured: group A: 41.7+/-1.3 D, group B: 42.4+/-1.3 D, group C: 43.0+/-1.2 D and group D: 42.8+/-1.2 D ( P<0.05). The maximum of IOP was: group A: 17.6+/-3.1, group B: 26.2+/-4.1, group C: 17.2+/-3.4 and group D: 29.7+/-5.5 mmHg. Optic disc size measurements were: group A: 3.91+/-0.66, group B: 3.65+/-0.6, group C: 2.56+/-0.30 mm(2) and group D: 2.39+/-0.39 microm, respectively. CONCLUSIONS: Macrodiscs with elevated IOP have a higher corneal curvature (mean: +0.7 D) and a thicker central cornea (mean: +21 microm) compared to macrodiscs without elevated IOP. An exact evaluation of optic disc morphology in combination with pachymetric and keratometric measurements in relation to IOP could avoid an overtreatment in patients with suspect primary open-angle glaucoma.

Case-Control Studies↗

PubMed2003

Combined use of frequency doubling perimetry and polarimetric measurements of retinal nerve fiber layer in glaucoma detection.

PURPOSE: The aim of this study was to evaluate the diagnostic usefulness of the combined use of frequency-doubling technology (FDT) perimetry and polarimetry of the retinal nerve fiber layer. DESIGN: Cross-sectional study. METHODS: Seventy ocular hypertensive patients (normal optic disk and standard perimetry, elevated intraocular pressure [>21 mm Hg]), 59 patients with "preperimetric" open-angle glaucoma (glaucomatous optic disk atrophy, elevated intraocular pressure [>21 mm Hg], no visual field defect in standard perimetry), 105 patients with "perimetric" open-angle glaucoma (glaucomatous optic disk atrophy and clearly marked visual field defect), and 73 control subjects had FDT screening (protocol: C-20-5) and polarimetric measurements (GDx). Criteria for exclusion: optic disks larger than 4 mm(2), media opacities, patients younger than 33 years or older than 66 years. None of the subjects had earlier FDT perimetry. One eye of each patient and control subject entered the statistical evaluation. Database and statistical software were used for case-wise recalculation of all missed localized probability levels to create a FDT screening score. RESULTS: At a predefined specificity of 94.5% in control eyes, discrimination between "perimetric" glaucoma and normal subjects is superior using the FDT perimetry (sensitivity = 84.8%) in comparison to polarimetry (sensitivity = 63.8%), whereas sensitivity is similar with both methods in "preperimetric" patients (GDx, FDT: 25.4%). In several cases, patients classified as glaucomatous by the GDx are not the same patients as identified by the FDT perimetry. Therefore, a two-dimensional discrimination analysis can increase correct positive classification. Using a linear combination of the present FDT screening score and polarimetry ("the number"), 92.4% of "perimetric" glaucoma eyes and 44.1% of "preperimetric" glaucoma eyes have been classified as glaucomatous. CONCLUSION: Joint usage of polarimetry and FDT perimetry indicate that a combination of different techniques which can uncover different glaucoma properties, might be helpful in early glaucoma detection.

Cross-Sectional Studies↗

PubMed2003

[In-vivo measurement of autofluorescence in the parapapillary atrophic zone of optic discs with and without glaucomatous atrophy].

BACKGROUND: To assess the level of autofluorescence (lipofuscin) of atrophic parapapillary zones in different stages of glaucomatous optic disc atrophy. METHODS: Controlled cross-sectional prospective analysis of 79 consecutive eyes (15 normals as controls, 26 with ocular hypertension, 38 with primary open angle glaucoma). Eyes with retinal diseases or retinal pigment epithelial pathologies were excluded. The confocal scanning laser ophthalmoscope (HRA, Heidelberg Retina Angiograph) was used after lipofuscin excitation with argon blue laser (488 nm) to detect parapapillary autofluorescence in a spectrum above 500 nm. Size, extension of the parapapillary autofluorescent area and its mean distance to the optic nerve head were measured using the HRA standard software. Additional optic nerve head photographs taken with the 15 degrees Zeiss telecentric fundus camera (30 degrees camera with 2 x magnifier) were examined by two experienced ophthalmologists to determine the stage of glaucomatous optic disc atrophy (stages 0 to 4). RESULTS: Very small autofluorescent areas were found in vital discs (optic nerve glaucoma stage 0) in the parapapillary atrophic area (0.08 +/- 0.12 mm (2)) in contrast to glaucomatous discs in stage 1 (0.24 +/- 0.26 mm (2)) and stages 2, 3 and 4 (0.59 +/- 1.29 mm (2), logistic regression analysis r = 0.71; P = 0.029). The circular extension of the autofluorescent area correlated borderlined with the stage of the glaucomatous disc atrophy (higher glaucoma stages: r = 0.82; P = 0.09). The autofluorescent area was larger in OHT than in controls (0.11 mm (2) vs. 0.04 mm (2), P < 0.03). The circular extension of the autofluorescent area was longer in OHT than in controls (0.5 mm vs. 1.15 mm, P < 0.04). CONCLUSIONS: As a sign of pronounced lipofuscin accumulation in the parapapillary atrophic zone higher degrees of fundus autofluorescence can be detected in OHT and manifest primary open angle glaucoma in contrast to normals. The lipofuscin accumulation is correlated with the stage of progression of glaucoma and the stage of optic disc atrophy. The detection of active parapapillary autofluorescent areas especially in OHT may offer the ophthalmologist an important tool for early diagnosis.

Adult↗

PubMed2003

Primary congenital glaucoma: a novel single-nucleotide deletion and varying phenotypic expression for the 1,546-1,555dup mutation in the GLC3A (CYP1B1) gene in 2 families of different ethnic origin.

PURPOSE: To present new molecular genetic data on primary congenital glaucoma from 2 families, 1 isolated case and 3 familial cases due to mutations in the cytochrome P-450 1B1 (CYP1B1) gene. METHODS: All diagnoses were made by slit-lamp biomicroscopy, gonioscopy, cornea and optic disk measurements, ultrasound-biometry, and automated static threshold perimetry where possible. Mutation screening was performed by direct sequence analysis of DNA extracted from peripheral blood of the patients and their relatives. RESULTS: For the isolated case, a child of 4 years, a homozygous nucleotide deletion within a tetrad of cytosines (nt622-625, 622delC) was found leading to a predicted nonsense codon 93 truncating the protein by 450 amino acids. For the familial cases, the 3 affected members showed a homozygous mutation 1,546-1,555dupTCATGCCACC for which 9 healthy relatives proved to be heterozygous. The phenotypic expression of these 3 patients varied widely. CONCLUSION: Our results confirm the crucial role of CYP1B1 mutations for congenital glaucoma.

Aryl Hydrocarbon Hydroxylases↗

PubMed2003

Optic disc morphometry correlated with confocal laser scanning Doppler flowmetry measurements in normal-pressure glaucoma.

PURPOSE: To examine the relationship between morphologic optic disc parameters and hemodynamic parameters as measured by confocal laser scanning Doppler flowmetry in patients with normal-pressure glaucoma. METHODS: The study included 91 eyes of 54 patients with normal-pressure glaucoma (mean age: 57.7 +/- 9.8 years), and 136 eyes of 77 age-adjusted normal controls. Color stereo optic disc photographs were morphometrically examined, and confocal laser scanning flowmetry (Heidelberg Retinal Flowmeter) in the neuroretinal rim inside of the optic disc, and in the retina close to the temporal and nasal border of the optic nerve head was performed. RESULTS: Mean confocal laser scanning flowmetric measurements in the neuroretinal rim, temporal parapapillary retina, and nasal parapapillary retina were significantly (P<0.03) lower in the normal-pressure glaucoma group than in the age-adjusted control group. Correspondingly, mean confocal laser scanning flowmetric measurements within the neuroretinal rim decreased significantly, with relatively low correlation coefficients, decreasing neuroretinal rim area (P = 0.016; correlation coefficient r2 = 0.026), and increasing mean visual field defect (P = 0.011; r2 = 0.029). Measurements were statistically independent of alpha zone (P = 0.38; r2 = 0.004) and beta zone (P = 0.57; r2 = 0.002) of parapapillary atrophy. CONCLUSIONS: Confocal laser scanning flowmetric measurements within the neuroretinal rim were lower in eyes with normal-pressure glaucoma than in age-matched normal eyes. Confocal laser scanning flowmetric measurements decrease with increasing glaucomatous optic nerve damage. There is, however, a marked variability preventing a clear relationship between stage of glaucoma and decrease in confocal laser scanning flowmetric measurements. The correlation between parapapillary atrophy and confocal laser scanning flowmetric measurements is not statistically significant in normal-pressure glaucoma.

Aged↗

PubMed2003

New glaucoma classification method based on standard Heidelberg Retina Tomograph parameters by bagging classification trees.

PURPOSE: In this article we propose and evaluate nonparametric tree classifiers that can handle non-normal data and a large number of possible predictors using the full set of standard Heidelberg Retina Tomograph measurements for classifying glaucoma. METHODS: The classifiers were trained and tested using standard Heidelberg Retina Tomograph parameters from examinations of 98 subjects with glaucoma and 98 normal subjects of the Erlangen Glaucoma Registry. All patients and control subjects were evaluated by 15 degrees -optic disc stereographs, Heidelberg Retina Tomograph measurements, standard computerized white-in-white perimetry, and 24-hour-intraocular pressure profiles. The subjects were matched by age and sex. Standard classification trees as well as bagged classification trees were used. The classification outcome of the trees was compared with the classification by two published linear discriminant functions based on Heidelberg Retina Tomograph variables with respect to their cross-validated misclassification error. RESULTS: The bagged classification tree had the lowest misclassification error estimate of 14.8% with a sensitivity of 81.6% at a specificity of 88.8%. The cross-validated error rates of the two linear discriminant function procedures were 20.4% (sensitivity 82.6%, specificity 76.7%) and 20.6% (sensitivity 81.4%, specificity 77.3%) for our set of observations. Bagged classification trees were able to reduce the misclassification error of glaucoma classification. CONCLUSIONS: Bagged classification trees promise to be a new and efficient approach for glaucoma classification using morphometric 2- and 3-dimensional data derived from the Heidelberg Retina Tomograph, taking into account all given variables.

Case-Control Studies↗

PubMed2003

Glaucomatous optic disc hemorrhages on confocal scanning laser tomographic images.

PURPOSE: To evaluate the detectability of glaucomatous optic disc hemorrhages by confocal scanning laser tomography. METHODS: The study included 73 eyes of 63 patients, who consecutively showed optic disc hemorrhages on 15 degrees color optic disc photographs taken at baseline or during follow-up examinations and for whom confocal scanning laser tomographic images were additionally available. Of the total number of 92 observed hemorrhages, 51 hemorrhages extended into the parapapillary region and 41 hemorrhages were restricted to the intrapapillary region. The scanning laser tomographic images were searched for the disc hemorrhages already seen on the conventional disc photographs. RESULTS: Using the reflectivity images, 29 (32%) hemorrhages were detected on the scanning laser tomographs. None of the hemorrhages restricted to the intrapapillary region could be seen on the scanning laser tomographs. By evaluating each of the 32 single images of the scanning laser tomographic image series, 44 (48%) of the hemorrhages were identified on at least one single image. The detectability of disc hemorrhages on the scanning laser tomographs depended significantly on their extension into the parapapillary region or their intrapapillary location. Detectability of disc bleedings was statistically independent of the disc quadrant where the hemorrhage was located, width of the bleeding, size of the optic disc, neuroretinal rim, parapapillary atrophy, and type of glaucoma. CONCLUSIONS: Confocal scanning laser tomography is not very suitable for detection or documentation of optic disc hemorrhages in patients with glaucoma.

Adult↗

PubMed2002

[Comparison of precision of the TonoPenXL with the Goldmann and Draeger applanation tonometer in a sitting and recumbent position of the patients -- a clinical study on 251 eyes].

PURPOSE: Comparison of precise intraocular pressure (IOP) measurement with TonoPenXL, Goldmann and Draeger applanation tonometer in a sitting and recumbent position. MATERIAL AND METHODS: The IOP of 251 eyes of 127 consecutive patients (SFB 539) was measured prospectively in a sitting position (1 x Goldmann, 3 x TonoPenXL) and in recumbent position (1 x Draeger, 3 x TonoPen). The mean of three TonoPenXL measurements was only accepted in a 5 % interval. Additionally, corneal ultrasonic pachymetry (Tomey, AL-2000), central corneal power, refractive error, gender and age were registered. RESULTS: The IOP measured with the TonoPenXL was in 92 % in a range of 2 mm Hg from the Goldmann standard. In a vertical position, the IOP TonoPenXL (16.7 +/- 4.5 mm Hg) was 0.2 mm Hg lower than the IOP Goldmann (16.9 +/- 5.1 mm Hg; regression analysis: IOP TonoPenXL = 1.78 + 0.88 IOP Goldmann). In a horizontal position, the IOP TonoPenXL (17.5 +/- 5.0 mm Hg) was 0.5 mm Hg higher as the IOP Draeger (17.0 +/- 5.3 mm Hg; regression analysis: IOP TonoPen = 0.34 + 1.016 IOP Draeger). Using the TonoPenXL, the IOP was 0.8 mm Hg higher in recumbent position than in a sitting position (regression analysis: IOP TonoPen recumbent position = - 2.27 + 1.19 IOP TonoPen sitting position). We found no relationship found between central corneal power, central corneal thickness and IOD measured with the TonoPenXL. CONCLUSIONS: The TonoPenXL is useful for IOP measurement in a sitting and recumbent position. The results are reproducible in 92% with the Goldmann-applanation tonometer. The ophthalmologist has a comfortable measurement and screening tool for consultations or IOP investigation under general anaesthesia.

Adult↗

PubMed2002

Discriminant analysis formulas of optic nerve head parameters measured by confocal scanning laser tomography.

PURPOSE: To evaluate whether discriminant analysis formulas of optic disc variables measured by confocal laser scanning tomography can detect glaucomatous visual field defects, to compare the diagnostic precision of these formulas to detect glaucomatous visual field defects in different types of chronic open-angle glaucoma, and to assess whether gender or refractive error influence the results obtained by the formulas. METHODS: One hundred and sixty-one patients with perimetrically defined glaucomatous optic nerve damage and 194 healthy subjects were recruited. All patients underwent confocal laser scanning tomography of the optic disc. The data were analyzed with three linear discriminant analysis formulas (sectorial, Bathija, and Mikelberg) obtained in sets of data different from those used in the present study. RESULTS: The areas under the receiver-operating characteristic curves of the three formulas and of the cup shape measure as a single parameter ranged from 0.649 to 0.81 in the entire group, and the results did not change when age-matched eyes were considered (0.618-0.812). In each of the glaucoma subgroups with primary open-angle, pseudoexfoliative, and normal-pressure glaucoma, and additionally in the hyperopic, myopic, female, and male subgroups, the sectorial formula had the highest diagnostic precision and the highest correlation coefficients with the visual field indices, followed by the Bathija and Mikelberg formulas, without major differences between the subgroups. All three formulas were more effective than the cup shape measure as a single parameter. CONCLUSION: In the various chronic open-angle glaucomas, the sectorial and Bathija formulas tended to have higher diagnostic precision than the Mikelberg formula and the cup shape measure. Gender and refractive error do not markedly influence the diagnostic precision of the formulas tested. The scores of the formulas are mild indicators of the amount of glaucomatous visual field loss. All three formulas are superior to the single cup shape measure in the detection of glaucomatous optic nerve damage.

Adult↗

PubMed2002

Monitoring glaucoma progression with visual evoked potentials of the blue-sensitive pathway.

PURPOSE: To determine the value of visual evoked potentials with blue-on-yellow pattern stimulation in follow-up of glaucoma. METHODS: This prospective longitudinal concurrent study included a heterogeneous cohort of two groups, perimetric (n = 161) and preperimetric (n = 118), of patients with chronic open-angle glaucoma and 113 healthy control subjects. In the preperimetric glaucoma group, patients showed glaucomatous abnormalities of the optic disc, maximum intraocular pressure higher than 21 mm Hg, and unremarkable computerized visual field examination results. Patients underwent up to three VEP measurements with blue-on-yellow pattern stimulation, as well as qualitative and morphometric evaluation of color stereo optic disc photographs. Mean follow-up time between measurements was 24 months. VEP measurements were separately analyzed in preperimetric subjects, with and without progression of optic nerve damage. Progression of glaucoma was defined as increasing loss of neuroretinal rim. RESULTS: A separate analysis of VEP peak times in patients in the preperimetric group, with and without progression of glaucomatous optic nerve damage, showed no significant difference at baseline but a significant prolongation (P = 0.01) in patients with progressive disease, 2 years before morphologic changes were evident. VEPs in patients with nonprogressive disease were statistically unchanged during the observation period. The perimetric group and both preperimetric groups showed significantly prolonged VEP peak times in comparison with the control group (P < 0.001). CONCLUSIONS: In addition to photographic evaluation to detect glaucomatous disc atrophy, the blue-on-yellow VEP may be an objective electrophysiological tool for monitoring patients with glaucoma, because peak times are significantly associated with progression of optic nerve damage.

Chronic Disease↗