Robert Laemmer

Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Bavaria, Germany

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Publications (14)29.95 Total impact

  • Article: Longitudinal analysis of progression in glaucoma using spectral-domain optical coherence tomography.
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    ABSTRACT: Purpose. To compare the longitudinal loss of RNFL thickness measurements by SD-OCT in normals and glaucoma patients with or without progression concerning optic disc morphology. Methods. 62 eyes, comprising 38 glaucomatous eyes with open angle glaucoma and 24 healthy controls, were included in the study (Erlangen Glaucoma Registry, NTC00494923). All patients were investigated annually over a period of three years by Spectralis SD-OCT measuring peripapillary RNFL thickness. By masked comparative analysis of photographs the eyes were classified into non-progressive and progressive glaucoma cases. Longitudinal loss of RNFL thickness was compared to morphological changes of optic disc morphology. Results. Mixed model analysis of annual OCT scans revealed an estimated annual decrease of the RNFL thickness by 2.12 µm in glaucoma eyes with progression, whereas glaucoma eyes without progression in optic disc morphology lost 1.18 µm per year in RNFL thickness (p = 0.002). The rate of change in healthy eyes was 0.60 µm and thereby also significantly lower than in glaucoma eyes with progression (p < 0.001). The intrasession variability of three successive measurements without head repositioning was 1.5 +- 0.7 µm. The loss of mean RNFL thickness exceeded the intrasession variability in 60% of non-progressive eyes, and in 85 % of progressive eyes after three years. Conclusions. Longitudinal measurements of RNFL thickness using SD-OCT show a more pronounced reduction of RNFL thickness in patients with progression compared to patients without progression in glaucomatous optic disc changes.
    Investigative ophthalmology & visual science 04/2013; · 3.43 Impact Factor
  • Article: Glaucoma Diagnostic Performance of GDxVCC and Spectralis OCT on Eyes With Atypical Retardation Pattern.
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    ABSTRACT: PURPOSE:: To investigate the impact of typical scan score (TSS) on discriminating glaucomatous and healthy eyes by scanning laser polarimetry and spectral domain optical coherence tomography (SD-OCT) in 32 peripapillary sectors. PATIENTS AND METHODS:: One hundred two glaucoma patients and 32 healthy controls underwent standard automated perimetry, 24-hour intraocular pressure profile, optic disc photography, GDxVCC, and SD-OCT measurements. For controls, only very typical scans (TSS=100) were accepted. Glaucoma patients were divided into 3 subgroups (very typical: TSS=100; typical: 99≥TSS≥80, atypical: TSS<80). Receiver operating characteristic curves were constructed for mean retinal nerve fiber layer values, sector data, and nerve fiber indicator (NFI). Sensitivity was estimated at ≥90% specificity to compare the discriminating ability of each imaging modality. RESULTS:: For discrimination between healthy and glaucomatous eyes with very typical scans, the NFI and inferior sector analyses 26 to 27 demonstrated the highest sensitivity at ≥90% specificity in GDxVCC and SD-OCT, respectively. For the typical and atypical groups, sensitivity at ≥90% specificity decreased for all 32 peripapillary sectors on an average by 10.9% and 17.9% for GDxVCC and by 4.9% and 0.8% for SD-OCT. For GDxVCC, diagnostic performance of peripapillary sectors decreased with lower TSS, especially in temporosuperior and inferotemporal sectors (sensitivity at ≥90% specificity decreased by 55.3% and by 37.8% in the atypical group). CONCLUSIONS:: Diagnostic accuracy is comparable for SD-OCT and GDxVCC if typical scans (TSS=100) are investigated. Decreasing TSS is associated with a decrease in diagnostic accuracy for discriminating healthy and glaucomatous eyes by scanning laser polarimetry. NFI is less influenced than the global or sector retinal nerve fiber layer thickness. The TSS score should be included in the standard printout. Diagnostic accuracy of SD-OCT is barely influenced by low TSS.
    Journal of glaucoma 10/2011; · 1.74 Impact Factor
  • Article: Detection of nerve fiber atrophy in apparently effectively treated papilledema in idiopathic intracranial hypertension.
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    ABSTRACT: Since papilledema in idiopathic intracranial hypertension is a passive event not primarily affecting the visual tract, resolution with restitution ad integrum is expected if intracranial pressure is rebalanced. Retinal nerve fiber swelling due to papilledema in the acute phase and possible axon loss after long-lasting elevated intracranial pressure was investigated in a controlled cross-sectional study by scanning laser polarimetry. A cohort of 23 patients with idiopathic intracranial hypertension according to the modified Dandy diagnostic criteria, and 23 controls matched for age and gender were investigated. All patients received neurological and ophthalmologic examination including scanning laser polarimetry (GDx VCC). Patients were divided into groups depending on the presence of a papilledema (group 1) or the regression of the papilledema after initiation of therapy (group 2). Therapy was based on recommendations of the German Society of Neurology. Scanning laser polarimetry showed an increase of nerve fiber thickness in group 1, and a decrease of the nerve fiber thickness in group 2 compared to controls. Ten of 13 patients showed signs of a regional axon loss in the deviation map of the GDx report, and six had a Nerve Fiber Index above 30. All patients with regressive papilledema and coincidence of visual field damage and pale optic disc appearance had a pathologic result in the GDx examination, but only four of ten patients with a pathologic GDx examination showed coincidence of pale optic disc appearance and visual field damage as sign of underlying optic disc atrophy. In patients with apparently effective treatment of clinical symptoms and a regression of papilledema in idiopathic intracranial hypertension, a retinal axon loss was detected by scanning laser polarimetry. Axon loss was even present in patients without clinical evidence of optic nerve atrophy.
    Albrecht von Graæes Archiv für Ophthalmologie 12/2010; 248(12):1787-93. · 2.17 Impact Factor
  • Article: Morphologic and functional glaucomatous change after occurrence of single or recurrent optic disc hemorrhages.
    Albrecht von Graæes Archiv für Ophthalmologie 11/2010; 248(11):1683-4; author reply 1685. · 2.17 Impact Factor
  • Article: Retinal nerve fiber layer thickness in normals measured by spectral domain OCT.
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    ABSTRACT: To determine normal values for peripapillary retinal nerve fiber layer thickness (RNFL) measured by spectral domain Optical Coherence Tomography (SOCT) in healthy white adults and to examine the relationship of RNFL with age, gender, and clinical variables. The peripapillary RNFL of 170 healthy patients (96 males and 74 females, age 20 to 78 y) was imaged with a high-resolution SOCT (Spectralis HRA+OCT, Heidelberg Engineering) in an observational cross-sectional study. RNFL thickness was measured around the optic nerve head using 16 automatically averaged, consecutive circular B-scans with 3.4-mm diameter. The automatically segmented RNFL thickness was divided into 32 segments (11.25 degrees each). One randomly selected eye per subject entered the study. Mean RNFL thickness in the study population was 97.2 ± 9.7 μm. Mean RNFL thickness was significantly negatively correlated with age (r = -0.214, P = 0.005), mean RNFL decrease per decade was 1.90 μm. As age dependency was different in different segments, age-correction of RNFL values was made for all segments separately. Age-adjusted RNFL thickness showed a significant correlation with axial length (r = -0.391, P = 0.001) and with refractive error (r = 0.396, P<0.001), but not with disc size (r = 0.124). Normal RNFL results with SOCT are comparable to those reported with time-domain OCT. In accordance with the literature on other devices, RNFL thickness measured with SOCT was significantly correlated with age and axial length. For creating a normative database of SOCT RNFL values have to be age adjusted.
    Journal of glaucoma 09/2010; 19(7):475-82. · 1.74 Impact Factor
  • Article: In Response:
    Journal of glaucoma 03/2010; 19(3):222-224. · 1.74 Impact Factor
  • Article: Comparison of scanning laser polarimetry and optical coherence tomography in quantitative retinal nerve fiber assessment.
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    ABSTRACT: To investigate the relationship between retinal nerve fiber layer (RNFL) measurements in corresponding areas obtained with scanning laser polarimetry and optical coherence tomography and to compare their discriminating ability in the diagnosis of preperimetric and perimetric glaucoma. Three hundred eighty-six subjects-57 healthy controls, 145 ocular hypertensive patients, 89 with preperimetric glaucoma, and 95 with perimetric glaucoma-were recruited from the Erlangen Glaucoma Registry. Perimetry, 24-hours intraocular pressure profile, stereographic optic disc slides, optical coherence tomography StratusOCT, and scanning laser polarimetry GDx VCC (Carl Zeiss Meditec, Inc, Dublin, CA) were performed in all patients. Receiver operating characteristic (ROC) curves were constructed for mean RNFL values, sector data, and indices. Sensitivity was estimated at >or=90% and >or=80% of specificity to compare the discriminating ability of each imaging modality. For discrimination between glaucomatous and healthy eyes in GDx VCC the nerve fiber index demonstrated the largest area under the ROC curve (AUROC) (0.962+/-0.013), whereas in StratusOCT the largest AUROC (0.986+/-0.006) was found in the inferior quadrant. For preperimetric glaucoma detection the nerve fiber index achieved the largest AUROC (0.783+/-0.037). In contrast, the total RNFL average obtained using StratusOCT showed the largest AUROC (0.904+/-0.025). Bland-Altman plots showed good agreement between both instruments. Both the GDx VCC and StratusOCT demonstrate increasing RNFL loss with advanced glaucomatous damage and were comparable in the diagnosis of perimetric glaucoma. Preperimetric glaucomatous damage may be better assessed by StratusOCT.
    Journal of glaucoma 04/2009; 19(2):83-94. · 1.74 Impact Factor
  • Article: Correlation between local glaucomatous visual field defects and loss of nerve fiber layer thickness measured with polarimetry and spectral domain OCT.
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    ABSTRACT: To study the correlation between local perimetric field defects and glaucoma-induced thickness reduction of the nerve layer measured in the peripapillary area with scanning laser polarimetry (SLP) and spectral domain optical coherence tomography (SOCT) and to compare the results with those of a theoretical model. The thickness of the retinal nerve fiber layer was determined in 32 sectors (11.25 degrees each) by using SLP with variable cornea compensation (GDxVCC; Laser Diagnostics, San Diego, CA) and the newly introduced high-resolution SOCT (Spectralis; Heidelberg Engineering, Heidelberg, Germany). Eighty-eight healthy subjects served as control subjects, to determine the thickness deviation in patients with glaucoma. The relationship between glaucomatous nerve fiber reduction and visual field losses was calculated in six nerve fiber bundle-related areas. Sixty-four patients at different stages of open-angle glaucoma and 26 patients with ocular hypertension underwent perimetry (Octopus G1; Haag-Streit, Köniz, Switzerland) and measurements with the two morphometric techniques. Sector-shaped analyses between local perimetric losses and reduction of the retinal nerve fiber layer thickness showed a significant association for corresponding areas except for the central visual field in SLP. Correlation coefficients were highest in the area of the nasal inferior visual field (SOCT, -0.81; SLP, -0.57). A linear model describes the association between structural and functional damage. Localized perimetric defects can be explained by reduced nerve fiber layer thickness. The data indicate that the present SOCT is useful for determining the functional-structural relationship in peripapillary areas and that association between perimetric defects and corresponding nerve fiber losses is stronger for SOCT than for the present SLP. (ClinicalTrials.gov number, NCT00494923.).
    Investigative ophthalmology & visual science 02/2009; 50(5):1971-7. · 3.43 Impact Factor
  • Article: Measuring contrast sensitivity in normal subjects with OPTEC 6500: influence of age and glare.
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    ABSTRACT: The purpose of this study was to develop age-related curves for contrast sensitivity (CS) in normal subjects under day and night conditions with and without glare. Sixty-one healthy eyes from 61 subjects were measured with the OPTEC(R) 6500 P under day and night conditions (luminance levels: 85 cd/m(2) and 3.0 cd/m(2) with and without glare; spatial frequencies: 1.5, 3, 6, 12 and 18 cycles/degree). A reliability analysis with five repeated measurements of six persons on 4 days was performed to examine the repeatability. The influence of age on contrast sensitivity, forward and backward scatter was examined by means of linear regression. Contrast sensitivity was significantly reduced under night conditions with glare, whereas glare had less influence under daylight illumination. Mean reliability coefficients are 0.87 (day), 0.77 (day with glare), 0.69 (night) and 0.81 (night with glare), which suggests sufficient retest reliability of the device. Regression analyses showed a highly significant influence of age, but the variance of the measurement values is not explained by age alone. The coefficients of determination for the regression of area under the log contrast sensitivity function (AULCSF) on age are 0.33 (photopic), 0.34 (photopic with glare), 0.29 (mesopic) and 0.36 (mesopic with glare, p < 0.0001 in all cases). A significant relationship between age, CS and scatter was confirmed in our study. The results provide baseline values for the examination of patients with different diseases in which contrast sensitivity is impaired (such as glaucoma, cataracts and amblyopia) and might be useful in studies of roadworthiness or in investigation of the impact of intraocular lenses.
    Albrecht von Graæes Archiv für Ophthalmologie 12/2007; 245(12):1805-14. · 2.17 Impact Factor
  • Article: Quantification of neuroretinal rim loss using digital planimetry in long-term follow-up of normals and patients with ocular hypertension.
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    ABSTRACT: The purpose of this study was to investigate if digital planimetry is appropriate for quantification of neuroretinal rim loss in patients with ocular hypertension (OHT) and if there is an age-related neuroretinal rim loss in normals. Fifty-six patients with OHT without optic disc change, 13 patients with OHT and conversion to early glaucoma during follow-up and 42 age-matched controls were recruited from the Erlangen Glaucoma Registry. Annually, all patients underwent complete ophthalmologic examination including detailed diagnostic testing concerning glaucoma. Gold standard for morphologic evaluation of the optic nerve head was the semiquantitative 2-dimensional-method described by Jonas. Optic disc images from baseline and after 5 or 10 years follow-up were used for digital planimetry. Optic disc area and cup area were measured using commercial software: Soft Imaging System analysis. The investigator was masked for diagnosis and time point of examination. Mean neuroretinal rim loss was 0.36% per year in controls, 0.54% per year in patients with OHT without progressive disease, and 0.95% per year in OHT and conversion. Neuroretinal rim loss was highest in the group of OHT with conversion to early glaucoma during follow-up. In the control group we detected a very low mean neuroretinal rim loss during 10-year follow-up. In ocular hypertensive patients without progressive disease mean neuroretinal rim loss was approximately twice compared with normals.
    Journal of Glaucoma 09/2007; 16(5):430-6. · 1.78 Impact Factor
  • Article: Measurement of autofluorescence in the parapapillary atrophic zone in patients with ocular hypertension.
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    ABSTRACT: The purpose of the study was to investigate area and intensity of parapapillary autofluorescence in patients with ocular hypertension and controls. 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. 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). 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.
    Albrecht von Graæes Archiv für Ophthalmologie 01/2007; 245(1):51-8. · 2.17 Impact Factor
  • Article: Influence of optic disc size on parameters of retinal nerve fiber analysis with laser scanning polarimetry.
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    ABSTRACT: The aim of the study was to evaluate the influence of optic disc size on the variables of laser scanning polarimetry (GDx). 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. 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. 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.
    Albrecht von Graæes Archiv für Ophthalmologie 05/2006; 244(5):603-8. · 2.17 Impact Factor
  • Article: Visualization of changes of the iris configuration after peripheral laser iridotomy in primary melanin dispersion syndrome using optical coherence tomography.
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    ABSTRACT: Pigment or melanin dispersion syndrome is characterized by radial iris transillumination defects, retrocorneal Krukenberg spindle, and dense trabecular pigmentation. Reverse pupillary block has been presumed as one possible pathogenetic mechanism for backward bowing of the iris leading to iris-zonular rubbing and distribution of melanin granules in the anterior chamber. Laser iridotomy is recommended as a treatment to prevent further melanin dispersion and development of pigmentary glaucoma. The effect of Nd:YAG laser iridotomy as a prophylactic and potentially causal treatment in melanin dispersion syndrome can be easily visualized by optical coherence tomography as a fast and noncontact procedure.
    Journal of glaucoma 17(7):569-70. · 1.74 Impact Factor
  • Article: Influence of glaucomatous damage and optic disc size on glaucoma detection by scanning laser tomography.
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    ABSTRACT: To investigate the impact of glaucomatous damage and optic disc size on different automated Heidelberg Retina Tomograph classifications for discriminating glaucoma and healthy controls. Two hundred seventy-three glaucoma patients and 276 healthy controls were recruited from the Erlangen Glaucoma Registry. Standard static white on white perimetry, 24-hour intraocular pressure profile, stereographic optic disc slides, and scanning laser tomography were performed in all patients and controls. The effect of glaucoma stage and disc size on the diagnostic accuracy was evaluated using receiver operating characteristic curves. Results of the Glaucoma Probability Score were compared with other recently described multivariate classifications. Areas under the receiver operating characteristic curves for discrimination between glaucoma and healthy eyes of the overall classification by Glaucoma Probability Score, Moorfields regression analysis, Bathija, Iester, Mikelberg, and Mardin increased from 0.71, 0.65, 0.70, 0.67, 0.65, and 0.63 for early glaucoma (Jonas: stage I) to 0.96, 0.95, 0.94, 0.94, 0.92, and 0.88 for advanced glaucomatous damage (Jonas: stage IV). Best performance of discrimination between glaucoma and healthy eyes using area under the receiver operating characteristic curve's were observed for medium-sized discs (2.1 to 2.49 mm) and worst performance for large optic discs (>3.1 mm). Glaucoma Probability Score classification was superior to other investigated classifications in most of the investigated subgroups. The diagnostic accuracy of all classifications depends on the optic disc size and the glaucoma stage. Glaucoma Probability Score showed a better diagnostic performance than Moorfields regression analysis and was similar to that of Bathija.
    Journal of glaucoma 18(5):385-9. · 1.74 Impact Factor