Research Topics
| Martin HammerSummaryAffiliation: Friedrich Schiller University Country: Germany Publications
|
Detail Information
Publications
Retinal vessel oxygen saturation under flicker light stimulation in patients with nonproliferative diabetic retinopathyMartin Hammer
Department of Ophthalmology, University of Jena, Jena, Germany
Invest Ophthalmol Vis Sci 53:4063-8. 2012..We investigated the response of retinal vessel diameters and oxygen saturation to flicker light stimulation of neuronal activity in patients with diabetic retinopathy...
[Spectral separation in ocular fundus autofluorescence images in patients suffering from age-related macular degeneration]M Hammer
Augenklinik, Friedrich Schiller Universitat, Jena
Ophthalmologe 101:1189-93. 2004..Alterations in the intrinsic ocular fundus fluorescence are under discussion particularly in connection with age-related macular degeneration. However, further knowledge of the chemical substrate of fluorescence is necessary...- Sodium fluorescein as a retinal pH indicator?Martin Hammer
Department of Ophthalmology, University of Jena, Bachstr 18, 07740 Jena, Germany
Physiol Meas 26:N9-12. 2005..Further investigations have to clarify whether the accuracy of the measurement at the fundus in vivo is sufficient... - Retinal pigment epithelium cell damage by A2-E and its photo-derivativesMartin Hammer
University of Jena, Department of Ophthalmology, Jena, Germany
Mol Vis 12:1348-54. 2006..Illumination of A2-E with short wavelength light results in isomerization, photooxidation, as well as photolysis. Cytotoxic intermediates (free oxygen radicals) and reaction products (peroxides) are involved in this process... - Ocular fundus auto-fluorescence observations at different wavelengths in patients with age-related macular degeneration and diabetic retinopathyMartin Hammer
Department of Ophthalmoloy, University of Jena, Bachstr 18, 07740, Jena, Germany
Graefes Arch Clin Exp Ophthalmol 246:105-14. 2008..The distinct fluorescence spectra of lipofuscin and AGE enable their differentiation in multispectral fundus fluorescence imaging... - Intrinsic tissue fluorescence in an organotypic perfusion culture of the porcine ocular fundus exposed to blue light and free radicalsMartin Hammer
Department of Ophthalmology, University of Jena, Bachstr 18, 07740 Jena, Germany
Graefes Arch Clin Exp Ophthalmol 246:979-88. 2008..Thus, we developed an organotypic perfusion culture model of the porcine ocular fundus, generating lipofuscin under exposure to blue light and hydrogen peroxide... - Retinal vessel oximetry-calibration, compensation for vessel diameter and fundus pigmentation, and reproducibilityMartin Hammer
University of Jena, Department of Ophthalmology, Jena, Germany
J Biomed Opt 13:054015. 2008..It is able to measure the oxygen saturation in retinal branch vessels with reproducibility and sensitivity suitable for clinical investigations... - Diabetic patients with retinopathy show increased retinal venous oxygen saturationMartin Hammer
Department of Ophthalmology, University of Jena, Bachstr 18, 07740, Jena, Germany
Graefes Arch Clin Exp Ophthalmol 247:1025-30. 2009..Longstanding diabetes mellitus results in a disturbed microcirculation. A new imaging oximeter was used to investigate the effect of this disturbance on retinal vessel oxygen saturation... - Retinal venous oxygen saturation increases by flicker light stimulationMartin Hammer
Department of Ophthalmology, University of Jena, Jena, Germany
Invest Ophthalmol Vis Sci 52:274-7. 2011..Oxygen supply may be the target of the regulation of retinal blood flow. Thus, the oxygen saturation (SO(2)) in retinal arterioles and venules was investigated along with their diameters... - [Determination of the concentration distribution of macular pigment from reflection and fluorescence images]M Hammer
Augenklinik, FSU, Jena
Ophthalmologe 100:611-7. 2003..Therefore, we investigated a simple method to determine the xanthophyll concentration at the fundus which is suitable for patient screening... - [Intrastomal refractive surgery with ultra-short laser pulses. Results from initial in vitro experiments]M Hammer
Augenklinik der FSU Jena, Germany
Ophthalmologe 99:756-60. 2002..To investigate the possibilities and techniques for intrastromal ablation of the cornea by the use of ultra-short laser pulses... - Quantitative reflection spectroscopy at the human ocular fundusMartin Hammer
Department of Ophthalmology, Friedrich Schiller University, Jena, Germany
Phys Med Biol 47:179-91. 2002..The concentration values found in 12 healthy subjects are in excellent agreement with published data. In individual cases of pathologic fundus alterations, possible benefits to the ophthalmologic diagnostics are demonstrated... - A simple algorithm for in vivo ocular fundus oximetry compensating for non-haemoglobin absorption and scatteringMartin Hammer
Department of Ophthalmology, Friedrich Schiller University, Jena, Germany
Phys Med Biol 47:N233-8. 2002..The oxygen saturation values were compared to measurements of the same samples at a laboratory haemoximeter. The mean deviation was found to be 2.65%... - A scattering phase function for blood with physiological haematocritM Hammer
University of Jena, Department of Ophthalmology, Germany
Phys Med Biol 46:N65-9. 2001..The results show that a Henyey-Greenstein phase function with an anisotropy factor of 0.972 is an adequate approximation for the effective scattering phase function of whole blood with high haematocrit at a wavelength of 514 nm... - [The optics of retinal blood vessels and their significance for scanning laser Doppler flowmetry]M Hammer
Klinikum der Friedrich Schiller Universitat Jena, Klinik fur Augenheilkunde, Bachstrasse 18, 07740 Jena
Ophthalmologe 98:844-7. 2001.... - Light paths in retinal vessel oxymetryM Hammer
Department of Ophthalmology, University Jena, Germany
IEEE Trans Biomed Eng 48:592-8. 2001..However, both components are in the same order of magnitude. This has to be considered in the calculation of the oxygen saturation of blood in retinal vessels from their reflection spectra... 
Time-resolved autofluorescence imaging of human donor retina tissue from donors with significant extramacular drusenDietrich Schweitzer
Department of Ophthalmology, University Hospital Jena, Jena, Germany
Invest Ophthalmol Vis Sci 53:3376-86. 2012..We performed time-resolved autofluorescence measurements on fundus samples from a donor with significant extramacular drusen...- In vivo measurement of time-resolved autofluorescence at the human fundusDietrich Schweitzer
University of Jena, Department of Experimental Ophthalmology, Bachstr 18, 07740 Jena, Germany
J Biomed Opt 9:1214-22. 2004..Such lifetime clusters of a 20 deg macular field of a young healthy subject and of a patient suffering from dry age-related macular degeneration overlap only partially with tau2-tau1 clusters of lipofuscin... - A new method for the measurement of oxygen saturation at the human ocular fundusD Schweitzer
Department of Experimental Ophthalmology, University of Jena, Germany
Int Ophthalmol 23:347-53. 2001..First measurements of the oxygen saturation in age-related macular degeneration point to partly different pathological changes of the retinal microcirculation in dry and in wet AMD... - [Comparison of parameters of time-resolved autofluorescence between healthy subjects and patients suffering from early AMD]D Schweitzer
Bereich Experimentelle Ophthalmologie, Augenklinik der FSU Jena, Deutschland
Ophthalmologe 106:714-22. 2009..A fluorescence lifetime mapper (FLM) was tested for quantitative estimation of early alterations in age-related macular degeneration (AMD) which are assumed to be in cellular metabolism... - [Haemoglobin oxygenation of retinal vessels in branch retinal artery occlusions over time and correlation with clinical outcome]S Gehlert
Klinik fur Augenheilkunde, Universitatsklinikum Jena, Jena
Klin Monbl Augenheilkd 227:976-80. 2010..Purpose of these study was the evaluation of a new method for the measurement of haemoglobin oxygenation in retinal vessels. Patients with branch retinal artery occlusion have been measured before and after a rheological therapy... - [Time-resolved autofluorescence in retinal vascular occlusions]D Schweitzer
Bereich Experimentelle Ophthalmologie, Augenklinik der FSU Jena, Bachstraße 18, Jena, Germany
Ophthalmologe 107:1145-52. 2010..In branch retinal artery occlusion, metabolic changes can be compared with normal tissue... - [Time-correlated measurement of autofluorescence. A method to detect metabolic changes in the fundus]D Schweitzer
Augenklinik der FSU Jena, Bereich Experimentelle Ophthalmologie, Germany
Ophthalmologe 99:774-9. 2002..5 ns were detected in the parapapillary area. By evaluating the frequency of lifetimes, lipofuscin, free FAD, and collagen are probably detectable. Comparative measurements were performed in fundus specimens and on free FAD... - Non-invasive measurement of the concentration of melanin, xanthophyll, and hemoglobin in single fundus layers in vivo by fundus reflectometryM Hammer
University of Jena, Department of Ophthalmology, Germany
Int Ophthalmol 23:279-89. 2001..The concentration values found in 12 healthy subjects are in excellent agreement with literature data. In single cases of pathologic fundus alterations possible benefits to the ophthalmologic diagnostics is demonstrated... - [Change of retinal oxygen saturation in healthy subjects and in early stages of diabetic retinopathy during breathing of 100% oxygen]D Schweitzer
Experimentelle Ophthalmologie, Augenklinik der FSU Jena
Klin Monbl Augenheilkd 224:402-10. 2007.... - Towards metabolic mapping of the human retinaD Schweitzer
Department of Experimental Ophthalmology, University of Jena, Germany
Microsc Res Tech 70:410-9. 2007..Taking into account the transmission of the ocular media, the excitation of NADH is unlikely at the fundus... - [Limits of the confocal laser-scanning technique in measurements of time-resolved autofluorescence of the ocular fundus]D Schweitzer
Experimentelle Ophthalmologie, Augenklinik der Friedrich Schiller Universität Jena
Biomed Tech (Berl) 50:263-7. 2005..It was to be examined, to what extent these measurements are influenced through the auto-fluorescence of the crystalline lens... - [Fundus spectrometry in age-related maculopathy]D Schweitzer
FSU Jena, Klinik fur Augenheilkunde, Bereich Experimentelle Ophthalmologie, Jena
Klin Monbl Augenheilkd 222:396-408. 2005..The detection of autofluorescence of redox-pairs of coenzymes results in information about metabolic states at the cellular level, and might make possible an early detection of age-related changes when they are still reversible... - [Objective determination of optical density of xanthophyll after supplementation of lutein]D Schweitzer
Bereich Experimentelle Ophthalmologie, Augenklinik der Friedrich Schiller Universität Jena
Ophthalmologe 99:270-5. 2002..Most methods applied for the determination of the macular pigment require the co-operation of the proband and the ability for foveal fixation... - [Alterations in autofluorescence decay time in the fundus after oxygen provocation]D Schweitzer
Bereich Experimentelle Ophthalmologie, Augenklinik der FSU Jena
Ophthalmologe 101:66-72. 2004..Therefore, it was investigated whether the autofluorescence of co-enzymes is detectable in the living fundus... - In vivo measurement of the oxygen saturation of retinal vessels in healthy volunteersD Schweitzer
Augenklinik, Friedrich Schiller Universitat Jena, Germany
IEEE Trans Biomed Eng 46:1454-65. 1999..The utilization of oxygen in the temporal quadrants (inferior: 39.4 +/- 10.4%) is significantly (p = 0.05) higher than in the nasal quadrants (inferior: 31.3 +/- 6.7%)... - Basic investigations for 2-dimensional time-resolved fluorescence measurements at the fundusD Schweitzer
Department of Experimental Ophthalmology, University of Jena, Germany
Int Ophthalmol 23:399-404. 2001..emission 450-600 nm) as a putative precursor of lipofuscin in age-related macular degeneration [11], a light source for pulses in the range of about 50 ps is required...