Martin Hammer

Summary

Affiliation: Friedrich Schiller University
Country: Germany

Publications

  1. doi request reprint Retinal vessel oxygen saturation under flicker light stimulation in patients with nonproliferative diabetic retinopathy
    Martin Hammer
    Department of Ophthalmology, University of Jena, Jena, Germany
    Invest Ophthalmol Vis Sci 53:4063-8. 2012
  2. ncbi request reprint 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
  3. ncbi request reprint [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
  4. ncbi request reprint Ocular fundus auto-fluorescence observations at different wavelengths in patients with age-related macular degeneration and diabetic retinopathy
    Martin Hammer
    Department of Ophthalmoloy, University of Jena, Bachstr 18, 07740, Jena, Germany
    Graefes Arch Clin Exp Ophthalmol 246:105-14. 2008
  5. ncbi request reprint [Determination of the concentration distribution of macular pigment from reflection and fluorescence images]
    M Hammer
    Augenklinik, FSU, Jena
    Ophthalmologe 100:611-7. 2003
  6. doi request reprint Intrinsic tissue fluorescence in an organotypic perfusion culture of the porcine ocular fundus exposed to blue light and free radicals
    Martin Hammer
    Department of Ophthalmology, University of Jena, Bachstr 18, 07740 Jena, Germany
    Graefes Arch Clin Exp Ophthalmol 246:979-88. 2008
  7. ncbi request reprint [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
  8. ncbi request reprint A simple algorithm for in vivo ocular fundus oximetry compensating for non-haemoglobin absorption and scattering
    Martin Hammer
    Department of Ophthalmology, Friedrich Schiller University, Jena, Germany
    Phys Med Biol 47:N233-8. 2002
  9. doi request reprint Retinal vessel oximetry-calibration, compensation for vessel diameter and fundus pigmentation, and reproducibility
    Martin Hammer
    University of Jena, Department of Ophthalmology, Jena, Germany
    J Biomed Opt 13:054015. 2008
  10. doi request reprint Diabetic patients with retinopathy show increased retinal venous oxygen saturation
    Martin Hammer
    Department of Ophthalmology, University of Jena, Bachstr 18, 07740, Jena, Germany
    Graefes Arch Clin Exp Ophthalmol 247:1025-30. 2009

Detail Information

Publications33

  1. doi request reprint Retinal vessel oxygen saturation under flicker light stimulation in patients with nonproliferative diabetic retinopathy
    Martin 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...
  2. ncbi request reprint 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...
  3. ncbi request reprint [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...
  4. ncbi request reprint Ocular fundus auto-fluorescence observations at different wavelengths in patients with age-related macular degeneration and diabetic retinopathy
    Martin 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...
  5. ncbi request reprint [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...
  6. doi request reprint Intrinsic tissue fluorescence in an organotypic perfusion culture of the porcine ocular fundus exposed to blue light and free radicals
    Martin 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...
  7. ncbi request reprint [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...
  8. ncbi request reprint A simple algorithm for in vivo ocular fundus oximetry compensating for non-haemoglobin absorption and scattering
    Martin 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%...
  9. doi request reprint Retinal vessel oximetry-calibration, compensation for vessel diameter and fundus pigmentation, and reproducibility
    Martin 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...
  10. doi request reprint Diabetic patients with retinopathy show increased retinal venous oxygen saturation
    Martin 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...
  11. doi request reprint Retinal venous oxygen saturation increases by flicker light stimulation
    Martin 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...
  12. ncbi request reprint Quantitative reflection spectroscopy at the human ocular fundus
    Martin 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...
  13. ncbi request reprint [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
    ....
  14. ncbi request reprint Light paths in retinal vessel oxymetry
    M 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...
  15. ncbi request reprint A scattering phase function for blood with physiological haematocrit
    M 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...
  16. ncbi request reprint Retinal pigment epithelium cell damage by A2-E and its photo-derivatives
    Martin 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...
  17. ncbi request reprint Long term effects of lutein, zeaxanthin and omega-3-LCPUFAs supplementation on optical density of macular pigment in AMD patients: the LUTEGA study
    Jens Dawczynski
    Department of Ophthalmology, University Hospital Leipzig, Liebigstrasse 10 14, 04103, Leipzig, Germany
    Graefes Arch Clin Exp Ophthalmol 251:2711-23. 2013
    ....
  18. pmc Time-resolved autofluorescence imaging of human donor retina tissue from donors with significant extramacular drusen
    Dietrich 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...
  19. ncbi request reprint In vivo measurement of time-resolved autofluorescence at the human fundus
    Dietrich 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...
  20. ncbi request reprint A new method for the measurement of oxygen saturation at the human ocular fundus
    D 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...
  21. ncbi request reprint [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...
  22. ncbi request reprint Non-invasive measurement of the concentration of melanin, xanthophyll, and hemoglobin in single fundus layers in vivo by fundus reflectometry
    M 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...
  23. doi request reprint [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...
  24. doi request reprint [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...
  25. doi request reprint [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...
  26. ncbi request reprint In vivo measurement of the oxygen saturation of retinal vessels in healthy volunteers
    D 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%)...
  27. ncbi request reprint [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...
  28. ncbi request reprint [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...
  29. ncbi request reprint [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...
  30. ncbi request reprint [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
    ....
  31. ncbi request reprint Towards metabolic mapping of the human retina
    D 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...
  32. ncbi request reprint [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...
  33. ncbi request reprint Basic investigations for 2-dimensional time-resolved fluorescence measurements at the fundus
    D 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...