@article{Koop,
   author = {Koop, N. and Wirbelauer, C. and Tüngler, A. and Geerling, G. and Bastian, G. O. and Brinkmann, R},
   title = {Thermische Schädigung des Hornhautendothels bei der Dioden-Laserthermokeratoplastik.},
   journal = {Ophthalmologe},
   volume = {96},
   pages = {392-397},
   year = {1999},
   type = {Journal Article}
}

@article{Brinkmann1998,
   author = {Brinkmann, R and Koop, N. and Kamm, K. and Geerling, G. and Kampmeier, J. and Birngruber, R.},
   title = {Laser Thermokeratoplastik: eine in vitro- und in vivo-Studie mit kontinuierlich emittierender Laserdiode im mittleren IR-Spektralbereich.},
   journal = {Laser in der Medizin, Proc. Laser 97},
   pages = {412-416},
   year = {1998},
   type = {Journal Article}
}

@article{Eichenauer,
   author = {Eichenauer, Rolf H. and Huettmann, Gereon and Woermer, Stephan and Koop, Norbert and Beyer, Wolfgang and Jocham, Dieter},
   title = {New balloon catheter system used for PDT in the human urinary bladder: accuracy of light distribution},
   pages = {138-144},
   note = {10.1117/12.308141},
   abstract = {Photodynamic therapy (PDT) may provide a new approach for treatment of patients with superficial transitional carcinoma and carcinoma in situ of the bladder. The light applicator for the bladder wall (Rusch) is constructed as a balloon catheter with two concentric balloons. A new PDT applicator (Rusch) was assessed for the homogeneity and accuracy of irradiation during PDT. In an in-vitro experiment with 17 freshly harvested porcine bladders the fluence rate was measured locally with isotropic detectors. The results were compared to the light fluence detected by the PDT applicator. The increase of the fluence rate (beta) inside the bladders due to back scattering ranged between 5.3 and 7.0 with an average of 6.2. Local variations of the fluence rate in the spherical bladders were also smaller than 15%. Therefore it is concluded, that a homogeneous and accurate irradiation during PDT is possible. Blood between the outer balloon and the bladder wall reduces the local fluence rate strongly and should to be avoided. Also larger air bubbles in the applicator can lead to an inhomogeneous light distribution. In regular application the presented new catheter system provides accurate and easy light dosimetry during PDT of the bladder. Attention had to be paid to a continuous flushing of the space between balloon and bladder wall in order to prevent the accumulation of urine and blood. To avoid a malfunction of the system and large errors in light dosimetry and application, it is advisable to monitor the measured light dosage and the shape of the balloon using ultrasonography during PDT.},
   year = {1998}
}

@article{Brinkmann1998,
   author = {Brinkmann, R. and Koop, N. and Geerling, G. and Kampmeier, J. and Borcherding, S. and Kamm, K. and Birngruber, R.},
   title = {Diode laser thermokeratoplasty: application strategy and dosimetry},
   journal = {J Cataract Refract Surg},
   volume = {24},
   number = {9},
   pages = {1195-207},
   note = {0886-3350 (Print)
Journal Article
Research Support, Non-U.S. Gov't},
   abstract = {PURPOSE: To investigate suitable application parameters for efficient hyperopic correction by laser thermokeratoplasty (LTK) using mid-infrared laser diodes. SETTING: Medical Laser Center Lubeck, Lubeck, Germany. METHOD: A tunable continuous-wave laser diode in the spectral range between 1.845 and 1.871 microns was used. Transmitted by waveguides, the laser energy was used to induce coagulations on freshly enucleated porcine eyes to increase corneal curvature. The coagulations were equidistantly applied by a fiber-cornea contact and a noncontact focusing device that were adjusted on a ring concentric to the corneal apex. Different laser parameters and application geometries were evaluated. Refractive changes were measured by computer-assisted corneal topography before and after treatment. Polarization light microscopy and temperature calculations were used to analyze the coagulations. RESULTS: Because of the tunability of the laser diode, the influence of the corneal absorption coefficient (between 0.9 and 1.6 mm-1) on the refractive change could be measured. A laser power between 125 and 200 mW was adequate to achieve refractive changes up to 10.0 diopters. In the preferable focusing device, the refractive change increased almost logarithmically with the irradiation time up to 15 seconds. The number of coagulations on a fixed application ring showed no significant influence on refractive change; however, it showed an almost linear decrease with increasing ring diameter from 5.0 to 10.0 mm. Histological analysis revealed 3 stages of thermal damage. CONCLUSION: Diode LTK provided defined and uniform coagulations when using a well-adapted focusing device, resulting in sufficient refractive change. The results indicate that diode LTK is superior to pulsed holmium LTK.},
   keywords = {Absorption
Animals
Cornea/pathology/physiopathology/*surgery
Hyperopia/pathology/physiopathology/*surgery
Laser Coagulation/*methods
Microscopy, Polarization
Refraction, Ocular
Swine},
   year = { 1998}
}

@article{Koop1997,
   author = {Koop, Norbert and Langholz, Michael and Birngruber, Reginald and Geerling, Gerd and Bastian, Gerd-Otto},
   title = {Vergleichende Untersuchungen verschiedener kornealer Topographiemeßgeräte},
   journal = {Der Ophthalmologe},
   volume = {94},
   number = {2},
   pages = {120-126},
   ISSN = {1433-0423},
   url = {http://dx.doi.org/10.1007/s003470050092},
   year = {1997},
   type = {Journal Article}
}

@article{Koop1997,
   author = {Koop, N. and Langholz, M. and Birngruber, R. and Geerling, G. and Bastian, G. O.},
   title = {Comparative evaluation of different corneal topographical devices},
   journal = {Ophthalmologe},
   volume = {94},
   number = {2},
   pages = {120-126},
   note = {Yp129
Times Cited:0
Cited References Count:25},
   abstract = {Purpose: It is difficult to measure the topography of the cornea with high resolution and visualize it on a map displaying refraction. This is demonstrated by the ongoing improvement and further development of different methods and by the fact that users of these techniques are not always satisfied.
Materials and methods: Five different ring projectors were compared. Spherical and aspherical ball standards were used to measure the standard deviation of the refraction of the system. A patient group of eight people with healthy eyes was used to compare the measurement accuracy and operational errors. Some patients were also measured after cataract surgery. The lateral and axial range of the devices was determined.
Results: The measurement accuracy for bail stand ards for the five devices was below 1/8 D. For the in vivo case in the control group it was below 1/4 D for four devices. Furthermore, the reproducibility of the results, the accuracy of angle determination and the influence of mechanical and optical design will be discussed. The study demonstrates applications and limits of this measurement method.},
   keywords = {placido-disk
corneal topography
refractive power
videokeratoscope
accuracy
system
reproducibility},
   ISSN = {0941-293X},
   DOI = {DOI 10.1007/s003470050092},
   url = {<Go to ISI>://WOS:000071245600008},
   year = {1997},
   type = {Journal Article}
}

@article{Koop1997,
   author = {Koop, Norbert and Brinkmann, Ralf and Lankenau, Eva and Flache, Stefan and Engelhardt, Ralf and Birngruber, Reginald},
   title = {Optische Kohärenztomographie der Kornea und des vorderen Augenabschnitts},
   journal = {Der Ophthalmologe},
   volume = {94},
   number = {7},
   pages = {481-486},
   ISSN = {1433-0423},
   url = {http://dx.doi.org/10.1007/s003470050143},
   year = {1997},
   type = {Journal Article}
}

@article{Asiyo-Vogel1997,
   author = {Asiyo-Vogel, M. N. and Koop, N. and Brinkmann, R. and Engelhardt, R. and Eggers, R. and Birngruber, R. and Vogel, A.},
   title = {Evaluation of LTK lesions by optical low coherence tomography (OCT) and polarization microscopy after Sirius-Red staining},
   journal = {Ophthalmologe},
   volume = {94},
   number = {7},
   pages = {487-491},
   note = {Yp140
Times Cited:5
Cited References Count:21},
   abstract = {Background: Information on the extent and degree of the thermal effect produced is of great importance for control of the laser dosage in laser thermokeratoplasty (LTK) and for postoperative follow-up. We investigated on acute LTK effects which information images obtained by optical low coherence tomography (OCT) offer compared to those obtained by polarization microscopy.
Methods: Porcine eyes were irradiated through a 400 mu m quartz fiber using light from a laser diode emitting up to 300 mW at a wavelength of 1.86 mu m. Thermal lesions of varying strength were scanned using an experimental OCT device with about 25 mu m lateral and 20 mu m axial resolution. Histologic evaluation of the scanned areas was done by polarization microscopy after Sirius-Red staining, and similar lesions were also analyzed by TEM.
Results: Both methods differentiated three damage zones: a transition zone, a zone of moderate coagulation, and a central zone of strong coagulation. In the transition zone,increased birefringence was seen in polarization microscopy, which correlated with increased light scattering seen in the DCT images,ln the moderately coagulated zone, a decrease in birefringence was associated with an even stronger increase of the OCT signal, In the central zone,a loss of the fibrillar tissue structure was observed, which led to a complete loss of birefringence and a strong reduction of the OCT signal.
Conclusions: Although OCT does not provide the detailed information on thermal changes of tissue seen by the histologic method, it offers information on the extent and degree of tissue changes without preparation artifacts and provides a non-invasive method of immediate and follow-up control of LTK lesions, A quantitative analysis of changes in corneal thickness and curvature is much simpler than by a slit lamp. Time-resolved measurements of corneal light scattering may be used for on-line control of the laser-light dosage during LTK.},
   keywords = {refractive surgery
laser thermokeratoplasty
collagen denaturation
collagen shrinkage
optical low coherence tomography
polarization microscopy
sirius-red staining
tissue
collagen
eye},
   ISSN = {0941-293X},
   DOI = {DOI 10.1007/s003470050144},
   url = {<Go to ISI>://WOS:000071246700004},
   year = {1997},
   type = {Journal Article}
}

@article{Wirbelauer1997,
   author = {Wirbelauer, C. and Geerling, G. and Koop, N. and Brinkmann, R. and Tungler, A. and Birngruber, R. and Laqua, H.},
   title = {Acute endothelial cell changes after laser thermal keratoplasty with a CW-IR laser diode},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {38},
   number = {4},
   pages = {2516-2516},
   note = {1
Wn186
Times Cited:0
Cited References Count:0},
   ISSN = {0146-0404},
   url = {<Go to ISI>://WOS:A1997WN18602508},
   year = {1997},
   type = {Journal Article}
}

@article{Brinkmann1997,
   author = {Brinkmann, R. and Koop, N. and Kampmeier, J. and Bruhns, A. and AsiyoVogel, M. and Engelhardt, R. and Birngruber, R.},
   title = {Corneal collagen denaturation in laser thermokeratoplasty (LTK)},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {38},
   number = {4},
   pages = {2514-2514},
   note = {1
Wn186
Times Cited:0
Cited References Count:0},
   ISSN = {0146-0404},
   url = {<Go to ISI>://WOS:A1997WN18602506},
   year = {1997},
   type = {Journal Article}
}

@article{Asiyo-Vogel1997,
   author = {Asiyo-Vogel, M and Koop, N and Brinkmann, R and Engelhardt, R and Eggers, R and Birngruber, R and Vogel, A},
   title = {Darstellung von LTK-Läsionen durch optische Kurzkohärenztomographie (OCT) und Polarisationsmikroskopie nach Sirius-Rot-Färbung},
   journal = {Ophthalmologe},
   volume = {94},
   pages = {487-491},
   year = {1997}
}

@article{Geerling1997,
   author = {Geerling, G. and Brinkmann, R. and Koop, N. and Wirbelauer, C. and Laqua, H. and Birngruber, R.},
   title = {Diode-laser thermokeratoplasty - First clinical experiences in human blind eyes},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {38},
   number = {4},
   pages = {2292-2292},
   note = {1
Wn186
Times Cited:0
Cited References Count:0},
   ISSN = {0146-0404},
   url = {<Go to ISI>://WOS:A1997WN18602285},
   year = {1997},
   type = {Journal Article}
}

@article{Koop1997,
   author = {Koop, N. and Brinkmann, R. and Lankenau, E. and Flache, S. and Engelhardt, R. and Birngruber, R.},
   title = {Optical coherence tomography of cornea and anterior segment of the eye},
   journal = {Ophthalmologe},
   volume = {94},
   number = {7},
   pages = {481-486},
   note = {Yp140
Times Cited:34
Cited References Count:19},
   abstract = {Target: The method of optical coherence tomography (OCT) was investigated regarding its suitability and limits for measuring the cornea and the anterior segment of the eye. Furthermore, the stromal expansion of thermally induced lesions in the cornea directly after irradiation was determined within the scope of the laser thermokeratoplasty (LTK).
Material and methods: With the experimental scanning OCT system, x-z sections of the anterior eye segment were made with an optical resolution of about 20 mu m axially and 25 mu m laterally. Freshly enucleated, tonicized porcine eyes were used as model eyes. Thermal lesions were applied with a continuously emitting laser diode (lambda=1.86 mu m) and various radiation parameters, Before and after coagulation, the cornea was viewed from limbus to limbus in a central OCT scan and the individual coagulation source was measured,
Results: Global and local changes of the thickness of the cornea as well as the distance between cornea and lens were measured with high precision. Thermal lesions in their expansion can be clearly presented and matching well with the histologically stained sections, bur are not as exactly defined at the edges due to the limited optical resolution, as known from histological preparations.
Conclusion: With the OCT method quantitative measuring of the anterior eye segment can be performed in vitro and with reduced resolutions also in vivo. Due to the qualitatively good correspondence regarding the dimensions of thermal damage of the cornea with histologically obtained morphometric results,this method can be used for supervision of coagulation directly after LTK as well as for examination of the individual healing process.},
   keywords = {optical coherence tomography
pachometry
laser thermokeratoplasty
thermal damage
tissue},
   ISSN = {0941-293X},
   DOI = {DOI 10.1007/s003470050143},
   url = {<Go to ISI>://WOS:000071246700003},
   year = {1997},
   type = {Journal Article}
}

@article{Geerling1996,
   author = {Geerling, G. and Brinkmann, R. and Koop, N. and Klingemann, I. and Laqua, H. and Birngruber, R.},
   title = {Laser thermokeratoplasty - Experimental study in minipigs with a cw-IR laser diode},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {37},
   number = {3},
   pages = {304-304},
   note = {Tx397
Times Cited:0
Cited References Count:0},
   ISSN = {0146-0404},
   url = {<Go to ISI>://WOS:A1996TX39700304},
   year = {1996},
   type = {Journal Article}
}

@article{Wetzel1996,
   author = {Wetzel, W. and Brinkmann, R. and Koop, N. and Schroer, F. and Birngruber, R.},
   title = {Photofragmentation of lens nuclei using the Er:YAG laser: Preliminary report of an in vitro study},
   journal = {Ger J Ophthalmol},
   volume = {5(5)},
  
   pages = {281-284},
   note = {Vq341
Times Cited:13
Cited References Count:12},
   abstract = {The energy of the erbium:YAG laser (2,940-nm wave-length) can be used for minimally traumatic photoablation due to its high absorption at the tissue water and its consequently low penetration depth. Laser sclerostomy ab externo, an application of this principle, has undergone advanced clinical investigation. Another potential application is photofragmentation of the lens for cataract extraction. A laboratory model Er: YAG laser (flashlamp-pumped, 200-mu s pulse length, 5-Hz repetition frequency) was coupled to a short low-OH quartz fiber (400 mu m in diameter). The laser energy was applied by direct contact of the fiber tip to human lenses with very dense cataract. The lenses rested in a small cuvette filled with an aqueous-humor-analogous fluid. The fragmentablation rate was evaluated in relation to the number of pulses and the pulse energy. A laser-triggered flash-photography unit was engaged to visualize the ablation dynamics. We found tissue-ablation rates to range from 4 to 19 mu g/pulse, depending on the nucleus density and ulse energy. The maximal size of the removed fragments was always below 500 mu m During ablation, rapidly increasing and collapsing cavitation bubbles were photographed at the distal tip of the application fiber. The impact radius of these cavitation effects markedly exceeded the pure penetration depth of laser radiation at a 2.9-mu m wavelength. A clinical application of the method should be possible as judged by the results obtained for tissue-ablation rate and fragment size. Cavitation-bubble dynamics seems to be responsible for the high fragmentation efficiency. Special application probes have to be developed to optimize ablation and to prevent inadvertent destruction of the posterior lens capsule by cavitation effects.},
   keywords = {phacoemulsification
er:yag laser
cavitation effects
ablation
surgery},
   ISSN = {0941-2921},
  url = {https://www.osti.gov/etdeweb/biblio/7016223},
   year = {1996},
   type = {Journal Article}
}

@article{Gerling1996,
   author = {Gerling, G. and Vogel, A. and ElHifnawi, E. and Koop, N. and Droge, G. and Birngruber, R. and Brinkmann, R.},
   title = {Morphological and biomorphometrical observations on laser thermal keratoplasty - Histological and biomorphometrical examination of the relationship between refractive change and the volume of laser thermal keratoplasty lesions following Cr:Tm:Ho:YAG laser treatment},
   journal = {German Journal of Ophthalmology},
   volume = {5},
   number = {2},
   pages = {84-91},
   note = {Vf915
Times Cited:4
Cited References Count:21},
   abstract = {Laser thermal keratoplasty (LTK) is currently under clinical trial for the correction of hyperopia and hyperopic astigmatism by means of collagen coagulation in the peripheral cornea. The purpose of our study was to optimize the ratio between the volume of damaged corneal stroma and the refractive effect so as to minimize potential side effects such as endothelial damage or induction of glare phenomena. We therefore performed histological and morphometrical examinations of enucleated pig eyes to determine the relationship between the coagulated stromal volume and the refractive change after LTK using a pulsed Cr: Tm: Ho: YAG laser (wavelength 2.12 mu m) on enucleated pig eyes. The refractive change was documented with a Littman ophthalmometer. Morphometrical analysis was performed using polarized light microscopy of sirius red-stained specimens. This special stain separated the thermally changed stroma into a dark, nonbirefringent center and a birefringent peripheral zone. The volume of both zones was positively correlated with the refractive change induced. The volume was in turn influenced by the choice of laser parameters, From the ratio of the volume to the refractive change it was found that pulse energies above 30 mJ led to an enlargement of the coagulation volume without increasing the refractive change effectively. The use of high pulse energies did not improve the effect of LTK but only increased the risk of unwanted side effects. However, an increase in the laser repetition rate at a constant pulse number per spot led to refractive changes with a minimal coagulation volume. The highest relative refractive change was achieved with a dark central zone and a birefringent zone, each having a volume of about 50 - 80 x 10(-3) mm(3).},
   keywords = {laser thermal keratoplasty
hyperopic correction
biomorphometry
sirius red stain
polarization microscopy
organization
microscopy
collagen},
   ISSN = {0941-2921},
   url = {<Go to ISI>://WOS:A1996VF91500004},
   year = {1996},
   type = {Journal Article}
}

@article{Brinkmann1996-2,
   author = {Brinkmann, R. and Koop, N. and AsiyoVogel, M. N. and Kaftan, B. and Birngruber, R. and Engelhardt, R.},
   title = {CW-IR laser thermokeratoplasty: Refractive changes and analysis by optical coherence tomography and light microscopy},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {37(3)},
   
   pages = {305-305},
   note = {Tx397
Times Cited:0
Cited References Count:0},
   ISSN = {0146-0404},
   url = {<Go to ISI>://WOS:A1996TX39700305},
   year = { 1996},
   type = {Journal Article}
}

@article{Brinkmann1996-4,
   author = {Brinkmann, R. and Koop, N. and Kamm, K. and Geerling, G. and Kampmeier, J. and Birngruber, R.},
   title = {Laser thermokeratoplasty: an in vitro and in vivo-study by means of a Continous Wave Mid-IR laser diode.},
   journal = {Lasermedizin},
   volume = {12},
   pages = {179-186},
   year = { 1996},
   type = {Journal Article}
}

@inproceedings{Brinkmann1996-7,
   author = {Brinkmann, Ralf and Kampmeier, Juergen and Grotehusmann, Ulf and Vogel, Alfred and Koop, Norbert and Asiyo-Vogel, Mary and Birngruber, Reginald},
   title = {Corneal collagen denaturation in laser thermokeratoplasty},
   volume = {2681},
   pages = {56-63},
   note = {10.1117/12.239611},
   abstract = {In laserthermokeratoplasty (LTK) thermal denaturation and shrinkage of corneal collagen is used to correct hyperopia and astigmatism. In order to optimize dosimetry, the temperature at which maximal shrinkage of collagen fibrils occurs is of major interest. Since the exposure time in clinical LTK-treatment is limited to a few seconds, the kinetics of collagen denaturation as a rate process has to be considered, thus the time of exposure is of critical importance for threshold and shrinkage temperatures. We investigated the time-temperature correlation for corneal collagen denaturation within different time domains by turbidimetry of scattered HeNe laser probe light using a temperature controlled water bath and pulsed IR laser irradiation. In the temperature range of 60 degree(s)C to 95 degree(s)C we found an exponential relation between the denaturation time and temperature. For the typical LTK-treatment time of 2 s, a temperature of 95 degree(s)C is needed to induce thermal damage. Use of pulsed Holmium laser radiation gave significant scattering of HeNe laser probe light at calculated temperatures of around 100 degree(s)DC. Rate parameters according to the formalism of Arrhenius were fitted to these results. Force measurements showed the simultaneous onset of light scattering and collagen shrinkage.},
   url = {http://dx.doi.org/10.1117/12.239611},
   type = {Conference Proceedings},
Year ={  1996}
}

@article{Schirner1995,
   author = {Schirner, G. and Koop, N. and Elhifnawi, E. and Birngruber, R. and Brinkmann, R.},
   title = {Experiments with Pulsed and Continuous-Wave Laser Sources to Optimize Laserthermo-Keratoplasty},
   journal = {Vision Research},
   volume = {35},
   pages = {P167-P167},
   note = {Suppl. S
Rz562
Times Cited:0
Cited References Count:0},
   ISSN = {0042-6989},
   url = {<Go to ISI>://WOS:A1995RZ56200472},
   year = {1995},
   type = {Journal Article}
}

@article{Schirner1995,
   author = {Schirner, G. and Brinkmann, R. and Droge, G. and Koop, N. and Elhifnawi, E. S. and Birngruber, R.},
   title = {Experimental Studies to Optimize Laser-Thermokeratoplasty Using Pulsed and Cw-Laser-Sources},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {36},
   number = {4},
   pages = {S716-S716},
   note = {Qm915
Times Cited:3
Cited References Count:0},
   ISSN = {0146-0404},
   url = {<Go to ISI>://WOS:A1995QM91503294},
   year = {1995},
   type = {Journal Article}
}

@article{Binkmann1994,
   author = {Brinkmann, R. and Dröge, G. and Koop, N. and Wördemann, A. and Schirner, G. and Birngruber, R.},
   title = {Investigations on laser thermokeratoplasty},
   journal = {Lasers Light Ophthalmol},
   volume = {6},
   number = {4},
   pages = {259 - 270},
   year = {1994},
   type = {Journal Article}
}

@article{Koop1989,
   author = {Ulrich, H. and Wijnaendts-van-Resandt, R. W. and Koop, N. and Schickfuss, M. v and Rensch, C. and Ehrensperger, W.},
   title = {Quality of microstructures produced by laser lithography and system performance},
   journal = {Microelectronic Engineering},
   volume = {9},
   number = {1},
   pages = {69-72},
   ISSN = {0167-9317},
   url = {http://www.sciencedirect.com/science/article/pii/0167931789900154},
   year = {1989},
   type = {Journal Article}
}