Evaluation of thermal load during laser corneal refractive surgery using infrared thermography

Brunsmann, U.; Sauer, Udo; Arba-Mosquera, Samuel; Magnago, Thomas; Triefenbach, Nico

doi:10.1016/j.infrared.2010.06.003

Cited by 24 publications

(16 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has also been found that, IRT is useful in studying follow-up effects of methylprednisolone pulse therapy. Brunsmann et al used IRT to evaluate thermal load during laser corneal refractive surgery [191]. Ng et al proposed that, enhanced eye temperature could be a possible indication of fever [192].…”

Section: Diagnosis Of Rheumatic Diseasesmentioning

confidence: 99%

Medical applications of infrared thermography: A review

Lahiri

Bagavathiappan

Jayakumar

et al. 2012

Infrared Physics & Technology

984

610

View full text Add to dashboard Cite

The primary objective of this study is the development of transparent thin film materials in the IR enabling strong infrared absorption of organic compounds in the vicinity of metal nanoparticles by the surface plasmon effect. For developing these optical micro-sensors, heterostructures combining gold nanoparticles and chalcogenide planar waveguides are fabricated and adequately characterized. Single As 2 S 3 and Ge 25 Sb 10 Se 65 amorphous chalcogenide thin films are prepared by radiofrequency magnetron sputtering. For the fabrication of gold nanoparticles on a chalcogenide planar waveguide, direct current sputtering is employed. Fabricated single layers or hetero-structures are characterized using various techniques to investigate the influence of deposition parameters. The nanoparticles of gold are functionalized by a self-assembled monolayer of 4-nitrothiophenol. Finally, the surface enhanced infrared absorption spectra of 4-nitrothiophenol self-assembled on fabricated Au/Ge-Sb-Se thin films hetero-structures are measured and analyzed. This optical component presents a ~24 enhancement factor for the detection of NO 2 symmetric stretching vibration band of 4-nitrothiophenol at 1336 cm −1 .

show abstract

Section: Diagnosis Of Rheumatic Diseasesmentioning

confidence: 99%

Medical applications of infrared thermography: A review

Lahiri

Bagavathiappan

Jayakumar

et al. 2012

Infrared Physics & Technology

984

610

View full text Add to dashboard Cite

show abstract

“…Using the camera software, the measurements were internally adjusted for the recording distance, and emissivity was set at 0.9 in agreement to the literature. 20 With our test setup, we can expect a measurement error of AE0.5°C due to the thermal camera. 20 The pixel with the highest recorded temperature within the region of interest was analyzed.…”

Section: Methodsmentioning

confidence: 96%

“…Commercially available thermography imaging systems featuring much greater system time constants, have been used for the evaluation of mean and maximum temperature rise within an ablated area. 20 Kim et al 21 studied the expression patterns of heat shock proteins following eyeball heating or cooling in relation to corneal wound healing and intraocular complications after excimer laser treatment. They were able to demonstrate that heat shock proteins were induced by thermal preconditioning and appeared to be a major factor in corneal protection against serious thermal damage.…”

Section: Introductionmentioning

confidence: 99%

“…If this thermal load is not controlled, it may lead to denaturation of the collagen proteins inducing thermal damage. 11,30,31 Minimizing the thermal load of ablation in high-speed laser corneal refractive surgery has been analyzed theoretically and clinically in the past, in PMMA, porcine as well as human cornea, generating several models 11,20,[32][33][34] for temperature increase during laser ablation. However, the real impact of the thermal load in laser corneal refractive surgery is still controversially discussed and warrants further in-depth exploration, particularly for high-repetition-rate scanning-spot excimer laser applications.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of the change in peak corneal temperature during excimer laser ablation in porcine eyes

Arba-Mosquera

Verma

2015

J. Biomed. Opt.

View full text Add to dashboard Cite

The objective is to characterize the impact of different ablation parameters on the thermal load during corneal refractive surgery by means of excimer laser ablation on porcine eyes. One hundred eleven ablations were performed in 105 porcine eyes. Each ablation was recorded using infrared thermography and analyzed mainly based on the two tested local frequencies (40 Hz, clinical local frequency; 1000 Hz, no local frequency). The change in peak corneal temperature was analyzed with respect to varying ablation parameters [local frequency, system repetition rate, pulse energy, optical zone (OZ) size, and refractive correction]. Transepithelial ablations were also compared to intrastromal ablations. The average of the baseline temperature across all eyes was 20.5°C±1.1 (17.7°C to 22.2°C). Average of the change in peak corneal temperature for all clinical local frequency ablations was 5.8°C±0.8 (p=3.3E-53 to baseline), whereas the average was 9.0°C±1.5 for all no local frequency ablations (p=1.8E-35 to baseline, 1.6E-16 to clinical local frequency ablations). A logarithmic relationship was observed between the changes in peak corneal temperature with increasing local frequency. For clinical local frequency, change in peak corneal temperature was comparatively flat (r 2 =0.68 with a range of 1.5°C) with increasing system repetition rate and increased linearly with increasing OZ size (r 2 =0.95 with a range of 2.4°C). Local frequency controls help maintain safe corneal temperature increase during excimer laser ablations. Transepithelial ablations induce higher thermal load compared to intrastromal ablations, indicating a need for stronger thermal controls in transepithelial refractive procedures.

show abstract

“…21 Other studies have shown this thermal response to be magnified with increasingly desirable pulse rates and laser fluences. 22 Some newer lasers running in excess of 1000 Hz and 500 mJ/cm 2 are capable of reaching maximum temperature increases of almost 20°C. 36 Thermal energy denatures the triple-helix structure of the corneal collagen, creating a contractile force along its lengthwise dimension.…”

mentioning

confidence: 99%

Corneal Surface Asphericity, Roughness, and Transverse Contraction after Uniform Scanning Excimer Laser Ablation

McCafferty

Schwiegerling

Enikov

2012

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

PURPOSE.To examine the interaction between the excimer laser and residual tissue. METHODS. Ten cadaveric porcine eyes with exposed corneal stroma and plastic test spheres underwent uniform 6-mm ablation with a scanning excimer laser. Corneal profilometry of the central 3 mm was measured with submicrometer resolution optical interferometry, before and after uniform excimer ablation. Eleven surface-marked eyes were photomicrographed before and after excimer ablation. Images were superimposed, and mark positional changes were measured. RESULTS. Uniform scanning excimer laser ablation of the corneal stroma produces a significant central steepening and peripheral flattening in the central 3-mm of the diameter. The central 1-mm corneal curvature radius (r) decreased from r ϭ 10.07 Ϯ 0.44 (95% CI) to 7.22 Ϯ 0.30 mm, and the central 2-mm radius decreased from r ϭ 10.16 Ϯ 0.44 to 8.10 Ϯ 0.43 mm. Q values, measuring asphericity in the 2-mm radius of the central cornea, were significantly lower before than after ablation (Ϫ5.03 Ϯ 4.01 vs. Ϫ52.4 Ϯ 18.7). Surface roughness increased significantly from 0.65 Ϯ 0.06 to 1.75 Ϯ 0.32 m after ablation. The central 2 mm of the stromal surface contracted by 2.21% Ϯ 0.80% at a sustained temperature of 5°C. Ablation of plastic spheres produced no significant change. CONCLUSIONS. The excimer laser interacts with the nonablated residual stromal surface in a characteristic fashion not seen with isotropic, inorganic material. Increases in asphericity, surface roughness, surface contraction, and stromal morphologic changes are supportive of this interaction. The surface changes demonstrated may be indicative of temperature-induced transverse collagen fibril contraction and stress redistribution, or the ablation threshold of the stromal surface may be altered. This phenomenon may be of increased importance using lasers with increased thermal load. (Invest Ophthalmol Vis Sci.

show abstract

Evaluation of thermal load during laser corneal refractive surgery using infrared thermography

Cited by 24 publications

References 18 publications

Medical applications of infrared thermography: A review

Medical applications of infrared thermography: A review

Analysis of the change in peak corneal temperature during excimer laser ablation in porcine eyes

Corneal Surface Asphericity, Roughness, and Transverse Contraction after Uniform Scanning Excimer Laser Ablation

Contact Info

Product

Resources

About