Abstract
Corneal epithelial damage thresholds for exposures to sequences of pulses of 1.54 μm infrared radiation produced by an Er fiber laser were investigated. Thresholds were determined for sequences of 8 to 128 pulses at a repetition frequency of 10 Hz and 8 to 256 pulses at 20 Hz. The duration of the individual pulses was 0.025 sec and the 1/e diameter of the laser beam was 0.1 cm. The results show that threshold damage is correlated by an empirical power law of the form H th = CN β, where H th is the threshold radiant exposure per pulse, and N is the number of pulses. The constant C is different for the 10 Hz and 20 Hz exposures and, for both cases, is greater than the estimated threshold for a single 0.025 sec pulse. Thus the empirical power law breaks down for small numbers of pulses (viz., N< 8), where it overestimates the damage thresholds. Temperature calculations for the threshold exposure conditions show that a critical temperature model also correlates the multiple-pulse injury thresholds.
Original language | English (US) |
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Article number | 68 |
Pages (from-to) | 423-428 |
Number of pages | 6 |
Journal | Progress in Biomedical Optics and Imaging - Proceedings of SPIE |
Volume | 5688 |
DOIs | |
State | Published - Jul 21 2005 |
Event | Ophtalmic Technologies XV - San Jose, CA, United States Duration: Jan 22 2005 → Jan 25 2005 |
Keywords
- Cornea
- Damage model
- Infrared
- Laser safety
- Rabbit
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Biomaterials
- Atomic and Molecular Physics, and Optics
- Radiology Nuclear Medicine and imaging