Retinal thermal damage threshold dependence on exposure duration for the transitional near-infrared laser radiation at 1319 nm

Abstract

The retinal damage effects induced by transitional near-infrared (NIR) lasers have been investigated for years. However, the damage threshold dependence on exposure duration has not been revealed. In this paper, the in-vivo retinal damage ED50 thresholds were determined in chinchilla grey rabbits for 1319 nm laser radiation for exposure durations from 0.1 s to 10 s. The incident corneal irradiance diameter was fixed at 5 mm. The ED50 thresholds given in terms of the total intraocular energy (TIE) for exposure durations of 0.1, 1 and 10 s were 1.36, 6.33 and 28.6 J respectively. The ED50 thresholds were correlated by a power law equation, ED50 = 6.31t0.66 [J] where t is time [s], with correlation coefficient R = 0.9999. There exists a sufficient safety margin (factor of 28~60) between the human ED50 thresholds derived from the rabbit and the maximum permissible exposure (MPE) values in the current laser safety standards.

Comparative study of retinal injuries induced by a 420-750 nm supercontinuum source and a 532 nm laser

“…For the exposure duration of 0.1 s, the ED 50 damage threshold was about 68.1 mW. This value was significantly higher than the values for lasers in visible wavelengths (11.2-24.7 mW) [17], but obviously lower than the values for infrared wavelengths such as 1064 nm and 1319 nm (145 mW and 13.6 W respectively) [21,22], indicating that the retinal injury induced by the SC source was a combined effect of visible light and near infrared (IRA) radiation. As we know, the retinal minimum spot size for visible radiation is in the range of 7-30 μm, and enlarges to 30-110 μm in the near-infrared wavelength range due to dispersion effect [17].…”

Ocular damage effects from 1338-nm pulsed laser radiation in a rabbit eye model

“…This study determined corneal damage thresholds for 1338 nm laser with spot sizes from 0.28 mm to 3.55 mm at fixed exposure duration. In a recent report, the retinal damage thresholds were determined in chinchilla grey rabbits for 1319 nm laser radiation for exposure durations from 0.1 s to 10 s [9]. The damage thresholds for exposure durations of 0.35 ms, 0.65 ms, and 80 ms were also determined in a rhesus model [2,3,6].…”

“…Due to the widespread use of laser systems in this region and the rapid increase of laser power/energy, the risk of ocular damage becomes more serious and thus receives more concern [3]. In the past two decades, ocular damage threshold studies have been conducted at diverse laser radiation parameters to quantify the ocular hazards [1][2][3][4][5][6][7][8][9][10][11][12][13]. International safety committees, such as the International Commission of Non-Ionizing Radiation Protection (ICNIRP) and the American National Standards Institute (ANSI), analyze these damage threshold studies and make recommendations for the Maximum Permissible Exposures (MPEs) [14,15].…”

Porcine skin damage thresholds and histological damage characteristics from 1319-nm laser radiation

“…17 Third, a retinal or corneal lesion involves the full thickness of that layer, even at the threshold level. [18][19][20][21] Fourth, the corneal or retinal damage thresholds can be correlated by power law functions, having similar trends with other visible or far-IR lasers. 20,21 Fifth, the ocular axial length is a great influential factor on the retinal damage threshold, whereas retinal pigmentation is a relatively minor factor.…”

“…[18][19][20][21] Fourth, the corneal or retinal damage thresholds can be correlated by power law functions, having similar trends with other visible or far-IR lasers. 20,21 Fifth, the ocular axial length is a great influential factor on the retinal damage threshold, whereas retinal pigmentation is a relatively minor factor. However, for lasers emitting visible radiation, the retinal damage threshold is significantly relevant to the retinal pigmentation, and the ocular axial length is a secondary influential factor.…”