Retinal damage thresholds from 100-millisecond laser radiation exposure at 1319 nm: a comparative study for rabbits with different ocular axial lengths.

With the widespread use of high-power laser systems in the wavelength spectrum between 1300 and 1400 nm, the risk of ocular damage becomes more serious and concerning. Existing ocular bio-effects studies have revealed unique damage characteristics, the damage mechanisms involved, and the trends of damage thresholds in this wavelength range. However, the influence of ocular axial length on retinal damage thresholds has not been investigated quantitatively. In this paper, using a 1319 nm continuous-wave laser, the in-vivo retinal damage thresholds were determined for two groups of chinchilla grey rabbits with the ocular axial lengths of 15.97 and 17.25 mm, respectively. The incident corneal irradiance diameter was fixed at 5 mm and the exposure duration was 0.1 s. The determined ED50 values at 24-h post-exposure for the axial lengths of 15.97 and 17.25 mm were 1.06 and 1.79 J, respectively. Detailed analysis revealed that a sufficient margin existed between the damage threshold and MPE for adult humans, but for the newborn eyes, the safety factor may be less than 2.3.