Spatially resolved transmission of highly focused beams through the cornea and sclera between 1400 and 1800 nm

Abstract

We investigated the spatial confinement oflaser beams focused through human cornea and sciera using long near infrared wavelengths. Using a 0.4 numerical aperture lens, we measured the spatial transmission ofthe smallest emergent beam on the back surface ofthe tissue. We found that standard axia' transmission measurements over estimate the amount of unscattered light for the sciera and that 1600 run to 1700 nm had the maximum unscattered transmission through cornea and sciera. The light confinement may be useful in producing localized subsurface linear and nonlinear optical processes.

NIR laser tissue welding of in vitro porcine cornea and sclera tissue

“…This was mostly likely due to poor apposition of the tissues before welding and possibly to different hydration levels of the tissues. This also may have been a direct result of insufficient power delivered to the tissue, the rate of energy delivery or possibly lakes of H 2 O that may have formed in the tissues after the death of the animals [51]. These issues will be addressed by comparing different combinations of light delivery, i.e., different cross section patterns, scan rates, power levels, and spot sizes, see Figure 2 and Table 1.…”

Optical Biomedical Diagnostics

“…Даже такая прозрачная ткань, как роговица глаза человека, рассеивает свет, поэтому полное и аксиальное (коллимированное) пропускания не являются идентичными [59]. Благодаря слабому рассеянию пики поглощения воды хорошо видны на 300, 980, 1180, 1450, 1900 и 2940 нм, они обеспечивают малое пропускание через роговицу в УФ и ИК спектральных областях.…”

<title>Immersion effects in tissues</title>

“…Sometimes, the scatterer concentration increase is likely more dominant than the reduction in index mis-match.5 '28 It is possible to achieve a marked impairment of scattering by matching the refractive indices of scattering centers and ground matter by means of intra-tissue administration of appropriate chemical agents. 1-3, 7-9, 13, [16][17][18] The transmission of collimated light by a tissue layer ofthickness d with the matched boundaries is defined as TJ/J0(_p.d) (9) where jo and I are the intensities of the incident and detected light, respectively; p = Pa + / is the extinction coefficient, ha and -' are the absorption and scattering coefficients, respectively.…”