gms | German Medical Science

Purpose: Present a new approach to increase the uveoscleral outflow path under nondestructive laser radiation as a basis for a new technology of glaucoma treatment.

Methods: Experiments have been performed with 20 minipig eyes exe-vivo and with 16 rabbit eyes in-vivo using an Erbium doped glass fiber laser of 1.56 microns in wavelength with pulse durations of 100–500 ms, pulse repetition rate of 1–4 Hz, laser power 0.5–1.5 W. Atomic Force Microscopy and Light Scattering measurements in have been used to study structure alterations in sclera due to non-uniform laser heating.

Results:

1.

It was established, for the first time, substantial increasing of uveoscleral outflow path under nondestructive laser radiation.

2.

We have observed for the first time laser-induced increase of porosity in sclera promoting uveoscleral outflow path.

3.

It was shown that laser settings providing substantial alterations in light scattering correlate well with laser parameters required for significant increase of water permeability. The comparison between reflected and transmitted laser signal through the sclera in the projection of pars plana (flat side) of the ciliary body has allowed establishing the main requirements responsible for efficacy and safety of the laser irradiation.

Conclusions: The substantial increase in uveoscleral outflow path under nondestructive laser radiation of 1.56 microns in wavelength, due to alteration in the porosity of sclera, has been established for the first time. The results obtained can be a fundamental for a new effective method of glaucoma treatment.