1. Introduction

Retinopathy of prematurity (ROP) can be a major cause of pediatric blindness worldwide if not diagnosed and treated promptly [1]. Visual loss in ROP is due to the complications related to retinal ischemia: retinal neovascularization, vitreous hemorrhage and finally total retinal detachment. Fortunately, ROP is a largely preventable cause of visual impairment in children. Despite the fact that in recent years, intravitreal anti-VEGF agents proved their efficacy and safety in the

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

management of ROP, the golden standard of treatment in ROP remains the laser photocoagulation of the non-vascularized retina [1].

"Plus" disease includes retinal vessel dilation and tortuosity, retinal hemorrhages and pupil

Indirect Diode Laser in the Treatment of Retinopathy of Prematurity

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Separately from the features of the "classic" ROP described above, aggressive posterior ROP (AP-ROP) has been described with the following aspects: very severe "plus" disease, posterior location (most commonly zone 1, but also posterior zone 2), ill-defined or no ridge, rapid

Also, there are two important terms that have to be defined: threshold and pre-threshold ROP. Threshold ROP includes: stage 3, zone 1 or 2, with "plus" disease, with a ridge extending on more than five contiguous or eight cumulative clock hours. Pre-threshold ROP includes the following situations: less than threshold ROP in zone 1/stage 2, zone 2 with "plus"/stage 3,

Understanding laser technology starts from the translation of the word LASER: light amplifi-

Atoms occupy various energetic levels. Lower energetic levels are associated with higher stability. If the atom absorbs energy under the shape of a photon, it "jumps" on a higher energetic level in a state of excitation. The excited atom can "fall" back spontaneously on the lower energetic level by emitting a photon. The excited atom can be "forced" to fall from the higher on the lower energetic level if it meets a photon carrying the energy equal to the difference between the two levels. This process is called stimulated emission: a photon stimu-

If we would be able to bring the majority of atoms on the superior energetic level, the incident radiation will induce the emission of a more intense beam than the incident one. This is called radiation amplifying. The key problem is to obtain a state with more atoms on the superior energetic level, which is called population inversion and is reached by pumping. In order to amplify the light, the system is closed between two parallel mirrors forming a cavity. The mirrors allow photons to jump back and forth by continuously reflecting between them, thus producing stimulated emissions. When the radiation flux becomes extremely intense, it is

1. Because the photons are emitted through energies that are liberated between two well-

2. Because the two mirrors are parallel, the laser beam is composed of highly parallel rays:

3. The emitted and the "disruptive" radiations are always in the same phase; therefore, the

These properties offer theoretical advantages to the laser radiation over the white light that are

The abovementioned principles explain the key properties of the laser radiation:

zone 2, without "plus"/stage 3 with "plus," less extended than threshold ROP [3, 4].

rigidity [3, 4].

2.3. Laser effect

progression to stage 5 ROP [3, 4].

cation by the stimulated emission of radiation.

lates the emission of another photon [5].

allowed to get out of the cavity as laser beam [5].

limited divergence.

laser radiation is coherent.

defined energetic levels, the radiation is monochromatic.

translated by its clinical applications in various ocular diseases [5].
