3.3. Medical intervention

We performed laser therapy in the following situations: stage 3 zone 1 ROP, stage 3 zone 2 ROP, stage 2 zone 1 ROP and AP-ROP. Infants with AP-ROP were treated within 24 h from diagnosis and the rest of them within 48 h from diagnosis.

All laser therapies were carried out under sedation in the Neonatology Unit. We used a portable indirect diode laser, with an emission of 810 nm, and laser energy was delivered transpupillary (Figure 1).

A mixture of tropicamide 0.5% and phenylephrine 2.5% was instilled preoperatively, in order to dilate the pupils. In order to gain access to the retina, a lid speculum, a sclera indentor and a + 28 diopter lens were used (Figure 2).

Indirect diode laser photocoagulation was performed with the following parameters: 200 microns laser spot, 200 ms duration and 150–300 mW power, according to the retinal reaction. The obtaining of a whitish retinal spot was aimed. Laser spots were applied in a confluent manner, with no space between impacts, to cover all the surface of the non-vascular retina, up to ora serrata. The number of impacts varied between 1500 and 4000/eye.

The first postlaser review took place 7 days after treatment. In case of regression, examinations continued every 5–6 days, until there was clear evidence of ROP regression. In case of regression failure, laser was completed immediately. The treated eyes were monitored with a frequency dictated by the clinical course of the disease, in order to address any risk of sequel.
