Pattern Scan Laser refers to a laser delivery system where multiple laser spots of short pulse duration are delivered in a preset pattern. These pattern scan laser systems were developed to decrease the treatment times for diabetic retinopathy, especially pan-retinal photocoagulation. In order to use the scanner, it was necessary to reduce the pulse-duration of the laser by decreasing the duration of the laser to 10-20 milliseconds instead of the standard 100 to 200 milliseconds.
Though the initial interest in these systems was in decreasing the treatment time by decreasing the duration of burns, subsequently it was found that there were a lot of unanticipated benefits achieved by decreasing the duration of laser application.
Patients treated with pattern scan laser have significantly less pain as compared to conventional laser and apart from pain all the side effects/ complications of conventional lasers were significantly less in pattern laser.
With pattern scan laser, there is significantly less damage to visual fields, much lower incidence of macular edema (swelling in the most sensitive center of the retina), loss of contrast sensitivity and loss of dark adaptation. More so, in selective cases, full pan-retinal photocoagulation can be done in one session instead of 3-4 sessions usually done with a conventional laser.
Figure 1. Image of a conventional laser with extensive scarring.
Figure 2. Image of Pattern Scan Laser with full PRP in one session