Purpose:
To demonstrate the utility of the large spot size (LSS) setting using the binocular laser indirect ophthalmoscope (LIO) delivery system for peripheral ablation in children.
Methods:
The medical records of pediatric patients who received LIO peripheral photocoagulation from January 1 2007 to October 1 2011 were reviewed. Seven eyes of four patients received LSS diode photocoagulation therapy and seven eyes of four patients received standard spot diode photocoagulation therapy for a variety of diseases including Coats disease, vasculitis with peripheral neovascularization, pars planitis, and prethreshold retinopathy of prematurity (ROP). One patient with bilateral prethreshold ROP received therapy with standard spot size burns placed adjacently to LSS burns. Using an NIH sponsored image analysis program called Image J, the area of retinal spots was determined in units of pixels.
Results:
For the patient with prethreshold ROP who received adjacent treatment, the area range for standard spots using Image J analysis was 805-1294 pixels and for LSS was 1699-2311 pixels. Using theoretical retinal areas, fluence for the standard spot setting was calculated to be 462 mJ/mm² while LSS has a reduced fluence of 104 mJ/mm², producing more uniform spots. Additionally, LSS LIO halved the number of spots required for treatment of bilateral prethreshold ROP eyes.
Conclusions:
In pediatric patients requiring peripheral photocoagulation, we report reduced number of spots required to deliver treatment as well as the ability to deliver spots with increased uniformity and reduced fluence using the LSS LIO technique. Given the reduction in spots required, LSS LIO can reduce treatment times without a reduction in efficacy.
Clinical Trial:
Mayo Clinic IRB, 11-006584
Keywords: laser • retinopathy of prematurity • retina