Abstract
Purpose: :
To compare the morphologic changes of laser lesions in the human retina in vivo performed by 2 different retinal laser systems.
Methods: :
In this prospective interventional study, 20 patients in need of panretinal photocoagulation were randomized into two groups: one group was treated with a conventional laser system (Novus Omni(c), Coherent) and the other group with a semi automated patterned scanning laser system (PASCAL(R), Optimedica). Laser lesions were imaged at day 1, week 1, and thereafter in monthly intervals up to six months using a spectral domain OCT (SD OCT) device (Spectralis(R), Heidelberg Engineering), infrared (IR) and color photo (CF) imaging.
Results: :
Laser lesions from both systems were well visible in OCT already at day 1 as focal sharply delineated tissue destruction from the outer plexiform to the photo receptor layer. At week 1, laser lesions by the Pascal laser system showed a symmetric pattern with a roundish spot shape, equal spot size and spot distance clearly detectable in IR, CF and SD OCT images. Laser lesions performed with the conventional system were shaped round to oval and in some cases confluent. Apart from that, there were no differences in the intra-retinal changes with time between both groups.
Conclusions: :
Intra-retinal lesions following photocoagulation treatment with a semiautomated laser system show high uniformity in size, shape and progression. A conventional single spot laser treatment causes the same intra-retinal lesions, however, showing a high diversity in the individual spot size and shape.
Clinical Trial: :
www.clinicaltrials.gov NCT00682240
Keywords: laser • diabetic retinopathy • imaging/image analysis: clinical