Abstract
Purpose :
To evaluate the changes in the choroidal blood flow and morphology after panretinal photocoagulation (PRP) in eyes with severe nonproliferative diabetic retinopathy (S-NPDR).
Methods :
This was a prospective, comparative study of 39 eyes from 39 patients with type 2 diabetes and S-NPDR with no macula edema that underwent PRP by conventional laser (17 eyes) or pattern scan laser (PASCAL;22 eyes). The choroidal blood flow was assessed by laser speckle flowgraphy. Spectral-domain optical coherence tomography (SD-OCT) was used to obtain images of the choroid in the macular region that were used to measure the subfoveal choroidal thickness (SFCT), and to calculate the luminal and stromal areas by the binarization method before and 1,4,8 and 12 weeks after the two types of PRP treatments.
Results :
The mean number of the photocoagulation burns was 1524 ± 157 in the conventional laser group and 4959 ± 582 in the PASCAL group. In the conventional laser group, the macular choroidal mean blur rate (MBR) was significantly reduced after 4,8 and 12 weeks (Week 4, 87.8％, P=0.028; Week 8, 87.2％, P=0.026; Week 12, 86.4％, P=0.021). In the PASCAL group, the macular choroidal mean blur rate (MBR) was significantly reduced only at Week 12 (85.7％, P=0.001). The SFCT, luminal,and stromal areas of the choroid were increased at 1 week following PRP but were decreased at Week 8 (P=0.001, P<0.001,rescpectively) in both groups. The changes in the choroidal MBR with time did not correspond with that of any of the choroidal morphological changes as determined by SD-OCT. The differences in the ratio of the MBR and the SFCT was not significant between the conventional laser and PASCAL groups at any time after PRP.
Conclusions :
The results suggest that appropriate PRP treatment even by the PASCAL method will reduce the choroidal blood flow and the choroidal morphological components. The changes in the choroidal MBR are not associated with the changes in the choroidal morphology in the early post-treatment period.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.