Abstract
Purpose: :
In patients with diabetic retinopathy, panretinal photocoagulation (PRP) is performed to treat retinal ischemia. PRP, however, causes a reduction of blood flow, which is an undesirable side effect. A pattern scan laser (PSL) uses a shorter pulse duration of spots which reduces collateral damage and thus the adverse effects of PRP. This study compares retinal blood flow and visual function in severe diabetic retinopathy following PRP using either a PSL or a conventional laser (CVL).
Methods: :
Ten patients with diabetic retinopathy in both eyes underwent PRP using a PSL (2 sessions/ ≈3000 spots) in one eye, and PRP using a CVL (3 sessions/ ≈2000 spots) in the other eye. Retinal blood flow was assessed with mean blur rate (MBR) measured by laser speckle flowgraphy of the optic disc once a month for 6 months. Central macular thickness (CMT) measured by optical coherence tomography and best-corrected visual acuity (VA) using a logMAR chart was also evaluated.
Results: :
MBR was decreased during PRP in both the eyes treated with a PSL (73.2±6.9%) and the eyes treated with a CVL (71.5±8.0%). There was no significant difference between the two groups. After completion of PRP, the MBR in the eyes treated with a PSL improved and was 89.4±8.3% at 6 months. The MBR in the eyes treated with a CVL was unchanged (70.3±9.6% at 6 months: p<0.01). Both CMT and VA in the eyes treated with a PSL were unchanged during the clinical course, while those parameters in the eyes treated with a CVL worsened over time.
Conclusions: :
Compared to a CVL, PRP with a PSL resulted in rapid recovery of blood retinal flow after the completion of PRP, and had less influence on macular function in patients with severe diabetic retinopathy.
Keywords: diabetic retinopathy • laser • imaging/image analysis: clinical