Comparison of retinochoroidal vascular and structural changes after half-dose photodynamic therapy versus half-fluence photodynamic therapy based on optical coherence tomography angiography in eyes with chronic central serous chorioretinopathy.

Abstract

To compare the efficacy of half-fluence photodynamic therapy (PDT) and half-dose PDT on the choroidal structure via perfusion of the retinal plexus and choriocapillaris in eyes with chronic central serous chorioretinopathy (cCSCR). This retrospective study included 43 eyes in 43 patients with cCSCR. Patients in group 1 received half-fluence (verteporfin 6 mg m-2) PDT and those in group 2 received half-dose (verteporfin 3 mg m-2) PDT. Enhanced depth imaging optical coherence tomography (EDI-OCT) and optical coherence tomography angiography (OCTA) images were recorded 1 day before and 3 months after PDT. Total choroidal area (TCA), luminal area (LA), and stromal area (SA) were calculated using Image J software. From baseline to 3 months post PDT TCA decreased from 2.43 ± 0.47 mm2 to 2.08 ± 0.59 mm2 (P < 0.001), LA decreased from 1.78 ± 0.11 mm2 to 1.54 ± 0.26 mm2 (P < 0.001), and SA decreased from 0.76 ± 0.33 mm2 to 0.53 ± 0.37 mm2 (P < 0.001) in group 1. Choriocapillaris vascular density measured via OCTA increased from 37.82 ± 10.99 at the initial visit to 44.96 ± 15.34 at month 3 after half-fluence PDT administered to the fovea (P < 0.001). Deep capillary plexus vessel density was 32.49 ± 11.36 at baseline and increased to 43.27 ± 11.40 at month 3 after half-fluence PDT administered to the fovea (P < 0.001) in group 1. TCA decreased to 2.00 mm2 ± 0.51 mm2 from 2.39 mm2 ± 0.43 mm2 (P < 0.001), LA decreased to 1.53 ± 0.29 mm2 from 1.74 ± 0.16 mm2 (P = 0.019). Although SA decreased from 0.76 ± 0.33 mm2 to 0.53 ± 0.37 mm2 in group 2, the difference was not significant (P = 0.07). Based on OCTA, choriocapillaris vascular density increased from 43.68 ± 10.38 mm2 at baseline to 47.46 ± 6.42 mm2 at 3 months after half-dose PDT onto the fovea (P = 0.049). Deep capillary plexus vessel density increased from 34.37 ± 9.36 mm2 at the initial visit to 38.17 ± 8.81 mm2 3 months after half-dose PDT onto the fovea (P = 0.046) in group 2. At 3 months post PDT subretinal fluid (SRF) was significantly higher resolution in group 1 than in group 2 (P = 0.021). OCTA shows there is a significant increase in deep capillary plexus and choriocapillaris perfusion 3 months after both half-fluence PDT and half-dose PDT. Although there was a significant decrease in LA in both groups, based on OCTA there was a significant decrease in SA, a significant increase in choriocapillaris and deep capillary perfusion in group 1; therefore, the level of SRF resolution at month 3 post PDT might explain its higher incidence in group 1.