Verteporfin Photodynamic Therapy Dose Effects Blood Flow in Serous Chorioretinopathy

Among patients with chronic serous chorioretinopathy (CSC) who are treated with a reduced dose of verteporfin photodynamic therapy (PDT), a study shows a significant reduction in subfoveal choroidal circulation, according to results published in BMC Ophthalmology. 

Although CSC is among the most common retinal diseases, the pathophysiology is still unclear. PDT with verteporfin has been an effective therapy for CSC but complications such as retinal pigment epithelium atrophy or tearing, secondary choroidal neovascularization, and choriocapillaris ischemia can occur. To reduce these complications, several studies have assessed outcomes of efficacy when reducing the dose of PDT. 

As the effects of several reduced doses of PDT are still not well understood, a team of investigators in Japan conducted a retrospective study (UMIN Identifier: 000026850) to characterize modifications in choroidal blood flow and thickness, as measured by laser speckle flowgraphy (LSFG), in patients with chronic CSC who were treated with either one-half or one-third the dose of PDT. LSFG was used to measure the best-corrected visual acuity, central retinal thickness, central choroidal thickness, and mean blur rate in the macula and optic nerve head at pretreatment, as well as 2 weeks, 1 month, 3 months, and 6 months post-treatment. 

A total of 27 eyes from 27 patients with serous retinal detachment due to chronic CSC for more than 6 months were included in the analysis; 15 eyes were treated with one-third PDT and 12 eyes were treated with one-half PDT. The only significant demographic at baseline between the cohorts was age (P =.04). 

There was a significant elevation in the preoperative central retinal thickness in both the one-half PDT (P =.0002) and one-third PDT (P =.0013) groups. After 1 month of treatment, there was 92% and 93% disappearance rate of serous retinal fluid in the one-half and one-third PDT cohorts, respectively. 

A recurrence of serous retinal detachment was observed in an eye in the one-half PDT group at 6 months follow-up and in 2 eyes in the one-third PDT group at 3 months follow-up. Compared with baseline, there were no significant improvements in best-corrected visual acuity at any of the follow-up time points in either treatment arm. 

The average mean blur rate in the macular area significantly decreased at every follow-up point for patients treated with one-half dose of PDT; however, such significant decreases were only observed at the 2 week follow-up in the one-third PDT group.

The rate of change in central choroidal thickness was significant at all follow-up points for the one-half PDT arm, and significant at 2 weeks, 1 month, and 3 months follow-up, but not 6 months, for the one-third PDT arm.

Although there were no significant association between treatment arm and mean blur rate in the optic nerve head for any of the follow-up points compared with baseline, the investigators noted a significant correlation between mean blur rate in the macular area and central choroidal thickness (Spearman’s rank correlation test, r =0.27; P =.0039).

“Hyperpermeability of choroidal blood vessels and the consequent increase in choroidal hydrostatic pressure are considered to be the key pathogenic factors for CSC,” according to researchers. “The association between choroidal blood flow and localised hyperpermeability of the choroid in the subretinal space may be an indicator of disease activity and requires further investigation.” 

Reference 

Kumashiro S, Takagi S, Itokawa T, Tajima A, Kobayashi T, Hori Y. Decrease in choroidal blood flow after half and one-third dose verteporfin photodynamic therapy for chronic central serous chorioretinopathy. BMC Ophthalmol. 2021;21(1):241. doi:10.1186/s12886-021-01980-w