Choroidal Vascularity Index May Measure Photodynamic Therapy Treatment Response

Choroidal vascularity index may significantly decrease, serving as a measure of treatment response in eyes with chronic central serous chorioretinopathy (CSC) treated with full-dose-full-fluence photodynamic therapy (fd-ff-PDF), according to a study published in Ophthalmic and Physiological Optics.

Researchers included 23 study participants (mean age, 43.4 years; 78.3% men) with unilateral chronic CSC who were treated with fd-ff-PDT in the retrospective cohort study. The researchers compared subfoveal choroidal thickness and choroidal vascularity index of the affected eyes and fellow eyes, which were used as controls, at baseline and at 1, 3 and 6 months following fd-ff-PDT treatment.

At baseline, choroidal vascularity index was comparable between eyes treated with fd-ff-PDT and control eyes (P =.59), according to the report. However, this measurement was significantly lower by 1.63% (95%CI, 0.29%–2.9%; P =.01) at 1-month follow up, 1.88% lower at 3-month follow up (95% CI, 0.58%–3.17%; P =.002), and 1.61% lower (95% CI, 0.30%–2.9%; P =.01) at 6-month follow up compared with baseline.

In addition to lowering choroidal vascularity index, fd-ff-PDT resulted in significantly thinner subfoveal choroidal thickness, with decreases of 80.47 μm (95% CI, 47.86–113.09), 92.82 μm (95% CI, 53.82–131.82), and 93.39 μm (95% CI, 53.53–133.24) noted at months 1, 3, and 6, respectively following the treatment (P <.001 for all). No significant differences were observed among eyes that served as controls.

Best corrected visual acuity improved following fd-ff-PDT (P <.001), with improvements of 0.17 logarithm of the minimum angle of resolution (logMAR; 95% CI, 0.06–0.28), 0.20 logMAR (95% CI, 0.10–0.29) and 0.23 logMAR (95% CI, 0.11–0.35) noted at the 1, 3, and 6 month follow-up visits, respectively.

“The baseline comparable [choroidal vascularity index] values in the affected and fellow eyes of chronic CSC patients argue for its utility as an activity criterion,” according to the study authors. “These findings support the role of [choroidal vascularity index] as a measurement of treatment response in fd-ff-PDT-treated chronic CSC patients.”

Study limitations include a small sample size, short follow-up period, single center design, retrospective nature, the use of single-line scanning for obtaining choroidal thickness measurements, and performing choroidal vascularity index measurements only in the subfoveal 1500 μm choroid.