To evaluate the effect of low-fluence photodynamic therapy (PDT) on central retinal sensitivity and fixation stability as compared with standard-fluence PDT for treating chronic central serous chorioretinopathy (CSC).

Prospective longitudinal follow-up of patients enrolled in a nonrandomized clinical trial of standard-fluence vs low-fluence PDT in chronic CSC.

Forty-two eyes (42 patients) with chronic CSC were enrolled; 19 eyes received indocyanine green angiography–guided standard-fluence PDT (50 J/cm²) and 23 received indocyanine green angiography–guided low-fluence PDT (25 J/cm²). Retinal sensitivity in the central 12 degrees and fixation stability were evaluated by MP-1 microperimeter at baseline and at 3 and 12 months after PDT.

Mean central retinal sensitivity improved significantly at all time points (at 12 months vs baseline P < .01, Tukey-Kramer test), in the standard- fluence group from 11.9 to 14.4 at 12 months, and in the low-fluence-group from 11.8 to 16.3, with a significant difference between the 2 groups (P = .04, t test). Fixation stability did not change in either group (not significant, analysis of variance). At 12 months' follow-up the retinal sensitivity significantly correlated with best-corrected visual acuity in both groups (standard-fluence, r = −0.52, P = .02; low-fluence, r = −0.54, P = .01).

The study shows a significant improvement in macular sensitivity after PDT in eyes with chronic CSC, with greater efficacy in low-fluence-treated eyes. Microperimetry data suggest that low-fluence PDT may be a good treatment option in patients with chronic CSC.