This prospective study found that low-fluence photodynamic therapy (PDT) yielded superior one-year outcomes to intravitreal ranibizumab in the treatment of chronic central serous chorioretinopathy (CSC).
The study included 32 patients (34 eyes) with recurrent CSC or chronic CSC with symptoms of more than six months' duration. They were randomized to a single session of low-fluence PDT or three consecutive monthly injections of ranibizumab. Rescue treatment—low-fluence PDT for the ranibizumab group and intravitreal ranibizumab for the low-fluence PDT group—was given after three months if subretinal fluid persisted or recurred after primary treatment.
At one year, 16 eyes (88.9 percent) in the PDT group maintained complete resolution of subretinal fluid without rescue treatment compared with two eyes (12.5 percent) in the ranibizumab group. Two eyes in the PDT group and 11 eyes in the ranibizumab group met the criteria for rescue treatment.
In the low-fluence PDT group, the mean decrease in central retinal thickness was significantly greater than in the ranibizumab group until month six (P < 0.05) but became insignificant thereafter. Improvement in BCVA was superior in the low-fluence PDT group, but the differences were not statistically significant except at month three (P = 0.025).
On indocyanine green angiography, a significantly greater proportion of the low-fluence PDT group (16 eyes; 88.9 percent) showed a marked reduction in choroidal hyperpermeability after primary treatment than in the ranibizumab group (zero eyes; P < 0.001). No serious adverse events related to the drugs or procedures were observed.
The authors write that although the efficacy of ranibizumab injections did not reach the level seen for low-fluence PDT, ranibizumab monotherapy induced cessation of active leaks from the retinal pigment epithelium level along with a significant improvement in visual acuity in several patients.
They also note that in one low-fluence PDT–treated eye with persistent subretinal fluid, rescue ranibizumab treatment led to the regression of fluorescein leakage and fluid. This suggests that ranibizumab can be effective in select patients, although its benefit is not long lasting compared with low-fluence PDT. In some cases, the response to ranibizumab treatment might indicate an unrevealed underlying choroidal neovascularization component.