Purpose
To compare the efficacy and safety of half-fluence vs half-dose photodynamic therapy (PDT) in chronic central serous chorioretinopathy (CSC).
Design
Multicenter retrospective comparison study.
Methods
Retrospective review of 56 patients affected by chronic CSC, including 28 patients (31 eyes) who received half-fluence PDT and 28 patients (29 eyes) who received half-dose PDT. Best-corrected visual acuity (BCVA), central foveal thickness (CFT), and resolution of subretinal fluid on optical coherence tomography at 1 and 12 months were assessed.
Results
The mean logMAR BCVA improved significantly ( P < .001), both in the half-fluence group (from 0.187 [± 0.187] to 0.083 [± 0.164]) and in the half-dose group (from 0.126 [± 0.091] to 0.068 [± 0.091]), at 12 months, without significant difference between the 2 groups. At 1 month a complete resolution of subretinal fluid was observed in 19 half-fluence-treated eyes (61.3%) and in 25 half-dose-treated eyes (86.2%) ( P = .04). At 12 months, a complete resolution of subretinal fluid was achieved in 26 half-fluence-treated eyes (83.9%) and 29 half-dose-treated eyes (100%) ( P = .0529). Nine eyes (29%) in the half-fluence group and 5 eyes (17.2%) in the half-dose group had at least 1 recurrence of subretinal fluid during the follow-up. Overall there were 15 and 5 recurrences in the half-fluence PDT and half-dose PDT groups, respectively ( P = .07). In no eye of either groups was atrophy of the retinal pigment epithelium observed in the area of treatment.
Conclusion
Half-dose PDT induced a more rapid reabsorption of the fluid, a more lasting effect, and equal safety with respect to half-fluence PDT.
Central serous chorioretinopathy (CSC) is characterized by idiopathic neurosensory retinal detachment at the posterior pole with subretinal fluid coming from the choroid. In the majority of patients, CSC is self-limiting and patients usually have a good visual prognosis. However, in cases of chronic persistence of foveal detachment or posterior cystoid retinal degeneration, progressive visual loss attributable to photoreceptor damage and, finally, foveal atrophy may develop. Although there are no phase 3 randomized clinical trials, photodynamic therapy (PDT) is now considered the treatment of choice for chronic CSC. However, the parameters are not standardized yet. Halving the dosage of verteporfin or the fluence showed similar results compared to standard PDT in term of reabsorption of the subretinal fluid and visual outcome, with significant fewer adverse events. Half-fluence and half-dose PDT have been supposed to cause less ischemia at the level of the retinal pigment epithelium (RPE)/choriocapillaris and then to be safer with respect to standard PDT. Both of these treatment procedures are actually used, and there are no data to prefer one to the other. We hypothesize that the 2 modalities of treatment may have not identical effects on the chorioretinal tissue and therefore may be different in terms of safety and efficacy. So far no studies have been performed that compared the 2 treatments. The purpose of this study is to compare the efficacy and safety of half-fluence PDT vs half-dose PDT for the treatment of chronic CSC.
Methods
Retrospective review of medical records of 56 patients who had received PDT at the University Eye Clinics of Genova and Torino, Italy, in the last 2 years was conducted. The Institutional Review Board of the University of Genova and Torino approved the study protocol and the collection of data related to all the patients affected by CSC and treated by PDT. The data collection complies with Italian law. The study was conducted in accordance with the provisions stated in the Declaration of Helsinki. Informed consent for PDT was obtained from all patients.
Patients were offered treatment if they had chronic disease with fluid involving the central macula. CSC was defined as chronic when subretinal fluid persisted for 6 months or more. Inclusion criteria were: (1) symptoms for at least 6 months; (2) Snellen best-corrected visual acuity (BCVA) of 20/200 or better; (3) presence of subretinal fluid involving the fovea; and (4) presence of active leakage on fluorescein angiography (FA). Eyes with other chorioretinal disorders that can produce subretinal exudation were excluded. Cases of CSC with posterior cystoid retinal degeneration with judgment based on optical coherence tomography (OCT) and FA were also excluded, as well as patients who had already received laser photocoagulation, PDT, or anti–vascular endothelial growth factor intravitreal injections. BCVA was measured at the baseline and post-PDT visits using the ETDRS charts by certified examiners. Vision results were quantified as logMAR units. Evaluation of macular detachment was performed using a spectral-domain OCT machine (Topcon 3D OCT-1000; Optovue RTVue, Fremont, California USA). Central foveal thickness was measured by way of the 12-radial scan protocols at baseline and at 1 and 12 months. Indocyanine green angiography (ICGA) was performed in all patients in order to outline choroidal hyperpermeability areas and be a guide for treatment. Patients were examined with OCT at 1 month after PDT and then every 3–4 months. FA and ICGA were performed in all patients at baseline and during the follow-up in case of persistence or recurrence of the subretinal fluid.
PDT was performed by administering half the normal fluence (25 J/cm 2 ) or half the normal dose (3 mg/m 2 ) of verteporfin (Visudyne; Novartis AG, Basel, Switzerland) as previously described. Verteporfin was infused over 10 minutes followed by 83 seconds delivery of laser at 693 nm 15 minutes after the start of the infusion to target the area of choroidal hyperpermeability. Areas of choroidal vascular abnormality that were supposed to cause the serous detachment were considered to be treated. Retreatments were performed not earlier than 3 months after the previous treatment in case of persistence or recurrence of subretinal fluid. Half-dose PDT was used when 2 or more patients were treated in the same day. Half-fluence PDT was performed in the other cases.
Results
Thirty-one eyes (28 patients) received half-fluence PDT and 29 eyes (28 patients) received half-dose PDT. The baseline demographic data of both groups are shown in Table 1 . There were no significant differences between the 2 groups. At baseline, the mean (SD) logMAR BCVA was 0.187 (± 0.187) in the half-fluence group and 0.126 (± 0.091) in the half-dose group. At the last follow-up visit, mean (SD) logMAR BCVA was 0.083 (± 0.164) in the half-fluence group and 0.068 (± 0.091) in the half-dose group. At baseline, mean logMAR BCVA in the half-fluence group compared to the half-dose group was not statistically different ( P > .1, unpaired t test) ( Table 2 ). At 12 months, mean logMAR BCVA in the half-fluence group compared to the half-dose group was not statistically different ( P > .1, unpaired t test). There was a statistically significant difference between baseline and 12 months mean logMAR BCVA in the half-fluence group as well as the half-dose group ( P < .001, paired t test) ( Table 2 ). In no eye was reduction of BCVA observed after the treatment.
| Half-Fluence (n = 31) | Half-Dose (n = 29) | P Value | |
|---|---|---|---|
| Mean age ± standard deviation (y) | 49.4 ± 11.3 | 48.6 ± 9.7 | .7 a |
| Sex (male/female) | 26/5 | 24/4 | .9 b |
| Mean follow-up ± standard deviation (months) | 15.34 ± 7.8 | 17.34 ± 5.91 | .06 a |
| Mean ± standard deviation logMAR best-corrected visual acuity (Snellen equivalent) | 0.187 ± 0.187 (20/28) | 0.126 ± 0.091 (20/26) | .1 a |
| Mean ± standard deviation central foveal thickness (μm) | 304.9 ± 68.7 | 342 ± 107 | .1 a |
| Logmar Best Corrected Visual Acuity (Snellen Equivalent) | Central Foveal Thickness (standard deviation, μm) | |||||
|---|---|---|---|---|---|---|
| Half-fluence | Half-dose | P b | Half-fluence | Half-dose | P b | |
| Baseline | 0.187 ± 0.187 (20/28) | 0.126 ± 0.091 (20/26) | >.1 | 304.4 (± 69.74) | 342.0 (± 107.1) | .1 |
| 12 months | 0.083 ± 0.164 (20/23) | 0.068 ± 0.091 (20/23) | >.1 | 241.5 (± 28.94) | 200.5 (± 34.95) | <.0001 |
| P a | <.001 | <.001 | <.001 | <.001 | ||
Complete resolution of subretinal fluid was observed at 1 month in 19 half-fluence-treated eyes and in 25 half-dose-treated eyes (61.3% vs 86.2%; P = .04, Fisher exact test). At 12 months, 26 eyes in the half-fluence group and 29 eyes in the half-dose group showed a complete resolution of subretinal fluid (83.9% vs 100%; P = .0529, Fisher exact test). At baseline, the mean (SD) central foveal thickness was 304.4 (± 69.74) μm in the half-fluence group and 342.0 (± 107.1) μm in the half-dose group ( P = .1). At 12 months, the mean (SD) central foveal thickness was 241.5 (± 28.94) μm in the half-fluence group and 200.5 (± 34.95) μm in the half-dose group. At baseline, mean central foveal thickness in the half-fluence group compared to the half-dose group did not show a statistically significant difference ( P = .1, unpaired t test) ( Table 1 ). At 12 months, mean central foveal thickness in the half-fluence group compared to the half-dose group showed a statistically significant difference ( P < .0001, unpaired t test). Comparison between baseline and 12 months mean central foveal thickness was statistically different in the half-fluence group as well as the half-dose group ( P < .001, paired t test) ( Table 2 ). The mean extent of reduction was significantly greater using the half-dose PDT.
The mean number of PDT required were 1.48 and 1.17 ( P = .49, Fisher exact test) in the half-fluence and half-dose group, respectively. Nine of 31 eyes (29%) in the half-fluence group and 5 of 29 eyes (17.2%) in the half-dose group had at least 1 recurrence of subretinal fluid. Overall there were 15 and 5 recurrences in the half-fluence group and half-dose group, respectively ( P = .07; Fisher exact test). In the half-fluence group 5 eyes had 1 recurrence, 2 eyes had 2 recurrences, and 2 eyes had 3 recurrences. In the half-dose group 5 eyes had a recurrence only 1 time. In addition to the baseline treatment, the half-fluence PDT group needed 15 more sessions while the half-dose PDT group needed 5 more sessions ( P = .49; Fisher exact test). Analysis of fundus photographs and fluorescein angiograms taken during the follow-up did not show atrophic changes of the RPE in the area of PDT application in any case.
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