Central Serous Chorioretinopathy Treated by Modified Photodynamic Therapy
Condition: Central Serous Chorioretinopathy
MeSH terms: Central Serous Chorioretinopathy
Study type: Interventional

Summary: 
      The purpose of this study is to evaluate the effectiveness as well as the detrimental
      influence of half-dose and half-fluence modification of verteporfin photodynamic therapy
      (PDT) for the treatment of prolonged unresolved central serous chorioretinopathy (CSCR).
    

Detailed description: 
      Purpose:

      to evaluate the effectiveness as well as the detrimental influence of half-dose and
      half-fluence modification of verteporfin PDT for the treatment of prolonged unresolved
      Central Serous Chorioretinopathy (CSCR).

      Study Design and Patient Recruitment:

      This study was a prospective, randomized, consecutive, open-labeled, comparative
      interventional case series. Patients with symptomatic acute or chronic CSC of 3 weeks or more
      duration were recruited. Patients were offered treatment if they had worsening of symptoms or
      no subjective improvement since the onset of the CSC. Inclusion criteria included 1) patients
      with best-corrected visual acuity (BCVA) of 20/400 or better; 2) presence of subretinal fluid
      (SRF) and/or serous pigment epithelial detachment (PED) involving the fovea on optical
      coherence tomography (OCT); 3) presence of active angiographic leakage in fluorescein
      angiography (FA) caused by CSC but not CNV or other diseases; and 4) abnormal dilated
      choroidal vasculature and other features in ICGA consistent with the diagnosis of CSC.
      Patients who received previous PDT or focal thermal laser photocoagulation for the treatment
      of CSC or had evidence of CNV, polypoidal choroidal vasculopathy, or other maculopathy on
      clinical examination, FA, or ICGA were excluded. Informed consent was obtained from all
      subjects. 12 patients in each group were planned to recruit in each group.

      Modified Photodynamic Therapy with Half Dosage:

      The Half Dosage PDT protocol for CSC was performed using half the normal dose of verteporfin
      (Visudyne, Novartis AG, Bülach, Switzerland) i.e., 3 mg/m2 infusion of verteporfin with a
      rationale that using lower dosage has less collateral damaging effects to the retina and
      choroid. Verteporfin was infused over 10 minutes followed by delivery of laser at 692 nm at
      15 minutes from the commencement of infusion to target the area of choroidal dilation and
      hyperpermeability. Earlier laser application allowed less drug accumulation at the RPE layer
      and less drug less toxicity at the RPE. A total light energy of 50 J/cm2 over 83 seconds was
      delivered to the area of choroidal hyperperfusion as observed in ICGA instead of the
      angiographic leakage sites shown in FA. Only the area of choroidal vascular abnormality that
      was supposed to cause the serous detachment involving the macula was considered to be
      treated. To avoid overtreatment on the choroidal vasculature in causing choroidal ischemia,
      the laser spot size was set at a maximum of 4,500 µm. This restriction in laser spot size is
      adequate, from our previous report, to reverse the serous macular detachment by reducing the
      choroidal extravascular leakage and sub-RPE hydrostatic pressure at the macular area. In
      patients with bilateral CSC, only one eye was recruited for the study, and the eye with
      thicker central retinal thickness on OCT was chosen. After treatment, patients were given
      protective spectacles and instructed to avoid strong light for 3 days.

      Modified Photodynamic Therapy with Half fluence:

      The Half fluence PDT protocol for CSC was performed using half the normal duration of
      verteporfin laser time (Visudyne, Novartis AG, Bülach, Switzerland) All patients received a
      bolus infusion of 6 mg/m2 body surface area over 1 minute. Patients were assigned to
      treatment protocols, using a fluence of 25 J/cm2. In the 25-J/cm2 group, patients received an
      irradiance of 600 mW. Depending on the irradiance, the time of photosensitization was 42
      seconds. A total light energy of 25 J/cm2 over 42 seconds was delivered to the area of
      choroidal hyperperfusion as observed in ICGA instead of the angiographic leakage sites shown
      in FA. Only the area of choroidal vascular abnormality that was supposed to cause the serous
      detachment involving the macula was considered to be treated. To avoid overtreatment on the
      choroidal vasculature in causing choroidal ischemia, the laser spot size was set at a maximum
      of 4,500 µm. This restriction in laser spot size is adequate, from our previous report, to
      reverse the serous macular detachment by reducing the choroidal extravascular leakage and
      sub-RPE hydrostatic pressure at the macular area. In patients with bilateral CSC, only one
      eye was recruited for the study, and the eye with thicker central retinal thickness on OCT
      was chosen. After treatment, patients were given protective spectacles and instructed to
      avoid strong light for 3 days.

      Documentation:

      Patients were seen for regular follow-up visits within 1 week before and at day 1, week 1,
      week 4, and month 3 after treatment. A standardized evaluation was performed at each visit
      including best corrected visual acuity according to the guidelines of the Early Treatment
      Diabetic Retinopathy Study (ETDRS), confocal scanning laser fluorescein angiography (FA),
      ICGA (Heidelberg Engineering, Dossenheim, Germany), fundus photography, and a complete eye
      examination. Selected patients were imaged with optical coherence tomography (OCT).

      The main outcome measures were choroidal perfusion changes, as documented by early and late
      ICGA. A PDT-induced increase in collateral leakage area seen by late FA 1 day after PDT was
      defined as a secondary outcome, as was primary CNV closure documented by early FA.
      Best-corrected visual acuity was documented for safety evaluation. Data were statistically
      analyzed with the Wilcoxon signed-rank and Wilcoxon rank sum tests. Statistical significance
      was defined as P <0.05.

      Procedures for Evaluation:

      The Image J, (software ; NIH, USA), an imaging software developed for analysis and
      visualization of images obtained with grayscale photograph, was used forplanimetric
      evaluation of the area of hypofluorescence detected by ICGA and the area of PDT-induced
      leakage seen on FA. Choriocapillary hypoperfusion and nonperfusion were graded according to a
      scale. Angiographies were evaluated by two masked readers, and planimetricand grading results
      of both readers were averaged.

      Follow-Up Examinations:

      Patients were assessed at baseline and followed at day 1, 7, 30, 90 and 180 after PDT. At the
      baseline and post-PDT visits, BCVA was measured by certified optometrists with the Early
      Treatment Diabetic Retinopathy Study (ETDRS) logarithm of the minimum angle of resolution
      (logMAR) chart at 4 m or Snellen chart at 6 m being converted to logMAR equivalent for
      analysis. OCT recordings were performed using an OCT 3 machine (StratusOCT, Carl Zeiss
      Meditec Inc., Dublin, CA). Both vertical and horizontal scans of 6.0 mm centered on the fovea
      were obtained for measurement of central foveal thickness. OCT central foveal thickness was
      measured manually using the retinal thickness mode and is defined as the distance between the
      inner surface of the RPE and the inner surface of the neurosensory retina at the fovea. FA
      and ICGA were performed in all patients at baseline, month 1, and 3 after PDT. Additional FA
      and ICGA were carried out in patients with persistence or recurrence of CSC during the
      follow-up period. CSC was classified according to FA findings into two groups: 1) chronic CSC
      with serous retinal detachment and focal leakage (Group 1); or 2) chronic CSC with diffuse
      leakage that had an RPE transmission defect in early phase and diffuse angiographic leakage
      in mid to late phases (Group 2). Features of CSC in ICGA were delineated according to the
      original descriptions.

      Data Analysis:

      The main outcome measures of the study included the serial changes in logMAR BCVA and OCT
      central foveal thickness. Other outcome measures included complications and FA and ICGA
      changes during the follow-up period. Serial comparisons of mean logMAR BCVA and OCT central
      foveal thickness were performed using the nonparametric Wilcoxon-signed rank test and
      two-tailed t-test, respectively. Categorical variables were analyzed using the chi-square
      test and Fisher exact test. Statistical analysis was performed using SPSS and a P value of
      <=0.05 was considered statistically significant.
    

Intervention name(s): Verteporfin PDT, half-dose; verteporfin PDT, half-fluence
Intervention type(s): Drug; Drug
Intervention description(s): half the regular dose or half the regular laser fluence to treat prolonged unresolved CSCR; half the regular dose or half the regular laser fluence to treat prolonged unresolved CSCR
Other intervention name(s): visudyne; visudyne
Intervention MeSH terms: Verteporfin
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: chorioretinopathy; photodynamic therapy; reduced fluence; reduced dose