Selective Retina Therapy With Real-Time Feedback-Controlled Dosimetry for Treating Acute Idiopathic Central Serous Chorioretinopathy in Korean Patients
Condition: Central Serous Chorioretinopathy
MeSH terms: Central Serous Chorioretinopathy
Study type: Interventional

Summary: 
      Selective retina therapy (SRT) selectively disrupts the retinal pigment epithelium (RPE) with
      minimal damage to the photoreceptors. Previous studies have shown SRT to be effective for
      resolving SRF, while causing only minimal collateral damage to the retina and vision.However,
      most patients included in prior studies had chronic CSC (≥3 months symptom duration) and SRT
      efficacy on acute CSC is not fully known.

      The current study evaluated short-term treatment outcomes following SRT with real-time
      feedback-controlled dosimetry in Korean patients with acute idiopathic CSC.
    

Detailed description: 
      Central serous chorioretinopathy (CSC) is a disorder that is characterized by a localized
      serous detachment of the neurosensory retina in the posterior pole. Additionally, CSC is
      often self-limiting and spontaneous resolution of subretinal fluid (SRF) often occurs within
      several months. Although several treatment modalities (e.g., laser photocoagulation,
      photodynamic therapy, and anti-vascular endothelial growth factor [VEGF] therapy have been
      used in CSC patients, a consensus has not yet been reached on the optimal time for
      intervention.

      Selective retina therapy (SRT) selectively disrupts the retinal pigment epithelium (RPE) with
      minimal damage to the photoreceptors. Previous studies have shown SRT to be effective for
      resolving SRF, while causing only minimal collateral damage to the retina and vision.
      However, most patients included in prior studies had chronic CSC (≥3 months symptom duration)
      and SRT efficacy on acute CSC is not fully known.

      When treating CSC patients, it is generally recommended to follow-up several months without
      any intervention to identify spontaneous resolution of SRF. However, prompt treatment may be
      beneficial for some patients. For example, metamorphopsia or micropsia associated with CSC
      can greatly interfere with driving or with work when an occupation requires delicate
      procedures. Additionally, patients are often psychologically distressed by a CSC diagnosis
      and the accompanying decrease in vision-related quality of life. In these cases, prompt
      treatment to reduce SRF may relieve, at least in part, CSC symptoms and their related stress.

      The current study evaluated short-term treatment outcomes following SRT with real-time
      feedback-controlled dosimetry in Korean patients with acute idiopathic CSC.

      This study included patients who were diagnosed with treatment-naïve idiopathic CSC and were
      treated with SRT. The R:GEN device (Lutronic, Goyang-si, South Korea) was used to administer
      SRT. Inclusion criteria also included SRF involving the fovea (documented by optical
      coherence tomography [OCT] performed at initial presentation) and symptom duration shorter
      than 3 months. Patients were excluded from analyses if any of the following were true: (1)
      age > 55 years, (2) clinical or angiographic features suggestive of choroidal
      neovascularization, (3) OCT findings suggestive of type 1 neovascularization or polypoidal
      choroidal vasculopathy (e.g., double layer sign or fibrovascular pigment epithelial
      detachment), (4) history of macular laser photocoagulation, photodynamic therapy, or
      anti-VEGF therapy, or (5) history of exogenous corticosteroid treatment for a systemic
      disease (e.g., Cushing's syndrome or renal disease).

      Examination, treatment, and follow-up All subjects underwent comprehensive ophthalmologic
      examinations, including best-corrected visual acuity (BCVA) measurement, slit-lamp
      biomicroscopy (90-diopter lens), fluorescein angiography (FAG), fundus photography, and
      spectral domain OCT (Spectralis HRA-OCT™, Heidelberg Engineering, Dossenheim, Germany or RS
      3000™, Nidek Co., Ltd., Tokyo, Japan). Indocyanine green angiography using a confocal
      laser-scanning system (Spectralis HRA-OCT™) was performed at the discretion of each
      physician. A CSC diagnosis was based on FAG findings, in particular, evidence of a typical
      ink blot or smokestack leakage. A single examiner (J.H.K.) reviewed all FAG results.

      All SRT was performed by a single physician (J.H.K.) using a Nd:YLF laser (wavelength of 257
      nm, 15 micro pulses per spot, single micro pulse duration of 1.7 µs, pulse repetition rate of
      100 Hz). Spot size was set at a diameter of 200 µm. Real-time feedback-controlled dosimetry
      (RFD) detects ultrasonic pressure waves generated by intracellular bubble formation and was
      used to determine optimal laser energy. Before applying laser energy to a leakage point, test
      shots were made immediately outside of the superior or inferior temporal arcade.

      Optimal laser energy was determined based on real-time feedback system indications on the
      control panel. Laser energy began at 80 µJ and was increased in 5-10 µJ intervals until the
      optimal energy delivery was confirmed by the RFD system. Following confirmation, the optimal
      laser energy was applied to fluorescein leakages. If the energy was indeed optimal at leakage
      points, laser shots were administered around the leakages. If the energy was not optimal at
      the leakage points, laser energy was again increased in 5-10 µJ increments until optimal
      energy delivery, as confirmed by the RFD system. If the control panel indicated that
      excessive laser energy had been applied, the laser energy was decreased in 5-10 µJ increments
      until the optimal energy delivery was again achieved (confirmed by RFD system). The total
      number of laser shots delivered around fluorescein leakage points that were at or above the
      optimal laser energy were counted.

      Patients had follow-up visits 1 and 3 months after SRT, at which BCVA was measured and OCT
      examination was performed. Central foveal thickness (CFT) was manually measured on OCT images
      and was defined as the distance between the RPE and the internal limiting membrane.

      Outcome measures Both BCVA and CFT were measured at diagnosis, at 1 and 3 months following
      SRT, and at the final follow-up visit. The incidence of complete SRF resolution was
      estimated. Color fundus photographs taken at each follow-up visit also documented laser
      treatment and were used to check for the presence of visible laser spots. All BCVA
      measurements were converted to the logarithm of the minimum angle of resolution (logMAR) for
      data analyses.

      Statistical analyses Statistical analyses were performed using a commercially available
      software package (SPSS v. 12.0 for Windows; SPSS Inc., Chicago, IL). Comparisons between BCVA
      and CFT measurements at different time points were performed using Wilcoxon signed-rank tests
      with a Bonferroni correction. Statistical significance was defined as P ≤ 0.05.
    

Intervention name(s): Selective retina therapy
Intervention type(s): Device
Intervention description(s): The selective retina therapy (SRT) is a laser treatment to the retina using the R:GEN device (Lutronic, Goyang-si, South Korea).
Laser energy began at 80 µJ and was increased in 5-10 µJ intervals until the optimal energy delivery was confirmed by the RFD system. Following confirmation, the optimal laser energy was applied to fluorescein leakages. If the energy was indeed optimal at leakage points, laser shots were administered around the leakages. If the energy was not optimal at the leakage points, laser energy was again increased in 5-10 µJ increments until optimal energy delivery.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment