We retrospectively reviewed medical records and images from patients who received half-dose PDT or one-third-dose PDT for chronic or recurrent CSC between January 2012 and December 2017 at the Department of Ophthalmology, Songklanagarind Hospital, PSU, Songkhla Province, Thailand. Our study was approved by the Institutional Review Board of Songklanagarind Hospital, PSU, and adhered to the guidelines of the Declaration of Helsinki.
We classified CSC into two types; chronic CSC was defined based on symptoms persisting more than 3 months, and recurrent CSC was defined based on new symptoms in the same eye or the fellow eye of a patient with visual deficits from an earlier episode of CSC.
The inclusion criteria were as follows: (1) age between 20 and 70 years; (2) chronic or recurrent CSC that was treated with half-dose PDT or one-third-dose PDT; (3) presence of SRF involving the macula, as evident on spectral-domain optical coherence tomography (SD-OCT); and (4) the presence of active leakage on fluorescein angiography (FA).
The exclusion criteria were as follows: (1) previous PDT or intravitreal injections of anti-vascular endothelial growth factor (VEGF) or steroids; (2) previous intraocular surgery; (3) other macular abnormalities, such as CNV, polypoidal choroidal vasculopathy (PCV) or other maculopathy; and (4) follow-up of less than 12 months, or missing data such as best-corrected visual acuity (BCVA) or OCT images at baseline, or 1, 3, 6 or 12 months after treatment.
The data collected included: patient sex, age, weight, height, laterality of visual impairment, duration of symptoms, type of CSC, leakage type of CSC on FA, spot size of PDT treatment, BCVA and CRT at baseline and at 1, 3, 6 and 12 months after treatment. The data were recorded from electronic medical records with the hospital information system, at the Department of Ophthalmology, Faculty of Medicine, PSU, Songkhla Province, Thailand.
The main outcome measures were the improvement in BCVA and CRT, and the presence of SRF at the 1-, 3-, 6- and 12-month follow-ups after PDT treatment. Evaluation of macular detachment and CST were performed using an SD-OCT machine [(Spectralis®, Heidelberg Engineering, Heidelberg, Germany) or (Cirrus OCT®, Carl Zeiss Meditec, Inc., Dublin, CA)]. All patients underwent simultaneous FA and indocyanine green angiography (ICGA) [Heidelberg retinal angiography, Heidelberg Engineering, Heidelberg, Germany] at baseline, for confirmation of the diagnosis and planning of the PDT treatment.
PDT was performed by administering a half-dose (3 mg/m2) or one-third-dose (2 mg/m2) of verteporfin (Visudyne®, Novartis AG, Basel, Switzerland). Verteporfin was infused for 8 minutes. The laser (wavelength 689 nm, with total light energy of 50 J/cm2 for 83 s) was delivered to the area of angiographic leakage observed on FA with an associated area of choroidal hyperpermeability on ICGA at 10 minutes after infusion. After treatment, all patients were instructed to avoid sunlight for 48 hours. Informed consent for PDT was obtained from each patient after a discussion of the potential risks and benefits.
Statistical analysis was performed using SPSS (version 11.0, SPSS Inc, Chicago, IL). Independent-sample t-tests were used to compare BCVA, CRT and SRF-recurrence rate between the two dosage groups. Within each group, the changes in BCVA and CRT were investigated using paired-sample t-tests. P-values of < 0.05 were considered statistically significant.