RETINAL DISORDERS Comparison of half-dose photodynamic therapy and 689 nm laser treatment in eyes with chronic central serous chorioretinopathy Andrea Russo 1 & Raffaele Turano 1 & Francesco Morescalchi 1 & Elena Gambicorti 1 & Anna Cancarini 1 & Sarah Duse 1 & Ciro Costagliola 2 & Francesco Semeraro 1 Received: 8 November 2016 /Revised: 30 January 2017 /Accepted: 21 February 2017 # Springer-Verlag Berlin Heidelberg 2017 Abstract Purpose To compare visual and anatomical outcomes be- tween half-dose photodynamic therapy (hd-PDT) and 689 nm laser therapy (689-LT) in chronic central serous chorioretinopathy (CSC). Methods Forty eyes of 40 patients with symptomatic chronic CSC were randomized in a 1:1 ratio to receive either hd-PDT or 689-LT delivering 95 J/cm 2 via an intensity application of 805 mW/cm 2 over 118 s. Best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography findings were compared between the two treatment groups. Results Mean CSC duration was 17.1 ± 6.66 weeks and 18.7 ± 7.46 weeks in the hd-PDT and 689-LT groups respectively. Both groups showed significant BCVA improvements, as well as reductions in central retinal and subfoveal choroidal thick- ness. Although hd-PDT led to a faster reduction in central retinal thickness, no significant differences were recorded be- tween groups for any other measured parameter at any time point. Complete photoreceptor recovery was observed in eight and seven eyes in the hd-PDT and 689-LT groups respectively. Conclusions Both hd-PDT and 689-LT were effective at treating chronic CSC. Further studies are warranted to evaluate long-term safety and efficacy. Keywords Central serous chorioretinopathy . Laser treatment . Photodynamic therapy . Subthreshold micropulse laser Introduction Central serous chorioretinopathy (CSC) is characterized by an idiopathic serous detachment of the neurosensory retina sec- ondary to defects in the retinal pigment epithelium (RPE) [1]. CSC can be distinguished into two main subtypes: acute and chronic CSC (cCSC). In acute CSC, the detachment is caused by a focal leak (Bhot spot^) in the RPE, and the subretinal fluid (SRF) is usually self-limiting with good recovery of visual function. However, 33–50% of cases can experience recur- rence, with long-standing areas of neurosensory detachment leading to permanent visual impairment [2]. In these cases, patients show irregular mildly atrophic RPE changes and cho- roidal abnormalities that often occur without a single focal Bhot spot^ but experience more diffuse leakage. The duration of cCSC is inconsistent among studies; in some it has been defined as 3 months [3], while in others it was 6 months [4]. We defined the duration of cCSC as at least 3 months in the present study. Treatment options include conventional focal laser, pho- todynamic therapy (PDT), intravitreal anti-vascular endothe- lial growth factor, and subthreshold micropulse yellow laser (SM) [4, 5]. SM dispenses energy in bursts of micropulses, instead of a single pulse, thereby minimizing thermal dam- age to the target tissue and surrounding structures [6]. A thermal stress is also reported in transpupillary thermotherapy (TTT) [7], and elicits the production of heat- shock proteins (HSP) [8]; this appears to be effective at repairing RPE cells, restoring their viability, and returning them to a more normal functional state [9]. * Andrea Russo dott.andrea.russo@me.com 1 Eye Clinic, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Piazzale Spedale Civili, 1, 25100 Brescia, Italy 2 Department of Medicine and Health Sciences, University of Molise, Campobasso, Italy Graefes Arch Clin Exp Ophthalmol DOI 10.1007/s00417-017-3626-9