Optical Coherence Tomographic Angiography Manifestations And Changes After Half-Dose Photodynamic Therapy In Central Serous Chorioretinopathy

Background and ObjectiveCentral serous chorioretinopathy(CSC)is a common macular disease which is characterized by serous detachment of posterior polar of retina and can be accompanied by detachment of retinal pigment epithelium(RPE).CSC often occurs in young people between 20 and 50 years old but it can also affect children and the elderly people.The incidence rate for male was higher than the female.The clinical manifestations are sudden visual decline,darkening,metamorphopsia and micropsia and it can occur in one eye or both eyes.The pathogenesis remains still uncertain Studies have shown that the incidence of CSC is related to the increase of catecholamine concentration in serum.Furthermore,it is related to exogenous and endogenous glucocorticoids level.We can see the reflection of macular fovea disappears and round or similar round a little bit grey eminence lesions by fundus examination.It is usually self-resolving over 3-6 months in a majority of the patients but there is the possibility of recurrence.CSC can be divided into acute and chronic types according to the duration of the disease.Chronic CSC is usually defined as persistence of disease for at least 3-6 monthsCSC is a kind of chorioretinopathy.People believed primary lesions of CSC is in RPE cells at first.Fluorescein leakage points can be seen on Fluorescence fundus angiography(FFA).Choroidal diseases are better understood after indocyanine green angiography(ICGA)has been invented.Scholars speculate that changes in RPE in CSC patients might be caused by pathological changes in choroidal blood vessels because ICGA shows dilation and hyperpermeability of choroidal vessels.At present FFA and ICGA are the gold standards for diagnosing CSC and ICGA is used for guideing photodynamic therapy(PDT).FFA and ICGA are invasive.Some patients can't tolerate to the dye and it may even cause some serious complications.Optical coherence tomography angiography(OCTA)is a noninvasive new technique which was invented in recent years.It is more convenient and efficient than conventional angiography.OCTA can clearly display the vascular morphology of retina and choriod by built-in algorithm and it allows researchers to observe images layer by layer Furthermore,data can also be provided through the built-in software.So OCTA provides a new tool for the study of CSC and other choroidal vascular diseases.Even though CSC is a self-limiting disease,patinets with long duration need active intervention.Currently,in addition to drug therapy,there are thermal laser and PDT and a large number of studies have confirmed that PDT has a good therapeutic effect on CSC.This research analysis OCTA manifestations in CSC and compares them with FFA and ICGA.OCTA and choroidal thickness are compared before and after half-dose PDT treatment and these differences between CSC patients and healthy people.We want to use these methods to explore the clinical application value of OCTA in CSCMethodsThis retrospective study included 31 eyes of 29 CSC patients of whom 12 eyes of 11 patients accepted half-dose PDT therapy.We selected eleven healthy subjects(12 eyes)with no significant difference in age and gender from PDT group as normal control group.Best corrected visual acuity(BCVA),FFA,ICGA,OCT and OCTA were performed in all patients.We observed the manifestations of OCTA in CSC and compared OCTA with FFA and ICGA.And we analyzed the differences of vessel density of superficial capillary plexus(SCP)and deep capillary plexus(DCP),flow area of choriocapillaris,area of foveal avascular zone(FAZ),subfoveal choroidal thickness(SCT),inner and outer layers of subfoveal choroid between PDT group and control group.ResultsA total of 29 CSC patients(31 eyes)were enrolled in this study.11 patients(12 eyes)accepted half-dose PDT therapy and 11 healthy people(12eyes)were selected as control group.1.Correlations between FFA,ICGA and OCTA:all examed eyes' leakage points or high fluorescence of early phase of FFA and/or ICGA corresponding to increased flow signals at choriocapillary of OCTA.After PDT therapy signals of these areas decreased.2.Correlations between subretinal fluid(SRF)area and OCTA:all eyes of paitents showed areas of OCTA decreased flow signals at choriocapillary corresponding to the areas of SRF before therapy and eyes of which accepted half-dose PDT showed decreased signals increasing after therapy.3.Comparing PDT group with control:before PDT the SCT of PDT group was 415.25±41.95?m which after therapy was 336.33±74.8?m.SCT of control group was 241.5±77.01?m.SCT of PDT group was significantly higher than that in control group no matter before or after therapy(P<0.01,<0.01).SCT of patients dramatically decreased after half-dose PDT(P<0.01).Thickness of inner layer of subfoveal choroid before therapy,after therapy and in contol group were 62.67±10?m,62.92±8.04?m and 76.92±18.7?m respectively.Thickness of inner layer of subfoveal choroid of PDT group was significantly lower than that in control group no matter before or after therapy(P<0.05,<0.05).It had no significant change before and after therapy(P>0.05).Thickness of outer layer of subfoveal choroid before therapy,after therapy and in contol group were 352.58±40.59?m,273.4±70.86?m and 164.5±61.86?m respectively.Thickness of outer layer of subfoveal choroid of PDT group was significantly haigher than that in control group before and after therapy(P<0.01,<0.01).Thickness of outer layer of subfoveal choroid of patients dramatically decreased after therapy(P<0.01,<0.01).After therapy vessel density of SCP and DCP and area of FAZ revealed no statistical difference compared to that before therapy and control group.Choriocapillaris flow area before therapy,after therapy and in contol group were 9.76±0.58mm2,10.09±0.81mm2 and 10.83±0.54mm2 respectively.Before therapy it was significantly less than control group(P<0.01).Choriocapillaris flow area of patients had no significant change after therapy(P>0.05)and still less than control(P<0.05).4.The relationship between choriocapillaris flow area and age,BCVA and choriodal thickness:in the multivariate analysis,the thickness of outer layer of subfoveal choroid showed negative linear correlation with the choriocapillaris flow area in CSC(P=0.03).ConclusionAs a new imaging technique,OCTA has certain clinical practical value for the diagnosis,treatment and therapeutic effect evaluation of CSC.