If there are defects in the retinal pigment epithelium without accumulation of fluid below the retina, a pachychoroid pigmentepitheliopathy (PPE) is present. Accumulation of fluid results in central serous chorioretinopathy (CSR). The development of secondary blood vessels, so-called choroidal neovascularization (CNV) leads to pachychoroid neovasculopathy (PNV). If parts of these new vessels bulge outward, so-called aneurysms develop within this CNV, defining pachychoroid aneurysmal type 1 CNV (or, still widely used, polypoidal choroidal vasculopathy (PCV)). Since the individual stages develop one after the other from the respective preliminary stage, pachychoroidal diseases of the macula are divided into 4 stages according to Siedlecki, Schworm and Priglinger:

Risk factors
CSR is sometimes called idiopathic CSR which means that its cause is unknown. Nevertheless, stress appears to play an important role. An oft-cited but potentially inaccurate conclusion is that persons in stressful occupations, such as airplane pilots, have a higher incidence of CSR. CSR has also been associated with cortisol and corticosteroids. Persons with CSR have higher levels of cortisol. Cortisol is a hormone secreted by the adrenal cortex which allows the body to deal with stress, which may explain the CSR-stress association. There is extensive evidence to the effect that corticosteroids (e.g. cortisone), commonly used to treat inflammations, allergies, skin conditions and even certain eye conditions, can trigger CSR, aggravate it and cause relapses. In a case report, a young male was using Prednisolone and began to display subretinal fluid indicative of CSR.
Indocyanine green angiography or laser Doppler imaging can be used to reveal the underlying swollen choroidal vessels under the retinal pigment epithelium and assess the health of the retina in the affected area which can be useful in making a treatment decision. Treatment
Any ongoing corticosteroid treatment should be tapered and stopped, where possible. It is important to check current medication, including nasal sprays and creams, for ingredients of corticosteroids, if found seek advice from a medical practitioner for an alternative. Most eyes with CSR undergo spontaneous resorption of subretinal fluid within 3–4 months. Recovery of visual acuity usually follows. Treatment should be considered if resorption does not occur within 3–4 months, spontaneously or as the result of counselling. The available evidence suggests that half-dose (or half-fluence) photodynamic therapy is the treatment of choice for CSR with subretinalfluid for longer than 3–4 months.Due to the natural disease course of CSR - in which spontaneous resolution of subretinal fluid may occur - retrospective studies may erroneously report positive treatment outcomes and should, therefore, be evaluated with caution. Laser treatments
Full-dose photodynamic therapy (PDT) with verteporfin was first described in CSR in 2003. Later, reduced-settings PDT (half-dose, half-fluence, and half-time) was found to have the same efficacy and a lower chance of complications. Follow-up studies have confirmed the treatments long-term effectiveness including its effectiveness for the chronic variant of the disease. In the PLACE trial, half-dose photodynamic therapy was found to be superior compared to high-density subthreshold micropulse laser, both with regard to anatomical and functional outcomes.