Central Serous Chorioretinopathy

Central serous chorioretinopathy is when fluid builds up under the retina. This can distort vision. The fluid leakage comes from a layer of tissue under the retina, called the choroid. There is another layer of cells called the retinal pigment epithelium (RPE). When the RPE doesn’t work as it should, fluid builds up under the RPE. As a result, a small detachment forms under the retina, causing vision to become distorted.

Central serous chorioretinopathy (CSC), the fourth most common nonsurgical retinopathy, is characterized by serous retinal detachment most commonly involving the macular region. Although natural history of CSC shows a self-limiting course, patients are known to present with persistent, recurrent, or even bilateral CSC with distressing visual loss.

This image from an OCT scan
shows how central serous
retinopathy (also called central
serous choroidopathy) causes a
blister-like swelling in layers of
the retina.

Central serous chorioretinopathy usually affects just one eye at a time, but both eyes can be affected at the same time.

Central serous chorioretinopathy symptoms

CSC typically occurs unilaterally in younger patients and is characterized by decreased and distorted vision, often associated with metamorphopsia, micropsia, mild dyschromatopsia and reduced contrast sensitivity. However, bilateral affection occurs and is more often seen in elderly patients.

CSC can occur in an acute or chronic form, but no generally accepted duration has been defined for the chronic form; many authors tend to speak of chronic CSC if symptoms last longer than 3 months, but other authors speak of chronicity if CSC alterations and symptoms are present for more than 6 months

Symptoms of central serous chorioretinopathy can include:

• distorted, dimmed, or blurred central vision
• a dark area in your central vision
• straight lines may appear bent, crooked or irregular in your affected eye
• objects may appear smaller or further away than they are
• when you look at a white object, it may appear to have a brownish tinge or appear duller in colour

Who is at risk for central serous chorioretinopathy?

Several risk factors for the development of CSC exist, but they are not fully understood, and only high serum glucocorticoid levels seem to be unambiguously related to the occurrence of CSC. Increased gluco-corticosteroid and serum catecholamine levels have been found in patients with CSC

Men in their 30s to 50s are more likely to develop central serous chorioretinopathy than women. Stress is a major risk factor. People under a lot of stress may be more likely to develop central serous chorioretinopathy.

Other risk factors for central serous chorioretinopathy are:

• use of steroids (by mouth, through a vein or even inhaled)
• Helicobacter pylori infection (a type of bacteria that can infect the stomach)
• autoimmune disease (when the body attacks its own tissues)
• sleep disturbances like insomnia (having trouble falling asleep or staying asleep)
• type A behaviour (aggressive and competitive behaviour)
• hypertension (high blood pressure)

Further risk factors that have been proposed include pregnancy, alcohol consumption, untreated hypertension, use of antibiotics, bone marrow or organ transplantation, infection of the respiratory tract.

Cause of Central Serous Chorioretinopathy

The current idea of the pathophysiology of CSC mainly proclaims choroidal vascular hyperpermeability to be the major reason for the increased tissue hydrostatic pressure beneath the RPE that can eventually lead to disintegrity of the continuity of the RPE. The observation that the retinal detachment regresses once the fluorescein leakage from one or multiple sites stops, as found by FA, has been interpreted as showing that there was a lesion of the RPE leading to subretinal accumulation of fluid originating from the choroid

Central Serous Chorioretinopathy Diagnosis – Imaging in CSC

Your ophthalmologist dilates (widens) your eye with dilating eye drops to look at your retina.

He or she will then take special photographs of your eye. During fluorescein angiography, a dye is injected into a vein in your arm. The dye travels throughout the body, including your eyes. Your doctor takes photographs of your eye as the dye passes through the retinal blood vessels. The orange dye will show abnormal areas in your eye. This can help find areas with central serous chorioretinopathy.

Optical coherence tomography (OCT) also helps your doctor look at the retina. A machine scans the back of the eye and provides detailed three-dimensional pictures of the retina. This helps measure retinal thickness and find swelling of the retina.

Imaging in CSC

Imaging techniques such as FA or ICGA have been very helpful tools for gaining a better understanding of the pathophysiology of CSC and for supporting a diagnosis of CSC. However, a better knowledge of risk factors and patient characteristics as well as gradual improvements in clinical description have led to the situation that most CSC cases can be sufficiently diagnosed without further need for imaging devices. Apart from invasive imaging tools such as FA and ICGA, novel developments including OCT with enhanced depth imaging and fundus autofluorescence imaging (FAF) may contribute to a deeper understanding of the disease.

• Fluorescein Angiography

Angiographic findings for acute CSC are characterized by focal fluorescein leaks at the level of the RPE leading to subretinal accumulation of dye. Three different manifestations have been described and include ‘smokestack leak’ and ‘inkblot leak’ patterns, depending on the nature of the protein in the subretinal fluid and the morphology of the altered RPE.

• Indocyanine Green Angiography

In CSC, an inner choroidal staining can typically be appreciated as a possible sign of fibrin. This staining appears in the midphase of the ICGA and fades in the late phase, which allows for differentiation from CNV. ICGA is particularly helpful in chronic CSC patients as it is often very difficult to interpret areas of leakage on FA images, and sometimes even patients with no signs of fluorescein leakage show increased choroidal vascular hyperpermeability; however, ICGA usually does not contribute to treatment considerations.

• Optical Coherence Tomography

Spectral-domain OCT (SD-OCT) is a helpful tool in retinal diseases and also in CSC. As a non-invasive diagnostic device, it allows to capture fast and high-resolution sectional images of the retina. Several aspects of CSC have been investigated using OCT: it has been shown that the diameter of the choroidal vessels was significantly wider in affected eyes than in normal control eyes. Other groups showed differences in the architecture of the retinal area involved between acute and chronic CSC, implying that acute CSC patients have a significantly higher pure retinal layer volume but do not differ from chronic patients in terms of subretinal fluid. Furthermore, enhanced depth imaging, a new development of OCT, has provided a deeper insight into choroidal thickness. Several groups were able to prove that the choroid is thicker in patients suffering from CSC in both the affected and the fellow eye compared with normal controls, strengthening the original idea of a hyperpermeable choroid. Other OCT findings include photoreceptor elongation as well as other defects in the inner segment/outer segment band which may correlate with visual acuity prognosis.

• Fundus Autofluorescence Imaging

The RPE has been thoroughly evaluated in different diseases and its role in the pathology of CSC seems to be indisputable. This perception has been fortified by FAF findings. Due to the anatomic features of the RPE, detailed examination and imaging have been a challenge for many years. The introduction of FAF gave clinical ophthalmologists a sophisticated tool for evaluating RPE changes.

Central serous chorioretinopathy treatment

The course of the different pathogenic concepts of this disease is well reflected by the vast number of different treatment options that have been evaluated and proposed for CSC over time. These include observation and discontinuation of corticosteroids, laser approaches such as PDT, selective retinal therapy (SRT) and standard laser photocoagulation, intravitreal injections of anti-VEGF drugs and several systemic medications including carbonic anhydrase inhibitors, β-blockers and particularly aldosterone antagonists. However, even today, no therapy of CSC may be deemed to be the gold standard, although some therapies provide better evidence for their efficiency than others; thus, of the large number of therapies suggested, only a few can be recommended.

As CSC is, in most cases, self-limiting with spontaneous resolution of the subretinal fluid, observation without additional treatment for the first 3 months is usually an appropriate first approach to handling this disease in patients without exogenous corticosteroid intake and no specific wish to accelerate the healing process. If possible, and after consulting the responsible physician, further management of risk factors includes discontinuation of steroids in patients taking these for other reasons, as well as reduction and avoidance of stress. In cases of chronicity or recurrence, however, other treatment options should be considered.

Photodynamic Therapy

PDT is usually performed by administering 6 mg/m²verteporfin (Visudyne) intravenously and subsequent activation of this dye by a laser light of 689 nm wavelength at a (full) fluence of 50 J/cm². The mechanism of action is postulated to include short-term choriocapillaris hypoperfusion and long-term choroidal vascular remodelling with subsequent reduction of vascular hyperpermeability and leakage. Some side effects including RPE alterations, CNV and choroidal ischemia have been reported. In order to reduce these side effects, two modifications to conventional full-dose/fluence PDT have been proposed: (1) half-dose PDT in which the amount of verteporfin is reduced to 3 mg/m² with the same level of laser fluence (50 J/cm²) or (2) half-fluence PDT with the same concentration of verteporfin (6 mg/m²) but with only 25 J/cm² of laser fluence. Both approaches yielded favourable results in terms of visual acuity recovery as well as subretinal fluid resolution in a large number of studies with fewer side effects compared with conventional PDT.

Selective Retinal Therapy

In contrast to standard laser photocoagulation, SRT is supposed to apply laser spots only to the RPE without risk of scotoma by damaging the neurosensory retina. SRT is performed with a Q-switched, frequency-doubled Nd:YLF laser beam with a wavelength of 527 nm. This selective treatment of the RPE is meant to trigger the regeneration of the RPE and a long-term metabolic increase at the chorioretinal junction. SRT is currently not commercially available, nor do the results so far prove sufficient effects in the treatment of CSC; therefore, SRT may be a promising treatment option in the future, but further studies are needed.

Laser Photocoagulation

As in other retinal diseases such as clinically significant macular oedema in diabetic patients, laser spots are administered to focal leakages that have been identified by FA. The exact mechanism of laser photocoagulation is not known but may be based on sealing of leaking vessels as well as activation of the pumping function of the RPE. Several studies have been carried out to evaluate the role of laser photocoagulation in CSC and good evidence exists that photocoagulation leads to faster resolution of subretinal fluid. However, several studies showed that, in spite of faster subretinal fluid resolution, no significant impact on final visual acuity can be expected. Unlike SRT, standard photocoagulation has also been proposed for chronic cases of CSC and diffuse retinal pigment epitheliopathy but does not have any effect on bullous retinal detachment, a rare form of CSC. Laser photocoagulation, however, needs thorough planning and careful execution and no laser spots should be applied to very central lesions; furthermore, long-term follow-up is necessary to detect cases of CNV, a rare but severe side effect.

Although laser photocoagulation has proved its general potency in CSC, possible side effects, particularly scotoma and the development of CNV, must be considered; therefore, laser photocoagulation should be mainly discussed for patients with long-standing CSC, possibly refractory to other treatment approaches, or with a history of CSC in the fellow eye with an unfavourable visual acuity outcome.

Carbonic Anhydrase Inhibitors

Prescription of oral acetazolamide is a widespread treatment option in CSC in spite of poor evidence in terms of outcome.

Mineralocorticoid Receptor Antagonists

The exact mode of action of glucocorticoids in the pathogenesis of CSC is still not known, even though their prominent role is beyond controversy. It therefore seems obvious that one should search for treatment options targeting this track. Glucocorticoids bind to their receptor but also to the mineralocorticoid receptor (MR) that belongs to the same family. MR are present in the kidney and the vasculature and were recently demonstrated to be expressed in different cell types of the neurosensory retina

Most cases of central serous chorioretinopathy clear up in one or two months without any treatment. During this time, your ophthalmologist will look at your eye to see if the liquid is going away. Sometimes there is severe vision loss or the leakage does not go away. In these cases, laser treatment or photodynamic therapy may be used. These treatments can seal the leak and restore vision.

Most people with central serous chorioretinopathy regain good vision even without treatment. But vision may not be as good as it was before the condition. About half of patients who have had central serous chorioretinopathy will have it return. It is important to have regular follow-up exams with your ophthalmologist. This is because long-term fluid accumulation can lead to permanent vision loss.