Beyond Spontaneous Resolution: Understanding When and Why to Treat Central Serous Chorioretinopathy

Leo Sheck

minute read

Central serous chorioretinopathy (CSC) is a clinical entity characterized by the development of subretinal fluid and consequent localized neurosensory retinal detachment. Accurate diagnosis necessitates adherence to three key criteria:

absense of any macular neovascularisation
absense of inflammation, in particular posterior scleritis or Vogt-Koyanagi-Harada syndrome
evidence of choroidal thickening (pachychoroidopathy)

Epidemiological data reveals a significant gender disparity, with an incidence of 10 per 100,000 men compared to 2 per 100,000 women. Notably, a large population study indicates a lack of new CSC diagnoses in individuals over 60 or under 25 years of age. Therefore, caution should be exercised when considering a diagnosis of CSC in patients falling outside this age range, in particularly for patients over the age of 60 where macular neovascularisation is more common. Furthermore, prevalence appears to be elevated in Asian populations, while African Americans exhibit approximately half the prevalence observed in Caucasians.

Acute central serous chorioretinopathy

Acute CSC accounts for the majority of cases, marked by the spontaneous resolution of subretinal fluid within a six-month window. Fluorescein angiography typically delineates a focal point of leakage, while autofluorescence imaging characteristically lacks gravitational drainage patterns. Although the long-term visual prognosis for acute CSC is generally favorable, patients may report subtle alterations in color perception or contrast sensitivity.

A study encompassing 31 patients with acute CSC revealed a median time to resolution of three months, with 81% achieving complete fluid resorption within six months. However, the recurrence rate ranges from 30% to 50%, with a median time to recurrence of 1.3 years.

Early treatment may reduce the risk of recurrence. In a study involving 291 eyes, the following recurrence rate is noted:

24% in untreated patients
4% in patients treated with photodynamic therapy (134 cases), thermal laser (3 cases), or micropulse laser (4 cases)

Chronic central serous chorioretinopathy

Defined by the persistent presence of subretinal fluid beyond a six-month duration, chronic CSC accounts for 5-15% of all CSC cases. In contrast to its acute counterpart, fluorescein angiography in chronic CSC typically reveals diffuse leakage, and autofluorescence imaging often demonstrates characteristic gravitational fluid tracks. Patients with chronic CSC are typically older (> 40 years) and the condition exhibits a higher propensity for bilaterality, ranging from 42% to 84% of cases.

The visual prognosis in chronic CSC is considerably less favorable, with approximately 80% of patients maintaining a visual acuity of 6/12 or better in at least one eye, while a significant 13% may progress to legal blindness. Furthermore, the median time to spontaneous complete resolution in untreated chronic CSC is protracted, averaging 458 days. This underscores the critical need for timely and effective intervention in these cases.

Treatment for central serous chorioretinopathy

Half dose or half fluence photodynamic therapy

This is the treatment of choice for CSC. Published data reports the following resolution and recurrence rates with this modality in chronic CSC:

around 60% in one months
70-80% between three to nine months
up to 90% in 12 months

While standard-dose PDT carries a notable risk of choriocapillaris infarction (up to 44%), this adverse event is not generally observed with the reduced dose or fluence regimens. Other potential ocular risks associated with PDT include retinal pigment epithelium (RPE) atrophy (4%), acute exudative maculopathy, and, rarely, severe vision loss (up to 1.5%). Systemic risks related to verteporfin administration include transient photosensitivity (up to 48 hours), injection site reactions, back pain, and allergic reactions.

Direct laser photocoagulation

Direct laser photocoagulation remains a viable treatment option for CSC characterized by a focal leakage point situated outside the fovea (typically > 500µm from the foveal center). This technique typically necessitates the application of low-power laser spots to achieve effective treatment. While direct laser photocoagulation may expedite visual recovery by approximately two months, robust evidence demonstrating long-term visual benefits remains limited.

Micropulse laser

Micropulse laser therapy involves the application of very low-power laser pulses in an attempt to treat CSC while minimizing thermal damage to the surrounding retinal tissues. However, the findings of the PLACE trial indicate that micropulse laser is significantly less effective than half-dose or half-fluence PDT in achieving complete resolution of subretinal fluid. Consequently, PDT remains the preferred treatment strategy for CSC.

Who to treat?

In the majority of cases involving acute central serous chorioretinopathy, immediate treatment is not typically warranted due to the favorable natural history of the condition and the high rate of spontaneous resolution. However, intervention may be considered in specific circumstances where patients require rapid visual improvement, often dictated by occupational demands, or patients are specifically concerned regarding recurrence risk. Furthermore, bear in mind that the median resolution time is three months in acute CSC, so if there is no sign of improvement in the subretinal fluid after 3-4 months, the possibility of treatment will have to be discussed.

Conversely, a proactive treatment approach is generally recommended for all patients diagnosed with chronic central serous chorioretinopathy, given the less predictable and often poorer long-term visual outcomes associated with this persistent form of the disease. This includes patients with subretinal fluid persisting for more than six months, or those presenting with new-onset fluid accumulation in conjunction with pre-existing fluid tracks observed on autofluorescence imaging. In these scenarios, half-dose photodynamic therapy represents my preferred treatment modality. Its broader treatment field compared to direct laser photocoagulation allows for comprehensive management of diffuse leakage, effectively accelerating fluid resorption and potentially reducing the risk of future recurrences.